US20050224469A1 - Efficient micro-machining apparatus and method employing multiple laser beams - Google Patents
Efficient micro-machining apparatus and method employing multiple laser beams Download PDFInfo
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- US20050224469A1 US20050224469A1 US11/000,333 US33304A US2005224469A1 US 20050224469 A1 US20050224469 A1 US 20050224469A1 US 33304 A US33304 A US 33304A US 2005224469 A1 US2005224469 A1 US 2005224469A1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/062—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam
- B23K26/0622—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/08—Devices involving relative movement between laser beam and workpiece
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/38—Removing material by boring or cutting
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/26—Bombardment with radiation
- H01L21/263—Bombardment with radiation with high-energy radiation
- H01L21/268—Bombardment with radiation with high-energy radiation using electromagnetic radiation, e.g. laser radiation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/005—Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping
Definitions
- This invention relates to lasers and, more particularly, to a method and an apparatus for increasing workpiece machining throughput by alternately switching a single laser beam among two or more beam paths such that one of the beam paths is employed for machining one workpiece while another the beam path is positioned for machining another workpiece.
- Lasers are widely employed in a variety of research, development, and industrial operations including inspecting, processing, and micromachining a variety of electronic materials and substrates.
- DRAM dynamic random access memory
- laser pulses are used to sever electrically conductive links to disconnect faulty memory cells from a DRAM device and then to activate redundant memory cells to replace the faulty memory cells. Because faulty memory cells needing link removals are randomly located, the links that need to be severed are randomly located.
- the laser pulses are fired at random pulse intervals.
- the laser pulses are running at a wide variable range of pulse repetition frequencies (“PRFs”), rather than at a constant PRF.
- PRFs pulse repetition frequencies
- the laser pulse is fired at the target link without stopping the laser beam scanning mechanism.
- This production technique is referred to in the industry as “on-the-fly” (“OTF”) link processing.
- OTF on-the-fly
- Other common laser applications employ laser pulses that are fired only when they are needed at random times.
- the laser energy per pulse typically decreases with increasing PRF while laser pulse width increases with increasing PRF, characteristics that are particularly true for Q-switched, solid-state lasers.
- many laser applications require randomly time-displaced laser pulses on the demand, these applications also require that the laser energy per pulse and the pulse width be kept substantially constant.
- inadequate laser energy will result in incomplete link severing, while excessive laser energy will cause unacceptable damage to the passivation structure or the silicon substrate.
- the acceptable range of laser pulse energies is often referred to as a “process window.”
- the process window requires that laser pulse energy vary by less than 5 percent from a selected pulse energy value.
- U.S. Pat. No. 5,226,051 for LASER PUMP CONTROL FOR OUTPUT POWER STABILIZATION describes a technique of equalizing the laser pulse energy by controlling the electrical current of the pumping diodes. The technique works well in practical applications employing a laser PRF below about 25 KHz or 30 KHz.
- UV ultraviolet
- UV energy wavelengths may be generated by subjecting an IR laser to a harmonic generation process that stimulates the second, third, or fourth harmonics of the IR laser.
- the pulse-to-pulse energy levels of such UV lasers are particularly sensitive to time variations in PRF and laser pulse interval.
- U.S. Pat. No. 6,172,325 for LASER PROCESSING POWER OUTPUT STABILIZATION APPARATUS AND METHOD EMPLOYING PROCESSING POSITION FEEDBACK which is also assigned to the assignee of this patent application, describes a technique of operating the laser at a constant high repetition rate in conjunction with a position feedback-controlled laser pulse picking or gating device to provide laser pulse picking on demand at a random time interval that is a multiple of the laser pulse interval. This technique affords good laser pulse energy stability and high throughput.
- a typical laser pulse picking or gating device is an acousto-optic modulator (“AOM”) or electro-optic modulator (“EOM”, also referred to as a Pockels cell).
- AOM acousto-optic modulator
- EOM electro-optic modulator
- Typical EOM material such as KD*P or KDP suffers from relatively strong absorption at the UV wavelengths, which results in a lower damage threshold of the material at the wavelength used and local heating along the laser beam path within the device, causing changes of the half wave-plate voltage of the device.
- Another disadvantage of the EOM is its questionable ability to perform well at a repetition rate over 50 KHz.
- AOM material is, on the other hand, quite transparent to UV light of 250 nm up to IR light of 2,000 nm, which allows the AOM to perform well throughout typical laser wavelengths within the range.
- An AOM can also easily accommodate the desirable gating of pulses at a repetition rate of up to a few hundred KHz.
- One disadvantage of the AOM is its limited diffraction efficiency of about 75-90 percent.
- FIG. 1 shows a typical prior art AOM 10 driven by a radio frequency (“RF”) driver 12 and employed for a laser pulse picking or gating application
- FIGS. 2A to 2 D show corresponding prior art timing graphs for incoming laser pulses 14 , AOM RF pulses 15 , and AOM output pulses 16 and 20
- FIG. 2A shows constant repetition rate laser pulses 14 a - 14 k that are emitted by a laser (not shown) and propagated to AOM 10 .
- FIG. RF radio frequency
- FIGS. 2C and 2D show the respective first order beam 20 and zero order beam 16 propagated from AOM 10 , as determined by the presence or absence of RF pulses 15 applied to AOM 10 .
- AOM 10 is driven by RF driver 12 .
- incoming laser pulses 14 pass through AOM 10 substantially along their original beam path and exit as beam 16 , typically referred to as the zero order beam 16 .
- RF pulses 15 are applied to AOM 10 , part of the energy of incoming laser pulses 14 is diffracted from the path of the zero order beam 16 to a path of a first order beam 20 .
- AOM 10 has a diffraction efficiency that is defined as the ratio of the laser energy in first order beam 20 to the laser energy in incoming laser pulses 14 .
- Either first order beam 20 or zero order beam 16 can be used as a working beam, depending on different application considerations.
- laser pulses 14 entering AOM 10 will hereafter be referred as “laser pulses” or “laser output,” and pulses delivered to the target, because they are picked by AOM 10 , will be referred to as “working laser pulses” or “working laser output.”
- first order beam 20 When first order beam 20 is used as the working beam, the energy of the working laser pulses can be dynamically controlled from 100 percent of its maximum value down to substantially zero, as the power of RF pulses 15 changes from their maximum power to substantially zero, respectively. Because the practical limited diffraction efficiency of an AOM under an allowed maximum RF power load is about 75 percent to 90 percent, the maximum energy value of the working laser pulses is about 75 percent to 90 percent of the energy value in laser pulses 14 . However, when zero order beam 16 is used as the working beam, the energy of the working laser pulses can be dynamically controlled from 100 percent of the maximum energy in laser pulses 14 down to 15 percent to 20 percent of the maximum value, as the power of RF pulses 15 changes from substantially zero to its maximum power, respectively. For memory link processing, for example, when no working laser pulse is demanded, no leakage of system laser pulse energy is permitted, i.e., the working laser pulse energy should be zero, so first order laser beam 20 is preferably used as the working beam.
- RF pulses 15 are applied to AOM 10 at random time intervals and only when working laser pulses are demanded, in this case, at random integral multiples of the laser pulse interval.
- the random output of working laser pulses results in random variable thermal loading on AOM 10 .
- Variable thermal loading causes geometric distortion and temperature gradients in AOM 10 , which cause gradients in its refractive index.
- the consequences of thermal loading distort a laser beam passing through AOM 10 , resulting in deteriorated laser beam quality and instability in the laser beam path or poor beam positioning accuracy. These distortions could be corrected to some degree if they could be kept constant. However, when the system laser pulses are demanded randomly, such as in laser link processing, these distortions will have the same random nature and cannot be practically corrected.
- What is also needed is an apparatus and a method of generating working laser pulses having constant laser energy per pulse and constant pulse width on demand and/or on-the-fly at a high PRF and with high accuracy at different pulse time intervals for variety of laser applications such as laser link processing on memory chips.
- an efficient, high-throughput apparatus and method for utilizing the working laser pulses is an efficient, high-throughput apparatus and method for utilizing the working laser pulses.
- An object of this invention is, therefore, to provide an apparatus and a method for picking laser pulses on demand from a high repetition rate pulsed laser.
- Embodiments of this invention perform such pulse picking with minimal thermal loading variation on the AOM to minimize distortion of the laser beam and positioning accuracy. They include an apparatus and a method for generating system on demand laser pulses having stable pulse energies and stable pulse widths at selected wavelengths from the UV to near IR and at high PRFs for high-accuracy laser processing applications, such as memory link severing.
- the embodiments of this invention provide an efficient, high-throughput apparatus and method for utilizing the working laser pulses.
- a workpiece processing system of this invention employs a laser coupled to a beam switching device that causes a laser beam or laser pulses to switch between first and second beam positioning heads such that when the first beam positioning head directs the laser beam to process a first workpiece, the second beam positioning head moves to a next target location on a second workpiece or a second set of locations on the first workpiece.
- the beam switching device causes the beam to switch to the second beam positioning head and then the second beam positioning head directs the laser beam to target locations on the second workpiece while the first beam positioning head moves to its next target position.
- An advantage of the present laser beam switching system is that the first and second workpieces receive almost the full power of the laser beam for processing.
- the total time utilization of the laser beam is increased by almost a factor of two, depending on the processing-to-moving time ratio. This greatly increases system throughput without significantly increasing system cost.
- a preferred beam switching device includes first and second AOMs that are positioned adjacent to each other so that the laser beam (or laser pulses) normally pass undeflected through the AOMs and terminate on a beam blocker.
- first and second AOMs that are positioned adjacent to each other so that the laser beam (or laser pulses) normally pass undeflected through the AOMs and terminate on a beam blocker.
- first AOM When RF energy is applied to the first AOM, about 90 percent of the laser beam is diffracted as a first laser beam and 10 percent remains as a residual laser beam that terminates in the beam blocker.
- RF energy is applied to the second AOM, about 90 percent of the laser beam is diffracted as a second laser beam and 10 percent remains as a residual laser beam that terminates in the beam blocker.
- the laser generating the laser beam is constantly running at its desired pulse repetition rate.
- Employing the beam switching device is advantageous because constant operation of the laser eliminates thermal drifting of the laser output. Moreover, by operating the first and second AOMs with pulse picking methods of this invention, thermal loading variations in the AOMs will be minimized, thereby increasing laser beam positioning accuracy.
- first and second AOMs as a beam switching device are capable of operating as a laser power control device, eliminating a need for a separate laser power controller in a typical laser-based workpiece processing system. Power control is possible because the response times of the AOMs are sufficiently fast for programming laser pulse amplitudes of the switched laser beam during processing of individual target locations on the workpieces.
- a typical laser processing application is blind via formation in etched-circuit boards, in which it is often necessary to reduce the laser pulse energy when the laser beam reaches the bottom of the via being formed.
- FIG. 1 is a simplified schematic view of a prior art AOM device and an RF driver, transmitting a zero order beam, a first order beam, or both of them.
- FIGS. 2A-2D are corresponding prior art timing graphs of, respectively, laser pulses, RF pulses, and first and zero order AOM output laser pulses.
- FIGS. 3A-3C are corresponding exemplary timing graphs of, respectively, laser outputs, RF pulses, and working laser outputs as employed in a preferred embodiment.
- FIGS. 4A-4C are alternative corresponding exemplary timing graphs of, respectively, laser outputs, RF pulses, and working laser outputs that demonstrate the use of the AOM for energy control of the working laser outputs.
- FIG. 5 is a simplified schematic block diagram of a laser beam switching system of this invention.
- FIG. 6 is a waveform timing diagram representing operational timing relationships among various components of the laser beam switching system of FIG. 5 .
- FIG. 7 is a simplified schematic block diagram representing a preferred dual AOM laser beam switching device for use with this invention.
- FIG. 8 is a waveform timing diagram representing operational timing relationships among various components of a laser beam switching system employing the dual AOM switching device of FIG. 7 .
- FIG. 9 is a simplified schematic block diagram of a typical workpiece processing system employing the laser beam switching device of FIG. 7 .
- FIG. 10 is a waveform timing diagram representing operational timing relationships among various components of the workpiece processing system of FIG. 9 .
- FIGS. 11A and 11B are simplified block diagrams representing workpiece processing systems of this invention employing a common optical processing path for multiple laser beams propagating from one and two laser sources, respectively.
- FIG. 12 is a simplified schematic block diagram representing an alternative workpiece processing system of this invention employing a fast EOM and a polarizing beam splitter to implement a laser beam switching device of this invention.
- FIG. 13 is a simplified pictorial block diagram representing an alternative laser beam switching system employing a fast steering mirror for switching a laser beam along alternate first and second pathways.
- FIGS. 3A-3C show corresponding timing graphs of laser outputs 24 a - 24 k (collectively, laser outputs 24 ), RF pulses 38 a - 38 k (collectively, RF pulses 38 ) applied to prior art AOM 10 , and working laser outputs 40 a , 40 c , 40 d , 40 e , and 40 i (collectively, working laser outputs 40 ).
- FIG. 3 show corresponding timing graphs of laser outputs 24 a - 24 k (collectively, laser outputs 24 ), RF pulses 38 a - 38 k (collectively, RF pulses 38 ) applied to prior art AOM 10 , and working laser outputs 40 a , 40 c , 40 d , 40 e , and 40 i (collectively, working laser outputs 40 ).
- FIG. 3A-3C show corresponding timing graphs of laser outputs 24 a - 24 k (collectively, laser outputs 24 ), RF pulses 38
- each of working laser outputs 40 preferably includes a single laser pulse having a multiple nanosecond pulse width.
- each of working laser outputs 40 may include a burst of one or more laser pulses, such as disclosed in U.S. Pat. No.
- FIG. 3B shows a preferred RF pulse picking scheme employing RF pulses 38 having pulse durations, such as 42 a and 42 b (collectively, RF pulse durations 42 ) separated by RF pulse intervals 43 a - 43 j (collectively, RF pulse intervals 43 ) that are substantially regular or uniform to keep thermal loading variations on AOM 10 within a preassigned operational tolerance.
- Such tolerance may be a specific thermal load window, but the preassigned tolerance may also or alternatively be windows of spot size or beam position accuracy.
- the thermal loading variation is maintained within 5 percent and/or the beam pointing accuracy is maintained within 0.005 milliradian.
- at least one of RF pulses 38 is generated to correspond with each of laser outputs 24 .
- one of RF pulses 38 is applied to AOM 10 in coincidence with one of laser outputs 24 such that it is transmitted through AOM 10 and becomes the demanded one of working laser outputs 40 .
- the coincident RF pulses 38 are RF pulses 38 a , 38 c , 38 d , 38 e , and 38 i.
- FIG. 3C shows the resulting corresponding working laser outputs 40 a , 40 c , 40 d , 40 e , and 40 i .
- RF pulses 38 are applied to AOM 10 in noncoincidence with corresponding ones of laser outputs 24 .
- the noncoincident RF pulses 38 are RF pulses 38 b , 38 f , 38 g , 38 h , 38 j , and 38 k .
- FIG. 3C shows that no working laser outputs 40 correspond with noncoincident RF pulses 38 .
- the noncoincident RF pulses 38 are preferably offset from the initiations of respective laser outputs 24 by time offsets 44 that are longer than about 0.5 microsecond. Skilled persons will appreciate that while time offsets 44 are shown to follow laser outputs 24 , time offsets 44 could alternatively precede laser outputs 24 by a sufficient time to prevent targeting of laser working outputs 40 .
- RF pulse intervals 43 surrounding one of noncoincident RF pulses 38 may be shorter (such as RF pulse intervals 43 b and 43 h ) than the overall average RF pulse interval 43 (such as 43 c , 43 d , 43 f , 43 g , and 43 j ) or longer (such as RF pulse intervals 43 a , 43 e , and 43 i ) than the average RF pulse intervals 43 .
- nonimpingement intervals 46 b and 46 c between working laser outputs 40 c and 40 d and between working laser outputs 40 d and 40 e , respectively, are about the same as the laser output interval 41 .
- the nonimpingement intervals 46 a and 46 d between working laser outputs 40 a and 40 c and between working laser outputs 40 e and 40 i , respectively, are roughly integer multiples of the laser output interval 41 .
- working laser outputs 40 are preferably first order beam 20 for most applications, such as link processing, working laser outputs 40 may be zero order beam 16 where leakage is tolerable and higher working laser output power is desirable.
- the coincident and noncoincident RF pulses 38 not only employ about the same RF energy, which is the product of an RF power value and an RF duration, but also employ about the same RF power value and about the same RF duration.
- FIGS. 4A-4C show corresponding timing graphs of laser outputs 24 , RF pulses 38 applied to AOM 10 , and working laser outputs 40 that demonstrate how AOM 10 can be additionally employed to control the output power of working laser outputs 40 .
- FIG. 4A is identical to FIG. 3A and is shown for convenience only.
- FIGS. 4B and 4C show RF pulses 38 ′ and working laser outputs 40 ′, with the corresponding RF pulses 38 and working laser outputs 40 shown superimposed on them in dashed lines for convenience.
- the energy values of working laser outputs 40 ′ are attenuated by applying less RF power to AOM 10 for RF pulses 38 ′ than for RF pulses 38 ; however, the RF pulse durations 42 ′ are increased for RF pulses 38 ′ over the RF durations 42 employed for RF pulses 38 to maintain a substantially constant product of RF power value and RF duration in order to maintain substantially constant thermal loading on AOM 10 .
- This technique permits on-demand selection for a continuum of output powers between working laser outputs 40 or 40 ′ without substantial variance in thermal loading on AOM 10 .
- the RF power values and RF durations 42 of the noncoincident RF pulses 38 can be kept as original or can be altered to be within a specified tolerance of the RF loading variation of the coincident RF pulses 38 ′.
- RF pulse duration 42 ′ is preferably selected from about one microsecond to about one-half of laser output interval 41 , more preferably shorter than 30 percent of laser output interval 41 .
- RF pulse duration 42 ′ can be anywhere between one microsecond and ten microseconds.
- the minimum RF pulse duration 42 or 42 ′ is determined by the laser pulse jittering time and the response time of AOM 10 . It is preferable to initiate corresponding ones of RF pulses 38 and 38 ′ surrounding the midpoints of laser outputs 24 . Likewise, it is preferable for RF pulses 38 and 38 ′ to be delayed or offset about half of the minimum RF pulse duration from the initiation of corresponding laser outputs 24 .
- RF power of RF pulses 38 applied to AOM 10 can be adjusted to control the energy of working laser outputs 40 and 40 ′ to meet target processing needs, while RF pulse durations 42 and 42 ′ of RF pulses 38 and 38 ′ can be controlled accordingly to maintain a substantially constant RF energy or arithmetic product of the RF powers and durations of RF pulses 38 and 38 ′.
- This invention provides apparatus and methods for improving the throughput and efficiency of a single laser workpiece processing system.
- AOMs employing pulse picking techniques are used in combination with a laser beam switching, or multiplexing, technique to improve workpiece processing and efficiency.
- FIGS. 5 and 6 represent a laser beam switching system 50 and associated timing aspects of this invention in which a laser emits laser pulses 54 that are reflected by an optional fold mirror 56 to a beam switching device 58 .
- Beam switching device 58 causes laser pulses 54 to switch between first and second beam positioning heads 60 and 62 such that when first beam positioning head 60 is causing laser pulses 54 to process a target location on a first workpiece 64 , second beam positioning head 62 is moving to a target location on a second workpiece 66 .
- Laser pulses 54 are directed from beam switching device 58 to beam positioning head 62 by an optional fold mirror 68 .
- first beam positioning head 60 completes processing of workpiece 64 , either an optional shutter (not shown), such as a Q-switch, turns laser 52 off, as shown in FIG. 6 , or laser pulses 54 are dumped. to a beam blocker (not shown).
- second beam positioning head 62 reaches its target position, laser pulses 54 are switched on by the shutter and second beam positioning head 62 directs laser pulses 54 to target locations on workpiece 66 while first beam positioning head 60 moves to its next target position.
- FIG. 6 represents workpiece processing times as intervals P and positioner move times between target positions as intervals M.
- An advantage of laser beam switching system 50 is that first and second workpieces 64 and 66 alternately receive almost the full power of laser pulses 54 for processing.
- the total time utilization of laser pulses 54 is increased by almost a factor of two, depending on the processing-to-moving time ratio. This greatly increases system throughput without significantly increasing system cost.
- FIGS. 7 and 8 show a preferred beam switching device 70 and related timing relationships.
- Beam switching device 70 includes first and second AOMs 72 and 74 positioned in optical series relation so that a laser beam or laser pulses 76 normally pass undeflected through AOMs 72 and 74 and terminate as laser beam 76 A on a beam blocker 78 .
- a first RF driver 80 applies about 6 Watts of 85 MHz RF signal to first AOM 72
- about 90 percent of laser beam 76 is diffracted as laser beam 76 B and 10 percent remains as laser beam 76 A.
- a second RF driver 82 applies about 6 Watts of 85 MHz RF signal to second AOM 74 , about 90 percent of laser beam 76 is diffracted as laser beam 76 C and 10 percent remains as laser beam 76 A.
- the laser generating laser beam 76 is constantly running at its desired pulse repetition rate.
- Beam switching device 70 is advantageous because constant operation of the laser eliminates thermal drifting of the laser output. Moreover, by operating AOMs 72 and 74 with the pulse picking methods described with reference to FIGS. 3 and 4 , thermal loading variations will be minimized, thereby increasing laser beam positioning accuracy.
- Each of first and second AOMs 72 and 74 is preferably a Model N30085, manufactured by NEOS Technologies, Inc., of Melbourne, Florida. The N30085 AOM has a specified 90 percent diffraction efficiency when driven with two Watts of 85 MHz RF power.
- beam switching device 70 can operate as a laser power control device, eliminating a need for a separate laser power controller in a typical laser-based workpiece processing system. Power control is possible because the response times of AOMs 72 and 74 are sufficiently fast for programming laser pulse amplitudes of laser beams 76 B and 76 C during processing of single target locations in workpieces.
- a typical laser processing application is blind via formation in etched-circuit boards, in which it is often necessary to reduce the laser pulse energy when the laser beam reaches the bottom of the via being formed.
- FIGS. 9 and 10 show, respectively, a typical workpiece processing system 90 employing beam switching device 70 and related operational timing relationships.
- a laser 92 and a variable beam expander 94 cooperate to produce laser beam 76 that propagates through beam switching device 70 , which operates as described with reference to FIGS. 7 and 8 to produce laser beams 76 A, 76 B, and 76 C.
- Laser beam 76 A terminates in beam blocker 78 .
- Laser beam 76 B is reflected by an optional fold mirror 96 and directed by a first XY scanner 98 to target locations 1 , 2 , 3 , and 4 on a first workpiece 100 .
- laser beam 76 C is reflected by an optional fold mirror 102 and directed by a second XY scanner 104 to target locations 1 , 2 , 3 , and 4 on a second workpiece 106 .
- First and second XY scanners 98 and 104 are mounted on respective first and second X positioning stages 108 and 110
- first and second workpieces 100 and 106 are mounted on a Y positioning stage 112 .
- Skilled workers will understand that the scanners and workpieces are mounted on a split axis configured positioner system but that planar and stacked configurations may alternatively be employed. Skilled workers will also understand that the target locations on the first and second workpieces may be on a common substrate and/or may not share corresponding target locations.
- FIG. 10 shows laser beam 76 B processing (drilling) target location 1 on workpiece 100 while second XY scanner 104 is moving the position of laser beam 76 C to target location 1 on workpiece 106 .
- first XY scanner 98 is moving the position of laser beam 76 B to target location 2 on workpiece 100 . This process continues for target locations 2 , 3 , and 4 until processing of target location 4 on workpiece 106 is complete, at which time first and second X positioning stages 108 and 110 and Y positioning stage 112 execute a long move to position first and second XY scanners 98 and 104 over target locations 5 , 6 , 7 , and 8 of respective workpieces 100 and 106 .
- the X and Y linear positioning stages operate in constant motion in cooperation with the XY scanners.
- Positioning systems suitable for use with this invention are described in U.S. Pat. No. 5,751,585 for HIGH SPEED, HIGH ACCURACY MULTI-STAGE TOOL POSITIONING SYSTEM, which is assigned to the assignee of this patent application.
- FIG. 11 A shows a workpiece processing system 120 of this invention that employs a common modular imaged optics assembly 122 and variable beam expander 94 for optically processing both laser beams 76 B and 76 C.
- laser 92 and an optional fixed beam expander 124 cooperate to produce laser beam 76 that propagates through beam switching device 70 , which operates as described with reference to FIGS. 7 and 8 to produce laser beams 76 A, 76 B, and 76 C.
- Laser beams 76 B and 76 C propagate along separate propagation path portions.
- a first turn mirror 126 directs laser beam 76 B through a half-wave plate 128 , which changes the polarization state of laser beam 76 B by 90 degrees relative to the polarization state of laser beam 76 C.
- the 90 degree phase-displaced laser beam 76 B is directed by a second turn mirror 130 to a polarizing beam combiner 132 .
- Laser beam 76 C is directed by a third turn mirror 134 to polarizing beam combiner 132 , which combines into a common propagation path portion the separate path portions along which laser beams 76 B and 76 C propagate.
- Laser beams 76 B and 76 C merge into a common laser beam 76 D, which propagates along the common path portion through imaged optics assembly 122 and optional variable expander 94 and into a polarizing beam splitter 136 .
- Second polarizing beam splitter 136 separates common laser beam 76 D into laser beams 76 B and 76 C.
- Laser beam 76 B is directed by a fourth turn mirror 138 into, for example, first XY scanner 98 ; and laser beam 76 C is directed into, for example, second XY scanner 104 .
- Beam expander 124 sets the shape of laser beams 76 B and 76 C in the form of a Gaussian spatial distribution of light energy.
- Imaged optics assembly 122 shapes the Gaussian spatial distribution of lasers 76 B and 76 C to form output beams of uniform spatial distribution for delivery to XY scanners 98 and 104 .
- a preferred imaged optics assembly is of a diffractive beam shaper type such as that described in U.S. Pat. No. 5,864,430.
- FIG. 11B shows an alternative workpiece processing system 120 ′, in which beam switching device 70 is removed and laser beams 76 B and 76 C propagate from separate laser sources 92 b and 92 c , respectively.
- the size of laser beam 76 B is set by a beam expander 124 b
- the size of laser beam 76 C is set by a beam expander 124 c .
- the use of separate laser sources 92 b and 92 c facilitates optical component configurations in which one or more of turn mirrors 126 , 130 , and 134 can be eliminated, as shown in FIG. 11B .
- Each of workpiece processing systems 120 and 120 ′ is advantageous because only one set of expensive beam imaging optics is required. Moreover, for workpiece processing system 120 , employing beam switching device 70 permits implementation with smaller optical components because switching is accomplished with a smaller beam width than that which would be found with downstream switching components.
- FIG. 12 shows another alternative workpiece processing system 140 of this invention employing a fast EOM 142 and a polarizing beam splitter 144 to implement switching of a laser beam 146 between first and second XY beam scanning heads 98 and 104 .
- laser 92 emits laser beam 146 , which propagates through and is optically processed by an optics module 148 and a laser power controller 150 .
- Laser beam 146 exits laser power controller 150 and enters fast EOM 142 , which alternately polarizes laser beam 146 into respective unrotated-polarization and rotated-polarization laser beams 146 U and 146 R.
- Polarizing beam splitter 144 receives unrotated laser beam 146 U and directs it to a turn mirror 152 to first XY scanning head 98 .
- Polarizing beam splitter 144 receives rotated laser beam 146 R and directs it to second XY scanning head 104 .
- a disadvantage of workpiece processing system 140 is that current practical EOMs are limited in laser pulse repetition rates and are unable to withstand high amounts of ultraviolet laser beam power. Another limitation is that dumping unneeded laser beam energy requires shuttering or turning off laser 92 , such as by a Q-switch positioned inside the cavity of laser 92 .
- workpiece processing system 140 is advantageous because it is simpler than the dual AOM beam switching device 70 described with reference to FIG. 7 and has a high extinguishing ratio that allows practically all of the power in laser beam 146 to impinge on target locations as laser beams 146 U and 146 R.
- FIG. 13 shows an alternative embodiment of a laser beam switching system 210 in which a laser 212 emits a laser beam 214 that is deflected by a fast steering mirror (“FSM”) 216 along alternate first and second paths 218 and 220 .
- FSM 216 preferably employs a mirror having a deflection angle that is controlled by materials that translate voltages into angular displacements.
- FSM 216 operates similar to a galvanometer driven rotating mirror but at angular speeds up to 10 times faster than galvanometers and over an angular deflection range 222 of up to about 5 milliradians.
- Deflecting a typical laser beam diameter with such a limited angular deflection range requires a path length 224 that is sufficiently long, preferably about one meter, to separate first and second beam paths 218 and 220 by a sufficient distance 226 , preferably about 10 millimeters, for inserting between them an HR coated right angle prism 228 that further separates and directs first and second beams baths 218 and 220 for reflection by respective first and second turning mirrors 230 and 232 to associated laser beam scanning heads (not shown).
- Switching laser beam 214 at a location where it is smallest in diameter, such as before any beam expander, would minimize path length 224 required to sufficiently separate first and second paths 218 and 220 where they are reflected by right angle prism 228 .
- FSM 216 may be a two-axis device that could further provide switching of laser beam 214 to more than two positions.
- laser beam 214 could be directed to a beam blocker during long moves as described with reference to FIGS. 9 and 10 to maintain constant thermal conditions in laser 212 and minimize duty cycle related laser beam power stability problems.
- Laser beam switching system 210 allows implementing a single laser workpiece processing system having the same workpiece processing throughput as a two laser system, provided the move times are over 3 ms and the workpiece processing time and laser beam switching time are less than 1.0 ms.
- Laser beam switching system 210 is advantageous because the use of a single laser and associated optics reduces cost by 20 percent to 40 percent, depending on the type of laser required, as compared with a two laser system.
- galvonometer and rotating mirror devices may also be used as laser beam switching devices; IR, visible, and UV lasers may be employed; target locations may be on single or multiple workpieces; laser beam switching may be effected to more than two or three beam paths; multiple lasers may be employed and each of their respective laser outputs switched among multiple paths; AOMs may be switched by single or multiple RF sources; and the scanning heads employed may further include galvanometers, FSMs, and other than XY coordinate positioning techniques.
Abstract
A laser beam switching system employs a laser coupled to a beam switching device that causes a laser beam to switch between first and second beam positioning heads such that while the first beam positioning head is directing the laser beam to process a workpiece target location, the second beam positioning head is moving to another target location and vice versa. A preferred beam switching device includes first and second AOMs positioned such that the laser beam passes through the AOMs without being deflected. When RF is applied to the first AOM, the laser beam is diffracted toward the first beam positioning head, and when RF is applied to the second AOM, the laser beam is diffracted toward the second beam positioning head.
Description
- This is a continuation-in-part of U.S. patent application Ser. No. 10/611,798, filed Jun. 30, 2003.
- Not applicable
- This invention relates to lasers and, more particularly, to a method and an apparatus for increasing workpiece machining throughput by alternately switching a single laser beam among two or more beam paths such that one of the beam paths is employed for machining one workpiece while another the beam path is positioned for machining another workpiece.
- Lasers are widely employed in a variety of research, development, and industrial operations including inspecting, processing, and micromachining a variety of electronic materials and substrates. For example, to repair a dynamic random access memory (“DRAM”), laser pulses are used to sever electrically conductive links to disconnect faulty memory cells from a DRAM device and then to activate redundant memory cells to replace the faulty memory cells. Because faulty memory cells needing link removals are randomly located, the links that need to be severed are randomly located. Thus, during the laser link repairing process, the laser pulses are fired at random pulse intervals. In another words, the laser pulses are running at a wide variable range of pulse repetition frequencies (“PRFs”), rather than at a constant PRF. For industrial processes to achieve greater production throughput, the laser pulse is fired at the target link without stopping the laser beam scanning mechanism. This production technique is referred to in the industry as “on-the-fly” (“OTF”) link processing. Other common laser applications employ laser pulses that are fired only when they are needed at random times.
- However, the laser energy per pulse typically decreases with increasing PRF while laser pulse width increases with increasing PRF, characteristics that are particularly true for Q-switched, solid-state lasers. While many laser applications require randomly time-displaced laser pulses on the demand, these applications also require that the laser energy per pulse and the pulse width be kept substantially constant. For link processing on memory or other IC chips, inadequate laser energy will result in incomplete link severing, while excessive laser energy will cause unacceptable damage to the passivation structure or the silicon substrate. The acceptable range of laser pulse energies is often referred to as a “process window.” For many practical IC devices, the process window requires that laser pulse energy vary by less than 5 percent from a selected pulse energy value.
- Various approaches have been implemented to ensure operation within a process window or to expand the process window. For example, U.S. Pat. No. 5,590,141 for METHOD AND APPARATUS FOR GENERATING AND EMPLOYING A HIGH DENSITY OF EXCITED IONS IN A LASANT, which is assigned to the assignee of this patent application, describes solid-state lasers having lasants exhibiting a reduced pulse energy drop off as a function of increasing PRF and, therefore, a higher usable PRF. Such lasers are, therefore, capable of generating more stable pulse energy levels when operated below their maximum PRFs.
- U.S. Pat. No. 5,265,114 for SYSTEM AND METHOD FOR SELECTIVELY LASER PROCESSING A TARGET STRUCTURE OF ONE OR MORE MATERIALS OF A MULTIMATERIAL, MULTILAYER DEVICE, which is also assigned to the assignee of this patent application, describes using a longer laser wavelength such as 1,320 nanometers (“nm”) to expand the link process window to permit a wider variation of the laser pulse energy during the process.
- U.S. Pat. No. 5,226,051 for LASER PUMP CONTROL FOR OUTPUT POWER STABILIZATION describes a technique of equalizing the laser pulse energy by controlling the electrical current of the pumping diodes. The technique works well in practical applications employing a laser PRF below about 25 KHz or 30 KHz.
- The above-described laser processing applications typically employ infrared (“IR”) lasers having wavelengths from 1,047 nm to 1,324 nm, running at PRFs not over about 25 to 30 KHz. However, production needs are demanding much higher throughput, so lasers should be capable of operating at PRFs much higher than about 25 KHz, such as 50 KHz to 60 KHz or higher. In addition, many laser processing applications are improved by employing ultraviolet (“UV”) energy wavelengths, which are typically less than about 400 nm. Such UV wavelengths may be generated by subjecting an IR laser to a harmonic generation process that stimulates the second, third, or fourth harmonics of the IR laser. Unfortunately, due to the nature of the harmonic generation, the pulse-to-pulse energy levels of such UV lasers are particularly sensitive to time variations in PRF and laser pulse interval.
- U.S. Pat. No. 6,172,325 for LASER PROCESSING POWER OUTPUT STABILIZATION APPARATUS AND METHOD EMPLOYING PROCESSING POSITION FEEDBACK, which is also assigned to the assignee of this patent application, describes a technique of operating the laser at a constant high repetition rate in conjunction with a position feedback-controlled laser pulse picking or gating device to provide laser pulse picking on demand at a random time interval that is a multiple of the laser pulse interval. This technique affords good laser pulse energy stability and high throughput.
- A typical laser pulse picking or gating device is an acousto-optic modulator (“AOM”) or electro-optic modulator (“EOM”, also referred to as a Pockels cell). Typical EOM material such as KD*P or KDP suffers from relatively strong absorption at the UV wavelengths, which results in a lower damage threshold of the material at the wavelength used and local heating along the laser beam path within the device, causing changes of the half wave-plate voltage of the device. Another disadvantage of the EOM is its questionable ability to perform well at a repetition rate over 50 KHz.
- AOM material is, on the other hand, quite transparent to UV light of 250 nm up to IR light of 2,000 nm, which allows the AOM to perform well throughout typical laser wavelengths within the range. An AOM can also easily accommodate the desirable gating of pulses at a repetition rate of up to a few hundred KHz. One disadvantage of the AOM is its limited diffraction efficiency of about 75-90 percent.
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FIG. 1 shows a typicalprior art AOM 10 driven by a radio frequency (“RF”)driver 12 and employed for a laser pulse picking or gating application, andFIGS. 2A to 2D (collectively,FIG. 2 ) show corresponding prior art timing graphs for incominglaser pulses 14,AOM RF pulses 15, andAOM output pulses FIG. 2A shows constant repetitionrate laser pulses 14 a-14 k that are emitted by a laser (not shown) and propagated toAOM 10.FIG. 2B demonstrates two exemplary schemes for applyingRF pulses 15 toAOM 10 to select which ones oflaser pulses 14 a-14 k, occurring at corresponding time periods 22 a-22 k, are propagated toward a target. In a first scheme, asingle RF pulse 15 cde (shown in dashed lines) is extended to covertime periods 22 c-22 e corresponding tolaser pulses RF pulses respective time periods laser pulses FIGS. 2C and 2D show the respectivefirst order beam 20 and zeroorder beam 16 propagated fromAOM 10, as determined by the presence or absence ofRF pulses 15 applied toAOM 10. - Referring to
FIGS. 1 and 2 , AOM 10 is driven byRF driver 12. When noRF pulses 15 are applied toAOM 10, incominglaser pulses 14 pass throughAOM 10 substantially along their original beam path and exit asbeam 16, typically referred to as the zeroorder beam 16. WhenRF pulses 15 are applied toAOM 10, part of the energy of incominglaser pulses 14 is diffracted from the path of the zeroorder beam 16 to a path of afirst order beam 20. AOM 10 has a diffraction efficiency that is defined as the ratio of the laser energy infirst order beam 20 to the laser energy in incominglaser pulses 14. Eitherfirst order beam 20 or zeroorder beam 16 can be used as a working beam, depending on different application considerations. For simplicity,laser pulses 14 entering AOM 10 will hereafter be referred as “laser pulses” or “laser output,” and pulses delivered to the target, because they are picked by AOM 10, will be referred to as “working laser pulses” or “working laser output.” - When
first order beam 20 is used as the working beam, the energy of the working laser pulses can be dynamically controlled from 100 percent of its maximum value down to substantially zero, as the power of RF pulses 15 changes from their maximum power to substantially zero, respectively. Because the practical limited diffraction efficiency of an AOM under an allowed maximum RF power load is about 75 percent to 90 percent, the maximum energy value of the working laser pulses is about 75 percent to 90 percent of the energy value inlaser pulses 14. However, when zeroorder beam 16 is used as the working beam, the energy of the working laser pulses can be dynamically controlled from 100 percent of the maximum energy inlaser pulses 14 down to 15 percent to 20 percent of the maximum value, as the power of RF pulses 15 changes from substantially zero to its maximum power, respectively. For memory link processing, for example, when no working laser pulse is demanded, no leakage of system laser pulse energy is permitted, i.e., the working laser pulse energy should be zero, so firstorder laser beam 20 is preferably used as the working beam. - With reference again to
FIG. 2 ,RF pulses 15 are applied toAOM 10 at random time intervals and only when working laser pulses are demanded, in this case, at random integral multiples of the laser pulse interval. The random output of working laser pulses results in random variable thermal loading onAOM 10. Variable thermal loading causes geometric distortion and temperature gradients inAOM 10, which cause gradients in its refractive index. The consequences of thermal loading distort a laser beam passing throughAOM 10, resulting in deteriorated laser beam quality and instability in the laser beam path or poor beam positioning accuracy. These distortions could be corrected to some degree if they could be kept constant. However, when the system laser pulses are demanded randomly, such as in laser link processing, these distortions will have the same random nature and cannot be practically corrected. - Test results on an AOM device, such as a Model N23080-2-1.06-LTD, made by NEOS Technologies, Melbourne, Fla., showed that with only two watts of RF power, the laser beam pointing accuracy can deviate as much as one milliradian when the RF is applied on and off randomly to the AOM. This deviation is a few hundred times greater than the maximum deviation allowed for the typical memory link processing system. Laser beam quality distortion resulting from the random thermal loading on the
AOM 10 will also deteriorate the focusability of the laser beam, resulting in a larger laser beam spot size at the focusing point. For applications such as the memory link processing that require the laser beam spot size to be as small as possible, this distortion is very undesirable. - What is needed, therefore, is an apparatus and a method for randomly picking working laser pulses from a high repetition rate laser pulse train without causing distortion of the laser beam and adversely affecting positioning accuracy caused by random thermal loading variation on the AOM. What is also needed is an apparatus and a method of generating working laser pulses having constant laser energy per pulse and constant pulse width on demand and/or on-the-fly at a high PRF and with high accuracy at different pulse time intervals for variety of laser applications such as laser link processing on memory chips. Moreover, what is needed is an efficient, high-throughput apparatus and method for utilizing the working laser pulses.
- An object of this invention is, therefore, to provide an apparatus and a method for picking laser pulses on demand from a high repetition rate pulsed laser.
- The following are several of the advantages of the invention. Embodiments of this invention perform such pulse picking with minimal thermal loading variation on the AOM to minimize distortion of the laser beam and positioning accuracy. They include an apparatus and a method for generating system on demand laser pulses having stable pulse energies and stable pulse widths at selected wavelengths from the UV to near IR and at high PRFs for high-accuracy laser processing applications, such as memory link severing. The embodiments of this invention provide an efficient, high-throughput apparatus and method for utilizing the working laser pulses.
- A workpiece processing system of this invention employs a laser coupled to a beam switching device that causes a laser beam or laser pulses to switch between first and second beam positioning heads such that when the first beam positioning head directs the laser beam to process a first workpiece, the second beam positioning head moves to a next target location on a second workpiece or a second set of locations on the first workpiece. When the first beam positioning head completes processing of the first workpiece and the second beam positioning head reaches its target position, the beam switching device causes the beam to switch to the second beam positioning head and then the second beam positioning head directs the laser beam to target locations on the second workpiece while the first beam positioning head moves to its next target position.
- An advantage of the present laser beam switching system is that the first and second workpieces receive almost the full power of the laser beam for processing. The total time utilization of the laser beam is increased by almost a factor of two, depending on the processing-to-moving time ratio. This greatly increases system throughput without significantly increasing system cost.
- A preferred beam switching device includes first and second AOMs that are positioned adjacent to each other so that the laser beam (or laser pulses) normally pass undeflected through the AOMs and terminate on a beam blocker. When RF energy is applied to the first AOM, about 90 percent of the laser beam is diffracted as a first laser beam and 10 percent remains as a residual laser beam that terminates in the beam blocker. Likewise, when RF energy is applied to the second AOM, about 90 percent of the laser beam is diffracted as a second laser beam and 10 percent remains as a residual laser beam that terminates in the beam blocker. In this embodiment, the laser generating the laser beam is constantly running at its desired pulse repetition rate.
- Employing the beam switching device is advantageous because constant operation of the laser eliminates thermal drifting of the laser output. Moreover, by operating the first and second AOMs with pulse picking methods of this invention, thermal loading variations in the AOMs will be minimized, thereby increasing laser beam positioning accuracy.
- Another advantage of employing the first and second AOMs as a beam switching device is that they can operate as a laser power control device, eliminating a need for a separate laser power controller in a typical laser-based workpiece processing system. Power control is possible because the response times of the AOMs are sufficiently fast for programming laser pulse amplitudes of the switched laser beam during processing of individual target locations on the workpieces. A typical laser processing application is blind via formation in etched-circuit boards, in which it is often necessary to reduce the laser pulse energy when the laser beam reaches the bottom of the via being formed.
- Additional aspects and advantages of this invention will be apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings.
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FIG. 1 is a simplified schematic view of a prior art AOM device and an RF driver, transmitting a zero order beam, a first order beam, or both of them. -
FIGS. 2A-2D are corresponding prior art timing graphs of, respectively, laser pulses, RF pulses, and first and zero order AOM output laser pulses. -
FIGS. 3A-3C are corresponding exemplary timing graphs of, respectively, laser outputs, RF pulses, and working laser outputs as employed in a preferred embodiment. -
FIGS. 4A-4C are alternative corresponding exemplary timing graphs of, respectively, laser outputs, RF pulses, and working laser outputs that demonstrate the use of the AOM for energy control of the working laser outputs. -
FIG. 5 is a simplified schematic block diagram of a laser beam switching system of this invention. -
FIG. 6 is a waveform timing diagram representing operational timing relationships among various components of the laser beam switching system ofFIG. 5 . -
FIG. 7 is a simplified schematic block diagram representing a preferred dual AOM laser beam switching device for use with this invention. -
FIG. 8 is a waveform timing diagram representing operational timing relationships among various components of a laser beam switching system employing the dual AOM switching device ofFIG. 7 . -
FIG. 9 is a simplified schematic block diagram of a typical workpiece processing system employing the laser beam switching device ofFIG. 7 . -
FIG. 10 is a waveform timing diagram representing operational timing relationships among various components of the workpiece processing system ofFIG. 9 . -
FIGS. 11A and 11B are simplified block diagrams representing workpiece processing systems of this invention employing a common optical processing path for multiple laser beams propagating from one and two laser sources, respectively. -
FIG. 12 is a simplified schematic block diagram representing an alternative workpiece processing system of this invention employing a fast EOM and a polarizing beam splitter to implement a laser beam switching device of this invention. -
FIG. 13 is a simplified pictorial block diagram representing an alternative laser beam switching system employing a fast steering mirror for switching a laser beam along alternate first and second pathways. - Thermal loading variations in AOMs, such as
prior art AOM 10, can be mitigated by employing pulse picking and laser power control methods shown with reference toFIGS. 3A-3C and 4A4C, respectively.FIGS. 3A-3C (collectively,FIG. 3 ) show corresponding timing graphs of laser outputs 24 a-24 k (collectively, laser outputs 24),RF pulses 38 a-38 k (collectively, RF pulses 38) applied toprior art AOM 10, and workinglaser outputs FIG. 3A shows laser outputs 24 a-24 k that are emitted by a laser (not shown) at a constant repetition rate and separated by substantially identicallaser output intervals 41. In typical embodiments, the laser output repetition rate may range from about 1 KHz up to about 500 KHz. Exemplary laser output repetition rates range from about 25 KHz to greater than about 100 KHz. For link processing embodiments, each of working laser outputs 40 preferably includes a single laser pulse having a multiple nanosecond pulse width. However, skilled persons will recognize that each of working laser outputs 40 may include a burst of one or more laser pulses, such as disclosed in U.S. Pat. No. 6,574,250 for LASER SYSTEM AND METHOD FOR PROCESSING A MEMORY LINK WITH A BURST OF LASER PULSES HAVING ULTRASHORT PULSE WIDTHS, which is assigned to assignee of this patent application, -or bursts of one or more pulses having pulse widths ranging from about 10 picoseconds to about 1,000 picoseconds. -
FIG. 3B shows a preferred RF pulse picking scheme employingRF pulses 38 having pulse durations, such as 42 a and 42 b (collectively, RF pulse durations 42) separated byRF pulse intervals 43 a-43 j (collectively, RF pulse intervals 43) that are substantially regular or uniform to keep thermal loading variations onAOM 10 within a preassigned operational tolerance. Such tolerance may be a specific thermal load window, but the preassigned tolerance may also or alternatively be windows of spot size or beam position accuracy. In one embodiment, the thermal loading variation is maintained within 5 percent and/or the beam pointing accuracy is maintained within 0.005 milliradian. In a preferred embodiment, at least one ofRF pulses 38 is generated to correspond with each of laser outputs 24. - Whenever one of working laser outputs 40 is demanded to impinge on a target such as an electrically conductive link, one of
RF pulses 38 is applied toAOM 10 in coincidence with one of laser outputs 24 such that it is transmitted throughAOM 10 and becomes the demanded one of working laser outputs 40. - In
FIG. 3B , thecoincident RF pulses 38 areRF pulses FIG. 3C shows the resulting corresponding workinglaser outputs RF pulses 38 are applied toAOM 10 in noncoincidence with corresponding ones of laser outputs 24. InFIG. 3B , thenoncoincident RF pulses 38 areRF pulses FIG. 3C shows that no working laser outputs 40 correspond withnoncoincident RF pulses 38. - The
noncoincident RF pulses 38 are preferably offset from the initiations of respective laser outputs 24 by time offsets 44 that are longer than about 0.5 microsecond. Skilled persons will appreciate that while time offsets 44 are shown to follow laser outputs 24, time offsets 44 could alternatively precede laser outputs 24 by a sufficient time to prevent targeting of laser working outputs 40. Thus,RF pulse intervals 43 surrounding one ofnoncoincident RF pulses 38 may be shorter (such asRF pulse intervals RF pulse intervals RF pulse intervals 43. - With reference again to
FIG. 3C ,nonimpingement intervals laser outputs laser outputs laser output interval 41. Thenonimpingement intervals laser outputs laser outputs laser output interval 41. - Skilled persons will appreciate that even though working laser outputs 40 are preferably
first order beam 20 for most applications, such as link processing, working laser outputs 40 may be zeroorder beam 16 where leakage is tolerable and higher working laser output power is desirable. - In a preferred embodiment, the coincident and
noncoincident RF pulses 38 not only employ about the same RF energy, which is the product of an RF power value and an RF duration, but also employ about the same RF power value and about the same RF duration. -
FIGS. 4A-4C (collectively,FIG. 4 ) show corresponding timing graphs of laser outputs 24,RF pulses 38 applied toAOM 10, and working laser outputs 40 that demonstrate howAOM 10 can be additionally employed to control the output power of working laser outputs 40.FIG. 4A is identical toFIG. 3A and is shown for convenience only.FIGS. 4B and 4C showRF pulses 38′ and working laser outputs 40′, with thecorresponding RF pulses 38 and working laser outputs 40 shown superimposed on them in dashed lines for convenience. The energy values of working laser outputs 40′ are attenuated by applying less RF power toAOM 10 forRF pulses 38′ than forRF pulses 38; however, theRF pulse durations 42′ are increased forRF pulses 38′ over theRF durations 42 employed forRF pulses 38 to maintain a substantially constant product of RF power value and RF duration in order to maintain substantially constant thermal loading onAOM 10. This technique permits on-demand selection for a continuum of output powers between working laser outputs 40 or 40′ without substantial variance in thermal loading onAOM 10. Skilled persons will appreciate that the RF power values andRF durations 42 of thenoncoincident RF pulses 38 can be kept as original or can be altered to be within a specified tolerance of the RF loading variation of thecoincident RF pulses 38′. -
RF pulse duration 42′ is preferably selected from about one microsecond to about one-half oflaser output interval 41, more preferably shorter than 30 percent oflaser output interval 41. For example, if the laser repetition rate is 50 KHz andlaser output interval 41 is 20 microseconds,RF pulse duration 42′ can be anywhere between one microsecond and ten microseconds. The minimumRF pulse duration AOM 10. It is preferable to initiate corresponding ones ofRF pulses RF pulses - It will be appreciated that the RF power of
RF pulses 38 applied toAOM 10 can be adjusted to control the energy of working laser outputs 40 and 40′ to meet target processing needs, whileRF pulse durations RF pulses RF pulses - The above-described techniques for employing an AOM in a workpiece processing application address beam steering accuracy and process window requirements, but do not address workpiece processing throughput and efficiency concerns. Employing a single laser for workpiece processing is time-inefficient because significant time and laser power is wasted while moving the laser output and workpiece target location relative to one another. Using a laser beam for an application, such as etched-circuit board via formation, typically results in only 50 percent laser beam utilization time because of the time needed to move the beam between target locations. Beam splitting does not correct this low time utilization problem. Prior workers have employed multiple laser beams to improve processing throughput, but the additional cost and wasted laser power is still a concern.
- This invention provides apparatus and methods for improving the throughput and efficiency of a single laser workpiece processing system. In this invention, AOMs employing pulse picking techniques are used in combination with a laser beam switching, or multiplexing, technique to improve workpiece processing and efficiency.
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FIGS. 5 and 6 represent a laserbeam switching system 50 and associated timing aspects of this invention in which a laser emitslaser pulses 54 that are reflected by anoptional fold mirror 56 to abeam switching device 58.Beam switching device 58 causeslaser pulses 54 to switch between first and second beam positioning heads 60 and 62 such that when firstbeam positioning head 60 is causinglaser pulses 54 to process a target location on afirst workpiece 64, secondbeam positioning head 62 is moving to a target location on asecond workpiece 66.Laser pulses 54 are directed frombeam switching device 58 tobeam positioning head 62 by anoptional fold mirror 68. When firstbeam positioning head 60 completes processing ofworkpiece 64, either an optional shutter (not shown), such as a Q-switch, turnslaser 52 off, as shown inFIG. 6 , orlaser pulses 54 are dumped. to a beam blocker (not shown). When secondbeam positioning head 62 reaches its target position,laser pulses 54 are switched on by the shutter and secondbeam positioning head 62 directslaser pulses 54 to target locations onworkpiece 66 while firstbeam positioning head 60 moves to its next target position.FIG. 6 represents workpiece processing times as intervals P and positioner move times between target positions as intervals M. - An advantage of laser
beam switching system 50 is that first andsecond workpieces laser pulses 54 for processing. The total time utilization oflaser pulses 54 is increased by almost a factor of two, depending on the processing-to-moving time ratio. This greatly increases system throughput without significantly increasing system cost. -
FIGS. 7 and 8 show a preferredbeam switching device 70 and related timing relationships.Beam switching device 70 includes first and second AOMs 72 and 74 positioned in optical series relation so that a laser beam orlaser pulses 76 normally pass undeflected throughAOMs laser beam 76A on abeam blocker 78. However, when afirst RF driver 80 applies about 6 Watts of 85 MHz RF signal tofirst AOM 72, about 90 percent oflaser beam 76 is diffracted aslaser beam laser beam 76A. Likewise, when asecond RF driver 82 applies about 6 Watts of 85 MHz RF signal tosecond AOM 74, about 90 percent oflaser beam 76 is diffracted aslaser beam laser beam 76A. In this embodiment, the laser generatinglaser beam 76 is constantly running at its desired pulse repetition rate. - When employing
beam switching device 70, no shutter or Q-switch is needed if time intervals are required when switching betweenlaser beams laser beam 76 onbeam blocker 78. -
Beam switching device 70 is advantageous because constant operation of the laser eliminates thermal drifting of the laser output. Moreover, by operating AOMs 72 and 74 with the pulse picking methods described with reference toFIGS. 3 and 4 , thermal loading variations will be minimized, thereby increasing laser beam positioning accuracy. Each of first and second AOMs 72 and 74 is preferably a Model N30085, manufactured by NEOS Technologies, Inc., of Melbourne, Florida. The N30085 AOM has a specified 90 percent diffraction efficiency when driven with two Watts of 85 MHz RF power. - Another advantage of
beam switching device 70 is that it can operate as a laser power control device, eliminating a need for a separate laser power controller in a typical laser-based workpiece processing system. Power control is possible because the response times ofAOMs laser beams -
FIGS. 9 and 10 show, respectively, a typicalworkpiece processing system 90 employingbeam switching device 70 and related operational timing relationships. Alaser 92 and avariable beam expander 94 cooperate to producelaser beam 76 that propagates throughbeam switching device 70, which operates as described with reference toFIGS. 7 and 8 to producelaser beams Laser beam 76A terminates inbeam blocker 78.Laser beam 76B is reflected by anoptional fold mirror 96 and directed by afirst XY scanner 98 to targetlocations first workpiece 100. Likewise,laser beam 76C is reflected by anoptional fold mirror 102 and directed by asecond XY scanner 104 to targetlocations second workpiece 106. First andsecond XY scanners second workpieces Y positioning stage 112. Skilled workers will understand that the scanners and workpieces are mounted on a split axis configured positioner system but that planar and stacked configurations may alternatively be employed. Skilled workers will also understand that the target locations on the first and second workpieces may be on a common substrate and/or may not share corresponding target locations. -
FIG. 10 showslaser beam 76B processing (drilling) target location 1 onworkpiece 100 whilesecond XY scanner 104 is moving the position oflaser beam 76C to target location 1 onworkpiece 106. Whenlaser beam 76C is processing target location 1 onworkpiece 106,first XY scanner 98 is moving the position oflaser beam 76B to targetlocation 2 onworkpiece 100. This process continues fortarget locations workpiece 106 is complete, at which time first and second X positioning stages 108 and 110 andY positioning stage 112 execute a long move to position first andsecond XY scanners target locations respective workpieces -
FIG. 11 A shows aworkpiece processing system 120 of this invention that employs a common modular imagedoptics assembly 122 andvariable beam expander 94 for optically processing bothlaser beams laser 92 and an optional fixedbeam expander 124 cooperate to producelaser beam 76 that propagates throughbeam switching device 70, which operates as described with reference toFIGS. 7 and 8 to producelaser beams Laser beams first turn mirror 126 directslaser beam 76B through a half-wave plate 128, which changes the polarization state oflaser beam 76B by 90 degrees relative to the polarization state oflaser beam 76C. The 90 degree phase-displacedlaser beam 76B is directed by asecond turn mirror 130 to apolarizing beam combiner 132.Laser beam 76C is directed by athird turn mirror 134 topolarizing beam combiner 132, which combines into a common propagation path portion the separate path portions along whichlaser beams Laser beams common laser beam 76D, which propagates along the common path portion through imagedoptics assembly 122 and optionalvariable expander 94 and into apolarizing beam splitter 136. Secondpolarizing beam splitter 136 separatescommon laser beam 76D intolaser beams Laser beam 76B is directed by afourth turn mirror 138 into, for example,first XY scanner 98; andlaser beam 76C is directed into, for example,second XY scanner 104. -
Beam expander 124 sets the shape oflaser beams Imaged optics assembly 122 shapes the Gaussian spatial distribution oflasers XY scanners -
FIG. 11B shows an alternativeworkpiece processing system 120′, in whichbeam switching device 70 is removed andlaser beams separate laser sources laser beam 76B is set by abeam expander 124 b, and the size oflaser beam 76C is set by abeam expander 124 c. The use ofseparate laser sources FIG. 11B . - Each of
workpiece processing systems workpiece processing system 120, employingbeam switching device 70 permits implementation with smaller optical components because switching is accomplished with a smaller beam width than that which would be found with downstream switching components. -
FIG. 12 shows another alternativeworkpiece processing system 140 of this invention employing afast EOM 142 and apolarizing beam splitter 144 to implement switching of alaser beam 146 between first and second XY beam scanning heads 98 and 104. Inworkpiece processing system 140,laser 92 emitslaser beam 146, which propagates through and is optically processed by anoptics module 148 and alaser power controller 150.Laser beam 146 exitslaser power controller 150 and entersfast EOM 142, which alternately polarizeslaser beam 146 into respective unrotated-polarization and rotated-polarization laser beams Polarizing beam splitter 144 receivesunrotated laser beam 146U and directs it to aturn mirror 152 to firstXY scanning head 98.Polarizing beam splitter 144 receives rotatedlaser beam 146R and directs it to secondXY scanning head 104. - A disadvantage of
workpiece processing system 140 is that current practical EOMs are limited in laser pulse repetition rates and are unable to withstand high amounts of ultraviolet laser beam power. Another limitation is that dumping unneeded laser beam energy requires shuttering or turning offlaser 92, such as by a Q-switch positioned inside the cavity oflaser 92. - On the other hand,
workpiece processing system 140 is advantageous because it is simpler than the dual AOMbeam switching device 70 described with reference toFIG. 7 and has a high extinguishing ratio that allows practically all of the power inlaser beam 146 to impinge on target locations aslaser beams -
FIG. 13 shows an alternative embodiment of a laserbeam switching system 210 in which alaser 212 emits alaser beam 214 that is deflected by a fast steering mirror (“FSM”) 216 along alternate first andsecond paths FSM 216 preferably employs a mirror having a deflection angle that is controlled by materials that translate voltages into angular displacements.FSM 216 operates similar to a galvanometer driven rotating mirror but at angular speeds up to 10 times faster than galvanometers and over anangular deflection range 222 of up to about 5 milliradians. Deflecting a typical laser beam diameter with such a limited angular deflection range requires apath length 224 that is sufficiently long, preferably about one meter, to separate first andsecond beam paths sufficient distance 226, preferably about 10 millimeters, for inserting between them an HR coatedright angle prism 228 that further separates and directs first andsecond beams baths Switching laser beam 214 at a location where it is smallest in diameter, such as before any beam expander, would minimizepath length 224 required to sufficiently separate first andsecond paths right angle prism 228. -
FSM 216 may be a two-axis device that could further provide switching oflaser beam 214 to more than two positions. For example,laser beam 214 could be directed to a beam blocker during long moves as described with reference toFIGS. 9 and 10 to maintain constant thermal conditions inlaser 212 and minimize duty cycle related laser beam power stability problems. - Laser
beam switching system 210 allows implementing a single laser workpiece processing system having the same workpiece processing throughput as a two laser system, provided the move times are over 3 ms and the workpiece processing time and laser beam switching time are less than 1.0 ms. - Laser
beam switching system 210 is advantageous because the use of a single laser and associated optics reduces cost by 20 percent to 40 percent, depending on the type of laser required, as compared with a two laser system. - Skilled workers will recognize that portions of this invention may be implemented differently from the implementations described above for preferred embodiments. For example, galvonometer and rotating mirror devices may also be used as laser beam switching devices; IR, visible, and UV lasers may be employed; target locations may be on single or multiple workpieces; laser beam switching may be effected to more than two or three beam paths; multiple lasers may be employed and each of their respective laser outputs switched among multiple paths; AOMs may be switched by single or multiple RF sources; and the scanning heads employed may further include galvanometers, FSMs, and other than XY coordinate positioning techniques.
- It will be obvious to skilled workers that many other changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. The scope of the present invention should, therefore, be determined only by the following claims.
Claims (6)
1. A system configured to direct a laser beam selectively in multiple beam propagation directions in a coordinated manner to achieve high-speed processing of material in different regions of a target specimen, comprising:
a laser source emitting a laser beam that includes a series of laser pulses;
a beam switching device receiving the series of laser pulses and, in response to a beam switching signal, directing first and second groups of the laser beam pulses to propagate along respective first and second beam axes;
a first positioning mechanism responding to a first control signal to provide relative movement of the first beam axis and the target specimen to selectively position the first beam axis at different first target regions of the target specimen and to process material in the first target regions of the target specimen;
a second positioning mechanism responding to a second control signal to provide relative movement of the second beam axis and the target specimen to selectively position the second beam axis at different second target regions of the target specimen to process material in the second target regions of the target specimen;
a controller producing the beam switching signal and the first and second control signals to effect coordinated system operation in first and second operational sequences;
the first operational sequence including the beam switching device directing the first group of laser beam pulses for incidence on a selected one of the first target regions, the first positioning mechanism providing the relative movement to enable the first group of laser pulses to process material in the selected first target region, and, during the material processing by the first group of laser pulses, the second positioning mechanism providing the relative movement to position the second beam axis to a selected one of the second target regions; and
the second operational sequence including the beam switching device directing the second group of laser beam pulses for incidence on the selected second target region, the second positioning mechanism providing the relative movement to enable the second group of laser pulses to process material in the selected second target region, and, during the material processing by the second group of laser pulses, the first positioning mechanism providing the relative movement to position the first beam axis from the selected first target region to a next selected one of the first target regions.
2. A beam switching device that receives a laser beam and provides beam outputs that propagate selectively along different beam axes, comprising:
a controller producing a control drive signal in first and second states;
first and second optically associated acousto-optic modulators, the first acousto-optic modulator receiving an incoming laser beam, and the first and second acousto-optic modulators cooperating in response to the first and second states of the control device signal to produce respective first and second laser beam outputs propagating from the second acousto-optic modulator; and
the first laser beam output including a major component propagating along a first beam axis and a minor component propagating along a first minor component axis, and the second laser output including a major component propagating along a second beam axis that is angularly offset from the first beam axis and a minor component propagating along a second minor component axis that is substantially coincident to the first minor component axis.
3. The beam switching device of claim 2 , further comprising a beam blocker positioned to terminate the minor components propagating along the first and second minor component axes.
4. The beam switching device of claim 2 , in which:
the controller includes first and second RF drivers that are operationally associated with the respective first and second acousto-optic modulators; and
in the first state of the control drive signal, the first, RF driver causes the first acousto-optic modulator to pass the incoming laser beam as an undeflected beam incident on the second acousto-optic modulator and the second RF driver causes the second acousto-optic modulator to diffract the incident undeflected beam to form the major component to propagating along the first beam axis and the minor component propagating along the first minor component axis.
5. The beam switching device of claim 2 , in which:
the controller includes first and second RF drivers that are operationally associated with the respective first and second acousto-optic modulators; and
in the second state of the control drive signal, the second RF driver causes the second acousto-optic modulator to pass incident light as an undeflected beam and the first RF driver causes the first acousto-optic modulator to diffract the incoming laser beam to form the major component propagating along the second beam axis and the minor component to propagating along the second minor component axis.
6. The beam switching device of claim 2 , in which the first and second optically associated acousto-optic modulators are positioned in optical series.
Priority Applications (8)
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US11/000,333 US20050224469A1 (en) | 2003-06-30 | 2004-11-29 | Efficient micro-machining apparatus and method employing multiple laser beams |
PCT/US2005/043112 WO2006062766A2 (en) | 2004-11-29 | 2005-11-29 | Efficient micro-machining apparatus and method employing multiple laser beams |
TW094141899A TW200628255A (en) | 2004-11-29 | 2005-11-29 | Efficient micro-machining apparatus and method employing multiple laser beams |
KR1020077012149A KR20070085548A (en) | 2004-11-29 | 2005-11-29 | Efficient micro-machining apparatus and method employing multiple laser beams |
DE112005003088T DE112005003088T5 (en) | 2004-11-29 | 2005-11-29 | Efficient micromachining device and method using multiple laser beams |
JP2007543590A JP2008521615A (en) | 2004-11-29 | 2005-11-29 | Apparatus and method for efficient microfabrication using multiple laser beams |
US11/720,256 US20100193481A1 (en) | 2004-11-29 | 2005-11-29 | Laser constructed with multiple output couplers to generate multiple output beams |
GB0710285A GB2434560A (en) | 2004-11-29 | 2007-05-30 | Efficient micro-machining apparatus and method for employing multiple laser beams |
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US11/000,333 US20050224469A1 (en) | 2003-06-30 | 2004-11-29 | Efficient micro-machining apparatus and method employing multiple laser beams |
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US11/000,330 Continuation-In-Part US20060114948A1 (en) | 2004-11-29 | 2004-11-29 | Workpiece processing system using a common imaged optical assembly to shape the spatial distributions of light energy of multiple laser beams |
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US11/000,333 Abandoned US20050224469A1 (en) | 2003-06-30 | 2004-11-29 | Efficient micro-machining apparatus and method employing multiple laser beams |
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US20060114948A1 (en) * | 2004-11-29 | 2006-06-01 | Lo Ho W | Workpiece processing system using a common imaged optical assembly to shape the spatial distributions of light energy of multiple laser beams |
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Citations (87)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4083629A (en) * | 1976-11-29 | 1978-04-11 | Gte Laboratories Incorporated | Beam splitting system for a welding laser |
US4295741A (en) * | 1979-08-30 | 1981-10-20 | United Technologies Corporation | Two-wavelength phase control system |
US4547855A (en) * | 1982-09-01 | 1985-10-15 | Westinghouse Electric Corp. | Plural computer control for shared laser machining |
US4564739A (en) * | 1983-09-15 | 1986-01-14 | Siemens Aktiengesellschaft | Apparatus for labeling parts with a laser |
US4701591A (en) * | 1983-11-07 | 1987-10-20 | Matsushita Electric Industrial Co., Ltd | Apparatus for processing multiple workpieces utilizing a single laser beam source |
US4732473A (en) * | 1984-06-14 | 1988-03-22 | Josef Bille | Apparatus for, and methods of, determining the characteristics of semi-conductor wafers |
US4945489A (en) * | 1988-05-25 | 1990-07-31 | Robolase Systems, Inc. | Laser time-sharing system |
US4982166A (en) * | 1989-03-01 | 1991-01-01 | Morrow Clifford E | Method and apparatus for combining two lower power laser beams to produce a combined higher power beam |
US5018163A (en) * | 1990-04-26 | 1991-05-21 | The United States Of America As Represented By The Secretary Of The Army | Gatling gun laser pulse amplifier using an optical diode |
US5109149A (en) * | 1990-03-15 | 1992-04-28 | Albert Leung | Laser, direct-write integrated circuit production system |
US5226051A (en) * | 1991-06-04 | 1993-07-06 | Lightwave Electronics | Laser pump control for output power stabilization |
US5265114A (en) * | 1992-09-10 | 1993-11-23 | Electro Scientific Industries, Inc. | System and method for selectively laser processing a target structure of one or more materials of a multimaterial, multilayer device |
US5268911A (en) * | 1991-07-10 | 1993-12-07 | Young Eddie H | X-cut crystal quartz acousto-optic modulator |
US5293389A (en) * | 1990-09-19 | 1994-03-08 | Hitachi, Ltd. | Multi-pulse laser beam generation method and device and laser beam machining method and apparatus using multi-pulse laser beam |
US5302798A (en) * | 1991-04-01 | 1994-04-12 | Canon Kabushiki Kaisha | Method of forming a hole with a laser and an apparatus for forming a hole with a laser |
US5315604A (en) * | 1993-01-28 | 1994-05-24 | International Business Machines Corporation | Optical structure for adjusting the peak power of a laser beam |
US5590141A (en) * | 1992-04-24 | 1996-12-31 | Electro Scientific Industries, Inc. | Method and apparatus for generating and employing a high density of excited ions in a lasant |
US5676866A (en) * | 1994-01-01 | 1997-10-14 | Carl-Zeiss Stiftung | Apparatus for laser machining with a plurality of beams |
US5748317A (en) * | 1997-01-21 | 1998-05-05 | Brown University Research Foundation | Apparatus and method for characterizing thin film and interfaces using an optical heat generator and detector |
US5781585A (en) * | 1994-04-11 | 1998-07-14 | Daimler Benz Aktiengesellschaft | Arrangement for monitoring a two-wire bus line |
US5822355A (en) * | 1995-12-21 | 1998-10-13 | Electronics And Telecommunications Research Institute | Dual cavity laser |
US5856648A (en) * | 1995-05-03 | 1999-01-05 | Mdc Max Datwyler Bleienbach Ag | Method and apparatus for producing wells in the surface of a rotogravure cyclinder with a laser |
US5897796A (en) * | 1997-06-16 | 1999-04-27 | Chrysler Corporation | Method and apparatus for in-situ laser welding of hemmed joints |
US5910262A (en) * | 1997-02-06 | 1999-06-08 | International Business Machines Corporation | Method and tool for laser texturing of glass substrates |
US5917843A (en) * | 1993-12-24 | 1999-06-29 | Electro Optic Systems Pty. | Laser cavity assembly |
US5948291A (en) * | 1997-04-29 | 1999-09-07 | General Scanning, Inc. | Laser beam distributor and computer program for controlling the same |
US5981903A (en) * | 1997-03-28 | 1999-11-09 | International Business Machines Corporation | Laser system for simultaneous texturing of two sides of a substrate |
US5998759A (en) * | 1996-12-24 | 1999-12-07 | General Scanning, Inc. | Laser processing |
US6034349A (en) * | 1997-05-28 | 2000-03-07 | Komatsu Ltd. | Laser machining system for sequential irradiation of machining points |
US6037564A (en) * | 1998-03-31 | 2000-03-14 | Matsushita Electric Industrial Co., Ltd. | Method for scanning a beam and an apparatus therefor |
US6058132A (en) * | 1997-05-15 | 2000-05-02 | Sumitomo Heavy Industries, Ltd. | Laser beam machining apparatus using a plurality of galvanoscanners |
US6059555A (en) * | 1996-09-04 | 2000-05-09 | International Business Machines Corporation | Optical apparatus for dual-beam laser texturing |
US6087625A (en) * | 1997-03-21 | 2000-07-11 | Sumitomo Heavy Industries, Ltd. | Laser machining apparatus |
US6114654A (en) * | 1996-06-07 | 2000-09-05 | Canon Kabushiki Kaisha | Split-beam laser apparatus for making a nozzle member |
US6172325B1 (en) * | 1999-02-10 | 2001-01-09 | Electro Scientific Industries, Inc. | Laser processing power output stabilization apparatus and method employing processing position feedback |
US6180913B1 (en) * | 1996-08-23 | 2001-01-30 | Carl Baasel Lasertechik Gmbh | Multi-head laser engraving machine |
US6239443B1 (en) * | 1997-03-19 | 2001-05-29 | Kabushiki Kaisha Toshiba | Apparatus for emitting a beam to a sample used for manufacturing a semiconducor device |
US6281471B1 (en) * | 1999-12-28 | 2001-08-28 | Gsi Lumonics, Inc. | Energy-efficient, laser-based method and system for processing target material |
US6291794B1 (en) * | 1999-10-19 | 2001-09-18 | Lsp Technologies, Inc. | Multiple beam time sharing for a laser shock peening apparatus |
US6292303B1 (en) * | 1999-03-10 | 2001-09-18 | Hamar Laser Instruments, Inc. | Laser apparatus for simultaneously generating a plurality of laser planes from a single laser source |
US6313433B1 (en) * | 2000-04-03 | 2001-11-06 | Universal Laser Systems, Inc | Laser material processing system with multiple laser sources apparatus and method |
US6324195B1 (en) * | 1999-01-13 | 2001-11-27 | Kaneka Corporation | Laser processing of a thin film |
US6335509B1 (en) * | 1998-10-02 | 2002-01-01 | Lg. Philips Lcd Co., Ltd. | Laser annealing apparatus |
US6339604B1 (en) * | 1998-06-12 | 2002-01-15 | General Scanning, Inc. | Pulse control in laser systems |
US6340806B1 (en) * | 1999-12-28 | 2002-01-22 | General Scanning Inc. | Energy-efficient method and system for processing target material using an amplified, wavelength-shifted pulse train |
US6356575B1 (en) * | 1999-07-06 | 2002-03-12 | Raytheon Company | Dual cavity multifunction laser system |
US6365061B1 (en) * | 1999-02-17 | 2002-04-02 | Imation Corp. | Multibeam laser servowriting of magnetic data storage media |
US20020050488A1 (en) * | 2000-03-01 | 2002-05-02 | Dmitri Nikitin | Method and apparatus for thermally processing quartz using a plurality of laser beams |
US6403920B1 (en) * | 1999-02-09 | 2002-06-11 | Matsushita Electric Industrial Co., Ltd. | Laser processing apparatus and method |
US6423925B1 (en) * | 2000-02-17 | 2002-07-23 | Universal Laser Systems, Inc. | Apparatus and method for combining multiple laser beams in laser material processing systems |
US6452132B1 (en) * | 1999-06-23 | 2002-09-17 | Sumitomo Electric Industries, Ltd. | Laser hole boring apparatus |
US6462306B1 (en) * | 1999-04-27 | 2002-10-08 | Gsi Lumonics, Inc. | System and method for material processing using multiple laser beams |
US20020167581A1 (en) * | 2001-03-29 | 2002-11-14 | Cordingley James J. | Methods and systems for thermal-based laser processing a multi-material device |
US6521866B1 (en) * | 1999-01-14 | 2003-02-18 | Hitachi Via Mechanics, Ltd. | Laser beam machining and laser beam machine |
US6531678B2 (en) * | 2000-10-11 | 2003-03-11 | Murata Manufacturing Co., Ltd. | Method for processing ceramic green sheet and laser beam machine used therefor |
US6531677B2 (en) * | 2000-10-06 | 2003-03-11 | Hitachi Via Mechanics, Ltd. | Method and apparatus for drilling printed wiring boards |
US6541731B2 (en) * | 2000-01-25 | 2003-04-01 | Aculight Corporation | Use of multiple laser sources for rapid, flexible machining and production of vias in multi-layered substrates |
US6563083B2 (en) * | 2000-12-18 | 2003-05-13 | Thyssen Laser-Technik Gmbh | Laser robot for workpiece machining and method for workpiece machining with a laser robot |
US6574250B2 (en) * | 2000-01-10 | 2003-06-03 | Electro Scientific Industries, Inc. | Laser system and method for processing a memory link with a burst of laser pulses having ultrashort pulse widths |
US6580055B2 (en) * | 2000-06-09 | 2003-06-17 | Sumitomo Heavy Industries, Ltd. | Laser processing apparatus and method |
US6605799B2 (en) * | 2000-05-25 | 2003-08-12 | Westar Photonics | Modulation of laser energy with a predefined pattern |
US20030151053A1 (en) * | 2000-01-10 | 2003-08-14 | Yunlong Sun | Processing a memory link with a set of at least two laser pulses |
US6608281B2 (en) * | 2000-08-10 | 2003-08-19 | Mitsubishi Heavy Industries, Ltd. | Laser beam machining head and laser beam machining apparatus having same |
US6625181B1 (en) * | 2000-10-23 | 2003-09-23 | U.C. Laser Ltd. | Method and apparatus for multi-beam laser machining |
US6635849B1 (en) * | 1999-03-05 | 2003-10-21 | Mitsubishi Denki Kabushiki Kaisha | Laser beam machine for micro-hole machining |
US6635850B2 (en) * | 1993-06-04 | 2003-10-21 | Seiko Epson Corporation | Laser machining method for precision machining |
US6664498B2 (en) * | 2001-12-04 | 2003-12-16 | General Atomics | Method and apparatus for increasing the material removal rate in laser machining |
US6697394B2 (en) * | 2000-02-10 | 2004-02-24 | Jenoptik Ldt Gmbh | Directly modulatable laser |
US6720519B2 (en) * | 2001-11-30 | 2004-04-13 | Matsushita Electric Industrial Co., Ltd. | System and method of laser drilling |
US6737635B2 (en) * | 2000-04-04 | 2004-05-18 | Leica Microsystems Heidelberg Gmbh | Apparatus for combining light and confocal scanning microscope |
US20040104208A1 (en) * | 2002-03-28 | 2004-06-03 | Kenichi Ijima | Laser machining apparatus |
US20040134896A1 (en) * | 1999-12-28 | 2004-07-15 | Bo Gu | Laser-based method and system for memory link processing with picosecond lasers |
US20040134894A1 (en) * | 1999-12-28 | 2004-07-15 | Bo Gu | Laser-based system for memory link processing with picosecond lasers |
US20040173590A1 (en) * | 2002-12-17 | 2004-09-09 | Hitachi Via Mechanics Ltd. | Multi-axis laser machine, method for machining with the same, and recording medium recording computer program for controlling the same |
US6838639B2 (en) * | 2000-02-15 | 2005-01-04 | Datacard Corporation | Method for the machining of workpieces by means of several laser beams |
US6849824B2 (en) * | 2002-12-26 | 2005-02-01 | Hitachi Via Mechanics, Ltd. | Multibeam laser drilling apparatus |
US6875951B2 (en) * | 2000-08-29 | 2005-04-05 | Mitsubishi Denki Kabushiki Kaisha | Laser machining device |
US6879605B2 (en) * | 2000-07-24 | 2005-04-12 | Laserfront Technologies, Inc. | Method and apparatus for performing pattern defect repair using Q-switched mode-locked pulse laser |
US6887804B2 (en) * | 2000-01-10 | 2005-05-03 | Electro Scientific Industries, Inc. | Passivation processing over a memory link |
US6909735B2 (en) * | 2003-04-10 | 2005-06-21 | Hitachi Via Mechanics, Ltd. | System and method for generating and controlling multiple independently steerable laser beam for material processing |
US6940888B2 (en) * | 2002-11-21 | 2005-09-06 | New Wave Research | Dual head laser system with intra-cavity polarization, and particle image velocimetry system using same |
US6951995B2 (en) * | 2002-03-27 | 2005-10-04 | Gsi Lumonics Corp. | Method and system for high-speed, precise micromachining an array of devices |
US20050254530A1 (en) * | 2004-05-14 | 2005-11-17 | Yunlong Sun | Multi-output harmonic laser and methods employing same |
US7006237B2 (en) * | 2002-03-26 | 2006-02-28 | Mitsubishi Denki Kabushiki Kaisha | Laser beam positioning device for laser processing equipment |
US7027199B2 (en) * | 2004-06-07 | 2006-04-11 | Electro Scientific Industries, Inc. | AOM modulation techniques for facilitating pulse-to-pulse energy stability in laser systems |
US20060114948A1 (en) * | 2004-11-29 | 2006-06-01 | Lo Ho W | Workpiece processing system using a common imaged optical assembly to shape the spatial distributions of light energy of multiple laser beams |
US20060128073A1 (en) * | 2004-12-09 | 2006-06-15 | Yunlong Sun | Multiple-wavelength laser micromachining of semiconductor devices |
Family Cites Families (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US167581A (en) * | 1875-09-07 | Improvement in pen-holders | ||
US185474A (en) * | 1876-12-19 | Improvement in ventilating apparatus for cars | ||
US47541A (en) * | 1865-05-02 | Improvement in mode of mounting drills | ||
US4930901A (en) | 1988-12-23 | 1990-06-05 | Electro Scientific Industries, Inc. | Method of and apparatus for modulating a laser beam |
JP2937361B2 (en) | 1989-09-29 | 1999-08-23 | 日本電気株式会社 | Laser processing machine |
US5509022A (en) * | 1991-09-20 | 1996-04-16 | The University Of Melbourne | Self-tuned mode-locked laser |
US5197074A (en) | 1991-12-26 | 1993-03-23 | Electro Scientific Industries, Inc. | Multi-function intra-resonator loss modulator and method of operating same |
US5347392A (en) * | 1992-02-26 | 1994-09-13 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Electric-optic resonant phase modulator |
US5390204A (en) * | 1992-09-25 | 1995-02-14 | Incisive Technologies, Inc. | Intracavity modulated pulsed laser with a variably controllable modulation frequency |
US5751585A (en) | 1995-03-20 | 1998-05-12 | Electro Scientific Industries, Inc. | High speed, high accuracy multi-stage tool positioning system |
US5574738A (en) * | 1995-06-07 | 1996-11-12 | Honeywell Inc. | Multi-gigahertz frequency-modulated vertical-cavity surface emitting laser |
US6057180A (en) | 1998-06-05 | 2000-05-02 | Electro Scientific Industries, Inc. | Method of severing electrically conductive links with ultraviolet laser output |
US6300590B1 (en) | 1998-12-16 | 2001-10-09 | General Scanning, Inc. | Laser processing |
JP2001272617A (en) * | 2000-03-28 | 2001-10-05 | Noritsu Koki Co Ltd | Laser beam scanning unit and photographic processing device |
US6527035B2 (en) | 2000-07-06 | 2003-03-04 | Overhead Door Corporation | Guide track assemblies and mounting brackets for upward acting doors |
CN1219319C (en) | 2000-07-12 | 2005-09-14 | 电子科学工业公司 | UV laser system and method for single pulse servering of IC fuses |
US6781090B2 (en) | 2001-03-12 | 2004-08-24 | Electro Scientific Industries, Inc. | Quasi-CW diode-pumped, solid-state harmonic laser system and method employing same |
TW528636B (en) | 2001-05-09 | 2003-04-21 | Electro Scient Ind Inc | Micromachining with high-energy, intra-cavity Q-switched CO2 laser pulses |
KR20040073958A (en) | 2001-12-17 | 2004-08-21 | 일렉트로 싸이언티픽 인더스트리이즈 인코포레이티드 | Processing a memory link with a set of at least two laser pulses |
-
2003
- 2003-06-30 US US10/611,798 patent/US6947454B2/en not_active Expired - Lifetime
-
2004
- 2004-05-05 WO PCT/US2004/014013 patent/WO2005006422A1/en active Application Filing
- 2004-05-05 JP JP2006518611A patent/JP4331752B2/en active Active
- 2004-05-05 KR KR1020057025274A patent/KR101123231B1/en active IP Right Grant
- 2004-05-05 DE DE112004001190T patent/DE112004001190T5/en not_active Ceased
- 2004-05-05 CN CN2004800184194A patent/CN1813339B/en active Active
- 2004-05-05 GB GB0601470A patent/GB2420004B/en not_active Expired - Fee Related
- 2004-05-05 CA CA002530688A patent/CA2530688A1/en not_active Abandoned
- 2004-05-10 TW TW093113052A patent/TWI348799B/en active
- 2004-11-29 US US11/000,333 patent/US20050224469A1/en not_active Abandoned
Patent Citations (95)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4083629A (en) * | 1976-11-29 | 1978-04-11 | Gte Laboratories Incorporated | Beam splitting system for a welding laser |
US4295741A (en) * | 1979-08-30 | 1981-10-20 | United Technologies Corporation | Two-wavelength phase control system |
US4547855A (en) * | 1982-09-01 | 1985-10-15 | Westinghouse Electric Corp. | Plural computer control for shared laser machining |
US4564739A (en) * | 1983-09-15 | 1986-01-14 | Siemens Aktiengesellschaft | Apparatus for labeling parts with a laser |
US4701591A (en) * | 1983-11-07 | 1987-10-20 | Matsushita Electric Industrial Co., Ltd | Apparatus for processing multiple workpieces utilizing a single laser beam source |
US4732473A (en) * | 1984-06-14 | 1988-03-22 | Josef Bille | Apparatus for, and methods of, determining the characteristics of semi-conductor wafers |
US4945489A (en) * | 1988-05-25 | 1990-07-31 | Robolase Systems, Inc. | Laser time-sharing system |
US4982166A (en) * | 1989-03-01 | 1991-01-01 | Morrow Clifford E | Method and apparatus for combining two lower power laser beams to produce a combined higher power beam |
US5109149A (en) * | 1990-03-15 | 1992-04-28 | Albert Leung | Laser, direct-write integrated circuit production system |
US5018163A (en) * | 1990-04-26 | 1991-05-21 | The United States Of America As Represented By The Secretary Of The Army | Gatling gun laser pulse amplifier using an optical diode |
US5293389A (en) * | 1990-09-19 | 1994-03-08 | Hitachi, Ltd. | Multi-pulse laser beam generation method and device and laser beam machining method and apparatus using multi-pulse laser beam |
US5302798A (en) * | 1991-04-01 | 1994-04-12 | Canon Kabushiki Kaisha | Method of forming a hole with a laser and an apparatus for forming a hole with a laser |
US5226051A (en) * | 1991-06-04 | 1993-07-06 | Lightwave Electronics | Laser pump control for output power stabilization |
US5268911A (en) * | 1991-07-10 | 1993-12-07 | Young Eddie H | X-cut crystal quartz acousto-optic modulator |
US5590141A (en) * | 1992-04-24 | 1996-12-31 | Electro Scientific Industries, Inc. | Method and apparatus for generating and employing a high density of excited ions in a lasant |
US5265114A (en) * | 1992-09-10 | 1993-11-23 | Electro Scientific Industries, Inc. | System and method for selectively laser processing a target structure of one or more materials of a multimaterial, multilayer device |
US5265114C1 (en) * | 1992-09-10 | 2001-08-21 | Electro Scient Ind Inc | System and method for selectively laser processing a target structure of one or more materials of a multimaterial multilayer device |
US5315604A (en) * | 1993-01-28 | 1994-05-24 | International Business Machines Corporation | Optical structure for adjusting the peak power of a laser beam |
US6635850B2 (en) * | 1993-06-04 | 2003-10-21 | Seiko Epson Corporation | Laser machining method for precision machining |
US5917843A (en) * | 1993-12-24 | 1999-06-29 | Electro Optic Systems Pty. | Laser cavity assembly |
US5676866A (en) * | 1994-01-01 | 1997-10-14 | Carl-Zeiss Stiftung | Apparatus for laser machining with a plurality of beams |
US5781585A (en) * | 1994-04-11 | 1998-07-14 | Daimler Benz Aktiengesellschaft | Arrangement for monitoring a two-wire bus line |
US5856648A (en) * | 1995-05-03 | 1999-01-05 | Mdc Max Datwyler Bleienbach Ag | Method and apparatus for producing wells in the surface of a rotogravure cyclinder with a laser |
US5822355A (en) * | 1995-12-21 | 1998-10-13 | Electronics And Telecommunications Research Institute | Dual cavity laser |
US6114654A (en) * | 1996-06-07 | 2000-09-05 | Canon Kabushiki Kaisha | Split-beam laser apparatus for making a nozzle member |
US6180913B1 (en) * | 1996-08-23 | 2001-01-30 | Carl Baasel Lasertechik Gmbh | Multi-head laser engraving machine |
US6059555A (en) * | 1996-09-04 | 2000-05-09 | International Business Machines Corporation | Optical apparatus for dual-beam laser texturing |
US5998759A (en) * | 1996-12-24 | 1999-12-07 | General Scanning, Inc. | Laser processing |
US5748317A (en) * | 1997-01-21 | 1998-05-05 | Brown University Research Foundation | Apparatus and method for characterizing thin film and interfaces using an optical heat generator and detector |
US5910262A (en) * | 1997-02-06 | 1999-06-08 | International Business Machines Corporation | Method and tool for laser texturing of glass substrates |
US6107599A (en) * | 1997-02-06 | 2000-08-22 | International Business Machines Corporation | Method and tool for laser texturing of glass substrates |
US6239443B1 (en) * | 1997-03-19 | 2001-05-29 | Kabushiki Kaisha Toshiba | Apparatus for emitting a beam to a sample used for manufacturing a semiconducor device |
US6087625A (en) * | 1997-03-21 | 2000-07-11 | Sumitomo Heavy Industries, Ltd. | Laser machining apparatus |
US5981903A (en) * | 1997-03-28 | 1999-11-09 | International Business Machines Corporation | Laser system for simultaneous texturing of two sides of a substrate |
US5948291A (en) * | 1997-04-29 | 1999-09-07 | General Scanning, Inc. | Laser beam distributor and computer program for controlling the same |
US6058132A (en) * | 1997-05-15 | 2000-05-02 | Sumitomo Heavy Industries, Ltd. | Laser beam machining apparatus using a plurality of galvanoscanners |
US6034349A (en) * | 1997-05-28 | 2000-03-07 | Komatsu Ltd. | Laser machining system for sequential irradiation of machining points |
US5897796A (en) * | 1997-06-16 | 1999-04-27 | Chrysler Corporation | Method and apparatus for in-situ laser welding of hemmed joints |
US6037564A (en) * | 1998-03-31 | 2000-03-14 | Matsushita Electric Industrial Co., Ltd. | Method for scanning a beam and an apparatus therefor |
US6339604B1 (en) * | 1998-06-12 | 2002-01-15 | General Scanning, Inc. | Pulse control in laser systems |
US6335509B1 (en) * | 1998-10-02 | 2002-01-01 | Lg. Philips Lcd Co., Ltd. | Laser annealing apparatus |
US6324195B1 (en) * | 1999-01-13 | 2001-11-27 | Kaneka Corporation | Laser processing of a thin film |
US6521866B1 (en) * | 1999-01-14 | 2003-02-18 | Hitachi Via Mechanics, Ltd. | Laser beam machining and laser beam machine |
US6403920B1 (en) * | 1999-02-09 | 2002-06-11 | Matsushita Electric Industrial Co., Ltd. | Laser processing apparatus and method |
US6172325B1 (en) * | 1999-02-10 | 2001-01-09 | Electro Scientific Industries, Inc. | Laser processing power output stabilization apparatus and method employing processing position feedback |
US6365061B1 (en) * | 1999-02-17 | 2002-04-02 | Imation Corp. | Multibeam laser servowriting of magnetic data storage media |
US6635849B1 (en) * | 1999-03-05 | 2003-10-21 | Mitsubishi Denki Kabushiki Kaisha | Laser beam machine for micro-hole machining |
US6292303B1 (en) * | 1999-03-10 | 2001-09-18 | Hamar Laser Instruments, Inc. | Laser apparatus for simultaneously generating a plurality of laser planes from a single laser source |
US6462306B1 (en) * | 1999-04-27 | 2002-10-08 | Gsi Lumonics, Inc. | System and method for material processing using multiple laser beams |
US6452132B1 (en) * | 1999-06-23 | 2002-09-17 | Sumitomo Electric Industries, Ltd. | Laser hole boring apparatus |
US6356575B1 (en) * | 1999-07-06 | 2002-03-12 | Raytheon Company | Dual cavity multifunction laser system |
US6291794B1 (en) * | 1999-10-19 | 2001-09-18 | Lsp Technologies, Inc. | Multiple beam time sharing for a laser shock peening apparatus |
US6486434B2 (en) * | 1999-10-19 | 2002-11-26 | Lsp Technologies, Inc. | Multiple beam time sharing for a laser shock peening apparatus |
US20040134894A1 (en) * | 1999-12-28 | 2004-07-15 | Bo Gu | Laser-based system for memory link processing with picosecond lasers |
US6281471B1 (en) * | 1999-12-28 | 2001-08-28 | Gsi Lumonics, Inc. | Energy-efficient, laser-based method and system for processing target material |
US6340806B1 (en) * | 1999-12-28 | 2002-01-22 | General Scanning Inc. | Energy-efficient method and system for processing target material using an amplified, wavelength-shifted pulse train |
US20040134896A1 (en) * | 1999-12-28 | 2004-07-15 | Bo Gu | Laser-based method and system for memory link processing with picosecond lasers |
US6887804B2 (en) * | 2000-01-10 | 2005-05-03 | Electro Scientific Industries, Inc. | Passivation processing over a memory link |
US20030151053A1 (en) * | 2000-01-10 | 2003-08-14 | Yunlong Sun | Processing a memory link with a set of at least two laser pulses |
US6574250B2 (en) * | 2000-01-10 | 2003-06-03 | Electro Scientific Industries, Inc. | Laser system and method for processing a memory link with a burst of laser pulses having ultrashort pulse widths |
US6541731B2 (en) * | 2000-01-25 | 2003-04-01 | Aculight Corporation | Use of multiple laser sources for rapid, flexible machining and production of vias in multi-layered substrates |
US6697394B2 (en) * | 2000-02-10 | 2004-02-24 | Jenoptik Ldt Gmbh | Directly modulatable laser |
US6838639B2 (en) * | 2000-02-15 | 2005-01-04 | Datacard Corporation | Method for the machining of workpieces by means of several laser beams |
US6423925B1 (en) * | 2000-02-17 | 2002-07-23 | Universal Laser Systems, Inc. | Apparatus and method for combining multiple laser beams in laser material processing systems |
US20020050488A1 (en) * | 2000-03-01 | 2002-05-02 | Dmitri Nikitin | Method and apparatus for thermally processing quartz using a plurality of laser beams |
US6313433B1 (en) * | 2000-04-03 | 2001-11-06 | Universal Laser Systems, Inc | Laser material processing system with multiple laser sources apparatus and method |
US6737635B2 (en) * | 2000-04-04 | 2004-05-18 | Leica Microsystems Heidelberg Gmbh | Apparatus for combining light and confocal scanning microscope |
US6605799B2 (en) * | 2000-05-25 | 2003-08-12 | Westar Photonics | Modulation of laser energy with a predefined pattern |
US6580055B2 (en) * | 2000-06-09 | 2003-06-17 | Sumitomo Heavy Industries, Ltd. | Laser processing apparatus and method |
US6879605B2 (en) * | 2000-07-24 | 2005-04-12 | Laserfront Technologies, Inc. | Method and apparatus for performing pattern defect repair using Q-switched mode-locked pulse laser |
US6608281B2 (en) * | 2000-08-10 | 2003-08-19 | Mitsubishi Heavy Industries, Ltd. | Laser beam machining head and laser beam machining apparatus having same |
US6875951B2 (en) * | 2000-08-29 | 2005-04-05 | Mitsubishi Denki Kabushiki Kaisha | Laser machining device |
US6531677B2 (en) * | 2000-10-06 | 2003-03-11 | Hitachi Via Mechanics, Ltd. | Method and apparatus for drilling printed wiring boards |
US6531678B2 (en) * | 2000-10-11 | 2003-03-11 | Murata Manufacturing Co., Ltd. | Method for processing ceramic green sheet and laser beam machine used therefor |
US6625181B1 (en) * | 2000-10-23 | 2003-09-23 | U.C. Laser Ltd. | Method and apparatus for multi-beam laser machining |
US6563083B2 (en) * | 2000-12-18 | 2003-05-13 | Thyssen Laser-Technik Gmbh | Laser robot for workpiece machining and method for workpiece machining with a laser robot |
US7027155B2 (en) * | 2001-03-29 | 2006-04-11 | Gsi Lumonics Corporation | Methods and systems for precisely relatively positioning a waist of a pulsed laser beam and method and system for controlling energy delivered to a target structure |
US20020167581A1 (en) * | 2001-03-29 | 2002-11-14 | Cordingley James J. | Methods and systems for thermal-based laser processing a multi-material device |
US6720519B2 (en) * | 2001-11-30 | 2004-04-13 | Matsushita Electric Industrial Co., Ltd. | System and method of laser drilling |
US6664498B2 (en) * | 2001-12-04 | 2003-12-16 | General Atomics | Method and apparatus for increasing the material removal rate in laser machining |
US7006237B2 (en) * | 2002-03-26 | 2006-02-28 | Mitsubishi Denki Kabushiki Kaisha | Laser beam positioning device for laser processing equipment |
US6951995B2 (en) * | 2002-03-27 | 2005-10-04 | Gsi Lumonics Corp. | Method and system for high-speed, precise micromachining an array of devices |
US20040104208A1 (en) * | 2002-03-28 | 2004-06-03 | Kenichi Ijima | Laser machining apparatus |
US6940888B2 (en) * | 2002-11-21 | 2005-09-06 | New Wave Research | Dual head laser system with intra-cavity polarization, and particle image velocimetry system using same |
US20040173590A1 (en) * | 2002-12-17 | 2004-09-09 | Hitachi Via Mechanics Ltd. | Multi-axis laser machine, method for machining with the same, and recording medium recording computer program for controlling the same |
US6849824B2 (en) * | 2002-12-26 | 2005-02-01 | Hitachi Via Mechanics, Ltd. | Multibeam laser drilling apparatus |
US6909735B2 (en) * | 2003-04-10 | 2005-06-21 | Hitachi Via Mechanics, Ltd. | System and method for generating and controlling multiple independently steerable laser beam for material processing |
US20050254530A1 (en) * | 2004-05-14 | 2005-11-17 | Yunlong Sun | Multi-output harmonic laser and methods employing same |
US7027199B2 (en) * | 2004-06-07 | 2006-04-11 | Electro Scientific Industries, Inc. | AOM modulation techniques for facilitating pulse-to-pulse energy stability in laser systems |
US7133187B2 (en) * | 2004-06-07 | 2006-11-07 | Electro Scientific Industries, Inc. | AOM modulation techniques employing plurality of transducers to improve laser system performance |
US7133182B2 (en) * | 2004-06-07 | 2006-11-07 | Electro Scientific Industries, Inc. | AOM frequency and amplitude modulation techniques for facilitating full beam extinction in laser systems |
US7133188B2 (en) * | 2004-06-07 | 2006-11-07 | Electro Scientific Industries, Inc. | AOM modulation techniques employing an upstream Bragg adjustment device |
US7133186B2 (en) * | 2004-06-07 | 2006-11-07 | Electro Scientific Industries, Inc. | AOM modulation techniques employing transducers to modulate different axes |
US20060114948A1 (en) * | 2004-11-29 | 2006-06-01 | Lo Ho W | Workpiece processing system using a common imaged optical assembly to shape the spatial distributions of light energy of multiple laser beams |
US20060128073A1 (en) * | 2004-12-09 | 2006-06-15 | Yunlong Sun | Multiple-wavelength laser micromachining of semiconductor devices |
Cited By (27)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100046561A1 (en) * | 2003-06-30 | 2010-02-25 | Electro Scientific Industries, Inc. | High energy pulse suppression method |
US20050100062A1 (en) * | 2003-06-30 | 2005-05-12 | Electro Scientific Industries, Inc. | High energy pulse suppression method |
US7616669B2 (en) | 2003-06-30 | 2009-11-10 | Electro Scientific Industries, Inc. | High energy pulse suppression method |
US8081668B2 (en) | 2003-06-30 | 2011-12-20 | Electro Scientific Industries, Inc. | High energy pulse suppression method |
WO2006057660A2 (en) * | 2004-11-24 | 2006-06-01 | Electro Scientific Industries, Inc. | High energy pulse suppression method |
WO2006057660A3 (en) * | 2004-11-24 | 2007-05-03 | Electro Scient Ind Inc | High energy pulse suppression method |
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US20060114948A1 (en) * | 2004-11-29 | 2006-06-01 | Lo Ho W | Workpiece processing system using a common imaged optical assembly to shape the spatial distributions of light energy of multiple laser beams |
US20090188901A1 (en) * | 2006-04-10 | 2009-07-30 | Board Of Trustees Of Michigan State University | Laser Material Processing System |
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US20080029491A1 (en) * | 2006-07-20 | 2008-02-07 | Gsi Group Corporation | System and method for laser processing at non-constant velocities |
US8084706B2 (en) * | 2006-07-20 | 2011-12-27 | Gsi Group Corporation | System and method for laser processing at non-constant velocities |
US20100038349A1 (en) * | 2008-08-18 | 2010-02-18 | Industrial Technology Research Institute | Laser marking method and laser marking system |
US20110236645A1 (en) * | 2010-03-26 | 2011-09-29 | Electro Scientific Industries, Inc. | Method of manufacturing a panel with occluded microholes and products made thereby |
US8524127B2 (en) | 2010-03-26 | 2013-09-03 | Electro Scientific Industries, Inc. | Method of manufacturing a panel with occluded microholes |
US8692151B2 (en) * | 2010-03-31 | 2014-04-08 | Applied Materials, Inc. | Laser beam positioning system |
US20110239421A1 (en) * | 2010-03-31 | 2011-10-06 | Applied Materials, Inc. | Laser beam positioning system |
US10292865B2 (en) | 2011-06-24 | 2019-05-21 | The Regents Of The University Of California | Nonlinear optical photodynamic therapy (NLO-PDT) of the cornea |
US9095414B2 (en) * | 2011-06-24 | 2015-08-04 | The Regents Of The University Of California | Nonlinear optical photodynamic therapy (NLO-PDT) of the cornea |
US9036247B2 (en) | 2011-07-05 | 2015-05-19 | Electro Scientific Industries, Inc. | Systems and methods for providing temperature stability of acousto-optic beam deflectors and acousto-optic modulators during use |
WO2014152526A1 (en) * | 2013-03-15 | 2014-09-25 | Electro Scientific Industries, Inc. | Laser systems and methods for aod tool settling for aod travel reduction |
US9724782B2 (en) | 2013-03-15 | 2017-08-08 | Electro Scientific Industries, Inc. | Laser systems and methods for AOD tool settling for AOD travel reduction |
WO2017044646A1 (en) * | 2015-09-09 | 2017-03-16 | Electro Scientific Industries, Inc. | Laser processing apparatus, methods of laser-processing workpieces and related arrangements |
US11077526B2 (en) | 2015-09-09 | 2021-08-03 | Electro Scientific Industries, Inc. | Laser processing apparatus, methods of laser-processing workpieces and related arrangements |
TWI798238B (en) * | 2017-11-08 | 2023-04-11 | 日商住友重機械工業股份有限公司 | Laser processing device |
WO2020080652A1 (en) * | 2018-10-15 | 2020-04-23 | 원텍 주식회사 | Laser beam generation device |
Also Published As
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CA2530688A1 (en) | 2005-01-20 |
US6947454B2 (en) | 2005-09-20 |
CN1813339A (en) | 2006-08-02 |
TW200505117A (en) | 2005-02-01 |
CN1813339B (en) | 2010-10-13 |
KR101123231B1 (en) | 2012-03-20 |
DE112004001190T5 (en) | 2006-05-11 |
JP4331752B2 (en) | 2009-09-16 |
GB0601470D0 (en) | 2006-03-08 |
KR20060034652A (en) | 2006-04-24 |
GB2420004A (en) | 2006-05-10 |
TWI348799B (en) | 2011-09-11 |
US20040264517A1 (en) | 2004-12-30 |
WO2005006422A1 (en) | 2005-01-20 |
JP2007527608A (en) | 2007-09-27 |
GB2420004B (en) | 2007-01-03 |
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