CA1262291A - Method and apparatus for measuring the ion implant dosage in a semiconductor crystal - Google Patents
Method and apparatus for measuring the ion implant dosage in a semiconductor crystalInfo
- Publication number
- CA1262291A CA1262291A CA000552742A CA552742A CA1262291A CA 1262291 A CA1262291 A CA 1262291A CA 000552742 A CA000552742 A CA 000552742A CA 552742 A CA552742 A CA 552742A CA 1262291 A CA1262291 A CA 1262291A
- Authority
- CA
- Canada
- Prior art keywords
- semiconductor crystal
- harmonic
- fundamental wavelength
- light energy
- directing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- 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
- H01L21/265—Bombardment with radiation with high-energy radiation producing ion implantation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/636—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited using an arrangement of pump beam and probe beam; using the measurement of optical non-linear properties
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/26—Testing of individual semiconductor devices
- G01R31/265—Contactless testing
- G01R31/2656—Contactless testing using non-ionising electromagnetic radiation, e.g. optical radiation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N2021/8461—Investigating impurities in semiconductor, e.g. Silicon
Abstract
ABSTRACT
A technique for measuring the ion implant dosage involves method and apparatus for directing pulses of coherent radiation from a laser to the surface of a semiconductor that has been subjected to ion implant.
The intensity of the third harmonic reflected from the semiconductor is determined and correlated to determine the ion dosage within the semiconductor.
A technique for measuring the ion implant dosage involves method and apparatus for directing pulses of coherent radiation from a laser to the surface of a semiconductor that has been subjected to ion implant.
The intensity of the third harmonic reflected from the semiconductor is determined and correlated to determine the ion dosage within the semiconductor.
Description
~ 1 -J
METHOD AND APP~RATUS FOR MEASURING
THE ION IMPLANT DOSAGE IN A SEMICO~DUCTOR CRYST~L
~S~9BQ~ND QP~UUE~ E~Q~
Field o~ hQ-E~-~ntio~
Ths pre~ent inventi.on is directed to the field of semiconductor manu~acturiny and more specifically to the area of ion do~e measurements per~ormed during the manufacturing proce~s.
L
Dçscrip~iQn ~f the Pr~Q~_Art Ion implantation is a common semiconductor ?
processin~ ~tep used to modify the near-surface chemical and physical composition of a wafer by the injection of high energy ions. The crystal lattice o the semiconducto~ is damaged by the ion injection process.
Normally, the ion beam iæ small ~5mm), compared with the size of the wafer (75-200mm). Therefore, the scanning of the ion beam with respect to the wa~er ;s necessary to achieve a uni~orm ion dose. Variation in ion dose may occur over the wa~er surface due to a number o factors inf~luding improper scanning, wafer charging o~ beam instability. Of course ~uch variation in the ion dose will give ri~e to variation in the electrical properties of the ~emiconductor device being fabricated. Variatîon !:
in the ion ~ose then, in turn, has a ~irect impact on the quality yield. Accordingly, techniques have been developed that give an estimation as to ion do~e and in : some cases the uniformity of the dose.
One of the known measurement techni'ques involves direct sheet resistance. In that method~ the wafer is ~ubjected to a high temper~ture annealing step in order to eliminate lattice damage and to activate the implanted ions. Subsequently, a colline~r four point probe is placed into electrical contact with the wafer surface and current is forced through two of the prohas. Yoltage i8 then measured acroæs the other two probes and a rssistance reading i~ made.
Another method utili~es thermal waves that ars propagated into the wa~er. In that method, hiyh .
frequency pulses of laser ~nergy are directed to be incident on the samiconduc~or surface and ~tablish a train of thermal waves that propagate into the wafer.
The surface temperature of the wafer is modulated as these waves are scattered by subsuracs, implant induced damage. The wafer surface temperature is monitored by the reflection of a second laser beam, thus giving a signal relatea to ion do~e.
An indirect method of measuring ion dose is termed optical dosimetry. In that method, a glass wafor coated with a photo-resist layar i6 used in the implanter a6 a dumm~ te~t pioce. In that test piece, hi~h implantation re~ults in darkening o~ the photo-resi~t layer. A~ a re~ult, the transmi~ion of collimate~ light directed throu~h the photo-re~i~t is affected and may be measured a~ a relation of the ion dose.
SUMM~RY OF TH~ INV~NTI~N
It is an object of the present invention to provide a noncontacting and nondeætructive method and apparatus for directly measuring the ion dose in an ion implanted semiconductor crystal.
It it another object of the present invention to provide a measuring techni~ue whereby the ion dosage can ,~
be determined during processing of semiconductor wafers prior to annealing so as to detect flaws in the ion ?,~
implant stage o~ the prscess prior, to completing the fabrication process.
It is still another object of the present invention to pxovi~e a measuring techniqua that is ideally suited for automation within a semiconductor pxoduction yrocess so as to monitor quality and provide instantaneous feedback as to variations in ion dosage.
It i a ~urther object of the present invention to prov.ide an ion dose measuring sy~tem that is applicable to any cry~t~l and semiconductor material including silicon, germanium, gallium ars~nide and indium phosphide. ;;~
It is a still further object of the present invention to provide an ion dose measuring technique which utilizes a source of coherent light energy directed at the surface o~ an ion implante~ semiconducto~ crystal and to sense and measure the intensity of the third harmonic of the light energy reflected from the crystal ~tructure of the semiconductor.
~ 1 1 Figure 1 illuætrates an embodimen~ of the apparatus employed in the present invention.
Figure 2 is a plot of ion dose intensity measurements taken with the apparatuæ shown in Figure 1, in vacuum and air medium~.
Figure ~ illustrates a test wafer with prescribed ion dose boundaries.
Figure ~ is a map of tha measurements made on the test wafer shown in Figure 4 utilizing the apparatus shown in Figure 1.
DESCRIPTIO~ OE THR ~R~F~RED E~BODIMENT
In the embodiment shown in Figure 1, a 3S Q-switched, Nd:~A~ laser 10 i~ provided which generat~s d. ,J,i, ~ ~ , _ 9 4ns pulses at a lOHZ rate with a fundamental w~valength of 1.06~. The beam of pul~ed onergy proaucea by the laser 10 is directed through a polarizer 12 and collimating optics 14. The collimated beam is directed 5 to a dichroic mirror 1~ where it is reflected onto the surface of a semiconductor wafer 30. The wafer 30 is normall~ placed on an X-Y movable fi~ture in order that multiple sample mea~urements can be made acros~ the r surface of the semiconductor crystal 30. An alternatiYe 10 apparatus configuration may provide for a scanning beam and a fi~ed semiconductor wafer.
As the pul~e~ of beam energy impi~ye onto the sem;conductor crystal 30, harmonics of the fundamental wavelsngth ~re caused to be reflected hy the nonlinear 15 optical proparty of the semicon~uctor 30. For in3tance, the second harmonic of ths fundamental wavelength is produced. However, it has been found that the second harmonic generally emitted from centrosymmetric crystals, such as silicon, is limited to the top several atomic 20 layers of the cry~tal. On the other hand, Applicants have found that the third harmonic i8 gen~rated at depths ~rom the æurface of the crystal which are govern0d by the ~bsorption length of the ~undamental wavelength or tha~
of the third harmonic. Accordingly, the probed ~epth 2S correspolldiny to an ab~orption length o~ approximately 10nm into the surface of the samiconductor crystal corresponds to the volume o~ material normally modified by implantation of ions. O course the lattice damage caused by the ion implantations process af~ects the 30 intensity of the third harmonic generation as compared to the pure crystal structure. As such, variations in the ion dosP will appear a8 variation~ in these third harmonic emissionæ from the surface of the semiconductor crystal 30.
The dichroic mirror 18, in the embodiment shown -- 5 ~
in Figure 1, is selectad to reflect the fundamental wavelength and transmit the third harmonic of the fundamental. The third harmonic emitted from the semiconductor crystal 30 is transmitted through the dichroic mirror 18, a filter 20 and a polari~er 22 to a sensor 24. In this case, the sensor 24 is a photomultiplier tube which provides an electrical output signal that corre~ponds to the intensity o the third harmonic of the fundamental frequency available at the sensor 24. The output of photomultiplier 24 is f~d to an integrater/averager ~ystem 26 such a~ is commercially available. The integrater/avera~er employed in the e~periment6 leading up to the present invention was a Model 4400 Signal Processing System pro~uced by EG&G
Princeton Applie~ Research o Princeton, New 3ersey.
The function of the integraterfaverager 26 is to analyze the pulæed output of the photo multiplier senæor 24 and to provide an output indicating the relative ;-intensity of the third harmonic at ~ensor.
The distance indicatsd as "~ between the ?
surface of the æemiconductor cr~stal 30 and the poin~ on the ~ichroic mirror 18 at which the beam is re~lected towards the semiconductor i~ an important consid~ration when the medium between those two point~ is air. In a 25 vacuum, the di8tance "L" i~ arbitrary. However, in an ~;
air medium, a third harmonic is generated by the air and dispersion causes intensity variations o~ a sinusoidal nature ~o occur in the path betwaen the dichroic mirror 18 and the semiconductor 30. It has been found that when 3~ "L~ eguals an even number of coherence lenyths of the third harmonic generat~d in air, the most consistent measuremen~s occur which closely appro~ima~e utilizing a vacuum medium. I
The fact that air can be used as a medium in f 35 performing th~ aforementioned mea~urement makes such measurements hi0hly sui~ed to automated production utilization.
The graph in Figure 2 illustrates the results of comparing measurements ~aken using the aforementioned apparatus of various samples in which ion doses are within the range indicated. The continuous line 101 indicates the measurements taken of the various sampl~s in a vacuurn medium. This short dashed line 103 indicates the same samples made in an air madium in which the distance between the mirror la and the surfaces o~ the samples was appro~imately 0.4 coheran¢e lengths for third harmonic generation (LCoh). The long dashed line 105 indicates the æame samples mea~ured by the aforementioned apparatus wherein the distance ~Lu betwieen the mirror 18 and the top surfaces of the samples was equal to 2 LCoh.
It can be seen from Figure 2 that hy utilizing an even number of LCoh as the value for "Ln, the use of the apparatus in air will be appro~imately equivalent to the results when used in a vacuum.
Figure 3 illustrates a sample wafer defining three zones o ion im~lant having distinct doses of 50~EV
P~ ions. In zone ~A~, the dose is 3X1013 cm 2, while the dose in æone "B" i~ 1.8X1013 cm 2 and the do~e in zone "Cn i8 5. 6X1013 Cm~2-E'igure 4 illustrat~ a map o mea~urements taken o~ the ~ample shown in Figure 3 utilizing a range of relative intensities of the measured third harmonic to ~efine the boundary regions A', B' and C'.
While the aforementioned apparatus describes the use of a polarizex 12 and an analyzer 22 in association with the sampling pulses, it should be pointed out that rotational movement of the semiconductor wafer 30 will cause variations in the sensed third harmonic reflerted to the sensor 24. ~ccordingly, it may be desirable to utilize a quarter wave plate such as that shown in ",~1 phantom linee and de6ignated as 16 in Figure 1 to provide circular polarization of the beam and ~liminata the orientation variations.
The intensity o the pulse energy from the laser source 10 was selected in the present invention to have a pulse energy of approximately 40mJ. The energy was selected to be well below the annealing threshold for the implant amorphized silicon crystal but at the same time high enough to cause a third harmonic generation in the crystal surface ~hat iæ easily detectable by the sensor 24. Certain variables in the pre~ent invention provide for ad~ed fle~ibility. For instance, the probed depth o~
ef~ective measurement in the semiconductor crystal can he controlled by the ~elected wavelength o the ~undamental ,~
radiation. On the other hand shorter pulse widths are pre~erable since higher power pulses may be available while maintaining ~he average anergy below the annealing threshold. In addition, higher pulse rates are preferabls in ordsr ~o reduce the analysis time.
It will ba apparent that many modifications and variations m~y be implemented without departing from the scope of the nov~l concept of thi8 invention. Therefore, it is intended by the appended claim~ to cover all ~uch modifications and variations whichlfall within the true spirit an~ scope o~ the invention.
i ~0
METHOD AND APP~RATUS FOR MEASURING
THE ION IMPLANT DOSAGE IN A SEMICO~DUCTOR CRYST~L
~S~9BQ~ND QP~UUE~ E~Q~
Field o~ hQ-E~-~ntio~
Ths pre~ent inventi.on is directed to the field of semiconductor manu~acturiny and more specifically to the area of ion do~e measurements per~ormed during the manufacturing proce~s.
L
Dçscrip~iQn ~f the Pr~Q~_Art Ion implantation is a common semiconductor ?
processin~ ~tep used to modify the near-surface chemical and physical composition of a wafer by the injection of high energy ions. The crystal lattice o the semiconducto~ is damaged by the ion injection process.
Normally, the ion beam iæ small ~5mm), compared with the size of the wafer (75-200mm). Therefore, the scanning of the ion beam with respect to the wa~er ;s necessary to achieve a uni~orm ion dose. Variation in ion dose may occur over the wa~er surface due to a number o factors inf~luding improper scanning, wafer charging o~ beam instability. Of course ~uch variation in the ion dose will give ri~e to variation in the electrical properties of the ~emiconductor device being fabricated. Variatîon !:
in the ion ~ose then, in turn, has a ~irect impact on the quality yield. Accordingly, techniques have been developed that give an estimation as to ion do~e and in : some cases the uniformity of the dose.
One of the known measurement techni'ques involves direct sheet resistance. In that method~ the wafer is ~ubjected to a high temper~ture annealing step in order to eliminate lattice damage and to activate the implanted ions. Subsequently, a colline~r four point probe is placed into electrical contact with the wafer surface and current is forced through two of the prohas. Yoltage i8 then measured acroæs the other two probes and a rssistance reading i~ made.
Another method utili~es thermal waves that ars propagated into the wa~er. In that method, hiyh .
frequency pulses of laser ~nergy are directed to be incident on the samiconduc~or surface and ~tablish a train of thermal waves that propagate into the wafer.
The surface temperature of the wafer is modulated as these waves are scattered by subsuracs, implant induced damage. The wafer surface temperature is monitored by the reflection of a second laser beam, thus giving a signal relatea to ion do~e.
An indirect method of measuring ion dose is termed optical dosimetry. In that method, a glass wafor coated with a photo-resist layar i6 used in the implanter a6 a dumm~ te~t pioce. In that test piece, hi~h implantation re~ults in darkening o~ the photo-resi~t layer. A~ a re~ult, the transmi~ion of collimate~ light directed throu~h the photo-re~i~t is affected and may be measured a~ a relation of the ion dose.
SUMM~RY OF TH~ INV~NTI~N
It is an object of the present invention to provide a noncontacting and nondeætructive method and apparatus for directly measuring the ion dose in an ion implanted semiconductor crystal.
It it another object of the present invention to provide a measuring techni~ue whereby the ion dosage can ,~
be determined during processing of semiconductor wafers prior to annealing so as to detect flaws in the ion ?,~
implant stage o~ the prscess prior, to completing the fabrication process.
It is still another object of the present invention to pxovi~e a measuring techniqua that is ideally suited for automation within a semiconductor pxoduction yrocess so as to monitor quality and provide instantaneous feedback as to variations in ion dosage.
It i a ~urther object of the present invention to prov.ide an ion dose measuring sy~tem that is applicable to any cry~t~l and semiconductor material including silicon, germanium, gallium ars~nide and indium phosphide. ;;~
It is a still further object of the present invention to provide an ion dose measuring technique which utilizes a source of coherent light energy directed at the surface o~ an ion implante~ semiconducto~ crystal and to sense and measure the intensity of the third harmonic of the light energy reflected from the crystal ~tructure of the semiconductor.
~ 1 1 Figure 1 illuætrates an embodimen~ of the apparatus employed in the present invention.
Figure 2 is a plot of ion dose intensity measurements taken with the apparatuæ shown in Figure 1, in vacuum and air medium~.
Figure ~ illustrates a test wafer with prescribed ion dose boundaries.
Figure ~ is a map of tha measurements made on the test wafer shown in Figure 4 utilizing the apparatus shown in Figure 1.
DESCRIPTIO~ OE THR ~R~F~RED E~BODIMENT
In the embodiment shown in Figure 1, a 3S Q-switched, Nd:~A~ laser 10 i~ provided which generat~s d. ,J,i, ~ ~ , _ 9 4ns pulses at a lOHZ rate with a fundamental w~valength of 1.06~. The beam of pul~ed onergy proaucea by the laser 10 is directed through a polarizer 12 and collimating optics 14. The collimated beam is directed 5 to a dichroic mirror 1~ where it is reflected onto the surface of a semiconductor wafer 30. The wafer 30 is normall~ placed on an X-Y movable fi~ture in order that multiple sample mea~urements can be made acros~ the r surface of the semiconductor crystal 30. An alternatiYe 10 apparatus configuration may provide for a scanning beam and a fi~ed semiconductor wafer.
As the pul~e~ of beam energy impi~ye onto the sem;conductor crystal 30, harmonics of the fundamental wavelsngth ~re caused to be reflected hy the nonlinear 15 optical proparty of the semicon~uctor 30. For in3tance, the second harmonic of ths fundamental wavelength is produced. However, it has been found that the second harmonic generally emitted from centrosymmetric crystals, such as silicon, is limited to the top several atomic 20 layers of the cry~tal. On the other hand, Applicants have found that the third harmonic i8 gen~rated at depths ~rom the æurface of the crystal which are govern0d by the ~bsorption length of the ~undamental wavelength or tha~
of the third harmonic. Accordingly, the probed ~epth 2S correspolldiny to an ab~orption length o~ approximately 10nm into the surface of the samiconductor crystal corresponds to the volume o~ material normally modified by implantation of ions. O course the lattice damage caused by the ion implantations process af~ects the 30 intensity of the third harmonic generation as compared to the pure crystal structure. As such, variations in the ion dosP will appear a8 variation~ in these third harmonic emissionæ from the surface of the semiconductor crystal 30.
The dichroic mirror 18, in the embodiment shown -- 5 ~
in Figure 1, is selectad to reflect the fundamental wavelength and transmit the third harmonic of the fundamental. The third harmonic emitted from the semiconductor crystal 30 is transmitted through the dichroic mirror 18, a filter 20 and a polari~er 22 to a sensor 24. In this case, the sensor 24 is a photomultiplier tube which provides an electrical output signal that corre~ponds to the intensity o the third harmonic of the fundamental frequency available at the sensor 24. The output of photomultiplier 24 is f~d to an integrater/averager ~ystem 26 such a~ is commercially available. The integrater/avera~er employed in the e~periment6 leading up to the present invention was a Model 4400 Signal Processing System pro~uced by EG&G
Princeton Applie~ Research o Princeton, New 3ersey.
The function of the integraterfaverager 26 is to analyze the pulæed output of the photo multiplier senæor 24 and to provide an output indicating the relative ;-intensity of the third harmonic at ~ensor.
The distance indicatsd as "~ between the ?
surface of the æemiconductor cr~stal 30 and the poin~ on the ~ichroic mirror 18 at which the beam is re~lected towards the semiconductor i~ an important consid~ration when the medium between those two point~ is air. In a 25 vacuum, the di8tance "L" i~ arbitrary. However, in an ~;
air medium, a third harmonic is generated by the air and dispersion causes intensity variations o~ a sinusoidal nature ~o occur in the path betwaen the dichroic mirror 18 and the semiconductor 30. It has been found that when 3~ "L~ eguals an even number of coherence lenyths of the third harmonic generat~d in air, the most consistent measuremen~s occur which closely appro~ima~e utilizing a vacuum medium. I
The fact that air can be used as a medium in f 35 performing th~ aforementioned mea~urement makes such measurements hi0hly sui~ed to automated production utilization.
The graph in Figure 2 illustrates the results of comparing measurements ~aken using the aforementioned apparatus of various samples in which ion doses are within the range indicated. The continuous line 101 indicates the measurements taken of the various sampl~s in a vacuurn medium. This short dashed line 103 indicates the same samples made in an air madium in which the distance between the mirror la and the surfaces o~ the samples was appro~imately 0.4 coheran¢e lengths for third harmonic generation (LCoh). The long dashed line 105 indicates the æame samples mea~ured by the aforementioned apparatus wherein the distance ~Lu betwieen the mirror 18 and the top surfaces of the samples was equal to 2 LCoh.
It can be seen from Figure 2 that hy utilizing an even number of LCoh as the value for "Ln, the use of the apparatus in air will be appro~imately equivalent to the results when used in a vacuum.
Figure 3 illustrates a sample wafer defining three zones o ion im~lant having distinct doses of 50~EV
P~ ions. In zone ~A~, the dose is 3X1013 cm 2, while the dose in æone "B" i~ 1.8X1013 cm 2 and the do~e in zone "Cn i8 5. 6X1013 Cm~2-E'igure 4 illustrat~ a map o mea~urements taken o~ the ~ample shown in Figure 3 utilizing a range of relative intensities of the measured third harmonic to ~efine the boundary regions A', B' and C'.
While the aforementioned apparatus describes the use of a polarizex 12 and an analyzer 22 in association with the sampling pulses, it should be pointed out that rotational movement of the semiconductor wafer 30 will cause variations in the sensed third harmonic reflerted to the sensor 24. ~ccordingly, it may be desirable to utilize a quarter wave plate such as that shown in ",~1 phantom linee and de6ignated as 16 in Figure 1 to provide circular polarization of the beam and ~liminata the orientation variations.
The intensity o the pulse energy from the laser source 10 was selected in the present invention to have a pulse energy of approximately 40mJ. The energy was selected to be well below the annealing threshold for the implant amorphized silicon crystal but at the same time high enough to cause a third harmonic generation in the crystal surface ~hat iæ easily detectable by the sensor 24. Certain variables in the pre~ent invention provide for ad~ed fle~ibility. For instance, the probed depth o~
ef~ective measurement in the semiconductor crystal can he controlled by the ~elected wavelength o the ~undamental ,~
radiation. On the other hand shorter pulse widths are pre~erable since higher power pulses may be available while maintaining ~he average anergy below the annealing threshold. In addition, higher pulse rates are preferabls in ordsr ~o reduce the analysis time.
It will ba apparent that many modifications and variations m~y be implemented without departing from the scope of the nov~l concept of thi8 invention. Therefore, it is intended by the appended claim~ to cover all ~uch modifications and variations whichlfall within the true spirit an~ scope o~ the invention.
i ~0
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Apparatus for measuring the ion implantation dose of a semiconductor crystal, comprising:
means for providing a beam of coherent light energy at a predetermined fundamental wavelength, means for pulsing said coherent light energy beam to provide pulses of light energy having a predetermined pulse width and repetition rate;
means for directing said pulsed coherent light energy beam onto a defined area of said semiconductor crystal;
means for sensing the third harmonic of said fundamental wavelength reflected from said defined area of said semiconductor crystal; and means connected to said sensing means for measuring the intensity of said third harmonic of energy reflected from said semiconductor crystal.
means for providing a beam of coherent light energy at a predetermined fundamental wavelength, means for pulsing said coherent light energy beam to provide pulses of light energy having a predetermined pulse width and repetition rate;
means for directing said pulsed coherent light energy beam onto a defined area of said semiconductor crystal;
means for sensing the third harmonic of said fundamental wavelength reflected from said defined area of said semiconductor crystal; and means connected to said sensing means for measuring the intensity of said third harmonic of energy reflected from said semiconductor crystal.
2. Apparatus as in claim 1, wherein said directing means included a dichroic mirror that is oriented between said providing means and said semiconductor crystal to reflect said fundamental wavelength towards said semiconductor crystal and to transmit said third harmonic of said fundamental wavelength.
3. Apparatus as in claim 2, wherein said dichroic mirror is also located between said sensing means and said semiconductor crystal to transmit only the third harmonic of said fundamental wavelength.
4. An apparatus as in claim 3, wherein said directing means directs said beam of coherent light energy to have an angle of incidence that is normal to the surface of the semiconductor crystal.
5. An apparatus as in claim 4, wherein said sensing means receives the third harmonic of said fundamental wavelength reflected from said semiconductor crystal in a direction normal to the semiconductor crystal surface.
6. An apparatus as in claim 5, wherein the medium between the directing means and the surface of the semiconductor crystal is air and the distance between the dichroic mirror and the surface of the semiconductor crystal is equal to an even multiple of the coherence length for third harmonic generation in air.
7. A method of measuring the ion implantation dose of a semiconductor crystal, comprising the steps of:
providing a source to generate a beam of coherent light energy at a predetermined fundamental wavelength;
pulsing said coherent light energy beam to provide pulses of light energy having a predetermined pulse width and repetition rate;
directing said pulsed coherent light energy beam onto a defined area of said semiconductor crystal;
sensing the third harmonic of said fundamental wavelength reflected from said defined area of said semiconductor crystal; and measuring the intensity of said third harmonic of energy reflected from said semiconductor crystal.
providing a source to generate a beam of coherent light energy at a predetermined fundamental wavelength;
pulsing said coherent light energy beam to provide pulses of light energy having a predetermined pulse width and repetition rate;
directing said pulsed coherent light energy beam onto a defined area of said semiconductor crystal;
sensing the third harmonic of said fundamental wavelength reflected from said defined area of said semiconductor crystal; and measuring the intensity of said third harmonic of energy reflected from said semiconductor crystal.
8. A method as in claim 7, wherein said step of directing includes providing a dichroic mirror that is also located between said beam source and said semiconductor crystal, oriented to reflect said fundamental wavelength towards said semiconductor crystal and to transmit said third harmonic of said fundamental wavelength.
9. A method as in claim 8, wherein said step of sensing includes the step of providing means for sensing light energy and said dichroic mirror is provided and located between said sensing means and said semiconductor crystal to transmit only the third harmonic of said fundamental wavelength to said sensing means.
10. A method as in claim 9 wherein said step of directing is performed to direct said beam of coherent light energy to have an angle of incidence that is normal to the surface of the semiconductor crystal.
11. A method as in claim 10, wherein said sensing means is provided to receive the third harmonic of said fundamental wavelength reflected from said semiconductor crystal in a direction normal to the semiconductor crystal surface.
12. A method as in claim 11, wherein the medium between the directing means and the surface of the semiconductor crystal is air and the dichroic mirror is provided at a distance from the surface of the semiconductor crystal that is equal to an even multiple of the coherence length for third harmonic generation in air.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/937,158 US4755049A (en) | 1986-12-02 | 1986-12-02 | Method and apparatus for measuring the ion implant dosage in a semiconductor crystal |
| US937,158 | 1986-12-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1262291A true CA1262291A (en) | 1989-10-10 |
Family
ID=25469577
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000552742A Expired CA1262291A (en) | 1986-12-02 | 1987-11-25 | Method and apparatus for measuring the ion implant dosage in a semiconductor crystal |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4755049A (en) |
| JP (1) | JPS63151042A (en) |
| KR (1) | KR880008417A (en) |
| CA (1) | CA1262291A (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5074669A (en) * | 1989-12-12 | 1991-12-24 | Therma-Wave, Inc. | Method and apparatus for evaluating ion implant dosage levels in semiconductors |
| US5185273A (en) * | 1991-09-30 | 1993-02-09 | Motorola, Inc. | Method for measuring ions implanted into a semiconductor substrate |
| TW394977B (en) * | 1998-04-21 | 2000-06-21 | United Microelectronics Corp | A recycle method for the monitor control chip |
| US7029933B2 (en) * | 2004-06-22 | 2006-04-18 | Tech Semiconductor Singapore Pte. Ltd. | Method for monitoring ion implant doses |
| US7250313B2 (en) * | 2004-09-30 | 2007-07-31 | Solid State Measurements, Inc. | Method of detecting un-annealed ion implants |
| KR100699889B1 (en) * | 2005-12-29 | 2007-03-28 | 삼성전자주식회사 | Method of manufacturing semiconductor device including ion implanting under variable conditions |
| US8415620B2 (en) * | 2010-01-11 | 2013-04-09 | International Business Machines Corporation | Determining doping type and level in semiconducting nanostructures |
| US8581204B2 (en) * | 2011-09-16 | 2013-11-12 | Taiwan Semiconductor Manufacturing Company, Ltd. | Apparatus for monitoring ion implantation |
| US10019565B2 (en) | 2015-12-17 | 2018-07-10 | Honeywell Federal Manufacturing & Technologies, Llc | Method of authenticating integrated circuits using optical characteristics of physically unclonable functions |
| US11041827B2 (en) * | 2019-04-12 | 2021-06-22 | International Business Machines Corporation | Carrier-resolved photo-hall system and method |
-
1986
- 1986-12-02 US US06/937,158 patent/US4755049A/en not_active Expired - Fee Related
-
1987
- 1987-09-30 KR KR870010951A patent/KR880008417A/en not_active Application Discontinuation
- 1987-11-19 JP JP62293041A patent/JPS63151042A/en active Granted
- 1987-11-25 CA CA000552742A patent/CA1262291A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| KR880008417A (en) | 1988-08-31 |
| JPH0318340B2 (en) | 1991-03-12 |
| JPS63151042A (en) | 1988-06-23 |
| US4755049A (en) | 1988-07-05 |
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