US20070296948A1 - Dose transfer standard detector for a lithography tool - Google Patents
Dose transfer standard detector for a lithography tool Download PDFInfo
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- US20070296948A1 US20070296948A1 US11/894,791 US89479107A US2007296948A1 US 20070296948 A1 US20070296948 A1 US 20070296948A1 US 89479107 A US89479107 A US 89479107A US 2007296948 A1 US2007296948 A1 US 2007296948A1
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- United States
- Prior art keywords
- radiation
- detector
- wafer
- amount
- processor
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
- G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
- G03F7/7055—Exposure light control in all parts of the microlithographic apparatus, e.g. pulse length control or light interruption
- G03F7/70558—Dose control, i.e. achievement of a desired dose
Definitions
- FIG. 1 illustrates an example of a lithography tool, such as an Extreme Ultraviolet lithography (EUVL) tool.
- EUVL Extreme Ultraviolet lithography
- the detectors 206 in FIG. 2 may be adapted to detect radiation intensity (milliWatts/cm 2 ) incident upon the wafer 201 and/or dose (milliJoules/cm 2 ) when the wafer 201 is in the lithography tool 100 .
- the detectors 206 may include photodiodes.
- the detectors 206 may include a silicon photodiode.
- the detectors 206 may detect extreme ultraviolet (EUV) radiation and other types of radiation.
- An array of detectors 206 may be used since intensity and/or dose may vary (e.g., 0.5%) over multiple detectors. An average intensity and/or dose over multiple detectors may be calculated in an embodiment.
- the computer 304 may analyze the dose and/or intensity data from the detector structure 200 at 402 .
- the computer 304 may collect and analyze data remotely.
- the computer 304 or a user using data from the computer 302 , may compare the dose and/or intensity data from the detector structure 200 to a reference, such as a user-defined setting on the first lithography tool 302 A.
- the computer 304 or a user may determine if the detected dose and/or intensity substantially matches the reference.
Abstract
A dose transfer standard detector measures radiation intensity and dose in a lithography tool. The lithography tool may be an Extreme Ultraviolet lithography (EUVL) tool. The dose transfer standard detector may transmit intensity and dose data to a computer, which analyzes the data. Based on the analyzed data, the lithography tool may be calibrated.
Description
- This application is a continuation application of and claims priority under 35 U.S.C. §120 to U.S. application Ser. No. 10/661,971, filed on Sep. 11, 2003.
- A microchip manufacturing process may deposit various material layers on a wafer and form a photosensitive film or photoresist on one or more deposited-layers. A lithography tool may transmit light through transmissive optics or reflect light from reflective optics to a reticle or patterned mask. Light from the reticle transfers a patterned image onto the photoresist. Portions of the photoresist which are exposed to light may be removed. Portions of the wafer which are not protected by the remaining photoresist may be etched to form transistor features.
- The semiconductor industry may continue to reduce the size of transistor features to increase transistor density and improve transistor performance. This reduction in transistor feature size has driven a reduction in the wavelength of light used in lithography tools to define smaller transistor features on a photoresist.
-
FIG. 1 illustrates an example of a lithography tool, such as an Extreme Ultraviolet lithography (EUVL) tool. -
FIG. 2 illustrates a dose transfer standard detector structure which may be used in the lithography tool ofFIG. 1 . -
FIG. 3 illustrates the dose transfer standard detector structure ofFIG. 2 , two lithography tools and a computer. -
FIG. 4 shows a flow chart of using the dose transfer standard detector ofFIG. 2 . -
FIG. 5 illustrates an alternative embodiment of the dose transfer standard detector structure ofFIG. 2 . - Extreme Ultraviolet lithography (EUVL) may use a radiation wavelength of approximately 11-15 nanometers (nm). An EUV lithography tool may print a pattern on a photoresist with dimensions which are smaller than dimensions achieved by other lithography tools. An EUV lithography tool may also be called a “lithographic exposure system,” an “EUV scanner” or an “EUV stepper.”
-
FIG. 1 illustrates an example of alithography tool 100, such as an Extreme Ultraviolet lithography (EUVL) tool. Thelithography tool 100 may include alaser 102, an electric discharge or laser producedplasma source 104,condenser optics 106, areflective reticle 107 with a pattern, andreflective reduction optics 108. Thereticle 107 may be used to form a patterned image on anobject 110, such as a silicon wafer with a photoresist layer. - “Intensity” (milliWatts/cm2) refers to an amount of radiation incident upon the
object 110 in thelithography tool 100. “Dose” (milliJoules/cm2) refers to an amount of energy absorbed by theobject 110 in thelithography tool 100. A user may set radiation intensity and dose for a lithography tool according to a standard reference. The standard reference may be based on values provided by the National Institute of Standards & Technology (NIST). The intensity and dose may vary slightly from lithography tool to lithography tool even though the lithography tools have the same settings. Intensity and dose may also change (“drift”) after a lithography tool is shipped or after repeated used. - It may be desirable to measure and calibrate the intensity and dose of a lithography tool. It may be desirable to compare and match the intensity and dose of two or more lithography tools.
- It may be difficult to access a wafer stage of a conventional lithography tool to install hardware to measure radiation intensity and dose. A lithography tool may have a vacuum or non-vacuum wafer stage. For a lithography tool with a non-vacuum wafer stage, a person may enter the lithography tool and manually connect radiation detection hardware to the wafer stage.
- For a lithography tool with a wafer stage in a vacuum, such as an EUV lithography tool, a person may have to break the vacuum to install radiation detection hardware to the wafer stage. Alternatively, a robot may be inserted in an interlock chamber connected to the vacuum to insert radiation detection hardware to the wafer stage.
- The present application relates to a dose transfer (or dose transport) standard detector and techniques of using the same. The detector may address the challenges of moving a dose detector between two or more lithography tools. The detector may be easily loaded and unloaded on a wafer stage of a lithography tool, such as an extreme ultraviolet lithography (EUVL) tool. The detector may accurately measure the intensity and/or dose of one or more-vacuum or non-vacuum lithography tools. The size, shape and components of the detector may automate loading of the detector, alignment of the detector, and collection of intensity and dose data. A computer may compare data from the detector with a reference value.
-
FIG. 2 illustrates a dose transferstandard detector structure 200, which may be used in thelithography tool 100 ofFIG. 1 . Lithography tools may handle the dose transferstandard detector structure 200 as any other wafer. Thedetector structure 200 may include awafer 201 fabricated with an array ofdetectors 206, one ormore amplifiers 202, aprocessor 203, awireless transmitter 204, apower source 207 andalignment marks 205. - The
processor 203 inFIG. 2 may be a digital signal processor available from Intel Corporation. Thepower source 207 inFIG. 2 may be capacitive, electrolytic, photovoltaic or some other type of power source. Thealignment marks 205 allow thewafer 201 to be aligned on a wafer stage of thelithography tool 100. - The
detectors 206 inFIG. 2 may be adapted to detect radiation intensity (milliWatts/cm2) incident upon thewafer 201 and/or dose (milliJoules/cm2) when thewafer 201 is in thelithography tool 100. Thedetectors 206 may include photodiodes. For example, thedetectors 206 may include a silicon photodiode. Thedetectors 206 may detect extreme ultraviolet (EUV) radiation and other types of radiation. An array ofdetectors 206 may be used since intensity and/or dose may vary (e.g., 0.5%) over multiple detectors. An average intensity and/or dose over multiple detectors may be calculated in an embodiment. - The temperature of the wafer stage inside the
lithography tool 100 may be carefully controlled such that thedetectors 206,amplifiers 202,processor 203,wireless transmitter 204, andpower source 207 on thewafer 201 do not experience a substantial temperature change. The array ofdetectors 206 may be the only components on thewafer 201 exposed to radiation in thelithography tool 100 in an embodiment. -
FIG. 3 illustrates the dose transferstandard detector structure 200 ofFIG. 2 being used with first andsecond lithography tools computer 304. Thelithography tools lithography tool 100 ofFIG. 1 . -
FIG. 4 shows a flow chart for using the dose transferstandard detector structure 200 ofFIG. 2 . Thedetector structure 200 may be loaded and aligned on a wafer stage of thefirst lithography tool 302A (FIG. 3 ) at 400 inFIG. 4 . Thefirst lithography tool 302A may be activated to produce radiation on thedetectors 206 of thewafer 201. The array ofdetectors 206 may detect a radiation dose and/or intensity and produce one or more signals. One ormore amplifiers 202 may amplify signals from thedetectors 206. Theprocessor 203 may process or convert amplified signals from theamplifiers 202 to a form which may be transmitted by thetransmitter 204. Thetransmitter 204 may wirelessly transmit signals corresponding to dose and/or intensity data to the computer 304 (FIG. 3 ) while thedetector structure 200 is inside thefirst lithography tool 302A. - In alternative embodiment, the
detector structure 200 stores dose and/or intensity data in anoptional memory 210. When thedetector structure 200 comes out of thefirst lithography tool 302A, thedetector structure 200 may transfer dose and/or intensity data in thememory 210 to thecomputer 304 wirelessly or via a physical output connector. - The
computer 304 may analyze the dose and/or intensity data from thedetector structure 200 at 402. Thecomputer 304 may collect and analyze data remotely. Thecomputer 304, or a user using data from the computer 302, may compare the dose and/or intensity data from thedetector structure 200 to a reference, such as a user-defined setting on thefirst lithography tool 302A. Thecomputer 304 or a user may determine if the detected dose and/or intensity substantially matches the reference. - If the
computer 304, or a user using the computer 302, determines that the detected dose and/or intensity does not substantially match the reference, thecomputer 304 or user may adjust settings or calibrations of thefirst lithography tool 302A at 404. For example, thefirst lithography tool 302A may be set to produce a desired dose of 10 milliJoules/cm2 (e.g., by calibrating thelaser 102 inFIG. 1 ). But thedetector structure 200 loaded in thefirst lithography tool 302A detects an actual dose of 9.5 milliJoules/cm2. Thecomputer 304, or a user using the computer 302, may adjust thefirst lithography tool 302A to 10.5 milliJoules/cm2. Thefirst lithography tool 302A may then produce an actual dose of 10 milliJoules/cm2. - The actions described above at 400 through 404 may be repeated to achieve a desired level of accuracy for dose and/or intensity of the
first lithography tool 302A. - If the
computer 304, or a user using the computer 302, determines that the detected dose and/or intensity does substantially match the reference, the dose transferstandard detector structure 200 may be loaded and aligned on a wafer stage of thesecond lithography tool 302B at 406. Thedetector structure 200 may measure dose and/or intensity of thesecond lithography tool 302B. Thecomputer 304 or a user may adjust the second lithography tool's calibration based on the measured dose and/or intensity. The actions described above at 400-404 may be repeated for thesecond lithography tool 302B and other lithography tools. - Thus, the
detector structure 200 andcomputer 304 may be used to calibrate two or more lithography tools. Thedetector structure 200 andcomputer 304 may be used to match intensity and dose of two or more lithography tools. -
FIG. 5 illustrates an alternative embodiment of a dose transferstandard detector structure 500. Thedetector structure 500 may have detectors, amplifiers and alignment marks which are substantially similar to thedetectors 206,amplifiers 202 and alignment marks 205 of thedetector structure 200 inFIG. 2 . Thedetector structure 500 may be inserted in alithography tool 502. Thelithography tool 502 may have sensors or probes 504 which contact thedetector structure 500 to establish an electrical connection and read intensity and/or dose data from thedetector structure 500. - A number of embodiments have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the application. For example, the structures and techniques described above may be used to measure and calibrate intensity and does for other lithography tools besides EUV lithography tools. Accordingly, other embodiments are within the scope of the following claims.
Claims (22)
1. An apparatus comprising:
a wafer adapted to fit on a wafer stage of a lithography tool, the wafer comprising
a radiation detector to produce a signal corresponding to an amount of radiation incident on the radiation detector,
a processor in communication with the radiation detector to receive the signal, the processor to process the signal from the radiation detector, and
a wireless transmitter in communication with the processor to receive results of processing the signal and output a wireless signal based on the results.
2. The apparatus of claim 1 , wherein the detector is adapted to detect a dose of radiation.
3. The apparatus of claim 1 , wherein the detector is adapted to detect an intensity of radiation.
4. The apparatus of claim 1 , wherein the wafer comprising comprises an array of detectors that includes the detector.
5. The apparatus of claim 1 , wherein the wafer further comprises alignment marks.
6. The apparatus of claim 1 , wherein the wafer further comprises an amplifier in communication with the radiation detector and the processor, the amplifier to amplify the signal from the radiation detector and communicate the amplified signal to the processor.
7. The apparatus of claim 1 , wherein the wafer further comprises a power source in communication with the processor to provide power to the processor.
8. The apparatus of claim 1 , wherein the wafer further comprises a memory electrically coupled to the processor, the memory to store data received from the processor, the data resulting from the processing of the signal corresponding to an amount of radiation incident on the radiation detector.
9. An apparatus comprising:
a wafer substrate sized to fit on a wafer stage of a lithography tool;
a radiation detector fabricated on the wafer substrate, the radiation detector to produce a signal indicative of an amount of radiation incident on the radiation detector;
a processor attached to the wafer substrate, the processor electrically coupled to the radiation detector, the processor to process the signal indicative of the amount of radiation incident on the radiation detector; and
a wireless transmitter fabricated on the wafer substrate, the wireless transmitter in communication with the processor to receive results of processing the signal and output a wireless signal based on the results.
10. The apparatus of claim 9 , further comprising a memory to store the results of processing the signal after receipt from the processor.
11. A method comprising:
loading a wafer-shaped detector onto a wafer stage of a first lithography tool;
detecting an amount of radiation from the first lithography tool that is incident on the wafer-shaped detector; and
wirelessly transmitting a first signal indicative of the amount of radiation incident on the wafer-shaped detector to a remote receiver.
12. The method of claim 11 , further comprising aligning the wafer-shaped detector on the wafer stage.
13. The method of claim 11 , further comprising converting a signal indicative of the amount of radiation incident on the wafer-shaped detector to the first signal.
14. The method of claim 11 , wherein said detecting the amount of radiation comprises measuring a dose of radiation.
15. The method of claim 11 , wherein said detecting the amount of radiation comprises measuring an intensity of radiation.
16. The method of claim 11 , further comprising amplifying an output from the detector.
17. The method of claim 11 , further comprising removing the wafer-shaped detector from the wafer stage.
18. The method of claim 11 , further comprising comparing the amount of radiation incident on the wafer-shaped detector to a pre-determined reference value.
19. The method of claim 18 , further comprising adjusting a setting of the lithography tool if the amount of radiation incident on the wafer-shaped detector does not substantially match the pre-determined reference value.
20. The method of claim 19 , further comprising repeatedly detecting an amount of radiation incident on the detector, and transmitting one or more second signals indicative of the amount of radiation detected by the repeated detections.
21. The method of claim 11 , further comprising:
loading the wafer-shaped detector onto a wafer stage of a second lithography tool;
detecting an amount of radiation from the second lithography tool that is incident on the wafer-shaped detector; and
wirelessly transmitting a second signal indicative of the amount of radiation incident on the wafer-shaped detector to the remote receiver.
22. The method of claim 21 , further comprising comparing the amount of radiation detected by the detector in the first lithography tool to the amount of radiation detected by the detector in the second lithography tool.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US11/894,791 US20070296948A1 (en) | 2003-09-11 | 2007-08-20 | Dose transfer standard detector for a lithography tool |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/661,971 US7326945B2 (en) | 2003-09-11 | 2003-09-11 | Dose transfer standard detector for a lithography tool |
US11/894,791 US20070296948A1 (en) | 2003-09-11 | 2007-08-20 | Dose transfer standard detector for a lithography tool |
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Application Number | Title | Priority Date | Filing Date |
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US10/661,971 Continuation US7326945B2 (en) | 2003-09-11 | 2003-09-11 | Dose transfer standard detector for a lithography tool |
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US20070296948A1 true US20070296948A1 (en) | 2007-12-27 |
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US10/661,971 Expired - Fee Related US7326945B2 (en) | 2003-09-11 | 2003-09-11 | Dose transfer standard detector for a lithography tool |
US11/894,791 Abandoned US20070296948A1 (en) | 2003-09-11 | 2007-08-20 | Dose transfer standard detector for a lithography tool |
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US10/661,971 Expired - Fee Related US7326945B2 (en) | 2003-09-11 | 2003-09-11 | Dose transfer standard detector for a lithography tool |
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US20090015814A1 (en) * | 2007-07-11 | 2009-01-15 | Carl Zeiss Smt Ag | Detector for registering a light intensity, and illumination system equipped with the detector |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4000502A (en) * | 1973-11-05 | 1976-12-28 | General Dynamics Corporation | Solid state radiation detector and process |
US4585342A (en) * | 1984-06-29 | 1986-04-29 | International Business Machines Corporation | System for real-time monitoring the characteristics, variations and alignment errors of lithography structures |
US5173609A (en) * | 1990-04-06 | 1992-12-22 | Thomson-Csf | Device for the detection of radiation that endangers living beings |
US5321269A (en) * | 1990-04-24 | 1994-06-14 | Hitachi, Ltd. | Neutron individual dose meter, neutron dose rate meter, neutron detector and its method of manufacture |
US20020102482A1 (en) * | 2000-12-08 | 2002-08-01 | Adlai Smith | Reference wafer and process for manufacturing same |
US20020134947A1 (en) * | 2000-12-22 | 2002-09-26 | Van Schaik Willem | Lithographic apparatus, device manufacturing method, and device manufactured thereby |
US6486476B1 (en) * | 1998-12-22 | 2002-11-26 | Hitachi, Ltd. | Semiconductor radiation detector and manufacture thereof |
US20030074097A1 (en) * | 2000-12-04 | 2003-04-17 | Motorola, Inc., Semiconductor 300 Gmbh & Co. Kg, And Infineon Technologies Ag. | Assembly comprising a plurality of mask containers, manufacturing system for manufacturing semiconductor devices, and method |
US20040058256A1 (en) * | 2002-07-03 | 2004-03-25 | Tadahito Fujisawa | Dose monitoring method and manufacturing method of semiconductor device |
-
2003
- 2003-09-11 US US10/661,971 patent/US7326945B2/en not_active Expired - Fee Related
-
2007
- 2007-08-20 US US11/894,791 patent/US20070296948A1/en not_active Abandoned
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4000502A (en) * | 1973-11-05 | 1976-12-28 | General Dynamics Corporation | Solid state radiation detector and process |
US4585342A (en) * | 1984-06-29 | 1986-04-29 | International Business Machines Corporation | System for real-time monitoring the characteristics, variations and alignment errors of lithography structures |
US5173609A (en) * | 1990-04-06 | 1992-12-22 | Thomson-Csf | Device for the detection of radiation that endangers living beings |
US5321269A (en) * | 1990-04-24 | 1994-06-14 | Hitachi, Ltd. | Neutron individual dose meter, neutron dose rate meter, neutron detector and its method of manufacture |
US6486476B1 (en) * | 1998-12-22 | 2002-11-26 | Hitachi, Ltd. | Semiconductor radiation detector and manufacture thereof |
US20030074097A1 (en) * | 2000-12-04 | 2003-04-17 | Motorola, Inc., Semiconductor 300 Gmbh & Co. Kg, And Infineon Technologies Ag. | Assembly comprising a plurality of mask containers, manufacturing system for manufacturing semiconductor devices, and method |
US20020102482A1 (en) * | 2000-12-08 | 2002-08-01 | Adlai Smith | Reference wafer and process for manufacturing same |
US20020134947A1 (en) * | 2000-12-22 | 2002-09-26 | Van Schaik Willem | Lithographic apparatus, device manufacturing method, and device manufactured thereby |
US20040058256A1 (en) * | 2002-07-03 | 2004-03-25 | Tadahito Fujisawa | Dose monitoring method and manufacturing method of semiconductor device |
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US20050057739A1 (en) | 2005-03-17 |
US7326945B2 (en) | 2008-02-05 |
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AS | Assignment |
Owner name: INTEL CORPORATION, CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:GOLDSTEIN, MICHAEL;REEL/FRAME:020195/0628 Effective date: 20030908 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- AFTER EXAMINER'S ANSWER OR BOARD OF APPEALS DECISION |