US4891499A
Expired / Lapsed
US
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Method and apparatus for real-time wafer temperature uniformity control and slip-free heating in lamp heated single-wafer rapid thermal processing systems
Assignee: Texas Instruments Inc
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Filing: 1988-09-09
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Granted: 1990-01-02
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Expires: 2008-09-09
Abstract
Abstract A silicon semiconductor wafer (26) is placed in a vacuum chamber (12) device side (28) facedown. Laser beams of equal power are directed at an edge point (72) and a center point (74) of the wafer (26). The laser beams are reflected from the edge point (72) and the center point (74) into first and second infrared photo-detectors (40-42). A differential amplifier (44) evaluates the reflected laser beams for a power difference and signals a current source (82). Current source (82) heats a quartz ring (46) which surrounds the wafer (26). The quartz ring (46) passes the heat to the wafer (26) until the amplifier (44) no longer senses a power difference, which is indicative of an equal wafer surface temperature.
Inventors
- 👤 Mehrdad M. Moslehi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:45
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/04; H10P72/0431; H10P72/0436; F; F27; F27B; F27B17/00; F27B17/0016; F27B17/0025; G; G05; G05D; G05D23/00; G05D23/19; G05D23/27; H10P34/00; H10P34/40; H10P34/42; H10P34/422
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
98 words
Apparatus for controlling temperature uniformity of a semiconductor wafer in a single wafer rapid thermal processing reactor having a heating lamp module comprising: a first laser beam reflected from an edge point on the wafer; a first infrared photo-detector to receive said first laser beam; a second laser beam reflected from a center point on the wafer; a second infrared photo-detector to receive said second laser beam; a differential amplifier to evaluate output from said first and second photo-detectors; and a heating element proximate the wafer, responsive to said amplifier, to control the temperature uniformity of the wafer.
Claim 2
Dependent Claim
98 words
Apparatus for controlling temperature uniformity of a semiconductor wafer in a single wafer rapid thermal processing reactor having a heating lamp module comprising: a first laser beam reflected from an edge point on the wafer; a first infrared photo-detector to receive said first laser beam; a second laser beam reflected from a center point on the wafer; a second infrared photo-detector to receive said second laser beam; a differential amplifier to evaluate output from said first and second photo-detectors; and a heating element proximate the wafer, responsive to said amplifier, to control the temperature uniformity of the wafer.
Claim 3
Dependent Claim
26 words
The apparatus of claim 1, wherein said first and second laser beams are optically coupled to the wafer by light pipes passing through the lamp module.
Claim 4
Dependent Claim
15 words
The apparatus of claim 2, wherein said light pipes have a 1/16 inch inside diameter.
Claim 5
Dependent Claim
25 words
The apparatus of claim 1, further including light pipes passing through the lamp module to optically couple the wafer to said first and second photo-detectors.
Claim 6
Dependent Claim
15 words
The apparatus of claim 4, wherein said light pipes have a 1/16 inch inside diameter.
Claim 7
Dependent Claim
17 words
The apparatus of claim 1, further comprising a laser to emit said first and second laser beams.
Claim 8
Dependent Claim
13 words
The apparatus of claim 6, where said laser comprises a carbon monoxide laser.
Claim 9
Dependent Claim
13 words
The apparatus of claim 6, wherein said laser comprises a carbon dioxide laser.
Claim 10
Dependent Claim
15 words
The apparatus of claim 8, wherein said carbon dioxide laser further includes a frequency doubler.
Claim 11
Dependent Claim
18 words
The apparatus of claim 6, further including a beam splitter to form said first and second laser beams.
Claim 12
Dependent Claim
47 words
The apparatus of claim 1, further comprising: a power supply controller connected to said amplifier; and an adjustable current source connected to said power supply and said heating element to raise or lower the temperature of said heating element in response to said amplifier and said controller.
Claim 13
Dependent Claim
29 words
The apparatus of claim 1, wherein said heating element comprises: a quartz tube encircling the wafer; and a filament within said tube to generate heat responsive to said amplifier.
Claim 14
Dependent Claim
10 words
The apparatus of claim 12, wherein said filament comprises tungsten.
Claim 15
Dependent Claim
17 words
The apparatus of claim 1, further comprising a sapphire window between the lamp module and the wafer.
Claim 16
Dependent Claim
57 words
The apparatus of claim 1, further comprising: a third infrared photo-detector for receiving a transmitted portion of said first laser beam; a fourth infrared photo-detector for receiving a transmitted portion of said second laser beam; and a second differential amplifier to evaluate output from said third and fourth photo-detectors and to provide data to said heating element.
Claim 17
Dependent Claim
122 words
A wafer temperature controller for a silicon semiconductor wafer rapid thermal process reactor which utilizes a heating lamp module, comprising: a laser which produces a first and second laser beam, each said beam being of equal power and wavelength, said first beam striking an edge point on the wafer, and said second beam striking a center point on the wafer; a first infrared photo-detector for receiving said first laser beam reflected from the wafer; a second infrared photo-detector for receiving said second laser beam reflected from the wafer; a differential amplifier for evaluating any power variation between said reflected beams; and a heating element for adjusting the temperature of the wafer responsive to said amplifier such that the wafer temperature is controlled.
Claim 18
Dependent Claim
122 words
A wafer temperature controller for a silicon semiconductor wafer rapid thermal process reactor which utilizes a heating lamp module, comprising: a laser which produces a first and second laser beam, each said beam being of equal power and wavelength, said first beam striking an edge point on the wafer, and said second beam striking a center point on the wafer; a first infrared photo-detector for receiving said first laser beam reflected from the wafer; a second infrared photo-detector for receiving said second laser beam reflected from the wafer; a differential amplifier for evaluating any power variation between said reflected beams; and a heating element for adjusting the temperature of the wafer responsive to said amplifier such that the wafer temperature is controlled.
Claim 19
Dependent Claim
21 words
The apparatus of claim 16, wherein said laser further includes a beam splitter to produce said first and second laser beam.
Claim 20
Dependent Claim
13 words
The apparatus of claim 16, wherein said laser comprises a carbon monoxide laser.
Claim 21
Dependent Claim
14 words
The apparatus of claim 16, wherein said laser comprises a carbon dioxide gas laser.
Claim 22
Dependent Claim
15 words
The apparatus of claim 19, wherein said carbon dioxide laser futher comprises a frequency doubler.
Claim 23
Dependent Claim
57 words
The apparatus of claim 16, further comprising: a third infrared photo-detector for receiving a transmitted portion of said first laser beam; a fourth infrared photo-detector for receiving a transmitted portion of said second laser beam; and a second differential amplifier to evaluate output from said third and fourth photo-detectors and to provide data to said heating element.
Claim 24
Independent Claim
106 words
A method for controlling temperature uniformity of a semiconductor wafer in a single wafer rapid thermal processing reactor having a heating lamp module, comprising the steps of: reflecting a first laser beam from an edge point on the wafer; receiving said first laser beam with a first infrared photo-detector; reflecting a second laser beam from a center point on the wafer; receiving said second laser beam with a second infrared photo-detector; evaluating output from said first and second photo-detectors with a differential amplifier; and heating an edge of the wafer with a heating element responsive to said amplifier to control the temperature uniformity of the wafer.
Claim 25
Independent Claim
106 words
A method for controlling temperature uniformity of a semiconductor wafer in a single wafer rapid thermal processing reactor having a heating lamp module, comprising the steps of: reflecting a first laser beam from an edge point on the wafer; receiving said first laser beam with a first infrared photo-detector; reflecting a second laser beam from a center point on the wafer; receiving said second laser beam with a second infrared photo-detector; evaluating output from said first and second photo-detectors with a differential amplifier; and heating an edge of the wafer with a heating element responsive to said amplifier to control the temperature uniformity of the wafer.
Claim 26
Dependent Claim
31 words
The method of claim 22, wherein the step of reflecting comprises: aiming at least one laser at the wafer; and optically coupling said laser through the lamp module with the wafer.
Claim 27
Dependent Claim
25 words
The method of claim 22, further comprising the step of calibrating said amplifier by zeroing said amplifier with the wafer at a uniform ambient temperature.
Claim 28
Dependent Claim
30 words
The method of claim 22, wherein the step of receiving further includes optically coupling the wafer to said photo-detectors with a first and second light pipe through the lamp module.
Claim 29
Dependent Claim
23 words
The method of claim 22, wherein the step of evaluating comprises measuring a power difference between said first and second reflected laser beams.
Claim 30
Dependent Claim
33 words
The method of claim 22, wherein the step of heating comprises the steps of: generating a current from a current source; and heating a tungsten filament within said heating element with said current.
Claim 31
Independent Claim
106 words
A method for controlling a wafer temperature in a silicon semiconductor wafer rapid thermal process reactor which utilizes a heating lamp module, comprising the steps of: generating a first and a second laser beam of equal power; reflecting said first laser beam from an edge point on the wafer; reflecting said second laser beam from a center point on the wafer; detecting said reflected laser beams with first and second infrared photo-detectors; evaluating said reflected laser beams for a power difference with a differential amplifier; and heating an edge of the wafer with an element responsive to said amplifier such that the wafer temperature is controlled.
Claim 32
Independent Claim
106 words
A method for controlling a wafer temperature in a silicon semiconductor wafer rapid thermal process reactor which utilizes a heating lamp module, comprising the steps of: generating a first and a second laser beam of equal power; reflecting said first laser beam from an edge point on the wafer; reflecting said second laser beam from a center point on the wafer; detecting said reflected laser beams with first and second infrared photo-detectors; evaluating said reflected laser beams for a power difference with a differential amplifier; and heating an edge of the wafer with an element responsive to said amplifier such that the wafer temperature is controlled.
Claim 33
Dependent Claim
19 words
The method of claim 28, wherein the step of generating comprises directing a laser beam into a beam splitter.
Claim 34
Dependent Claim
26 words
The method of claim 28, wherein the step of reflecting further comprises optically coupling a laser with the wafer by light pipes through the heating module.
Claim 35
Dependent Claim
25 words
The method of claim 28, wherein the step of detecting comprises optically coupling the wafer and said photo-detectors with light pipes through the heating module.
Claim 36
Dependent Claim
39 words
The method of claim 28, wherein the step of heating an edge comprises the steps of: generating a current from a current source based on said step of evaluating; and heating a filament in said element with said current.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-01-01 | 1993-07-03 | 1994-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-01 | 1997-07-03 | 1998-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-01 | 2001-07-03 | 2002-01-02 | $7700.00 | Window Closed / Lapsed |