US5102231A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor wafer temperature measurement system and method
Assignee: Texas Instruments Inc
•
Filing: 1991-01-29
•
Granted: 1992-04-07
•
Expires: 2011-01-29
Abstract
Abstract A system for measuring the temperature of a semiconductor wafer 12 comprises a light source 14, a photodetector 20 which is operable to determine light intensity, and a mirror 18 in a predetermined fixed position from a beam splitter 16. The components are positioned such that light from the light source 14 impinges the beam splitter 16 and subsequently reflects off the mirror 18 and the wafer 12 and is received by the photodetector 20. Changes in the temperature of the wafer 12 are calculated based upon changes in the intensity of the received light which depends upon the expansion/contraction of the wafer. The absolute temperature may be calculated based on a known reference temperature and the changes in wafer 12 temperature. A second system and method for measuring the temperature of a semiconductor wafer which includes the use of a plurality of mirrors and two beam splitters is also disclosed.
Inventors
- 👤 Lee M. Loewenstein
- 👤 John D. Lawrence
- 👤 Wayne G. Fisher
- 👤 Cecil J. Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:23
CPC Classifications
G; G01; G01K; G01K5/00; G01K5/48; G01K5/50; G01K5/52
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
145 words
A system to measure changes in the temperature of a semiconductor wafer comprising: a semiconductor wafer in a first position from a beam splitter; a light source; a photodetector operable to determine light intensity; a mirror in a predetermined substantially fixed position from said beam splitter; said beam splitter positioned such that light from said light source impinges said beam splitter so as to direct light to both of said mirror and said wafer such that said directed light is reflected off of said mirror and off of said wafer and is subsequently received by said photodetector, and such that the intensity of said received light depends substantially upon the expansion/contraction of said wafer with respect to said first position; and means for calculating a change in the temperature of said wafer based on the intensity of said received light as determined by said photodetector.
Claim 2
Independent Claim
145 words
A system to measure changes in the temperature of a semiconductor wafer comprising: a semiconductor wafer in a first position from a beam splitter; a light source; a photodetector operable to determine light intensity; a mirror in a predetermined substantially fixed position from said beam splitter; said beam splitter positioned such that light from said light source impinges said beam splitter so as to direct light to both of said mirror and said wafer such that said directed light is reflected off of said mirror and off of said wafer and is subsequently received by said photodetector, and such that the intensity of said received light depends substantially upon the expansion/contraction of said wafer with respect to said first position; and means for calculating a change in the temperature of said wafer based on the intensity of said received light as determined by said photodetector.
Claim 3
Dependent Claim
43 words
The system of claim 1 and further comprising means for determining a reference temperature at a point in time so that the absolute temperature of said wafer may be determined from said reference temperature and said change in the temperature of said wafer.
Claim 4
Dependent Claim
19 words
The system of claim 1 wherein said wafer is positioned to reflect light from the edge of said wafer.
Claim 5
Dependent Claim
12 words
The system of claim 1 wherein said light source comprises a laser.
Claim 6
Dependent Claim
11 words
The system of claim 1 wherein said semiconductor wafer comprises silicon.
Claim 7
Dependent Claim
13 words
The system of claim 1 and further comprising means for securing said wafer.
Claim 8
Dependent Claim
16 words
The system of claim 1 and further comprising means for recording said changes in wafer temperature.
Claim 9
Dependent Claim
18 words
The system of claim 7 and further comprising means for controlling a process based on said wafer temperature.
Claim 10
Independent Claim
208 words
A system to measure the temperature of a semiconductor wafer comprising: a semiconductor wafer in a first position from first and second beam splitters; a light source; a photodetector operable to determine light intensity; a plurality of mirrors each in a predetermined, substantially fixed position from said first and second beam splitters; and said first and second beam splitter positioned such that a first portion of light from said light source impinges said first beam splitter and is directed toward and reflected from a first position on said wafer and then subsequently reflects off said mirrors and impinges said second beam splitter and reflects off a second position on said wafer and subsequently is received by said photodetector, and simultaneously a second portion of light from said light source impinges said first beam splitter and is directed by other ones of said mirrors and said second beam splitter so as to be received by said photodetector, such that the intensity of said light received by said photodetector depends substantially upon the expansion/contraction of said wafer with respect to said first position; and circuitry for calculating a change in the temperature of the wafer based a change in the intensity of said first and second portions of received light.
Claim 11
Independent Claim
208 words
A system to measure the temperature of a semiconductor wafer comprising: a semiconductor wafer in a first position from first and second beam splitters; a light source; a photodetector operable to determine light intensity; a plurality of mirrors each in a predetermined, substantially fixed position from said first and second beam splitters; and said first and second beam splitter positioned such that a first portion of light from said light source impinges said first beam splitter and is directed toward and reflected from a first position on said wafer and then subsequently reflects off said mirrors and impinges said second beam splitter and reflects off a second position on said wafer and subsequently is received by said photodetector, and simultaneously a second portion of light from said light source impinges said first beam splitter and is directed by other ones of said mirrors and said second beam splitter so as to be received by said photodetector, such that the intensity of said light received by said photodetector depends substantially upon the expansion/contraction of said wafer with respect to said first position; and circuitry for calculating a change in the temperature of the wafer based a change in the intensity of said first and second portions of received light.
Claim 12
Dependent Claim
39 words
The system of claim 9 and further comprising means for determining the absolute temperature at a point in time so that said means for calculating a change in temperature comprises means for calculating the absolute temperature of said wafer.
Claim 13
Dependent Claim
19 words
The system of claim 9 wherein said wafer is positioned to reflect light from the edge of said wafer.
Claim 14
Dependent Claim
29 words
The system of claim 11 wherein said mirrors and said wafer are positioned such that said first portion of light reflects off two diametrically opposed points on said wafer.
Claim 15
Dependent Claim
12 words
The system of claim 9 wherein said light source comprises a laser.
Claim 16
Dependent Claim
13 words
The system of claim 9 and further comprising means for securing said wafer.
Claim 17
Independent Claim
154 words
A method for measuring a change in the temperature of a semiconductor wafer comprising: providing a semiconductor wafer in a first position from a beam splitter; shining light at said beam splitter which splits said light into a first and second beam wherein said first beam travels toward said wafer and said second beam travels towards a predetermined, substantially fixed position mirror; reflecting said first beam from a first position of said wafer and reflecting said second beam from said mirror such that said first and second reflected beams travel towards a photodetector operable to determine light intensity and wherein the intensity of said first and second reflected beams depends substantially upon the expansion/contraction of said wafer with respect to said first position; receiving said first and second reflected beams at said photodetector; and calculating a change in the temperature of said wafer based on the intensity of said first and second received beams.
Claim 18
Independent Claim
154 words
A method for measuring a change in the temperature of a semiconductor wafer comprising: providing a semiconductor wafer in a first position from a beam splitter; shining light at said beam splitter which splits said light into a first and second beam wherein said first beam travels toward said wafer and said second beam travels towards a predetermined, substantially fixed position mirror; reflecting said first beam from a first position of said wafer and reflecting said second beam from said mirror such that said first and second reflected beams travel towards a photodetector operable to determine light intensity and wherein the intensity of said first and second reflected beams depends substantially upon the expansion/contraction of said wafer with respect to said first position; receiving said first and second reflected beams at said photodetector; and calculating a change in the temperature of said wafer based on the intensity of said first and second received beams.
Claim 19
Dependent Claim
50 words
The method of claim 15 and further comprising the step of measuring a reference temperature of said wafer prior to calculating a change in the temperature so that the absolute temperature of said wafer may be determined from said reference temperature and said change in the temperature of said wafer.
Claim 20
Dependent Claim
27 words
The method of claim 15 wherein said step of reflecting said first beam comprises reflecting said first beam from a position of the side of said wafer.
Claim 21
Dependent Claim
21 words
The method of claim 17 and further comprising the step of polishing the side of said wafer prior to reflecting light.
Claim 22
Dependent Claim
22 words
The method of claim 15 and further comprising the step of recording the temperature of said wafer subsequent to calculating the temperature.
Claim 23
Independent Claim
165 words
A method for measuring a change in the temperature of a semiconductor wafer comprising: providing a semiconductor wafer in a first position from first and second beam splitters; shining light at said first beam splitter which splits said light into a first and second beam wherein said first beam travels toward and reflects from a first position on said wafer and subsequently reflects off of at least one mirror and impinges said second beam splitter and reflects off of a second position on said wafer and is directed towards a photodetector, and simultaneously said second beam travels towards at least one predetermined, substantially fixed position mirror and is subsequently reflected towards said photodetector; receiving said first and second reflected beams at said photodetector wherein the intensisty of said received beams depends substantially upon the expansion/contraction of said wafer with respect to said first position; and calculating a change in the temperature of said wafer based on the intensity of said first and second received beams.
Claim 24
Independent Claim
165 words
A method for measuring a change in the temperature of a semiconductor wafer comprising: providing a semiconductor wafer in a first position from first and second beam splitters; shining light at said first beam splitter which splits said light into a first and second beam wherein said first beam travels toward and reflects from a first position on said wafer and subsequently reflects off of at least one mirror and impinges said second beam splitter and reflects off of a second position on said wafer and is directed towards a photodetector, and simultaneously said second beam travels towards at least one predetermined, substantially fixed position mirror and is subsequently reflected towards said photodetector; receiving said first and second reflected beams at said photodetector wherein the intensisty of said received beams depends substantially upon the expansion/contraction of said wafer with respect to said first position; and calculating a change in the temperature of said wafer based on the intensity of said first and second received beams.
Claim 25
Dependent Claim
22 words
The method of claim 20 wherein said second position on said wafer is diametrically opposed to said first position on said wafer.
References Cited (Backward Citations)
US3632212A
Cited
US4375164A
Cited
US4818102A
Cited
US4918492A
Cited
US4841150A
Cited
US4919542A
Cited
US4979134A
Cited
US4973853A
Cited
US4948958A
Cited
US4984903A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-04-07 | 1995-10-07 | 1996-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-04-07 | 1999-10-07 | 2000-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-04-07 | 2003-10-07 | 2004-04-07 | $7700.00 | Window Closed / Lapsed |