Patent US3905162A successfully refreshed from Google Patents.
US3905162A
Expired / Lapsed
US
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Method of preparing high yield semiconductor wafer
Assignee: Silicon Materials Inc
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Filing: 1974-07-23
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Granted: 1975-09-16
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Expires: 1994-07-23
Abstract
Abstract The method of preparing a semiconductor wafer introduces a controlled amount and distribution of lattice damage to the wafers prior to product fabrication processing steps. Semiconductor product performance characteristics improve when excess vacancies and contaminant impurities are drawn away from the pattern side of a wafer to affix themselves to the lattice damage on the reverse side of the wafer. The method includes applying an abrasive material to the backside of a rotating wafer to form a substantially circular pattern of lattice damage. The resultant distribution of lattice damage retards wafer warpage and breakage. The method lends itself to preparing virgin wafers and reclaiming used semicondcutor wafers.
Inventors
- 👤 John E Lawrence
- 👤 Jules C Santoro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:29
CPC Classifications
H; H10; H10P; H10P90/00; H10P90/12; H10P90/124; B; B24; B24B; B24B1/00; B28; B28D; B28D5/00; H10P50/00; Y; Y10; Y10S; Y10S117/00; Y10S117/913; Y10S148/00; Y10S148/138; Y10S438/00; Y10S438/938; Y10S438/974
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
61 words
A method of preparing a semiconductor wafer prior to device fabrication comprising the steps of: rotating a wafer in the plane of one of its faces; wetting said one face with a liquid lubricant; grinding a substantially circular pattern of lattice damage on said one face; and polishing the other face of said wafer to form a substantially strain-free mirror-like surface.
Claim 2
Independent Claim
61 words
A method of preparing a semiconductor wafer prior to device fabrication comprising the steps of: rotating a wafer in the plane of one of its faces; wetting said one face with a liquid lubricant; grinding a substantially circular pattern of lattice damage on said one face; and polishing the other face of said wafer to form a substantially strain-free mirror-like surface.
Claim 3
Dependent Claim
30 words
A method of preparing a semiconductor wafer prior to device fabrication as recited in claim 1 wherein the step of grinding includes depressing an abrasive material against said one face.
Claim 4
Dependent Claim
39 words
A method of preparing a semiconductor wafer prior to device fabrication as recited in claim 2 wherein said one face is wetted with deionized water prior to, during, and after the abrasive material is depressed against said one face.
Claim 5
Dependent Claim
27 words
A method of preparing a semiconductor wafer prior to device fabrication as recited in claim 2 wherein said abrasive material has a grit size of about 600.
Claim 6
Dependent Claim
34 words
A method of preparing a semiconductor wafer prior to device fabrication as recited in claim 2 wherein at least 5 micrometers of said wafer are removed from said one face during said grinding step.
Claim 7
Dependent Claim
32 words
A method of preparing a semiconductor wafer prior to device fabrication as recited in claim 2 wherein said wafer is rotated at a speed of between 1,000 and 1,500 revolutions per minute.
Claim 8
Dependent Claim
33 words
A methid of preparing a semiconductor wafer prior to device fabrication as recited in claim 3 wherein following termination of the grinding step said wafer is rotated until said one face is dry.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-15 | 1979-03-17 | 1979-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-15 | 1983-03-17 | 1983-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-15 | 1987-03-17 | 1987-09-16 | $7700.00 | Window Closed / Lapsed |