US4756796A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing wafer
Assignee: Mitsubishi Materials Silicon Corp
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Filing: 1986-10-10
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Granted: 1988-07-12
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Expires: 2006-10-10
Abstract
Abstract There is disclosed a method of providing an elongated stock; producing a wafer comprising the steps of processing one end face of an elongated stock to form a first flat surface; cutting through one end portion of the stock transversely by a cutter to provide a slice of a predetermined thickness having opposite side faces defined respectively by the first flat surface and a cut surface subjected to the cutting; and processing the cut surface of the slice to form a second flat surface, using the first flat surface as a reference surface, thereby providing the wafer.
Inventors
- 👤 Yuichi Saitou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:25
CPC Classifications
C; C30; C30B; C30B33/00; B; B28; B28D; B28D1/00; B28D1/003; B28D5/00; B28D5/0058; B28D5/0082; B28D5/0094; C30B25/00; C30B25/02; C30B25/18; Y; Y10; Y10S; Y10S438/00; Y10S438/959
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
155 words
A method for producing two or more wafers from an elongated stock whose length is many times greater than the thickness of each wafer, comprising the steps of: (a) providing an elongated stock having an end face with a warped surface due to a prior wafer slicing operation; (b) milling said one end face to remove stock material and to reduce the warp of the surface to form a flat end surface on said stock; (c) cutting transversely through said elongated stock adjacent said one end surface by a cutter to provide a slice of a predetermined thickness having opposite side faces defined respectively by said first flat surface and a cut surface created by said cutting step; (d) milling said cut surface of said slice to form a second flat surface, using said first flat surface as a reference surface to align said second flat surface, thereby providing the wafer with two flat surfaces.
Claim 2
Independent Claim
155 words
A method for producing two or more wafers from an elongated stock whose length is many times greater than the thickness of each wafer, comprising the steps of: (a) providing an elongated stock having an end face with a warped surface due to a prior wafer slicing operation; (b) milling said one end face to remove stock material and to reduce the warp of the surface to form a flat end surface on said stock; (c) cutting transversely through said elongated stock adjacent said one end surface by a cutter to provide a slice of a predetermined thickness having opposite side faces defined respectively by said first flat surface and a cut surface created by said cutting step; (d) milling said cut surface of said slice to form a second flat surface, using said first flat surface as a reference surface to align said second flat surface, thereby providing the wafer with two flat surfaces.
Claim 3
Dependent Claim
26 words
A method according to claim 1, in which the wafer is subjected to stress-relieving annealing to improve the flatness of said first and second flat surface.
Claim 4
Dependent Claim
30 words
A method according to claim 1 wherein the step (b) of milling the end face of the stock comprises mechanically abrading said surface to remove stock and flatten said surface.
Claim 5
Dependent Claim
30 words
A method according to claim 1 wherein the step (b) of milling the end face of the stock comprises mechanically grinding said surface to remove stock and flatten said surface.
Claim 6
Dependent Claim
30 words
A method according to claim 1 wherein the step (b) of milling the end face of the stock comprises mechanically cutting said surface to remove stock and flatten said surface.
References Cited (Backward Citations)
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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) | 1991-07-12 | 1992-01-11 | 1992-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-12 | 1996-01-11 | 1996-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-12 | 2000-01-11 | 2000-07-12 | $7700.00 | Window Closed / Lapsed |