US5942445A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing semiconductor wafers
Assignee: Shin-Etsu Handotai Co Ltd
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Filing: 1997-03-25
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Granted: 1999-08-24
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Expires: 2017-03-25
Abstract
Abstract According to the invention, the flatness and quality can be improved while simplifying the process even when large size wafers of 200 to 300 mm or above are processed. Basic steps involved are a slicing step E for obtaining thin disc-shape wafers by slicing, a chamfering step F for chamfering the sliced wafers, a flattening step G for flattening the chamfered wafers, an alkali etching step H for removing process damage layers from the flattened wafers, and a double-side polishing step K of simultaneously polishing the two sides of the etched wafers. If necessary, a plasma etching step is used in lieu of the flattening and etching steps G and H respectively.
Inventors
- 👤 Tadahiro Kato
- 👤 Hisashi Masumura
- 👤 Sadayuki Okuni
- 👤 Hideo Kudo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:48
CPC Classifications
H; H10; H10P; H10P90/00; H10P90/12; H10P90/123; C; C30; C30B; C30B33/00; H10P90/126
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
32 words
A method of manufacturing a semiconductor wafer comprising the steps of: flattening a thin disc-shaped wafer obtained right after slicing by surface grinding, and polishing the flattened wafer on both sides simultaneously.
Claim 2
Independent Claim
32 words
A method of manufacturing a semiconductor wafer comprising the steps of: flattening a thin disc-shaped wafer obtained right after slicing by surface grinding, and polishing the flattened wafer on both sides simultaneously.
Claim 3
Dependent Claim
16 words
A method according to claim 1, wherein the wafer is chamfered after slicing and before flattening.
Claim 4
Dependent Claim
34 words
A method according to claim 1, further comprising removing process damage layers from the flattened wafer while maintaining the flatness thereof by a etching process after the flattening step and before the polishing step.
Claim 5
Dependent Claim
35 words
A method according to claim 3, further comprising after said etching process, subjecting the wafer to further process damage layer removal by dry plasma etching before the simultaneous polishing of both sides of the wafer.
Claim 6
Dependent Claim
15 words
A method according to claim 4, wherein said plasma etching comprises is plasma-assisted chemical etching.
Claim 7
Dependent Claim
20 words
A method according to claim 3, wherein said etching process is a wet etching process with an alkali etching solution.
Claim 8
Dependent Claim
41 words
A method according to claim 1, wherein the wafer is flattened by surface grinding with wax or a wax-like adhesive interposed between a back surface of the wafer and a base plate surface against which the wafer is supported by suction.
Claim 9
Dependent Claim
61 words
A method according to claim 1, wherein the wafer is flattened by surface grinding a front surface of the wafer with a grindstone at a grindstone feed pressure; a back surface of the wafer is held chucked by negative chucking pressure, and the chucking pressure is reduced for surface grinding in a spark-out time when the grindstone feed pressure is reduced.
Claim 10
Dependent Claim
29 words
A method according to claim 1, wherein said surface grinding is effected by first grinding means for two-sided grinding and second grinding means for cup-shaped grindstone in-feed surface grinding.
Claim 11
Dependent Claim
32 words
A method according to claim 1, wherein the simultaneous polishing of both sides of the wafer is carried out with a polishing pad having an Asker C hardness of at least 80.
Claim 12
Independent Claim
55 words
A method of manufacturing a semiconductor wafer comprising the steps of: flattening a thin disc-shaped wafer obtained right after slicing by surface grinding or lapping; dry etching the flattened wafer using plasma to remove process damage layers from the flattened wafer and finely flatten the wafer, and polishing the flattened wafer on both sides simultaneously.
Claim 13
Independent Claim
55 words
A method of manufacturing a semiconductor wafer comprising the steps of: flattening a thin disc-shaped wafer obtained right after slicing by surface grinding or lapping; dry etching the flattened wafer using plasma to remove process damage layers from the flattened wafer and finely flatten the wafer, and polishing the flattened wafer on both sides simultaneously.
Claim 14
Dependent Claim
15 words
A method according to claim 11, wherein the wafer is chamfered-after slicing and before flattening.
Claim 15
Dependent Claim
41 words
A method according to claim 11, wherein the wafer is flattened by surface grinding with wax or a wax-like adhesive interposed between a back surface of the wafer and a base plate surface against which the wafer is supported by suction.
Claim 16
Dependent Claim
62 words
A method according to claim 11, wherein the wafer is flattened by surface grinding a front surface of the wafer with a grindstone at a grindstone feed pressure, while a back surface of the wafer is held chucked by negative chucking pressure, and the chucking pressure is reduced for surface grinding in a spark-out time when the grindstone feed pressure is reduced.
Claim 17
Dependent Claim
15 words
A method according to claim 11, wherein said plasma etching comprises is plasma-assisted chemical etching.
Claim 18
Dependent Claim
32 words
A method according to claim 11, wherein the simultaneous polishing of both sides of the wafer is carried out with a polishing pad having an Asker C hardness of at least 80.
Claim 19
Independent Claim
40 words
A method of manufacturing a semiconductor wafer comprising subjecting a thin disc-shaped wafer obtained right after slicing to plasma dry etching to remove process damage layers and flatten the wafer, and thereafter polishing the flattened wafer on both sides simultaneously.
Claim 20
Independent Claim
40 words
A method of manufacturing a semiconductor wafer comprising subjecting a thin disc-shaped wafer obtained right after slicing to plasma dry etching to remove process damage layers and flatten the wafer, and thereafter polishing the flattened wafer on both sides simultaneously.
Claim 21
Dependent Claim
17 words
A method according to claim 17, wherein the wafer is chamfered prior to said plasma dry etching.
Claim 22
Dependent Claim
15 words
A method according to claim 17, wherein said plasma etching comprises is plasma-assisted chemical etching.
Claim 23
Dependent Claim
32 words
A method according to claim 17, wherein the simultaneous polishing of both sides of the wafer is carried out with a polishing pad having an Asker C hardness of at least 80.
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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) | 2002-08-23 | 2003-02-22 | 2003-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-08-23 | 2007-02-22 | 2007-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-08-23 | 2011-02-22 | 2011-08-24 | $7700.00 | Window Closed / Lapsed |