Patent US4964919A successfully refreshed from Google Patents.
US4964919A
Expired / Lapsed
US
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Cleaning of silicon wafers with an aqueous solution of KOH and a nitrogen-containing compound
Assignee: DuPont Electronic Materials Holding Inc
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Filing: 1988-12-27
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Granted: 1990-10-23
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Expires: 2008-12-27
Abstract
Abstract Composition of matter and method of cleaning silicon wafers; the composition of matter is an aqueous solution of potassium hydroxide and a nitrogen-containing compound, preferably tetramethylammonium hydroxide. The wafer is immersed in the solution, rinsed and dried.
Inventors
- 👤 Charles C. Payne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:07
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/04; H10P72/0402; H10P72/0406; H10P72/0411; H10P72/0416
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
40 words
A composition of matter for cleaning silicon IC wafers consisting essentially of an aqueous solution of about 10% by weight potassium hydroxide and 2.5% by weight of a nitrogen-containing compound selected from the group consisting of tetramethylammonium hydroxide and taurine.
Claim 2
Dependent Claim
40 words
A composition of matter for cleaning silicon IC wafers consisting essentially of an aqueous solution of about 10% by weight potassium hydroxide and 2.5% by weight of a nitrogen-containing compound selected from the group consisting of tetramethylammonium hydroxide and taurine.
Claim 3
Dependent Claim
26 words
A method of cleaning silicon wafers comprising the steps of immersing the wafer in a solution claimed in claim 1; afterwards rinsing and drying the wafer.
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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) | 1993-10-22 | 1994-04-23 | 1994-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-22 | 1998-04-23 | 1998-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-22 | 2002-04-23 | 2002-10-23 | $7700.00 | Window Closed / Lapsed |