US4462188A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silica sol compositions for polishing silicon wafers
Assignee: DuPont Electronic Materials Holding Inc
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Filing: 1982-06-21
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Granted: 1984-07-31
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Expires: 2002-06-21
Abstract
Abstract Semi-conductors can be polished with greater efficiency using as a polishing agent a blend of colloidal silica or silica gel, a water-soluble amine and a water-soluble quaternary ammonium salt or base.
Inventors
- 👤 Charles C. Payne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:25
CPC Classifications
H; H10; H10P; H10P52/00; H10P52/40; H10P52/402
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
54 words
An improved method for polishing silicon wafers and like materials which comprises applying a polishing agent comprising: 1. An aqueous colloidal silica sol or gel having an average particle size diameter in the range 4-100 millimicrons, 2. A water-soluble amine which contains at least 1 primary amino group and from 2-8 carbon atoms and,
Claim 2
Dependent Claim
54 words
An improved method for polishing silicon wafers and like materials which comprises applying a polishing agent comprising: 1. An aqueous colloidal silica sol or gel having an average particle size diameter in the range 4-100 millimicrons, 2. A water-soluble amine which contains at least 1 primary amino group and from 2-8 carbon atoms and,
Claim 3
Dependent Claim
48 words
A water-soluble quaternary ammonium salt or base containing not more than 6 carbon atoms, and wherein both the amine and the quarternary ammonium salt or base is present at from 0.1-5.0% by weight based on the SiO 2 content of the silica sol; and then, polishing said wafers.
Claim 4
Dependent Claim
48 words
A water-soluble quaternary ammonium salt or base containing not more than 6 carbon atoms, and wherein both the amine and the quarternary ammonium salt or base is present at from 0.1-5.0% by weight based on the SiO 2 content of the silica sol; and then, polishing said wafers.
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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) | 1987-07-31 | 1988-01-30 | 1988-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-31 | 1992-01-30 | 1992-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-31 | 1996-01-30 | 1996-07-31 | $7700.00 | Window Closed / Lapsed |