Patent US4810669A successfully refreshed from Google Patents.
US4810669A
Expired / Lapsed
US
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Method of fabricating a semiconductor device
Assignee: Oki Electric Industry Co Ltd
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Filing: 1988-07-06
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Granted: 1989-03-07
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Expires: 2008-07-06
Abstract
Abstract In a method of fabricating a semiconductor device, a trench is formed on a semiconductor substrate on which a circuit element or electrode conductor is formed, and is filled with polysilicon, a planarizing material is applied with polyvinyl alcohol (PVA) aqueous solution onto the polysilicon to form a PVA film, and the entire surface of the semiconductor substrate is dry-etched with etching conditions that makes the ratio of the etching rate of the PVA film and the polysilicon film to be within the range of 1:1 to 1:2.
Inventors
- 👤 Motoki Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:49
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/056; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268; H10P50/28; H10P50/286; H10P50/287; H10W10/00; H10W10/01; H10W10/041; H10W10/40; H10W20/071; H10W20/092
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
87 words
A method of fabricating a semiconductor device comprising the steps of: (a) forming a trench on a semiconductor substrate; (b) filling the trench with polysilicon; (c) applying a planarizing material with polyvinyl alcohol aqueous solution onto said polysilicon to form a polyvinyl alcohol film; and (d) performing a dry etching over the entire surface of the semiconductor substrate with etching conditions that makes the ratio of the etching rate of said polyvinyl alcohol film and said polysilicon film to be within the range of 1:1 to 1:2.
Claim 2
Independent Claim
87 words
A method of fabricating a semiconductor device comprising the steps of: (a) forming a trench on a semiconductor substrate; (b) filling the trench with polysilicon; (c) applying a planarizing material with polyvinyl alcohol aqueous solution onto said polysilicon to form a polyvinyl alcohol film; and (d) performing a dry etching over the entire surface of the semiconductor substrate with etching conditions that makes the ratio of the etching rate of said polyvinyl alcohol film and said polysilicon film to be within the range of 1:1 to 1:2.
Claim 3
Dependent Claim
18 words
A method according to claim 1, wherein said substrate has a circuit element and electrode conductor formed therein.
Claim 4
Dependent Claim
11 words
A method according to claim 1, wherein said semiconductor is silicon.
Claim 5
Dependent Claim
23 words
A method according to claim 1, wherein said step of applying the polyvinyl alcohol aqueous solution comprises spin-coating the polyvinyl alcohol aqueous solution.
Claim 6
Dependent Claim
41 words
A method according to claim 4, wherein said step of spin-coating the polyvinyl alcohol aqueous solution comprises spin-coating at a lower speed until the entire surface is covered with the polyvinyl alcohol aqueous solution and then spin-coating at a higher speed.
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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) | 1992-03-06 | 1992-09-05 | 1993-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-06 | 1996-09-05 | 1997-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-06 | 2000-09-05 | 2001-03-07 | $7700.00 | Window Closed / Lapsed |