US4191603A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Making semiconductor structure with improved phosphosilicate glass isolation
Assignee: International Business Machines Corp
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Filing: 1978-05-01
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Granted: 1980-03-04
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Expires: 1998-05-01
Abstract
Abstract In a field effect device such as a charge coupled device or field effect transistor in which at least two levels of polycrystalline silicon conductors are used; these two levels of polycrystalline silicon are isolated from one another with a dielectric layer. Disclosed is a dielectric layer of reflowed phosphosilicate glass (PSG) on top surfaces of a polycrystalline silicon layer which may be doped by phosphorous impurities diffusing from the PSG.
Inventors
- 👤 Paul L. Garbarino
- 👤 Martin Revitz
- 👤 Joseph F. Shepard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:24
CPC Classifications
H; H10; H10P; H10P95/00; H10D; H10D84/00; H10D84/01; H10D84/0198; H10D84/02; H10D84/03; H10D84/038; Y; Y10; Y10S; Y10S148/00; Y10S148/053; Y10S148/133; Y10S438/00; Y10S438/942
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
94 words
A process for defining areas of polysilicon material on a surface comprising: depositing a layer of polysilicon material on said surface; depositing a layer of phosphosilicate glass over said layer of polysilicon material; forming a pattern of openings in the phosphosilicate glass by photolithography and etching; using the pattern in the phosphosilicate glass to form a like pattern in the polycrystalline silicon material wherein there is undercutting under the phosphosilicate glass mask; and substantially eliminating the undercutting under the phosphosilicate glass by heat treating the structure to cause the contraction of the phosphosilicate glass.
Claim 2
Dependent Claim
94 words
A process for defining areas of polysilicon material on a surface comprising: depositing a layer of polysilicon material on said surface; depositing a layer of phosphosilicate glass over said layer of polysilicon material; forming a pattern of openings in the phosphosilicate glass by photolithography and etching; using the pattern in the phosphosilicate glass to form a like pattern in the polycrystalline silicon material wherein there is undercutting under the phosphosilicate glass mask; and substantially eliminating the undercutting under the phosphosilicate glass by heat treating the structure to cause the contraction of the phosphosilicate glass.
Claim 3
Dependent Claim
23 words
A process as described in claim 1 wherein said step of depositing the layer of phosphosilicate glass takes place at approximately 450° C.
Claim 4
Dependent Claim
40 words
A process as in claims 1 or 2 wherein said step of substantially eliminating the undercutting under the phosphosilicate glass by heat treating takes place at approximately 1,000° C. in a nitrogen atmosphere for a period of approximately 1 hour.
Claim 5
Dependent Claim
22 words
A process as in claim 1 further comprising the step of: converting a sidewall portion of said polysilicon material to silicon dioxide.
Claim 6
Dependent Claim
21 words
A process as in claim 4 further comprising the step of: covering said structure with a blanket layer of polysilicon material.
Claim 7
Dependent Claim
33 words
A process as in claim 1 wherein said step of substantially eliminating the undercutting under the phosphosilicate glass by heat treating causes dopant from said phosphosilicate glass to diffuse into said polysilicon material.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-03-04 | 1983-09-03 | 1984-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-04 | 1987-09-03 | 1988-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-04 | 1991-09-03 | 1992-03-04 | $7700.00 | Window Closed / Lapsed |