US4472459A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Local oxidation of silicon substrate using LPCVD silicon nitride
Assignee: Intersil Corp
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Filing: 1983-10-24
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Granted: 1984-09-18
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Expires: 2003-10-24
Abstract
Abstract The formation of silicon dioxide isolated silicon islands on the surface of a substrate is improved by utilizing as an oxidation mask a patterned layer of silicon nitride which is deposited by LPCVD directly onto the surface of the silicon wafer. The subject method substantially reduces the incidence of stress related defects in the silicon surface and therefore eliminates the need for a layer of pad oxide which, if present, would cause "bird's beak" formation.
Inventors
- 👤 Albert W. Fisher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:27
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P14/6308; H10P14/6309; H10P14/61; H10P14/69; H10P14/692; H10P14/6921; H10P14/69215; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/10; H10W10/13; H10P14/6326; H10P14/6328; H10P14/6334; H10P14/66; H10P14/668; H10P14/6681; H10P14/6682; H10P14/694; H10P14/6943; H10P14/69433
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
61 words
A method of forming a layer of silicon dioxide on a predetermined portion of a single crystalline silicon substrate comprising: depositing a single mask layer of silicon nitride about 700 and 1300 angstroms thick directly on the substrate by low pressure chemical vapor deposition; removing a predetermined portion thereof thus exposing the substrate; and forming silicon dioxide on the exposed substrate.
Claim 2
Independent Claim
61 words
A method of forming a layer of silicon dioxide on a predetermined portion of a single crystalline silicon substrate comprising: depositing a single mask layer of silicon nitride about 700 and 1300 angstroms thick directly on the substrate by low pressure chemical vapor deposition; removing a predetermined portion thereof thus exposing the substrate; and forming silicon dioxide on the exposed substrate.
Claim 3
Dependent Claim
40 words
A method in accordance with claim 1, wherein said layer of silicon nitride is deposited from a mixture of dichlorosilane and ammonia at a temperature of from about 775° to about 825° C. and a pressure of about 0.7 torr.
Claim 4
Dependent Claim
19 words
A method in accordance with claim 1, wherein said layer of silicon nitride is about 1000 angstroms in thickness.
Claim 5
Dependent Claim
42 words
A method in accordance with claim 1, wherein the portion of the silicon nitride layer is removed by forming a patterned layer of a resist material thereover and etching the portion of the silicon nitride layer not covered by the resist layer.
Claim 6
Dependent Claim
23 words
A method in accordance with claim 1, wherein a predetermined portion of the exposed silicon substrate is removed prior to forming the oxide.
Claim 7
Dependent Claim
24 words
A method in accordance with claim 5, wherein the silicon substrate is etched utilizing the patterned layer of silicon nitride as an etch mask.
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) | 1987-09-18 | 1988-03-19 | 1988-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-18 | 1992-03-19 | 1992-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-18 | 1996-03-19 | 1996-09-18 | $7700.00 | Window Closed / Lapsed |