US3880684A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing semiconductor
Assignee: Mitsubishi Electric Corp
•
Filing: 1973-08-03
•
Granted: 1975-04-29
•
Expires: 1993-08-03
Abstract
Abstract A semiconductor is prepared by continuously etching at least two types of silicon compound membranes such as silicon dioxide (SiO2), silicon nitride (Si3N4) or a polycrystalline silicon membrane which are formed on a silicon substrate. A freon gas plasma is used for etching so that the two types of silicon compound membranes are continuously etched in a sloped form without any undercutting, as occurs in conventional chemical solution etching.
Inventors
- 👤 Haruhiko Abe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:49
CPC Classifications
H; H10; H10W; H10W74/00; H10W74/40; H10W74/43; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/262; H10P50/263; H10P50/264; H10P50/266; H10P50/267; H10P50/268; H10P50/28; H10P50/282; H10P50/283; H10P50/73; H10P76/00; H10P76/40; H10P76/405; H10P76/408; H10P76/4083; H10W74/47
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
118 words
A PROCESS FOR PREPARING A SEMICONDUCTOR COMPRISING A BASE LAYER, A FIRST SILICON COMPOUND MEMBRANE HAVING A FIRST ETCHING COEFFICIENT FORMED ON THE BASE LAYER AND A SECOND SILICON COMPOUND MEMBRANE HAVING A SECOND ETCHING COEFFICIENT LOWER THAN THE FIRST ETCHING COEFFICIENT FORMED ON THE FIRST SILICON COMPOUND MEMBRANE COMPRISE THE STEPS OF SLOPE ETCHING TO A FIRST EXTENT THE FIRST SILICON COMPOUND MEMBRANE HAVING A FIRST ETCHING COEFFICIENT USING A FLUOROHYDROCARBON OR FLUOROCHLORO HYDROCARBON GAS PLASMA AND SLOPE ETCHING TO A SECOND EXTENT GREATER THAN THE FIRST EXTENT THE SECOND SILICON COMPOUND MEMBRANE HAVE A SECOND ETCHING COEFFICIENT LOWER THAN THE FIRST ETCHING COEFFICIENT USING THE SAME FLUOROHYDROCARBON OR FLUOROCHLORO HYDROCARBON GAS PLASMA WHERBY UNDERCUTTING IS PREVENTED.
Claim 2
Dependent Claim
118 words
A PROCESS FOR PREPARING A SEMICONDUCTOR COMPRISING A BASE LAYER, A FIRST SILICON COMPOUND MEMBRANE HAVING A FIRST ETCHING COEFFICIENT FORMED ON THE BASE LAYER AND A SECOND SILICON COMPOUND MEMBRANE HAVING A SECOND ETCHING COEFFICIENT LOWER THAN THE FIRST ETCHING COEFFICIENT FORMED ON THE FIRST SILICON COMPOUND MEMBRANE COMPRISE THE STEPS OF SLOPE ETCHING TO A FIRST EXTENT THE FIRST SILICON COMPOUND MEMBRANE HAVING A FIRST ETCHING COEFFICIENT USING A FLUOROHYDROCARBON OR FLUOROCHLORO HYDROCARBON GAS PLASMA AND SLOPE ETCHING TO A SECOND EXTENT GREATER THAN THE FIRST EXTENT THE SECOND SILICON COMPOUND MEMBRANE HAVE A SECOND ETCHING COEFFICIENT LOWER THAN THE FIRST ETCHING COEFFICIENT USING THE SAME FLUOROHYDROCARBON OR FLUOROCHLORO HYDROCARBON GAS PLASMA WHERBY UNDERCUTTING IS PREVENTED.
Claim 3
Dependent Claim
25 words
A process for preparing a semiconductor in accordance with claim 1 wherein the first silicon compound is SiO2 and the second silicon compound is Si3N4.
Claim 4
Dependent Claim
49 words
A process for preparing a semiconductor in accordance with claim 1 wherein a polysilicon membrane is formed on the second silicon compound membrane and wherein the polysilicon membrane is slope etched to a third extent greater than the second extent by the same fluorohydrocarbon or fluorochloro hydrocarbon gas plasma.
Claim 5
Dependent Claim
30 words
A process for preparing a semiconductor in accordance with claim 1 wherein a corrosion resist membrane disposed on the semiconductor is removed by oxygen gas plasma formed in the chamber.
Claim 6
Dependent Claim
49 words
A process for preparing a semiconductor in accordance with claim 1 wherein fluorohydrocarbon or fluorochloro hydrocarbon gas plasma is formed by supplyig a mixture of fluorohydrocarbon or fluorochloro hydrocarbon and an inert gas to an evacuated chamber and applying high frequency power to an electrode wound about the chamber.
Claim 7
Dependent Claim
36 words
A process for preparing a semiconductor in accordance with claim 5 wherein the mixture of fluorohydrocarbon or fluorochloro hydrocarbon and inert gas is supplied to the chamber at the rate of 10-500 cubic centimeters per minute.
Claim 8
Dependent Claim
35 words
A process for preparing a semiconductor in accordance with claim 1 wherein the fluorohydrocarbon or fluorochloro hydrocarbon gas plasma is formed by mixing an inert gas with fluorohydrocarbon or fluorochloro hydrocarbon gas prior to etching.
Claim 9
Dependent Claim
31 words
A process for preparing a semiconductor in accordance with claim 7 wherein the speed of etching is controlled by varying the ratio of inert gas to fluorohydrocarbon or fluorochloro hydrocarbon gas.
Claim 10
Dependent Claim
24 words
A process for preparing a semiconductor in accordance with claim 7 wherein the etching is performed at a pressure of 0.3 to 0.8 Torr.
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) | 1978-04-28 | 1978-10-28 | 1979-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-28 | 1982-10-28 | 1983-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-28 | 1986-10-28 | 1987-04-29 | $7700.00 | Window Closed / Lapsed |