Patent US3867218A successfully refreshed from Google Patents.
US3867218A
Expired / Lapsed
US
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Method of etching a pattern in a silicon nitride layer
Assignee: US Philips Corp
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Filing: 1973-04-25
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Granted: 1975-02-18
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Expires: 1993-04-25
Abstract
Abstract Etching of a pattern in a silicon nitride layer provided on a substrate, in which the etching bath consists of a dilute aqueous solution of hydrofluoric acid and phosphoric acid, in which ammonium fluoride is dissolved in a high concentration. Application in the manufacture of semiconductor devices.
Inventors
- 👤 Loic Henry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:33
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
73 words
A METHOD OF ETCHING A PATTERN IN A SILICON NITRIDE LAYER PROVIDED ON A SUBSTRATE, IN PARTICULAR FOR USE IN THE MANUFACTURE OF SEMICONDUCTOR DEVICES IN WHICH THE SUBSTRATE CONTAINS SEMICONDUCTOR MATERIAL, SAID METHOD COMPRISING APPLYING TO DESIRED PORTIONS OF THE SILICON NITRIDE LAYER AN ETHCHING BATH WHICH CONTAINS HYDROFLUORIC ACID, AMMONIUM FLUORIDE, PHOSPHORIC ACID, AND WATER IN QUANTITIES IN WHICH THE BATH FORMS A DILUTE ACID SOLUTION WITH HIGH AMMONIUM FLUORIDE CONTENT.
Claim 2
Independent Claim
73 words
A METHOD OF ETCHING A PATTERN IN A SILICON NITRIDE LAYER PROVIDED ON A SUBSTRATE, IN PARTICULAR FOR USE IN THE MANUFACTURE OF SEMICONDUCTOR DEVICES IN WHICH THE SUBSTRATE CONTAINS SEMICONDUCTOR MATERIAL, SAID METHOD COMPRISING APPLYING TO DESIRED PORTIONS OF THE SILICON NITRIDE LAYER AN ETHCHING BATH WHICH CONTAINS HYDROFLUORIC ACID, AMMONIUM FLUORIDE, PHOSPHORIC ACID, AND WATER IN QUANTITIES IN WHICH THE BATH FORMS A DILUTE ACID SOLUTION WITH HIGH AMMONIUM FLUORIDE CONTENT.
Claim 3
Dependent Claim
86 words
A method as claimed in claim 1, characterized in that the composition of the etching bath corresponds to a solution obtained by combining a quantity of concentrated hydrofluoric acid (50% by weight of HF) between 7 and 13 parts by volume, a quantity of water between 26 and 34 parts by volume, and a quantity of concentrated orthophosphoric acid (100% of H3PO4) between 1 and 10 parts by volume, and dissolving therein at least 60 gms of ammonium fluoride per 100 cm3 of the resulting mixture.
Claim 4
Dependent Claim
23 words
A method as claimed in claim 2, characterized in that the quantity of concentrated hydrofluoric acid is 9 to 11 parts by volume.
Claim 5
Dependent Claim
19 words
A method as claimed in claim 3, characterized in that the quantity of water is 28-32 parts by volume.
Claim 6
Dependent Claim
26 words
A method as claimed in claim 4, characterized in that at most 80 gms of crystalline ammonium fluoride is used per 100 cm3 of the mixture.
Claim 7
Dependent Claim
22 words
A method as claimed in claim 5, characterized in that the quantity of orthophosphoric acid is at most 8 parts by volume.
Claim 8
Dependent Claim
23 words
A method as claimed in claim 5, characterized in that the quantity of orthophosphoric acid is at least approximately 3 parts by volume.
Claim 9
Dependent Claim
22 words
A method as claimed in claim 7, characterized in that the quantity of orthophosphoric acid is at least 4 parts by volume.
Claim 10
Dependent Claim
41 words
A method as claimed in claim 2, characterized in that a masking pattern of a photoresist is formed directly on the silicon nitride layer and the etching treatment of the silicon nitride layer is carried out while using said masking pattern.
Claim 11
Dependent Claim
24 words
A method as claimed in claim 2, characterized in that the silicon nitride layer is provided on a substrate which contains a semiconductor material.
Claim 12
Dependent Claim
21 words
A method as claimed in claim 10, characterized in that the silicon nitride layer is provided directly on the semiconductor material.
Claim 13
Dependent Claim
16 words
A method as claimed in claim 9, characterized in that group III-V semiconductor material is used.
Claim 14
Dependent Claim
14 words
A method as claimed in claim 12, characterized in that gallium phosphide is used.
Claim 15
Dependent Claim
14 words
A method as claimed in claim 12, characterized in that gallium-aluminium arsenide is used.
References Cited (Backward Citations)
US3107188A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |