US3979240A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of etching indium tin oxide
Assignee: General Electric Co
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Filing: 1975-05-02
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Granted: 1976-09-07
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Expires: 1995-05-02
Abstract
Abstract A method of etching a desired pattern in a layer of indium tin oxide formed on a substrate of a semiconductor or an insulating material in which the desired pattern is formed of a hardened photoresist on the layer of indium tin oxide and thereafter the substrate and the indium tin oxide layer with the hardened resist thereon is immersed in a solution of concentrated hydrobromic acid for a time sufficient to etch away the indium tin oxide unmasked by the hardened photoresist.
Inventors
- 👤 Mario Ghezzo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:07
CPC Classifications
H; H10; H10F; H10F71/00; H10F71/138; H10D; H10D64/00; H10D64/01; H10D64/011; Y; Y02; Y02E; Y02E10/00; Y02E10/50
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
103 words
A method of etching a first pattern in a layer of indium tin oxide on a surface of a substrate comprising applying a coating of photoresist material over the exposed surface of said layer of indium tin oxide, forming in said coating a hardened pattern identical to said first pattern and exposing said layer of indium tin oxide unmasked by said hardened pattern, immersing said substrate with said hardened photoresist thereon in a solution of hydrobromic acid for a time sufficient to etch away indium tin oxide unmasked by said hardened photoresist, removing said hardened photoresist from said layer of indium tin oxide.
Claim 2
Independent Claim
103 words
A method of etching a first pattern in a layer of indium tin oxide on a surface of a substrate comprising applying a coating of photoresist material over the exposed surface of said layer of indium tin oxide, forming in said coating a hardened pattern identical to said first pattern and exposing said layer of indium tin oxide unmasked by said hardened pattern, immersing said substrate with said hardened photoresist thereon in a solution of hydrobromic acid for a time sufficient to etch away indium tin oxide unmasked by said hardened photoresist, removing said hardened photoresist from said layer of indium tin oxide.
Claim 3
Dependent Claim
15 words
The method of claim 1 in which said photoresist material is a positive photoresist material.
Claim 4
Dependent Claim
15 words
The method of claim 1 in which said photoresist material is a negative photoresist material.
Claim 5
Dependent Claim
16 words
The method of claim 1 in which said solution of hydrobromic acid is a concentrated solution.
Claim 6
Dependent Claim
20 words
The method of claim 4 in which said concentrated solution comprises aqueous solution of about 48% hydrogen bromide by weight.
Claim 7
Dependent Claim
32 words
The method of claim 1 in which said substrate with said hardened photoresist thereon is immersed in a solution of concentrated hydrobromic acid for less than 20 minutes at substantially room temperature.
Claim 8
Dependent Claim
20 words
The method of claim 1 in which said layer of indium tin oxide is less than 1 micron in thickness.
Claim 9
Dependent Claim
20 words
The method of claim 1 in which the major constituent by weight of said indium tin oxide is indium oxide.
Claim 10
Dependent Claim
23 words
The method of claim 8 in which said indium tin oxide comprises about ninety per cent by weight of said indium tin oxide.
Claim 11
Dependent Claim
32 words
The method of claim 1 in which said layer of indium tin oxide is annealed to densify and increase the conductivity thereon prior to the application of said coating of photoresist thereto.
Claim 12
Dependent Claim
20 words
The method of claim 1 in which said substrate comprises an elemental semiconductor from the class of silicon and germanium.
Claim 13
Dependent Claim
23 words
The method of claim 1 in which said substrate comprises a compound semiconductor material from the class of gallium arsenide and gallium phosphide.
Claim 14
Dependent Claim
31 words
The method of claim 1 in which said substrate comprises an insulating material from the class of silicon dioxide, silicon nitride, mixtures of silicon dioxide and silicon nitride and aluminum oxide.
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) | 1979-09-07 | 1980-03-08 | 1980-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-07 | 1984-03-08 | 1984-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-07 | 1988-03-08 | 1988-09-07 | $7700.00 | Window Closed / Lapsed |