US3860464A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oxide etchant
Assignee: AT&T Inc
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Filing: 1973-10-11
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Granted: 1975-01-14
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Expires: 1993-10-11
Abstract
Abstract A composition for selectively etching inorganic oxides with respect to titanium includes an oxidizing agent, a buffered aqueous solution of hydrofluoric acid, a tetrazolium salt and sufficient organic solvent to make a stable solution. During the etching process, tetrazolium cations are reduced to form an etch insoluble formazan dye which deposits upon negatively charged(cathodic)sites, thereby suppressing galvanic corrosion.
Inventors
- 👤 William Charles Erdman
- 👤 Victor Charles Garbarini
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:49
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; C; C23; C23F; C23F11/00; C23F11/04; H10P95/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
49 words
METAL INHIBITED OXIDE ETCHANT COMPRISING THE FOLLOWING COMPONENTS BY VOLUME BASED UPON THE TOTAL VOLUME OF ETCANT: A. 1-3 PERCENT HYDROGEN PEROXIDE, 30 PERCENT SOLUTION B. 0.2-0.05 PERCENT TETRAZOLIUM SALT, AND C. BUFFERED AQUEOUS HYDROFLUORIC ACID SOLUTION ENOUGH SOLVENT BEING PRESENT TO STABILIZE THE SOLUBILITY OF THE TETRAZOLUIM SALT.
Claim 2
Dependent Claim
49 words
METAL INHIBITED OXIDE ETCHANT COMPRISING THE FOLLOWING COMPONENTS BY VOLUME BASED UPON THE TOTAL VOLUME OF ETCANT: A. 1-3 PERCENT HYDROGEN PEROXIDE, 30 PERCENT SOLUTION B. 0.2-0.05 PERCENT TETRAZOLIUM SALT, AND C. BUFFERED AQUEOUS HYDROFLUORIC ACID SOLUTION ENOUGH SOLVENT BEING PRESENT TO STABILIZE THE SOLUBILITY OF THE TETRAZOLUIM SALT.
Claim 3
Dependent Claim
15 words
Etchant in accordance with claim 1 wherein said tetrazolium salt is of the general formula
Claim 4
Dependent Claim
15 words
Etchant in accordance with claim 2 wherein the hydrofluoric acid is buffered with ammonium fluoride.
Claim 5
Dependent Claim
11 words
Etchant in accordance with claim 2 wherein the solvent is methanol.
Claim 6
Dependent Claim
14 words
Etchant in accordance with claim 4 wherein the tetrazolium salt is triphenyl tetrazolium chloride.
Claim 7
Dependent Claim
54 words
In the fluoride etch treatment of a substrate having exposed areas of inorganic oxide soluble in said etch and a metal susceptible to attack by said etch, the improvement which comprises contacting said substrate with such fluoride etch which contains a tetrazolium salt as an inhibitor for attack of the etch on said metal.
Claim 8
Dependent Claim
54 words
In the fluoride etch treatment of a substrate having exposed areas of inorganic oxide soluble in said etch and a metal susceptible to attack by said etch, the improvement which comprises contacting said substrate with such fluoride etch which contains a tetrazolium salt as an inhibitor for attack of the etch on said metal.
Claim 9
Dependent Claim
55 words
Method in accordance with claim 6 wherein said etch comprises the following components by volume based upon the total volume of etchant. a. 1-3 percent hydrogen peroxide, 30 percent solution b. 0.02 to 0.05 percent tetrazolium salt c. buffered aqueous hydrofluoric acid solution, enough solvent being present to stabilize the solution of the tetrazolium salt.
Claim 10
Dependent Claim
15 words
Method in accordance with claim 6 wherein the tetrazolium salt is of the general formula
References Cited (Backward Citations)
US3421985A
Cited
US3560280A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-13 | 1978-07-15 | 1979-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-13 | 1982-07-15 | 1983-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-13 | 1986-07-15 | 1987-01-14 | $7700.00 | Window Closed / Lapsed |