US4370197A
Expired / Lapsed
US
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Process for etching chrome
Assignee: International Business Machines Corp
•
Filing: 1981-06-24
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Granted: 1983-01-25
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Expires: 2001-06-24
Abstract
Abstract An aqueous acidic composition suitable for etching which contains an acid and a thiourea compound, and use thereof.
Inventors
- 👤 Oscar R. Abolafia
- 👤 Joseph G. Ameen
- 👤 Glenn V. Elmore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:10
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/16; C23F1/26
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
38 words
A method for etching chrome which comprises contacting the chrome with an acidic aqueous etchant composition containing water, an inorganic acid, and at least one thiourea compound selected from the group of thiourea, substituted thiourea, or mixtures thereof.
Claim 2
Independent Claim
38 words
A method for etching chrome which comprises contacting the chrome with an acidic aqueous etchant composition containing water, an inorganic acid, and at least one thiourea compound selected from the group of thiourea, substituted thiourea, or mixtures thereof.
Claim 3
Dependent Claim
26 words
The method of claim 1 wherein only preselected areas of chrome are etched and those areas not to be etched are protected by a photoresist material.
Claim 4
Dependent Claim
14 words
The method of claim 2 wherein such photoresist material is a positive photoresist material.
Claim 5
Dependent Claim
30 words
The method of claim 1 wherein the contacting is carried out for about 10 seconds to about 10 minutes, and the temperature employed is about 50° to about 90° C.
Claim 6
Dependent Claim
32 words
The method of claim 1 wherein the acid is present in the amount of about 1.5 to about 20% by weight and the pH of the composition is about 2 or less.
Claim 7
Dependent Claim
28 words
The method of claim 1 wherein the acid is present in an amount of about 8 to about 10% by weight based upon the weight of the composition.
Claim 8
Dependent Claim
17 words
The method of claim 1 wherein the pH of the etchant is about 0 to about 2.
Claim 9
Dependent Claim
18 words
The method of claim 1 wherein the pH is of the etchant is about 0 to about 1.
Claim 10
Dependent Claim
25 words
The method of claim 1 wherein said acid is selected from the group of hydrofluoric acid, hydrochloric acid, phosphoric acid, sulphuric acid or mixtures thereof.
Claim 11
Dependent Claim
11 words
The method of claim 1 wherein said acid includes sulphuric acid.
Claim 12
Dependent Claim
20 words
The method of claim 1 wherein the amount of said thiourea compound is about 1 to about 10% by weight.
Claim 13
Dependent Claim
20 words
The method of claim 1 wherein the amount of said thiourea compound is about 1 to about 3% by weight.
Claim 14
Dependent Claim
11 words
The method of claim 1 wherein said thiourea compound includes thiourea.
Claim 15
Dependent Claim
11 words
The method of claim 13 wherein said acid includes sulphuric acid.
Claim 16
Dependent Claim
15 words
The method of claim 1 wherein the temperature is about 60° to about 80° C.
Claim 17
Dependent Claim
23 words
The method of claim 1 wherein said substituted thiourea compound is selected from the group of alkylthiourea compounds, phenylthiourea compounds or mixtures thereof.
Claim 18
Dependent Claim
13 words
The method of claim 2 wherein beneath the chrome being etched is copper.
Claim 19
Dependent Claim
17 words
The method of claim 2 or 17 wherein chrome circuitry lines for integrated circuit chips are etched.
Claim 20
Dependent Claim
47 words
The method of claim 1 wherein said composition consists essentially of water, about 8 to about 10% by weight of sulfuric acid, and about 1 to about 10% by weight of at least one thiourea compound selected from the group of thiourea, substituted thiourea, or mixtures thereof.
Claim 21
Dependent Claim
11 words
The method of claim 19 wherein said thiourea compound is thiourea.
Claim 22
Dependent Claim
20 words
The method of claim 19 wherein the amount of said thiourea compound is about 1 to about 3% by weight.
Claim 23
Dependent Claim
73 words
The method of claim 1 wherein said composition consists essentially of about 1.5 to about 20% by weight of an acid selected from the group of hydrofluoric acid, hydrochloric acid, phosphoric acid, sulphuric acid, or mixtures thereof, about 1 to about 10% by weight of at least one thiourea compound selected from the group of thiourea, substituted thiourea, or mixtures thereof; and wherein the pH of the composition is about 2 or less.
Claim 24
Dependent Claim
11 words
The method of claim 22 wherein said thiourea compound is thiourea.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-01-24 | 1986-07-26 | 1987-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-24 | 1990-07-26 | 1991-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-24 | 1994-07-26 | 1995-01-25 | $7700.00 | Window Closed / Lapsed |