US4160691A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Etch process for chromium
Assignee: International Business Machines Corp
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Filing: 1977-12-09
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Granted: 1979-07-10
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Expires: 1997-12-09
Abstract
Abstract Chromium/copper/chromium conductor lines and glass-chromium cermet resistor structures are formed on a substrate by a subtractive etch process in which undercutting of the top chromium layer and changes in the resistivity of the cermet are minimized by etching the chromium with a mixture of a low concentration (about 5 to 20% by volume) of concentrated (37%) HCl in about 65 to 95% by volume of an aliphatic alcohol such as glycerine with the remainder, if any, to make 100% being water at an elevated temperature of from about 50 DEG to 95 DEG C.
Inventors
- 👤 Oscar R. Abolafia
- 👤 John Rasile
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:10
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/01; H10W70/05; C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/16; C23F1/26; H01; H01C; H01C17/00; H01C17/06
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
55 words
A process for etching chromium comprising contacting the chromium with a mixture comprising from about 5 to 20% by volume of concentrated HCl, from about 65 to 95% by volume of a water miscible organic solvent and from about 0 to 30% by volume water at a temperature of from about 50° to 95° C.
Claim 2
Dependent Claim
55 words
A process for etching chromium comprising contacting the chromium with a mixture comprising from about 5 to 20% by volume of concentrated HCl, from about 65 to 95% by volume of a water miscible organic solvent and from about 0 to 30% by volume water at a temperature of from about 50° to 95° C.
Claim 3
Dependent Claim
26 words
The process of claim 1 wherein the organic solvent is an aliphatic alcohol having a boiling point in the range of about 190° to 300° C.
Claim 4
Dependent Claim
35 words
The process of claim 1 wherein the mixture comprises about 75% by volume glycerine, about 12.5% by volume concentrated HCl and about 12.5% by volume deionized water and the etching temperature is about 70° C.
Claim 5
Dependent Claim
13 words
The process of claim 2 wherein the aliphatic alcohol is a polyhydric alcohol.
Claim 6
Dependent Claim
16 words
The process of claim 1 wherein the etching temperature ranges from about 65° to 75° C.
Claim 7
Dependent Claim
66 words
A process for selectively etching a chromium layer from a layer of chromium containing cermet comprising contacting the chromium layer with a mixture comprising from about 5 to 20% by volume of concentrated HCl, from about 65 to 95% by volume of a water miscible organic solvent and from about 0 to 30% by volume water at a temperature of from about 50° to 95° C.
Claim 8
Dependent Claim
66 words
A process for selectively etching a chromium layer from a layer of chromium containing cermet comprising contacting the chromium layer with a mixture comprising from about 5 to 20% by volume of concentrated HCl, from about 65 to 95% by volume of a water miscible organic solvent and from about 0 to 30% by volume water at a temperature of from about 50° to 95° C.
Claim 9
Dependent Claim
13 words
The process of claim 6 wherein the cermet contains silicon oxide and chromium.
Claim 10
Dependent Claim
140 words
In a process for forming a chromium/copper/chromium conductor line and a glass-chromium cermet resistor structure on an insulating substrate in which successive layers of cermet, chromium, copper and chromium are formed on an insulating substrate and portions of the layers are removed by selective etching through patterned resist masks, the improvement which comprises etching the bottom chromium layer by contacting said layer with a mixture comprising from about 5 to 20% by volume of concentrated hydrochloric acid, about 65 to 95% by volume of a water miscible aliphatic alcohol having a boiling point in the range of about 190° to 300° C. and from about 0 to 30% by volume of water at a temperature of from about 50° to 95° C. whereby the undercutting of the top chromium layer and changes in the resistivity of the cermet are minimized.
Claim 11
Dependent Claim
140 words
In a process for forming a chromium/copper/chromium conductor line and a glass-chromium cermet resistor structure on an insulating substrate in which successive layers of cermet, chromium, copper and chromium are formed on an insulating substrate and portions of the layers are removed by selective etching through patterned resist masks, the improvement which comprises etching the bottom chromium layer by contacting said layer with a mixture comprising from about 5 to 20% by volume of concentrated hydrochloric acid, about 65 to 95% by volume of a water miscible aliphatic alcohol having a boiling point in the range of about 190° to 300° C. and from about 0 to 30% by volume of water at a temperature of from about 50° to 95° C. whereby the undercutting of the top chromium layer and changes in the resistivity of the cermet are minimized.
Claim 12
Dependent Claim
16 words
The process of claim 8 wherein the etching temperature ranges from about 65° to 75° C.
Claim 13
Dependent Claim
34 words
The process of claim 8 wherein the etching solution comprises about 75% by volume glycerine, about 12.5% by volume concentrated HCl and about 12.5% by volume water and the etching temperature is 70° C.
References Cited (Backward Citations)
US2230156A
Cited
US2687345A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-07-09 | 1983-01-08 | 1983-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-07-09 | 1987-01-08 | 1987-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-07-09 | 1991-01-08 | 1991-07-10 | $7700.00 | Window Closed / Lapsed |