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US4871651A
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Cryogenic process for metal lift-off
Assignee: Ford Motor Co
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Filing: 1988-06-27
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Granted: 1989-10-03
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Expires: 2008-06-27
Abstract
Abstract This invention is directed to a process for the cryogenic lift-off of metal/resist material from a surface of a substrate.
Inventors
- 👤 Robert C. McCune, Jr.
- 👤 Louis Toth
- 👤 Robert S. Bailey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 01:34
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/26; G03F7/40; H; H10; H10P; H10P76/00; H10P76/20; H10P76/202; H05; H05K; H05K3/00; H05K3/10; H05K3/14; H05K3/143
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
160 words
A process for the cryogenic lift-off of metal/resist material from a surface of a substrate, which process comprises: providing a layer of resist material in a desired pattern on a surface of a substrate, said substrate possessing a thermal coefficient of expansion different from that of said resist material and said layer (i) defining uncovered surface areas of said substrate and (ii) having undercut side walls adjacent said uncovered surface areas; then applying a layer of metal whereby a first portion of said metal deposits on the surface of said resist material and a second portion of said metal deposits on said uncovered surface areas of said substrate forming a layered article, said metal being adherent to said surface of said substrate, said first portion and said portion thereof not being in contact with each other; and then subjecting said layered article to a temperature sufficiently low to cause said resist layer to detach from said surface of said substrate.
Claim 2
Dependent Claim
160 words
A process for the cryogenic lift-off of metal/resist material from a surface of a substrate, which process comprises: providing a layer of resist material in a desired pattern on a surface of a substrate, said substrate possessing a thermal coefficient of expansion different from that of said resist material and said layer (i) defining uncovered surface areas of said substrate and (ii) having undercut side walls adjacent said uncovered surface areas; then applying a layer of metal whereby a first portion of said metal deposits on the surface of said resist material and a second portion of said metal deposits on said uncovered surface areas of said substrate forming a layered article, said metal being adherent to said surface of said substrate, said first portion and said portion thereof not being in contact with each other; and then subjecting said layered article to a temperature sufficiently low to cause said resist layer to detach from said surface of said substrate.
Claim 3
Dependent Claim
20 words
The process according to claim 1, wherein said resist material is selected from positive photoresist materials and negative photoresist materials.
Claim 4
Dependent Claim
13 words
The process according to claim 1, wherein said substrate is a semiconductor material.
Claim 5
Dependent Claim
19 words
The process according to claim 3, wherein said semiconductor material is selected from silicon, gallium arsenide and indium phosphide.
Claim 6
Dependent Claim
16 words
The process according to claim 4, wherein said substrate is a wafer of single crystal silicon.
Claim 7
Dependent Claim
30 words
The process according to claim 1, wherein said metal is selected from aluminum, iron, nickel, copper, lead, silver, chromium, tungsten, tin, platinum, molybdenum, gold and alloys of any of them.
Claim 8
Dependent Claim
23 words
The process according to claim 1, wherein said layer of metal is applied by a technique selected from evaporation and sputtering deposition methods.
Claim 9
Dependent Claim
29 words
The process according to claim 1, wherein said layered article is subjected to a cryogenic temperature to cause said resist layer to detach from said surface of said substrate.
Claim 10
Dependent Claim
28 words
The process according to claim 8, wherein said layered article is subjected to liquid nitrogen to cause said resist layer to detach from said surface of said substrate.
References Cited (Backward Citations)
US4631250A
Cited
US4662989A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-02 | 1993-04-03 | 1993-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-02 | 1997-04-03 | 1997-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-02 | 2001-04-03 | 2001-10-03 | $7700.00 | Window Closed / Lapsed |