Patent US4428796A successfully refreshed from Google Patents.
US4428796A
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Adhesion bond-breaking of lift-off regions on semiconductor structures
Assignee: National Semiconductor Corp
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Filing: 1982-08-02
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Granted: 1984-01-31
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Expires: 2002-08-02
Abstract
Abstract A process is described for removing polyimide regions adhered to the surface of a semiconductor structure 10 which includes the steps of heating the structure 10 and the polyimide regions 12 to between 450° and 490° C., immersing the structure in a solution of one of methylene chloride and ethylene diamine/hydrazine, and ultrasonerating the solution and the semiconductor structure.
Inventors
- 👤 Alvin Milgram
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:54
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/056; H10W20/058; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/286; H10P50/287; H10P76/00; H10P76/20; H10P76/202; H05; H05K; H05K3/00; H05K3/02; H05K3/04; H05K3/046; H05K3/048; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/948; Y10S438/951
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
46 words
A process for removing polyimide regions adhered to semiconductor structures comprising: heating the structure and the polyimide regions to between 450° and 490° C.; immersing the structure in a solution of one of methylene chloride and ethylene diamene/hydrazine; and ultrasonerating the solution and the semiconductor structure.
Claim 2
Dependent Claim
46 words
A process for removing polyimide regions adhered to semiconductor structures comprising: heating the structure and the polyimide regions to between 450° and 490° C.; immersing the structure in a solution of one of methylene chloride and ethylene diamene/hydrazine; and ultrasonerating the solution and the semiconductor structure.
Claim 3
Dependent Claim
16 words
A process as in claim 1 wherein the step of heating comprises heating in dry nitrogen.
Claim 4
Dependent Claim
18 words
A process as in claim 2 wherein the step of heating further comprises heating for about one hour.
Claim 5
Dependent Claim
24 words
A process as in claim 1 wherein the step of immersing the structure is preceded by a step of boiling the structure in water.
Claim 6
Dependent Claim
13 words
A process as in claim 4 wherein the water includes a wetting agent.
Claim 7
Dependent Claim
18 words
A process as in claim 1 wherein the ethylene diamene/hydrazine solution comprises about 40 percent hydrazine by volume.
Claim 8
Dependent Claim
18 words
A process as in claim 1 wherein the step of heating comprises heating in a gas comprising hydrogen.
References Cited (Backward Citations)
US3873361A
Cited
US4256816A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-30 | 1987-08-01 | 1988-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-30 | 1991-08-01 | 1992-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-30 | 1995-08-01 | 1996-01-31 | $7700.00 | Window Closed / Lapsed |