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US4425183A
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Metal bevel process for multi-level metal semiconductor applications
Assignee: MagnaChip Semiconductor Ltd
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Filing: 1983-08-08
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Granted: 1984-01-10
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Expires: 2003-08-08
Abstract
Abstract A process for beveling the sharp corners on an integrated circuit metal layer, which corners were created by commonly practiced masking and etching steps. In one form, the photoresist mask used to etch the lower level metal pattern is retained on the wafer as during the beveling operation. With a positive photoresist and an aluminum alloy metal lower level layer, an etch with an alkaline photoresist solvent will isotropically remove both photoresist and metal, but at a controlled difference in rate. Beveling of the metal corners suppresses the reentry effect otherwise encountered when subsequent dielectric materials are deposited over the lower level metal layer.
Inventors
- 👤 George Maheras
- 👤 Hubert O. Hayworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:37
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/02; H; H10; H10P; H10P50/00; H10P50/60; H10P50/66; H10P50/663; H10P50/667; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/061; H05K3/064; Y; Y10; Y10S; Y10S438/00; Y10S438/978
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
63 words
A process for beveling the corner formed at the interface between a patterned metallic material layer and an overlying mask material layer implemented during the processing of an integrated circuit wafer, comprising the step of: etching both the metallic material and masking material using an isotropic etchant which removes masking material at a rate measurably faster than the etchant removes the metallic material.
Claim 2
Dependent Claim
63 words
A process for beveling the corner formed at the interface between a patterned metallic material layer and an overlying mask material layer implemented during the processing of an integrated circuit wafer, comprising the step of: etching both the metallic material and masking material using an isotropic etchant which removes masking material at a rate measurably faster than the etchant removes the metallic material.
Claim 3
Dependent Claim
18 words
The process recited in claim 1, wherein the difference in etch rate is a nominal magnitude of 2.
Claim 4
Dependent Claim
22 words
The process recited in claim 2, wherein: the metallic material is an aluminum alloy; and the masking material is a polymer photoresist.
Claim 5
Dependent Claim
26 words
The process recited in claim 3, wherein: the masking material is a positive photoresist; and the etchant has a chemical pH number of 7 or greater.
Claim 6
Dependent Claim
25 words
The process recited in claim 3, including the prior step of: conditioning the polymer photoresist to cross-link the chemical composition for greater integrity during etching.
Claim 7
Dependent Claim
21 words
The process recited in claim 5, wherein the conditioning is comprised of a photoresist hardening in an inert gas plasma environment.
Claim 8
Dependent Claim
26 words
The process recited in claim 6, wherein: the masking material is a positive photoresist; and the etchant has a chemical pH number of 7 or greater.
Claim 9
Dependent Claim
37 words
The process recited in claim 4, wherein: the metallic material is an alloy of aluminum with small percentages by volume of copper and silicon; and the etchant has a chemical pH number in the range of 12.
References Cited (Backward Citations)
US4354897A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-09 | 1987-07-11 | 1988-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-09 | 1991-07-11 | 1992-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-09 | 1995-07-11 | 1996-01-10 | $7700.00 | Window Closed / Lapsed |