US3840982A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Contacts for semiconductor devices, particularly integrated circuits, and methods of making the same
Assignee: Westinghouse Electric Corp
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Filing: 1969-08-14
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Granted: 1974-10-15
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Expires: 1989-08-14
Abstract
Abstract The metal used for device contacts and for interconnections is separated from the bonding pad to which a lead wire is joined by highly doped semiconductive material that provides a conducting connection but avoids metallic contact therebetween. Aluminum may be used for contacts and interconnections while gold may be used for bonding pads and lead wires without being subject to purple plague. Methods of fabrication include particular sequences of selective deposition and/or selective removal of metal layers employing masks such as of photoresist material. The invention described herein was made in the performance of work under a NASA contract and is subject to the provisions of Sect. 305 of the National Aeronautics and Space Act of 1958, Public Law 85-568 (72 Stat. 435; 42 U.S.C. 2457).
Inventors
- 👤 M Schuster
- 👤 W Lytle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:05
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/20; H10P; H10P95/00; H10W20/40; H10W72/00; H10W72/50; H10W72/531; H10W72/536; H10W72/551; H10W72/552; H10W72/5522; H10W72/5524; H10W72/59; H10W72/90
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
288 words
A method of fabricating a semiconductor device comprising the steps of: A. forming a plurality of conductivity regions adjoining a planar surface of a semiconductor structure with a layer of insulating material extending on said surface; B. opening a first pattern of windows in said insulating layer to expose said semiconductor surface therein at a given conductivity region; C. depositing a layer of a first metal on said insulating layer and said exposed semiconductor surfAce at said first pattern of windows; D. selectively removing portions of said deposited metal layer to form a first metal pattern at least partially coincident with said first pattern of windows; E. heating the first metal pattern to bond said first metal directly to said conductivity region of said semiconductor structure; F. opening a second pattern of windows in said insulating layer by use of an apertured photoresist mask layer, said second windows being spaced from said first window pattern and said first metal pattern to expose said semiconductor surface at said given conductivity region; G. retaining said photoresist mask layer on said insulating layer and said first metal pattern wherein the openings therein at least partially coincide with said second pattern of windows to leave exposed said semiconductor surface exposed by said second pattern of windows; H. depositing at least a layer of a second metal uncompatible with said first metal over said photoresist mask layer and said exposed semiconductor surface at said second window pattern; I. removing said photoresist layer and said second metal thereover to form a second metal pattern at least partially coincident with said second pattern of windows; and J. heating said second metal pattern to bond said second metal to said conductivity region of said semiconductor structure.
Claim 2
Independent Claim
288 words
A method of fabricating a semiconductor device comprising the steps of: A. forming a plurality of conductivity regions adjoining a planar surface of a semiconductor structure with a layer of insulating material extending on said surface; B. opening a first pattern of windows in said insulating layer to expose said semiconductor surface therein at a given conductivity region; C. depositing a layer of a first metal on said insulating layer and said exposed semiconductor surfAce at said first pattern of windows; D. selectively removing portions of said deposited metal layer to form a first metal pattern at least partially coincident with said first pattern of windows; E. heating the first metal pattern to bond said first metal directly to said conductivity region of said semiconductor structure; F. opening a second pattern of windows in said insulating layer by use of an apertured photoresist mask layer, said second windows being spaced from said first window pattern and said first metal pattern to expose said semiconductor surface at said given conductivity region; G. retaining said photoresist mask layer on said insulating layer and said first metal pattern wherein the openings therein at least partially coincide with said second pattern of windows to leave exposed said semiconductor surface exposed by said second pattern of windows; H. depositing at least a layer of a second metal uncompatible with said first metal over said photoresist mask layer and said exposed semiconductor surface at said second window pattern; I. removing said photoresist layer and said second metal thereover to form a second metal pattern at least partially coincident with said second pattern of windows; and J. heating said second metal pattern to bond said second metal to said conductivity region of said semiconductor structure.
Claim 3
Dependent Claim
83 words
A method of fabricating a semiconductor device as set forth in claim 1 comprising the additional step of: prior to depositing said layer of said second metal, depositing an auxiliary metal layer to provide better adhesion of said second metal to said semiconductor structure on said photoresist mask layer and said exposed semiconductor surface at said second pattern of windows; and wherein: said second heating step bonds said auxiliary metal layer and said layer of said second metal thereover to said semiconductor structure.
Claim 4
Dependent Claim
55 words
A method of fabricating a semiconductor device as set forth in claim 1 wherein: said layer of said second metal is deposited directly on said photoresist mask layer and said exposed semiconductor surface at said second pattern of windows; and said second heating step bonds said layer of second metal directly to said semiconductor structure.
Claim 5
Independent Claim
290 words
A method of fabricating a semiconductor device comprising the steps of: A. forming a plurality of conductivity regions adjoining a planar surface of a semiconductor device with a layer of insulating material extending on said surface; B. opening a first pattern of windows in said insulating layer to expose said semiconductor surface therein at a given conductivity region; C. depositing a layer of a first metal consisting essentially of aluminum on said insulating layer and said exposed semiconductor surface at said first pattern of windows; D. selectively removing portions of said deposited aluminum layer to form a first metal pattern at least partially coincident with said first pattern of windows; E. heating said first metal pattern to bond said first metal directly to said conductivity region of said semiconductor structure; F. opening a second pattern of windows in said insulating layer by use of an apertured photoresist mask layer, said second windows being spaced from said first window pattern and said first metal pattern to expose said semiconductor surface at said given conductivity region; G. retaining said photoresist mask layer on said insulating layer and said first metal pattern wherein the openings therein at least partially coincide with said second pattern of windows to leave exposed said semiconductor surface exposed by said second pattern of windows; H. depositing at least a layer of a second metal comprising gold over said photoresist layer and said exposed semiconductor surface at said second window pattern; I. removing said photoresist mask layer and said second metal deposited thereover to form a second metal pattern aT least partially coincident with said second pattern of windows; and J. heating said second metal pattern to bond said second metal to said conductivity region of said semiconductor structure.
Claim 6
Independent Claim
290 words
A method of fabricating a semiconductor device comprising the steps of: A. forming a plurality of conductivity regions adjoining a planar surface of a semiconductor device with a layer of insulating material extending on said surface; B. opening a first pattern of windows in said insulating layer to expose said semiconductor surface therein at a given conductivity region; C. depositing a layer of a first metal consisting essentially of aluminum on said insulating layer and said exposed semiconductor surface at said first pattern of windows; D. selectively removing portions of said deposited aluminum layer to form a first metal pattern at least partially coincident with said first pattern of windows; E. heating said first metal pattern to bond said first metal directly to said conductivity region of said semiconductor structure; F. opening a second pattern of windows in said insulating layer by use of an apertured photoresist mask layer, said second windows being spaced from said first window pattern and said first metal pattern to expose said semiconductor surface at said given conductivity region; G. retaining said photoresist mask layer on said insulating layer and said first metal pattern wherein the openings therein at least partially coincide with said second pattern of windows to leave exposed said semiconductor surface exposed by said second pattern of windows; H. depositing at least a layer of a second metal comprising gold over said photoresist layer and said exposed semiconductor surface at said second window pattern; I. removing said photoresist mask layer and said second metal deposited thereover to form a second metal pattern aT least partially coincident with said second pattern of windows; and J. heating said second metal pattern to bond said second metal to said conductivity region of said semiconductor structure.
Claim 7
Dependent Claim
25 words
A method of fabricating a semiconductor device as set forth in claim 4 wherein: said layer of said second metal deposited consists essentially of gold.
Claim 8
Dependent Claim
72 words
A method of fabricating a semiconductor device as set forth in claim 4 comprising the additional step of: prior to depositing said layer of said second metal, depositing an auxiliary metal layer of chromium on said photoresist mask layer and said exposed semiconductor surface at said second pattern of windows; and wherein: said second heating step bonds said auxiliary metal layer and said layer of second metal thereover to the semiconductor structure.
Claim 9
Dependent Claim
55 words
A method of fabricating a semiconductor device as set forth in claim 4 wherein: said layer of said second metal is deposited directly on said photoresist mask layer and said exposed semiconductor surface at said second pattern of windows; and said second heating step bonds said layer of second metal directly to said semiconductor structure.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |