US5840629A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Copper chemical mechanical polishing slurry utilizing a chromate oxidant
Assignee: State University of New York Polytechnic Institute
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Filing: 1995-12-14
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Granted: 1998-11-24
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Expires: 2015-12-14
Abstract
Abstract There is described a slurry for use in chemical mechanical polishing of copper layers in integrated circuit fabrication. The slurry includes a chromate oxidant, such as sodium chromate tetrahydrate (Na 2 CrO 4 .4H 2 O). The chromate oxidant provides a slightly basic slurry solution that enhances removal characteristics for copper layers. In one embodiment, the slurry has a pH between about 6 and about 9.
Inventors
- 👤 Ronald A. Carpio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:18
CPC Classifications
C; C09; C09K; C09K3/00; C09K3/14; C09K3/1454; C09K3/1463; C09G; C09G1/00; C09G1/02; H; H10; H10P; H10P52/00; H10P52/40; H10P52/403; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/062
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
88 words
A copper polishing slurry for use in chemical mechanical polishing of a copper layer formed atop a semiconductor wafer, said copper polishing slurry comprising a chromate salt, wherein said slurry is for use in chemical mechanical polishing of a copper layer, wherein said slurry allows rapid formation of a passive oxide film on said copper layer which reduces or prevents dissolution or etching of said copper, and wherein said slurry allows said passive oxide film to be removed when said passive oxide film is subjected to abrasive action.
Claim 2
Dependent Claim
88 words
A copper polishing slurry for use in chemical mechanical polishing of a copper layer formed atop a semiconductor wafer, said copper polishing slurry comprising a chromate salt, wherein said slurry is for use in chemical mechanical polishing of a copper layer, wherein said slurry allows rapid formation of a passive oxide film on said copper layer which reduces or prevents dissolution or etching of said copper, and wherein said slurry allows said passive oxide film to be removed when said passive oxide film is subjected to abrasive action.
Claim 3
Dependent Claim
19 words
The slurry of claim 1, wherein said salt is sodium chromate tetrahydrate (Na 2 CrO 4 .4H 2 O).
Claim 4
Dependent Claim
23 words
The slurry of claim 2 wherein a concentration of said sodium chromate tetrahydrate is equal to or less than about 5% by weight.
Claim 5
Dependent Claim
17 words
The slurry of claim 3 wherein said concentration is between about 0.5% and about 5% by weight.
Claim 6
Dependent Claim
13 words
The slurry of claim 1 wherein said salt is an aqueous soluble chromate.
Claim 7
Dependent Claim
15 words
The slurry of claim 1 wherein said slurry has a minimum pH of about 6.
Claim 8
Dependent Claim
12 words
The slurry of claim 6, further comprising sulfuric acid or chromic acid.
Claim 9
Dependent Claim
18 words
The slurry of claim 6 wherein said slurry has a pH of between about 7 and about 8.5.
Claim 10
Dependent Claim
83 words
A slurry for use in chemical mechanical polishing of a metal layer formed on a semiconductor wafer, said slurry comprising a chromate oxidant wherein said slurry has a pH of between about 6 and about 9, wherein said slurry allows rapid formation of a passive oxide film on said metal layer which reduces or prevents dissolution or etching of said metal, and wherein said slurry allows said passive oxide film to be removed when said passive oxide film is subjected to abrasive action.
Claim 11
Dependent Claim
83 words
A slurry for use in chemical mechanical polishing of a metal layer formed on a semiconductor wafer, said slurry comprising a chromate oxidant wherein said slurry has a pH of between about 6 and about 9, wherein said slurry allows rapid formation of a passive oxide film on said metal layer which reduces or prevents dissolution or etching of said metal, and wherein said slurry allows said passive oxide film to be removed when said passive oxide film is subjected to abrasive action.
Claim 12
Dependent Claim
20 words
The slurry of claim 9 wherein said chromate oxidant is sodium chromate tetrahydrate (Na 2 CrO 4 .4H 2 O).
Claim 13
Dependent Claim
18 words
The slurry of claim 10, said slurry being for use in chemical mechanical polishing of a copper layer.
Claim 14
Dependent Claim
23 words
The slurry of claim 10 wherein a concentration of said sodium chromate tetrahydrate is equal to or less than about 5% by weight.
Claim 15
Dependent Claim
17 words
The slurry of claim 12 wherein said concentration is between about 0.5% and about 5% by weight.
Claim 16
Dependent Claim
12 words
The slurry of claim 10, further comprising sulfuric acid or chromic acid.
Claim 17
Dependent Claim
18 words
The slurry of claim 10 wherein said slurry has a pH of between about 7 and about 8.5.
Claim 18
Independent Claim
97 words
A method for forming a metal feature on a semiconductor wafer, said method comprising: forming a metal layer atop an upper surface of said wafer; and chemical mechanical polishing said metal layer using a slurry comprising a chromate oxidant and having a pH of between about 6 and about 9, wherein said slurry allows rapid formation of a passive oxide film on said metal layer which reduces or prevents dissolution or etching of said metal, and wherein said slurry allows said passive oxide film to be removed when said passive oxide film is subjected to abrasive action.
Claim 19
Independent Claim
97 words
A method for forming a metal feature on a semiconductor wafer, said method comprising: forming a metal layer atop an upper surface of said wafer; and chemical mechanical polishing said metal layer using a slurry comprising a chromate oxidant and having a pH of between about 6 and about 9, wherein said slurry allows rapid formation of a passive oxide film on said metal layer which reduces or prevents dissolution or etching of said metal, and wherein said slurry allows said passive oxide film to be removed when said passive oxide film is subjected to abrasive action.
Claim 20
Dependent Claim
20 words
The method of claim 16 wherein said chromate oxidant comprises sodium chromate tetrahydrate (Na 2 CrO 4 .4H 2 O).
Claim 21
Dependent Claim
22 words
The method of claim 17 wherein said sodium chromate tetrahydrate is present in a concentration of about 0.5 to 5.0% by weight.
Claim 22
Dependent Claim
11 words
The method of claim 16 wherein said metal layer comprises copper.
Claim 23
Dependent Claim
20 words
The method of claim 19 wherein said chromate oxidant comprises sodium chromate tetrahydrate (Na 2 CrO 4 .4H 2 O).
Claim 24
Dependent Claim
12 words
The slurry of claim 1, wherein said slurry further comprised abrasive particles.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-11-23 | 2002-05-25 | 2002-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-11-23 | 2006-05-25 | 2006-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-11-23 | 2010-05-25 | 2010-11-24 | $7700.00 | Window Closed / Lapsed |