US3930870A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silicon polishing solution preparation
Assignee: International Business Machines Corp
•
Filing: 1973-12-28
•
Granted: 1976-01-06
•
Expires: 1993-12-28
Abstract
Abstract An improved process for preparing a polishing solution for use in the chemical-mechanical polishing of silicon comprising copper nitrate, ammonium fluoride, nitric acid and ammonium nitrate. The latter two components are added to the copper nitrate, the system mixed well and then the ammonium fluoride added. The process eliminates the need for settling, decantation or filtration during solution preparation and permits substantially lowered amounts of copper nitrate to be used for silicon polishing. The silicon polishing solution is also described.
Inventors
- 👤 Jagtar Singh Basi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:12
CPC Classifications
H; H10; H10P; H10P52/00; H10P52/40; H10P52/402
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
63 words
In a process for preparing a silicon chemical-mechanical polishing solution comprising cupric nitrate and ammonium fluoride in water in an amount effective to chemical-mechanical polish silicon, the improvement which comprises bringing cupric nitrate, ammonium nitrate and nitric acid into aqueous solution and then adding thereto ammonium fluoride, said nitric acid and ammonium nitrate being present in an amount effective to prevent copper precipitation.
Claim 2
Dependent Claim
63 words
In a process for preparing a silicon chemical-mechanical polishing solution comprising cupric nitrate and ammonium fluoride in water in an amount effective to chemical-mechanical polish silicon, the improvement which comprises bringing cupric nitrate, ammonium nitrate and nitric acid into aqueous solution and then adding thereto ammonium fluoride, said nitric acid and ammonium nitrate being present in an amount effective to prevent copper precipitation.
Claim 3
Dependent Claim
29 words
The process of claim 1 where the cupric nitrate is in the trihydrate form and the amount of cupric nitrate is greater than about 20 g/l of polishing solution.
Claim 4
Dependent Claim
20 words
The process of claim 2 where the amount of cupric nitrate is less than about 100 g/l of polishing solution.
Claim 5
Dependent Claim
32 words
The process of claim 2 where the ammonium fluoride is present in a concentration sufficient to provide a fluoride ion normality of about 2.1 to about 2.2 N in the polishing solution.
Claim 6
Dependent Claim
30 words
The process of claim 2 where the nitric acid is present in an amount of from about 6 to about 12 cc/l of polishing solution, calculated as 70% nitric acid.
Claim 7
Dependent Claim
22 words
The process of claim 5 where the ammonium nitrate is present in an amount greater than about 10 g/l of polishing solution.
Claim 8
Dependent Claim
60 words
The process of claim 2 where the polishing solution comprises: about 20 to about 100 g/l of cupric nitrate trihydrate; sufficient ammonium fluoride to provide a fluoride ion normality of about 2.1 to about 2.2 N; from about 6 to about 12 cc/l of nitric acid, calculated as 70% nitric acid; and greater than about 10 g/l of ammonium nitrate.
Claim 9
Dependent Claim
76 words
In a silicon chemical-mechanical polishing solution comprising cupric nitrate and ammonium fluoride in water in an amount effective to chemical-mechanical polish silicon, the improvement which comprises said silicon chemical-mechanical polishing solution further comprising nitric acid and ammonium nitrate in an amount effective to prevent the precipitation of copper from said cupric nitrate, said cupric nitrate being present in an amount which would cause copper precipitation but for the presence of said nitric acid and ammonium nitrate.
Claim 10
Dependent Claim
76 words
In a silicon chemical-mechanical polishing solution comprising cupric nitrate and ammonium fluoride in water in an amount effective to chemical-mechanical polish silicon, the improvement which comprises said silicon chemical-mechanical polishing solution further comprising nitric acid and ammonium nitrate in an amount effective to prevent the precipitation of copper from said cupric nitrate, said cupric nitrate being present in an amount which would cause copper precipitation but for the presence of said nitric acid and ammonium nitrate.
Claim 11
Dependent Claim
31 words
The chemical-mechanical polishing solution of claim 8 where the cupric nitrate is in the trihydrate form and the amount of cupric nitrate is greater than about 20 g/l of polishing solution.
Claim 12
Dependent Claim
22 words
The chemical-mechanical polishing solution of claim 9 where the amount of cupric nitrate is less than about 100 g/l of polishing solution.
Claim 13
Dependent Claim
34 words
The chemical-mechanical polishing solution of claim 9 where the ammonium fluoride is present in a concentration sufficient to provide a fluoride ion normality of about 2.1 to about 2.2 N in the polishing solution.
Claim 14
Dependent Claim
32 words
The chemical-mechanical polishing solution of claim 9 where the nitric acid is present in an amount of from about 6 to about 12 cc/l of polishing solution calculated as 70% nitric acid.
Claim 15
Dependent Claim
24 words
The chemical-mechanical polishing solution of claim 12 where the ammonium nitrate is present in an amount greater than about 10 g/l of polishing solution.
Claim 16
Dependent Claim
62 words
The chemical-mechanical polishing solution of claim 9 where the polishing solution comprises: about 20 to about 100 g/l of cupric nitrate trihydrate; sufficient ammonium fluoride to provide a fluoride ion normality of about 2.1 to about 2.2 N; from about 6 to about 12 cc/l of nitric acid, calculated as 70% nitric acid; and greater than about 10 g/l of ammonium nitrate.
Claim 17
Dependent Claim
19 words
The process of claim 7 where said ammonium nitrate is present in an amount up to about 20 g/l.
Claim 18
Dependent Claim
22 words
The chemical-mechanical polishing solution of claim 14 where the ammonium nitrate is present in an amount of up to about 20 g/l.
References Cited (Backward Citations)
US2410322A
Cited
US2588253A
Cited
GB693776A
Cited
US2814589A
Cited
US3088889A
Cited
US3155556A
Cited
US3436259A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-05 | 1979-07-07 | 1980-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-05 | 1983-07-07 | 1984-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-05 | 1987-07-07 | 1988-01-06 | $7700.00 | Window Closed / Lapsed |