US4050954A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface treatment of semiconductor substrates
Assignee: International Business Machines Corp
•
Filing: 1976-03-25
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Granted: 1977-09-27
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Expires: 1996-03-25
Abstract
Abstract The invention comprehends establishing a hydrophilic surface on polished semiconductor wafers, such as silicon, after polishing (e.g. silica polishing) by oxidation and hydrolysis of the wafer surface for conditioning thereof for post-polishing cleaning.
Inventors
- 👤 Jagtar S. Basi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:33
CPC Classifications
H; H10; H10P; H10P70/00; H10P70/10; H10P70/15
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
67 words
In a method of cleaning a silicon wafer polished with a metal oxide polishing medium, the improvement comprising: establishing hydrophilic surfaces on said wafer by oxidation thereof with an oxidizing agent selected from the group consisting of alkali metal hypohalites, and dichromates and permanganate salts of alkali metals in sulfuric acid, and including the step of treating the hydrophilic formed surfaces with an NH 4 OH solution.
Claim 2
Dependent Claim
67 words
In a method of cleaning a silicon wafer polished with a metal oxide polishing medium, the improvement comprising: establishing hydrophilic surfaces on said wafer by oxidation thereof with an oxidizing agent selected from the group consisting of alkali metal hypohalites, and dichromates and permanganate salts of alkali metals in sulfuric acid, and including the step of treating the hydrophilic formed surfaces with an NH 4 OH solution.
Claim 3
Dependent Claim
11 words
The method of claim 1 wherein said metal oxide is silica.
Claim 4
Dependent Claim
12 words
The method of claim 2 wherein said oxidizing agent is sodium hypochlorite.
Claim 5
Dependent Claim
23 words
The method of claim 1 including the step of converting said hydrophilic surfaces to a hydrophobic state by treatment with hydrofluoric acid solution.
Claim 6
Dependent Claim
23 words
The method of claim 4 including the further step of re-establishing a hydrophilic condition to said surfaces by retreatment with said oxidizing agents.
Claim 7
Dependent Claim
11 words
The method of claim 5 wherein said metal oxide is silica.
Claim 8
Dependent Claim
12 words
The method of claim 6 wherein said oxidizing agent is sodium hypochlorite.
Claim 9
Dependent Claim
107 words
In a method of cleaning silicon wafers polished with a metal oxide polishing medium, the improvement comprising: a. establishing hydrophilic surfaces on said wafers by oxidation with an oxidizing agent selected from the group consisting of alkali metal hypohalites, and dichromate and permanganate salts of alkali metals in sulfuric acid; b. treating said hydrophilic surfaces with an NH 4 OH solution to remove metal ions therefrom remaining from said polishing medium, c. establishing hydrophobic surfaces on said wafers by treatment with hydrofluoric acid solution and concurrently removing oxides therewith from said surfaces; and d. reconverting said surfaces to a hydrophilic condition with re-treatment with said oxidizing agent.
Claim 10
Dependent Claim
107 words
In a method of cleaning silicon wafers polished with a metal oxide polishing medium, the improvement comprising: a. establishing hydrophilic surfaces on said wafers by oxidation with an oxidizing agent selected from the group consisting of alkali metal hypohalites, and dichromate and permanganate salts of alkali metals in sulfuric acid; b. treating said hydrophilic surfaces with an NH 4 OH solution to remove metal ions therefrom remaining from said polishing medium, c. establishing hydrophobic surfaces on said wafers by treatment with hydrofluoric acid solution and concurrently removing oxides therewith from said surfaces; and d. reconverting said surfaces to a hydrophilic condition with re-treatment with said oxidizing agent.
Claim 11
Dependent Claim
12 words
The method of claim 8 wherein said metal oxide is silicon dioxide.
Claim 12
Dependent Claim
12 words
The method of claim 9 wherein said oxidizing agent is sodium hypohalite.
Claim 13
Dependent Claim
13 words
The method of claim 8 wherein said improvement is repeated at least once.
Claim 14
Dependent Claim
12 words
The method of claim 11 wherein said metal oxide is silicon dioxide.
Claim 15
Dependent Claim
12 words
The method of claim 12 wherein said oxidizing agent is sodium hypohalite.
References Cited (Backward Citations)
US2690383A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-26 | 1981-03-28 | 1981-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-26 | 1985-03-28 | 1985-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-26 | 1989-03-28 | 1989-09-27 | $7700.00 | Window Closed / Lapsed |