US5294570A
Expired / Lapsed
US
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Reduction of foreign particulate matter on semiconductor wafers
Assignee: International Business Machines Corp
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Filing: 1992-01-29
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Granted: 1994-03-15
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Expires: 2012-01-29
Abstract
Abstract A substantial reduction in the foreign particulate matter contamination on surfaces, such as the surfaces of semiconductor wafers, is achieved by treating the surfaces with a solution comprising a strong acid and a very small amount of a fluorine-containing compound. A preferred method employs a solution containing sulfuric acid, hydrogen peroxide and a very small amount of hydrofluoric acid, which is effective in reducing foreign particulate matter contamination, without significant etching, of the surface being treated.
Inventors
- 👤 Marshall J. Fleming, Jr.
- 👤 William A. Syverson
- 👤 Eric J. White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:15
CPC Classifications
H; H10; H10P; H10P70/00; H10P70/10; H10P70/15; Y; Y10; Y10S; Y10S438/00; Y10S438/906; Y10S438/974
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
75 words
A method of reducing foreign particulate matter concentration on a surface, which comprises contacting said surface with a solution comprising a strong acid and a very small amount of a fluorine-containing compound, which is effective in reducing foreign particulate matter contamination, without significant etching, of said surface, wherein said amount of said fluorine-containing compound is sufficient to establish a chemophobic surface, and said surface is etched at a rate of less than about 20 Å/min.
Claim 2
Independent Claim
75 words
A method of reducing foreign particulate matter concentration on a surface, which comprises contacting said surface with a solution comprising a strong acid and a very small amount of a fluorine-containing compound, which is effective in reducing foreign particulate matter contamination, without significant etching, of said surface, wherein said amount of said fluorine-containing compound is sufficient to establish a chemophobic surface, and said surface is etched at a rate of less than about 20 Å/min.
Claim 3
Dependent Claim
19 words
The method of claim 1, wherein said surface is etched at a rate of less than about 5 Å/min.
Claim 4
Dependent Claim
19 words
The method of claim 2, wherein said surface is etched at a rate of less than about 2 Å/min.
Claim 5
Dependent Claim
12 words
The method of claim 1, wherein said fluorine-containing compound is hydrofluoric acid.
Claim 6
Dependent Claim
23 words
The method of claim 1, wherein said strong acid is selected from the group consisting of sulfuric acid, nitric acid and trifluoroacetic acid.
Claim 7
Dependent Claim
12 words
The method of claim 5, wherein said strong acid is sulfuric acid.
Claim 8
Dependent Claim
13 words
The method of claim 1, wherein said solution further comprises an oxidizing agent.
Claim 9
Dependent Claim
12 words
The method of claim 7, wherein said oxidizing agent is hydrogen peroxide.
Claim 10
Dependent Claim
19 words
The method of claim 8, wherein said strong acid is sulfuric acid and said fluorine-containing compound is hydrofluoric acid.
Claim 11
Dependent Claim
23 words
The method of claim 9, wherein said solution contains hydrofluoric acid in an amount of up to about 2.5×10 -3 percent by weight.
Claim 12
Dependent Claim
23 words
The method of claim 10, wherein said solution contains hydrofluoric acid in an amount of up to about 2×10 -4 percent by weight.
Claim 13
Independent Claim
90 words
A method of reducing foreign particulate matter concentration on a surface of a semiconductor wafer, which comprises immersing said wafer in a solution comprising a strong acid selected from the group consisting of sulfuric acid, nitric acid and trifluoroacetic acid and a very small amount of hydrofluoric acid, which is effective in reducing foreign particulate matter contamination, without significant etching, of said surface, wherein said amount of hydrofluoric acid is sufficient to establish a chemophobic surface, and said surface is etched at a rate of less than about 5 Å/min.
Claim 14
Independent Claim
90 words
A method of reducing foreign particulate matter concentration on a surface of a semiconductor wafer, which comprises immersing said wafer in a solution comprising a strong acid selected from the group consisting of sulfuric acid, nitric acid and trifluoroacetic acid and a very small amount of hydrofluoric acid, which is effective in reducing foreign particulate matter contamination, without significant etching, of said surface, wherein said amount of hydrofluoric acid is sufficient to establish a chemophobic surface, and said surface is etched at a rate of less than about 5 Å/min.
Claim 15
Dependent Claim
19 words
The method of claim 12, wherein said strong acid is sulfuric acid, and said solution further comprises hydrogen peroxide.
Claim 16
Dependent Claim
45 words
The method of claim 13, wherein said wafer is immersed in said solution for a period of time ranging from about a few seconds to about 10 minutes, and wherein said solution is maintained at a temperature ranging from about 90° to about 115° C.
Claim 17
Dependent Claim
37 words
The method of claim 14, wherein said solution contains hydrofluoric acid in an amount of up to about 2×10 -4 percent by weight, and said surface is etched at a rate of less than about 2 Å/min.
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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) | 1997-03-14 | 1997-09-13 | 1998-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-03-14 | 2001-09-13 | 2002-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-03-14 | 2005-09-13 | 2006-03-15 | $7700.00 | Window Closed / Lapsed |