Patent US3900337A successfully refreshed from Google Patents.
US3900337A
Expired / Lapsed
US
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Method for stripping layers of organic material
Assignee: International Business Machines Corp
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Filing: 1974-04-05
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Granted: 1975-08-19
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Expires: 1994-04-05
Abstract
Abstract Layers of organic material, especially of polymerized photoresist, are removed by means of a mixture of an at least 95% H2SO4, and an at least 30% H2O2, at a ratio of at least 15:1 (referring to the anhydrous chemical substances). The H2O2 content of the aqueous H2O2 is to be in a ratio of at least 11:1 to the H2O content of the H2SO4. The cleaning effect is based on the dehydrating effect of the H2SO4, and the oxidizing effect of the H2O2.
Inventors
- 👤 Wolfgang Beck
- 👤 Friedrich C Brunner
- 👤 Peter U Frasch
- 👤 Blanka Ivancic
- 👤 Friedrich W Schwerdt
- 👤 Theodor Vogtmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:11
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/26; G03F7/42; G03F7/422; G03F7/423; H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/286; H10P50/287
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
69 words
METHOD FOR STRIPPING LAYERS OF ORGANIC MATERIAL FROM THE SURFACE WHICH IS RESISTANT TO OXIDIZING ACIDS COMPRISING: PROVIDING A MIXTURE OF H2SO4 AND H2O2 IN A RATIO OF AT LEAST ABOUT 15.1, ACID PEROXIDE, REFERRING TO VOLUME QUANTITIES OF THE ANHYDROUS CHEMICAL SUBSTANCES, USING AT LEAST 95% BY WEIGHT SULPHURIC ACID AND AN AT LEAST 30% H2O2 BY WEIGHT AQUEOUS H2O2 SOLUTION AND IMMERSING SAID SUBSTRATE IN SAID MIXTURE.
Claim 2
Dependent Claim
69 words
METHOD FOR STRIPPING LAYERS OF ORGANIC MATERIAL FROM THE SURFACE WHICH IS RESISTANT TO OXIDIZING ACIDS COMPRISING: PROVIDING A MIXTURE OF H2SO4 AND H2O2 IN A RATIO OF AT LEAST ABOUT 15.1, ACID PEROXIDE, REFERRING TO VOLUME QUANTITIES OF THE ANHYDROUS CHEMICAL SUBSTANCES, USING AT LEAST 95% BY WEIGHT SULPHURIC ACID AND AN AT LEAST 30% H2O2 BY WEIGHT AQUEOUS H2O2 SOLUTION AND IMMERSING SAID SUBSTRATE IN SAID MIXTURE.
Claim 3
Dependent Claim
29 words
The method of claim 1 including the steps of rinsing said substrate in water and drying said substrate after the resist has been stripped by immersion in said mixture.
Claim 4
Dependent Claim
39 words
The method of claim 1 in which the percent by weight H2O2 content of the aqueous H2O2 solution is in a weight percent ratio of at least 11:1 relative to the percent by weight water content of the H2SO4.
Claim 5
Dependent Claim
23 words
The method of claim 1 in which the volume quantities of H2SO4 and H2O2 are in a ratio between about 17:1 and 35:1.
Claim 6
Dependent Claim
23 words
The method of claim 3 in which the volume quantities of H2SO4 and H2O2 are in a ratio between about 17:1 and 35:1.
Claim 7
Dependent Claim
54 words
The method of claim 5 in which said substrate with the organic material is first immersed for a predetermined period of time in a mixture with an H2SO4 content approaching the upper limit of the mixture ratio, and subsequently for a predetermined period in a mixture with an H2SO4 content approaching the lower limit.
Claim 8
Dependent Claim
16 words
The method of claim 1 in which said organic material is removed from a semiconductor wafer.
Claim 9
Dependent Claim
14 words
The method of claim 1 in which said organic material is a patterned photoresist.
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) | 1978-08-18 | 1979-02-17 | 1979-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-18 | 1983-02-17 | 1983-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-18 | 1987-02-17 | 1987-08-19 | $7700.00 | Window Closed / Lapsed |