US3873313A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for forming a resist mask
Assignee: International Business Machines Corp
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Filing: 1973-05-21
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Granted: 1975-03-25
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Expires: 1993-05-21
Abstract
Abstract A resist mask formation process in which a first layer of photoresist is applied to a substrate, blanket exposed to react the photoactive material in the resist and postbaked. A second layer of photoresist is then applied, exposed patternwise, and portions of the substrate are uncovered by solvent development of the resist layers.
Inventors
- 👤 Richard S Horst
- 👤 Leon H Kaplan
- 👤 David P Merritt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:27
CPC Classifications
H; H10; H10P; H10P95/00; G; G03; G03F; G03F7/00; G03F7/004; G03F7/09; G03F7/11; H10W; H10W74/00; H10W74/40; H10W74/47
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
113 words
A PROCESS FOR FORMING A RESIST MASK ON A SUBSTRATE COMPRISING THE STEPS OF: FORMING A FIRST LAYER OF POSITIVE ACTING PHOTORESIST ON A SUBSTRATE, WHICH PHOTORESIST BECOMES MORE SOLUBLE UPON EXPOSURE TO ACTINIC RADIATION, BLANKET EXPOSING THE FIRST PHTORESIST LAYER WITH ACTINIC RADIATION SO AS TO REACT SUBSTANTIALLY ALL OF THE PHOTOSENSITIVE MATERIAL IN SAID PHOTORESIST WHICH WOULD CAUSE HEAT INDUCED CROSS-LINKING, BAKING SAID FIRST PHOTORESIST LAYER TO IMPROVE THE ADHESION OF SAID LAYER TO SAID SUBSTRATE WHILE AVOIDING HEAT INDUCED CROSS-LINKING OF SAID LAYER, FORMING A SECOND LAYER OF PHOTORESIST ON TOP OF THE FIRST LAYER, IMAGEWISE EXPOSING THE SECOND PHOTORESIST LAYER, AND DEVELOPING A RELIEF IMAGE IN THE PHOTORESIST LAYERS
Claim 2
Dependent Claim
113 words
A PROCESS FOR FORMING A RESIST MASK ON A SUBSTRATE COMPRISING THE STEPS OF: FORMING A FIRST LAYER OF POSITIVE ACTING PHOTORESIST ON A SUBSTRATE, WHICH PHOTORESIST BECOMES MORE SOLUBLE UPON EXPOSURE TO ACTINIC RADIATION, BLANKET EXPOSING THE FIRST PHTORESIST LAYER WITH ACTINIC RADIATION SO AS TO REACT SUBSTANTIALLY ALL OF THE PHOTOSENSITIVE MATERIAL IN SAID PHOTORESIST WHICH WOULD CAUSE HEAT INDUCED CROSS-LINKING, BAKING SAID FIRST PHOTORESIST LAYER TO IMPROVE THE ADHESION OF SAID LAYER TO SAID SUBSTRATE WHILE AVOIDING HEAT INDUCED CROSS-LINKING OF SAID LAYER, FORMING A SECOND LAYER OF PHOTORESIST ON TOP OF THE FIRST LAYER, IMAGEWISE EXPOSING THE SECOND PHOTORESIST LAYER, AND DEVELOPING A RELIEF IMAGE IN THE PHOTORESIST LAYERS
Claim 3
Dependent Claim
24 words
The process according to claim 1 wherein the first photoresist layer comprises a photoresist containing m-cresol formaldehyde novolak resin and a diazo ketone sensitizer.
Claim 4
Dependent Claim
14 words
The process of claim 1 wherein the second layer is a positive acting photoresist.
Claim 5
Dependent Claim
14 words
The process of claim 1 wherein the second layer is a negative acting photoresist.
Claim 6
Dependent Claim
24 words
The process of claim 2 wherein the photoresist layers are removed from the substrate following processing by treatment with a solvent at room temperature.
Claim 7
Dependent Claim
10 words
The process of claim 5 wherein said solvent is acetone.
Claim 8
Dependent Claim
20 words
The process of claim 1 wherein the baking step is carried out at a temperature of at least about 140*C.
Claim 9
Dependent Claim
60 words
The process according to claim 1, wherein said first and second layers of photoresist contain a m-cresol formaldehyde novolac resin and a diazo-ketone sensitizer said baking is at a temperature from about 140*C to about 170*C, and said relief image is developed by removing said layers in the areas where said second layer was exposed with an aqueous alkaline developer.
Claim 10
Dependent Claim
48 words
The process according to claim 4 wherein the developing of said relief image is by removal of the second layer in the unexposed areas with a solvent for the unexposed negative acting photoresist and then removing the underlying first layer with a solvent for the exposed positive resist.
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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |