US4415653A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making sensitive positive electron beam resists
Assignee: Honeywell Inc
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Filing: 1982-12-07
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Granted: 1983-11-15
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Expires: 2002-12-07
Abstract
Abstract The method of making highly sensitive positive electron beam resists comprised of copolymers of methacrylic acid (MAA) and methacrylonitrile (MCN) is disclosed utilizing a prebaking step in which the copolymer resist in film form on the substrate is prebaked at a temperature below the decomposition temperature to improve the sensitivity of the resist. The positive electron resists produced in accordance with the present invention exhibit a high sensitivity, and high plasma etch resistance which makes them desirable for dry etching techniques in addition to other masking techniques which enable submicron resolution.
Inventors
- 👤 Juey H. Lai
- 👤 Richard Douglas
- 👤 Lloyd Shepherd
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:27
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/004; G03F7/039; G03F7/16; G03F7/168; Y; Y10; Y10S; Y10S430/00; Y10S430/1053; Y10S430/1055; Y10S430/106; Y10S430/111
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
86 words
A method of producing a sensitive positive resist image comprising the steps of coating a substrate with a solution of a radiation sensitive copolymer comprising methacrylic acid and methacrylonitrile to form a thin polymeric film of said copolymer thereon; prebaking the coated substrate at a temperature below the decomposition temperature of said copolymer; exposing said polymeric film to ionizing radiation in a predetermined pattern to increase the solubility of the exposed areas thereof; and developing said polymeric film to remove said copolymer from said exposed areas.
Claim 2
Independent Claim
86 words
A method of producing a sensitive positive resist image comprising the steps of coating a substrate with a solution of a radiation sensitive copolymer comprising methacrylic acid and methacrylonitrile to form a thin polymeric film of said copolymer thereon; prebaking the coated substrate at a temperature below the decomposition temperature of said copolymer; exposing said polymeric film to ionizing radiation in a predetermined pattern to increase the solubility of the exposed areas thereof; and developing said polymeric film to remove said copolymer from said exposed areas.
Claim 3
Dependent Claim
21 words
The method according to claim 1 wherein said prebaking temperature is between 160° C. and the decomposition temperature of said polymer.
Claim 4
Dependent Claim
22 words
The method according to claim 1 wherein the weight average molecular weight of said copolymer is equal to or greater than 400,000.
Claim 5
Dependent Claim
32 words
The method according to claim 1 wherein said copolymer comprises from about 50 to 95 mole percent of methacrylic acid and from about 50 mole percent to about 5 mole percent methacrylonitrile.
Claim 6
Dependent Claim
13 words
The method according to claim 1 wherein said prebaking temperature is 200° C.
Claim 7
Dependent Claim
25 words
The method according to claim 2 wherein said prebaking step is carried out at said prebaking temperature from about 10 minutes to about 60 minutes.
Claim 8
Dependent Claim
24 words
The method according to claim 1 wherein said exposed copolymer film is developed by washing said exposed film and said substrate with methyl cellosolve.
Claim 9
Dependent Claim
14 words
The method according to claim 1 wherein said ionizing radiation is electron beam radiation.
Claim 10
Dependent Claim
25 words
The method according to claim 1 wherein said copolymer is prepared by solution polymerization using a free-radical initiator and obtained by precipitation from said solution.
Claim 11
Dependent Claim
25 words
The method according to claim 3 wherein said copolymer is prepared by solution polymerization using a free-radical initiator and obtained by precipitation from said solution.
Claim 12
Dependent Claim
24 words
The method according to claim 4 wherein said copolymer is prepared by solution polymerization using a free-radical initiator obtained by precipitation from said solution.
Claim 13
Dependent Claim
24 words
The method according to claim 1 wherein said coating is formed by spin coating and the solvent for the coating solution is methyl cellosolve.
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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) | 1986-11-14 | 1987-05-16 | 1987-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-11-14 | 1991-05-16 | 1991-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-11-14 | 1995-05-16 | 1995-11-15 | $7700.00 | Window Closed / Lapsed |