US4307176A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming a pattern
Assignee: Hitachi Ltd
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Filing: 1979-11-14
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Granted: 1981-12-22
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Expires: 1999-11-14
Abstract
Abstract A method of forming a pattern comprising heat-treating a resist film subjected to irradiation with light and thereafter removing an unhardened area of the resist film. Since the heat treatment reduces the film thickness of the unhardened area and hardens a hardened area still more, a pattern on the order of submicrons can be readily formed.
Inventors
- 👤 Kozo Mochiji
- 👤 Shinji Okazaki
- 👤 Shojiro Asai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:00
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/004; G03F7/039; G03F7/26; G03F7/38
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
115 words
A method of accurately forming a microscopic pattern, comprising: (a) the step of depositing a positive electron beam resist film on an object surface on which the pattern is to be formed, (b) the step of irradiating a desired area of said resist film with an electron beam to increase the solubility of the irradiated area, thereby forming an unhardened irradiated area in said resist film, (c) the step of heat-treating said electron beam resist film to approximately 100°-200° C. at a reduced pressure of about 1 to 5 torr to decrease the thickness of the irradiated area by volatization, and (d) the step of removing the unhardened area of said electron beam resist film.
Claim 2
Independent Claim
115 words
A method of accurately forming a microscopic pattern, comprising: (a) the step of depositing a positive electron beam resist film on an object surface on which the pattern is to be formed, (b) the step of irradiating a desired area of said resist film with an electron beam to increase the solubility of the irradiated area, thereby forming an unhardened irradiated area in said resist film, (c) the step of heat-treating said electron beam resist film to approximately 100°-200° C. at a reduced pressure of about 1 to 5 torr to decrease the thickness of the irradiated area by volatization, and (d) the step of removing the unhardened area of said electron beam resist film.
Claim 3
Dependent Claim
20 words
A method of forming a pattern as defined in claim 1, wherein pre-baking is performed prior to the step (b).
Claim 4
Dependent Claim
22 words
A method of forming a pattern as defined in claim 1 or 2, wherein the step (d) is performed by dry etching.
Claim 5
Dependent Claim
24 words
A method of forming a pattern as defined in claim 1 or 2, wherein the step (d) is performed by a wet type development.
Claim 6
Dependent Claim
26 words
A method of forming a pattern as defined in claim 1 or 2, wherein the heat treatment in the step (c) is performed for 30-60 minutes.
Claim 7
Dependent Claim
43 words
A method of forming a pattern as defined in claim 1, wherein the positive type resist is selected from the group consisting of a copolymer of methyl methacrylate and acrylonitrile, polymethyl methacrylate, hexafluorobutyl methacrylate, and a copolymer of methyl methacrylate and methacrylic acid.
Claim 8
Dependent Claim
21 words
A method of forming a pattern as defined in claim 3, wherein the dry etching is either plasma etching or sputtering.
Claim 9
Dependent Claim
18 words
A method of forming a pattern as defined in claim 7, wherein the dry etching is plasma etching.
Claim 10
Dependent Claim
31 words
A method of forming a pattern as defined in claim 4, wherein a compound selected from the group consisting of N-amyl acetate and isoamyl acetate is used in the wet-type development.
Claim 11
Dependent Claim
23 words
A method of forming a pattern as defined in claim 1, wherein the heat-treating of step (c) is performed at approximately 150°-200° C.
Claim 12
Dependent Claim
19 words
A method of forming a pattern as defined in claim 2, wherein the pre-baking is at about 170° C.
Claim 13
Dependent Claim
29 words
A method of forming a pattern as defined in claim 5, wherein the electron beam has a charged density of about 8×10 -8 to 2×10 -5 coulomb/cm 2 .
References Cited (Backward Citations)
US4015986A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-12-21 | 1985-06-22 | 1985-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-21 | 1989-06-22 | 1989-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-21 | 1993-06-22 | 1993-12-22 | $7700.00 | Window Closed / Lapsed |