Patent US4649099A successfully refreshed from Google Patents.
US4649099A
Expired / Lapsed
US
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Negative-type resist sensitive to ionizing radiation
Assignee: Dai Nippon Printing Co Ltd
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Filing: 1985-07-22
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Granted: 1987-03-10
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Expires: 2005-07-22
Abstract
Abstract An acetalized polyvinyl alcohol having a molecular weight of 10,000 to 1,000,000 represented by the formula ##STR1## wherein: R 1 represents a residue of an aldehyde or a ketone the residue having no photosenitivity to ultraviolet rays; R 2 represents a hydrogen atom, which may partially be substituted with an acetyl group; R 3 represents naught or a monomeric unit copolymerizable with vinyl acetate; and l, m, n, are integers indicating polymerization degrees, has excellent characteristics such as high sensitivity, high resolving power and excellent dry etching resistance and is suitable as a negative-type resist in ionizing radiation lithography.
Inventors
- 👤 Kiyoshi Oguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:04
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/004; G03F7/038; Y; Y10; Y10S; Y10S430/00; Y10S430/143; Y10S430/146; Y10S430/167; Y10S438/00; Y10S438/942; Y10S438/948; Y10S438/949
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
131 words
An ionizing radiation lithography process, which comprises forming on a substrate a thin film of a resist comprising an acetalized polyvinyl alcohol polymer having a molecular weight of 10,000 to 1,000,000 represented by the formula: ##STR10## wherein: R 1 represents a residue of an aldehyde or a ketone, the residue having no photosensitivity to ultraviolet rays; R 2 represents a hydrogen atom, which may partially be substituted with an acetyl group; R 3 represents naught or a monomeric unit copolymerizable with vinyl acetate; and l, m, n are integers indicating polymerization degrees, subjecting the thin film of said resist to imagewise irradiation by ionizing radiation, dissolving away selectively the non-irradiated portions of the resist film to expose corresponding portions of the substrate, and etching selectively the exposed portions of the substrate.
Claim 2
Dependent Claim
131 words
An ionizing radiation lithography process, which comprises forming on a substrate a thin film of a resist comprising an acetalized polyvinyl alcohol polymer having a molecular weight of 10,000 to 1,000,000 represented by the formula: ##STR10## wherein: R 1 represents a residue of an aldehyde or a ketone, the residue having no photosensitivity to ultraviolet rays; R 2 represents a hydrogen atom, which may partially be substituted with an acetyl group; R 3 represents naught or a monomeric unit copolymerizable with vinyl acetate; and l, m, n are integers indicating polymerization degrees, subjecting the thin film of said resist to imagewise irradiation by ionizing radiation, dissolving away selectively the non-irradiated portions of the resist film to expose corresponding portions of the substrate, and etching selectively the exposed portions of the substrate.
Claim 3
Dependent Claim
36 words
An ionizing lithography process according to claim 1, wherein the non-irradiated portion is dissolved selectively with a solvent selected from the group consisting of aromatic hydrocarbons, chlorinated hydrocarbons, ethylene glycol ethers, lower alcohols and mixtures thereof.
Claim 4
Dependent Claim
47 words
An ionizing lithography process according to claim 1, wherein etching is carried out with the use of a gaseous etchant comprising a carbon halide gas selected from the group consisting of carbon tetrachloride gas, carbon tetrafluoride gas and a mixture of said carbon halide gas with oxygen.
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) | 1990-03-09 | 1990-09-08 | 1991-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-09 | 1994-09-08 | 1995-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-09 | 1998-09-08 | 1999-03-10 | $7700.00 | Window Closed / Lapsed |