US4121936A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Positive resist for high energy radiation
Assignee: Fuji Chemical Industrial Co Ltd
•
Filing: 1977-06-13
•
Granted: 1978-10-24
•
Expires: 1997-06-13
Abstract
Abstract A film of poly(methacrylamide) is heated to partially form imide bonds with elimination of ammonia, and such imide bonding causes crosslinking in the polymer to form a crosslinked polymer film. This film can be advantageously adapted as a positive resist capable of forming a positive image by exposure to radiation such as electron beams. The minimum incident charge required for such exposure is of the order of 10-7 coulomb/cm2, which is far lower than the level required in the use of conventional resists. The resist provided according to this invention is also capable of forming an excellent heat-resistant positive resist image by short-time exposure to radiation.
Inventors
- 👤 Shunsuke Matsuda
- 👤 Soji Tsuchiya
- 👤 Masami Honma
- 👤 Gentaro Nagamatsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:54
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/004; G03F7/039
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
65 words
A resist material capable of forming a positive image by application of radiation, said material comprising a crosslinked polymer including the following structural units: ##STR4## and having a C/N atomic ratio within the range of more than 4 and up to 6, or a copolymer thereof with another vinyl monomer, said copolymer containing the vinyl monomer units in an amount of up to 10 mol%.
Claim 2
Dependent Claim
65 words
A resist material capable of forming a positive image by application of radiation, said material comprising a crosslinked polymer including the following structural units: ##STR4## and having a C/N atomic ratio within the range of more than 4 and up to 6, or a copolymer thereof with another vinyl monomer, said copolymer containing the vinyl monomer units in an amount of up to 10 mol%.
Claim 3
Dependent Claim
41 words
The resist material set forth in claim 1, said material being provided in the form of a film on a substrate to be etched which is made of a material selected from the group consisting of semi-conductors, metals and metal oxides.
Claim 4
Dependent Claim
41 words
The resist material set forth in claim 1, wherein the vinyl monomer is a member selected from the group consisting of acrolein, acrylonitrile, methacrylic acid, lower alkyl esters of acrylic acid, acrylamide, metal salts of acrylic acid, vinyl isothiocyanate and styrene.
Claim 5
Dependent Claim
26 words
The resist material set forth in claim 1, wherein the average molecular weight of the polymer or copolymer is within the range of 50,000 to 5,000,000.
Claim 6
Dependent Claim
21 words
The resist material set forth in claim 1, wherein the C/N atomic ratio is within the range of 4.09 to 6.0.
Claim 7
Independent Claim
100 words
A method of making a positive resist image comprising the steps of forming on a substrate to be etched a film of a resist material composed of a crosslinked polymer including the following structural units: ##STR5## and having a C/N atomic ratio within the range of more than 4 and up to 6, or a copolymer thereof with another vinyl monomer, said copolymer containing the vinyl monomer units in an amount of up to 10 mol%, exposing said film to radiation through a predetermined pattern to form a latent image, and then dissolving away the exposed portion with a solvent.
Claim 8
Independent Claim
100 words
A method of making a positive resist image comprising the steps of forming on a substrate to be etched a film of a resist material composed of a crosslinked polymer including the following structural units: ##STR5## and having a C/N atomic ratio within the range of more than 4 and up to 6, or a copolymer thereof with another vinyl monomer, said copolymer containing the vinyl monomer units in an amount of up to 10 mol%, exposing said film to radiation through a predetermined pattern to form a latent image, and then dissolving away the exposed portion with a solvent.
Claim 9
Dependent Claim
19 words
The method according to claim 6, wherein the substrate to be etched is made of semiconductor or a metal.
Claim 10
Dependent Claim
46 words
The method according to claim 6, wherein the other vinyl monomer is a member selected from the group consisting of acrolein, acrylonitrile, methacrylic acid, lower alkyl esters of acrylic acid, lower alkyl esters of methacrylic acid, acrylamide, metal salts of acrylic acid and vinyl isothiocyanate esters.
Claim 11
Dependent Claim
13 words
The method according to claim 6, wherein the radiation used is electron beams.
Claim 12
Dependent Claim
28 words
The method according to claim 6, wherein the solvent used for development is water or an aqueous alkaline solution with a pH of about 8 to about 12.
Claim 13
Dependent Claim
30 words
The method according to claim 6, wherein the formed positive resist image is washed with a solvent selected from the group consisting of methyl alcohol, ethyl alcohol and propyl alcohol.
Claim 14
Dependent Claim
20 words
The method according to claim 6, wherein the formed positive resist image is further subjected to an imide conversion reaction.
Claim 15
Dependent Claim
17 words
The method according to claim 6, wherein the radiation used for irradiation is far-ultraviolet rays or X-rays.
Claim 16
Dependent Claim
42 words
The method according to claim 13, wherein the alkaline solution used as solvent is an aqueous solution of a substance selected from the group consisting of sodium methasilicate, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium acetate, sodium oxalate, monoethanolamine, diethanolamine and triethanolamine.
Claim 17
Dependent Claim
15 words
The method according to claim 14, wherein the imide conversion reaction is accomplished by heating.
Claim 18
Dependent Claim
17 words
The method according to claim 14, wherein the imide conversion reaction is accomplished by tannic acid treatment.
Claim 19
Dependent Claim
109 words
The method according to claim 6, wherein the formation of the film is accomplished by heating an aqueous solution of poly(methacrylamide) or a polymethacrylamide copolymer containing other vinyl monomer units in an amount of up to 10 mol%, thereby converting said poly(methacrylamide) or polymethacrylamide copolymer into a crosslinked polymer including the following structural units: ##STR6## and having a C/N atomic ratio within the range of more than 4 and up to 6, or a copolymer thereof with another vinyl monomer, said copolymer containing the vinyl monomer units in an amount of up to 10 mol%, and coating the substrate with an aqueous solution of the converted polymer or copolymer.
Claim 20
Dependent Claim
21 words
The method according to claim 17, wherein heating is performed at a temperature of 70° to 100° C. in aqueous solution.
Claim 21
Dependent Claim
106 words
The method according to claim 6, wherein the formation of the film is accomplished by first forming on a substrate to be etched a film of poly(methacrylamide) or a polymethacrylamide copolymer containing other vinyl monomer units in an amount of up to 10 mol%, and then heating said film to convert said poly(methacrylamide) or polymethacryamide copolymer into a crosslinked polymer including the following structural units: ##STR7## and having a C/N atomic ratio within the range of more than 4 and up to 6, or a copolymer thereof with another vinyl monomer, said copolymer containing the vinyl monomer units in an amount of up to 10 mol%.
Claim 22
Dependent Claim
24 words
The method according to claim 19, wherein the average molecular weight of poly(methacrylamide) or its copolymer is within the range of 50,000 to 5,000,000.
Claim 23
Dependent Claim
27 words
The method according to claim 19, wherein heating is performed until the C/N ratio of the said produced polymer is within the range of 4.09 to 6.0.
Claim 24
Dependent Claim
18 words
The method according to claim 19, wherein heating is performed at a temperature of 180° to 270° C.
Claim 25
Dependent Claim
31 words
The method according to claim 22, wherein the incident charge of the electron beams is within the range of 2 × 10 -7 to 1 × 10 -3 coulomb/cm 2 .
Claim 26
Dependent Claim
26 words
The method according to claim 22, wherein the incident charge of far-ultraviolet rays or X-rays is within the range of 10.0 to 50,000 J/cm 3 .
References Cited (Backward Citations)
US3964908A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-23 | 1982-04-24 | 1982-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-23 | 1986-04-24 | 1986-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-23 | 1990-04-24 | 1990-10-24 | $7700.00 | Window Closed / Lapsed |