# US 4,395,482 A · Method for the preparation of heat-resistant relief structures using positive resists

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- Number: US 4,395,482 A
- Document ID: US4395482A
- Status: Granted
- Kind: A
- Application number: 06/372,540
- Filed: 1982-04-28
- Granted: 1983-07-26
- Earliest claimed: 1979-08-01
- Assignees: Siemens Aktiengesellschaft
- Inventors: Hellmut Ahne; Eberhard Kuhn; Roland Rubner
- Web page: https://patentgrep.com/patent/US4395482A

## CPC

- G03F 7/0233: {characterised by the polymeric binders or the macromolecular additives other than the macromolecular quinonediazides}
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)

## Abstract

The invention relates to heat-resistant positive resists based upon precursor stages of highly heat-resistant polymers and light-sensitive diazoquinones, as well as to a method for preparing heat-resistant relief structures of such positive resists. The positive resists of the type mentioned are developed in such a manner that they are heat-resistant as well as have a long storage life and are easily processed. The invention provides for the use of oligomer and/or polymer precursor stages of polyoxazoles in the form of polycondensation products of aromatic and/or heterocyclic dihydroxydiamino compounds and dicarboxylic acid chlorides or esters. The positive resists according to the invention are suitable especially for applications in microelectronics.

## Claims

### Claim 1

A method for the preparation of heat-resistant relief structures, comprising:
(a) applying to a substrate, in the form of a layer or foil, a heat-resistant positive resist comprised of (1) a precursor of a highly heat-resistant polymer and (2) a light-sensitive diazoquinone, said precursor comprising an oligomeric and/or polymeric precursor of a polyoxazole in the form of a polycondensation product of an aromatic and/or heterocyclic dihydroxydiamino compound and a dicarboxylic acid chloride or a dicarboxylic acid ester;
(b) generating exposed or irradiated portions on said resist by treating said resist by a method selected from the group consisting of (1) exposing said resist through a mask with actinic light and (2) irradiating said resist by deflection of a light, electron or ion beam;
(c) removing the exposed or irradiated portions from said layer or foil; and
(d) annealing the relief structure so obtained.

### Claim 2 (depends on 1)

A method according to claim 1 wherein said positive resist is dissolved in an organic solvent for application to the substrate.

### Claim 3 (depends on 2)

A method according to claim 2 wherein said solvent comprises N-methylpyrrolidone.

### Claim 4 (depends on 1)

A method according to claim 1 wherein said substrate comprises a member selected from the group consisting of glass, metal, plastic and semiconductor material.

### Claim 5 (depends on 1)

A method according to claim 1 wherein said relief structure is annealed by heating to a temperature above 200.degree. C.

### Claim 6 (depends on 5)

A method according to claim 5 wherein said temperature is between about 300.degree. and 350.degree. C.

### Claim 7 (depends on 1)

A method according to claim 1 wherein the annealed relief structure is dissolved off the substrate and transferred to another substrate.