# US 5,346,799 A · Novolak resins and their use in radiation-sensitive compositions wherein the novolak resins are made by condensing 2,6-dimethylphenol, 2,3-dimethylphenol, a para-substituted phenol and an aldehyde

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- Number: US 5,346,799 A
- Document ID: US5346799A
- Status: Granted
- Kind: A
- Application number: 07/986,223
- Filed: 1992-12-07
- Granted: 1994-09-13
- Earliest claimed: 1991-12-23
- Assignees: OCG Microelectronic Materials, Inc.
- Inventors: Alfred T. Jeffries, III; David J. Brzozowy
- Web page: https://patentgrep.com/patent/US5346799A

## CPC

- G03F 7/0236: {Condensation products of carbonyl compounds and phenolic compounds, e.g. novolak resins}
- C08G 8/04: of aldehydes
- 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)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

An alkali-soluble novolak binder resin made by the condensation reaction of a mixture of phenolic monomers with at least one aldehyde source, said phenolic monomers consisting of: (1) about 2-18% by weight of said mixture being 2,6-dimethylphenol; (2) about 55-75% by weight of said mixture being 2,3-dimethylphenol; (3) about 16-40% by weight of said mixture being a para-substituted lower alkyl phenol selected from the group consisting of 3,4-dimethylphenol, para-cresol, and para-cresol dimer; and the amount of said aldehyde source being at least a stoichiometric amount to react with all of said phenolic moieties. These novolak binder resins may be used in radiation-sensitive compositions useful as positive-working photoresists.

## Claims

### Claim 1

A radiation-sensitive composition useful as a positive-working photoresist dissolved in a solvent comprising an admixture of:
(A) a photoactive compound;
(B) an alkali-soluble novolak binder resin made by the condensation reaction of a mixture of phenolic monomers with at least one aldehyde source, said phenolic monomers consisting of:
(1) about 2-18% by weight of said mixture being 2,6-dimethylphenol;
(2) about 55-75% by weight of said mixture being 2,3-dimethylphenol; and
(3) about 16-40% by weight of said mixture being a para-substituted lower alkyl phenol selected from the group consisting of 3,4-dimethylphenol, para-cresol, and para-cresol dimer;
the amount of said aldehyde source being at least a stoichiometric amount to react with all of said phenolic moieties; and wherein the photoactive compound is from about 5% to about 40% by weight of the solids in said radiation-sensitive composition; and the alkali-soluble novolak resin is from about 95% to about 60% by weight of the solids in said radiation-sensitive composition.

### Claim 2

A radiation-sensitive composition useful as a positive-working photoresist dissolved in a solvent comprising an admixture of:
A. a photoactive compound; and
B. an alkali-soluble novolak binder resin made by the condensation reaction of a mixture of phenolic monomers with formaldehyde, said mixture of phenolic monomers consisting of:
(1) about 10-16% by weight of said mixture being 2,6-dimethylphenol;
(2) about 58-67% by weight of said mixture being 2,3-dimethylphenol; and
(3) about 22-35% by weight of said mixture being 3,4-dimethylphenol;
wherein the mole ratio of said formaldehyde to total phenolic moieties is at least about 1.01:1 to about 1.3:1; and wherein the photoactive compound is from about 5% to about 40% by weight of the solids in said radiation-sensitive composition, and the alkali-soluble novolak resin is from about 95% to about 60% by weight of the solids in said radiation-sensitive composition.

### Claim 3 (depends on 1)

The radiation-sensitive composition of claim 1 wherein the percentage of said 2,6-dimethylphenol is from about 10% to about 16% by weight of said phenolic mixture.

### Claim 4 (depends on 1)

The radiation-sensitive composition of claim 1 wherein the percentage of said 2,3-dimethylphenol is from about 58% to about 67% by weight of said phenolic mixture.

### Claim 5 (depends on 1)

The radiation-sensitive composition of claim 1 wherein the percentage of said para-substituted lower alkyl phenol is from about 22% to about 35% by weight of said phenolic mixture.

### Claim 6 (depends on 1)

The radiation-sensitive composition of claim 1 wherein said para-substituted lower alkyl phenol is 3,4-dimethylphenol.

### Claim 7 (depends on 1)

The radiation-sensitive composition of claim 1 wherein the mole ratio of said aldehyde source to total phenolic moieties is at least about 1.01:1 to about 1.3:1.

### Claim 8 (depends on 1)

The novolak resin of claim 1 wherein said aldehyde source is formaldehyde.