US 4,731,319 AGranted

Positive-working naphthoquinone diazide photoresist composition with two cresol novolac resins

AssigneeTokyo Ohka Kogy Co., Ltd.

InventorsHidekatsu Kohara, Hatsuyuki Tanaka, Masanori Miyabe, Yoshiaki Arai, Shingo Asaumi, Toshimasa Nakayama

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Abstract

A positive-working photoresist composition suitable for fine patterning in the manufacture of semiconductor devices, e.g. VLSIs, with high fidelity is proposed. The composition comprises a cresol novolac resin and a naphthoquinone diazide sulfonic acid ester as the photosensitive component while the cresol novolac resin component is characteristically a combination of two different cresol novolac resins differentiated in respects of the weight-average molecular weight, one large and the other small, and the weight proportion of the m- and p-isomers of cresol, one rich in the m-isomer and the other rich in the p-isomer, used in the preparation of the novolac and the overall weight ratio of the m-cresol and p-cresol moieties in the thus combined cresol novolac resins also should be in a specified range.

Claims2

Dependent claims

A positive-working photoresist composition which comprises an admixture of:

(A) 100 parts by weight of a cresol novolac resin as a film-forming constituent;
and
(B) from 25 to 60 parts by weight of a naphthoquinone diazide sulfonic acid ester as a photosensitive constituent, the cresol novolac resin being a combination composed of:
(A-1) a first cresol novolac resin having a weight-average molecular weight of at least 5000 and produced from an isomeric mixture consisting essentially of 60 to 80% of m-cresol and 40 to 20% of p-cresol;
and
(A-2) a second cresol novolac resin having a weight-average molecular weight not exceeding 5000 and produced from an isometric mixture consisting essentially of 10 to 40% of m-cresol and 90 to 60% of p-cresol
in such a proportion that the overall cresol moiety in the component (A) is comprised of from 30 to 46.5% of the m-cresol moiety and from 70 to 53.5% of the p-cresol moiety.

4 more elements

Dependencies are inferred from the claim text.