Abstract: Phenolic compound (a) is polycondensed with mixed aldehyde (b) consisting essentially of 5-30 mol % of unsaturated aliphatic aldehyde (b-1) and 70-95 mol % of saturated aliphatic aldehyde (b-2) to give alkali-soluble novolak resin (A) as the product of polycondensation reaction. The alkali-soluble novolak resin (A) is used with quinonediazido group containing compound (B) to produce a positive photoresist composition. According to the present invention, there are specifically provided a positive photoresist composition that has high feature integrity in spite of high sensitivity and which yet provides a great depth of focus, a process for producing such positive photoresist composition, as well as an alkali-soluble novolak resin that can advantageously be used in such composition, and a method of forming patterns with high reproducibility using such positive photoresist composition.

Abstract: A positive photoresist coating solution comprising (a) an alkali-soluble resin, (b) a quinone diazide group-containing compound, and (c) an organic solvent in an amount sufficient for dissolving said (a) and (b) components, wherein said organic solvent contains (i) propylene glycol monopropyl ether and (ii) 2-heptanone. The solution of the present invention exhibits excellent coating ability, sensitivity, thermostability, focal depth range, shape-profiling ability, and the like.

Abstract: Proposed is an improved positive-working photoresist composition for use in the photolithographic patterning works for the manufacture of semiconductor devices, which is capable of giving a patterned resist layer on a substrate surface having excellent resolution and heat resistance without formation of scum in the development treatment. The photoresist composition comprises: (a) an alkali-soluble novolac resin as a film-forming ingredient and (b) a naphthoquinone diazide group-containing compound as a photosensitizing ingredient, of which the novolac resin is a condensation product of a phenolic compound and an aldehyde compound, the condensation reaction being undertaken in a solvent system containing, in addition to water, .gamma.-butyrolactone or a combination of .gamma.-butyrolactone and a propyleneglycol monoalkyl ether in a limited proportion.

Abstract: A positive-working photosensitive resin composition useful as a photoresist material in the fine patterning work for the manufacture of semiconductor devices is proposed. The composition is excellent in the storage stability and capable of giving a patterned resist layer having good film thickness retention, cross sectional profile of line patterns, resolution and heat resistance. The composition comprises, in addition to a conventional alkali-soluble novolac resin as a film-forming agent and a quinone diazide group containing compound as a photosensitizing agent, a specific isocyanurate compound substituted at each nitrogen atom with a hydroxy- and ter-butyl-substituted benzyl group.