Patent ID: 10047186

Abstract:
The present invention provides a photosensitive composition having excellent heat resistance, low absorbance at the exposure light at wavelengths of g-line, h-line, and i-line, and satisfactory sensitivity even when the thickness of a resist film is increased, and also provides a resist material, a coating film thereof, a novolac phenol resin suitable for these applications, and a method for producing the phenol resin. Specifically, there is provided a novolac phenol resin produced by reacting a phenolic trinuclear compound (A) with formaldehyde under an acid catalyst, the phenolic trinuclear compound (A) including a phenolic trinuclear compound (A1) produced by condensation reaction of dialkyl-substituted phenol with a hydroxyl group-containing aromatic aldehyde and a phenol trinuclear compound (A2) produced by condensation reaction of dialkyl-substituted phenol having alkyl groups at the 2- and 3-positions, 2- and 5-position, the 3- and 4-positions, or 3- and 5-positions with an aromatic aldehyde not having a hydroxyl group, wherein the molar ratio of the phenolic trinuclear compound (A1) to the phenolic trinuclear compound (A2) is 20:80 to 90:10.