Abstract: There is provided a process for preparing a polymer compound for a resist, which can improve the performance, such as the heat resistance, sensitivity and resolution of the resist, without causing film loss of the resist, line width reduction of the resist or deterioration of the dry etching resistance of the polymer. This process comprises dissolving a styrene-based monomer containing at least a 4-acetoxystyrene monomer, and a dimethyl-2,2′-azobiscarboxylate ester in a solvent, thereby to polymerize the styrene-based monomer; adding an alkali catalyst to the resulting polymer solution, thereby to hydrolyze the polymer solution; and washing the resulting polymer compound with water.

Abstract: The present invention relates to a novolak type phenol resin, in particular a novolak type phenol resin for resists suitable for forming resist patterns. The novolak type phenol resin of the present invention is obtained by reacting at least a vinylphenol having a vinyl group and a phenolic hydroxyl group, such as parahydroxystyrene, or a polyvinylphenol, which is a polymer of the vinylphenol, a compound (A) such as 4,4′-methylenebis(2-hydroxymethyl-3,6-dimethylphenol) and/or a compound (B) such as 2,6-dihydroxymethyl-4-phenol, in a ratio of 1 to 40 moles of the compound (A) and/or compound (B) to 100 moles of the vinylphenol or 100 moles of structural unit of the vinylphenol contained in the polyvinylphenol in the presence of an acid and having a weight average molecular weight of 2,000 to 20,000. Such a novolak type phenol resin provides good pattern shape, heat resistance, resolution, and sensitivity in resists for lithography.

Abstract: The present invention relates to a phenol resin, in particular a phenol resin for resists suitable for forming resist patterns. The phenol resin of the present invention is obtained by reacting at least two components, i.e., a compound (A) such as 4-hydroxymethyl-2,6-dimethylphenol and a polymerizable phenol compound such as parahydroxystyrene or a polymer (B), which is a polymer of the polymerizable phenol compound, in a ratio of 1 to 50 moles of the compound (A) to 100 moles of the polymerizable phenol compound or 100 moles of structural unit of the polymerizable phenol compound contained in the polymer (B) in the presence of an acid and having a molecular weight of 2,000 to 20,000. Such a phenol resin provides good pattern shape, heat resistance, resolution, and sensitivity in resists for lithography.