Abstract: A protective film-forming composition including good mask (protection) function against a wet etching liquid and a high dry etching rate during processing of semiconductor substrates, including good coverage even in stepped substrates, and from which flat films can be formed due to a small difference in film thickness after embedding; a protective film produced using said composition; a substrate with a resist pattern; and a method for manufacturing a semiconductor device. A protective film-forming composition which protects against a semiconductor wet etching liquid, wherein a reaction product (P) of a diepoxy compound (B) and an bifunctional proton-generating compound (C) contains a structure represented by formula (1) (in formula (1), Ar represents a C6-40 aryl group, n represents an integer of 2-10, —Y— represents —OCO—, —O— or —S—, and * represents the bonding site with the reaction product (P) molecule terminal). The protective film-forming composition further includes an organic solvent (S).

Abstract: Provided is a method for producing a polymer, comprising: a first step for synthesizing a crude polymer by reacting a monomer containing a pyrimidinetrione structure, an imidazolidinedione structure, or a triazinetrione structure, in an organic solvent in the presence of a quaternary phosphonium salt or quaternary ammonium salt; and a second step for precipitating and separating a purified polymer by mixing a poor solvent with the crude polymer-containing solution obtained in the first step.

Abstract: Provided is a composition which is for forming a resist underlayer film and with which the amount of a sublimate derived from a low-molecular-weight component such as an oligomer can be reduced, the composition comprising, for example, an organic solvent and a polymer having a repeating unit represented by formula (1-1), wherein the content of a low-molecular-weight component having a weight average molecular weight of 1,000 or less is 10 mass % or less in the polymer.

Abstract: A protective film-forming composition including good mask (protection) function against a wet etching liquid and a high dry etching rate during processing of semiconductor substrates, including good coverage even in stepped substrates, and from which flat films can be formed due to a small difference in film thickness after embedding; a protective film produced using said composition; a substrate with a resist pattern; and a method for manufacturing a semiconductor device. A protective film-forming composition which protects against a semiconductor wet etching liquid, wherein a reaction product (P) of a diepoxy compound (B) and an bifunctional proton-generating compound (C) contains a structure represented by formula (1) (in formula (1), Ar represents a C6-40 aryl group, n represents an integer of 2-10, —Y— represents —OCO—, —O— or —S—, and * represents the bonding site with the reaction product (P) molecule terminal). The protective film-forming composition further includes an organic solvent (S).