Copolymer for positive type lithography, polymerization initiator used in production of said copolymer, and composition for semiconductor lithography

Abstract

A copolymer for positive type lithography, having at least a recurring unit (A) having a structure wherein an alkali-soluble group is protected by an acid-dissociating, dissolution-suppressing group, represented by the following formula (A) [in the formula (A), R10 is a hydrogen atom or a hydrocarbon group which may be substituted by fluorine atom; R11 is a crosslinked, alicyclic hydrocarbon group; n is an integer of 0 or 1; and R12 is an acid-dissociating, dissolution-suppressing group], and a terminal structure (B) having a structure wherein an alkali-soluble group is protected by an acid-dissociating, dissolution-suppressing group, represented by the following formula (B) [in the formula (B), R21 is a hydrocarbon group which may contain nitrogen atom; R22 is an acid-dissociating, dissolution-suppressing group; and p is a site of bonding with copolymer main chain].

Dependencies are inferred from the claim text.