Patent ID: 8067516

Claim:
A method for production of a copolymer for positive type lithography, from a monomer capable of giving a recurring unit represented by the formula (A) in the formula (A), R 10 is a hydrogen atom or a hydrocarbon group of 1 to 4 carbon atoms which may be substituted by fluorine atom; R 11 is a crosslinked, alicyclic hydrocarbon group of 7 to 12 carbon atoms, crosslinked by a hydrocarbon group of 1 to 2 carbon atom, an oxygen atom or a sulfur atom; n is an integer of 0 or 1; and R 12 is an acid-dissociating, dissolution-suppressing group, wherein said method comprises: radical polymerizing the recurring unit (A) in the presence of a radical polymerization initiator represented by the formula (G) in the formula (G), R 71 and R 72 are each a hydrocarbon group of 3 to 6 carbon atoms which may contain nitrogen atom; R 73 and R 74 are each a hydrogen atom or an acid-dissociating, dissolution-suppressing group; and at least one of R 73 and R 74 is an acid-dissociating, dissolution-suppressing group; and introducing a terminal structure (B) having a structure wherein an alkali-soluble group is protected by an acid-dissociating, dissolution-suppressing group by radical polymerization in the presence of said radical polymerization initiator (G), wherein said terminal structure is represented by the following formula (B) in the formula (B), R 21 is a hydrocarbon group of 3 to 6 carbon atoms which may contain nitrogen atom; R 22 is an acid-dissociating, dissolution-suppressing group; and p is a site of bonding with copolymer main chain.