Patent ID: 9216948
Filing Date: 2015-12-22
Classification: B01D,C07B,C07C,C08F

Abstract:
1. A method for producing a polymer for semiconductor lithography, said polymer comprising at least one type of repeating units selected from the group consisting of a repeating unit having a hydroxy group or carboxy group (A), a repeating unit having a structure wherein a hydroxy group or carboxy group is protected with a group that suppresses dissolution into an alkaline developer and is dissociable by the action of an acid (B), a repeating unit having a lactone structure (C), and a repeating unit having a cyclic ether structure (D), said method comprising: a filtering step, wherein a solution of a polymerization initiator dissolved in an organic solvent is passed through a filter having a pore size of not more than 1.0 μm to reduce a sodium content of said polymerization initiator solution to not more than 300 ppb with respect to a weight of said polymerization initiator to produce a purified polymerization initiator; and a polymerization step wherein said polymer for semiconductor lithography is synthesized, in the presence of said purified polymerization initiator that was purified by said filtering step, by a radical polymerization reaction.