Patent ID: 8377625

Claim:
A method for production of a copolymer solution for semiconductor lithography, said copolymer solution consisting essentially of a copolymer and a solvent for coating film formation, said copolymer containing at least one repeating unit selected from the group consisting of: a repeating unit (A) having a hydroxyl group; a repeating unit (B) having a structure in which a hydroxyl group is protected by a group which suppresses dissolution into an alkaline developer and which dissociates in the action of an acid; a repeating unit (C) having a lactone structure and a repeating unit (D) having a cyclic ether structure; said method comprising a step (S) of heating said copolymer solution under reduced pressure to distill off impurities whose boiling points are lower than that of said solvent for coating film formation; a step (U) of stirring said copolymer solution after said step (S) using a bath different from one used in said step (S) to uniformize the concentration of the copolymer in said copolymer solution; and a step (W) of filling said copolymer solution after step (U) into a plurality of containers, wherein the difference between the maximum value and minimum value of the concentration of said copolymer between said containers is not more than 1.5% of the maximum concentration.