| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for purifying a copolymer, which can remove a constituent with low solubility in a lithography solvent or the like, which is a factor of deteriorating lithography performance; and to provide a copolymer obtained by the purification method. <P>SOLUTION: The method for purifying a copolymer includes steps of: dissolving a copolymer for lithography in a good solvent to prepare a copolymer solution; adding a poor solvent, in which the copolymer is not dissolved but which is compatible with the good solvent and has a value of a solubility parameter, according to a method of Fedors, of 18 MPa<SP POS="POST">1/2</SP>or less, to the copolymer solution in the poor solvent range of no deposition of the copolymer is not separated (poor solvent addition step); and filtrating the copolymer solution after the poor solvent addition step. <P>COPYRIGHT: (C)2012,JPO&INPIT |
