METHOD FOR REMOVING METAL ION IMPURITY IN POLYMER COMPOUND FOR PHOTOLITHOGRAPHY

摘要

PROBLEM TO BE SOLVED: To provide a method for efficiently removing metal ion impurities or gel particles without causing changes in the chemical structures of a polymer compound suitably in use for compositions for photoresists or anti-reflection films due to the reaction with strongly acidic ion exchange groups.

SOLUTION: The invention relates to a method for removing metal ion impurities in a solution containing a polymer compound with a crosslinking agent attached to its side chains. The method includes passing the solution through not less than one filter which does not contain strong acid ion exchange groups in the filter medium and contain charge controllers generating zeta potential.

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