Patent ID: 8530134
Filing Date: 2013-09-10
Classification: C08F,G03F

Abstract:
1. A process for producing a photoresist polymeric compound, the process comprising the steps of: carrying out polymerization of a monomer mixture containing at least one monomer selected from the group consisting of a monomer (a) containing a group capable of leaving with an acid to allow the polymeric compound to be soluble in an alkali, a monomer (b) having a lactone skeleton, and a monomer (c) having a hydroxyl-containing alicyclic skeleton, to give a polymer; passing a solution containing the polymer through a filter including a porous membrane having an anion-exchange group to give a polymer solution; and thereafter passing the polymer solution through a filter including a porous membrane having a cation-exchange group, wherein said passing through the two porous membrane filters in this order thereby reduces the metal content in the polymer solution, wherein the metal content in the polymer solution is sodium content or both sodium content and iron content, and wherein the polymer solution before the step of passing through the filter including a porous membrane having a cation-exchange group has a content of metals of 1000 parts per billion by weight or less per the weight of the polymer.