Patent ID: 7862983

Claim:
A composition of matter derived from a method of making a stable polymer from a solution of a polymer containing trace metals, said method which consists of: (a) providing a polymer solution containing a polymer, a first solvent and trace materials; (b) passing said polymer solution through an acidic cation ion echange material to remove said trace metals thereform and thereby forming a polymer solution containing free acid radcials: (c) precipitating said polymer from said polymer solution of step b by contacting with a second solvent wherein the polymer is substantially insoluble therein; (d) filtering said solution and said second solvent to thereby form a solid polymer cake; (e)contacting said cake from step d with sufficient quantities of additional said second solvent in order to remove free acid radicals thereform; (f) adding a compatible photoresist solvent to said polymer cake from step e and mixing the two in order to dissolve said polymer in said photoresist solvent and thereby forming a photoresist solution; and (g) removing any residual first and second solvents from said polymer to form a stable polymer.