Development of metal purifiers specific to lithography materials

Metal impurities in lithography materials are becoming a serious problem in leading-edge semiconductor device manufacturing. General ion-exchange type metal purifiers generally utilize a functional group with strong acidity. Since, various kinds of lithography materials are very sensitive to acidity, there is a risk of that acidity causing a deprotection reaction in chemically amplified resists, and hydration decomposition of ester solvents. In this paper, we will attempt to demonstrate that a novel membrane purifier called Nylonpolar can drastically reduce metal contaminants in organic solvents used for chemically amplified photoresists.