METHOD FOR CLEANING PHOTOMASK-FORMING GLASS SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To provide a method for cleaning a photomask-forming glass substrate having a principal surface polished chemically and mechanically by using a polishing agent, in which method the polishing agent can be removed quickly from the chemically/mechanically-polished principal surface of the glass substrate for photomasks.SOLUTION: The method for cleaning a photomask-forming glass substrate having a principal surface polished chemically and mechanically by using a polishing agent, comprises the steps of: executing such treatment at least once that a sign of a zeta potential of the polishing agent is inverted after executing chemical mechanical polishing; and physically cleaning the principal surface of the glass substrate for photomasks.