PREPARATION METHODS OF PHOTOMASK BLANK AND PHOTOMASK TO IMPROVE CHEMICAL RESISTANCE AND TO INHIBIT BENDING FOR SUPPRESSING CHANGE OF PHASE DIFFERENCE DUE TO ALKALI TREATMENT OF PHASE SHIFT LAYER

摘要

PURPOSE: A method for preparing a photomask blank and a method for preparing a photomask are provided, to inhibit bending and to improve chemical resistance for suppressing the change of phase difference due to the alkali treatment of a phase shift layer. CONSTITUTION: A photomask blank is prepared by forming at least one layer on a substrate; and irradiating the light by a flash lamp. Preferably the layer is formed by sputtering. Preferably the layer formed on the substrate has a transmissivity lower than that of the substrate, and the layer is a phase shift layer. Preferably the phase shift layer comprises silicone, at least one metal other than silicon, and at least one of oxygen, carbon and nitrogen. A photomask is prepared by forming a resist pattern on the layer of the photomask blank prepared by the method; etching it to remove the uncoated part of the resist; and removing the resist.