Mask structure and method of making the same

Abstract

A method of manufacturing a mask in which laser radiation is projected to a mask substrate of silicon and a supporting frame of heat resisting glass, while a voltage of about 1000-10000 V is applied between the mask substrate and the supporting frame. Cooling water is caused to flow to suppress temperature rise due to the irradiation, to maintain the mask substrate and the supporting frame at a predetermined normal temperature (about the mask temperature in a lithographic pattern transfer process). The light projecting step is performed for a period not shorter than 10 minutes whereby anodic bonding of the mask substrate with the supporting frame is achieved. This prevents a shift of the mask pattern and/or deformation of the mask substrate, and it assures the manufacture of a high precision mask.

Dependencies are inferred from the claim text.