GRAY LEVEL MASK AND PREPARATION THEREOF

摘要

PURPOSE: To provide a gray level mask suitable for photolithoigraphy which consists of a transparent glass substrate bearing materials of plural levels having different optical transmittasbilities. CONSTITUTION: In the case of a mask using two levels alone, the first layer 24A thereof may be composed of glass formed to partially have transmittability by execution of substitution of silver ions in place of the metal ions of an alkaline metal silicate used in production of glass. The second layer 24B thereof may be formed opaque by constituting the layer of a metallic layer, such as chromium. The mask is constituted by the assistance of a photoresist constituting body 26 etched by a photolithographical masking operation in the specific regions in order to enable the selective etching operation with respect to the exposed regions of the materials of the levels having the different optical transmittabilies.