PHOTOMASK AS WELL AS PATTERN FORMATION USING THE PHOTOMASK, AND PRODUCTION OF FIELD EFFECT TRANSISTOR

摘要

PROBLEM TO BE SOLVED: To obtain a photomask which facilitates the production of compound semiconductor elements, etc., as well as a pattern formation method using the photomask, and a process for producing a field-effect transistor(FET). SOLUTION: This photomask is composed of a substrate 1 forming a first region A where the transmittance of light is largest, a second film 13 forming a second region C where the transmittance of light is smallest and a first film 12 forming a third region B which exists on the inner side of the second film 13 and where the transmittance of light is smaller than that of the first region A and larger than that of the second region C and the phase of the transmitted light varies from the phase of the light transmitted through the first region A. As a result, the photomask which facilitates the production of the compound semiconductor elements, etc., as well as the pattern formation method using the photomask and the process for producing the FET can be embodied.