Fabrication of self-aligned attenuated rim phase shift mask

Abstract

This invention provides a method of forming an attenuating phase shifting rim type photomask and an attenuating phase shifting rim type photomask for use in projection type lithographic apparatus. The photomask is formed by exposing a layer of negative photoresist through a second surface of a transparent mask substrate having a patterned layer of attenuating phase shifting material formed on a first surface of the transparent mask substrate. The exposed and developed photoresist forms a pedestal with sloping sides. A layer of opaque material is vertically anisotropically deposited on the top of the pedestal and that part of the patterned layer of attenuating phase shifting material not shaded by the pedestal. The pedestal and opaque material formed on the top of the pedestal is then removed to complete the mask.