Patent ID: 6190809
Filing Date: 2001-02-20
Classification: G03F

Abstract:
A method for fabricating a mask combining an attenuating phase shift part and an alternating phase shift part on the same mask blank, comprising:providing a mask blank comprising a transparent substrate on which has been sequentially deposited a first mask layer and a second mask layer;depositing on said mask blank a first layer of resist material;exposing said first layer of resist material with two deposition amounts of exposure energy, wherein a more deeply penetrating amount penetrates to the second mask layer, whereas the less deeply penetrating amount, outlines a shallow rim region;removing the exposed areas of the first resist layer by developing and baking;subjecting the exposed second mask layer to a dry etch, removing both the second mask layer and the first mask layer immediately below said second mask layer;applying a highly selective and anisotropic etch to the surface of the first resist layer, selectively etching down the shallow rim region to expose the second mask layer beneath it;etching away said second mask layer to expose the first mask layer surrounding the rim region;removing the remaining first resist layer;depositing a second resist layer on the mask;exposing said second resist layer to an exposure intensity sufficient to delineate the portions of the transparent substrate that will not phase shift;developing and baking the exposed regions of the second resist layer to expose the surface of the transparent substrate below;subjecting said surface of the optically transparent substrate to a dry etch to a depth of approximately 2700 angstroms below the surface of the substrate;removing the remaining second resist layer.