Exposure mask, exposure mask substrate, method for fabricating the same, and method for forming pattern based on exposure mask

摘要

An exposure mask having an excellent alignment accuracy between patterns, which is prepared by first forming on a light transmissive substrate a light shielding film or a semi-transparent film pattern (first pattern) somewhat larger than a desired dimension, forming thereon a semi-transparent film or a light transmissive film pattern (second pattern) so as to include all patterns of the desired dimensions made up of a light shielding part, a semi-transparent part and a light transmissive part, and then removing a projected part of the first pattern with use of the second pattern as a mask. The semi-transparent film is formed of at least two layers each of which contains a common element, thus the semi-transparent film can be made with use of the same apparatus and when patterning, etching process can be carried out with use of the same etchant. Further, since in a mask including the semi-transparent pattern, at least that area of a non-pattern zone where light reaches a wafer through the transfer, acts to shield the exposure light, too narrowed pattern or insufficient focal depth can be prevented.