Patent ID: 7223703

Claim:
A method of forming an N-layer mask pattern in N photosensitive layers (N≧2) formed on a substrate by exposure and development, comprising the steps of: stacking said N photosensitive layers on said substrate so that they becomes lower in sensitivity from the first photosensitive layer which is the bottom layer of said N photosensitive layers, toward the N th photosensitive layer; forming a first pattern of the same shape as a predetermined pattern to be formed on said substrate, in said first photosensitive layer; forming a K th pattern in the K th photosensitive layer (N≧K≧2) so that said K th pattern is smaller than a (K−1) st pattern formed in the (K−1) st photosensitive layer and arranged inside said (K−1) st pattern; and forming said N-layer mask pattern comprising said N photosensitive layers in which said first to N th patterns are formed.