METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE, METHOD FOR MANUFACTURING ACTIVE MATRIX SUBSTRATE AND ELECTROOPTICAL DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device of a stable LDD structure in which the number of steps is simplified, and a misalignment of a gate electrode and the LDD structure is eliminated, and there is no fear of an age-based deterioration of characteristics; a method for manufacturing an active matrix substrate; and an electrooptical device. SOLUTION: The present invention comprises the steps of: forming a gate oxide film 4, a gating conductive film 202 and a resist film 203 on a polysilicon film 3; patterning the gating conductive film 202 by use of a mask 203a of this resist to form a masking conductive film 202a having the substantially same pattern as that of the mask 203a; introducing a high concentration impurity into a polysilicon film 3 by use of the mask 203a and the masking conductive film 202a; selectively removing both side parts of the masking conductive film 202a to form a smaller gate electrode than the pattern of the mask 203a; and removing the mask 203a to introduce a low concentration impurity into a polysilicon film 3 with the gate electrode as a mask.