METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE AND ACTIVE MATRIX SUBSTRATE, AND ELECTRO-OPTIC DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor device and an active matrix substrate, and an electro-optic device, by which a variation in the LDD (lightly doped drain) length of a TFT is suppressed and displacement between a gate electrode and an LDD structure is eliminated so that deterioration due to aging can be prevented. SOLUTION: The method of manufacturing a semiconductor device comprises a gate electrode forming process for patterning an insulating film for a mask by using a resist film 204a as a mask to form a hard mask 203a and patterning a conductive film for forming a gate electrode by using the hard mask 203a pattern as a mask to form a gate electrode 5 smaller than the hard mask 203a pattern, a high-concentration impurity introducing process for introducing a high-concentration impurity into a silicon film 3 by using the hard mask 203a and the gate electrode 5 as a mask, and a low-concentration impurity introducing process for removing the hard mask 203a and introducing a low- concentration impurity into the silicon film 3 by using the gate electrode 5 as a mask.