Method of manufacturing semiconductor device, method of manufacturing active matrix substrate, and electrooptic device

A method of manufacturing a semiconductor device comprising a first conduction type thin film transistor and a second conduction type thin film transistor which are formed on a substrate, the method comprising:

• the first gate insulating film forming step of forming a first gate insulating film on the surface of a semiconductor film which constitutes the thin film transistors;
• the first gate electrode forming step of forming a gate electrode forming conductive film on the surface of the first gate insulating film, and then patterning the gate electrode forming conductive film on the second conduction type thin film transistor side while leaving the gate electrode forming conductive film on the first conduction type thin film transistor side to form a gate electrode of the second conduction type thin film transistor;
• the high-concentration second conduction type impurity introducing step of introducing high-concentration second conduction type impurities into the semiconductor film using the gate electrode forming conductive film and the gate electrode of the second conduction type thin film transistor as a mask;
• the second gate electrode forming step of forming a pattering mask for the gate electrode forming conductive film on the surface of the gate electrode forming conductive film left on the first conduction type thin film transistor side, and patterning the gate electrode forming conductive film with the second thin film transistor side covered with the patterning mask to form a gate electrode of the first conduction type thin film transistor;
• and
• the first high-concentration first conduction type impurity introducing step of introducing high-concentration first conduction type impurities with the patterning mask left.