Semiconductor device and method of manufacturing semiconductor device

A method of manufacturing a semiconductor device, comprising:

• a step (a) of forming a first element isolation trench defining a first active region in a first region in a semiconductor substrate and a second element isolation trench defining a second active region in a second region in the semiconductor substrate, forming a first element isolation region by burying the inside of the first element isolation trench with a first insulating film, and forming a second element isolation region by burying the inside of the second element trench with the first insulating film;
• a step (b) of making a surface of the first element isolation region receded;
• a step (c) of forming first and second gate electrode parts over the first active region;
• a step (d) of forming a dummy electrode part which replaces a third gate electrode part over the second active region and is made by a film in the same layer as the first gate electrode part;
• a step (e) of forming a second insulating film over the first gate electrode part, the second gate electrode part, and the dummy electrode part;
• a step (f) of etching the second insulating film until the dummy electrode part is exposed, and
• a step (g) of forming the third gate electrode part by removing the exposed dummy electrode part.