US Patent 7507622 Semiconductor device and manufacturing method thereof

A semiconductor device includes a semiconductor layer, an insulated-gate field effect transistor provided in the semiconductor layer, an etching stopper film provided above the insulated-gate field effect transistor, and an interlayer insulating layer provided above the etching stopper film; the insulated-gate field effect transistor including a gate insulating layer provided on the semiconductor layer, a gate electrode provided on the gate insulating layer, and an impurity region that constitutes a source region or a drain region provided in the semiconductor layer; wherein a removed region made by removing the etching stopper film is provided in at least part of an area that is located outside the gate insulating layer and above an area at a position other than a position sandwiched by the gate insulating layer and the impurity region.