Fabrication method of semiconductor device, evaluation method of semiconductor device, and semiconductor device

A fabrication method of a semiconductor device that includes a plurality of trench gate structures each having a gate electrode extending in a depth direction of an element, the plurality of trench gate structures including first trench gate structures respectively contributing to control of the element and second trench gate structures respectively not contributing to the control of the element, the fabrication method of a semiconductor device comprising:

• forming the plurality of trench gate structures on a front face of a semiconductor substrate;
• forming on the front face of the semiconductor substrate, an electrode pad connected to the gate electrode of at least one of the trench gate structures among the plurality of trench gate structures;
• executing screening by applying a predetermined voltage between the electrode pad and an electrode portion having a potential other than a gate potential, to apply the predetermined voltage to gate insulator films in contact with each gate electrode connected to the electrode pad;
• and
• forming the second trench gate structures respectively having the gate electrode connected to the electrode pad, by short-circuiting the electrode portion and the electrode pad to each other after executing screening.