Method of manufacturing semiconductor device and semiconductor device having trench contact

A semiconductor device, comprising:

• a semiconductor substrate of a first conductivity type, the semiconductor substrate having a first main surface and a second main surface that are opposite to each other;
• a first semiconductor region of a second conductivity type selectively provided in the semiconductor substrate, at the first main surface of the semiconductor substrate, the first semiconductor region having a first surface and a second surface that are opposite to each other, the second surface facing the semiconductor substrate;
• a second semiconductor region of the first conductivity type, selectively provided in the first semiconductor region, at the first surface of the first semiconductor region;
• a trench that penetrates through the first semiconductor region and the second semiconductor region and reaches the semiconductor substrate;
• a gate insulating film provided in the trench, along a bottom and sidewalls of the trench;
• a gate electrode provided on the gate insulating film, in the trench;
• an interlayer insulating film that covers the gate electrode;
• a contact hole that penetrates through the interlayer insulating film and reaches the first semiconductor region;
• a third semiconductor region of the second conductivity type, provided in the first semiconductor region exposed at a bottom of the contact hole;
• a fourth semiconductor region of the second conductivity type, provided at the second surface of the semiconductor substrate;
• a first electrode provided on a surface of the first semiconductor region and a surface of the second semiconductor region;
• and
• a second electrode provided at a surface of the fourth semiconductor region, wherein
• in a horizontal direction parallel to the first main surface, the third semiconductor region has a width that is smaller than a width of a bottom of the contact hole, wherein
• the bottom and a sidewall of the contact hole form an angle θ in a range 84 degrees≤0<88 degrees.