Semiconductor device and manufacturing method

A semiconductor device including a first semiconductor region with a second conductivity type formed on a side of a front surface of a semiconductor substrate with a first conductivity type and a second semiconductor region with the first conductivity type selectively formed on closer to a portion of the side of the front surface than the first semiconductor region, the semiconductor device comprising:

• a plurality of trenches extending in a predetermined extension direction in the side of the front surface of the semiconductor substrate and reaching below the first semiconductor region;
• a conducting portion filled within the plurality of trenches;
• an interlayer insulating film covering the front surface of the front surface of the semiconductor substrate with a prescribed pattern;
• a first electrode connecting to the semiconductor substrate via a region exposed from the interlayer insulating film in a mesa region sandwiched between the trenches, wherein
• in a cross section perpendicular to the extension direction, a first trench portion and a second trench portion are provided, the first trench portion having a predetermined distance from the front surface of the semiconductor substrate to a deepest portion on a surface of the conducting portion, and the second trench portion having a predetermined distance from the front surface of the semiconductor substrate to a deepest portion on the surface of the conducting portion, and
• each of the trenches in the first trench portion and the second trench portion includes, on a top end, a shoulder portion having a slope toward the exposed region, greater than a slope of a side wall of the trench.