Manufacturing method of semiconductor device

A manufacturing method of a semiconductor device comprising the steps of:

• (a) preparing a mold die including an upper die having an upper die cavity block, a lower die having a lower die cavity block and push-up pins, and a pot block having a pot that supplies resin;
• (b) preparing a semiconductor chip mounted over an upper surface of a substrate;
• (c) disposing the substrate over a surface of the lower die cavity block;
• (d) clamping the substrate between the upper die and the lower die so that the semiconductor chip is located in an upper die cavity of the upper die cavity block;
• (e) supplying the resin into the upper die cavity from the pot of the pot block to seal the semiconductor chip with resin;
• and
• (f) inserting each push-up pin into a hole formed in the rear surface opposite to the surface of the lower die cavity block and pressing the same against an inner wall of the hole to return the lower die cavity block sunk in the step (d) to the initial position,
• wherein a part of a side surface of the hole into which each push-up pin is inserted is inclined to the direction in which the diameter of the hole becomes smaller from the rear surface side of the lower die cavity block towards the surface side.