Method of manufacturing semiconductor device having a heat sink with a bored portion

A method of manufacturing a semiconductor device including a heatsink plate fixed to a substrate on which a semiconductor chip is mounted, so as to cover said semiconductor chip, comprising:

• preparing said substrate on which said semiconductor chip is mounted, and said heatsink plate including one or more through holes formed so as to communicate between a fixing surface thereof to be fixed to said substrate and a surface opposite to said surface;
• applying a first resin to said substrate on which said semiconductor chip is mounted;
• pressing said fixing surface, of said heatsink plate, against said first resin applied to said substrate;
• filling said through hole with a second resin;
• applying a third resin on said opposite surface in a larger diameter than said through hole so as to cover said through hole;
• and
• hardening said first to said third resins thereby fixing said heatsink plate to said substrate.