Power semiconductor module and manufacturing method thereof

A power semiconductor module, comprising:

• a circuit board formed of a metal base plate, a thermally conductive insulating layer joined to a face of the metal base plate on one side, and a wiring pattern provided to a face of the thermally conductive insulating layer on a side opposite to the face joined to the metal base plate;
• a power semiconductor element joined to an element mount portion of the wiring pattern;
• a tubular external terminal connection body provided to the wiring pattern, to which an external terminal is connected by insertion;
• and
• a transfer mold resin body encapsulated in such a manner that a face of the metal base plate on an other side opposite the thermally conductive layer and a top portion of the tubular external terminal connection body are exposed, and the one side and side faces of the metal base plate, the power semiconductor element, and the tubular external terminal connection body are covered,
• wherein:
• the metal base plate is provided with a through-hole and an attachment member placed in the through-hole and fixing a cooling fin to the face of the metal base plate on the other side;
• and
• the transfer mold resin body is provided with an insertion hole for the attachment member communicating with the through-hole and having a diameter larger than a diameter of the through-hole,
• wherein the insertion hole is formed to open also to a side face of the transfer mold resin body.