A power semiconductor device comprising a power semiconductor module and a heat sink; and a method for its manufacture. The module has a cooling plate, with an opening delimited by a lateral first surface thereof extending circumferentially around the opening. The cooling plate is arranged in the opening and has a lateral first surface which extends circumferentially around the cooling plate. The two first surfaces are at a respective angle of less than 90 DEG with respect to a main surface of the cooling plate facing the power semiconductor components. The two first surfaces are pressed together, extending circumferentially along the first surface of the cooling plate and extending circumferentially along the first surface of the heat sink. The inventive power semiconductor device has good heat conduction from the power semiconductor components to the heat sink through which a liquid can flow, and which is reliably leaktight over the long term.