A semiconductor module includes a base plate, at least one semiconductor chip mounted on the base plate, a case fixed to the base plate and surrounding the at least one semiconductor chip, an electrically insulating gel layer covering the at least one semiconductor chip, a thermosetting resin layer formed on top of the gel layer, and a lid formed on top of the thermosetting resin layer. The lid comprises a lid-extension, which defines a lid-opening. The lid-opening extends through the thermosetting resin layer to the gel layer and allows gel of the gel layer to expand into the lid-opening.