A power module for an electric motor has at least one semiconductor switch half bridge with a high-side semiconductor switch and a low-side semiconductor switch. The semiconductor switches of the semiconductor switch half bridge have contact gap terminals which are each formed by a flat surface region of the semiconductor switch and which each point in the same direction. The high-side semiconductor switch and the low-side semiconductor switch enclose between them a circuit carrier that has at least two electrically conductive layers. A contact gap terminal of the low-side semiconductor switch and a contact gap terminal of the high-side semiconductor switch of the half bridge are electrically connected to each other by the circuit carrier.

An insulating film is formed such that the insulating film covers a source electrode and a gate electrode, and an opening portion exposing a portion of the source electrode and an opening portion exposing a portion of the gate electrode are formed in the insulating film. A plated layer is formed over the source electrode exposed in the opening portion, and a plated layer is formed over the gate electrode exposed in the opening portion. A source pad is formed of the portion of the source electrode exposed in the opening portion, and the plated layer, and a gate pad is formed of the portion of the gate electrode exposed in the opening portion, and the plated layer. An area of the opening portion for the gate pad is smaller than an area of the opening portion for the source pad, and a thickness of the plated layer over the gate electrode is greater than a thickness of the plated layer over the source electrode.

A heating method includes an oxide film forming step and a heating step. The thickness of an oxide film is set in a first range that includes a first maximal thickness and a second maximal thickness and that is smaller than a second minimal thickness in the relationship with the laser absorption having a periodic profile. The first maximal thickness corresponds to a first maximal value a of the laser absorption. The second maximal thickness corresponds to a second maximal value of the laser absorption. The second minimal thickness corresponds to a second minimal value of the laser absorption, namely the minimal value of the laser absorption that appears between the second maximal value and a third maximal value, or the maximal value of the laser absorption that appears subsequent to the second maximal value.

A heating method includes an oxide film forming step and a heating step. The thickness of an oxide film is set in a first range that includes a first maximal thickness and a second maximal thickness and that is smaller than a second minimal thickness in the relationship with the laser absorption having a periodic profile. The first maximal thickness corresponds to a first maximal value a of the laser absorption. The second maximal thickness corresponds to a second maximal value of the laser absorption. The second minimal thickness corresponds to a second minimal value of the laser absorption, namely the minimal value of the laser absorption that appears between the second maximal value and a third maximal value, or the maximal value of the laser absorption that appears subsequent to the second maximal value.