Method and device for inspecting junction portion of power module

A method for inspecting a junction portion of a power module, the method comprising:

• measuring a primary voltage, by a voltage sensor, for the power module;
• applying a heating current to the power module, by a current applying equipment, to heat the power module;
• releasing, by a processing unit, the heating current and simultaneously measuring, by the voltage sensor a secondary voltage for the power module;
• cooling the power module, by the processing unit;
• calculating, by the processing unit, a temperature change amount based on the measured value of the primary voltage and the measured value of the secondary voltage;
• calculating, by the processing unit, thermal resistance based on an amount of power applied to the power module and the calculated amount of temperature change;
• and
• determining, by the processing unit, whether the junction portion of the power module is defective, based on the calculated thermal resistance.