Patent ID: 9601404
Date: 2017-03-21
CPC Classifications: G01R,H01L

Claim:
1. A thermal resistance measuring method, comprising: measuring an exterior temperature of a semiconductor device housing a semiconductor element wherein current is caused to flow from a third electrode of the semiconductor element to a second electrode of the semiconductor element in accordance with a voltage applied between a first electrode of the semiconductor element and the second electrode; inputting a constant current such that the semiconductor element does not generate heat, measuring a second voltage between the first electrode and second electrode, which is controlled so that a first voltage between the third electrode and second electrode is constant, and calculating the element temperature of the semiconductor element based on the second voltage and on a temperature coefficient relating to the second voltage; causing a constant current such that the semiconductor element generates heat to be input between the third electrode and second electrode, with a third voltage applied between the first electrode and second electrode kept constant; calculating a power based on the current such that the semiconductor element generates heat, and on a fourth voltage between the third electrode and second electrode when the semiconductor element generates heat; inputting a constant current of an extent such that the semiconductor element does not generate heat, measuring a fifth voltage between the first electrode and second electrode, which is controlled so that the first voltage between the third electrode and second electrode is constant, and calculating the element temperature of the semiconductor element based on the fifth voltage and on a temperature coefficient relating to the fifth voltage; measuring the exterior temperature of the semiconductor element after heat is generated; and calculating a thermal resistance value of the semiconductor element based on the amount of change in the exterior temperature and the amount of change in the element temperature of the semiconductor element before and after heat is generated, and on the power.