| 摘要 |
A power module is provided with a copper layer composed of copper or a copper alloy on a surface of a circuit layer (12) to which a semiconductor device (3) is bonded, and a solder layer (20) that is formed by using a solder material is formed between the circuit layer (12) and the semiconductor device (3). An average crystal grain size which is measured by EBSD measurement in a region having a thickness of up to 30 µm from the surface of the circuit layer (12) in the solder layer (20) is 10 pm or less, the solder layer (20) has a composition that contains Sn as a main component, 0.01 to 1.0% by mass of Ni, and 0.1 to 5.0% by mass of Cu, and a thermal resistance increase rate when a power cycle is loaded 100,000 times under conditions of a conduction duration of 5 seconds and a temperature difference of 80°C is less than 10% in a power cycle test. |
