Abstract
Next generation power semiconductors, e.g. SiC and GaN, are emerging for the further minimization and high current/voltage of power devices with high reliability covering wider operating environments than those based on Si. To implement high reliability operation, the key technology is the control of the temperature distribution in the module, and thermal stress caused by the heat generated by power loss. In the present study, we have developed SiC micro-heater chip with temperature probe to evaluate thermal characteristics of an assembled system of Ag sinter die-attach on metalized ceramic substrate (Cu/Si3N4/Cu) during the repetitive power cycling. The test specimens were fixed on a water cooling system, and steady-state heat resistance of the system was measured during the power cycling. For comparison, Pb-Sn, Sn-Cu-Ni-P, Sn-Ag-Sb-Cu solders were used as die-attach material bonded on the same metalized ceramic substrates. The maximum applied power exceeds 200 W with cycles of 2 seconds of heating and 5 seconds of cooling, and the test cycles was over 5000 cycles. The power cycle number dependence on the temperature swing and thermal resistance characteristics would be discussed, in connected with the power cycle testing for real power devices.
