| abstract |
Provided is an encapsulating resin composition for a power device including an epoxy resin, an inorganic filler, a curing agent, and a curing accelerator. This composition is molded under a condition of 175°C for 2 minutes and then subjected to after-curing under a condition of 175°C for 4 hours to obtain a test piece having a diameter of 100 mm and a thickness of 2 mm, and a half width of a current-time curve obtained by measuring the test piece with a thermally stimulated depolarization current method according to an order of (i) to (v) below is equal to or less than 800 seconds, (i) increase a temperature of the test piece to 150°C at a rate of 5°C/min without applying a voltage, (ii) applying a constant voltage of 500 V for 30 minutes while maintaining the temperature of the test piece at 150°C, (iii) lower the temperature of the test piece to 45°C at a rate of 5°C/min while applying the constant voltage of 500 V, (iv) stop applying the voltage while maintaining the temperature of the test piece at 45°C and leave the test piece to stand for 5 minutes, and (v) increase the temperature of the test piece at a rate of 3.5°C/min without applying a voltage to the test piece, and measure a value of a current flowing during the increase in the temperature to obtain a current-time curve. |