In the power module products, insulated materials, such as the insulated sheet used for them, are asked for high heat dissipation along with achievement of downsizing and high efficiency of the electronic equipment.
In order to give thermal conductivity to the thermosetting resin like epoxy resin, composite with high heat conduction ceramic filler, such as boron nitride (BN), is investigated. However, even if highly filled up with flake-like BN particles, the great improvement in the thermal conductivity of the thickness direction of the resin composite material is not obtained because BN particles orient in the field direction. On the other hand, if the orientation of BN particles was controlled by blending the aggregated BN filler, the thermal conductivity of the thickness direction could be greatly improved with lower filler content. The value of thermal conductivity was 18W/(m･K), and attained the thermal conductivity of the ceramic material level.
The novel transfer-molded power module (T-PM) structure module which applied the resin insulation composite material with the high heat conduction to the insulated sheet indicates excellent heat dissipation performance which exceeds the case type module using the AlN board.