Extreme Low Interfacial Thermal Resistance Heat Conductive Sheet Design

Abstract

High thermal conductive adhesive is important to cool power devices. Recently thermal conductivity reaches more than 10W/mK by efficient addition of thermal conductive filler(1). However, high loading of filler makes the thermal conductive sheet poor adhesion. In order to have high thermal conductivity and good adhesion, we tried to use AlN whisker developed by Nagoya university(2) to orient Z-direction. One volume percent of the AlN whisker improved the thermal conductivity drastically (3). Furthermore, we focused on reducing an interfacial heat resistance between high thermal conductive sheet composed of resin and heat conductive filler and metal such as Cu or Al. The interfacial heat resistance was determined by dispersion of high heat conductive filler and interfacial residual stress. The good dispersed sheet shows lower interfacial resistance than poor dispersed sheet, The interfacial residual stress causes an poor contact to metal to make void in the interface. To consider the effect of those facts, we successfully developed the high thermal conductive sheet with extremely low interfacial resistance. Bulk heat conductivity of the sheet is higher than 13W/mK. The interface heat resistance is below 0,009W/C.