Recently, the increasing performance of semiconductor devices has been accompanied by a simultaneous rise in the amount of heat they emit. When an electronic device is mounted on a metallic heat sink, a thermal interface material is required to handle the thermal energy emitted while simultaneously maintaining an acceptable level of electrical insulation. However, the thermal characteristics of thermal interface materials are strongly influenced by the manner in which they make contact with the
... heat sink. We proposed measuring the thermal characteristics of a thermal interface material placed on an aluminum plate that had been machine-milled to form precise grooves designed to simulate heat sink surface roughness, and called it a "non-flat plate". This plate had nine 1-mm-wide 0.3-mm-deep grooves situated 4 mm apart. When pressure is applied to the thermal interface material, the material penetrates into these grooves, thus increasing contact between the two materials and consequently decreasing thermal resistance. Then, by varying the groove shapes and applied pressure amounts, contact conditions can be precisely controlled. This allows complex thermal parameters to be measured with good repeatability.