Spatial Thermal Conductivity Variation of Particulate-Filled Thermal Interface Materials

Thermal interface materials (TIMs) are widely used in electronic devices owing to their ability to thermally bridge gaps at the interface between electronic devices and heat removal device. The design goal of TIMs is to minimize the thermal interface resistance during the device’s service lifetime. Previous reports from industry focus on the average thermal properties of TIMs. We explored how thermal properties of different polymeric TIMs vary spatially, using a setup with a spatial resolution as low as 10µm. This resolution enables quantification of spatial variability, which is important to preventing hot spots. We developed an understanding of how polymeric TIM properties change locally due to bond line thickness, applied pressure, and thermal cycling conditions. Complementary characterizations of thermal interface materials made via electron microscopy, electron dispersive x-ray spectroscopy, x-ray imaging, differential scanning calorimetry, and mechanical testing will be shared. TIMs thermal properties measured with frequency domain thermoreflectance, and steady-state techniques for different bond line thicknesses will be related to these non-thermal characterizations.