Analysis of Phase Change Material for Use as Thermal Interface Material

Demands for thermal control in IC chips are more rigorous with increasing power dissipation in electronic devices. The thermal interface material forms an important passage for efficient heat transfer in the chip, and a study has been done to analyze the thermal performance of a particular type of polymeric thermal interface material, phase change material (PCM). A frequent benchmarking characteristic of a thermal interface material is thermal conductivity. As the thickness of the material being used in the real applications gets thinner (typically a few mils), bulk properties like thermal conductivity gives way to interfacial properties as important considerations. To this end, an instrument to suitably measure critical parameters, like the apparent and contact thermal resistance of the thermal interface material, is developed, using the ASTM D5470 as guidelines and modified to suit the semiconductor industry. The measured thermal resistance values obtained in this study allow the evaluation of effective, rather than bulk, thermal properties of the material. In addition, a brief theory of the thermal interface material is described and the properties of the PCM were investigated using the instrument. Other crucial properties that contribute to the efficiency of heat transfer were also analyzed. Characteristics like the bulk thermal conductivity, melting enthalpy, specific heat capacity, and contact resistance are employed in fundamental Equations to comprehend and predict the temperature profile of cooling heated entities.