Thermal contact resistance of cured gel polymeric thermal interface material

This paper reports the experimental results on the contact resistance of curable polymer gel thermal interface materials (TIM\´s) that have different mechanical properties due to difference in the rheology of the polymers. A semi-analytical model for the prediction of the thermal contact resistance of cured gel TIM\´s is also introduced in this paper. A novel method of finding the transition from grease type behavior to gel type behavior, which is very important for post reliability stress performance, based on G\´(storage shear modulus) and G"(loss shear modulus) measurements is reported. Further, Post thermal cycling thermal resistance degradation rate of gel TIM\´s are related to the ratio of G and G". Finally, design guidelines for gel TIM\´s for use in flip-chip packages comprising heat spreaders are proposed.