Design of a high reliability and low thermal resistance interface material for microelectronics

Thermal interface materials (TIMs) play a key role in the thermal management of microelectronic devices by providing a path of low thermal impedance between heat generating devices and heat dissipating components (heat spreader/sink). In addition, TIMs often provide mechanical coupling between the silicon device and the heat spreader/sink. During device operation, the adhesive joint between the heat generating device and heat spreader/sink is subjected to thermomechanical stresses due to differences in thermal expansion coefficients of the silicon device and the heat spreader material. The adhesive joint can consequently delaminate or debond from the mating surfaces causing a significant increase in thermal impedance across the thermal interface material. Hence, a TIM needs to offer improved thermal performance as well as enhanced reliability. In addition to these characteristics, several other requirements such as adhesion strength, response to different assembly parameters, and volatile content need to be considered and addressed during the development of a TIM. This paper discusses the development of such an interface material and a comprehensive performance evaluation of the new TIM.