Comparative analysis of novel thermal interface containing nano additives

Nowadays a passive cooling based on efficient reliable thermal interfaces begins to play a dominant role in modern consumer electronics. The devices become smaller, thinner and more powerful while semiconductors become the source of higher flux heat density. In order to reduce thermal resistance between a semiconductor junction and a heat spreader, semiconductor structures remain unpackaged i.e. flip-chip structures. In the case of such solution semiconductor dies have a direct contact with a heat spreader (i.e. surface of metal radiators). In order to decrease thermal resistance of the contact some Thermal Interface Material (TIM) is usually applied. A TIM should form a low thermal resistance contact and ensure a long term stable interconnection in respect of its thermo-mechanical properties. Within the frame of the study three novel sintered nano silver pastes and one commercially available thermally conductive adhesive were compared and evaluated as potential TIMs. Formed thermal interfaces between power transistors and copper substrates were assessed in respect of their structure (X-Ray computed tomography) and heat dissipation performance (IR thermography).