Performance of Integrated Thin-film Thermoelectrics in cooling “hot-spots” on Microprocessors – Experimental setup and Results

Abstract

ABSTRACTThe improving performance of microprocessors is increasing the Thermal Design Power [TDP] and cause localized power densities commonly referred to as “Hot-spots”, which reach in excess of 200 W/cm2. The focus of this work is to present Thin-film Superlattice Thermoelectric materials [TFST] as a solution for microprocessor die hot spot cooling. TFST have measured ZT values of ∼2 at 300K, response times of the order of 15μs and potential to pump heat flux of several hundred Watts/cm2. TFST devices appear suitable for managing the junction temperatures at such hot spots such that the recommended maximum operational temperature, Tjmax, is not exceeded. This promotes stable processor performance and increased reliability. To test this theory, hot spots were identified on the microprocessor die by infrared (IR) imaging during operation and a suitable TFST module was mounted onto the processor. Thermal transients at the hot spot show that active heat pumping and spreading by TFST significantly reduces the constraints on the thermal design. This investigation suggests that in the future, with the transition of Superlattice material performance into higher module ZT values; these hot spots may be effectively removed.