An assessment of module cooling enhancement with thermoelectric coolers

The trend towards increasing heat flux at the chip and module level in computers is continuing. This trend coupled with the desire to increase performance by reducing chip operating temperatures presents a further challenge to thermal engineers. This paper will provide an assessment of the potential for module cooling enhancement with thermoelectric coolers. A brief background discussion of thermoelectric cooling is provided citing some of the early history of thermoelectrics as well as more recent developments from the literature. An example analyzing cooling enhancement of a multichip module package with a thermoelectric cooler is discussed. The analysis utilizes closed form equations incorporating both thermoelectric cooler parameters and package level thermal resistances to relate allowable module power to chip temperature. Comparisons are made of allowable module power with and without thermoelectric coolers based upon either air or water module level cooling. These results show that conventional thermoelectric coolers are inadequate to meet the requirements. Consideration is then given to improvements in allowable module power that might be obtained through increases in the thermoelectric figure of merit ZT or miniaturization of the thermoelectric elements.