Current and future miniature refrigeration cooling technologies for high power microelectronics

Utilizing refrigeration may provide the only means by which future high-per formance electronic chips can be maintained below predicted maximum tempera ture limits. Widespread application of refrigeration in electronic packagin g will remain limited, until the refrigerators can be made sufficiently sma ll so that they can be easily incorporated within the packaging A review of existing microscale and mesoscale refrigeration systems revealed that only thermoelectric coolers (TEC's) are now commercially available in small siz es. However, existing TEC's, are limited by their maximum cooling power and low efficiencies. A simple model was constructed to analyze the performanc e of both existing and predicted future TEC's, in an electronic packaging e nvironment. Comparison with the cooling provided by an existing high-perfor mance fan shows that they are most effective for heat loads less than appro ximately 100 W, but that for higher heat loads, fan air cooling actually yi elds a lower junction temperature. If the efficiency of future TEC's, as ch aracterized by ZT(room), where Z is the figure of merit and T-room is room temperature, can be increased from the present value of similar to 0.8 to 2 or even 3, the performance of the TEC improves dramatically, thus making t hem competitive far many electronic applications. Finally, one unanticipate d result of the model was the realization that the thermal resistance betwe en the refrigerator and the chip is not as critical as the thermal resistan ce between the refrigerator and the ambient air.