Effective cooling of integrated circuits using liquid alloy electrowetting

Electrical modulation of surface tension is proposed for actuation and pumping of discrete droplets of liquid metals/alloys for active heat management of ICs and removal of hot spots on any solid surface. The proposed technique is based on two observations: (i) by using liquid metals or alloys at room temperature heat transfer rate of a cooling system can be enhanced significantly; (ii) electrowetting is an efficient, low power consumption, and low voltage actuation technique for pumping liquids at micro-scales. Preliminary calculations indicate that more than two orders of magnitude increase in heat transfer rate could be achieved by using liquid metals as compared to systems using water. Liquid velocities above 10 cm/s are observed with extremely low pumping power consumption and at low actuation voltage (∼2 V). It is expected that digitized electrowetting can offer a viable cooling strategy to achieve the most important objectives of electronic cooling; i.e. minimization of the maximum substrate temperature and reduction of the substrate temperature gradient and removing substrate hot spots.