Development and Testing of a Planar, Silicon Mini-Capillary Pumped Loop

Abstract

A planar, silicon mini capillary pumped loop (CPL) was designed, built, and tested using recent MEMS technology to provide integral cooling and temperature control for electronics. This design featured three silicon fusion bonded wafers incorporating an evaporator, condenser, liquid line and vapor line, all of which were dry plasma etched. Grooves were etched in the condenser and evaporator to provide passive capillary pumping. An insulated gate bipolar transistor (IGBT) was bonded to the evaporator region of the CPL and an external reservoir attached to a port hole in the finished device. The CPL was then filled with a working fluid of water. A calorimeter was attached via epoxy above the condenser to control condenser temperature and monitor heat removal. The mini-CPL was operated with an input heat load ranging from 3 to 10 W resulting in the junction temperature of the IGBT being reduced approximately 15 C from that of a solid SI substrate. This mini-CPL also performed as a thermal diode, turning on or off depending on the reservoir temperature. Work is in progress to understand the dynamics observed in the CPL as well as increase the CPL’s performance to its full potential.