Enhanced Boiling Heat Transfer from Silicon Chips with Micro-Pin Fins Immersed in FC-72

Abstract

Experiments were conducted to study the effect of the size of micro-pin fin on boiling heat transfer from a silicon chip immersed in a pool of degassed or gas-dissolved FC-72. Four kinds of micro-pin fins with dimensions of 10 × 60, 20 × 60, 30 × 60, and 50 × 60 μm2 (thickness × height) were fabricated on the surface of a square silicon chip with dimensions of 10 × 10 × 0.5 mm3 using the dry etching technique. Experiments were conducted at liquid subcooling of 0, 3, 25, and 45 K under atmospheric conditions. The results were compared with those for a smooth chip and previously developed enhanced surfaces. The micro-pin-finned chips showed a considerable heat transfer enhancement over the smooth chip in the nucleate boiling region. The boiling curve showed a steep increase in heat flux with increasing wall superheat. For the micro-pin-finned chips, the critical heat flux was 1.9–2.3 times as large as for the smooth chip, and the wall temperature at the critical heat flux point was lower than the upper limit for the reliable operation of large-scale integration (LSI) chips (= 85 °C). While the wall superheat at boiling incipience was strongly dependent on the dissolved gas content, it was little affected by the liquid subcooling.