Air cooling of a microelectronic chip

A single-mask process is used to fabricate metal microchannels of 5–10 μm in width, 10–40 μm in height and millimeters in length, monolithically (i.e., no bonding) on the chip front side. Taking advantage of the small size and the diverging cross-section allowed for these microchannels, we explore the air cooling of a microelectronic chip, addressing the limitations of the liquid cooling with the well-known silicon bulk-etched microchannels. Upon the air flow, a distributed array of temperature sensors integrated on a heater chip reads a temperature drop (e.g., from 90 ◦C to 25–27 ◦C) and confirms an effective cooling. A thermal analysis further predicts a heat removal capacity of more than 35 W cm−2 by optimized microchannels with a pressure drop of 30 psi (207 kPa). The compatibility with IC fabrication and the use of air as the coolant makes the chip packaging and the system implementation of the reported approach simpler and economical for microelectronic chip cooling. (Some figures in this article are in colour only in the electronic version)