Hot spot aware microchannel cooling add-on for microelectronic chips in mobile devices

This work proposes an experimental microchannel solution to cool microelectronic chips with hot spots, using a non-intrusive technique. In microelectronics, approaches such as die thinning induces acute stress on cooling because it increases the hotspot phenomena and reduces chip bulk thickness aimed for microchannels. In mobile devices, the heat must be removed using limited pumping power and cooling space. Microchannels etched in the backside of the chip, usually considered as an efficient cooling solution, are impracticable on highly thinned chips. This work experimentally investigates the cooling performance of a non-invasive and hot spot aware microchannel die that is in direct fluidic contact with the backside of the chip. It also proposes a confinement-wise metric. A thermal resistance of 2.8 °C/W is achieved at heat flux of 1185 W/cm2 per heat source, for a total dissipated power of 20 W and a maximum allowed temperature rise of 55 °C. Such performance is obtained with only 19.2 kPa of pressure drop and 9.4 ml/min of flow rate, making a hydraulic power of only 3 mW, representing a coefficient of performance of 6500. Therefore, backside cooling appears as a compact and low consumption solution for highly confined heat on chips for mobile applications.