Package-Level Microjet-Based Hotspot Cooling Solution for Microelectronic Devices

A package-level hotspot cooling solution using Si hybrid heat sink and diamond heat spreader has been developed. The hybrid heat sink combines the merits of both microchannel flow and microjet array impingement, and can enable high spatially average heat transfer coefficient of 18.9 × 104 W/m² K with low pumping power of 0.17 W. The liquid jet is designed to directly impinge on the surface of the diamond heat spreader. The eight hotspot heaters, each of size 450 × 300 μm², were fabricated on the Si thermal test chip. The solid-fluid coupling simulation has been conducted using heaters model for microfluid cooling capability investigation. A gates model in conjunction with the heaters model is used to predict the thermal performance of the GaN transistors with the developed cooling solution. Hotspot cooling capability as high as 10 kW/cm² was demonstrated and validated. The heating power density of 3.9 W/mm can be dissipated in GaN device, while maintaining the peak gate temperature under 200°C.