Cooling chip on PCB by embedded active microchannel heat sink

The use of chips is inseparable from printed circuit board (PCB), therefore, it is an effective way to realize microchannel heat sink (MCHS) on PCB to actively cool chip. For improving the integration and cooling efficiency, and reducing the size, energy consumption and coolant consumption of cooling system for thermal management of chips on PCB, the principle and structure of cooling chip on PCB by embedded active microchannel heat sink (EAMCHS) are proposed. EAMCHS is formed by simultaneously integrating MCHS, diffuser/nozzle piezoelectric micropump (PMP) and piezoelectric microvalves with annular boundary on PCB. Chip to be cooled is mounted directly on MCHS. PMP and piezoelectric microvalves enable EAMCHS to drive and control coolant, respectively. The finite element simulation model and theoretical model of cooling chip on PCB by EAMCHS are established to simulate and analyze its heat transfer characteristics and flow characteristics. The manufacturing and assembly based on PCB process are studied and EAMCHS is manufactured. The size and weight of the assembled EAMCHS are small (about 6.5 cm3) and light (about 18.2 g), respectively. Utilizing high temperature co-fired ceramic (HTCC) to simulate chip heating, the working performances of cooling chip on PCB by EAMCHS are experimentally tested and analyzed on the constructed experimental setup. Research results show that EAMCHS can control the temperature of HTCC at 64.0 °C with heat flux of 50 W/cm2 through the flow rate of 30.11 mL/min of coolant. The established theoretical model can describe heat transfer characteristics and flow characteristics of cooling chip by EAMCHS, which will be conducive to its structural design and optimization. The proposed EAMCHS has low energy consumption, small size and light weight, and provides a novel principle, novel method and novel structure for thermal management of chips highly integrated on PCB.