Simulation and Characterization of Si-based Microchannel for Module Level Cooling

Microwave modules have been increasingly complex and highly integrated, while power dissipation and signal gain increased accordingly. To satisfying this requirement, the third generation semiconductor high performance ICs, such as GaN chips, have been widely used in arrayed T/R unit and power amplifier modules, leading to sharply rise in power consumption and heat flux. Traditional cooling technologies such as natural convection and contact-type heat conduction cannot remove heat effectively, therefore, the forced highly efficient liquid cooling technique has been adopted. In this paper, three dimensional computational fluid dynamic (CFD) models are developed in ANSYS CFX to understand the flow resistance characteristics, heat dissipation capacity of different kind microfluidic structures (Two kinds of microfluidic structures had been designed and simulated, respectively, straight- through channel and variable cross-section channel), all simulated microfluidic structures have been manufactured by using deep silicon etching and Si-Si bonding. The GaN switch chip and power amplifier chip in this simulation are simplified to block heat generation with uniform heat source surface. In order to determine the flow state, turbulence and laminar flow effect have been taken into consideration respectively, which were verified by thermal characteristic. To verify the simulation results, power amplifier modules with different microfluidic structure integrated have been designed and assembled, the liquid cooling experimental setup have been built to characterize different kinds of microfluidic structures. The test results make a good agreement with our simulations, proving that the CFD modeling and simulation are reasonable.