Study of Critical Vias Design Parameters for Power Electronics Thermal Management

With the advent of wide band gap semiconductor devices like SiC based MOSFETs/Diodes, there is a growing demand for utilizing electrical power instead of the conventional fuel-based power generation in both automotive and aerospace industry. In automotive/aerospace industry the focus on electrification has resulted in a need for sub-systems like inverters, power distribution units, motor controllers, DC-DC converters that actively utilize SiC based power electronics devices. To address the growing power density requirements for electronics in next generation product families, more efficient & reliable thermal management solution plays a critical role. The effective thermal management of the power electronics is also critical aspect to ensure overall system reliability. The conventional thermal management system (TMS) optimization targets heat sink/ cold plate design parameters like fin spacing, thickness, height etc. or sizing of the required cooling pump/fan. This paper focuses on reducing the thermal resistance offered by printed circuit boards (PCBs) with the use of Via-in-pad technology embedded inside the PCBs for power electronics thermal management. In this work Computational Fluid Dynamics (CFD) modeling has been extensively used to study different Vias arrangements and arrive at an optimum design. The critical parameters associated with the design of thermal Vias like spacing, diameter, plating thickness and conductive fill have been studied and the optimized PCB design has been prototyped and tested to validate the analysis findings. The studies presented in this paper will help in optimizing the cooling architecture for power electronics assemblies used in automotive and aerospace industry that will enhance system reliability.