A cost-driven analysis of thermal performance in power modules

This paper offers an in-depth overview of the trade-off between thermal performance and assembly cost in state-of-the-art power modules (PMs). Since the development of the PM technological process is still in its infancy, PMs are typically designed and prototyped in order to evaluate their electrical/thermal characteristics. The numerical investigation conducted here aims to analyze the impact of design choices (e.g., assembly materials and dimensions, cooling system efficiency) on the thermal resistance (RTH, [K/W]), thermal time constant (τ, [s]), and overall cost (PMcost, [$]) of semiconductor devices integrated in both single- and double-sided cooled PMs, without any need for prototyping stages. The influence of the thicknesses of the copper and ceramic layers is explored, since they play a relevant role in defining the thermal ratings, as well as the electrical and mechanical characteristics, of the assemblies. The benefits deriving from thicker layers are then weighed against the cost of materials, and figures of merit are defined to evaluate the trade-offs between cost and thermal behavior. The impact of two cooling solutions—passive heatsink and forced liquid—is also taken into account.