Evaluation of Direct Printed Heat Sinks on Metallized Ceramic Substrate for High-Performance Power Modules

Abstract

In this article, we propose a new packaging technology enabling the development of a high-performance power module for harsh environments. This approach is based on the use of the selective laser melting (SLM) technique in order to directly print metal heat sinks on the backside of the metallized substrate. In order to explore the viability of this method, the assembled parts were evaluated thoroughly after the manufacturing process. Moreover, their robustness was assessed during aging under harsh conditions. Results show that the ultimate tensile strength and yield strength of the printed alloy are higher than the casted AlSi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> Mg <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.6</sub> counterpart. The interfaces between the printed alloy and the substrate Al metal layer do not show any weaknesses, and shear stress values are higher than 100 MPa. For all heat sink patterns, the substrate warpage is reduced during thermal cycling due to the Al alloy creeping, while the highly curved substrates show cracks in the ceramic after 400 cycles. Accordingly, direct printing of heat sink with patterns based on fins array reveals a promising path for high-reliability, high-performance power module packaging.