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We examine the impact of the presence of a W plug on electromigration-induced voiding of the Al alloy layer of contacts to silicon. By comparing conventional Al alloy and W-plug contacts we show that the presence of the plug does not significantly improve the intrinsic susceptibility of contacts to Al voiding despite the elimination of the Al step coverage problem. Both the conventional Al alloy and W-plug contacts degrade by drift of the Al layer with a velocity that is not influenced by the contact structure. The sheet resistance of the underlayer material of multilayer conductors plays an important role in influencing failure times since it determines the rate of resistance increase due to electromigration.

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 7 Mg 0.6 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 highreliability, high-performance power module packaging.

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