Silver Sintering on Organic Substrates for the Embedding of Power Semiconductor Devices

The requirements for power electronic assemblies are continuously increasing and are mainly driven by costs, functionality, and reliability. A novel and promising approach is the embedding of power semiconductor devices into PCB-materials. Benefits are the reduction in size and volume of the system. The embedding of semiconductor devices provides a high degree of miniaturization. Also printed circuit board technology in combination with the use of established processes apparently has the potential for low-cost manufacturing. Further functional advantages are the possibility to place passive components and peripheral circuits close to the switching devices, enabling shorter commutating paths. In consequence, they are expected to produce smaller parasitic effects caused by the package, which results in higher possible frequencies and reduced conduction and switching losses. However, there is a significant challenge regarding package design, processing, and materials selection to make use of this potential even at high operating temperatures. To address only one aspect, generally used materials, like epoxy-glass-substrates (FR4) and solder alloys like PbSnAg or SAC are not suitable for temperatures above 150 °C. This work will introduce and evaluate a concept for double-side Ag-sintered semiconductor chips, which are embedded between two organic high-temperature PCBs. A proof-of-concept will be presented by setting up a 30 kW (600 V, 50 A) power package as a demonstrator.