Evaluation and process optimization of silver sintering using pressure-less pastes for power module assembly

In today’s landscape, even a perfect solder joint may no longer suffice. Conventional Sn-Ag and Sn-Ag-Cu alloys are unsuitable for high-temperature applications due to their low melting points, while high-lead solder is generally avoided due to environmental concerns. Contrarily, silver and copper sintering materials offer higher operational temperatures thanks to their elevated melting points and higher reliability in a stressful environment. They can be processed at temperatures comparable to or lower than those of solder materials, thereby reducing thermal stress during manufacturing and eliminating the risk of damaging sensitive components. Additionally, they show excellent thermal and electrical conductivities as well as favorable thermomechanical properties, making them ideal for modern applications. This dissertation aims to evaluate and optimize four different pressure-less silver sinter pastes for power module assembly, demonstrating their reliability as assessed through temperature cycling tests. The research focuses on identifying the optimal parameters to achieve the most robust and reliable joints possible. Hence, pressure-less silver sintering is proposed as a potential solution and alternative to conventional solder joints.