Investigation of Pressureless Sintered Interconnections on Plasma Based Additive Copper Metallization for 3-Dimentional Ceramic Substrates for Surface Acoustic Wave Sensors in High Temperature Applications

摘要

Spatial circuit boards allow the integration of third dimension which results in new design freedom and in high potentials for miniaturization as well as rationalization by integration of electronics. The three-dimensional design of electronic devices can save material and cost. At high temperatures thermoplastics and thermosets, which are the standard materials of 3D-MID, reach the limits of their range of application. Ceramic substrates are a state-of-the-art material for power electronics and high-power-LED applications, mainly due to their stability in thermally demanding conditions. The focus of this publication is the evaluation of an additively manufactured surface on alumina substrates realized by a plasma-based coating method in interaction with a die attach layer using pressure-less silver sinter technology. Therefore, the deposition of copper on alumina substrates using several particle temperatures as well as additional heat treatment processes with different atmospheres were evaluated. The resulting surfaces were characterized and compared to a chemically treated surface. The formation silver sintered interconnections on the additively manufactures copper layers was investigated by destructive and non-destructive methods. Finally, the findings were transferred and used for attaching a surface acoustic wave sensor on additively metallized ceramic substrates. This publication compares the achieved results with direct copper bonded substrates (DCB) used for power electronics and describes the challenges of forming pressure-less silver sinter joints on a plasma-based copper layer for later adaption on spatial copper metallized Al2O3 substrates.