Tilting Behavior and Phase Formation of Sn-Cu Composite Solder for Large Area Baseplate Solder Joints

This work is part of a publicly funded project called ReffMaL (resource efficient material solutions for power electronics) which aims to reduce solder thickness significantly, while maintaining reliability. In this paper we present findings of the investigation of two types of composite solder materials, to determine the more favorable one regarding tilt, phase formation and reliability. Both preform types consist of the same amount of Sn and Cu but in different three-dimensional arrangements. The layouts of these composite materials are designed in order to prevent the tilt of substrates during soldering process. The presented layouts consist of a high amount of pure copper in order to replace the more expensive metals Sn and Ag and simultaneously providing a lower thermal resistance of the joint compared with its monolithic solder materials opponents.