High resolution microstructural investigation of leadfree Aluminium-Germanium and Aluminum-Germanium-Copper alloys for high temperature silicon die attach

Due to the RoHS and WEEE legislative requirements the implementation of lead free solder material is of prior significance in electronic manufacturing. As a consequence, many efforts have been started in order to adapt the soldering technology as well as to provide adequate equipment and materials. While European RoHS regulations currently exempt high Pb solders used as component solders and die attaches for automotive and other high temperature applications, there is a strong drive to find Pb-free alternatives for these high temperature electronic applications, as well. The development of lead-free solder materials with improved reliability properties requires a detailed understanding of the microstructure and thermal behavior. Aluminium-Germanium and Aluminum-Germanium-Copper alloys are described in literature as possible alternative solder materials for high temperature silicon die attach. However, no micro structural or process properties are released. In this study, DSC measurements will be performed to analyze the melting point of the different alloys and the crystallization behaviour. High resolution micro structural analyses will be shown at Al-Ge and Al-Ge-Cu alloys in initial condition and after melting processes. Using Focussed Ion Beam techniques (FIB) and Scanning Electron Microscopy (SEM) the alloys will be analyzed in delivery condition and after defined temperatures. Additionally the wetting behaviour of the two alloys will be described for different surfaces. Summarized this study gives a comprehensive knowledge of microstructural phenomena for the specific Aluminium-Germanium and Aluminum-Germanium-Copper alloys.