Impact of sintering conditions on solderability and wire bondability of thick-film metallizations for Silicon-Ceramic composite substrates

An innovative Silicon-Ceramic (SiCer) composite system enables the combination of Micro-Electro-Mechanical-Systems (MEMS) and Low Temperature Cofired Ceramic (LTCC) technology through a sintering process. The sintering procedure and the sintering temperature are crucial for subsequent processes such as advanced packaging and assembly technologies. Various sintering profiles with different temperatures and heating rates are investigated. The bond interfaces of the manufactured SiCer substrates are evaluated by ultrasonic microscopy. Assembly technologies such as soldering and gold wire bonding are used to evaluate the influence of sintering temperatures on each metallization. Destructive testing methods are carried out to analyze the adhesion, soldered components are sheared off and the wire bonds are pulled. An influence of the sintering temperature on the quality of the bond interface has been proven through this study. The quantity and quality at the SiCer bond interface has been significantly improved and an optimized sintering profile has been established for different metallizations intended for soldering and wire bonding applications.