Advancement in low melting solder deposition by pulsed Magnetron Sputter-PVD process for microsystemtechnology

In former investigations, the TLP systems Cu-Sn and Cu-In showed high potential for joining operations in microsystems. The benefit of these systems is the combination of the low melting elements to the eutectic alloy SnIn. For this low melting alloy, the substrate temperature as well as the target temperature is of interest. The substrate temperatures were set and controlled by an additional cooling unit which was integrated into the sputtering facility. The target temperature is minimized by use of a pulsed power supply for deposition. The effects of different pulse rates and substrate temperatures to the microstructure and the soldering suitability of the TLP solder systems were investigated by scanning electron microscopy (SEM), nanoindentation and soldering tests.