Study of Die Attachment on DBC Substrate

The paper describes the results of investigations concerning the behaviour and joint quality of various die attachment materials on DBC (Direct Bonded Copper) Al2O3 based substrates. A comparative study of influence of various material on joint quality was realized. Experimental samples were reflowed in a vacuum reflow oven, and in a vapour phase soldering (VPS) chamber. For the first time were applied new developed solder materials (Sn96.5Ag3.5 and Sn95.9Cu3In1Ag0.1 alloys) in the form of thin ribbons. The new metals and alloys were prepared by the rapid solidification technique - melt spinning at a cooling rate of 10(6) degrees C/s. First measurements show that the new materials meet high requirements on joints properties: better thermal conductivity and mechanical strengths, less voids and better thermo-mechanical reliability. The thin ribbons based on the melt spinning (rapidly cooled) materials are a promising candidate for use in the die attachment in power electronics.