Reliability of Cu nanoparticle joint for high temperature power electronics
Power cycle reliability of Cu nanoparticle joint has been studied for high temperature operation of power devices. Al2O3 heater chips and Cu65wt%Mo baseplates were joined by Cu nanoparticles and Sn0.7Cu and power cycle tests of 65/200C and 65/250C were carried out on the joints. The Cu nanoparticles were prepared by reducing Cu carbonate in ethylene glycol with dodecanoic acid+dodecyl amine (C12) and decanoic acid and decyl amine (C10) as capping agents. A power cycle test of 65/200C did not inflict severe damage on the Cu nanoparticle joints so that there were not many cracks formed after 3000 cycles. Vertical cracks were formed in the C12 Cu nanoparticle joint after 3000 cycles of 65/250C test, however the maximum temperature during the power cycle test did not change at all because vertical cracks did not have an effect on preventing heat flow. On the contrary, lateral cracks were completely formed in the Sn0.7Cu soldered joint after 200 cycles of 65/200C test and in the C10 Cu nanoparticle joint after 360 cycles of 65/250C test. In these experiments, the maximum temperatures were rapidly increased because heat conduction was prevented across the formed lateral cracks.
cu nanoparticle joint power cycle sintering high-temperature reliability