Sintering of Ag80-Al20 nanoalloy for high temperature die attach applications on silicon carbide-based power devices: The effects of ramp rate and dwell time

Abstract

The effects of sintering on Ag₈₀-Al₂₀ nanopaste for use as a high temperature die attach material was studied. The sintering profile was fixed at 380°C, while the ramp rates and dwell times were varied at 5 to 10°C/min and 10 to 50 mins, respectively. It was shown statistically that dwell time had a more profound effect on the physical outcome of the sintered material. The post-sintered Ag₈₀-Al₂₀ die attach material was analyzed for its electrical, thermal and mechanical properties. It demonstrated an electrical and thermal conductivity of 1.01 × 10^-5 (ohm-cm)^-1 and 123 W/m-K, respectively. Its melting point was determined at 518 ± 1°C, with an operational temperature of approximately 400°C. The low modulus of elasticity, E, at 9.8 GPa, matched the drop in values of hardness and stiffness as well, due to the formation of pores within the material. This altered the attributes of the die attach material. Its low CTE value at 7.74 × 10^-6/°C is close to SiC which make it a suitable candidate for high temperature die attach applications.