High-speed formation of a near-full-density bondline in sinter-bonding below 250°C using 2 µm Cu particles coated with Ag

Abstract

High-speed attachment of dies on an Ag finish was demonstrated through pressure-assisted sinter-bonding at temperatures <250°C using 2 μm Cu particles coated with Ag, to achieve a high-temperature sustainable bondline. The Ag shells were dewetted by instability at the Ag layer/Cu core interface during heating, which initiated the sinter-bonding. Consequently, in the case where Ag coating content was 20 wt-%, sufficient shear strengths of 24.6 and 34.1 MPa were measured even after an extremely short bonding time of just 1 min, at 220 and 250°C, respectively. When Ag coating content was increased to 40 wt-%, high shear strengths of 29.5–30.5 and 35.6–36.3 MPa were measured after ultra-rapid bonding for 0.5–1 min at 220 and 250°C, respectively. Furthermore, near-full-density bondlines could be achieved through a nano-volcanic eruption behaviour after a relatively short bonding time of 5 min at both 220 and 250°C.