High-reliability, high-melting, lead-free, mixed solder paste System-BiAgXⓇ.

ABSTRACT

BiAgX®, a mixed solder powder paste composed of a primary high-melting solder powder and an additive low-melting solder powder, exhibited a melting temperature above 260 °C and was comparable to, or even better than, the reliability of high-lead solders. The additive solder is designed to react preferentially with various surface metallizations and form a controllable intermetallic layer. Inside the joints, sub-micron AgSn particles are dispersed surrounding Bi colonies, which constrain the dislocation movement, thus enhancing strength, ductility, and associated joint reliability.