다양한 유무연 도금 리드프레임에 적용된 Sn-8Zn-3Bi 솔더접합부의 열충격 신뢰성 평가

Abstract

The pull strength and fracture mechanism were investigated to evaluate the reliability and compatibility of Sn-8Zn-3Bi joints, the solder paste on lead and lead-free plating under thermal shock conditions. At the Sn-8Zn-3Bi solder joint, no crack initiation was observed during thermal shock test. After 1000 cycles, the strength of the solder joint decreased not sharply but reduced gradually compared with initial conditions. The decrement of strength was affected by g-Cu5Zn8 IMC growth which caused the IMC fracture on the fracture surface and a change in fracture mode and initial crack point. Clearly, the Sn8Zn-3Bi solder shows good reliability properties and compatibility with lead-free plated Cu LF under thermal shock temperatures between 248K and 423K.