Sn-37Pbはんだのクリープ疲労き裂進展評価

抄録

The fatigue life estimation of micro solder joints is one of the most critical technologies for the reliable IC packages. In recent years, it is considered that the development of estimation methods for the crack propagation based on the fracture mechanics approach is important to the life prediction. In this study, the crack propagation behavior of Sn-37 Pb solder was investigated. Fatigue tests using CT specimens were carried out under 0.1 Hz, 0.01 Hz and 0.001 Hz. As a result, the crack propagation rate was correlated well with the fatigue J-integral range independently of the frequency. On the other hand, the fracture surfaces for all conditions were intergranular creep types. The creep-fatigue tests under stress waveforms with tensile hold (cp-type) and with tensile and compressive hold (cc-type) were carried out at room temperature using CCT specimens. The relationship between the crack propagation rate and the creep J-integral range was obtained. The crack propagation rate under the cc-type condition was lower than the one under the cp-type condition for the same value of creep J-integral range.