Study on Reliability of Lead-Free IC Solder

• Main Authors: Kun – Sheng Ke, 柯坤昇
• Other Authors: Maw - Shang Lee
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/45237853002255336050

碩士 === 國立高雄應用科技大學 === 電子工程系 === 98 === The traditional solders of 63wt%Sn-37wt%Pb(63Sn37Pb) which contains a high level of Pb, were widely applied on Surface Mounting Technology . Howerver, many reports has been demonstrated that many electronic products which contained Lead solders may causes the problem of the environmental pollution , thus the Lead-Free solders were rapidly developed in recent years. In this paper , the different reliability of the 96.5wt%Sn-3.0wt%Ag -0.5wt%Cu four lead-free solder and 63wt%Sn-37wt%Pb solder were investigated . The surfaces of the various solders were measured by Scanning Electron Microscopy (SEM). The experimental results show that the capacity creep resistance of two lead-free solder Sn-Ag-Cu-Bi and Sn-Ag-Sb were significantly better than 60Sn40Pb solder, the creep rate is much smaller than 60Sn40Pb solder, and the creep variable life of fracture is greatly enhanced, particularly, the expectancy of Sn-Ag-Sb solder creep longest life. At the same time, The prediction of fatigue life for the solder joints of flip-chip plastic ball grid array packages under thermal shock tests was investigated in the present study. Finite element method was employed to simulate the deformation and stress/strain behavior of the packages. The stress/strain behavior of the flip chip-type plastic ball grid array package under the thermal shock test was studied by the finite element analysis and evaluate the fatigue life of the solder ball by the prediction formula of fatigue life. The simulation of Double Power Law Model, Hyperbolic Sine Law Model or Norton's Model was adopted . Through analysis, lead-free solder greatly improved the reliability of the solder joints, thermal fatigue life is more than four times the SnPb solder joints in the same circumstances.