Title :
Lead-free 95.5Sn-3.8Ag-0.7Cu solder joint reliability analysis for micro-BGA assembly
Author :
Pang, JohnH L. ; Low, Patrick T H ; Xiong, B.S.
Author_Institution :
Sch. of Mech. & Production Eng., Nanyang Technol. Univ., Singapore
Abstract :
A design-for-reliability methodology was applied to a micro-BGA assembly with lead-free, 95.5Sn-3.8Ag-0.7Cu solder joints. A rate dependent viscoplastic Anand model was curve fitted from a series of constant strain rate tensile test and creep test results. The material parameters for the viscoplastic Anand model for 95.5Sn-3.8Ag-0.7Cu solder was implemented in finite element analysis. Low cycle isothermal fatigue test was conducted over three frequencies of 1 Hz, 0.01 Hz and 0.001 Hz; three temperatures of 25°C, 75°C and 125°C; and four total strain range values of 2, 3.5, 5, and 7.5% respectively. A micro-BGA assembly with lead-free, 95.5Sn-3.8Ag-0.7Cu solder joints was subjected to (-55 to 125°C) thermal cycling test and the Weibull distribution was obtained. FEA modeling and simulation was employed to predict the fatigue life cycles of the micro-BGA package and compared to the MTTF life cycles.
Keywords :
Weibull distribution; ball grid arrays; copper alloys; creep testing; failure analysis; fatigue testing; finite element analysis; microassembling; reliability; silver alloys; solders; tensile testing; tin alloys; viscoplasticity; -55 to 125 degC; 0.001 Hz; 0.01 Hz; 1 Hz; MTTF life cycles; SnAgCu; Weibull distribution; creep test; fatigue life cycles; finite element analysis; isothermal fatigue test; microBGA assembly; microBGA package; solder joint reliability analysis; solder joints; strain range values; strain rate tensile test; thermal cycling test; viscoplastic Anand model; Assembly; Creep; Design methodology; Environmentally friendly manufacturing techniques; Fatigue; Lead; Predictive models; Soldering; Tensile strain; Testing;
Conference_Titel :
Thermal and Thermomechanical Phenomena in Electronic Systems, 2004. ITHERM '04. The Ninth Intersociety Conference on
Print_ISBN :
0-7803-8357-5
DOI :
10.1109/ITHERM.2004.1318270
