Title :
Effect of Stress Relaxation on Board Level Reliability of Sn Based Pb-Free Solders
Author :
Yoon, S. ; Chen, Z. ; Osterman, M. ; Han, B. ; Dasgupta, A.
Author_Institution :
CALCE Electron. Products & Syst. Center, Maryland Univ., College Park, MD
fDate :
May 31 2005-June 3 2005
Abstract :
The thermal fatigue data of two Sn-based Pb-free solders (Sn95.4/Ag3.9/Cu0.7, Sn96.5/Ag3.5) are presented. The test vehicles (LCCC mounted on FR-4 PCB) are subjected to various thermal cycling conditions; a constant temperature excursion (T = 100degC) with different cyclic mean temperatures and dwell times. The results are compared with the results of Sn63/Pb37. The results show that the two Pb-free solders outperform the SnPb solder at the lower cyclic mean temperatures, while the SnPb solder has a longer fatigue life at the higher cyclic mean temperatures. Reliability of the Pb-free solders has much stronger dependence on the cyclic mean temperature. The results are analyzed systematically to investigate the effect of stress relaxation at the peak temperature on the fatigue life
Keywords :
copper alloys; mechanical testing; reliability; silver alloys; solders; stress relaxation; thermal stress cracking; tin alloys; 100 C; FR-4 PCB; Pb-free solders; SnAgCu; SnPb solder; board level reliability; constant temperature excursion; fatigue life; stress relaxation; thermal cycling conditions; thermal fatigue; Assembly; Ceramics; Fatigue; Lead; Soldering; Stress; Temperature distribution; Testing; Tin; Vehicles;
Conference_Titel :
Electronic Components and Technology Conference, 2005. Proceedings. 55th
Conference_Location :
Lake Buena Vista, FL
Print_ISBN :
0-7803-8907-7
DOI :
10.1109/ECTC.2005.1441424
