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

fYear

2005

fDate

May 31 2005-June 3 2005

Firstpage

1210

Lastpage

1214

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;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronic Components and Technology Conference, 2005. Proceedings. 55th

Conference_Location

Lake Buena Vista, FL

ISSN

0569-5503

Print_ISBN

0-7803-8907-7

Type

conf

DOI

10.1109/ECTC.2005.1441424

Filename

1441424