Frequency dependent S-N curves for predicting drop impact robustness of Pb-free solder interconnects

Author

Zhao, X.J. ; Caers, J.F.J.M. ; Wong, E.H. ; Seah, S.K.W. ; Driel, W.D.v. ; Owen, N. ; Lai, Yi-Shao

Author_Institution

Philips Appl. Technol., Eindhoven

fYear

2009

fDate

26-29 May 2009

Firstpage

93

Lastpage

99

Abstract

In this paper, a series of PCB strain-to-fatigue life characteristics were generated at a constant bending frequency of 100Hz for different material combinations: eutectic SnPb solder, SAC101 solder, and In/Ni-doped SAC101 solder, assembled on PCB with OSP and ENIG finish respectively. As expected, SAC101 solder exhibits similar performance as eutectic SnPb solder, and solder joints on OSP finish show better performance than solder joints on ENIG. The effect of bending frequency in the range of 30Hz to 150Hz was investigated and the fatigue life was found to decrease with increasing bending frequency. Failure analysis has shown that failures tend to become more brittle with increasing cyclic bending frequency. The PCB strain-to-fatigue life characteristics were converted to peeling stress in the solder joint -to-fatigue life (S-N) using 3D finite element modeling supported by strain rate dependent stress-strain properties of the solder alloy. The S-N characteristics so obtained were found to be independent of the bending frequency.

Keywords

adhesion; bending; brittleness; failure analysis; fatigue; integrated circuit interconnections; printed circuits; solders; stress-strain relations; 3D finite element modeling; PCB strain-to-fatigue life; bending frequency; eutectic solder; failure analysis; frequency 30 Hz to 150 Hz; peeling stress; solder alloy; solder interconnects; solder joints; strain rate dependent stress-strain properties; Assembly; Capacitive sensors; Character generation; Failure analysis; Fatigue; Finite element methods; Frequency dependence; Robustness; Soldering; Stress;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronic Components and Technology Conference, 2009. ECTC 2009. 59th

Conference_Location

San Diego, CA

ISSN

0569-5503

Print_ISBN

978-1-4244-4475-5

Electronic_ISBN

0569-5503

Type

conf

DOI

10.1109/ECTC.2009.5074002

Filename

5074002