Paper Title:
Bending Fatigue Characteristic of Sn-3.5Ag Solder Bump on Ni-UBM
  Abstract

Bending fatigue behavior of eutectic Sn-3.5Ag solder bump bonded on FR4-PCB was characterized by experimental and finite element method (FEM). To investigate an effect of stress state on bump failure, which had not been weighed in conventional Coffin-Manson model of Nf=K ⋅εp -1~-2, ‘fatigue frequency variable’ and ‘bump viscoplasticity’ were included in analysis procedure. As experimental results, with increasing fatigue cycles from 3,000 to 10,000, bond strength decreased from 98.9% to 76.5%, and from 97.5% to 67.1% at the fatigue frequencies of 2.5Hz and 5.0Hz, respectively. Stress state could be critical components to determine fatigue life, which should be combined in Coffin-Manson criteria. FEM calculation showed that higher bending frequency led to higher normal stress development at the solder and IMC interface, but smaller plastic strain in bump. However, bending fatigue experiment revealed discrepant results from that of Coffin-Manson criteria. Higher bending frequency, which was predicted to give rise to smaller εp at solder, showed dramatic bond deterioration of solder bump on UBM (under bump metallurgy). This was confirmed experimentally through SEM (scanning electron microscopy) observation as cracks were found at the solder bump and UBM interfacial IMC, Ni3Sn4, in case of the higher bending frequency.

  Info
Periodical
Materials Science Forum (Volumes 580-582)
Edited by
Changhee Lee, Jong-Bong Lee, Dong-Hwan Park and Suck-Joo Na
Pages
177-182
DOI
10.4028/www.scientific.net/MSF.580-582.177
Citation
K.I. Kang, J.P. Jung, W. H. Bang, J.H. Park, K. H. Oh, "Bending Fatigue Characteristic of Sn-3.5Ag Solder Bump on Ni-UBM", Materials Science Forum, Vols. 580-582, pp. 177-182, 2008
Online since
June 2008
Export
Price
$32.00
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: You Tang Li, Ping Ma, Chang Feng Yan, Fu Yuan Lang
Abstract:Safety designs and fracture designs are the two important fields of crack theory. The fracture problems of middle carbon steel under...
1153
Authors: Ryosuke Matsui, Hisaaki Tobushi, Yoshiyasu Makino
Abstract:In this study, we performed the bending fatigue test and investigated the influence of strain ratio on fatigue life in TiNi shape memory...
1193
Authors: Dal Woo Jung, Nak Sam Choi
Abstract:Fatigue fracture behavior of a hybrid joint part for the tilting car body was evaluated in comparison to the case of static fracture. The...
2860
Authors: Qiang Shen, Chang Lian Chen, Fei Chen, Qi Wen Liu, Lian Meng Zhang
Abstract:Porous calcia stabilized zirconia ceramics (CSZC) with closed pores were presurelessly sintered by adding different contents of zirconia...
435
Authors: Pei Sheng Liu, Long Long Yang, Jin Xin Hang, Ying Lu
Chapter 1: Materials and Technologies in the Scale of Micro and Nano
Abstract:Electro-migration has become a critical reliability issue for high density solder joints in flip chip technology, especially for current...
319