Finite Element Simulation of Fracture Behavior of BGA Structure Solder Interconnects
The influences of the standoff height (h), contact angle (θ), pad size and loading rate on shear fracture behavior of BGA structure Cu/Sn-3.0Ag-0.5Cu/Cu joints were investigated by finite element (FE) method. The simulation results show that the maximum Von Mises stress zones locate on the edge of the solder near the intermetallic compound (IMC) layer in the BGA joint under shear stress, the cracks are more prone to initiate in the zones and this has been proved by the experimental observation. The standoff height and contact angle have slight influence on the value of the maximum Von Mises stress, while significantly affecting the size and location of the maximum Von Mises zones. Contrast with the standoff height and contact angle, the maximum Von Mises stress increases with the increase of the loading rate. Moreover, the simulation results show that cracks may more easily propagate along the IMC layer with decreasing h and θ, according to the criterion of maximum energy release rate. Furthermore, the crack tip stress intensity factors (SIFs) were calculated to estimate the fracture mode. It has been shown that SIFs are significantly influenced by the standoff height while being slightly affected by the contact angle and loading rate, and KI is always higher than KII regardless of the standoff height and contact angle of BGA solder joints. This may mean that for BGA joints subjected to shear stress the fracture or failure of BGA joints may dominantly occur by mode I (i.e., opening mode).
Qin Hong-Bo li Bin Li Xun-Ping Zhang Xin-Ping
School of Materials Science and Engineering, South China University of Technology
国际会议
上海
英文
991-996
2011-08-08（万方平台首次上网日期，不代表论文的发表时间）