Bending Strength of Solder Joints as a Function of Joint Length
Authors: Saeed Akbari, Amir Nourani, Jan K. Spelt Company: University of Toronto Date Published: 9/27/2015
Abstract: The effect of the joint length on the fracture of coppersolder-copper joints were investigated using doublecantilever-beam (DCB) specimens of various joint lengths. It was found that for solder joints shorter than a certain characteristic length the strength increased with increasing joint length. This characteristic length was found numerically using a finite element model to plot the maximum peel stress of the solder joint versus the joint length. The length at which the plot reaches a plateau was considered as the characteristic length. Characteristic lengths obtained from experiment and finite element analysis were in close agreement, indicating the validity of the numerical method. The practical importance of the characteristic length is that solder joints longer than the characteristic length have a maximum peel stress that remains unchanged with joint length, causing the joint strength to become independent of the joint length. In other words, the use of joints longer than the characteristic length provides no additional strength to the joint.
SAC solder, copper, joint length, peel stress, finite element analysis