Predicting fracture of solder joints with different constraint factors

Abstract

Double cantilever beam (DCB) specimens of 2.5‐mm‐long SAC305 solder joints were prepared with thickness of copper adherends varying from 8 to 21 mm each. The specimens were tested under mode I loading conditions (ie, pure opening mode with no shear component of loading) with a strain rate of 0.03 second−1. The measured fracture load was used to calculate the critical strain energy release rate for crack initiation, Jci, in each case. Fracture behaviour showed a significant dependence on the adherend thickness; the Jci and plastic deformation of the solder at crack initiation decreased significantly with increase in adherend thickness. This behaviour was attributed to changes in stress distribution along the solder layer when the adherend thickness was varied. The capability of Jci as a property was then assessed to predict the fracture load of solder joints in specimens with different constraint levels caused by variations in adherend thicknesses. In light of the results obtained, a cohesive zone model (CZM) was developed to predict the fracture load of solder joints as a function of adherend thickness. Finally, a CZM with a single set of parameters was established to predict the fracture loads for all the cases. It was concluded that CZM was a better methodology to account for changes in degree of joint constraint imposed by bonding adherends.

Bondline thickness effect on fracture and cohesive zone model of sintered nano silver adhesive joints under end notched flexure tests

“…According to previous studies, 48,49,55–57 many factors could affect the solutions of reverse analysis, for example, maximum tangential stress, fracture energy, viscosity coefficient, and initial tangential stiffness. In order to study the effects of CZM parameters and CZM shape on the load versus displacement curves, those factors are investigated.…”

Application of data mining techniques for assessment of fracture load and energy in double cantilever beam solder joints

“…The soldering process done at a constant temperature of 220 ℃. Flux-cored Sn3.0Ag0.5Cu (SAC305) melting temperature occurs at this temperature [14]. For controlling the soldering length region, Kapton tape was used between two spaces that must be soldered.…”

“…Increasing adherend thickness, which reduces the plastic zone area in DCB solder joints, caused a sharp increase in the sample's fracture load tested at mode I crack propagation. Critical strain energy release rate (𝐽 ) has also experienced a 70% reduction by changing adherend thickness from its minimum value to maximum [14]. Karimi and Nourani [15], prepared single lap shear (SLS) samples and evaluated the effect of geometrical factors like adherend thickness and solder length on fracture load and energy at the strain rate of 0.01 𝑠 .…”

Deep neural network aided cohesive zone parameter identifications through die shear test in electronic packaging

“…Based on the fracture energy of the simplified shear slip model, the joints' failure load and shear strength were predicted by the CZM theory. However, CZM parameters will affect the determination of the traction separation rule of bonded joints, which is of great significance for reliability evaluation 31–33 …”

“…However, CZM parameters will affect the determination of the traction separation rule of bonded joints, which is of great significance for reliability evaluation. [31][32][33] Recently, machine learning (ML) methods have been developed to evaluate mechanical properties from mechanical test data [34][35][36] and predict mechanical parameters from mechanical test data. [37][38][39] In many studies, the combination of ML methods and CZM methods has shown great potential to effectively determine the CZM traction separation law or fracture energy of different materials.…”