Publication: Study of deformation and crack propagation on component during reflow soldering process
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Date
2024-07-01
Authors
Srehari A/L Perbagaran
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Abstract
The study investigates the deformation processes and fracture propagation behaviour of Multilayered Ceramic Capacitors (MLCCs) during the reflow soldering process under controlled thermal cycling circumstances. MLCCs are essential components in modern electronic devices and their thermal stability is critical to overall device performance and endurance. The reflow soldering process which is a standard production procedure, exposes MLCCs to rapid temperature changes which can cause mechanical strains, deformation and possibly crack formation. The objective of this research is to identify the effect of energy release rate (J-integral) and fracture toughness on crack during thermal cycling test to determine the critical point of failure. Besides, this study also intends to thoroughly examine how thermal cycling affects the structural integrity of MLCCs. The thermal cycles are intended to imitate the heat exposure and cooling rates that MLCCs experience during reflow soldering. From the results obtained, the crack propagation in the BaTiO3 layers was caused when the fracture toughness of the material was exceeded. At the 438th cycle, the fracture toughness of BaTiO3 was 57.1 MPa·mm1/2 which initiated the crack propagation. Moreover, the copper and copper – epoxy layers experienced plastic deformation when the stress was 144 MPa at 0.0009 mm strain which was greater than yield stress of copper. The copper layers experienced a peak stress of 340 MPa where the ultimate tensile strength was reached and fracture takes place. Besides, the highest J - integral obtained was 85.7 J/m2 after simulation for 750 thermal cycles was completed. The J-integral of copper was exceeded after 200 cycles when the J-integral value was higher than 7.6 J/m2.