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This paper aims to study the interfacial delamination found in the boundary of the copper/copper-epoxy layers of a multi-layer ceramic capacitor.

The thermal reflow process of the capacitor assembly and the crack propagation from the initial micro voids presented in the boundary, and later manifested into delamination, were numerically simulated. Besides, the cross section of the capacitor assembly was inspected for delamination cracks and voids using a scanning electronic microscope.

Interfacial delamination in the boundary of copper/copper-epoxy layers was caused by the thermal mismatch and growth of micro voids during the thermal reflow process. The maximum deformation on the capacitor during reflow was 2.370 µm. It was found that a larger void would induce higher vicinity stress, mode I stress intensity factor, and crack elongation rate. Moreover, the crack extension increased with the exerted deformation until 0.3 µm, before saturating at the peak crack extension of around 0.078 µm.

The root cause of interfacial delamination issues in capacitors due to thermal reflow has been identified, and viable solutions proposed. These can eliminate the additional manufacturing cost and lead time incurred in identifying and tackling the issues; as well as benefit end-users, by promoting the electronic device reliability and performance.

To the best of the authors’ knowledge, the mechanism of delamination occurrence in a capacitor during has not been reported to date. The parametric variation analysis of the void size and deformation on the crack growth has never been conducted.

Reflow solder joint quality is significantly affected by the ability of the solder to perfectly fill pad space and retain good solder joint shape. This study aims to investigate solder joint quality by quantitatively analyzing the stencil printing-deposited solder volume, solder height and solder coverage area.

The dispensability of different solder paste types on printed circuit board (PCB) pads using different stencil aperture shapes was evaluated. Lead-free Type 4 (20–38 µm particle size) and Type 5 (15–25 µm particle size) solder pastes were used to create solder joints according to standard reflow soldering.

The results show that the stencil aperture shape greatly affects the solder joint quality as compared with the type of solder paste. These investigations allow the development of new strategies for solving solder paste stencil printing issues and evaluating the quality of solder joints.

The reflow soldering process requires the appropriate selection of the stencil aperture shape according to the PCB and the solder paste according to the particle-size distribution of the solder alloy powder. However, there are scarce studies on the effects of stencil aperture shape and the solder alloy particle size on the solder paste space-filling ability.

This study aims to investigate the NiO nano-reinforced solder joint characteristics of ultra-fine electronic package.

Lead-free Sn-Ag-Cu (SAC) solder paste was mixed with various percentages of NiO nanoparticles to prepare the new form of nano-reinforced solder paste. The solder paste was applied to assemble the ultra-fine capacitor using the reflow soldering process. A focussed ion beam, high resolution transmission electron microscopy system equipped with energy dispersive X-ray spectroscopy (EDS) was used in this study. In addition, X-ray inspection system, field emission scanning electron microscopy coupled with EDS, X-ray photoelectron spectroscopy (XPS) and nanoindenter were used to analyse the solder void, microstructure, hardness and fillet height of the solder joint.

The experimental results revealed that the highest fillet height was obtained with the content of 0.01 Wt.% of nano-reinforced NiO, which fulfilled the reliability requirements of the international IPC standard. However, the presence of the NiO in the lead-free solder paste only slightly influenced the changes of the intermetallic layer with the increment of weighted percentage. Moreover, the simulation method was applied to observe the distribution of NiO nanoparticles in the solder joint.

The findings are expected to provide a profound understanding of nano-reinforced solder joint’s characteristics of the ultra-fine package.

This paper aims to investigate the characteristics of ultra-fine lead-free solder joints reinforced with TiO₂ nanoparticles in an electronic assembly.

This study focused on the microstructure and quality of solder joints. Various percentages of TiO₂ nanoparticles were mixed with a lead-free Sn-3.5Ag-0.7Cu solder paste. This new form of nano-reinforced lead-free solder paste was used to assemble a miniature package consisting of an ultra-fine capacitor on a printed circuit board by means of a reflow soldering process. The microstructure and the fillet height were investigated using a focused ion beam, a high-resolution transmission electron microscope system equipped with an energy dispersive X-ray spectrometer (EDS), and a field emission scanning electron microscope coupled with an EDS and X-ray diffraction machine.

The experimental results revealed that the intermetallic compound with the lowest thickness was produced by the nano-reinforced solder with a TiO₂ content of 0.05 Wt.%. Increasing the TiO₂ content to 0.15 Wt.% led to an improvement in the fillet height. The characteristics of the solder joint fulfilled the reliability requirements of the IPC standards.

This study provides engineers with a profound understanding of the characteristics of ultra-fine nano-reinforced solder joint packages in the microelectronics industry.

The findings are expected to provide proper guidelines and references with regard to the manufacture of miniaturized electronic packages. This study also explored the effects of TiO₂ on the microstructure and the fillet height of ultra-fine capacitors.

This paper focuses on the reliability of the solder joint after the self-alignment phenomenon during reflow soldering. The aim of this study is to analyse the joint quality of the self-alignment assemblies of SnAg alloy solder joints with varying silver content.

The shear strength assessment was conducted in accordance with the JIS Z3 198-7 standard. The standard visual inspection of IPC-A-610G was also performed to inspect the self-alignment features of the solder joint samples. Statistical analysis was conducted to determine the probabilistic relationship of shear strength of the misalignment components.

The results from the mechanical reliability study indicate that there were decreasing trends in the shear strength value as misalignment offset increased. For shift mode configuration in the range of 0-300 µm, the resulting chip assembly inspection after the reflow process was in line with the IPC-A-610G standard. The statistical analysis shows that the solder type variation was insignificant to the shear strength of the chip resistor. The study concluded that the fracture occurred partially in the termination metallization at the lower part of the chip resistor. The copper content of the joint on that area shows that the crack occurred in the solder joint, and high silver content on the selected zone indicated that the fracture happened partially in the termination structure, as the termination structure of the lead-free chip resistor consists of an inner layer of silver and an outer layer of tin.

This study’s findings provide valuable guidelines and references to engineers and integrated circuit designers during the reflow soldering process in the microelectronics industry.

Studies on the effect of component misalignment on joint mechanical reliability are still limited, and studies on solder joint reliability involving the effect of differing contents of silver on varying chip component offset are rarely reported. Thus, this study is important to effectively bridge the research gap and yield appropriate guidelines in the potential industry.