Effects of Ni modified MWCNTs on the microstructural evolution and shear strength of Sn-3.0Ag-0.5Cu composite solder joints

Materials modification of the lead-free solders incorporated with micro/nano-sized particles: A review

Influence of dual ceramic nanomaterials on the solderability and interfacial reactions between lead-free Sn-Ag-Cu and a Cu conductor

This study investigates the capacity of the nano-indentation method in the mechanical characterization of a heterogeneous dental restorative nanocomposite using experimental and computational approaches. In this respect, Filtek Z350 XT was selected as a nano-particle reinforced polymer nanocomposite with a specific range of the particle size (50 nm to 4 µm), within the range of indenter contact area of the nano-indentation experiment. A Sufficient number of nano-indentation tests were performed in various locations of the nanocomposite to extract the hardness and elastic modulus properties. A hybrid computational-experimental approach was developed to examine the extracted properties by linking the internal behaviour and the global response of the nanocomposite. In the computational part, several representative models of the nanocomposite were created in a finite element environment to simulate the mechanism of elastic-plastic deformation of the nanocomposite under Berkovich indenter. Dispersed values of hardness and elastic modulus were obtained through the experiment with 26.8 and 48.5 percent average errors, respectively, in comparison to the nanocomposite properties, respectively. A disordered shape was predicted for plastic deformation of the equilateral indentation mark, representing the interaction of the particles and matrix, which caused the experiment results reflect the local behaviour of the nanocomposite instead of the real material properties.

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Assessment of Nano-Indentation Method in Mechanical Characterization of Heterogeneous Nanocomposite Materials Using Experimental and Computational Approaches.

In recent times, wearable electronics, real-time sensing devices and point-of-care device applications have seen a surge in demand. This demand inherently calls for a more economic and reliable method of mass production. One such robust technique is screen printing that offers advantages in terms of being versatile, economical and easy to use. This technique has been proclaimed to be the best amongst the other additive manufacturing techniques by many research groups. This can be solely attributed to its simple equipment design, requiring a paste for printing purpose, a meshwork for housing the design and a squeegee to carry out printing through an up-and-down motion. This subsequently calls for optimising the parameters such as ink rheology, pore size of the mesh, proper choice of mesh design and motion of the squeeze in order to fabricate electrodes for desired purpose. Due to this technique’s immense potential to open up broad inroads in the domain of flexible electronics, whose concept has radically redefined the perception towards the field of electronics, a review article encompassing an elaborate description on the science and other quintessential parameters involved in this mass printing technique would prove to be extremely useful. In this purview, the review article is compartmentalised into sections encompassing discussion on the manufacturing of different kinds of inks for screen printing applications, substrates used, electrode design and pre-treatment procedures.

Fabrication of screen-printed electrodes: opportunities and challenges

Purpose




This paper aims to investigate the characteristics of ultra-fine lead-free solder joints reinforced with TiO2 nanoparticles in an electronic assembly.




Design/methodology/approach




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.




Findings




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.




Practical implications




This study provides engineers with a profound understanding of the characteristics of ultra-fine nano-reinforced solder joint packages in the microelectronics industry.




Originality/value




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.

SAC-xTiO2 nano-reinforced lead-free solder joint characterizations in ultra-fine package assembly

Improvement of the hardness values of Sn-3.0Ag-0.5Cu-TiO 2 composite solders with different TiO 2 weight percentages was evaluated by nanoindentation. The composite solders were prepared by ball milling of Sn-3.0Ag-0.5Cu solder with TiO 2 nanoparticles at 300 rpm for 10 min prior to printing and reflowing. Structural analysis indicated that the TiO 2 nanoparticles were successfully blended into the Sn-3.0Ag-0.5Cu solder. Finer Cu 6 Sn 5 and Ag 3 Sn phases were observed in the composite solder micrographs. The optimum hardness of 1.775 GPa was obtained for the composite solders with a TiO 2 content of 1 wt%. A further increment of the TiO 2 content to 1.5 wt% significantly reduced the hardness value to 1.677 GPa. The hardness profiles were established based on the specific measurement pattern obtained from the nanoindentation. The mechanism of the influence of TiO 2 nanoparticles on the refinement of the intermetallic phases and improvement of the hardness value is also presented.

Hardness profiles of Sn-3.0Ag-0.5Cu-TiO2 composite solder by nanoindentation

Purpose




This study aims to investigate the NiO nano-reinforced solder joint characteristics of ultra-fine electronic package.




Design/methodology/approach




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.




Findings




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.




Originality/value




The findings are expected to provide a profound understanding of nano-reinforced solder joint’s characteristics of the ultra-fine package.

Characterization of SAC – x NiO nano-reinforced lead-free solder joint in an ultra-fine package assembly

Electrochemical migration and corrosion behaviours of SAC305 reinforced by NiO, Fe 2 O 3 , TiO 2 nanoparticles in NaCl solution

Electrochemical migration (ECM) of solder joining can result in the growth of a metal deposit with dendrite structure from cathode to anode. In electronic device, this phenomenon potentially leads to the incompetence or failure of whole devices. In this paper, the ECM behaviour of printed circuit boards (PCBs) with SAC 0307, one of the low-cost lead-free solder alloys with less silver content, has been studied. The corrosion behaviour of SAC 0307 has been investigated by using sodium chloride solution in different concentrations which is between 0.01 M to 1.0 M as a medium. A Water Drop Test (WDT) was carried out and the time-to-failure of each sample has been recorded. After WDT test, the dendrite phase was identified using Variable Pressure Scanning Electron Microscope (VPSEM) with Energy Dispersive X-ray Spectroscopy (EDX) and X-ray Photoelectron Spectroscopy (XPS) to investigate its surface morphology and corrosion products. As results, it has been found that the corrosion susceptibility of SAC 0307 is greatly influenced by the concentration of the medium solution used. The voltage drop occurred was due to the dendrite grew at the cathode electrode on the PCBs and expanded to the anode electrode, indicating a significant effect of aggressive behaviour of the medium used. The rate of the dendrite growth was affected by the concentration of the medium used. The main element found in the dendrites on the SAC 0307 on PCBs was Tin as it is more mobile than Cu.

Fakhrozi Che Ani

Papers

SAC-xTiO2 nano-reinforced lead-free solder joint characterizations in ultra-fine package assembly

Hardness profiles of Sn-3.0Ag-0.5Cu-TiO2 composite solder by nanoindentation

Characterization of SAC – x NiO nano-reinforced lead-free solder joint in an ultra-fine package assembly

Electrochemical migration and corrosion behaviours of SAC305 reinforced by NiO, Fe 2 O 3 , TiO 2 nanoparticles in NaCl solution

Electrochemical Migration Behaviours of Low Silver Content Solder Alloy SAC 0307 on Printed Circuit Boards (PCBs) in NaCl Solution