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Purpose: This paper aims to investigate the effect of different doses of gamma radiation on the micromechanical response (hardness properties and creep behaviour) of 96.5Sn-3.0Ag-0.5Cu (SAC305) solder alloys. Design/methodology/approach: SAC305 solder pastes deposited on printed circuit boards (PCBs) were subjected to a reflow soldering process to form soldered samples. The soldered samples were irradiated with a gamma source at different doses (5–50 Gy). Nanoindentation testing was used to determine the hardness properties and creep behaviour after gamma irradiation. Findings: The results showed that the hardness of SAC305 solder alloys gradually increased up to 15 Gy and then gradually decreased to 50 Gy of gamma irradiation. The highest hardness value (0.37 GPa) was observed on SAC305 solder alloys exposed to 15 Gy irradiation. Hardening of SAC305 solder alloy was suggested to be due to the high defect density induced by the gamma irradiation. Meanwhile, exposure to 50 Gy irradiation resulted in the lowest hardness value, 0.13 GPa. The softening behaviour of SAC305 solder alloy was probably due to the evolution of defect size in the solder joint. In addition, the creep behaviour of the SAC305 solder alloys changed significantly with different gamma irradiation doses. The creep rates were higher at a dose of 10 Gy up to a dose of 50 Gy. Gamma irradiation caused the SAC305 solder alloy to become more ductile compared to the non-irradiated alloy. The stress exponent also showed different deformation mechanisms with varying gamma doses. Originality/value: Research into the micromechanical properties of solder alloys subjected to gamma irradiation has rarely been reported, especially for Sn-Ag-Cu lead-free solder. Thus, this research provides a fundamental understanding of the micromechanical response (hardness and creep behaviour) of solder, especially lead-free solder alloy, to gamma irradiation. [ABSTRACT FROM AUTHOR]

Electronic applications are now driving packaging technology that is equivalent to primary computer packages for the past 25 years. The electronic application currently shows an ascending market demand due to rapid development of smart and wireless component with mixed technologies that include digital microprocessors. In ensuring the quality of the devices, the reliability of the solder joint is very vital. Attributable to their common uses, radiation particles including gamma ray is considered as one of the primary factors that could degrade the performance of the electronic devices. Thus, in this study, both mechanical and microstructure properties of lead-free solder joints radiated with gamma were investigated. Prior to the evaluation, the solder pastes of tin–silver–copper (SnAg3Cu0.5; SAC305) was manually deposited on the printed circuit board using a stencil printing method and reflow soldering process. Subsequently, the solder was exposed to low doses of gamma radiation. The current finding showed that as the radiation dose increased, the solder sample became softer and more plastic. FESEM and EDS analysis signified that intermetallic layer in the tin (Sn) matrix was dominated by Cu6Sn5 and Ag2Sn compound. According to micromechanical investigation, both hardness and reduced modulus of the solder decreased with increasing the radiation dose that was due to microstructure change and the formation of voids. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to discuss the effect of a blast wave on the microstructure, intermetallic layers and hardness properties of Sn0.3Ag0.7Cu (SAC0307) lead-free solder.Design/methodology/approach Soldered samples were exposed to the blast wave by using trinitrotoluene (TNT) explosive. Microstructure and intermetallic layer thickness were identified using Alicona ® Infinite Focus Measurement software. Hardness properties of investigated solders were determined using a nanoindentation approach.Findings Microstructure and intermetallic layers changed under blast wave condition. Hardness properties of exposed solders decreased with an increase in the TNT explosive weight.Originality/value Microstructural evolution and mechanical properties of the exposed solder to the blast wave provide a fundamental understanding on how blast waves can affect the reliability of a solder joint, especially for military applications. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]