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The growth of electronics product has increased rapidly and hence drive challenges among the designers as well as manufacturers to select the best electronic packaging materials for their products. Among those materials, lead free solders has become the best replacement for lead-containing solders even though its performance still could not meet the original specification. Thus, this paper is aiming at studying the effect Nickel (Ni) additional with difference percentage into solder alloy toward intermetallic compound formation (IMC) and growth at the interface of the solder joint. The work was carried out by producing Sn-xNi (x = 0.0, 0.3, 0.5, 0.7, 1.0) through powder metallurgy method. The process started with powder milling at the speed of 1400 rpm for 3 hours. Then it was compacted into a thin pallet with size of 6mm diameter at the pressure of 5 ton. After that, the sample were subjected to reflow soldering for 250˚C for 25min heating duration and 15min holding time. Solder joint strength was carried out using ASTM D1002. Finally, characterisation was made in terms of IMC morphology, thickness and solder joint strength using metallographic microscope as well as scanning electron microscopy-energy dispersive x-ray (SEM-EDX). Results showed that the addition of Ni with different percentage produced different morphology of IMC at the interface after reflow soldering which also affects its growth behaviour. The IMC’s formed after reflow soldering produced closed and packed grain boundary when solder with higher Ni content was used. The type of IMC formed at the solder joint was Cu6Sn5 and its thickness increased with Ni addition. These results were the proof that Ni is a good candidate to improve solder joint performance by restricting the formation and growth of Cu3Sn IMC. In addition, the solder joint strength was found to be increasing upon Ni percentage increment. The highest strength value of 5.885MPa was produce when Ni was added up to 1.0%. This showed that Ni not only a good candidate to improve joint performance in IMC formation but also help in strengthening the solder joint.

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Purpose Pb-free solders have been developed to replace the standard Sn–Pb eutectic solder since the prohibition on Pb used in solders. The Sn–Ag–Cu series of lead-free solders is the most extensively used in the electronics industry. The Ag3Sn, which forms during isothermal ageing, can significantly degrade solder joint reliability. Sn–Ag–Cu solder’s high price further hindered its use in the electronics industry. This paper aims to investigate different copper percentages into Sn–xCu solder alloy to improve its microstructure and strength performance. Design/methodology/approach The solder alloys used in this work were Sn–xCu, where x = 0.0, 0.3, 0.5, 0.7, 1.0 Wt.%, which was soldered onto electroless nickel immersion gold (ENIG) substrate using carbon dioxide (CO2) gas laser. Then these samples were subjected to isothermal aging for 0, 200, 500, 1,000 and 2,000 h. The Sn–xCu solder alloy was fabricated through a powder metallurgy process. Findings Microstructure characterization showed that Cu addition resulted in fine and rounded shape of Cu–Sn–Ni particles. Shear strength of Sn–xCu solder joints was increased with increasing Cu content, but at aging duration of 1,000 h, it dropped slightly. It is believed that the strength improved due to the increment of diffusion rate during isothermal aging. Practical implications In a Cu–Sn solder, the recommended amount is 1.0 Wt.% of Cu. In extensive aging procedures, it was discovered that Sn1.0Cu solder improved the reliability of solder joints. The findings indicated that the innovative solder alloys might satisfy the needs of high-reliability applications. Originality/value The study shows that the right amount of Cu enhances the solidification of Sn–Cu solder, increasing the shear force of the Cu–Sn solder joint. The Sn1.0Cu exhibits a ductile fracture on the top microstructure, improving the joint’s average shear strength.

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