Effect of ultrasonic vibration on interfacial reaction of Ni/Sn/Ni soldered joint

Abstract

Purpose This paper aims to investigate the effect of ultrasonic vibration (USV) on the evolution of intermetallic compounds (IMCs), grain morphology and shear strength of soldered Ni/Sn/Ni samples. Design/methodology/approach The Ni/Sn/Ni joints were obtained through ultrasonic-assisted soldering. The formation of IMCs, their composition, grain morphology and the fractured-surface microstructures from shear tests were characterized using scanning electron microscopy and energy-dispersive x-ray spectroscopy. Findings Without USV, a planar interfacial Ni3Sn4 layer was formed at the Ni/Sn interface, and a few Ni3Sn4 grains were distributed in the soldered joint. The morphology of these grains was needle-shaped. With USV, several grooves were formed at the interfacial Ni3Sn4 layer due to ultrasonic cavitation. Some deepened grooves led to “neck” connections at the roots of the Ni3Sn4 grains, which accelerated the strong detachment of Ni3Sn4 from the substrate. In addition, two types of Ni3Sn4 grains, needle-shaped and granular-shaped, were observed at the interface. Furthermore, the shear strength increased with longer USV time, which was attributed to the thinning of the interfacial IMC layers and dispersion strengthening from the Ni3Sn4 particles distributed evenly in the joint. Originality/value The novelty of the paper is the detailed study of the effect of USV on the morphology, size changes of interfacial IMC and joint strength. This provides guidance for the application of ultrasonic-assisted soldering in electronics packaging.

Effect of external static magnetic field on the particle distribution, the metallurgical process and the microhardness of Sn3.5Ag solder with magnetic Ni particles

“…Because of the increasing awareness of environmental protection among the public, many countries have followed this practice and began to seek new lead-free solder to substitute the traditional harmful lead-based solder in the field of electronic packaging (Zeng and Tu, 2002;Lauro et al,2003;Seo et al, 2009;El-Ashram, 2005;Felberbaum et al, 2011;Wu et al, 2017). In recent years, the development of lead-free solder is very rapid and a variety of tin-based lead-free solder materials have appeared, such as Sn-Ag-Al (Xu et al, 2021), Sn-Bi (Xu et al, 2019), Sn-Cu (Kelly et al, 2021;Han et al,2021), Sn-3.5Ag-Cu (Shalaby et al, 2018), Sn-3.5Ag-xCu (Shalaby et al, 2017), Sn-Ag (Gumaan, 2020;Wang et al,2019), Sn-Ni (Lin, 2021;Liu et al,2019), Sn-Zn (Hu, 2021).…”