Effects of plating parameters on alloy composition and microstructure of Sn–Bi electrodeposits from methane sulphonate bath

Electrodeposition of Sn–Bi lead-free solders: Effects of complex agents on the composition, adhesion, and dendrite formation

“…Tin-lead solders were considered as the most prominent material for the interconnection and packaging of electronic components [1][2][3], which was originally deposited by means of a vacuum evaporation technique developed by IBM [4]. In order to increase the density of interconnections, a variety of new methods/processes were developed to form solder bumps, especially the electroplating process [5,6].…”

“…In order to increase the density of interconnections, a variety of new methods/processes were developed to form solder bumps, especially the electroplating process [5,6]. However, on July 1st 2006, European Union (EU) mandated a switch to use lead-free solders in many of the electronic assembly processes because of the environmental and health considerations [1,3,5,7,8]. Accordingly, lead-free processes for electronic devices and components are profoundly required and the development of lead-free solders (e.g., Sn-Cu, Sn-Bi, Sn-Ag, Sn-Ag-Cu, Sn-Zn, etc.)…”

“…Accordingly, lead-free processes for electronic devices and components are profoundly required and the development of lead-free solders (e.g., Sn-Cu, Sn-Bi, Sn-Ag, Sn-Ag-Cu, Sn-Zn, etc.) becomes an urgent assignment in modern electronic industries [1][2][3][4][5][6][7][8][9][10][11].…”

Drop Reliability of Epoxy-contained Sn-58 wt.%Bi Solder Joint with ENIG and ENEPIG Surface Finish Under Temperature and Humidity Test

“…[9][10][11] In particular, Sn-58 wt.%Bi alloy with eutectic composition has low melting temperature of 138°C, showing that it is possible to reflow at low processing temperature. 12 Low-temperature soldering is necessary because electronic devices are prone to thermal damage during high-temperature reflow processing, which damages not only the solder joints but also the printed circuit board (PCB) and components. Also, low-temperature soldering reduces the risk of warpage problems induced by coefficient of thermal expansion (CTE) mismatch between different materials in the electronic package.…”

Evaluation of the Bondability of the Epoxy-Enhanced Sn-58Bi Solder with ENIG and ENEPIG Surface Finishes

“…Also, low-temperature reflow is necessary in order to reduce the risk of warpage problems in the flexible printed circuit board (PCB) substrate, which usually induces alignment problems of components during the surface-mounting process and the mismatch of the coefficients of thermal expansion (CTE) between different materials in electronic packages. [15][16][17][18] However, besides exhibiting a desirable low reflowing temperature, Sn-Bi alloys have a critical property issue of brittleness, which can be a critical problem for solder joints in portable devices. 19 In order to compensate for this disadvantage of Sn-Bi alloys, it has been shown that adding small amounts of Ag can refine the microstructure of the Sn-58Bi alloys through the formation of ''Ag 3 Sn'' compounds and thereby improve their plasticity.…”