Studies on development of lead free solder alloy made by mechanical alloying.

Practically all-conventional microelectronic assemblies use Sn -Pb solders for interconnection. With the advent of the microchip scale packaging technologies, the usage of solder interconnection has increased. The most commonly used Sh-Pb solder has a eutectic composition. However, with increasing environmental awareness use of Pb in solder has come under the threat of environmental regulations, due to inherent toxicity of Pb. The development of Pb free solder for microelectronic applications has become a major field of research in the interconnection materials. The present investigation is concerned with an alloy system consisting of Sn-Ag-Bi along with elements, made by mechanical alloying technique. The alloy thus formed was characterised by X-ray Diffraction (XRD), Differential Scanning calorimetry (DSC), Scanning electron microscopy (SEM) and Inductive coupled plasma- Atomic emission spectroscopy (ICP-AES). Solderability testing was performed on alloy to find contact angle and area of spreading. The solder/substrate interface was characterised by SEM/EDAX. The results of mechanically alloyed solder were compared with atomised lead free solder powder.