**1.2. Microelectronic packaging materials**

Since the civilization, the most commonly used solder is lead–tin (Sn–Pb) solder in electronic packaging. However, the toxicity of Pb is a serious concern among the electronic manufactur‐ ers. Pb containing solders are in use so far due to their indispensable properties. The effect of Pb contamination on human beings is a serious threat nowadays. Therefore, Pb and its compounds in electronic devices are now being restricted on account of the bans and regulation imposed by European organizations such as restriction of hazardous substances and waste electrical and electronic equipments.[3–5] It is also to be noted that, though Pb is cost effective, available in abundance, and provides no undesirable reaction with the substrate, yet it shows some technical problems like inferior bonding strength which is important for microjoining.[1– 6] Therefore, composites solders are now being regarded as an alternative to conventional Sn– Pb solders and developed to resolve these concerns.
