Solidification and reliability of lead-free solder interconnection

Purpose - As a literature review article, the purpose of this paper is to highlight the intricate interaction and correlation between the interconnection microstructure and the failure mechanism. It is therefore critical to summarize all the challenges in understanding solder solidification of interconnections.Design methodology approach - Literature review.Findings - Solidification of solder interconnections is therefore critical because it is the process during which the solder interconnection is formed. The as-solidified microstructure serves as the starting point for all failure modes. Because of the miniaturization of electronics, the interconnection size decreases continuously, already to such a range that solder solidification takes place remarkably differently from the bulk ingot, on which solidification studies have been focused for decades. There are many challenges in understanding the solidification of tiny solder interconnections, including the complex metallurgical system, dynamic solder composition, supercooling and actual solidification temperature, localized temperature field, diverse interfacial IMC formation, and so on, warranting further research investment on solder solidification.Originality value - This paper provides a critical overview of the concerns in solidification study for lead-free solder interconnection. It is probably an article initiating more attention towards solidification topics.