The landmark Directive of RoHS passed by EU in 2002 became effective in 2006 to ban six toxic materials used in electrical and electronic equipment. Since then, this legislation has made a global impact in the electronic industry.
The author has significantly contributed last 25 years in the successful implementation of Pb-free solders. In 1995, well before the RoHS legislation, the author has established an IBM-KAIST joint study program to investigate the fundamental topics of Pb-free solder joints used for electronic packaging applications. This program has lasted more than 15 years until 2013, and remarkably accomplished to enhance our basic understandings on many important reliability issues of Pb-free solder interconnections. In this talk, several key findings of the challenging reliability issues of Pb-free solder science & technology are reviewed, including the topics such as interfacial reactions, thermal fatigue, oxidation, minor alloying effects, electromigration, tin whiskers, and others.