Reactive Multilayer Foils: Fabrication, Characterization, Applications

Reactive multilayer foils have attracted intense research attention in recent years, expecially for their applications as local heat sources in joining. In this study, reactive multilayer foils are fabricated by a cold rolling method. Unlike the generally physical vapor deposited multilayers, the cold rolled foils possess unique combustion synthesis behaviors due to their unique structures. They provide an ideal opportunity to study the details of the synthesis process in different reactive multilayer systems. Silicon wafers are successfully bonded using reactive Ni/Al multilayer foils as local heat sources. The localized heating and rapid cooling nature of reactive foil bonding make this process an ideal method for silicon wafer bonding and MEMS wafer level packaging applications. These results should help shed some light on the development of simple and cost effective fabrication methods for reactive multilayer foils, and should be especially useful for professionals and students in the material synthesis and MEMS and microelectronics packaging fields.