Joining small components with reactive multilayer foils

Reactive NanoTechnologies (RNT) has developed a new platform technology that will revolutionize how manufacturers join components using solder and braze materials. The joining process is based on the use of reactive multilayer foils as local heat sources. The foils are a new class of nano-engineered materials, in which self-propagating exothermic reactions can be ignited at room temperature with a spark. By inserting a multilayer foil between two solder (or braze) layers and two components, heat generated by the ignition of the reaction in the foil melts the solder and consequently bonds the components. The joining process can be completed in air, argon or vacuum in approximately one second. The use of reactive foils as a local heat source eliminates the need for torches, furnaces, or lasers, speeds soldering and brazing processes, and dramatically reduces the total heat that is needed. Thus, temperature-sensitive or small components can be joined without thermal damage or excessive heating. In addition, mismatches in thermal contraction on cooling can be avoided because components see very small increases in temperature. This is particularly beneficial for joining metals to ceramics. The fabrication and characterization of the reactive foils is described and an example of a joint is presented, showing the applicability of this platform technology to many areas of packaging including microelectronics, optoelectronics and MEMS.