Electrochemical deposition of reactive nanoscale metallization systems for low temperature bonding in 3D integration

In the face of the demand for low temperature bonding processes in the 3D Integration of microelectronic or micromechanical components we want to introduce a method that uses a specific form of heat production. It is based on reactive material systems that consist of several layers of two different materials with nanoscale thicknesses. These layers show a self propagating and exothermic reaction during their joint intermixing. The resulting heat can be used as source for bonding processes such as solid liquid interdiffusion bonding. By arranging the reactive system in between the joining partners together with a solder layer the heat generation can be limited only to the joint interface while preventing heating of the whole device. Whereas others showed the fabrication of foils of such systems, that have to be placed between two joining parts by pick-and-place handling, we focused on the direct deposition of such reactive multilayer systems. The principle of this method is demonstrated by sputter deposition. The main part of this paper deals with the development of the electrochemical deposition of such reactive multilayers.