Reactive Bonding and Low Temperature Bonding of Heterogeneous Materials

This paper describes alternative low-temperature bonding procedures in Microsytems Technology. On the one hand reactive bonding is introduced, which is a relatively new joining technique for the mounting of microelectric components and the hermetic sealing of microelectronic packages. The usage of commercially available Ni/Al foils is demonstrated for room-temperature bonding an IR-emitter onto a covar socket. Furthermore integrated nano scale multilayer films of aluminum and titanium as well as titanium and amorphous silicon were magnetron sputter deposited and characterized. On the other hand surface activating procedures prior to bonding, like low- and atmospheric-pressure plasma, are presented. The wafer level bonding was examined for silicon to lithium tantalate (LiTaO3) and Foturan{copyright, serif} by using CMP-processes and plasma activation. The bond strength was characterized by micro chevron test to evaluate the different bonding, plasma and annealing conditions. The results showed that with the surface activation the bond strength can be dramatically enhanced.