Electroplating of Palladium‐based integrated Reactive Multilayer Systems (iRMS)

Bonding with integrated reactive material systems enables joining of heterogeneous substrates at room temperature. The increasing diversity of electronic modules raises the demand for low temperature bonding processes for heat sensitive components. In this paper, fundamental steps for the deposition of Pd/In multilayers from a single bath electrolyte are presented. It furthermore describes the deposition of Pd/Sn reactive multilayers for bonding application on ceramic substrates and introduces a new semi-automated plating tool for Pd/Sn multilayers. The Pd/Sn multilayers can be deposited reproducible on silicon and ceramic substrates. While a bilayer period of 425 nm enables stable ignition and bonding of Si substrates, the bilayer period for ceramics has to be increased to 620 nm to compensate the higher heat dissipation into the substrate. By integrating 2.5 µm to 9 µm thick Sn compensation layers beneath the iRMS to smoothen the surface profile of the printed metallization and an improved bonding processes with wedge compensation, a homogeneous bond along the whole interface can be achieved.