As a continuation of the PAK984/1 project, the application of reactive metallic multilayer systems (RMS) in the field of microscale connections in electronics assembly and connection technology is being investigated. The focus here is on the potential of using reactive multilayers in order to be able to adjust a desired joining process via a predefined layer structure or morphology for joining partners with low or strongly differing thermal conductivities. While the vast majority of previous studies in the field of RMS bonding have always investigated the bonding of Si with Sl, metal with metal and Si with metal, the investigations in this project focused on the reactive bonding of two ceramic LTCC substrates or of silicon with LTCC substrates. The knowledge gained from the preliminary project that, in addition to the thermal conductivity, the surface roughness has a decisive influence on the formation of the directly deposited reactive multilayer coatings and subsequently on the reaction process, will be included in the investigations. Due to the partly unexpected findings that were obtained in the first project phase, the original objectives of the follow-up project will focus more strongly on developing a better understanding of the adhesion mechanisms for RMS bonding of thermally low conductive substrates such as the glass ceramics used. A model is to be developed that describes the reciprocal relationships between boundary conditions (thermal conductivity, roughness, layer thicknesses, etc.) and process parameters (reaction speed and temperature) and their effect on the bonding adhesion. On the experimental side, this goes hand in hand with the development of a new type of in-situ test substrate that allows direct temperature measurement during the reaction at the joint.
