3D LTCC and flexible structure interconnections based on galvanized layers

Interconnections have an important role in packaging as they not only provide electrical connection but they also act as mechanical attachment between connected substrates and are supposed to be as reliable as possible. This paper describes design, construction and some recent laboratory tests of 3D stacked structures, where different materials with different coefficient of thermal expansion are combined together in one package. Goal of this work is to develop reliable 3D stacked structure interconnection method, which will allow connection between LTCC, Al₂O₃ and also flexible substrates. Vacuum evaporated and galvanically enhanced layers in connection with solder balls are used to create interconnections between substrates.