Abstract Currently there is a great interest in flexible substrates for their use in the packaging of semiconductors. They allow high packaging density and permit mechanical motion of the components, if necessary. This paper describes a new substrate material which possesses a high flexibility and which can be used for the realization of interconnection cables and MCM-D. These substrates are not only highly flexible but also mechanically stable, chemically inert and can be produced with the same processes as those for rigid substrates.