Method and apparatus whereby the interconnection of integrated circuit chips is obtained by means of multilayers of microcircuit conductors fabricated on at least one flexible dielectric film. Metallized conductors are fabricated and selectively connected on both sides of the film by means of metallized throughholes. One or more integrated circuit chips are bonded and interconnected to the flexible film and the sub-assembly is then bonded and interconnected to a ceramic substrate sub-assembly which also contains appropriate metallized conductors thereon. The substrate additionally includes an insulating dielectric layer intermediate the opposing metallizations between the substrate and the lower surface of the flexible dielectric film and includes selected windows fabricated therein so that appropriate interconnection between the substrate conductors and the flexible film conductors can be accomplished by thermocompression bonding while at the same time preventing undesired shorting between opposing metallizations. The integrated chip may be mounted on either face of the flexible dielectric film or when desirable bonded to the substrate.