Additive nano-manufacturing of 3D printed electronics using supersonic cluster beam deposition

Additive manufacturing approaches rely on the fabrication of an object directly from its virtual model by joining materials in a layer-by-layer fashion, at odd with classical subtractive techniques. This fabrication route enables the production of 3D freeform components and systems using a variety of materials, and it is increasingly employed for the realization of smart devices with embedded electronics, where different functionalities coexist in the same monolithic platform. This challenging task is nowadays limited by the use of metallic or organic conductive inks that are printed on three-dimensional polymeric substrates, presenting relatively poor adhesion to the polymer, low spatial resolution, and geometry-dependent electrical properties of the printed elements. Moreover, this strategy does not allow for the fabrication of out-of-plane interconnects and vias to electrically join different layers of the system. This chapter presents and discusses the use of Supersonic Cluster Beam Deposition (SCBD) as an enabling additive technology for the prototyping of 3D monolithic smart objects and polymer-based functional devices with controlled electrical properties. SCBD is an additive nanofabrication technique for the printing of polymer/metal nanocomposites with tailored electrical conductivity and mechanical properties that can be tuned by regulating the amount of nanoparticles constituting the structures. The combination of standard additive manufacturing of thermoplastic polymers and the bottom-up additive assembling of metallic nanoobjects has demonstrated to be a suitable solution for the fabrication of freeform devices with 3D polymer/metal nanocomposite lines, simplified circuit topology, 3D bridge vias, and out-of-plane electrical connections, as well as resistors with tailored electrical conductivity and sockets for standard electronic components fitting.