Anisotropic Conducting Film (ACF) of Ag Nanoparticles as Transfer Polymer and Electrical Interface for Silicon Micro- and Nano- Pillars

Abstract

We report a novel application of Anisotropic Conductive Films (ACFs) technology to provide electrical contact and mechanical anchor between fracture transfer-printed (1-D) single crystal semiconductor micro- and nanopillars and a bottom metal. This fracture-transfer method enables highly crystalline micro- and nanopillars of different materials with diverse bandgaps and physical properties to be fabricated on appropriate mother substrates and transferred to form multilayered 3D stacks for multifunctional devices. The proposed protocol incorporates silver (Ag) nanoparticles into thermoplastic polymers exploitable in transfer-printed semiconductor devices and circuits with low contact resistance that is compatible with current IC processing methods. The vertical micropillars arrays are then embossed onto the polymer at its rubbery state by applying a vertical force leading to particle trapping between the bottom electrode and the micropillars. The polymer is then hardened while retaining the applied vertical force. By applying a lateral force on the mother substrate, the firmly cemented pillars are fractured off thereby allowing the mother substrate to be reused.