High Step Coverage Interconnects By Printed Nanoparticles

The growing diversity in the used materials in semiconductor packaging provides challenges for achieving good interconnection. Particularly the very soft substrates, such as paper and polymers, and very hard, such as silicon carbide, offer unique challenges to wire-bonding or formation of vertical interconnects. Complementary technologies are therefore needed. Here, a method to direct-write metal tracks on the top and sides of dies is demonstrated. It is based on a spark ablation aerosol printing process entirely performed at room temperature and without any applied force. Therefore, it is suitable for use on soft or temperature-sensitive substrates. The printed metal lines consist of pure Au nanoparticles, without surfactants or contaminants, and do not require any further curing, cleaning, or other processing. The process is demonstrated on Si dies and paper, but is theoretically applicable on a wide variety of substrate materials. It can provide an alternative method to create interconnects or vias on soft materials, temperature sensitive materials, irregularly shaped materials, or curved surfaces.