High-Quality Conductive Bellows Coatings Using Conformal Ionized PVD To Replace Unreliable Electroplating Processes

High-quality and functionalized material surfaces are essential for next-generation particle accelerators supporting nuclear physics research, i.e. LCLS-II. Traditionally coatings and surface functionalization are performed with wet chemistry/electroplating; however, process irreproducibility, contamination and ever decreasing supplier base as environmentally-unfriendly wet chemistry is phased out has led to repeated component failures, more risk, higher cost and delayed timelines. Both FNAL and JLAB recently faced this challenge coating high-conductivity copper onto flexible de-coupling bellows for the LCLS-II cryomodule upgrade. A recent sputtering innovation at high powers—the IMPULSE + Positive Kick—enables dense plasma positive sheaths and adjustable ion energy control to surfaces for conformal deposition of dense, ultra-smooth thick films onto 3D shapes with control of purity, particles, adhesion, stress, morphology and crystallinity. The goal of this SBIR is to demonstrate the deposition of particulate- free, adherent, thick-film conductive coatings, specifically for use in the bellows, spool and flange sections of particle accelerators for LCLS-II and beyond—to replace wet chemical electroplating. The IMPULSE + Positive Kick technology provides ion energy by reversing the potential across the magnetic field of the sputtering magnetron—turning it into a miniature Hall-Effect Thruster momentarily with precision user control at the eV energies such that both deposition and etching can be simultaneously performed and surfaces functionalized. The technology is ideal for reactive depositions such as oxides and nitrides. Benefits include superior coatings on older accelerator beam pipe surfaces to lower resistance, smoothen for higher gradients and decreased electron emission, and improved thermal conductivity. The technology also has application for advanced high-density microelectronic packaging to replace wet chemical copper plating to enable high-density redistribution layers and vias. The technique will also support industrial accelerators in order to provide low cost, reliability and long-term stable operation. The SBIR program will also support emerging small businesses and job creation in the Midwest.