Process Benefits of Wide Area, Low Energy End-Hall Ion Source for Surface Pre-Cleaning and Functional Treatment of Polymeric Substrate Materials

The low ion energy and high current flux of broad-area gridless end-Hall ion sources can have significant advantages over high-energy gridded or gridless ion source systems when processing glass and engineering thermal plastics. Specifically the lower energy spectrum of such ion sources are shown to improve surface energy and adhesion with limited process exposure times and while inducing very limited optical, thermal or sub-surface layer damage which leads to mechanical embrittling, deformation and optical yellowing. We examine fundamental surface treatment properties of multiple materials (glass, polyamide 6.6, polycarbonate, thermoplastic polyurethane, poly(tetrafluoroethene), and polyethylene terephtalate) when processed under identical conditions in pure oxygen and argon-oxygen blends using contemporary end-Hall ion source technology. Water contact angles, optical transparency, substrate thermal damage of treated surfaces are reported along with adhesion performance of PVD sputtered titanium and diamond-like carbon films. Optimal reduction in surface contact angle is noted for most all materials with the inclusion of 15-30% of oxygen with little to no change in optical transparency. In addition to these results, typical treatment rates are deduced against ion beam current dosage to help process developers scale end-Hall ion source systems to various wide-area batch and in-line vacuum treatment  applications.