Plasma enhanced CVD process using a dual magnetron as plasma source
Medium frequency (MF) dual magnetron sputtering with MF power supplies is a sophisticated technology for coating of polymer webs with optical layer stacks and permeation barrier layers. In this paper we will present a technology to use dual magnetrons as plasma source for a PECVD (plasma enhanced chemical vapour deposition) process. The benefits of this technology are: stable, well controlled process conditions based on magnetron technologies in-line combination of PECVD and sputtering processes in multi-cathode sputter roll coaters lower thermal load when compared to sputtering processes The technology can be used for optical layer stacks and barrier coatings: For optical layers, thermal load problems may occur when a thick coating is in-line combined with a very thin coating. The thermal load related to the thick coating may limit the overall process speed. The PECVD process would allow reducing thermal load and therefore increasing web speed. Single permeation barrier coatings suffer from defects. We therefore propose a multilayer stack of sputtered layers and PECVD layers. The technology has been implanted in an industrial sputter roll coater with 700 mm web width.