Evaluation of a novel PECVD reactor for the intended continuous coating of flexible web material

Abstract

PET film samples were coated on a novel Plasma-Enhanced Chemical Vapor Deposition (PECVD) reactor. The reactor represents a pioneering development as the first of its kind to be designed for the continuous coating of plastic film. The reactor is equipped with sequentially arranged airlocks, that facilitate a gradual reduction in pressure from ambient pressure to process pressure levels of a few pascals. The airlocks are equipped with slits that facilitate the uninterrupted introduction and extraction of the web material. In the experiments presented however, the film was positioned manually in the reactor to eliminate any potential influence from sliding contacts or similar mechanical stresses associated with film transport. The leakage flows associated with the airlocks were present in a manner consistent with subsequent automated operation. An investigation of the leakages was published earlier.

In the study presented here, the utilization of OTR measurements was instrumental in demonstrating the potential to align the coating process with the airlock system. Depending on the position inside the coating area, barrier against oxygen was improved by factors of up to 29. Furthermore, coating thickness measurements were utilized to show that the coating of the reactor walls was significantly reduced by using a process envelope.