Improved Adhesion of DLC and Polymeric Films using Carbon-based Interlayer Coatings

摘要

Thin film coatings are becoming an important and integral part of advanced medical prosthesis and sensors. They introduce new and improved functionalities to these devices. One of the most important issues that can determine the success or failure of the deposition process is film adhesion. Plasma- and ion beam-based treatments, as well as multi-layer coatings can improve film adhesion substantially. In this paper we describe the results of treatment processes using Plasmionique's plasma-based surface treatment systems. In particular we discuss the role of thin carbon-based interlayer coatings as a transition layer for the deposition of a hard diamond-like carbon (DLC) coating and a polymeric conformal coating (parylene or para-n-xylylene) on materials such as titanium and stainless steel that have widespread applications in the manufacturing of prosthesis and medical instruments as well as on materials of general applications such as silicon and aluminum. We have observed that a thin carbon-based interface layer produced while a pulsed d.c. bias voltage was applied to the substrate in a low pressure plasma environment can improve adhesion. The optimum bias voltage is proportional to the gas pressure, indicating that the energy of the ions impinging on the surface of the substrate plays a critical role in the formation of an effective transitional layer.