Deposition and characterization of copper thin films on a polymer surface by using a dc cylindrical magnetron sputtering technique

Abstract

AbstractIn the present study copper thin films were deposited on a polymer surface at room temperature using a specially developed DC cylindrical magnetron sputtering technique. The polymer chosen is light weight with a smooth surface. To have strongly adherent copper films, the polymer surface was initially etched for 2 hours by using an argon glow discharge created by a bi‐polar pulse power supply. After the etching treatment the water contact angle decreased from 75° to 9°. A dc cylindrical post magnetron, made from copper, was specially developed for depositing copper on the etched surface. The magnetron was biased to ‐800 V with typical discharge currents ∼ 200 mA. An axial magnetic field of 100 Gauss was applied to have EXB rotation of electrons. Argon was the sputtering gas during deposition at a pressure of 0.015 mbar. The sputtered copper was deposited on the etched polymer for 8 hours giving a film thickness of ∼12 μm. X‐ray diffraction studies showed the formation of polycrystalline copper film with sub‐100 nm crystallite sizes. Scanning electron microscopy showed the surface morphology. The cylindrical post magnetron was developed as it gave reduced deposition rate, and lower amount of stresses made the film strongly boned to the polymer surface. The article highlights the development of the cylindrical post magnetron and its use as a reliable coating device on various surfaces. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)