Physical Properties of Copper Films Deposited by Compact-Size Magnetron Sputtering Source with Changing Magnetic Field Strength

An affordable 6-cm diameter magnetron sputtering source was designed and constructed using a neodymium cylindrical permanent magnet inner stud and an outer ring magnet. Both magnets were set in isolation from a water-cooled disk behind the target. In this work, our magnetron sputtering source was employed to deposit copper thin films by changing the outer magnet ring. The outer magnate ring diameter sizes were 29 mm (I.D.)/39 mm (O.D.) and 30 mm (I.D.)/50 mm (O.D.). At the same applied bias voltage, the discharge current of the magnetron with a big outer magnet was higher than that of one with a small outer magnet. According to XRD pattern and AFM image of copper films, the degree of (111) and (200) orientations and surface roughness were increased in the case of films grown by magnetron with bigger outer magnet. The cross-sectional and plane-view SEM images showed that the grain size and film thickness were increased in the case of films grown by magnetron with bigger outer magnet. These results should be because the radial motion of secondary electron emitted from sputtering in front of target surface was increased with a bigger magnet.