Minimal multi-target plasma sputtering tool

A multi-target plasma sputtering tool is developed for a recently progressed new concept of a semiconductor fab system called ‘Minimal Fab’. A frequency-tuning compact helicon plasma source is attached on the side wall of the compact vacuum chamber and the plasma is transported along curved magnetic field lines to a target surface, which is mounted on a rotational target holder and negatively biased by a dc power supply. The target material is sputtered by the ions accelerated by the sheath potential drop and deposited on the substrate facing the target. The target material can be changed by rotating the holder; thereby the multi-layered metallic film can be formed in the single chamber. Substrate heating induced by secondary electrons emitted from the target surface and accelerated by the sheath is successfully inhibited by a magnetic filter near the substrate. The performance of the sputtering reactor designed as a laboratory model is shown here. The sputtering reactor and all of the components required for the sputtering tool are successfully contained within a compact frame of Minimal Fab (29.5 cm in width, 45 cm in depth, and 144 cm in height) via the development of the compact reactor, especially the compact rf plasma source.