Metrology Enclosure Including Spectral Reflectometry System for Plasma Processing System Using Direct-Drive Radiofrequency Power Supply

A plasma processing chamber has an upper window with a coil disposed above the upper window. A coil connection enclosure is disposed above the coil. A metrology enclosure is disposed above the coil connection enclosure. A spectral reflectometry system is disposed within the metrology enclosure. The spectral reflectometry system includes an optical collimator positioned to direct a beam of light through an opening in the metrology enclosure, an opening in the coil connection enclosure, and the upper window into the plasma processing chamber. The optical collimator is also configured to receive reflected light from within the plasma processing chamber, where the reflected light passes through the upper window and through the opening in the coil connection enclosure and through the opening in the metrology enclosure. A tip angle and a tilt angle of the optical collimator are remotely adjusted to optimize an orientation of the optical collimator.