Optical emission studies and neutral stream characterization of a surface reflection materials processing source

• Published in: Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films Vol. 18; no. 4; pp. 1359 - 1365
• Main Authors: Tang, Xianmin, Manos, Dennis M.
• Format: Conference Proceeding Journal Article
• Language: English
• Published: 01-07-2000
• Subjects: Argon; Composition effects; Emission spectroscopy; Fluorocarbons; Light emission; Mathematical models; Oxygen; Pressure effects
• ISSN: 0734-2101; 1520-8559
• DOI: 10.1116/1.582354

We report optical emission studies of the plasma source and measurements using heat flux and momentum analyzers of the fast neutral flux and energy in a low-energy surface-reflection neutral source. Both optical emission and Langmuir probe studies indicate a mode transition from a capacitively coupled mode to an inductively coupled mode as the rf power is increased. Spectroscopic actinometry shows that the atomic species resulting from molecular dissociation increase with increasing rf power. Changing the reflector bias changes the neutral energy without changing the discharge composition. The measured heat flux and momentum carried by the fast neutrals are used to derive the flux-weighted average velocity and the particle flux of the neutral stream. The measured neutral stream energy is found to be 4–6 eV. The neutral flux increases with the rf power. The measured neutral energy increases less than linearly with the reflector bias. This might be caused by the decreasing reflection efficiency of the reflector plate or a large collisional loss as the neutrals traverse the process region. The etch rates and cleaning rates calculated from the measured neutral flux and previously reported measured ashing and cleaning rates are in good agreement.