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SYPT: Symposium Plasmatechnik für die Optikherstellung

SYPT 2: Plasmatechnik

SYPT 2.5: Hauptvortrag

Montag, 8. März 2010, 18:30–19:00, E 415

Plasma Diagnostics for Plasma Process Instabilities through Gas Heating — •Michael Klick — Plasmetrex GmbH, Berlin, Germany

Beyond sputtering, plasma etching and deposition are major processes for optical layers. Here heating of process gas by ions in the boundary sheath is one of major issues in industrial plasma processing. The gas temperature can reach more than 1000 K in real plasma processes. The increasing gas temperature decreases the gas density and affects plasma process and product properties.

Plasma diagnostics can help to control these effects. Many plasma diagnostic approaches use moments of the electron energy distribution function; the excitations rates of species for optical emission spectroscopy (OES) and the collision rate for Self Excited Electron Spectroscopy (SEERS) as an electrodynamic method. SEERS is based a nonlinear plasma model for harmonics in the discharge current in case of capacitive coupling. By fitting the model to the experiment, it provides a parameters estimation for plasma parameters as the electron collision rate.

The electron collision rate has the advantage to depend directly on the gas density so that one can conclude readily to gas temperature changes. The gas temperature, however, changes also chamber wall conditions in reactive plasmas. These complicated dependencies will be shown for plasma etching and deposition in industrial manufacturing discussing also different sensitivities to and importance of the gas temperature.