Plasma deposition reactors are regularly subjected to non-value added cleaning to remove the build-up of oxide material. If the chamber cleaning step can be made as fast as possible, the downtime for the tool can be minimized. It is therefore desirable to determine the optimum chamber cleaning chemistry. To do this, we need to know the plasma chemistry dynamics and the influence of reactor geometry and process parameters. The FLUENT/PLASMATOR joint product can be used to study this. FLUENT/PLASMATOR provides an accurate method for fast 3D plasma discharge simulations.

Applied Materials P5000 Reactor

Flow patterns and electron density. Flow rate is 900 sccm C4F8 and O2 (80% 02). The operating pressure is 2 Torr.

FLUENT/PLASMATOR calculates the production of CxFy radicals (such as CF2 shown above).

FLUENT/PLASMATOR calculates the production of free fluorine. The primary clean gas, F, is generated and consumed near the electrodes. The concentration of atomic fluorine is high near the periphery of the electrodes.

Plot of cleaning rate throughout the P5000 reactor. The clean rates mirrors atomic fluorine distribution. Higher clean rates are found near the periphery of the electrodes where the atomic fluorine concentration is highest.

The model was then used to quantify how the clean rate increases with pressure, as shown below. The simulation results also identified areas of high and low clean rates, and their dependence on process parameters.