Measurements and Simulations of Particles in a Plasma Chemical Vapor Deposition Chamber

In a plasma chemical vapor deposition (CVD) chamber, particles generated during the deposition process adhere to the wafer after the process ends. Since it is important to remove particles efficiently in the discharge step after the deposition process, we determined the optimal conditions by using particle motion simulation. The electrostatic force, ion drag force, and gas drag force produced by neutrals, which particles receive in plasma, are calculated from plasma and gas flow simulations. The particles vibrate in response to the downward ion drag force and the upward electrostatic force, while moving to the wafer edge due to the gas flow. In the discharge step, the baseline condition and another condition (the side power condition) where the electric field is perpendicular to the wafer were compared using 50 particles set at random positions. The number of remaining particles was 15.0 under the baseline condition and 2.8 under the side power condition. In the experimental results corresponding to both conditions, the number was found to be reduced to 23.3% by adjusting the conditions. The simulation results are in good agreement with the experimental results.