Particle Deposition on Semiconductor Wafers

Abstract

The deposition of aerosol particles on semiconductor wafers in the typical manufacturing environment of the clean room has been calculated using the equations of convective diffusion and sedimentation. The result shows that the deposition velocity decreases with increasing particle size in the diffusion regime and increases with increasing particle size in the sedimentation regime, with a minimum deposition velocity occurring in the vicinity of 0.2 μm. The minimum deposition velocity varies from approximately 0.2 × 10⁻³ to 0.7 × 10⁻³ cm/s, depending on the size of the wafer, the airflow velocity, and whether the wafer is freestanding or placed on top of a workbench.