A model was developed to estimate particle contamination probabilities on inverse surfaces at low pressure for inertial and diffusional particle deposition under the influence of gravity, drag, and thermophoresis. The model shows that contamination probabilities strongly depend on particle size, initial velocity, and initial distance between particle and surface. While thermophoresis effectively protects the surface against deposition of particles with 10 mm (or more) initial distance and velocities below 1 ms, the contamination probability of particles with an initial distance of 0.1 mm is very high for small particles due to their high diffusivity and for fast particles due to inertia.
Bibliographical noteFunding Information:
This work was supported by the Deutsche Forschungsgemeinschaft (DFG) under Grant No. AS291/1-1. The authors also wish to thank Jung Hyeun Kim of the University of Seoul and Se-Jin Yook of Hanyang University for their collaboration on the inertia model as well as Burkhard Stahlmecke of IUTA, Dan Rader, John Torczynski, and Michail Gallis of Sandia National Laboratory, and Kevin Orvek of Sematech for fruitful technical interactions.