Quantitative Modelling of Residual Molecular Contamination in Low-Pressure Processing Environments

Some published experimental results of organic molecule contamination in vacuum processing are reviewed. The build-up of gaseous contamination from the residual gas in vacuum ambient to the surface of a substrate is quantitatively modelled. Calculations show that the build up of contaminants from the residual gas phase to the surface is very fast, essentially because in very dilute gas there are little molecular collisions to slow down the transport towards the substrate.