Progress on the Physical Approach to Molecular Contamination Modeling

A review of the contamination physics and of the most widespread engineering approaches to contamination assessmentwas carried out. The twomain approaches are the physical and the empirical one. Themain questions still open to validate the physical approach to outgassing and deposit physics were then studied. Among others, special attention was paid to the important point of a realistic separation of chemical species, probably a prerequisite for a physicalmodeling. Several original results were obtained. Some lead to a quite clear conclusion, like the preeminence of the limitation by desorption over the limitation by diffusion for outgassing. This observed trend needs yet to be validated on other materials. Other major results are progress on the validation of the physical approach and on the ambitious species separation program.