Particle Redeposition - Once a particle is removed from the surface, the set up and system design must insure that it is swept away and cannot redeposit on the cleaned surface. Generally, high flows, or laminar flow, along with nitrogen purges, are used. These flow are passed over the surface while cleaning and assist in particle removal away from the surface. Filters and other options are needed. For table top systems, just insure the stream can flow away from teh cleaning area without striking other objects.
Material selection is important.
The material choice and surface finish must be specified. Cleaning fixtures and other items within the cleaning region is suggested. Cleaning Method - The cleaning process, after removing particles and organic residues, must not allows for these particles to land back on the part that was cleaned. In other words, a particle removed from the surface by CO2 can not land back on the surface of the clean part. CO2 Purity - This was investigated separately in two studies.