CO2 Snow General Information CO2 snow cleaning uses "snow" particles formed from CO2 gas. The process is effective for particle removal. Some success has been reported in removing finger prints and flux residue. The exact removal mechanism is not completely understood. Some sources believe it is a weak blasting process in which the kinetic energy of the traveling snow flake removes particles. Other sources believe that there is a phase transition of the snow flake as it travels over a surface, which is actually removing the particle. CO2 snow cleaning is more suitable for the higher cleanliness levels. It may be a good option for particle removal, and possibly thin fluid removal, on delicate surfaces such as optical components and thin-film mirrors. The equipment required is fairly simple: A source of CO2 gas A gas purifier (optional) A proprietary "snow" gun. The "snow" gun can be mounted in a controller for automated processes. One version has been designed to clean small (less than 0.25-inch diameter) blind holes. Welding grade CO2 can be used if it is processed through a purifier. This process can introduce a certain amount of contaminant, depending on the purity of the CO2 gas. This is usually not a problem except for the highest semiconductor cleanliness levels. State Information | Glossary | Conversion Checklist | Comments Home | Process Advisor | Alternatives | Links | Search All SAGE material, Copyright© 1992, Research Triangle Institute Last Update: 18 March 1995 sage@rti.org http://clean.rti.org/alt.cfm?id=sn&cat=gi