SUPERCRITICAL AND SUBCRITICAL CO2 PROCESSING Sandia National Laboratories possesses extensive expertise in supercritical/subcritical carbon dioxide (SCCO2) processing applied to materials and process development. SCCO2 possesses liquid-like densities and solvating properties, has been demonstrated as a good solvent for non-polar organic compounds, and exhibits gas-like transport properties of viscosity and diffusivity along with negligible surface tension similar to a gas. This combination of properties allows the supercriticial fluid to access very small, complicated geometries to dissolve and remove organic contaminants. Sandia has extraction vessels of 1 to 20 liters and supercritical fluid chromatograph/extraction device and optical view cell for the study of solubility and phase phenomena in supercritical fluids. Important applications include: Particulate free cleaning process for the semiconductor industry. Elimination of stiction through the employment of non-aqueous processing/cleaning solutions. Micromachined polysilicon microelectromechanical device processing. Potential Benefits Elimination of surface tension effects and subsequent sticking of polysilicon structures to the silicon wafer substrate when using conventional air-drying. Can readily access ~1-3 micron spaces between microstructures. Substitution of supercritical CO2 for toxic or ozone depleting cleaning solvents in extraction, cleaning and other applications. Reduction in hazardous waste disposal associated with the above. Demonstrated Achievements Successfully applied supercritical CO2 extraction technology for the extraction of capillary fluids from polysilicon micromechanical devices in SNL Class 1 Microelectronic Development Facility. Contributed to the development of "Superscrub" line of supercritical CO2 extraction product sold by Autoclave Engineers. Designed Supercritical CO2 recyclable cleaning facility at a large government contractor under a joint DOE, DoD/USAF program Follow-up This proprietary Sandia capability may be applied to solve challenging problems in the field of polymer and other organic sciences. Sandia has the flexibility to form specific teams of technical experts from any or all of the above capabilities to focus expertise on specific technical challenges. We are interested in making this technology available to companies responsive to partnering with Sandia to develop near/term and/or future applications via licensing or cooperative development agreements. For further information, please respond by mail or fax to Joanne Trujillo no later than December 15, 1998 at: Sandia National Laboratories, MS 1380, P. O. Box 5800, Albuquerque, New Mexico 87185-1380. Fax: (505) 843-4163. Please indicate the date and title of this CBD notice. E-MAIL: Joanne Trujillo, jmtruji@sandia.gov. Posted 12/01/98 (W-SN275652).

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