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CWC 791: Liquids with pHA <br />Site 2010 uantit lb) <br />LLNL I 50 <br />7.1 Silicone Wafer Etching and Cleaning <br />Site 2010 quir tit Ib <br />LLNL 50 <br />Raw Materials: Micro Fabrication Product: <br />at <br />chant parts surface Finished <br />preparation and substrates. <br />cleaning. <br />CWC 791 Ofl-site disposal. <br />Acidic <br />Solution. <br />Rinse Flows to Discharge to <br />Retention Tanks. Sewer. <br />FIGUREIV.6.1. 8153 SILICON WAFER ETCHING AND CLEANING WASTE <br />GENERATION PROCESS <br />Engineering's Micro Nano Technology Center (MNTC) generates extremely hazardous <br />aqueous wastes (CWC 791) from micro fabrication processes. Etchant solutions are <br />applied as a preparation step prior to applying additional materials to the top of silicon <br />wafers. After surface preparation, substrates are rinsed with water. This is a non- <br />hazardous categorical process, the wastewater is collected in a retention tank and is <br />sampled and analyzed before it is approved for release to sanitary sewer. <br />MNTC continues to optimize their processes through a number of activities such as <br />chemical reuse and experimentation with less toxic alternatives. <br />SOURCE REDUCTION/POLLUTION PREVENTION EVALUATION <br />Description of Measure: <br />LLNL plans to continue existing best management practices to minimize this waste <br />stream. No other source reduction measures are planned at this point. <br />September 1, 2011 SB 14 Plan <br />74 <br />Note: 37 lbs of spent etchant CWC 791 was generated during 2010 from research and <br />development activities associated with optics proof -of -concept research in B490. No <br />CWC 791 waste was generated during 2007, 2008 or 2009. This waste stream has <br />not been included as it fits within the exempted category: "Waste generated from <br />laboratory scale research". <br />September 1, 2011 SB 14 Plan <br />75 <br />