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7. CWC 791: Liquids with pH_<2 <br />Site _ <br />2010 Quantity (lb)2014 <br />quantity (lb) <br />LLNL <br />150 6117 <br />7.1 EtchinFM oaerations <br />Engineering's Micro Nano Technology Center (N1T1TC) generates extremely hazardous <br />aqueous wastes (CWC 791) from micro fabrication processes. Etchant solutions are <br />applied to remove metals and silicon oxide/silicon nitrides as a preparation step prior to <br />applying additional materials to the top of silicon wafers. After surface preparation, <br />substrates are rinsed with water. This is a non -hazardous categorical process, the <br />wastewater is collected in a retention tank and is sampled and analyzed before it is <br />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. MNTC have been <br />replacing wet chemical etching and cleaning with plasma etching because it is more <br />controllable and safer, and also produces less hazardous waste. <br />September 1, 2015 SB 14 Report 1V_7 <br />