Responding with a breakthrough approach to a major semiconductor customer request, DAS Environmental Expert GmbH of Dresden, Germany, developed and installed SALIX – the world’s first commercially available point-of-use system for removing waste gas pollutants in semiconductor wafer manufacturing wet bench applications. DAS believes its unique approach of using a high-efficiency, small footprint point-of-use system that lowers abatement cost opens new markets for cost-effective treatment of single-wafer wet bench exhaust gases. DAS Environmental Expert is a leading worldwide enterprise focused solely on waste abatement in semiconductor/ LED/PV/FPD manufacturing for clean air.
One SALIX system per wet bench is all that’s needed, and just one pipe for the cleaned exhaust. It offers a smaller footprint with no switching boxes needed, and is far more cost-effective and efficient than central scrubbers for treating processes that create water-soluble waste gases.
Reduced Cost, More Efficient Abatement
The single-wafer cleaning process widely used for cleaning 300-millimeter wafers in wet benches distributes cleaning agents onto rapidly spinning single wafers and spins them off at the edge where baffle plates within the system collect the water, acidic and alkaline chemicals, and volatile solvents; the process for cleaning 200-millimeter wafers immerses the entire cassette. With up to 12 stations per wet bench and exhaust from each chamber requiring several exhaust systems, the breakthrough DAS approach using SALIX eliminates the need for elaborate space-filling change-over modules to avoid deposition in the pipes. It is far more cost-effective and efficient at preventing clogging than the extremely elaborate extraction systems commonly used to separate and extract the acids, alkalines and solvents in the exhausts; these require separate suction to prevent particle buildup and condensation within the pipes.
In contrast, SALIX removes the harmful substances from the gas stream directly at their point of origin using a two-stage scrubber process of chemical and physical absorption, and can treat up to 3600 m3/h of raw gas. Separate inlets feed the harmful gases from the wet bench process chambers into a SALIX pre-scrubber that pre-cleans the gas using spray nozzles. Next the waste gases pass into the first scrubber stage and then a second stage that uses a different scrubbing liquid. The remaining clean gas then can be released safely into the air without any danger to the technology or the environment. Because the SALIX system does not require any air dilution, the clean air remains in the clean room, further reducing cost.