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DR. STEVE ALLEN AND DR. MICHAEL R. HAHN, Microbar Incorporated, Sunnyvale, CA, USA

ABSTRACT

Modern semiconductor fabs are highly dependent upon a continuous flow of ultra-pure water for normal operations. Large fabs measure their water usage in millions of gallons per day. The cost of producing this water, both in capital expenditures and community goodwill, is continually rising as world-wide fab capacity is expanded. Most of the current water consumption is for processes such as CMP, wet etch, wafer cleaning and back grind. The wide disparities in pH, dissolved and suspended solids content, and metallic contamination present major challenges for facilities trying to treat wastewater. The solution to these technical challenges, as well as the associated public goodwill dilemma, is to reprocess the water to allow either recycling within the same processes or reuse in another process in the facility. A technology has been developed to address the difficult problems created by CMP and copper plating as well as fluoride removal. Contamination can be safely and efficiently removed from wastewater using specially engineered polymers and membrane technology. This technology has been used to successfully remove silica and fluorides from semiconductor wastewater streams and metallic contamination, such as copper, arsenic and cadmium, in diverse applications in the mining and electronics industries. Using this new treatment technology, semiconductor fabs can reduce operating costs, comply with expanding environmental regulation and improve relations within the local community.