Evaluation of 3 Commercially Available, On-Line TOC Analyzers for Monitoring Recycled Water in Semiconductor Processing

Rapid detection of excursions in the concentration of organic contaminants in water that is being recycled is crucial to the more widespread acceptance of rinse water recycling as a method of reducing water usage in semiconductor manufacturing. In 1995 SEMATECH'SS116 PTAB (Project Technical Advisory Board) arbitrarily targeted a response time of 30s as the goal for the on-line detection of TOC (Total Oxidizable Carbon) in water - a goal thought to simpliilj the design of water recycling systems (less volume required for water storage in the recycle loop) and lead to more widespread adoption of recycling of spent rinse waters by the US semiconductor industry. A subsequent evaluation of the TOC analyzers commercially available in early 1996 demonstrated that the fastest response times were on the order of three minutes ljllef. 1]. This paper updates the 1996 evaluation of commercially available TOC analyzers by assessing modified versions of two of the previously evaluated analyzers and also anew analyzer that became commercially available in 1997.