Analytical Sciences

Parallel-Plate Wet Denuder Coupled Ion Chromatograph for Near-Real-Time Detection of Trace Acidic Gases in Clean Room Air

Masaki TAKEUCHI,* Hiromichi TSUNODA,** Hideji TANAKA,* and Yoshimi SHIRAMIZU***

*Institute of Health Biosciences, The University of Tokushima Graduate School, 1-78-1 Shomachi, Tokushima 770-8505, Japan
**Graduate School of Pharmaceutical Sciences, The University of Tokushima, 1-78-1 Shomachi, Tokushima 770-8505, Japan
***Process Module & Integration Engineering Department, Renesas Electronics Co., 1120 Shimokuzawa, Chuou, Sagamihara 252-5298, Japan

This paper describes the performance of our automated acidic (CH₃COOH, HCOOH, HCl, HNO₂, SO₂, and HNO₃) gases monitor utilizing a parallel-plate wet denuder (PPWD). The PPWD quantitatively collects gaseous contaminants at a high sample flow rate (∼8 dm³ min⁻¹) compared to the conventional methods used in a clean room. Rapid response to any variability in the sample concentration enables near-real-time monitoring. In the developed monitor, the analyte collected with the PPWD is pumped into one of two preconcentration columns for 15 min, and determined by means of ion chromatography. While one preconcentration column is used for chromatographic separation, the other is used for loading the sample solution. The system allows continuous monitoring of the common acidic gases in an advanced semiconductor manufacturing clean room.

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