Special gases, such as ammonia, hydrogen chloride, and hydrogen fluoride, are widely used in semiconductor processing. On line monitoring the particulate contamination of the delivered gases is an important challenge. Impinger is a commonly used collector to trap and pre-concentrate the particulates from the cylinder and then to analyze it with ICP-MS. However, collection efficiencies were found to be less than 20% for particles with a diameter less than micrometer. Moreover, gases such as NH3 would dissolved in sampling water and become a saturated NH4OH solution which can extinguish the plasma immediately during analysis with ICP-MS.
The technique of single particles inductively coupled plasma mass spectrometry (spICP-MS) was recently applied to particle analysis and numerous studies have established a set of metrological criteria of spICP-MS for sizing or quantifying various types of nanoparticles. In this study, spICP-MS was used to directly analyze metallic particulate from cylinder gas. To prevent the plasma quenching, a gas exchange device (GED) was applied to remove the gas matrix. After the gas exchange was optimized efficiency, the composition of particulate impurity from ammonia gas was investigated. The detection limit of this method is at least 100-fold lower than the conventional impinger method, and could be applied to online monitoring of the particulate contaminants from the delivered gases without much consumption of cylinder gas.
 Spanne, M., Grzybowski, P and Bohgard, Mats American Industrial Hygiene Association Journal 1999, 60, 540-544.  Ohata, M., Nishiguchi, K. and Utani, K. Bunseki Kagaku 2013, 62 , 785−791.
Gas concertation analysis, dynamic gas concentration generation, the performance testing of gas analysis.
Job qualifications(5 years)
The Principal of Cylinder Gas Concentration Measurement System
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