Evaluation of a Wafer Fab AMC Monitoring and Control Program

An air monitoring program is in place at a wafer fab to characterize outdoor air quality and its potential impact on manufacturing processes. Airborne molecular contamination (AMC), and specifically acid contamination, was of particular concern as the facility incorporated 90-nanometer (nm) manufacturing technology. Impinger ionic analysis, passive and real-time reactivity monitoring, and litmus paper hue readings were among the techniques used to assess air quality. Historical data for each monitoring technique was evaluated and compared to determine the applicability of each monitoring technique for these purposes. Data from this monitoring program also offered an opportunity to evaluate the performance of chemical filters installed in makeup air handling units for their ability to remove AMC. This study presents the results of air monitoring, detailing outdoor air quality and how that air quality compares to established specifications; comparison of different monitoring techniques used in the study; performance of installed chemical filter systems; recommendations for improving acid contamination control and evaluation of selected options; and recommendations for overall AMC monitoring and control programs.