Part per billion concentrations of acid gases such as SO x and NO x have been detected in both high purity gases and CDA lines. These contaminants can have deleterious effects on a number of high purity applications such as the optics found in lithography equipment steppers, scanners, and inspection tools. In addition, acidic gases have also been shown to reduce the life of masks and reticles, decrease fuel cell output due to catalyst poisoning, and cause hard disk drive crashes due to surface contamination and corrosion. Consequently, acid gas control in these applications has become a critical part of the required filtration system. SO x concentrations are typically used as the baseline for acid gas filter exposure guidelines and performance testing. However, this approach has been shown to provide poor filter life predictions, which has been attributed to the presence of other acidic and organic contaminants that compete with SO x for the available adsorption sites. Equally important, the type of sorbents and methods used to control acid gases can significantly affect the ability to remove SO x . In this work we will compare the performance of various sorbents, structures, and methods for the removal of SO x and NO x .

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Perfluoroalkylamine (PFAA) contamination has been observed to be a growing contamination issue in semiconductor fabs due to the increased tolerances demanded by next generation lithography processes. These contaminants are found within the cleanroom, process environments and within various tools and enclosures. As a result, effective control of PFAAs in lithographic processing and other critical environments are becoming an important filtration problem. This work was undertaken to evaluate filter performance for the removal of PFAAs and to provide an optimal filtration solution. The filter breakthrough performance of perfluorotributylamine (PFTBA), a common heat transfer fluid, is investigated over a range of environmental conditions for several commercially available adsorbent materials. The results from these accelerated tests indicate that PFAAs can be effectively removed with activated carbon-based chemical filters.

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