Per- and polyfluoroalkyl substances (PFAS) are one of the many airborne molecular contaminants (AMCs) that require systematic monitoring during semiconductor manufacturing processes. In recent years, they have attracted particular interest as a result of their detrimental impact on human health and the environment.
The production of PFAS in the semiconductor industry is related to material off-gassing, and in some cases with production processes as secondary products. Due to the importance of high-quality chip production and the growing concern surrounding PFAS, the development of efficient methods to understand and mitigate emissions in semiconductor manufacturing is crucial.
The TOFWERK Semicon AMC Solutions is extremely sensitive and versatile and offers state-of-the-art technology to measure the emissions of dozens of compounds in real-time, simultaneously, with exceptional precision and without sampling preparation.
A single AMC monitor or analyzer delivers a wide range of information about airborne PFAS emissions, even at parts-per-trillion (ppt) concentrations, enabling users to gain unprecedented insight into the sources and abatement of these compounds.
Experimental Setup for PFAS Off-Gassing
To determine the proficiency of the AMC Solutions for PFAS measurement, sample resins frequently used in semiconductor manufacturing materials were heated in a temperature-controlled oven, as shown in Figure 1. Oven emissions were then measured by an AMC Analyzer, one of two Semicon AMC Solutions offered by TOFWERK.
Figure 1. Experimental setup used in this study. Image Credit: TOFWERK
PFAS Off-Gassing from Resin Samples
Figure 2 presents examples of PFAS emissions measured from two different resin samples in the experiment.
As the temperature increases in four increments, from just over 100 °C to 250 °C, the PFAS off-gassing emissions generally rise. Nine different species of PFAS, all measured simultaneously, were detected at concentrations ranging from less than one pptv to approximately one ppbv.
Figure 2. Concentration of nine species of PFAS versus oven temperature with concentrations averaged to each oven temperature setpoint and data background subtracted from blank (empty oven) measurements. Image Credit: TOFWERK
The state-of-the-art soft chemical ionization used by the AMC Analyzer allows the user to identify a wide range of PFAS confidently and simultaneously and without fragmentation, which can be an issue in higher-energy ionization techniques.
Figure 3 displays plots of the mass defect of 24 molecules against their molecular mass (molecule combined with the reagent ion, in this case I-).[1] The dashed lines indicate the addition of either CF2 (red) or O (blue) to the parent molecule, providing insight into the formation of both PFAS and associated molecules.
Figure 3. Complete PFAS observed from resin sample plotted as log of the observed signal by mass to charge and mass defect. Image Credit: TOFWERK
Conclusion
Owing to its speed, soft ionization, and exceptional sensitivity, the Swiss-engineered TOFWERK Semicon AMC Analyzer is ideal for the efficient and reliable measurement of PFAS emissions.
A single compact, portable instrument is able to detect and identify dozens of PFAS molecules in seconds, providing a vital initial step in understanding these important chemicals, protecting the environment and ushering in a sustainable future in one of the most important industries in the world.
Acknowledgments
Produced from materials originally authored by Katie Schmidt, Felipe Lopez-Hilfiker, Priyanka Bansal, Carla Frege and Veronika Pospisilova from TOFWERK.
References and Further Reading
- Riedel, T. P., et al. (2019). Gas-Phase Detection of Fluorotelomer Alcohols and Other Oxygenated Per- and Polyfluoroalkyl Substances by Chemical Ionization Mass Spectrometry. Environmental Science & Technology Letters, 6(5), pp.289–293. https://doi.org/10.1021/acs.estlett.9b00196
This information has been sourced, reviewed and adapted from materials provided by TOFWERK.
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