Using a Semiconductor AMC Analyzer to Measure Material PFAS Off-Gassing

There are a wide variety of airborne molecular contaminants (AMCs) that require systematic monitoring during the manufacture of semiconductors; per- and poly-fluoroalkyl substances (PFAS) stand out among these and are garnering increased interest due to their destructive impact on the environment and on human health.

The production of PFAS is closely linked to material off-gassing and occasionally with production processes as secondary products. Due to both the importance of high-quality chip production and the increasing concerns regarding PFAS, finding efficient ways to understand and alleviate these emissions in this area is essential.

The extremely sensitive and versatile TOFWERK Semicon AMC Solutions provide state-of-the-art technology to measure the emissions of dozens of compounds simultaneously in real-time, without the need for sampling preparation, and with extraordinary precision.

A single AMC monitor is able to provide detailed information about airborne PFAS emissions even at parts-per-trillion (ppt) concentrations and give users unparalleled insight into the sources and abatement of such compounds.

Experiment

In order to measure the capabilities of the AMC Solutions device for PFAS measurement, sample resins which are commonly used in semiconductor manufacturing materials were heated in a temperature-controlled oven, as shown in Figure 1. The oven emissions were then measured by an AMC Analyzer.

Figure 1. Experimental setup used in this study. Image Credit: TOFWERK

PFAS Off-Gassing

Figure 2 displays example PFAS emissions measured from two different resin samples. While the temperature increases incrementally from around 100 °C up to 250 °C, the PFAS off-gassing emissions also generally increase.

Nine different species of PFAS, measured concurrently, were detected at concentrations ranging from less than one to around one ppt.

Figure 2. The 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 contemporary soft chemical ionization of the AMC Analyzer means that a user is able to confidently identify a wide range of PFAS simultaneously and without fragmentation, a common issue among higher-energy ionization techniques.

Figure 3 plots the mass defect of 24 molecules against their molecular mass (molecule combined with the reagent ion, I^–).¹ The dashed lines demonstrate the addition of either O (blue) or CF₂ (red) to the parent molecule, offering a direct insight into the formation of PFAS and associated molecules.

Figure 3. Complete PFAS observed from resin sample plotted as a log of the observed signal by mass to charge and mass defect. Image Credit: TOFWERK

Conclusion

Due to its soft ionization, speed and exceptional sensitivity, the TOFWERK Semicon AMC Analyzer is ideal when it comes to the reliable and efficient measurement of PFAS emissions.

The portable and compact instrument is able to detect and identify scores of PFAS molecules in mere seconds and provides a vital first step in understanding these important chemicals, helping protect the environment and pioneering a sustainable future in one of the world’s most important industries.

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

1. 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.

For more information on this source, please visit TOFWERK.