Fluorine-19 NMR Spectroscopy as a Strong Analytical Tool for the Development of PFAS Waste Management Strategies in Semiconductor Manufacturing

Abstract

Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent, mobile, and bioaccumulative compounds with demonstrated toxicity, often linked to endocrine disruption, liver damage, cancer, and developmental risks. Semiconductor manufacturing facilities or fabs rely on the use of PFAS in some of their equipment components and materials. Photolithography patterning performance is often enhanced by fluorinated photoacid generators in photoresists, low-index fluoropolymers in anti-reflective coatings, and fluorosurfactants. Since these materials are frequently released in fab waste, they inform the abatement and characterization needs evaluated in this review. In this article, we discuss 1D/2D NMR methods, quantitative NMR (qNMR), proper selection of solvents and internal standards, strategies for managing dilute samples in fabs, PFAS abatement techniques and 19F NMR implications, and integrated analytical methods for PFAS characterization. 19F NMR is a strong tool that can provide non-target and class-specific analysis, measure total organic fluorine, and, more importantly, allow for rapid screening of waste streams before and after treatment, thereby providing fab-specific guidance on PFAS treatment techniques and ultimately assisting with the long-term aspiration of phasing out PFAS-containing materials. Such capabilities make 19F NMR a valuable metrology tool for PFAS detection, quantification, and sustainable waste management in fabs. Furthermore, novel 19F NMR methods with enhanced sensitivity can further decrease detection limits and allow for the characterization of highly dilute samples, often pertaining to fab waste.