SEMI Clarifies PFAS Regulations and Industry Standards

As global attention increasingly focuses on per- and polyfluoroalkyl substances (PFAS), industries face growing challenges in understanding complex regulatory requirements, concentration thresholds, and varying definitions. This comprehensive analysis provides clarity on these critical issues.

PFAS regulations are evolving at an unprecedented pace, ranging from complete bans to strict concentration limits. Regulatory approaches vary significantly across jurisdictions, particularly regarding the "Concentration of Regulatory Interest" (CRI). Some regulations prohibit intentional addition of PFAS, while others establish specific numerical thresholds.

The European REACH regulation's proposed PFAS restrictions illustrate these variations:

• Single PFAS limit: No single PFAS substance may exceed 25 ppb (measured through targeted analysis, excluding polymeric PFAS).
• Total PFAS limit: Combined PFAS concentrations (optionally measured after precursor degradation) must not exceed 250 ppb (excluding polymeric PFAS).
• Total fluoride threshold: Manufacturers must provide documentation proving PFAS or non-PAS fluoride content when total fluoride exceeds 50 ppm.

Critical to understanding these thresholds is recognizing how "concentration" calculation bases differ regionally. Europe's "article" definition follows a 2015 European Court principle treating commercially distributed components as separate articles. In contrast, the U.S. EPA defines articles as complete marketed products.

Despite increasing regulatory scrutiny, PFAS definitions remain inconsistent across jurisdictions, creating additional compliance challenges. Representative definitions include:

• EU REACH proposal: Substances containing at least one fully fluorinated methyl (CF3-) or methylene (-CF2-) carbon atom (without H/Cl/Br/I attachment).
• U.S. EPA reporting rule: Chemicals containing R-(CF2)-C(F)(R′)R″ units where CF2/CF are saturated carbons and R/R′/R″≠H.
• Maine/New York regulations: Any organic fluorochemical containing at least one fully fluorinated carbon atom.

Notably, some regulations apply only to specific PFAS lists, like the U.S. TSCA's SNUR for long-chain perfluoroalkyl carboxylates and sulfonates.

SEMI and the Semiconductor Industry Association (SIA) have adopted an inclusive PFAS definition covering all chemicals containing -CF2- and/or -CF3 molecular units. This approach reflects the industry's commitment to comprehensive risk management and sustainable development.

The PFAS family is far larger than commonly recognized. The U.S. EPA maintains a "List of Lists" database containing over 12,000 unique PFAS substances, suggesting actual PFAS applications may involve even broader ranges than current regulations address.

Accurate PFAS management requires understanding fluoropolymer naming conventions, as many industrial materials use trade names rather than chemical designations. Common fluoropolymers (all PFAS) include:

• ECTFE (Ethylene Chloro Tri Fluoro Ethylene)
• ETFE (Ethylene Tetra Fluoro Ethylene)
• FEP (Fluorinated Ethylene Propylene)
• PCTFE/PTFCE (Poly ChloroTri Fluoro Ethylene)
• PFA (Per Fluoroalkoxy Alkane)
• PTFE (Poly Tetra Fluoro Ethylene)
• PVDF (Poly Vinylidene Fluoride)
• PVF (Polyvinyl fluoride)

Fluoroelastomers (FKM/FPM) and perfluoroelastomers (FFKM/FFPM) lack specific CAS numbers, with compositions varying by manufacturer. The proliferation of trade names for licensed fluoropolymer products further complicates material identification.