PFAS in Semiconductor Manufacturing

The PFAS Problem

Per- and polyfluoroalkyl substances (PFAS), are a group of man-made ‘forever chemicals’ widely used since the 1940s in products such as non-stick cookware, cosmetics, and food packaging due to their resistance to grease, water, heat, and oil.

Their strong chemical bonds make them extremely persistent, with 97% of the U.S. population having PFAS in their blood. PFAS have been linked to multiple health issues, including cancer, immune system disruption, thyroid disease, and liver and kidney damage.

PFAS in Semiconductor Manufacturing

Semiconductors, or microchips, are essential components in electronics like cell phones, computers, and medical diagnostic equipment (SIA).

The semiconductor industry, a leader in global R&D and manufacturing, has long relied on high-performance per-and polyfluoroalkyl substances (PFAS) additives, particularly in antireflective and photoresist coatings, for advanced chip production.

Source: Statista, SEMI

Source: U.S. Semiconductor Ecosystem Map - SIA

Regulations Drive PFAS Solutions for Chipmakers

In 2024, the U.S. Environmental Protection Agency (EPA) established the first national, legally enforceable drinking water standards for PFAS to protect communities from exposure. The EPA set Maximum Contaminant Levels (MCLs) at 4 parts per trillion for PFOA and PFOS, and 10 parts per trillion for PFNA, PFHxS, and GenX chemicals. PFOA and PFOS have also been classified as hazardous substances under CERCLA.

Emerging PFAS regulations have led many semiconductor fabrication companies to proactively seek PFAS destruction solutions, driven by the future liability associated with PFAS-contaminated effluent wastewater. Semiconductor manufacturers have also explored PFAS alternatives with little success, instead turning to short-chain (4 carbon atoms or fewer) PFAS compounds which pose similar toxicological risks based on recent studies.

As the regulatory framework for PFAS becomes more stringent, it is increasingly important for fabrication producers to explore PFAS treatment solutions that are available now.

Hydrothermal Alkaline Treatment (HALT)

Aquagga’s HALT technology combines temperature, pressure, and an alkaline amendment to effectively break the strong carbon-fluorine bonds that hold PFAS together, achieving complete mineralization.

Technical Advantages

Complete PFAS Destruction

HALT is unique in its ability to completely destroy all types of PFAS (long, short, and ultra-short-chain PFAS) with over 99% destruction efficiency.

Concentrated Waste Disposal

Characterized by the EPA as a “heavy lifting” treatment technology, HALT is useful for treating concentrated wastes.

Complex Matrix Compatibility

HALT can destroy PFAS in complex liquid matrices with high total organic carbon (TOC), high total dissolved solids (TDS), and high turbidity. HALT can effectively treat high salinity wastewater, which is a challenge for other destruction technologies.

Tunable Process

HALT is highly tunable to the type(s) of PFAS needing destruction, so that milder temperatures and chemical loadings can be used to destroy perfluorocarboxylic acids and fluorotelomer compounds.

Integrating HALT for On-Site PFAS Destruction

Front end production involves wafer fabrication, using processes like photolithography and etching to create circuit patterns on silicon wafers. These processes generate wastewater and byproducts that contain PFAS.
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Back end production focuses on assembling and packaging semiconductor chips. Additional waste streams are created, including those that may contain PFAS from packaging (moldings and mountings) and testing materials.

When treating PFAS, the recommended approach involves separation, concentration, and destruction. Aquagga’s HALT technology interfaces with separation and concentration technologies such as reverse osmosis (RO), regenerable ion-exchange resin (IXR), and foam fractionation to treat high-concentration secondary waste streams.

As a final step in the PFAS treatment process, the HALT system then intakes this PFAS-rich feedstock for complete destruction, resulting in clean water without any unwanted byproducts. HALT can be integrated for both front and back end fabrication.

HALT Value-Adds

Modular units that can seamlessly integrate into existing semiconductor facilities without disrupting production.

Closed-loop PFAS disposal solution without reintroducing contaminants.

Compact footprint, highly scalable, and energy efficient.

Remote control and monitoring support continuous operation and real-time optimization.

Compliance with discharge requirements and reduction in future liability.

Fab Wastewater Collection Strategies

Decentralized (Segregated) Approach

Aquagga’s PFAS destruction technology is ideally suited for a segregated collection strategy, ensuring focused containment and specialized treatment. Wastewater should be treated close to its source, where flows are typically lower and concentrations higher.

Benefits of this collection approach include cost, scalability with regulations, and focused treatment strategy. This approach optimizes opportunities for comprehensive wastewater collection across both semiconductor front end and back end production stages.

Centralized (End-of-Pipe) Approach

Centralized collection is an “end-of-pipe” approach that treats large volumes of less concentrated fabrication wastewater.

This method is generally less effective because it doesn’t address PFAS contamination at its source. As a result, waste streams can become more complex and may contain a broader range of PFAS species, making them more challenging to treat.