Introduction
Starting July 4, 2022, PFOA (Perfluorooctanoic acid) levels in semiconductor manufacturing and related equipment (SMRE), including replacement parts, entering the European Union (EU) will be restricted to 25 ppb per component (or any part thereof). Semiconductor equipment components (and the parts thereof) of particular concern include fluid tubing and fittings, pipe/seal tape, wire and cable insulation, filters, valves, tanks, panels, reaction vessels and o-rings; if they are made from fluoropolymers or fluoroelastomers.
When PFOA is used as an aid to the manufacture fluoropolymers such as PTFE, PFA, PVDF or fluoroelastomers such as FKM and FFKM (collectively referred to as fluoromaterials), an unintended PFOA residue can be trapped within the fluoromaterial. Buyers of components used in SMRE are usually unaware of the processing method used for any fluoromaterials they may contain, and, as a consequence, the potential for PFOA residue. This lack of information about potential PFOA residues could result in regulatory enforcement actions and restricted market access, particularly in the EU.
The impact of restrictions on fluoromaterials used in SMRE has been introduced in previous SEMI articles ‘Fluorinated Compound Restrictions May Trigger Costly Equipment Changes’ and ‘Fluorinated Substance Restrictions Triggers Costly Equipment Changes.’
PFOA and its related compounds, such as the ammonium salt APFO (collectively called PFOA in this article), are recognized internationally as hazardous chemicals and are now targeted for regulatory restriction in the U.S., Taiwan, Canada and the EU. The UN Stockholm Convention on Persistent Organic Pollutants (POPs) is also considering listing PFOA, which could lead to additional international restrictions.
The SEMI EHS Division PFOA Compliance Working Group has been working to understand:
- The likelihood of PFOA residue entering the supply chain of new components
- The residual level of PFOA in fluoromaterials produced prior to the phase out of PFOA by some manufacturers
- The impact of PFOA residue on the secondary equipment market
This SEMI resource page, ‘Elimination of PFOA from the Equipment Supply Chain,’ and the supporting FAQ contain the Working Group’s key findings and conclusions.
PFOA in the Fluoromaterial Supply Chain
Signatories to the U.S. EPA Stewardship Program, which include FluoroCouncil members, eliminated PFOA from their manufacturing processes by 2013. However, other fluoromaterial manufactures – particularly in China, Russia and India – might still use PFOA and pose a significant risk to the worldwide supply chain.
China, the world’s largest fluoromaterial producer, accounts for 53 percent of global production of PTFE and 38 percent of worldwide production of PVDF, FEP and FKM. An estimated 75 percent to 85 percent of fluoromaterials are manufactured using PFOA in China. Fully 25 percent of these fluoromaterials are exported, primarily to the U.S, Japan, EU and India. What’s more, finished goods made from or containing fluoromaterials that might be used as components in SMRE are exported from China.
Documentation that traces fluoromaterials through the supply chain back to the original fluoromaterial manufacturer is key to meeting the PFOA regulatory requirements. This traceability can be straightforward in cases when an SMRE manufacturer directly specifies the use of a fluoromaterial in a custom-fabricated fluoromaterial component. However, for off-the-shelf components (e.g., cable ties, wiring insulation, tubing) or the components assembled from these components (e.g., controllers), the complexity and dynamics of the supply chain makes traceability back to the original fluoromaterial producer almost impossible.
Residual PFOA Levels
If, or how much, PFOA/APFO residue is contained in a fluoromaterial depends on the manufacturing process. Details of the manufacturing processes are proprietary and vary widely. Post manufacturing thermal treatments, such as sintering, extrusion, and molding, can result in the rapid thermal decomposition of APFO above 250C, but PFOA is significantly more stable. The temperature and time of thermal treatments is also proprietary and varies depending on the type of fluoromaterial and what is being made.
This variability makes it impossible to estimate the likely level of trapped PFOA or APFO in a finished component or a part thereof. It is unwise to use data on the level of residue made known for one case to extrapolate the level of residue across the fluoromaterial industry. However, an industry-wide range on the order of 1ppm-10ppm (nearly 1000 times the EU limit) is suspected. Testing for the presence of PFOA/APFO at 25ppb in components is also problematic as there is no standard test method, and results among the custom methods developed in each test lab may vary.
Given this uncertainty in test methods, a system of supplier declarations warrants consideration.
Impact on Secondary (Used) Equipment
The EU REACH restrictions apply to SMRE and replacement parts placed on the market at any time (not just initial placement – known as “first placing on the market”). For fluoromaterial components manufactured prior to 2013, there is a higher likelihood of residual PFOA/APFO levels exceeding the 25ppb limit of EU REACH. In principle all the SMRE components containing fluoromaterials should be investigated, and those containing PFOA above 25ppb must be replaced before the SMRE can be legally placed again on the EU market. Companies (e.g., semiconductor manufacturers) in the EU who wish to sell used equipment within the EU will be required to demonstrate the used equipment is in compliance. Selling older used equipment would likely be unprofitable after necessary investigations and component replacements are completed.
Next Steps
While the EU semiconductor manufacturing industry heavily depends on the secondary (used) equipment market, EU regulators may be unaware of the PFOA restriction’s damaging impact to this market. The EHS Division PFOA Working Group, in conjunction with SEMI Europe, is now considering how to bring this concern to the attention of regulators and to collaborate and lobby for effective changes including possible modifications to the EU Persistent Organic Pollutants (POPs) regulation.