Semiconductor industry announces phaseout of intentional uses of PFOA

World Semiconductor Council (WSC) announced last month that it successfully completed the phase-out of intentional uses of perfluorooctanoic acid (PFOA), its salts, and PFOA-related compounds in photolithography or etch processes.

Therefore, the WSC reported to the United Nations Stockholm Convention Persistent Organic Pollutants Review Committee (POP-RC) that, as of 2023, the semiconductor industry no longer has a need for exemptions from restrictions. “Intentional use” means a substance is used deliberately for a specific function or to achieve a specific characteristic.

This elimination is a major environmental management achievement for the worldwide semiconductor industry. The WSC has been working on managing and substituting these uses of PFOA for more than a decade, with a commitment in 2018 to phase out intentional uses of PFOA. Chipmakers worked with their suppliers over many years and invested significant resources and technical expertise to identify, qualify, and integrate alternative chemicals that met demanding performance requirements.

With respect to future policy and industry actions, the global semiconductor associations wrote to the UN POP-RC:

"As we have informed the Secretariat and the POP-RC previously, the semiconductor industry relies on chemicals (such as short-chain PFAS) that possess specific chemical and physical properties and functional attributes required to manufacture semiconductor devices. There currently are no known alternatives to many of these chemicals for use in our manufacturing processes. For this reason, replacing these chemicals may prove to be more difficult even than the PFOS and PFOA challenges.

"The industry has a demonstrated record of responsible chemical use and management, including minimizing emissions, identifying and implementing substitutes, and reducing use of these chemicals when and where possible. We will continue this work in the future."

Despite the phase-out of intentionally added PFOA in semiconductor manufacturing, additional research will be important to reduce the presence of PFOA in the environment. Two recent publications indicate that PFOA has been detected in certain fabrication wastewater streams.

While the completion of this phase out represents an important step, substantial work remains in tackling the challenges posed by the use of chemicals of concern in semiconductor manufacturing, including other types of PFAS.

Several years ago, SIA formed the Semiconductor PFAS Consortium, a group of semiconductor companies and suppliers engaged in addressing the technical issues surrounding the industry’s use of PFAS in the manufacturing process. The Consortium has published numerous papers on the use of PFAS in the semiconductor industry, the chemical and physical properties of these chemicals in addressing the unique performance needs of the semiconductor industry, and the challenges of finding alternatives to these chemicals that meet the functional demands of the semiconductor fabrication process.

The papers also document that additional work is needed to improve detection technologies, treatment and destruction methods, process optimization, and abatement systems. The research of the Semiconductor PFAS Consortium indicates that substituting other PFAS for alternatives will similarly be complicated and time consuming, ranging from 5-25 or more years, with no guarantee of success in all or any applications.

In 2017, the WSC also announced the phase out of the use of perfluorooctane sulfonic acid (PFOS), another long-chain PFAS with properties of concern.

-- Alex Gordon, Manager, Government Affairs, SIA, USA.