Proposed PFOS ban may significantly impact semi industry
06/01/2001
ENVIRONMENTAL CONTAMINATION
Meg Villeneuve
SAINT PAUL, MN—;A proposed ban by the Environmental Protection Agency (EPA) on the manufacturing and distribution of the chemical Perfluorooctyl Sulfonates (PFOS), which serves as photoacid generators (PAGs) in the acceleration of the resist process, is prompting the semiconductor industry to search for a replacement.
Semiconductor Equipment and Materials International (SEMI) and the Semiconductor Industry Association (SIA) have submitted proposals to the EPA stating their positions on the issue.
In March, the EPA held a public meeting regarding the proposed Significant New Use Rule (SNUR) of PFOS. With numerous SIA members in attendance, SIA spokesperson Molly Marr says, "This is just the beginning. The EPA didn't know that so many [semiconductor companies] were effected by the 'proposed' ban."
At this time, the EPA is reviewing all the transcripts from the meeting. Officials from the EPA declined to say when a decision would be made. The SIA says it expects the EPA to hold another public meeting on the issue, but no date has been set.
One year ago, PFOS manufacturer 3M (St. Paul, MN) made the voluntary decision to discontinue the manufacturing of PFOS as of December 31, 2002. Officials from 3M said the company made the decision to phase-out PFOS because, "our own testing found these materials [PFOS] persistent in the environment and that they remain for a long period of time, and therefore we decided to phase it out."
Last year, the semiconductor industry's total consumption of PFOS PAGs was 975 kg, according to the SIA. "PFOS PAG is essential to the next few generations of semiconductor manufacturing at least," notes the SIA. "With the loss of PFOS photoresist additives, the consequences could be very dire. In particular if the US semiconductor industry is not able to use PFOS and others are not bound to do the same, there would likely be a migration of production to countries where the prohibitions do not exist."
Officials from SEMI said it supports the EPA in its efforts to "reduce the environmental impact of PFOS chemicals." But went on to say, "however, we believe that the proposed PFOS SNUR fails to take into account the ongoing and critical existing uses for these chemicals in the semiconductor industry and the industry's extensive procedures for appropriate handling and responsible disposal of these materials to minimize any human exposure and environmental impact."
Application exemptions
SEMI has asked the EPA to exempt certain applications from the SNUR, including the use of PFOS compounds as components in photoresist blends, antireflective coatings and photoacid generators.
In other news, the SIA has entered a partnership with the EPA, whereby the SIA will aid in the reduction of perfluorocompound (PFC) greenhouse gases used in semiconductor manufacturing.
To show its support for the reduction of PFCs the SIA voluntarily signed a "Memorandum of Understanding." PFCs are currently used in the following processes: plasma etching of thin films and cleaning chemical vapor deposition tool chambers.
Additionally, chipmaker NEC announced its plans to decrease its total volume of waste materials by five percent over the next three years, according to a report by Nihon Keizai Shimbun Inc.
NEC currently produces some 70,000 tons of waste per year. The decrease could be as much as 3,500 tons by 2005. Under the terms of the new initiative, NEC expects to cut the amount of PFCs used by 40 percent in both the photoresist and wafer cleaning processes.