Recovery of perfluoroethane from chemical vapor deposition operations in the semiconductor industry

J. G. Wijmans*, Z. He, T. T. Su, R. W. Baker, I. Pinnau

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Perfluorocarbons, particularly perfluoroethane (C2F6), are widely used in the semiconductor industry for plasma cleaning of chemical vapor deposition (CVD) chambers. Although the quantity of C2F6 released into the atmosphere by these operations is relatively small, C2F6 is a very powerful greenhouse gas, and methods of reducing atmospheric emissions are being sought. One method is to use a selective membrane to concentrate the C2F6 so that the gas can be condensed on cooling and recovered as a liquid. In the past, similar membrane vapor separation processes used rubbery polymer membranes that permeate the vapor. However, perfluorocarbon vapors have unusually low permeabilities even in rubbery polymers, because of their large size and low solubility. Therefore, glassy polymeric composite membranes were developed to separate and recover C2F6 from CVD chamber exhaust gas. These membranes permeate oxygen and nitrogen, and retain the perfluorocarbon vapor. Membranes with nitrogen/C2F6 selectivities of up to several hundred were made from a number of polymers. A process using these membranes to recover 99% C2F6 from CVD exhaust gas was designed.

Original languageEnglish (US)
Pages (from-to)203-213
Number of pages11
JournalSeparation and Purification Technology
Volume35
Issue number3
DOIs
StatePublished - Mar 2004
Externally publishedYes

Keywords

  • Gas separation
  • Global warming
  • Membranes
  • Perfluorocarbons

ASJC Scopus subject areas

  • Filtration and Separation

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