Etching Mechanisms of Fluoroelastomer Seals and Performance Characteristics

In this paper, we report on seal performance and degradation mechanisms under a range of plasma processing conditions for several fluoroelastomer materials. Both direct and indirect plasma sources were used and the location of the test samples was varied to impact the chemical versus physical etching mechanisms. Perfluoroelastomer o-rings were exposed to NF₃, O₂, CF₄, or SF₆ plasmas. The weight loss after 90 minutes of exposure was measured. Surface roughening of fluoroelastomer seals occurred under different exposure conditions. EDS was employed to analyze particulate residue that formed during the testing and will be discussed in regards to particle generation and contamination. Surfaces were examined with optical microscopy and SEM. Etching mechanisms are discussed.