A Surface Study of Polyvinylidene Fluoride Pipe Exposed to High‐Purity Water Containing Dissolved Ozone

Abstract

Ultrapure water containing dissolved ozone is being increasingly considered for providing contamination-free environment required for advanced wet chemical processing of wafers, Fluoropolymers, including polyvinylidene fluoride, have become industry standard materials for the construction of piping and components used in the distribution of ozonated ultrahigh-purity water for the semiconductor industry. In order to determine the chemical stability of polyvinylidene fluoride in the presence of dissolved ozone, we used a number of complementary analytical techniques: scanning electron microscopy with energy dispersive spectroscopy, angle-resolved x-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectroscopy, and ion sputtering for chemical characterization of the polyvinylidene fluoride pipe surface. Both qualitative and quantitative information obtained from these analyses revealed a loss of fluorine with minor surface oxidation. This was found to be limited to several monolayers near the surface of the ozonetreated polyvinyldiene fluoride pipe. The loss of fluorine is explained via a dehydrofluorination mechanism which normally initiates via free radicals produced by interaction of ozone with polyvinylidene fluoride. Implications of such surface reactions for wet chemical cleaning of wafers for the semiconductor industry are discussed.

Fluorine Mobility During SEM-EDX Analysis: A Challenge for Characterizing Epoxy/Fluoropolymer Interfaces

“…Under the high-energy electron beam, fluorine is expected to be present mainly in the form of fluoride ion F – ; however, it should be noted that lower energy secondary electrons (<100 eV) in the fluoropolymer can also produce additional ionizations leading to the formation of free radicals, such as F*, H*, and HF*, and give rise to the creation of F 2 , H 2 , or HF molecules, as reported in ref . Therefore, the formation of HF (also known as dehydrofluorination , ), F 2 , or H 2 in small quantities and further away from the high-energy electron beam is not excluded (although it is considered to have a negligible influence in this study).…”