PURITY AND THICKNESS ANALYSIS OF FLUOROPOLYMERS BY STATIC SECONDARY ION MASS-SPECTROMETRY

An ongoing concern in the area of magnetic thin film storage media is that of proper lubrication of Winchester-type disks. Without proper lubrication, catastrophic head crashes can occur. While thin fluoropolymer lubrication technology has been known and used for several years, the method still contains inherent problems. The overall thickness of the lubricant may be wrong, contamination of the fluoropolymer may be present, diffusion of sublayers can occur, and inhomogeneities in the lubricant thickness are present. This paper describes the use of static secondary ion mass spectrometry (SIMS) for the analysis of fluoropolyrner lubricants. Using extremely low primary ion current doses (<5X1012ion/cm2), static SIMS produces a set of characteristic molecular fragment ions whose intensity is found to be linear with thickness up to approximately 30 Å. The method also provides information on the purity of the lubricant as well as on surface coverage inhomogeneities which may be present. The technique has been shown to work for a variety of different perfluoropolyether lubricants as well as for an organic surfactant film. © 1990, American Vacuum Society. All rights reserved.