PLASMA MODIFICATION OF POLYMER-FILMS STUDIED BY ELLIPSOMETRY AND INFRARED-SPECTROSCOPY

This polymer films (thickness d = 10 to 50 nm) modified in a low-pressure plasma of air, oxygen, argon, or tetrafluoromethane (p = 10 to 100 Pa) are investigated. It is shown that the interaction between plasma species (ions, electrons, radicals, UV quanta) and the polymer causes structural changes in the surface and subsurface regions. The formation of a modified surface layer can be observed. Fourier transform infrared (FTIR) attenuated total reflection (ATR) spectroscopy is used for the structural analysis of polymer modification. The structural changes detected by FTIR spectroscopy are accompanied by changes of optical properties, like the refractive index. The optical modification effects are investigated by spectroscopic ellipsometry (gamma = 300 to 800 nm). For the analysis of the modification depth a multilayer model has to be applied to fit the ellipsometric data.