AN XPS STUDY OF PHOTORESIST SURFACES IN SF6-O2 R F PLASMAS

The behaviour of HPR 206 photoresist in SF6 and SF6-O2 plasmas was studied by X-ray photoelectron spectroscopy (XPS) in terms of surface composition. An important fluorination of the carbon framework is observed and discussed. In situ XPS analyses compared with ex situ XPS analyses give information about losses of surface products and contaminants which result from the contact of treated photoresist masks with the atmosphere. The interaction of materials that are to be etched with photoresists is approached by a study of tungsten etch products deposited on the polymer. A scheme is proposed which explains that WO(x)F(y) deposits are not due to cathodic sputtering but come from plasma gaseous species.