X-RAY PHOTOELECTRON-SPECTROSCOPY ANALYSES OF SILICON DIOXIDE CONTACT HOLES ETCHED IN A MAGNETICALLY ENHANCED REACTIVE ION ETCHING REACTOR

High aspect ratio SiO2 contacts are etched with a C4F8/CO/O-2/Ar chemi stry using a magnetically enhanced reactive ion etching (MERIE) plasma source with a good selectivity to the underlying silicon. X-ray photo electron spectroscopy (XPS) studies allow chemical analysis of high as pect ratio SiO2 contact holes. Using the charging effect, a complete s eparation of the XPS peaks originating from the resist mask and from t he bottom of the contact holes is possible. XPS analyses show that the fluorination of the polymer on the bottom of the contact is low (F/C around 0.2) and independent of the aspect ratio of contact holes. Furt hermore, XPS spectra also show that the full width at half maximum of the Si 2p doublet measured at the bottom of contact holes strongly inc reases, showing that the highly energetic ion bombardment induced by t he MERIE source lead to a severe amorphization of the silicon surface. Finally, comparisons between MERIE and high density plasma are discus sed. (C) 1998 American Vacuum Society.