USES OF ULTRAVIOLET OZONE FOR HYDROCARBON REMOVAL - APPLICATIONS TO SURFACES OF COMPLEX COMPOSITION OR GEOMETRY

The use of ultraviolet (UV)/ozone treatment for the removal of hydrocarbon contamination is discussed for a number of substrates involving complex composition or geometries. Treatment of gold and silicon dioxide surfaces in a reactor attached on line to an x-ray photoelectron spectrometer showed that the chemistry of oxidized hydrocarbon on SiO2 differs from that on gold and the removal rate of hydrocarbon bonded to SiO2 is much faster than that on gold. Treatments of thin film transistor surfaces consisting of field oxides and metallurgical strips showed that considerably longer reaction times are required to clean the field oxide regions compared to treatment of a single component surface. Cross-contamination of specimen surfaces can occur if labile contaminants such as fluoride are present anywhere on the structure. UV/ozone treatment has also been investigated for obscured surfaces not directly irradiated by UV. Effective cleaning is still directly possible using ozone alone as a reactant, although the reaction time is longer.