Characterization of Al, Cu, and TiN surface cleaning following a low-K dielectric etch

The cleaning of Al, TiN, and Cu blanket samples was investigated in a high density inductively coupled plasma reactor, and compared with results for silicon. After simulating the dielectric overetch exposure of these substrates to a CHF3 discharge, an in situ O2 plasma clean and subsequent Ar premetal sputter clean were performed and evaluated using ellipsometry and x-ray photoelectron spectroscopy. Following the fluorocarbon exposure, significant C and F residues were observed. Exposure to a O2 plasma clean greatly reduced this contamination. Subsequent treatment with an Ar sputter further reduced the thickness of the modified surface layer. Comparisons of the cleaning results with silicon suggest an efficient cleaning procedure, especially in the cases of copper and titanium nitride. The response of several blanket, oxide-like low-K dielectrics to the O2 plasma treatment were also studied and compared to SiO2. While a fluorinated SiO2~SiOF! exhibited SiO2-like stability, deep modifications were observed in both hydrogen silsesquioxane and methyl silsesquioxane, consistent with the removal of hydrogen and carbon from these films. These results were compared to a dedicated chamber design, where no fluorocarbons contaminate the reactor. The dedicated chamber methodology offered no significant advantage. © 1999 American Vacuum Society. @S0734-211X~99!00204-8#