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 s ilicon. After simulating the dielectric overetch exposure of these substrat es to a CHF3 discharge, an in situ O-2 plasma clean and subsequent Ar+ prem etal sputter clean were performed and evaluated using ellipsometry and x-ra y photoelectron spectroscopy. Following the fluorocarbon exposure, signific ant C and F residues were observed. Exposure to a O-2 plasma clean greatly reduced this contamination. Subsequent treatment with an Ar+ sputter furthe r reduced the thickness of the modified surface layer. Comparisons of the c leaning results with silicon suggest an efficient cleaning procedure, espec ially in the cases of copper and titanium nitride. The response of several blanket, oxide-like low-K dielectrics to the O-2 plasma treatment were also studied and compared to SiO2. While a fluorinated SiO2(SiOF) exhibited SiO 2-like stability, deep modifications were observed in both hydrogen silsesq uioxane and methyl silsesquioxane, consistent with the removal of hydrogen and carbon from these films. These results were compared to a dedicated cha mber design, where no fluorocarbons contaminate the reactor. The dedicated chamber methodology offered no significant advantage. (C) 1999 American Vac cuum Society. [S0734-211X(99)00204-8].