AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS1-MoM

Paper PS1-MoM6
Using In-vacuo Electron-Spin-Resonance and Infrared Spectroscopy Technique in the Analysis of Surface Reactions of Low-k films during/after Plasma Processes

Monday, November 15, 2004, 10:00 am, Room 213A

Session: Low-k Dielectric Etching
Presenter: K. Ishikawa, Tohoku University, Japan
Authors: K. Ishikawa, Tohoku University, Japan
Y. Yamazaki, AIST, Japan
S. Yamasaki, AIST, Japan
T. Ozaki, Tohoku University, Japan
Y. Ishikawa, Tohoku University, Japan
S. Noda, Tohoku University, Japan
S. Samukawa, Tohoku University, Japan
Correspondent: Click to Email
Using in-vacuo electron-spin-resonance (ESR) and infrared spectroscopy (FT-IR) techniques, surface reactions of low-k (porous methylsilsesquioxane, MSQ) films during/after plasma processes were studied. To understand the reaction mechanism on the surface with impinging species as ions, radicals, and photons, creation of dangling bonds (DBs), namely, bond breaking, is indeed a key process. The created DBs are playing an important role for surface chemical reactions. Applying our knowledge about pure SiO@sub 2@, the extensive study was made with respect to the porous MSQ, which is a candidate for future 45 nm node devices. Samples were prepared by spin-on coating a film of porous MSQ, on a bare Si substrate. The substrate was placed in a parallel-plate type reactor. Plasma discharge was sustained for proccessing. Since the DBs are affected by air exposure, our in-vacuo measurement needs to observe real feature of DBs. Thus, soon after the plasma process, an ESR spectrum was measured following transferring to the ESR cavity under vacuum ambient. Carbon-DB in the film is identifiable from g-value of the ESR signal. This indicates that the plasma process creates easily carbon-DBs, which has a highly chemical reactivity with oxygen.@footnote 1@ We also carried out an experiment using FT-IR. On an infrared spectrum of the film after the process, the decrease of the peak arising from Si-CH@sub 3@ bonds was clearly observed. Tentatively, we speculate that not only reactive species but also plasma characteristics as emissions affects to creation of the carbon-DBs and the created C-DBs plays an important role for the surface modification during/after the plasma process. @FootnoteText@ @footnote 1@ K. Ishikawa, et al. Appl. Phys. Lett. 81, 1773 (2002).