AVS 53rd International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS1-MoM

Paper PS1-MoM4
Systematical Evaluation of Etching Damage of Light, Radicals and Ions on Low-k Porous SiOCH Films

Monday, November 13, 2006, 9:00 am, Room 2009

Session: Etch for Advanced Interconnect I
Presenter: S. Takashima, Nagoya University, Japan
Authors: S. Takashima, Nagoya University, Japan
S. Uchida, Nagoya University, Japan
M. Hori, Nagoya University, Japan
K. Oshima, Sony Corporation, Japan
K. Nagahata, Sony Corporation, Japan
T. Tatsumi, Sony Corporation, Japan
Correspondent: Click to Email
In order to reduce the RC delay of ULSIs, insulating materials with lower dielectric constant (low-k) are introduced. The low-k films receive the damages from the plasmas in the etching and ashing processes. The plasma damages induce the increase of the dielectric constant of the films. In this study, we have investigated the etching damages of the low-k films by the process plasmas and clarified the influences of light, radicals, and ions in the plasmas on the properties of the low-k films systematically. The low-k film used in this study was the porous SiOCH film. In order to separate the influence of light, radicals and ions, we have developed a new technique, where the four kinds of etching samples were prepared. The MgF@sub 2@ and quartz window were put directly on the film, respectively, to clarify the influence of vacuum ultraviolet (VUV) light and UV light from the plasmas. The MgF@sub 2@ and quartz windows transmit the light of wavelength 115nm or more and 170nm or more, respectively. Si plate was put 0.7 mm above the film surface to investigate the influence of radicals. In order to clarify all the influences of light, radicals and ions, nothing was put on the film. The dual frequency CCP apparatus of 8 inch wafer was used. The refractive index and the film thickness were measured by an ellipsometer. At a VHF power of 500W, a bias power of 500W, a gas flow rate ratio H@sub 2@/(H@sub 2@+N@sub 2@) of 50%, and a pressure of 5.3 Pa, the increase of the refractive index was caused by not only the radicals and the ions but also the VUV and UV lights from the plasmas. On the basis of results, degree of the damages induced by individual species and light have been clarified.