| AVS 54th International Symposium | |
| Plasma Science and Technology | Tuesday Sessions |
| Session PS1-TuA |
| Session: | Plasma Etching for Advanced Interconnects II |
| Presenter: | S. Uchida, Nagoya University, Japan |
| Authors: | S. Uchida, Nagoya University, Japan S. Takashima, Nagoya University, Japan M. Hori, Nagoya University, Japan M. Fukasawa, Sony Corporation, Japan K. Oshima, Sony Corporation, Japan K. Nagahata, Sony Corporation, Japan T. Tatsumi, Sony Corporation, Japan |
| Correspondent: | Click to Email |
The low-k films are wildy used as the insulating materials of ULSIs in order to reduce the RC delay. 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 order to realize the damage free plasma processes, it is necessary to clarify the influences of the light, the radicals, and the ions from the plasmas on the low-k films. In our previous study, in order to separate the effects of the light, the radicals, and the ions in the process plasmas, we have developed a new technique, where the four kinds of etching samples were prepared. We call the technique a pallet for plasma evaluation (Pape). These samples were as follows. The MgF2 and the quartz windows were put directly on the film, respectively, to clarify the influence of the vacuum ultraviolet (VUV) light and the ultraviolet (UV) light from the plasmas. The MgF2 and the 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 the light, the radicals, and the ions, nothing was put on the film. In this study, we have improved the Pape in order to evaluate the effect of the interaction of the light and the radicals. The advanced Pape is the methods of putting the MgF2 and the quartz windows 0.7 mm above the film surface. The low-k film used in this study was the porous SiOCH film. The dual frequency capacitively coupled plasma employing H2 and N2 gases was used in this study. 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 of 50%, and a pressure of 5.3 Pa, the ions induced the largest damage on the films. Moreover, the damage due to the interaction of the lights and radicals was larger than that due to the individual lights and radicals.