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8 August 1993 Advanced process with magnetically enhanced RIE for phase-shifting mask fabrication
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Phase-shifting needs the critical dimension (CD) accuracy to be less than 0.05 micrometers for the metal and shifter pattern on a phase-shifting mask. Thus we have investigated a new etching process using magnetically enhanced reactive ion etching (MERIE). A magnetic field was provided by two pairs of solenoid coils outside the chamber. By using this MERIE system, the etching characteristics of chromium (Cr) and spin on glass (SOG) were evaluated. A Cl2 and O2 gas mixture was used for Cr etching. The etching selectivity had a maximum when the concentration of O2 was 20%. The etching selectivity increased with an increase in the magnetic field and gas pressure as well as with a decrease in the rf power. High etching selectivity and anisotropic etching features were obtained when the magnetic field was 100 G, the gas pressure 10 - 30 Pa, and the rf power density 0.18 - 0.22 W/cm2. Phase-shifting masks fabricated with this system show a CD accuracy of better than 0.05 micrometers , so 64 MB DRAM phase-shifting masks can be successfully fabricated with this MERIE system.
© (1993) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Satoshi Aoyama, Haruhiko Kusunose, Minoru Hanazaki, Nobuyuki Yoshioka, Yaichiro Watakabe, Atsushi Hayashi, Akihiko Isao, and Yasuo Tokoro "Advanced process with magnetically enhanced RIE for phase-shifting mask fabrication", Proc. SPIE 1927, Optical/Laser Microlithography, (8 August 1993);

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