| 简介 |
PROBLEM TO BE SOLVED : To provide a method for selectively removing high-k materials containing rare earth metallic oxide on a lower substrate or layer without forming any undercut at the lower part of a gate.
SOLUTION : A method is disclosed for selectively removing rare earth scandium oxide high-k materials (e. g. DyScO3) on Si or SiO2. For patterning a metal gate comprising TiN and TaN on top of a rare earth based high-k layer 2, chlorine-containing gas can be used since titanium and tantalum chlorides are volatile, and reasonable selectivity to other materials present on a wafer can be obtained. The Dy and Sc chlorides are not volatile, but they are water soluble. The surface layer of Dy and Sc comprising high-k materials gets chlorinated (brominated) during exposure to the Cl or Br comprising plasma, and can be removed after etch by a water rinse.
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