Plasma preclean with argon, helium, and hydrogen gases
The present invention provides a method and apparatus for precleaning a patterned substrate with a plasma comprising a mixture of argon, helium, and hydrogen. Addition of helium to the gas mixture of argon and hydrogen surprisingly increases the etch rate in comparison to argon/hydrogen mixtures. Etch rates are improved for argon concentrations below about 75% by volume. RF power is capacitively and inductively coupled to the plasma to enhance control of the etch properties. Argon, helium, and hydrogen can be provided as separate gases or as mixtures.
Applied Materials, INC
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Xiangbing Kenny King-Tai Barney M.
Li Ngan Cohen