| 摘要 |
A method of plasma etching a patterned tantalum nitride layer, which provides an advantageous etch rate and good profile control. The method employs a plasma source gas comprising a primary etchant to provide a reasonable tantalum etch rate, and a secondary etchant/profile-control additive to improve the etched feature profile. The primary etchant is either a fluorine-comprising or an inorganic chlorine-comprising gas. Where a fluorine-comprising gas is the primary etchant, the profile-control additive is a chlorine-comprising gas. Where the chlorine-comprising gas is the primary etchant, the profile-control additive is an inorganic bromine-comprising gas. By changing the ratio of the primary etchant to the profile-control additive, the etch rate and etch profile of the tantalum nitride can be controlled. For best results, the plasma is preferably a high density plasma (minimum electron density of 1011e-/cm3), and a bias power is applied to the semiconductor substrate to increase the etching anisotropy.
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