Selective etching of stacks with carbon-containing masks

Abstract

A method is provided for etching a stack beneath a carbon-containing mask, the method comprising multiple cycles, each cycle being a carbon deposition step in which carbon is selectively deposited on the upper surface of the carbon-containing mask, activating the upper surface of the carbon-containing mask by colliding ions with the upper surface of the carbon-containing mask, and a hydrogen source, carbon tetrachloride (CCl4) and C x H y Cl z Flowing a deposit gas containing an organic chloride source selected from at least one of the following (wherein x>0 and z>0), and converting the deposit gas into a plasma, at least one C n Cl m The process includes a carbon deposition step of depositing carbon on a carbon-containing mask by forming radicals or ions of x>0 and z>0 with at least one H radical or ion, and an etching step of etching features within the stack.

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