Method for improved plasma etching control
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsYi-Nien Su, Jen-Cheng Liu, Li-Chih Chao
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Abstract
A method for plasma etching is disclosed with improved etching selectivity for a nitride containing DARC and a low-k dielectric layer. Plasma chemistry is controlled by adjusting a nitrogen to oxygen ratio to achieve improved etching selectivity in both nitride containing and low-k dielectric layers. Nitrogen to oxygen ratios are adjusted to control etching of for example, a DARC nitride containing layer, and Carbon to fluorine ratios are additionally adjusted to control etching in a low-k dielectric layer.
Claims20
A method for plasma etching in an etch chamber with improved etching selectivity for a nitride containing material comprising the steps of:
- providing a substrate having a low dielectric constant material including at least one overlayer of a nitride containing material on top;
- depositing a photoresist layer overlying the at least one least one overlayer of a nitride containing material;
- patterning said photoresist layer photolithographically for an etching process;
- providing an ambient in said etch chamber conducive to forming a plasma including at least nitrogen and at least one compound selected from the group consisting of fluorocarbons and hydrofluorocarbons;
- forming a plasma in said etch chamber in the presence of microwave power;
- and
- adding oxygen and adjusting a nitrogen to oxygen ratio in said etch chamber whereby the at least one overlayer of a nitride containing material is preferentially etched through to a thickness to form an opening.
A method for plasma etching with improved etching selectivity for a dielectric material layer in an etch chamber comprising the steps of:
- providing a substrate having a dielectric material layer overlying a nitride containing underlayer formed on top;
- providing a photoresist layer overlying the dielectric material layer;
- defining a pattern in the photoresist layer such that a portion of the dielectric material layer is exposed for etching according to a photolithographic process;
- providing an ambient in said etch chamber conducive to forming a plasma including at least nitrogen and at least one compound selected from the group consisting of fluorocarbons and hydrofluorocarbons;
- forming a plasma in said etch chamber in the presence of microwave power;
- and
- adjusting a fluorine to carbon ratio whereby the dielectric material layer is preferentially etched through to a thickness of said dielectric material layer.
Dependencies are inferred from the claim text.