Plasma etching carbonaceous layers with sulfur-based etchants

Abstract

Etching of carbonaceous layers with an etchant gas mixture including molecular oxygen (O2) and a gas including a carbon sulfur terminal ligand. A high RF frequency source is employed in certain embodiments to achieve a high etch rate with high selectivity to inorganic dielectric layers. In certain embodiments, the etchant gas mixture includes only the two components, COS and O2, but in other embodiments additional gases, such as at least one of molecular nitrogen (N2), carbon monoxide (CO) or carbon dioxide (CO2) may be further employed to etch to carbonaceous layers.

Description

technical field [0001] Embodiments of the present invention relate to the electronics manufacturing industry, and more particularly to the process of plasma etching features in carbon-containing layers. Background technique [0002] As the feature size of device patterns becomes smaller than 100 nm, the critical dimension (CD) requirement of features becomes an even more important benchmark for stable and repeatable device performance. The amount of CD variation allowed across the substrate also scales with the scaling of the characteristic CD. For example, some applications may require a 3-sigma of less than 10 nm in order to achieve an average target CD of approximately 80 nm across a 300 mm diameter substrate. [0003] Also, due to the prevailing concepts such as device capacity and high aspect ratio (HAR) in the industry, the scaling of the horizontal dimension is faster than that of the vertical dimension. When this aspect ratio and CD control requirement is combined ...

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Problems solved by technology

However, such small process windows typically suffer from performance limitations that are not compatible with known method etch processes

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