Methods and apparatus for selective dry etch

Abstract

Provided are methods for forming a spacer comprising depositing a film on the top, bottom and sidewalls of a feature and treating the film to change a property of the film on the top and bottom of thefeature, and selectively dry etching the film from the top and bottom of the feature relative to the film on the sidewalls of the feature using a high intensity plasma.

Description

technical field [0001] The present disclosure generally relates to methods of depositing thin films. More specifically, the present disclosure relates to a process for selectively depositing silicon nitride films by spatial ALD. Background technique [0002] Silicon nitride thin films as dielectric layers have been widely used in semiconductor manufacturing processes. For example, SiN films are used as spacer materials in multi-patterning processes to achieve smaller device sizes without using the most expensive EUV lithography. In addition, SiN can be used as a gate spacer material to isolate the gate structure from the contact area to minimize potential leakage current. [0003] The conventional silicon nitride spacer fabrication process consists of conformal SiN film deposition on 3D structures (e.g., fins), followed by directional plasma dry etching to remove top and bottom layers while maintaining sidewall films as spacers . However, it has been found that the dry e...

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Problems solved by technology

However, it has been found that the dry etch process can damage the sidewall surface and alter the film properties; ultimately affecting device performance and yield

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