Conformal amorphous carbon for spacer and spacer protection applications

Abstract

A method of forming a nitrogen-doped amorphous carbon layer on a substrate in a processing chamber is provided. The method generally includes depositing a predetermined thickness of a sacrificial dielectric layer over a substrate, forming patterned features on the substrate by removing portions of the sacrificial dielectric layer to expose an upper surface of the substrate, depositing conformally a predetermined thickness of a nitrogen-doped amorphous carbon layer on the patterned features and the exposed upper surface of the substrate, selectively removing the nitrogen-doped amorphous carbon layer from an upper surface of the patterned features and the upper surface of the substrate using an anisotropic etching process to provide the patterned features filled within sidewall spacers formed from the nitrogen-doped amorphous carbon layer, and removing the patterned features from the substrate.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]Embodiments of the present invention generally relate to the fabrication of integrated circuits and particularly to a method for protecting sidewalls of hard mask spacers during an etching process.[0003]2. Description of the Related Art[0004]Reducing the size of integrated circuits (ICs) results in improved performance, increased capacity and / or reduced cost. Each size reduction requires more sophisticated techniques to form the ICs. Photolithography is commonly used to pattern ICs on a substrate. An exemplary feature of an IC is a line of a material which may be a metal, semiconductor or insulator. Linewidth is the width of the line and the spacing is the distance between adjacent lines. Pitch is defined as the distance between a same point on two neighboring lines. The pitch is equal to the sum of the linewidth and the spacing. Due to factors such as optics and light or radiation wavelength, however, photolithography ...

AI Technical Summary

Benefits of technology

This patent describes a method for protecting the sidewalls of hard mask spacers during an etching process. This is achieved by depositing a nitrogen-doped amorphous carbon layer on a patterned substrate, selectively removing the carbon layer from the patterned features, and then using an anisotropic etching process to provide patterned features filled within sidewall spacers. This allows for the formation of a device with improved etching precision. The technical effect of this method is improved protection of the hard mask spacers during etching processes, leading to more precise device formation.

Problems solved by technology

Due to factors such as optics and light or radiation wavelength, however, photolithography techniques have a minimum pitch below which a particular photolithographic technique may not reliably form features.

As a result, the material quality is poor, with low density and poor mechanical strength and degraded chemical resistance to subsequent etching chemistries.

Due to the poor material quality of typical ALD hard mask spacers, the sidewalls are damaged and thus causing higher line edge roughness.

This issue becomes serious with shrinking feature size.

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