3D NAND etch

Abstract

Methods of etching film stacks to from gaps of uniform width are described. A film stack is etched through a hardmask. A conformal liner is deposited in the gap. The bottom of the liner is removed. The film stack is selectively etched relative to the liner. The liner is removed. The method may be repeated to a predetermined depth.

Description

technical field [0001] Embodiments of the present disclosure generally relate to etching methods for forming gaps or features in semiconductor devices. More particularly, embodiments of the present disclosure relate to etching methods for forming word lines in three-dimensional semiconductor devices. Background technique [0002] The semiconductor and electronics processing industries continue to strive for greater throughput while increasing the uniformity of layers deposited on substrates with greater surface areas. These same factors combined with new materials also provide a higher degree of circuit integration per substrate area. As the level of circuit integration increases, so does the need for greater uniformity and process control with respect to layer thickness. As a result, various techniques have been developed to deposit and etch layers on substrates in a cost-effective manner while maintaining control over the physical and chemical properties of the layers. ...

AI Technical Summary

Problems solved by technology

During the etch of thick stacks, the current etch process often damages the sidewalls of the gap, resulting in a gap thickness that is less uniform at the top of the stack than in the middle or bottom

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