SPACER PASSIVATION FOR HIGH-ASPECT RATIO OPENING FILM REMOVAL AND CLEANING

摘要

A method of making a semiconductor device includes forming a stack of alternating layers of a first material and a second material over a substrate, etching the stack to form at least one opening in the stack such that a damaged region is located on a bottom surface of the at least one opening, forming a masking layer on a sidewall of the at least one opening while the bottom surface of the at least one opening is not covered by the masking layer, and further etching the bottom surface of the at least one opening remove the damaged region.

主权项

1. A method of making a semiconductor device, comprising:
forming a stack of alternating layers of a first material and a second material over a semiconductor material; etching the stack to form at least one front side opening in the stack; forming a memory film over a sidewall and bottom surface of the at least one front side opening; forming a sacrificial cover layer over the memory film such that the sacrificial cover layer is deposited so that it preferentially forms over a sidewall portion of the memory film located over the sidewall of the at least one front side opening but not over a bottom portion of the memory film located over the bottom of the at least one front side opening; etching the bottom portion of the memory film at the bottom of the at least one front side opening to expose an upper surface of the semiconductor material while the sacrificial material layer protects the sidewall portion of the memory film during the etching step; removing the sacrificial cover layer; and forming a semiconductor channel in the at least one front side opening; wherein the method further comprises at least one of (a), (b) or (c):
(a) the memory film comprises a composite blocking dielectric comprising a high-k dielectric layer and a silicon oxide layer; and/or(b) forming a semiconductor cover layer between the memory film and the sacrificial cover layer and etching a bottom portion of the semiconductor cover layer at the bottom of the at least one front side opening to expose the upper surface of the semiconductor material while the sacrificial material layer protects a sidewall portion of the semiconductor channel during the etching step; and/or(c) etching the bottom portion of the memory film at the bottom of the at least one front side opening forms either a tapered opening or a reverse tapered opening.