3D Memory Device Manufacturing: Reducing Epitaxial Defects
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Summary
Problems
The etching process for forming channel holes in 3D memory devices damages the semiconductor substrate and affects the quality of epitaxial structures, making it challenging to control the quality of these structures, especially as density increases, and the existing 3D memory architecture is limited by the damage to the ONO structure and channel layer during the etching process for exposing the epitaxial structure.
Innovation solutions
The method involves forming a vertical structure penetrating an alternating dielectric stack before removing the bottom dielectric layer and forming an epitaxial layer between the substrate and the stack, with an insulating layer replacing the bottom dielectric layer to reduce defects and enhance the manufacturing yield and electrical performance of the 3D memory device.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If an etching process is used to form channel holes penetrating the alternating dielectric stack, then the vertical structure can be formed, but the semiconductor substrate and epitaxial structures are damaged and quality control becomes difficult
Why choose this principle:
The bottom dielectric layer is removed before forming the vertical structure, so that when the vertical structure is formed by etching, the etching process does not damage the epitaxial layer that will be formed later. This preliminary removal of the bottom dielectric layer prevents the contradiction between forming the vertical structure and maintaining epitaxial layer quality.
Principle concept:
If an etching process is used to form channel holes penetrating the alternating dielectric stack, then the vertical structure can be formed, but the semiconductor substrate and epitaxial structures are damaged and quality control becomes difficult
Why choose this principle:
The alternating dielectric stack is segmented into multiple dielectric layers, with the bottom dielectric layer being removed separately before vertical structure formation. This segmentation allows the etching process to be isolated from the epitaxial layer, resolving the contradiction between productivity and manufacturing precision.
Application Domain
Data Source
AI summary:
The method involves forming a vertical structure penetrating an alternating dielectric stack before removing the bottom dielectric layer and forming an epitaxial layer between the substrate and the stack, with an insulating layer replacing the bottom dielectric layer to reduce defects and enhance the manufacturing yield and electrical performance of the 3D memory device.
Abstract
A three-dimensional (3D) memory device and a manufacturing method thereof are provided. The method includes the following steps. An alternating dielectric stack is formed on a substrate. A vertical structure is formed penetrating the alternating dielectric stack in a vertical direction. A bottom dielectric layer of the alternating dielectric stack is removed. An epitaxial layer is formed between the substrate and the alternating dielectric stack after removing the bottom dielectric layer. An insulating layer is formed on the epitaxial layer. The insulating layer is located between the epitaxial layer and the alternating dielectric stack. The influence of the step of forming the vertical structure on the epitaxial layer may be avoided, and defects at the interface between the epitaxial layer and the bottom dielectric layer may be avoided accordingly.