A metal gate manufacturing method for 3D NAND memory

Abstract

The embodiment of the present application discloses a method for manufacturing a metal gate of a 3D NAND memory. The method includes: providing a substrate, a surface oxide layer is formed on the surface of the substrate, a stack structure in which silicon nitride layers and silicon oxide layers are alternately stacked is formed on the surface oxide layer, and vertical grooves penetrating the stack structure are formed in the stack structure At the bottom of the vertical channel hole, an epitaxial layer connected to the substrate is formed; the silicon nitride layer is removed to form a hollow stack structure; the interface between the hollow stack structure and the substrate is oxidized to diffuse oxidation to the interface Nitrogen in the interface; form an oxide layer on the sidewall of the epitaxial layer, and oxidize the surface area of ​​the substrate at the same time to form a new surface oxide layer of the substrate; fill the hollow area with a metal medium. Wherein, while oxidizing the sidewall of the epitaxial layer, the surface area of ​​the substrate can be oxidized. Therefore, this manufacturing method increases the thickness of the oxide layer between the metal gate and the substrate, thus reducing the distance between the metal gate and the substrate. There is a possibility of breakdown leakage between them.

Description

technical field [0001] The present application relates to the technical field of memory manufacturing, and in particular to a method for manufacturing a metal gate of a 3D NAND memory. Background technique [0002] NAND flash memory is a better storage device than hard disk drives, and it has been widely used in electronic products as people pursue non-volatile storage products with low power consumption, light weight and high performance. At present, the planar NAND flash memory is close to the limit of practical expansion. In order to further increase the storage capacity and reduce the storage cost per bit, a 3D NAND memory is proposed. [0003] In the existing 3D NAND memory manufacturing process (taking a silicon substrate as an example), after vertically etching the alternate stacked structure of silicon nitride / silicon oxide to form a vertical channel hole, the silicon is over-etched at the bottom of the vertical channel hole. A single crystal silicon groove is forme...

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Problems solved by technology

[0005] In view of this, the present application provides a metal gate manufacturing method of 3D NAND memory to solve the problem of breakdown leakage between the metal gate and the substrate of 3D NAND memory devices

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