3D NAND memory and manufacturing method thereof

Abstract

The invention provides a 3D NAND memory and a manufacturing method thereof. The method comprises the following steps of: by etching a substrate, strip-shaped raised first raised parts are formed on the substrate; the back selection gate oxides formed on the upper portions and the side walls of the first raised parts form back selection gate tangent lines, the subsequently-formed back selection gates are cut off, separation control over the back selection gates is achieved, the control time of the device is prolonged, and the RC delay effect of a word line layer of the device is reduced. Or while the first raised part is formed, columnar raised second raised parts which are distributed in an array manner are formed on the substrate. The storage structures distributed in an array mode and formed in the stacking structure correspond to the second protruding parts in a one-to-one mode, and part of the storage structures are formed on the first raised parts. The first raised parts and the second raised parts replace a selective epitaxial structure formed in a channel hole, the substrate patterning process is easy to control, and etching post-processing is not needed.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a 3D NAND memory and a manufacturing method thereof. Background technique [0002] As the feature size of devices in integrated circuits continues to shrink, 3D memory technologies that stack multiple planes of memory cells to achieve greater storage capacity and lower cost per bit are increasingly favored. [0003] In 3D NAND memory, the top select gate of a stacked gate is usually used to control the memory structure. As the number of stacked layers increases, the storage structure is controlled respectively through the back selection gate and the top selection gate. However, as the number of stacked layers increases, when forming the tangent line of the back selection gate, it is usually used to first form part of the stacked layer, then etch part of the stacked layer to form a trench, and fill the trench with insulating material to form the tange...

AI Technical Summary

Problems solved by technology

The process of this method is cumbersome, and the process of etching to form trenches will also cause damage to the substrate

When forming the storage structure, etch the stacked structure to form a channel hole, and then grow the selective epitaxial structure at the bottom of the channel hole. Before forming the selective epitaxial structure, the channel hole and the substrate need to be etched first. Cleaning, this cleaning process is easy to cause damage to the substrate, or the cleaning is not thorough, the substrate cleanliness is not enough, and the uniformity of the selective epitaxial growth structure is poor, etc.

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