Three-dimensional memory and formation method for channel hole structure of three-dimensional memory

Abstract

Embodiments of the invention disclose a three-dimensional memory and a formation method for a channel hole structure of the three-dimensional memory. By implementing two times of a through hole formation process of a first through hole and a second through hole, the channel hole structure in the three-dimensional memory is formed, so that the process difficulty and cost of the channel hole structure can be greatly lowered; the problem of high process difficulty and high cost caused by overhigh depth-to-width ratio of the through holes under the same caliber are solved; and meanwhile, the manufacturing process difficulty and cost of the three-dimensional memory are lowered.

Description

technical field [0001] The invention relates to the technical field of three-dimensional memory, in particular to a three-dimensional memory and a method for forming a channel hole structure thereof. Background technique [0002] As the number of layers of ON (Oxide / Nitride) in three-dimensional memory (such as 3D NAND) increases, the depth of the channel hole formed in the three-dimensional memory becomes larger and larger, and the channel hole is formed by a single etching process. When , in the case of the same pore diameter, the greater the depth of the channel hole, the more difficult it is to etch. In particular, when the number of stacked layers in the three-dimensional memory reaches 120 or more, and then a single etching method is used to form channel holes penetrating through each stacked layer, there is a phenomenon that the etching time increases exponentially, the process efficiency is low, and the cost higher. Contents of the invention [0003] In order to ...

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Problems solved by technology

In particular, when the number of stacked layers in the three-dimensional memory reaches 120 or more, and then a single etching method is used to form channel hol

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