An etching process and 3d NAND manufacturing process

Abstract

The invention provides an etching process and a manufacturing process of 3D NAND. The etching process includes: step S1, providing a substrate stack structure with a channel hole and forming an epitaxial layer at the bottom of the channel hole; step S2, providing a functional layer on the sidewall of the channel hole and the top of the substrate stack structure structure, the polysilicon layer of the functional layer structure is exposed; step S3, the polysilicon layer at the bottom of the functional layer structure is etched by dry etching, and the dry etching is plasma etching, and the plasma etching uses a radio frequency power source Plasma generation is performed synchronously with the bias RF power source; and step S4, using dry chemical etching to etch the functional layer structure at the bottom of the channel hole to expose the epitaxial layer. The synchronous pulse of the source RF power source and the bias RF power source is used for plasma generation, which effectively alleviates the redundant dissociation of the sidewall polysilicon layer and ensures the thickness of the sidewall polysilicon layer after etching.

Description

technical field [0001] The invention relates to the technical field of 3D NAND flash memory, in particular to an etching process and a 3D NAND manufacturing process. Background technique [0002] Flash memory (Flash Memory) is also called flash memory. The main feature of flash memory is that it can keep stored information for a long time without power on, and has the advantages of high integration, fast access speed, easy erasing and rewriting, etc. , so it has become the mainstream memory of non-volatile memory. According to different structures, flash memory is divided into NOR Flash Memory and NAND Flash Memory. Compared with NOR Flash Memory, NAND Flash Memory can provide high cell density, high storage density, and faster writing and erasing speed. [0003] However, the current development of planar flash memory has encountered various challenges: physical limits, such as exposure technology limits, development technology limits, and storage electron density limits. ...

AI Technical Summary

Problems solved by technology

[0014] The main purpose of the present invention is to provide an etching process and a 3D NAND manufacturing process to solve the problem that the SONO etching process easily causes excessive damage to the sidewall polysilicon in the prior art

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