A method for manufacturing a three-dimensional memory

Abstract

The invention provides a method for manufacturing a three-dimensional memory, which specifically includes: providing a substrate, a stacked layer on the substrate has a channel through hole penetrating through the entire stacked layer along the substrate height direction, and a channel hole is formed at the bottom of the stacked layer. In the silicon epitaxial structure, a first oxide layer, a nitride layer, a second oxide layer and a protective layer are sequentially formed on the sidewall of the channel via hole and the upper surface of the silicon epitaxial structure; the protective layer on the upper surface of the silicon epitaxial structure is etched, to form a gap exposing the second oxide layer; etching the second oxide layer through the gap by using a first wet process; etching the nitride layer by using a second wet process; and etching the first oxide layer by using a third wet process , to expose the silicon epitaxial structure, wherein the first wet process and the third wet process use the same etchant, which is different from the etchant used in the second wet process. The manufacturing method provided by the present invention can form the bottom structure of the channel via hole without affecting surrounding devices, so as to ensure good electrical characteristics of the device.

Description

technical field [0001] The present invention relates to the field of manufacture of semiconductor devices, in particular to a method of manufacture of a three-dimensional memory structure. Background technique [0002] In order to meet the development of efficient and inexpensive microelectronics industry, semiconductor memory devices need to have higher integration density. Regarding semiconductor memory devices, since their integration density is very important in determining the product price, that is, high-density integration is very important. For traditional two-dimensional and planar semiconductor memory devices, because their integration density mainly depends on the unit area occupied by a single memory device, the integration degree is very dependent on the quality of photolithography and mask technology. However, even if expensive process equipment is continuously used to improve the precision of photolithography and mask process, the improvement of integration d...

AI Technical Summary

Problems solved by technology

It is difficult to ensure the shape of the bottom of the channel through hole through the existing etching process. It is often difficult to etch through the charge storage layer when etching the charge storage layer, resulting in the failure of the chip, or it is easy to cause excessive etching, resulting in the channel through hole. Conduction with surrounding devices, causing leakage, and the adjustment window of the etching process is getting smaller and smaller

The existing manufacturing process not only cannot guarantee the yield rate of 3D memory, but also increases the manufacturing cost of 3D memory virtually.

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