Void Detection Method for 3D NAND Memory

Abstract

The present application provides a method for detecting holes in a 3D NAND memory, comprising: removing the part of the filling layer located on a plurality of stacked structures arranged at intervals; removing the second sacrificial layer and the part of the filling layer located adjacent to the second sacrificial layer The part between the layers; removing the second insulating layer and the part of the filling layer between the adjacent second insulating layers; forming a protective layer covering the sidewall and the bottom of the substrate; using the first wet method The etch process processes the 3D NAND memory and performs void detection. In the cavity detection method provided in the present application, the filling layer is partially removed to expose the top surface of the filling layer located between adjacent first sacrificial layers, and then the first wet etching process is used. The substrate is processed, and whether there is a hole in the filling layer is determined by detecting whether there is an etching trace on the substrate, so as to prevent abnormal leakage of the 3D NAND memory.

Description

technical field [0001] The present application relates to the technical field of memory manufacturing, in particular to a method for detecting voids in 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] At present, the manufacturing process of 3D NAND memory includes: forming a stack layer composed of insulating layers and sacrificial layers alternately stacked on the substrate; trimming and etching the stack layer to form a stack of multiple intervals in a stepped shape structure; forming a filling layer, and the filling layer fills the space a...

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Problems solved by technology

[0004] Wherein, during the process of forming the filling layer, a void may be formed in the filling layer, and after removing the sacrificial layer and filling the conductive material to form the gate, the void will make the bottom selective gate (BSG) communicate with the substrate, And cause abnormalities such as leakage, which in turn affects the product yield and production efficiency of 3D NAND memory

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