Stage structure of three-dimensional memory and formation method of stage structure

Abstract

The invention discloses a stage structure of a three-dimensional memory and a formation method of the stage structure, and belongs to the technical field of a semiconductor. The method comprises the steps of providing a substrate; forming an array stacked structure on the substrate, wherein the array stacked structure comprises multiple layers of nitride layers and oxide layers which are depositedin a staggered manner with preset thicknesses, and the nitride layers are formed between adjacent oxide layers; and performing three times of an etching process in a Y direction on the array stackedstructure by adopting a mask plate to obtain three corresponding regions, and performing multiple times of the etching process in an X direction on the array stacked structure comprising the three regions by adopting the same mask plate to obtain the stage structure comprising multiple layers of stages. By virtue of the formation method, on the basis that the capacity and processing reliability ofthe three-dimensional storage are ensured, the volume of the three-dimensional memory is reduced, and the manufacturing cost of the three-dimensional memory is greatly lowered.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a step structure of a three-dimensional memory and a forming method thereof. Background technique [0002] With the continuous development of the demand for integration and storage capacity, three-dimensional memory emerges as the times require. Three-dimensional memory is a new type of product based on planar memory. Its main feature is to convert the planar structure into a three-dimensional structure to greatly save the area of ​​the silicon chip. Therefore, the step structure is one of the important components of the three-dimensional memory. Existing stepped structures are usually formed by depositing an oxynitride layer and combining an etching process; the thickness of each layer of the oxynitride layer is usually about 10 microns, and with the demand for large storage capacity, the number of layers of the stepped structure has increased. Doing more and more makes ...

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Problems solved by technology

Existing stepped structures are usually formed by depositing an oxynitride layer and combining an etching process; the thickness of each layer of the oxynitride layer is usually about 10 microns, and with the demand for large storage capacity, the number of layers of the stepped structure has increased. Doing more and more makes the virtual area (Dummy Staircase) that is not used to place real steps larger and larger, and the volume of the three-dimensional memory is also larger and larger; and in the etching process, each etching forms a layer of steps It is necessary to use a mask plate, which makes the manufacturing cost of the three-dimensional memory very high; in addition, in the existing step structure manufacturing process, usually more than two connection holes are formed on each step according to the requirements, and the process is complicated

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