Three-dimensional memory and its preparation method

Abstract

The present application provides a three-dimensional memory and its preparation method, including: forming an insulating layer on the surface of the substrate; etching the insulating layer to form a virtual ladder structure; forming a stack structure on the surface of the virtual ladder structure away from the insulating layer, wherein the stack structure Including a core area and a stepped area located around the core area; etching the stacked structure located in the stepped area to form a plurality of stepped structures of the same height arranged along a first direction, wherein the first direction is a direction in which the stepped area points to the core area; Conductive plugs are formed on one side of each step of each stepped structure, wherein each step of each stepped structure includes a gate layer, and each conductive plug is electrically connected to the gate layer of the corresponding step. connect. The present application solves the problem in the prior art that as the number of stacked layers and stacking height continue to increase, it becomes more and more difficult to etch all the contact parts at a single time, which easily leads to an increase in process and material costs.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a three-dimensional memory and a preparation method thereof. Background technique [0002] In the three-dimensional memory manufacturing process, in order to ensure that the contact portion can be smoothly connected to the gate in each memory array, it is necessary to form a three-dimensional (3D) ladder structure. With the rapid development of three-dimensional memory technology, the number of stacked layers of the memory array on the substrate is increasing, so the number of steps on the ladder structure is also increasing, which in turn leads to the closer to the step of the substrate, the etching forms the contact part connecting it The more difficult it is to etch, as the number of stacked layers and the stacking height continue to increase, the difficulty of etching all the contact parts at a single time will also become more and more difficult, which will easily lea...

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Problems solved by technology

[0003] In view of this, the present application provides a three-dimensional memory and its preparation method to solve the problem of increasing the difficulty of etching all the contacts in a single step as the number of stacked layers and the stacking height continue to increase in the prior art. , easily lead to the increase of process and material cost

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