Semiconductor structures and methods of forming them

Abstract

A semiconductor structure and its forming method, the method includes: providing a substrate, including a unit memory area and a peripheral area, a plurality of gate stack structures on the substrate, and the first gate stack in the unit memory area away from the peripheral area Layer structure, the adjacent unit memory area in the peripheral area is the second gate stack structure, the adjacent gate stack structure of the unit memory area is connected with the substrate, the second gate stack structure and the gate of the adjacent unit memory area The electrode stack structure and the substrate form a trench; a cover layer is formed within the depth of the top part of the trench, and an air sidewall is formed with the adjacent gate stack structure and the substrate; when the first gate stack structure is far away from the second The side walls of the second gate stack structure and the side walls of the second gate stack structure away from the first gate stack structure form side walls. In the present invention, under the blocking effect of the covering layer, the side wall will not be formed in the groove, and the air side wall can reduce the capacitance between adjacent word lines, and improve the repeated reading and writing ability of the NAND flash memory device and the programming process. Crosstalk problem.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a semiconductor structure and a forming method thereof. Background technique [0002] At present, flash memory (Flash), also called flash memory, has become the mainstream of non-volatile memory (Non-volatile memory, NVM). According to different structures, flash memory can be divided into two types: Nor Flash and NAND Flash. 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 been widely used in many fields such as microcomputer and automatic control a wide range of applications. [0003] Due to the advantages of higher cell density, higher storage density, and faster writing and erasing speeds, NAND flash memory devices have gradually become a more commonly used structure in flash memory, and are currently m...

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Problems solved by technology

[0004] However, the performance of NAND flash memory devices still needs to be improved

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