Semiconductor structures and methods of forming them

Abstract

A semiconductor structure and a forming method thereof, the forming method comprising: providing a substrate including a unit memory area and a peripheral area, the gate stack structure of the unit memory area and the substrate forming a trench; forming a protective layer on the side wall of the trench; Form a barrier layer whose top is lower than the top of the gate stack structure in the trench; deposit a dielectric material and etch the dielectric material, form a side wall on the side wall of the gate stack structure in the peripheral region, and fill the remaining dielectric material to form a barrier layer trenches; removal of dielectric material, sidewalls, and protective layers higher than the top of the barrier layer; removal of the barrier layer; conversion of the exposed gate stack structure into a metal silicide layer; formation of the top covering the metal silicide layer and spacer The dielectric layer, the top dielectric layer is also located in the trench and seals the trench at the opening of the trench, and encloses a hole in the trench. The top dielectric layer has poor hole filling ability in the trench, so holes are formed in the trench, and the holes serve as air sidewalls, thereby reducing the capacitance between adjacent word lines.

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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