Flash memory unit and manufacturing method thereof

Abstract

The invention provides a flash memory unit and a manufacturing method thereof. The manufacturing method of the flash memory unit comprises the steps of firstly, providing a substrate with an isolationside wall, wherein a recess exists in the bottom of the isolation side wall; then forming a first contact etching stop layer on the substrate, and filling the recess with the first contact etching stop layer; secondly, etching the first contact etching stop layer, and reserving the first contact etching stop layer in the recess; and finally, forming a second contact etching stop layer on the substrate and the first contact etching stop layer in the recess. By forming the contact etching stop layer twice, the problem that the bottom of the isolation side wall is insufficiently covered can be solved, and then the problem of data storage failure of the flash memory unit can be solved.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a flash memory unit and a manufacturing method thereof. Background technique [0002] Flash memory is a widely used non-volatile computer storage technology, which usually uses a floating gate or charge trapping structure to store charges in field effect transistors to form a memory unit. [0003] According to the difference between the logic gates during the read operation, there are two types of flash memory: NAND type and NOR type. NOR flash memory can perform independent read and write operations for each of its storage units, providing complete random access functions, so it can be used for non-volatile storage of executable programs and can replace volatile SRAM and DRAM. Moreover, NOR-type flash memory has great technical advantages over NAND-type flash memory: it provides a general-purpose non-volatile memory with complete random access function, which can be u...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a flash memory unit and its manufacturing method to solve the problem that the bottom of the isolation sidewall is insufficiently covered by the contact etch stop layer, and then block the sodium ions generated in the back-end process from entering the isolation sidewall, and solve the problem of the flash memory unit. Data save failure problem

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