A method of manufacturing embedded flash memory

Abstract

The invention provides a method for manufacturing an embedded flash memory, comprising: dividing a semiconductor substrate into a flash memory area and a logic area, and sequentially forming a silicon dioxide layer, a floating gate polysilicon layer and a first silicon nitride layer on the semiconductor substrate , respectively forming shallow trenches in the logic area and the flash memory area; filling insulators in the shallow trenches to form shallow trench isolation; forming a second silicon nitride layer on the first silicon nitride layer and the shallow trench isolation ; forming a groove in the flash memory area; depositing an active polysilicon layer on the second silicon nitride layer to form a source in the groove; using chemical mechanical polishing to planarize the active polysilicon layer; using wet etching removing the first silicon nitride layer and the second silicon nitride layer; removing the floating gate polysilicon layer in the logic area, forming a CMOS structure in the logic area, and forming word lines in the flash memory area. The manufacturing method of the embedded flash memory provided by the invention saves the steps of the process and improves the efficiency of removing the second silicon nitride layer.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for manufacturing an embedded flash memory. Background technique [0002] Memory is used to store a large amount of digital information. According to recent surveys, memory chips account for about 30% of semiconductor transactions worldwide. Over the years, technological progress and market demand have led to more and more high-density various Type memory, such as RAM (random access memory), DRAM (dynamic random access memory) and FRAM (ferroelectric memory), etc., among them, flash memory is FLASH and has become the mainstream of non-volatile semiconductor storage technology, in a variety of FLASH Among devices, embedded flash memory is a kind of system on chip (SOC), which integrates logic circuit modules and flash memory circuit modules in an integrated circuit at the same time, and is widely used in smart cards, microcontrollers and other products...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a manufacturing method of embedded flash memory to solve the problem that the residual active polysilicon makes the silicon nitride layer difficult to remove

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