Method for manufacturing embedded flash memory

Abstract

The invention provides a method for manufacturing an embedded flash memory, comprising the following steps of: dividing a semiconductor substrate into a flash memory region and a logic region; sequentially forming a silicon dioxide layer, a floating gate polysilicon layer and a first silicon nitride layer on the semiconductor substrate, and forming shallow trenches in the logic region and the flash memory region respectively; filling an insulating material into 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 region; depositing an active polysilicon layer on the second silicon nitride layer so that a source electrode is formed in the groove; chemically and mechanically grinding to flatten the active polysilicon layer; removing the first silicon nitride layer and the second silicon nitride layer by means of wet etching; and removing the floating gate polysilicon layer from the logic region, and forming a CMOS (Complementary Metal Oxide Semiconductor) structure in the logic region so that a word line is formed in the flash memory region. According to the method for manufacturing the embedded flash memory provided by the invention, the steps of the technical process are saved and the efficiency of removing the second silicon nitride layer is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, and in particular, to a manufacturing method of 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, the advancement of process technology and market demand have spawned more and more high-density various Types of memory, such as RAM (random access memory), DRAM (dynamic random access memory) and FRAM (ferroelectric memory), etc. Among them, flash memory, namely FLASH, has become the mainstream of non-volatile semiconductor storage technology, in various FLASH In the device, embedded flash memory is a type of system on chip (SOC), which integrates logic circuit modules and flash memory circuit modules in an integrated circuit, and has a wide range of uses in smart cards, microcontrollers and o...

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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