Method for manufacturing flash memory device

Abstract

The invention provides a method for manufacturing a flash memory device. When a sidewall of a gate stack layer is formed, a first protective layer is formed on a side wall of the sidewall; and the protective layer and the sidewall are etching-selective in a process of removing the sidewall in a word line region; in this way, when the sidewall in the word line region is removed, the protective layer can protect the sidewall of an erase gate region from being removed, and the sidewall of the erase gate region is a mask when a floating gate is formed. The protective layer can reduce or avoid damage to the mask forming the floating gate, thereby improving the uniformity of the formed floating gate, improving the erasing efficiency of the flash memory device and improving the performance of theflash memory device.

Description

technical field [0001] The invention relates to the field of semiconductor devices and their manufacture, in particular to a method for manufacturing a flash memory device. Background technique [0002] With the continuous development of semiconductor technology, memory has been widely used. Floating gate flash memory is a kind of non-volatile memory, which has the advantages of high integration, fast storage speed, and easy erasing and rewriting. [0003] As the application of flash memory becomes more and more extensive, embedding flash memory into other application system chips has become another main direction of flash memory development. In embedded flash memory, discrete gate flash memory devices are usually used, which have low programming voltage, The advantages of high programming efficiency, the floating gate in the discrete gate flash memory device is an asymmetric structure, the floating gate on one side protrudes from a part of the side wall, the side of the fl...

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Problems solved by technology

[0003] As the application of flash memory becomes more and more extensive, embedding flash memory into other application system chips has become another main direction of flash memory development. In embedded flash memory, discrete gate flash memory devices are usually used, which have low programming voltage, The advantages of high programming efficiency, the floating gate in the discrete gate flash memory device is an asymmetric structure, the floating gate on one side protrudes from a part of the side wall, the side of the floating gate on this side will form an erasing gate, and the floating gate on this side will be formed In the process, part of the floating gate on this side will also be etched away, resulting in poor uniformity of the floating gate, which will affect the erasing efficiency of the flash memory device and reduce the performance of the device

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