Dual lateral wall for flash memory

Abstract

The invention discloses a double side wall used for a flash memory. The double side wall comprises a first ion strengthened oxide layer, a silicon nitride and a second plasma strengthened oxide layer. When applied in the double side wall of a flash memory unit array, and when an interlayer dielectric medium layer is settled, the second plasma strengthened oxide layer is removed; when applied in the secondary array of a peripheral device of the flash memory, and when a source electrode and a leakage electrode of the peripheral device are planted, all layers are reserved. When the interlayer dielectric medium layer is settled, the second plasma strengthened oxide layer is removed. The invention further discloses a manufacture procedure method applied to the double side wall of the flash memory. When the source electrode and the leakage electrode of the peripheral device of the flash memory are planted, the side walls are thick, and when the interlayer dielectric medium is settled, the side walls are thin. Therefore, the breakdown voltage of the peripheral high voltage circuit is improved, and hollow holes are not generated because of the compact array when the flash array conducts the filling of the interlayer dielectric medium.

Description

technical field [0001] The present application relates to a manufacturing method of a flash memory device, and more specifically, to a manufacturing method applied to double sidewalls of a flash memory device. Background technique [0002] In flash memory (Flash) applications, flash memory cell arrays and peripheral devices of flash memory have different performance requirements. Generally, the flash cell array (Flash Cell Array) requires a relatively small gap to ensure that the interlayer dielectric void (Inter Layer Dielectric Void, ILD Void) in the contact hole (Contact) area can be avoided. Therefore, the flash memory cell array needs narrow sides. wall. The peripheral devices of the flash memory cell array require relatively large clearances to meet the requirements of high-voltage devices. For example, charge pumps and electrostatic charging (ESD) devices in the peripheral devices require high voltage. [0003] In the prior art, commonly used double sidewall materia...

AI Technical Summary

Problems solved by technology

However, silicon nitride has a significant disadvantage that it is difficult to remove, so it is difficult to remove too much silicon nitride sidewall for the narrow sidewalls required by flash memory cell arrays

Although plasma-enhanced oxides or oxides / nitrides / oxides can be easily removed, their data retention characteristics are relatively poor and cannot meet the data storage requirements of flash memory cell arrays.

[0005] It can be seen that no matter whether a single silicon nitride, plasma-enhanced oxide or oxide / nitride / oxide is used as the sidewall in the prior art, it cannot meet the requirements of both the flash memory cell array and the peripheral device.

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