Formation method of flash

Abstract

The invention relates to a formation method of a flash. The formation method comprises the steps of providing a semiconductor substrate, wherein the semiconductor substrate comprises a core region and a peripheral region, forming shallow trench isolation structures with the top being higher than the semiconductor substrate in the core region and the peripheral region, forming a tunneling dielectric layer on the semiconductor substrate, forming a floating gate on the tunneling dielectric layer, wherein the thickness of the floating gate in the core region is greater than the thickness of the floating gate in the peripheral region, forming a leveling layer on the shallow trench isolation structures and the floating gate, wherein the upper surface of the leveling layer on the core region is flush with the upper surface of the leveling layer on the peripheral region, removing the leveling layer and the top of the shallow trench isolation structures so as to form grooves and exposing the top and the side surface of the floating gate again, forming a gate dielectric layer at the upper surface and the side surface of the floating gate, and forming a control gate on the gate dielectric layer. The formation method provided by the invention improves the data reservation capacity of the formed flash and improves the reliability of the flash.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for forming a flash memory. Background technique [0002] Flash memory (Flash), also known as flash memory, has become the mainstream of non-volatile memory. According to different structures, flash memory can be divided into two types: NOR Flash and NAND Flash. Or non-flash memory is suitable for applications such as mobile phones or motherboards that need to record system codes because of its fast reading speed. And non-flash memory is especially suitable for multimedia data storage because of its high density and high writing speed. [0003] Another classification method of flash memory can be divided into two types: floating gate flash memory (floating gate flash) and charge-trapping flash memory (CTF, charge-trapping flash). For flash memory with a floating gate structure, due to the existence of the floating gate, the flash memory can complete the read...

AI Technical Summary

Problems solved by technology

[0004] However, the formation method of the existing flash memory leads to the phenomenon that the data retention (data retention) capability of the formed flash memory is prone to decrease.

Images