Manufacturing method of embedded flash memory

Abstract

The invention discloses a manufacturing method of an embedded flash memory. The method comprises the following steps: before forming a low-voltage device and a high-voltage device in a logic region, exposing the source line leading-out position of a source line leading-out region in an etching step of forming a word line in a storage region; during the formation of the grid electrode of the high-voltage device and / or the low-voltage device, by utilizing a protection layer of a first gate oxide layer, removing a first gate oxide layer on an erased gate structure above the source line leading-out position; generating a second gate oxide layer subsequently; utilizing the thickness difference between the first gate oxide layer and the second gate oxide layer, removing the second gate oxide layer and taking the remaining first gate oxide layer as a hard mask; removing one part of the erased gate structure above the source line; removing the remaining erased gate structure during the word line gate etching process and then forming a conductive plug to lead out the source line. In this way, the photoetching step of additionally leading out the source line and a photomask are omitted. Thepurposes of lowering the manufacturing cost of the embedded flash memory and lowering the complexity of the manufacturing process are achieved.

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] In the current semiconductor industry, integrated circuit products can be mainly divided into three types: analog circuits, digital circuits and digital / analog hybrid circuits, among which storage devices are an important type of digital circuits. In recent years, among storage devices, the development of embedded flash memory (Embedded Flash Memory) is particularly rapid. The main feature of embedded flash memory is that it can keep stored information for a long time without power on; and it has the advantages of high integration, fast access speed, easy erasing and rewriting, etc. field has been widely used. [0003] Existing device structure prototypes of embedded flash memories include the following three types: a single-transistor memory cell based on a stacked gate struc...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a method for manufacturing embedded flash memory, which is used to solve the problem caused by the use of additional photomask and photolithography steps when preparing the conductive plug used to lead the source line out in the prior art. Improve the manufacturing cost of preparing the embedded flash memory and increase the complexity of its manufacturing process

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