Structure of embedded flash memory and manufacturing method of embedded flash memory

Abstract

The present invention proposes an embedded flash memory structure and an embedded flash memory manufacturing method. Multiple active areas and multiple virtual active areas separated by shallow trench isolation structures are formed in a polysilicon device area. By defining shallow trench isolation structures in the polysilicon device area, The trench isolation photomask forms the patterned shallow trench isolation photoresist above the virtual active area and part of the shallow trench isolation structure, exposing the active area and another part of the shallow trench isolation structure. During ion implantation, in order to Without affecting the performance of the flash memory device, the angle of ion implantation is usually fixed. By adjusting the active area, virtual active area, shallow trench isolation structure and patterned shallow trench isolation photoresist line width and patterned shallow trench The spacing between the isolation photoresists avoids repeated injection of ions into the active area, ensuring the performance of the MPOL device without affecting the flash memory device. At the same time, it can save the photomask when forming WLSP1 and reduce production costs.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a structure of an embedded flash memory and a manufacturing method of the 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] The polysilicon device (Memory Poly) can provide a stable fixed current (Fixcurrent) for the embedded flash memory. In order t...

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Problems solved by technology

If the GSTI mask is used for ion implantation according to the existing scheme, and the performance of the flash memory device must be taken into account, the angle and dose of ion implantation cannot be adjusted, which will cause an excessively high threshold voltage of the MPOL device and affect its performance, making WLSP1 The photomask cannot be saved. In the semiconductor manufacturing industry, it is well known that the price of the photomask is very expensive. The manufacturing cost is usually calculated based on the cost of the photomask. Saving a photomask will greatly reduce the production cost

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