Semiconductor structure manufacturing method

Abstract

The invention discloses a semiconductor structure manufacturing method, which comprises the following steps: 1) forming at least one concave groove that penetrates a silicon nitride layer and goes deep into a substrate; 2) forming an isolation structure; 3) removing from the top a first thickness silicon nitride layer so as to expose the first section of the isolation structure; and conducting an etchback to the isolation structure to reduce the width of the first section; 4) further removing a second thickness silicon nitride layer so as to expose the second section of the isolation structure; and conducting an etchback to the isolation structure to reduce the width of the second section; 5) repeating the step 4 at least one time until the remaining silicon nitride layer is provided with a third thickness; 6) removing the remaining silicon nitride layer; and 7) depositing and obtaining a floating gate structure. According to the invention, in the manufacturing process of the floating gate, the floating gate is gradually enlarged to fill the upper opening while the active region CD at the bottom does not have to be enlarged. In this way, it is possible to enlarge the processing window and effectively avoid the appearance of holes in the floating gate. And it is also possible to better regulate the shape and appearance of the floating gate, increase the coupling rate of components and improve the breakdown performance between the active region and the control gate.

Description

Technical field

[0001] The invention belongs to the field of semiconductor technology and relates to a method for manufacturing a semiconductor structure. Background technique

[0002] In the current semiconductor industry, integrated circuit products can be divided into three main types: logic, memory, and analog circuits. Among them, memory devices account for a large proportion of integrated circuit products, such as RAM (random access memory), DRAM (dynamic Random Access Memory), ROM (Read Only Memory), EPROM (Erasable Programmable Read Only Memory), FLASH (Flash Memory), FRAM (Ferroelectric Memory), etc. The development of flash memory devices in memories has been particularly rapid, and they have become the mainstream of non-volatile semiconductor storage technology. Its main feature is that it can maintain the stored information for a long time without power on. It has many advantages such as high integration, faster access speed and easy erasing, so it is obtained in man...

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