Preparation method of semiconductor structure

Abstract

The invention discloses a preparation method of a semiconductor structure. The preparation method at least comprises the following steps of providing a substrate, forming a gate oxide layer on the substrate, forming a first polycrystalline silicon layer on the gate oxide layer, forming a dielectric layer on the surface of the first polycrystalline silicon layer and the gate oxide layer, wherein the dielectric layer forms a fence structure on the side wall of the first polycrystalline silicon layer, forming a second polycrystalline silicon layer on the dielectric layer, etching for the first time, removing part of the second polycrystalline silicon layer by etching for the first time, and taking the dielectric layer as a stop layer, and etching for the second time, wherein the dielectric layer on the first surface of the first polycrystalline silicon layer is removed by etching for the second time. The performance stability of the semiconductor device can be improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for preparing a semiconductor structure. Background technique [0002] At present, in the process of manufacturing some flash memories, for example, when making gate structures, a dielectric layer is usually grown on the surface and sidewalls of polysilicon. In the process of etching polysilicon, since the dielectric layer is grown on polysilicon Around the layer, the dielectric layer on the sidewall of the polysilicon layer is relatively high, which is equivalent to a fence. When etching polysilicon, it is difficult to remove the polysilicon at the corner of the dielectric layer on the sidewall of the polysilicon layer. If it is completely removed, there will be polysilicon residues, which will cause a short circuit in the subsequent semiconductor structure, resulting in test failure and affecting device performance. Contents of the invention [0003] In view ...

AI Technical Summary

Problems solved by technology

[0002] At present, in the process of manufacturing some flash memories, for example, when making gate structures, a dielectric layer is usually grown on the surface and sidewalls of polysilicon. In the process of etching polysilicon, since the dielectric layer is grown on polysilicon Around the layer, the dielectric layer on the sidewall of the polysilicon layer is relatively high, which is equivalent to a fence. When etching polysilicon, it is difficult to remove the polysilicon at the corner of the dielectric layer on the sidewall of the polysilicon layer. If it is completely removed, there will be polysilicon residues, which will cause short circuits in the subsequent semiconductor structures, resulting in test failures and affecting device performance.

Images