A kind of preparation method of semiconductor structure

Abstract

The invention discloses a method for preparing a semiconductor structure, which at least includes the following steps: providing a substrate; forming a gate oxide layer on the substrate; forming a first polysilicon layer on the gate oxide layer; Forming a dielectric layer on the surface of the first polysilicon layer and the gate oxide layer, the dielectric layer forms a fence structure on the sidewall of the first polysilicon layer; forming a second polysilicon layer Layer on the dielectric layer; perform the first etching, the first etching removes part of the second polysilicon layer, and use the dielectric layer as a stop layer; perform the second etching , the second etching removes the dielectric layer on the first surface of the first polysilicon layer. The invention can improve the performance stability of semiconductor devices.

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 ...

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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.

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