Etching method and semiconductor device

Abstract

The invention belongs to the field of etching processing of semiconductor devices, and specifically discloses an etching method and a semiconductor device. The etching method includes: providing a substrate on which a film layer to be etched is formed; forming a mask layer structure on the film layer to be etched, wherein the mask layer structure includes a dielectric layer formed in the upper surface of the film layer to be etched and an APF film layer formed in the upper surface of the dielectric layer; patterning the APF film layer; by using the patterned APF film layer as a mask, performing a first etching process on the dielectric layer and the film layer to be etched so as to pattern the dielectric Layer and partially etch the film layer to be etched; removing the patterned APF filmlayer; and performing a second etching process on the film layer to be etched by using the patterned dielectric layer as a mask. The method can avoid the enrichment of a polymer generated in a polycrystalline silicon etching process on the surface of the APF, so as to eliminate defects of a polymer shell layer on the surface of the semiconductor device.

Description

technical field [0001] The invention relates to the field of etching processing of semiconductor devices, in particular to an etching method and a semiconductor device formed by the above etching method. Background technique [0002] With the continuous shrinking of semiconductor process nodes, the importance of hard mask etching for small-size polysilicon etching has become increasingly prominent. APF hard mask etching is due to its excellent line roughness (LER, Line Edge Roughness) performance, and for The high selectivity ratio of common etching film layers is widely used in polysilicon etching process. [0003] In a flash memory etching process with a novel structure, the erasing gate polysilicon (EP, Erase Polysilicon) etching process uses the APF as a hard mask to perform polysilicon etching. Due to the high step difference in the etched film layer structure, it is necessary to have a high amount of polysilicon etching in some areas. In addition, in order to protect...

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Problems solved by technology

Since the above-mentioned polymer shell layer 8 cannot be removed in subsequent etching and ashing processes, it will become a source of defects in subsequent processes

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