Method for etching SiC through metal/oxide double-layer mask structure

Abstract

The invention provides a method for etching SiC through a metal / oxide double-layer mask structure, and the method at least comprises the steps: 1), providing an SiC epitaxial wafer, and growing an oxide mask layer on the surface of the SiC epitaxial wafer; 2), forming a photoresist layer on the surface of the oxide mask layer of a to-be-etched region of the SiC epitaxial wafer; 3), forming metal mask layers on the oxide mask layer and the surface of the photoresist layer; 4), removing the photoresist layer and the metal mask layer on the surface of the photoresist layer, and forming an etching window; 5), etching the oxide mask layer and the SiC epitaxial wafer to a needed depth through the etching window; 6), removing the residual metal mask layer and oxide mask layer, and obtaining an SiC gate groove structure. According to the invention, the oxide mask layer is taken as a blocking layer, thereby preventing the metal elements from diffusing towards the SiC epitaxial wafer and the substrate, and solving a problem of element pollution. In addition, the method can obtain a high-etching-rate gate and high-anisotropism groove structure with the smooth etching surface.

Description

technical field [0001] The invention relates to the field of semiconductor device manufacturing, in particular to a method for etching SiC by using a metal / oxide double-layer mask structure. Background technique [0002] Silicon carbide (SiC) material, as the third-generation wide bandgap semiconductor material, has the characteristics of high critical breakdown electric field, high thermal conductivity, and high electron saturation drift rate. It has great application potential in harsh environments such as high temperature or strong corrosiveness. [0003] For SiC gate trench structure devices such as UMOSFET, Trench Gate IGBT and SiC MEMS devices with three-dimensional structure, etch morphology, etch damage and etch surface residues have a great impact on the development and performance of SiC devices. The main difficulty in etching silicon carbide lies in the high mechanical hardness and chemical stability of silicon carbide materials. The actual process proves that t...

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Problems solved by technology

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a method for etching SiC using a metal / oxide double-layer mask structure, which is used to solve the problem of using a single layer of metal as a mask in the prior art. The problem of metallic elements contaminating SiC

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