Method for preventing over etching of passivation layers

Abstract

The invention discloses a method for preventing over etching of passivation layers, comprising the following steps of: step A, preparing two passivation layers different in compactness on a substrate, wherein the passivation layer close to the side of the substrate is a compact passivation layer, while the passivation layer far away from the side of the substrate is a loose passivation layer; step B, applying a photoresist on the passivation layers through spin coating, and exposing and developing the photoresist according to a predetermined element template; step C, with the photoresist left after exposure and development on the substrate as the mask, performing dry etching on the loose passivation layer; and step D, with the photoresist left after exposure and development on the substrate as the mask, performing wet etching on the compact passivation layer. The method provided by the invention avoids over etching of the base layer SiC and also guarantees the etching quality by growing two SiO2 layers different in compactness and separately etching the two SiO2 layers different in compactness by combining the advantages of the wet etching and the dry etching.

Description

technical field [0001] The invention relates to the field of component preparation technology in the microelectronics industry, in particular to a method for preventing overetching of a passivation layer. Background technique [0002] As a new generation of wide bandgap semiconductor material, silicon carbide (SiC) has attracted more and more attention. It has the characteristics of large bandgap width, high critical breakdown field strength, high electron mobility, and high thermal conductivity. Widespread concern. At present, SiC-based Schottky barrier diode (JBS) devices have been widely used in the field of power electronics. SiO in SiC JBS devices 2 The passivation layer can reduce the injection damage, protect the surface of the chip from contamination, and play the role of a thick passivation medium in the field plate. [0003] At present, the etching process of the passivation layer mainly includes dry etching and wet etching. For wet etching, it has strong etchi...

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Problems solved by technology

In this way, it is impossible to judge whether SiO is etched by detecting the etching rate during the etching process. 2 The interface with SiC is prone to over-etching of SiC

[0004] This shows, above-mentioned existing SiO on SiC Passivation layer etching, obviously still have inconvenience and defective, and urgently need to be further improved

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