Method for reaction ion deep etching to silica using compound mask

Abstract

The invention uses a compound masking technology combining the metal film and photoetching glue layer, realizes the deep etching process to the silicon dioxide. The invention uses photoetching glue and it generates no attaching particles in reaction ion etching process, and the etching selection rate is high of Cr, Al, NI metal masking films when F contained plasma to etch the silicon dioxide. It solves the deficiencies that the etched surface is coarse, radio frequency polarization can not too high, and the speed is slow in mask film etching process with metal film, at the same time, it can avoid the negative caused by using the single photoetching glue. The other character of the invention is: the thickness of the demanded metal film and the photoetching glue is less than the thickness in only using one of then, it can reduce the difficulty of filming process and etching process and the cost, upgrades the photoetching yield and the minimal figure resolution, and it can be realized easily.

Description

technical field [0001] The invention relates to a method for reactive ion deep etching of silicon dioxide by using a composite mask, in particular to a composite mask composed of a combination of an anti-etching metal film and a thick photoresist, which is used for silicon dioxide In the reactive plasma etching process of silicon, silicon dioxide planar optical waveguide devices are fabricated. Background technique [0002] Since the planar optical waveguide technology can realize the advantages that separate devices cannot achieve, such as optical integration, photoelectric hybrid integration, miniaturization and mass production, it has been considered as the development direction of optical communication devices since its appearance, and it is a research in the optical communication device industry. hotspots. Since the silicon-based silica waveguide can achieve good mode matching with the ITU-T standard single-mode fiber, and its manufacturing proc...

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Problems solved by technology

[0026] The purpose of the invention is to overcome the problems and deficiencies in the prior art, and to propose a method for reactive ion deep etching silicon dioxide using a composite mask, which solves the problem of etching the surface when a metal film is used as an etching mask. Defects that are rough, the RF bias cannot be too high, and the etching rate is not fast; avoid the negative effects of passivation of the sidewall corners simply using photoresist as a mask; under the premise of etching the same depth, the required photolithography The thickness of the glue can be greatly reduced, which reduces the difficulty of the photolithography process, improves the photolithography yield and the minimum pattern resolution; and the method is simple and easy to implement

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