An optical waveguide structure etching method and optical waveguide structure

By pre-filling the trenches of the optical waveguide structure with dielectric material, the problems of increased aspect ratio and shading effect caused by the thickening of photolithography spin-coated SOC are solved, thus achieving optimized etching of the optical waveguide structure, reducing foot protrusion and improving sidewall steepness.

CN122284019APending Publication Date: 2026-06-26SHANGHAI INTEGRATED CIRCUIT RESEARCH & DEVELOPMENT CENTER CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
SHANGHAI INTEGRATED CIRCUIT RESEARCH & DEVELOPMENT CENTER CO LTD
Filing Date
2024-12-26
Publication Date
2026-06-26

AI Technical Summary

Technical Problem

In the existing technology, during the etching process of optical waveguide structures, the aspect ratio increases due to the thickening of the spin-coated SOC, resulting in a shielding effect, which causes the bottom of the optical waveguide structure to show a protruding foot phenomenon and a decrease in the steepness of the sidewalls.

Method used

Chemical vapor deposition is used to pre-fill the trenches of the optical waveguide structure with dielectric material to form a flat surface, which reduces the thickness of the film layer in the subsequent photolithography process, thereby reducing the aspect ratio of the etched structure. The optical waveguide structure is formed through multiple photolithography and etching processes.

Benefits of technology

This reduces the protrusion phenomenon in the optical waveguide structure, improves the steepness of the sidewalls, optimizes the etching results, avoids damage to the structure, and reduces damage during the etching process.

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Abstract

This application discloses an etching method and an optical waveguide structure, belonging to the field of semiconductor technology. Before subsequent photolithography, this application pre-fills the trenches after the initial etching using a chemical vapor deposition process. Filling the pre-etched structure creates a flatter surface compared to traditional trenched surfaces. Depositing the film layer for subsequent photolithography on this surface reduces the film thickness, thereby lowering the aspect ratio of the etched structure. Due to the reduced aspect ratio, more etching ions can reach the bottom of the structure, significantly reducing foot protrusions and resulting in steeper sidewalls, thus optimizing the etching results. Simultaneously, because the pre-etched structure is filled with a dielectric material, damage to the structure can be avoided by subsequent etching steps.
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