Film lithium niobate optical waveguide chip polishing device and polishing method thereof

Abstract

The invention provides a film lithium niobate optical waveguide chip polishing device and a polishing method thereof. A magnetic stirring table is used for driving a magnetic rotor to rotate in a polishing solution, then the polishing solution is stirred to generate flowing contact with the surface of a chip, polishing particles in the polishing solution generate half contact or sliding contact with the surface of the chip subjected to dry etching, slight particle bombardment is associated, meanwhile, alkali ions in a polishing solvent and the etched surface generate a chemical etching reaction, chemical etching and particle bombardment in the direction parallel to the etched surface are achieved through instant stirring of the polishing solution, then etching products deposited on the dryetched surface and spikes and protrusions generated by dry etching are removed, and the effect that the etched surface and the waveguide side wall are smooth is achieved. Compared with traditional contact type mechanical grinding and polishing and chemical-mechanical grinding methods, the device and the method have the advantages that the structure is simple, operation is simple and convenient, cost is low, and surface damage is small.

Description

technical field [0001] The invention relates to the field of integrated optical chip manufacturing and micro-nano processing, in particular to a thin-film lithium niobate optical waveguide chip polishing device and a polishing method thereof. Background technique [0002] Optical waveguide is the basic unit for building integrated optical functional devices and chips. Its transmission loss mainly depends on the scattering loss caused by the roughness of the side wall and surface of the optical waveguide, and the roughness of the surface and side wall of the optical waveguide depends on the etching of the optical waveguide. Technology, especially for thin-film lithium niobate crystal materials, its processing technology is more difficult than silicon oxide, silicon and polymer materials. At present, the etching of thin-film lithium niobate optical waveguide mainly adopts argon ion dry etching. The principle is to use Argon ions bombard the surface of the thin-film lithium nio...

AI Technical Summary

Problems solved by technology

[0002] Optical waveguide is the basic unit for building integrated optical functional devices and chips. Its transmission loss mainly depends on the scattering loss caused by the roughness of the side wall and surface of the optical waveguide, and the roughness of the surface and side wall of the optical waveguide depends on the etching of the optical waveguide. Technology, especially for thin-film lithium niobate crystal materials, its processing technology is more difficult than silicon oxide, silicon and polymer materials. At present, the etching of thin-film lithium niobate optical waveguide mainly adopts argon ion dry etching. The principle is to use Argon ions bombard the surface of the thin-film lithium niobate material. After dry etching, the sidewall and surface roughness of the optical waveguide are usually large, and the etching products generated during the etching process will continue to accumulate on the optical waveguide. The sidewall and surface further deteriorate the surface roughness of the optical waveguide, resulting in higher optical waveguide transmission loss

[0003] At present, there are two main methods to reduce the surface roughness of thin-film lithium niobate optical waveguide: one is to use inductively coupled plasma dry etching, and to reduce the deposition of etching products by continuously optimizing the radio frequency power and etching pressure. The method has high requirements on the performance of the etching equipment, is expensive, and has a limited effect on reducing the roughness of the etching surface; the second is to use polishing technology to smooth the surface of the optical waveguide, which is mainly used in micro-nano processing technology. Polishing on the plane of the wafer substrate, the method is to fix the wafer substrate on the polishing fixture, place the plane to be polished upside down on the polishing pad of the polishing machine, and use the polishing liquid to physically rub and chemically corrode the plane to achieve Polishing of the substrate plane, however, for the etched optical waveguide, due to the existence of the optical waveguide pattern, the traditional polishing process is difficult to polish the side wall of the optical waveguide, and the polishing process will cause damage to the surface of the optical waveguide

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