A method for etching silicon dioxide

Abstract

The invention relates to a silicon oxide etching method, and relates to the technical field of etching. The method can alleviate the etching load effect of silicon oxide. According to the embodiment of the invention, the method comprises the steps: carrying out the etching of the silicon oxide through etching gas which comprises octafluorocyclobutane gas and oxygen, wherein polymer generated by the octafluorocyclobutane gas in an etching process reacts with the oxygen to generate volatile gas.

Description

Technical field [0001] The present invention relates to the technical field of etching, in particular to an etching method of silicon dioxide. Background technique [0002] In the optical field, the optical waveguide technology in which several optical passive components are fabricated on the same substrate and then interconnected to form a functional loop through waveguides is a very practical technology. Since silica optical waveguides have good optical, electrical, mechanical properties and thermal stability, and low cost, silica optical waveguides are widely used in the field of optical waveguide technology. [0003] figure 1 It is a schematic partial cross-sectional view of a silica optical waveguide in the prior art. The silica optical waveguide has a narrow groove 1 and a wide groove 2. Generally, a dry etching method is used to etch silicon dioxide to form a silicon dioxide optical waveguide with the above-mentioned structure, for example, with octafluorocyclobutane (chemi...

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Problems solved by technology

During this etching process, C 4 f 8 The polymer generated by the chemical reaction is deposited at the bottom of the narrow groove 1. As the etching depth increases, the bombardment of the Ar plasma cannot completely remove the polymer deposited at the bottom of the narrow groove 1, resulting in an increase in the deposited polymer. Finally, the progress of the etching reaction is hindered, so that the etching of the narrow groove 1 is terminated, and the depth h1 of the narrow groove 1 is too small, so that the difference between the depth h1 of the narrow groove 1 and the depth h2 of the wide groove 2 is large, resulting in the oxidation of The etching loading effect of silicon is obvious, which affects the performance of silicon dioxide optical waveguide devices

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