Silicon dioxide etching method

Abstract

The invention provides an etching method of silicon dioxide. The etching method comprises the following steps: introducing an etching gas and an auxiliary gas into a reaction chamber and turning on an excitation power supply and a bias power supply so as to etch silicon dioxide, wherein the etching gas comprises a fluorocarbon gas or a fluorocarbon-hydrogen gas or a combination of the two gases; the auxiliary gas comprises hydrogen and argon; and chamber pressure of the reaction chamber and bias power of the bias power supply are set in the following way: plasma density of the etching gas is increased by raising chamber pressure and selection ratio of etching is enhanced by reducing bias power, so as to obtain an etch morphology with vertical sidewall. By the etching method of silicon dioxide, the etch morphology with vertical sidewall can be obtained on the precondition of guaranteeing silica surface and sidewall morphology.

Description

technical field [0001] The invention relates to the technical field of semiconductor processing, in particular to a silicon dioxide etching method. Background technique [0002] In recent years, with MEMS devices and MEMS systems being more and more widely used in the fields of automobiles and consumer electronics, and the broad prospects of TSV through hole etching (Through Silicon Etch) technology in the future packaging field, dry plasma deep silicon The etching process has gradually become one of the hottest processes in the field of MEMS processing and TSV technology. Etching trenches on silicon dioxide is a common etching process, and for different applications, the requirements for the etching morphology of trenches are also different. For example, some applications will require etch topography with vertical sidewalls. [0003] The existing silicon dioxide etching method usually uses fluorocarbon (CxFy) gas as the etching gas to etch silicon dioxide, and the total f...

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Problems solved by technology

The etching morphology obtained by the silicon dioxide etching method is as follows: figure 1 As shown, it can be seen from the figure that the inclination angle of the sidewall is 80°, so the silicon dioxide etching method cannot obtain the vertical etching morphology of the sidewall

[0004] In addition, the above silicon dioxide etching method also has the following problems, that is, due to the high bias power, this will lead to a decrease in the etching selectivity, which cannot meet the application fields that require high etching depth.

In addition, higher bias power will also cause damage to the silicon dioxide surface and sidewalls, resulting in lower product yields when manufacturing devices that have higher requirements on the silicon dioxide surface and sidewall morphology

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