Deep silicon etching method

Abstract

The invention discloses a deep silicon etching method, and relates to the technical field of semiconductors. The method can improve the morphology of a sidewall. The deep silicon etching method comprises an initial deep silicon etching stage, the initial deep silicon etching stage comprises a plurality of primary deposition steps and a plurality of primary etching steps, the plurality of primary deposition steps and the plurality of primary etching steps are alternately carried out, the deposition time duration of the plurality of primary deposition steps successively decreases, and the etching time duration of the plurality of primary etching steps successively increases. The method is used for deep silicon etching.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a deep silicon etching method. Background technique [0002] In recent years, with the development of microelectronics technology, MEMS (Micro-Electro-Mechanical System, Micro-Electro-Mechanical System) has been highly valued by the governments and scientists of various developed countries. As the key to realizing MEMS, deep silicon etching technology has attracted more and more attention. [0003] At present, the Bosch process is mainly used for deep silicon etching. Specifically, the process of using the Bosch process for deep silicon etching is a process in which the etching step and the deposition step are alternately cycled. A layer of polymer is deposited on the walls as a protective layer to protect the sidewalls from erosion. [0004] However, the inventors of the present application have found that in the above-mentioned deep silicon etching process using the Bo...

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Problems solved by technology

[0004] However, the inventors of the present application have found that in the above-mentioned deep silicon etching process using the Bosch process, the etching rate is relatively fast at the initial stage of etching, and the isotropic etching is severe, which easily causes the top of the sidewall of the trench to be etched. Severe etching, which in turn causes bowing (convex belly) on the sidewall of the trench formed by etching, resulting in poor morphology of the sidewall of the trench, which will have a negative impact on the subsequent process

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