Etching method to release mems suspension bridge structure

Abstract

The invention relates to an etching method for releasing an MEMS (Micro-electromechanical Systems) suspension bridge structure; and the method comprises the following steps of: first, etching a circular sheet with the MEMS suspension bridge structure by using an anisotropic etching process for alternately etching and protecting through SF6 and C4F8, so as to obtain a plurality of independent and adjacent grooves, which are substantially vertical to each other, in the circular sheet; communicating the adjacent grooves by using a SF6 and O2 mixed anisotropic etching process, so as to obtain a releasing space for the MEMS suspension bridge structure on the circular sheet. The etching method for releasing the MEMS suspension bridge structure, provided by the invention, has the advantages as follows: through the optimization of the traditional etching process and washing process, contaminant free deep silicon etching of an MEMS device with the suspension bridge structure is achieved, so that the reliability of the MEMS device is greatly enhanced and the failure rate is reduced.

Description

technical field [0001] The invention relates to an etching method for a silicon semiconductor device, in particular to an etching method for releasing a MEMS (Micro-Electro-Mechanical Systems, Micro-Electro-Mechanical Systems) suspension bridge structure. Background technique [0002] At present, in order to obtain a bulk silicon MEMS device with a suspension bridge structure, a process based on Bosch process evolution is mostly used to release the MEMS structure during deep silicon etching. The so-called process based on the evolution of the Bosch process is based on the vertical etching process of Bosch, and the SF is extended by an appropriate amount. 6 etch time while shortening the C 4 f 8 The protection time is long, and a deep silicon etching process with both deep etching and slight lateral etching is obtained. Using this process, the silicon substrate will be etched into individual trenches at the beginning, and the lateral etching will also increase as time incr...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is that the existing etching method for releasing the MEMS suspension bridge structure cannot avoid the defect that the MEMS device is contaminated by particles. The present invention aims to provide a new etching method for releasing the MEMS suspension bridge structure. Realize the contamination-free deep silicon etching of MEMS devices with suspension bridge structure, improve the reliability of MEMS devices and reduce the failure rate