A kind of method for preparing micromechanical suspended structure on soi silicon wafer

Abstract

The invention discloses a method for preparing a micromechanical suspended structure on an SOI (Silicon on Insulator) silicon wafer. The suspended structure and a fixing structure thereof adopt different groove width designs, wherein the groove width of the fixing structure is obviously greater than that of the suspended structure; the bottoms of wide grooves firstly reach or approach to an SiO2 layer after being etched; furthermore through isotropic dry etching, the bottoms of narrow grooves are communicated with one another and are separated from an Si layer below the narrow grooves; beams among the narrow grooves are released to form the suspended structure with the flat bottom surface; meanwhile, Si at the bottom of the connecting area between the fixing structure and the suspended structure and Si at the bottom of an area between the fixing structure and other structures are removed; the fixing structure is isolated from the Si layer below the narrow grooves and other structures, and thus different fixing structures are insulated with one another. The method disclosed by the invention is simple and effective and can be widely applied to processing of MEMS (Micro-electromechanical System) suspended structures.

Description

technical field [0001] The invention belongs to the technical field of micro-mechanical electronic system processing, and more specifically relates to a method for preparing a micro-mechanical suspended structure on an SOI silicon wafer. Background technique [0002] Micro-electro-mechanical systems (MEMS) are more and more widely used in different fields, and the MEMS technology of silicon-based materials is developing particularly rapidly. A series of novel sensor and actuator structures with high aspect ratio silicon structures have been realized after the introduction of reactive ion deep etching into MEMS processing technology. MEMS devices using silicon on insulating substrate (Silicon-On-Insulator, SOI) technology not only have better silicon mechanical properties, but also make complementary metal oxide semiconductor (ComplementaryMetalOxideSemiconductor, CMOS) compatible with MEMS processing technology, which can promote MEMS devices are further miniaturized and in...

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Problems solved by technology

[0003] In view of the above defects or improvement needs of the prior art, the present invention provides a method for preparing a micromechanical suspended structure on an SOI silicon wafer, which can efficiently solve the problem of etching the bottom of the suspended structure to SiO 2 The irregular shape of the insulating layer due to the undercut phenomenon can be realized in the conventional reactive ion deep etching system to achieve the etching and release process, and obtain a suspended structure with a flat bottom surface

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