Cantilever structure and its making process and application

Abstract

The invention relates to a cantilever beam structure and a manufacturing method manufactured by taking silicon anisotropic corrosion as a key technology, and belongs to the field of micro-electronic mechanical systems. It is characterized in that the section of the cantilever beam is pentagonal, the upper surface of the cantilever beam is a single crystal silicon (100) crystal plane, and the lower surface of the cantilever beam is composed of two (111) crystal planes. The cantilever beam structure is produced by anisotropic etching, and the (111) surface is used as the etching termination surface to automatically terminate the corrosion of the silicon cantilever beam. The cantilever beam structure can be precisely controlled, which greatly improves the manufacturing yield of the cantilever beam. The invention can be applied to the structures of various MEMS devices, such as capacitive acceleration sensors, resistive acceleration sensors, micromechanical gyroscopes, resonators, etc., which can greatly improve the control level of the device manufacturing process and improve the yield of device manufacturing.

Description

technical field [0001] The invention relates to a cantilever beam structure and a manufacturing method, more precisely, the invention relates to a cantilever beam structure and a manufacturing method manufactured with silicon anisotropic etching as a key technology. It belongs to the field of microelectromechanical systems. Background technique [0002] Cantilever beams are very important MEMS structural components, and can be applied to the structure of various MEMS devices, such as capacitive acceleration sensors, resistive acceleration sensors, micro-mechanical gyroscopes, resonators, etc. In the past fabrication of cantilever beams, silicon anisotropic wet etching method or dry etching method or a combination of dry etching method and wet method are mostly used. The cantilever beam made by the anisotropic wet etching method of silicon is to use the anisotropic etching characteristics of silicon to obtain cantilever beams with various cross-sectional shapes on (100) sili...

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Problems solved by technology

[0003] On the making of elastic beam, can adopt the method (L.BruceWilner, Differential capacitive transducer and method of making, US Patent no.4,999,735) of highly doped self-stop corrosion, although described method can control the thickness of beam at In a very small range, but due to the inhomogeneity of doping, the thickness of the beam is inconsistent, and more importantly, doping introduces stress, which will affect the performance of the device

[0004] The combination of dry etching method and wet method is usually carried out in two steps when making elastic beams. First, the pattern of the area where the cantilever beam is located is etched out to obtain a film with the desired thickness of the cantilever beam, and then use Dry etching technology to make elastic beams, such as W.S.Henrion, et.al, Sensors structure with L-shaped spring legs, US Patent No. 5,652,384, this method has difficulties in precisely controlling the thickness of the beams, which increases the complexity of the process, Moreover, expensive equipment is required, which increases the cost of device fabrication

[0005] Using a maskless etching method to form a cantilever beam, such as Jean Hermann et al., micromachinedmeasuring cell with arm supported sensor, US Patent No.5551294, this method increases the difficulty of controlling the thickness and shape of the cantilever beam

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