Silicon epitaxial manufacturing method of capacitive three-axis micro gyroscope

Abstract

The invention discloses a processing and manufacturing method of a capacitive triaxial micro gyroscope. Two silicon substrates and a thick polycrystalline silicon epitaxy technology are provided, an electrode plate at the bottom layer of a polycrystalline silicon movable structure can be detected, and a seal cavity body internal electrical property structure and a cavity body external electrical property outer connecting structure are connected as well as single-layer metal electrical property interconnection and signal conduction can be realized; an interconnection track intersection area keeps away from the short circuit of the single-layer metal interconnection by utilizing the electrical property bridging of the polycrystalline silicon layer of the surface layer, and the electrical property bridging is realized through a grounding anchor point, internal and external electrical property connecting layers and an electrical property external connecting structure support structure of the cavity body. Compared with the traditional SOI (silicon on insulator) technology and a silicon glass bonding technology, according to the invention, the cost advantage is obvious; on the basis of saving a wafer as a structure layer, the vacuum packaging of the wafer level is realized; also the polycrystalline thickness control is simple, and a plurality of different thickness requirements can be realized; and meanwhile a layer of optical cover and a plurality of technology steps are reduced, and the product stability and reliability are improved.

Description

technical field [0001] The invention relates to a processing and manufacturing method for a capacitive three-axis micro gyroscope, in particular to a processing and manufacturing method for realizing the integrated lower plate detection function through epitaxial polysilicon technology and realizing electrical interconnection at the bottom of the polysilicon. The function of electrical intercommunication and wafer-level vacuum packaging can be realized through two silicon substrates and processing technology (wafer-level packaging, which means that the wafer is vacuum-packaged as a whole, which is different from the traditional single-chip vacuum packaging). Background technique [0002] The capacitive three-axis micro-gyroscope is a micro-electromechanical system-based motion chip that can be used to detect changes in angular velocity signals. It is widely used in industries such as national defense, automobiles, mobile phones, precision agricultural machinery, games, naviga...

AI Technical Summary

Problems solved by technology

[0003] Traditional micro-gyroscope processing technology, such as SOI (Silicon on isolator, silicon on insulating substrate) technology requires the use of two silicon substrates and one SOI wafer, and wiring on one of the silicon substrates to achieve electrical and signal connection functions , another silicon substrate is used as a vacuum cover, this process can also realize the function of a capacitive three-axis micro-gyroscope, but the cost is high due to the use of three silicon substrates, the process steps are more, and the surface layer needs to be customized because of the SOI wafer Silicon thickness, so the thickness control of the surface silicon, that is, the movable structure layer to be formed, is inflexible

[0004] Another traditional silicon-glass bonding process is wiring on the movable silicon structure to realize electrical interconnection and signal transmission, but only realizing the drive and detection of comb teeth on the movable silicon cannot realize all the functions of the three axes , especially when the movable structure vibrates up and down perpendicular to the horizontal plane, it is not ideal to detect the electrical signal only with the comb teeth, and the electrical signal on the silicon with the island structure in the middle cannot be extracted, so it is difficult to make a three-axis gyroscope.

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