CN201780110U

CN201780110U - Mems gyroscope

Info

Publication number: CN201780110U
Application number: CN2009200743032U
Authority: CN
Inventors: 邹波
Original assignee: Senodia Technologies Shanghai Co Ltd
Current assignee: Senodia Technologies Shanghai Co Ltd
Priority date: 2009-07-21
Filing date: 2009-07-21
Publication date: 2011-03-30
Anticipated expiration: 2019-07-21

Abstract

The utility model discloses an MEMS gyroscope, which comprises a stator and a rotor. The rotor comprises a monocrystal silicon mass block, sixteen symmetrical folding beam springs and four groups of movable comb teeth, the sixteen symmetrical folding beam springs are arranged on the periphery of the monocrystal silicon mass block and connected with the same, and the four groups of movable comb teeth are distributed around the rotor. The stator comprises four groups of fixed comb teeth, and the four groups of fixed comb teeth are crossed with the four groups of movable comb teeth on the rotor so as to form a capacitor. The MEMS gyroscope can realize effective decoupling by the aid of the symmetrical folding beam spring structures, and the monocrystal silicon mass block is centrosymmetric, so that the whole structure of the MEMS gyroscope generates matching resonant frequency in driving and sensing directions, has large resonant displacement in the driving direction, has high-quality factor in a sensing mode, and is low in mechanical crosstalk, thereby achieving the purposes of high flexibility and low noise.

Description

The MEMS gyroscope

Technical field

The utility model relates to a kind of MEMS (micro electro mechanical system) (Micro-Electro-Mechanical System is called for short MEMS), particularly relates to a kind of MEMS gyroscope.

Background technology

Growing along with the MEMS technology, the performance index of MEMS inertial sensor (comprising accelerometer and gyroscope) are more and more higher, all obtained using widely at industry-by-industries such as automobile, industry, medical treatment and consumption electronic products with little, the low-cost advantage of its size.

In the MEMS gyroscope, the oscillatory type silicon micro-mechanical gyroscope is modal a kind of gyroscope, this gyroscope utilizes Coriolis effect to detect the size of angular velocity, and its basic functional principle is: at first make the detection mass do line vibration or angular oscillation along driving direction, enter driving mode; When in angular velocity when input, arranged along the sensitive axes direction, coriolis force will appear detecting direction of principal axis, force detect mass along the detection side to there being displacement to produce.The size and the input angular velocity of coriolis force are proportional, and therefore the displacement variable that causes by the inspection coriolis force just can directly obtain the information of input angular velocity.

From the principle of above MEMS inertial sensor as can be seen, the factor of restriction MEMS gyroscope performance raising mainly contains two aspects at present: the one, and the problem of model frequency coupling, the resonance frequency that the oscillatory type gyro require to drive and detected mode is mated and is improved sensitivity, but the gyroscope of conventional design is because the variation of elasticity coefficient difference, process deviation, stress, environment temperature and the air pressure of spring beam etc. all can cause the resonance frequency drift.The 2nd, the modal coupling problem, the coupling that the MEMS gyroscope drives between mode and the detection mode can bring quadrature error, and quadrature error signal can sneak in the useful vibration signal that angular velocity signal causes, thereby increased gyrostatic noise, reduced gyrostatic performance.In order to solve above two problems, people have carried out the trial of the whole bag of tricks, but all do not have disruptive technology.

Simultaneously, present most of companies all use the material of polysilicon as the MEMS gyro, because the limitation of its manufacturing process is difficult to make high performance MEMS gyroscope with polysilicon.

The utility model content

The technical problems to be solved in the utility model is in order to overcome the defective of prior art, a kind of MEMS gyroscope is provided, it has adopted holosymmetric method designing quality piece, around mass, designed special flexure spring beam, on technology, adopt SOI (Silicon-On-Insulator, silicon on the dielectric substrate) technology has increased the quality of mass, thereby has optimized device performance.

The utility model solves above-mentioned technical matters by following technical proposals: a kind of MEMS gyroscope, it is characterized in that, it comprises stator and rotor, rotor comprises monocrystalline silicon mass, 16 symmetrical fold beam springs and four groups of movable comb, 16 symmetrical fold beam springs be positioned at the monocrystalline silicon mass around and link to each other with the monocrystalline silicon mass, four groups of movable comb be distributed in rotor around; Stator comprises four groups of fixed broach, and four groups of fixed broach intersect with epitrochanterian four groups of movable comb and form capacitor.

Preferably, described stator also comprises four anchor posts, and four anchor posts are distributed on four angles of monocrystalline silicon mass, and stator is fixed on the silicon substrate, and the monocrystalline silicon mass of rotor, symmetrical fold beam spring and movable comb are suspended on the silicon substrate.

Preferably, the figure of described monocrystalline silicon mass is a centrosymmetric image.

Preferably, the figure of described monocrystalline silicon mass is a kind of in square, octagon and the circle, or square, octagon and circular combination.

Preferably, described 16 symmetrical fold beam springs are serpentine spring foldable structure and center symmetry.

Preferably, described four groups of movable comb are divided into two groups of driving combs and two groups of detection combs, and driving comb is vertical with detection comb.

Preferably, described MEMS gyroscope is a kind of MEMS inertial sensor, and one-piece construction is about central point.

Positive progressive effect of the present utility model is: the utility model is by SOI disk technology, under the situation that keeps size sensor, increased the quality of mass itself, eliminated modal coupling by centrosymmetric rotor and folded spring syndeton, and made that driving mode mates with the detection model frequency.Gyroscope of the present utility model has highly sensitive, the advantage that noise is low.Simultaneously, this gyrostatic size is little, and processing is simple, and cost is low.In addition, the utility model is by the effective decoupling zero of symmetrical fold beam spring structure, the monocrystalline silicon mass is about the center symmetry simultaneously, total is reached in driving and induction direction resonant frequency matched is arranged, at driving direction big resonance shifts is arranged, under the inductive mode high-quality-factor is arranged, and low mechanical cross talk, thereby reach the target of high sensitivity and low noise.

Description of drawings

Fig. 1 is the gyrostatic structural representation of the utility model MEMS.

Fig. 2 is the structural representation of the utility model mass band release aperture.

Fig. 3 is the structural representation of the utility model middle part symmetrical fold beam spring.

Fig. 4 be the utility model driving direction and detection side to the structural representation of symmetrical fold beam spring.

Embodiment

Provide the utility model preferred embodiment below in conjunction with accompanying drawing, to describe the technical solution of the utility model in detail.

The utility model MEMS gyroscope obtains by processes such as photoetching, etchings on the SOI disk, specifically provide a wafer, this wafer is the SOI wafer, generates parts such as the gyrostatic stator of MEMS, rotor by technologies such as photoetching, etchings on the SOI wafer; The thickness of silicon is adjustable on the insulation course of SOI wafer, does not wait from several microns to hundreds of microns.Gyrostatic stator and rotor portion physical dimension can be optimized according to actual needs, finally make total reach one match resonant frequencies is arranged in driving and induction direction, at driving direction big resonance shifts is arranged, inductive mode has high-quality-factor, and low mechanical cross talk, thereby reach the target of high sensitivity and low noise.

As shown in Figure 1, wherein X and Y be meant respectively the gyroscope driving direction and the induction detection side to, gyrostatic rotor comprises 1,16 symmetrical fold beam springs of monocrystalline silicon mass and four groups of movable comb, stator comprises four anchor posts 2, the figure of monocrystalline silicon mass 1 is a centrosymmetric image, can be square, octagon, circle etc., also can be square, octagon, the combination of shapes such as circle, monocrystalline silicon mass 1 can move along directions X, also can move along the Y direction.16 symmetrical fold beam springs be positioned at the monocrystalline silicon mass around and link to each other with the monocrystalline silicon mass, the symmetrical fold beam spring is the serpentine spring foldable structure, and the center symmetry, folding number can be one or several, dozens of can be adjusted as required; As shown in Figure 2, monocrystalline silicon mass 1 is evenly carved a plurality of five microns release aperture 11 of taking advantage of five microns, and release aperture 11 is used for the optimization of sacrificial layer release process, releasing sacrificial layer when promptly being used to prepare suspension structure; Anchor post 2 is distributed on four angles of monocrystalline silicon mass 1; 16 symmetrical fold beam springs comprise the symmetrical fold beam spring 4 of four driving directions, four detection sides to symmetrical fold beam spring 6 and eight middle part symmetrical fold beam springs 7, as shown in Figure 3, eight middle part symmetrical fold beam springs are that the middle part connects spring and identical size and structure are arranged, and along the intermediate beam symmetry, every folded beam all is three microns wide, and any two adjacent folds case bays are ten microns; As shown in Figure 4, the symmetrical fold beam spring 4 of driving direction and detection side to the structure, measure-alike and of symmetrical fold beam spring 6 along the center line symmetry, these folded beam springs are fixed on the anchor post 2, and the spacing between any two adjacent folds beam springs is 13.6 microns.Four groups of movable comb be distributed in rotor around, wherein two groups of movable comb are driving comb, other two groups of movable comb are detection comb, driving comb is vertical with detection comb, driving comb comprises that first decides the tooth 3a and the first moving tooth 3b, decide to add that electrostatic force just can drive mass along the directions X to-and-fro movement between the tooth 3a and the first moving tooth 3b first, detection comb comprises that second decides the tooth 5a and the second moving tooth 5b, when the gyroscope thickness direction has the angular velocity input, coriolis force will appear in the Y direction, force mass to move along the Y direction, cause second of gyro detection comb to decide spacing change between the tooth 5a and the second moving tooth 5b, this spacing changes the differential capacitance that is brought and changes and can detect and finally obtain magnitude of angular velocity by external circuit.Wherein the driving comb mode of motion is the slide-film damping mode, and the detection comb mode of motion is the press-filming damping mode.Eight middle part symmetrical fold beam springs 7 are connected mass 1 on the first moving tooth 3b and the second moving tooth 5b.The conducting spring end is fixed on four anchor posts, and the other parts of rotor are suspended on the silicon substrate.

Gyrostatic stator is fixed on the silicon substrate, and stator comprises four groups of fixed broach, and they intersect with epitrochanterian four groups of movable comb and form capacitor.

The utility model MEMS gyroscope is a kind of MEMS inertial sensor, and one-piece construction is about central point, and its thickness is about 25 microns.

Though more than described embodiment of the present utility model, but those skilled in the art is to be understood that, these only illustrate, and under the prerequisite that does not deviate from principle of the present utility model and essence, can make numerous variations or modification to these embodiments.Therefore, protection domain of the present utility model is limited by appended claims.

Claims

1. MEMS gyroscope, it is characterized in that, it comprises stator and rotor, rotor comprises monocrystalline silicon mass, 16 symmetrical fold beam springs and four groups of movable comb, 16 symmetrical fold beam springs be positioned at the monocrystalline silicon mass around and link to each other with the monocrystalline silicon mass, four groups of movable comb be distributed in rotor around; Stator comprises four groups of fixed broach, and four groups of fixed broach intersect with epitrochanterian four groups of movable comb and form capacitor.

2. MEMS gyroscope as claimed in claim 1, it is characterized in that, described stator also comprises four anchor posts, four anchor posts are distributed on four angles of monocrystalline silicon mass, anchor post and stator are fixed on the silicon substrate, and the monocrystalline silicon mass of rotor, symmetrical fold beam spring and movable comb are suspended on the silicon substrate.

3. MEMS gyroscope as claimed in claim 1 is characterized in that the figure of described monocrystalline silicon mass is a centrosymmetric image.

4. MEMS gyroscope as claimed in claim 3 is characterized in that, the figure of described monocrystalline silicon mass is a kind of in square, octagon and the circle, or square, octagon and circular combination.

5. MEMS gyroscope as claimed in claim 1 is characterized in that, described 16 symmetrical fold beam springs are serpentine spring foldable structure and center symmetry.

6. MEMS gyroscope as claimed in claim 1 is characterized in that, described four groups of movable comb are divided into two groups of driving combs and two groups of detection combs, and driving comb is vertical with detection comb.

7. MEMS gyroscope as claimed in claim 1 is characterized in that, described MEMS gyroscope is a kind of MEMS inertial sensor, and one-piece construction is about central point.