阅读说明：本技术 一种几何补偿式的（100）硅微机械环形谐振陀螺 (Geometric compensation type (100) silicon micro-mechanical ring-shaped resonant gyroscope ) 是由 白泽森 崔健 杨振川 赵前程 于 2019-08-30 设计创作，主要内容包括：本发明涉及一种可以消除杨氏模量不对称的几何补偿式(100)硅微环形谐振陀螺,它由固定电极、锚点、中心轴、支撑梁,谐振环、衬底、电极引线组成。衬底、电极引线与其余部分的制造材料分别为7740玻璃、铬/金混合物与(100)单晶硅。陀螺的支撑梁有八根且等效刚度相同并沿圆周均匀分布,每两根之间互成45度,又分别与单晶硅的[110]和[100]晶向及其反向延长线互成22.5度。陀螺的谐振环为非等宽谐振环,在不同的位置增减小质量块以完成等效刚度的补偿。固定电极共有十七个,分别为一个中心电极、两个驱动电极,两个驱动检测电极,两个力平衡电极,两个敏感检测电极,八个静电调谐电极。本发明从设计上补偿了(100)硅材料的不对称,实现了环形陀螺的模态匹配。(The invention relates to a geometric compensation type (100) silicon micro-ring resonator gyroscope capable of eliminating Young modulus asymmetry, which consists of a fixed electrode, an anchor point, a central shaft, a support beam, a resonator ring, a substrate and an electrode lead. The materials of fabrication of the substrate, electrode leads and the rest were 7740 glass, chrome/gold mixture and (100) single crystal silicon, respectively. Eight supporting beams of the gyroscope have the same equivalent rigidity and are uniformly distributed along the circumference, the angle between every two supporting beams is 45 degrees, and the angle between each two supporting beams and the crystal directions of [110] and [100] of the monocrystalline silicon and the reverse extension lines thereof is 22.5 degrees. The resonance ring of the gyroscope is a non-equal-width resonance ring, and small mass blocks are increased and decreased at different positions to complete compensation of equivalent rigidity. The fixed electrodes are seventeen in total, and are respectively a central electrode, two driving electrodes, two driving detection electrodes, two force balance electrodes, two sensitive detection electrodes and eight electrostatic tuning electrodes. The invention compensates the asymmetry of (100) silicon material from the design and realizes the mode matching of the ring gyroscope.)

1. A geometry-compensated (100) silicon micro-ring resonator gyroscope with elimination of young's modulus asymmetry, for detecting vertical angular velocity, comprising: the device comprises a fixed electrode, an anchor point, a central shaft, a supporting beam, a resonant ring, a substrate and an electrode lead. The anchor point, the central shaft, the support beam, the resonant ring and the fixed electrode are all made of (100) monocrystalline silicon, the substrate is made of Pyrex7740 or silicon oxide, and the electrode lead is made of a chromium/gold mixture.

2. A geometry-compensated (100) silicon micro-ring resonator gyroscope of claim 1, wherein: and seventeen anchor points are electrically connected with the electrode leads respectively, and are in natural mechanical connection with the seventeen fixed electrodes through a deep etching technology. The seventeen fixed electrodes include a center electrode and sixteen circumferentially symmetric electrodes. The central electrode is also the central shaft of the gyroscope, the sixteen circumferentially symmetrical electrodes are distributed on the outer side of the resonant ring in a circumferentially symmetrical mode to form a squeeze film capacitor, and the distance between the central lines of every two adjacent electrodes is 22.5 degrees.

3. A geometry-compensated (100) silicon micro-ring resonator gyroscope of claim 1, wherein: eight supporting beams are uniformly distributed along the circumference, and an angle of 45 degrees is formed between every two supporting beams. The supporting beams respectively form an angle of 22.5 degrees with the crystal directions of [110] and [100] of the monocrystalline silicon and the reverse extension directions thereof, each supporting beam is formed by connecting n-stage symmetrical spring beams in series, so that the axial equivalent stiffness can be reduced, and the beam width can be increased to reduce the processing error.

4. A geometry-compensated (100) silicon micro-ring resonator gyroscope of claim 1, wherein: the resonance ring is a non-equal-width circular ring, the [110] direction is a 0-degree direction, and the anticlockwise direction is positive. Small masses are added at 45 degrees, 135 degrees, 225 degrees and 315 degrees inside the resonance ring; small masses are removed at 0 degrees, 90 degrees, 180 degrees and 270 degrees on the inner side of the circular ring, and the effect of adding and subtracting the small masses is to complete equivalent stiffness compensation.

The technical field is as follows:

the invention relates to a micromechanical gyroscope, in particular to a geometric compensation type micro-ring resonator gyroscope which is processed by (100) monocrystalline silicon and can eliminate frequency cracking caused by asymmetric Young modulus.

Background art:

a gyroscope is a device used to detect the angular velocity of an object as it rotates. The silicon micro gyroscope is a gyroscope manufactured by taking semiconductor silicon as a material based on a microelectronic process, has the advantages of high yield and low cost of standardized batch processing, benefits from a micro processing technology, small volume, light weight, impact resistance, low power consumption and low possibility of being interfered by the outside when being integrated with an integrated circuit, is commercially applied in large scale in consumer electronics, industrial robots and automobile unmanned planes at present, and shows great advantages and bright application prospects in the fields of weapons, aerospace and the like. The silicon micro-ring resonator gyroscope is the most mature gyroscope with highest precision, most stable performance and commercialization in the silicon micro-gyroscopes disclosed in the current market. The Coriolis force sensor works under the condition of mode matching, the driving mode frequency is equal to or approximately equal to the detection mode frequency during the mode matching, the detected Coriolis force is amplified by thousands of times through a mechanical structure, high-precision detection is achieved, and meanwhile due to the symmetry of the ring structure, the Coriolis force sensor has excellent impact resistance and temperature stability. The annular gyro produced by BAE company in England is successfully applied to carrier-borne missiles and rocket missiles of the American navy.

(100) Single crystal silicon is generally the material of choice for silicon micromechanical devices due to its properties of being easy to micromachine and thin and compatible with CMOS integrated circuit processes, however, since the young's modulus of (100) single crystal silicon is not symmetrically equal along its central axis, the driving frequency and the detection frequency of a ring resonator gyro fabricated therefrom cannot be equal or nearly equal, thereby affecting the accuracy of detection. The invention has the significance that the asymmetry of the Young modulus of the (100) monocrystalline silicon is eliminated and compensated from the angle of geometric figure design, so that the driving frequency and the detection frequency of the micromechanical ring-shaped resonant gyroscope manufactured by the (100) monocrystalline silicon are very close, and the mode matching is easy to realize.

The invention content is as follows:

the invention aims to provide a geometric compensation design, which can eliminate the asymmetry of Young modulus and is a silicon micro-ring resonator gyro when (100) monocrystalline silicon is used as a material.

In order to achieve the purpose, the invention adopts the following technical scheme: the utility model provides a can eliminate asymmetric geometric compensation formula (100) silicon micro-ring resonator gyro of young modulus, through the geometric design compensation to the gyro structure, has eliminated the non-axisymmetric nature of its young modulus of processing material, has realized the mode matching of annular gyro, drive frequency equals with the detection frequency promptly, its characterized in that: the device comprises a substrate, an electrode lead, a fixed electrode, an anchor point, a central shaft, a supporting beam and a resonant ring.

The anchor point, the central shaft, the supporting beam, the resonant ring and the fixed electrode use (100) monocrystalline silicon as processing materials. The substrate is made of Pyrex7740 or silicon oxide. The electrode lead is made of a chromium/gold mixture.

The substrate is deposited with electrode leads, the seventeen anchor points and the electrode leads are electrically connected and fixed on the substrate through anodic bonding, the seventeen anchor points and the seventeen fixed electrodes are naturally and mechanically connected through a deep etching technology, and the seventeen electrodes comprise a central electrode and sixteen circumferentially symmetrical electrodes. The central electrode is also the central shaft of the gyroscope, the sixteen circumferentially symmetrical electrodes are distributed on the outer side of the resonant ring in a circumferentially symmetrical mode to form a squeeze film capacitor, and the distance between the central lines of every two adjacent electrodes is 22.5 degrees. Among the sixteen electrodes, the [110] direction of the (100) monocrystalline silicon is taken as a 0-degree direction, the counter-clockwise direction is recorded, and the electrodes in the 0-degree direction and the 90-degree direction are differential driving electrodes; the 180-degree and 270-degree direction electrodes are differential driving detection electrodes; the electrodes in the 45-degree and 135-degree directions are differential force balancing electrodes, and the electrodes in the 225-degree and 315-degree directions are differential sensitive detection electrodes; the other eight are electrostatic tuning electrodes.

Eight supporting beams are uniformly distributed along the circumference, and an angle of 45 degrees is formed between every two supporting beams. These support beams are 22.5 degrees from each other in the crystal directions of [110] and [100] of single-crystal silicon and the opposite extension directions thereof, respectively, and it is not difficult to obtain that these eight support beams have equal Young's moduli in the crystal directions thereof, respectively, and thus these 8 support beams have the same equivalent stiffness, based on the Young's modulus characteristics of (100) single-crystal silicon. Each supporting beam is formed by connecting n-level symmetrical spring beams in series (n is more than or equal to 5 and less than or equal to 8), so that the aims of reducing equivalent stiffness, increasing beam width and reducing machining errors are fulfilled.

The resonance ring is a non-equal-width circular ring, the [110] direction is a 0-degree direction, and the counter-clockwise direction is recorded. Small masses are added at 45 degrees, 135 degrees, 225 degrees and 315 degrees on the inner side of the circular ring; small masses are removed at 0 degrees, 90 degrees, 180 degrees and 270 degrees on the inner side of the circular ring, and the effect of adding and subtracting the small masses is to complete equivalent stiffness compensation.

Due to the adoption of the technical scheme, the invention has the following advantages: 1. the supporting beam and the resonance ring have the same equivalent rigidity and equivalent mass after geometric compensation design, and mode matching is realized on theoretical design. 2. The support beam adopts a series design, and the equivalent stiffness is shared by multiple stages, so that the width of the spring beam is increased, and the sensitivity of the support beam to process errors during processing is reduced. 3. The gyroscope is processed by (100) monocrystalline silicon and is compatible with a CMOS (complementary metal oxide semiconductor) process, and the high-precision micro-electromechanical gyroscope structure and the single-chip integration of a circuit are favorably realized.

Drawings

FIG. 1 is an oblique two-side view of a silicon micro-ring resonator gyroscope

FIG. 2 top view of a silicon micro-ring resonator gyroscope

FIG. 3 side view of a silicon micro-ring resonator gyroscope

FIG. 4 supporting beam of silicon micro-ring resonator gyroscope

FIG. 5 shows a specific example of compensation

Detailed Description

The technical solutions of the present invention are described in detail below with reference to the accompanying drawings and the detailed description, but the scope of the present invention is not limited to the embodiments.

As shown in fig. 1 to 4, the present invention is a mode matching type micromechanical Z-axis ring resonator gyroscope based on patterned compensation, which includes a substrate 11 (or 33), an anchor point 31, a central axis 21, a support beam 22 (or 43), a fixed electrode 13, a resonator ring 23 (or 14), and an electrode lead 12 (or 32).

The anchor point 31, the central shaft 21, the support beam 22, the resonant ring 23, and the fixed electrode 13 are all made of (100) single crystal silicon. The substrate 11 is made of Pyrex7740 or silicon oxide. The electrode lead 12 is made of a chromium/gold mixture.

The substrate 11 is deposited with electrode leads 12, the electrode leads 12 are electrically connected with seventeen anchor points 31 and are fixed through anodic bonding, the seventeen anchor points are naturally and mechanically connected with the seventeen fixed electrodes 13 through a deep etching technology, and the seventeen electrodes comprise a central electrode and sixteen circumferentially symmetrical electrodes. The central electrode is also the central shaft 21 of the gyroscope, the sixteen circumferentially symmetrical electrodes are distributed on the outer side of the resonant ring in a circumferentially symmetrical mode to form a squeeze film capacitor, and the distance between the central lines of every two adjacent electrodes is 22.5 degrees.

Eight support beams 22 are evenly distributed along the circumference, and the angle between every two support beams is 45 degrees. These support beams are 22.5 degrees to each other with respect to the [110] and [100] crystal directions of the single crystal silicon and the opposite extension directions thereof, respectively.

The resonance ring 23 is a non-equal width circular ring, the [110] direction is a 0-degree direction, the anticlockwise direction is recorded, small mass blocks 42 are added at the positions of 45 degrees, 135 degrees, 225 degrees and 315 degrees of the circular ring, small mass blocks 41 are removed at the positions of 0 degrees, 90 degrees, 180 degrees and 270 degrees of the circular ring, and the effect of adding and subtracting the small mass blocks is to complete equivalent stiffness compensation.

FIG. 5 is an example of geometric design compensation for the ring resonator gyro drive frequency and the detection frequency. In the example, the initial ring has a width of 40 μm, a height of 120 μm, a radius of 2500 μm, a central axis with a radius of 500 μm, and the support beam consists of an n-7 pitch rectangular beam with a beam width of 28 μm.

When the directions of the eight support beams are aligned with the directions of [110] and [100] and their extension lines, respectively, the two operating modal frequencies of the ring gyro are 12120Hz and 11855Hz due to the asymmetry of the young's modulus in the directions of [110] and [100 ].

When the eight supporting beams are rotated by 22.5 degrees, the asymmetry of the Young modulus on the supporting beams is eliminated, and the difference between the two working modal frequencies of the ring gyroscope is further reduced to 11980Hz and 11937Hz respectively.

After mass blocks with the width of 5 mu m and the length of 370 mu m are respectively added on the resonant ring, the asymmetry of the Young modulus on the resonant ring is eliminated, the annular gyroscope realizes mode matching, and the frequency of two working modes is 11950 Hz.

Among the sixteen electrodes, the [110] direction of the (100) monocrystalline silicon is taken as a 0-degree direction, the counter-clockwise direction is recorded, and the electrodes in the 0-degree direction and the 90-degree direction are differential driving electrodes; the 180-degree and 270-degree direction electrodes are differential driving detection electrodes; the electrodes in the 45-degree and 135-degree directions are differential force balancing electrodes, and the electrodes in the 225-degree and 315-degree directions are differential sensitive detection electrodes; the other eight are electrostatic tuning electrodes. The present invention utilizes the resonant ring 23 to induce coriolis forces at resonance to measure the angular velocity of an object. The differential drive electrodes enable the resonant ring 23 to work under the resonant frequency, and the differential drive detection electrodes can detect the displacement of the resonant ring under forced vibration, so that amplitude and phase feedback control quantity is provided for the differential drive electrodes. The differential force balance electrodes provide an electrostatic balance force that counteracts precession of the resonant ring under the coriolis force, the electrostatic balance force being proportional to the amplitude of the precession under the coriolis force. The differential sensitive detection electrode is used for detecting the precession displacement of the resonant ring and providing feedback control quantity for the differential force balance electrode. In consideration of errors in the machining process, a small frequency difference exists between the driving modal frequency and the detection modal frequency after compensation design, and the frequency difference needs to be adjusted to be zero by applying voltages to the eight electrostatic tuning electrodes respectively. The toroidal gyroscope needs to operate in a high vacuum environment for optimal sensitivity and stability.