CN106403921B - Metal structure multi-ring vibrating disk micro-gyroscope and preparation method thereof - Google Patents

Abstract

The invention discloses a metal structure multi-ring vibrating disk micro-gyro and a preparation method thereof. The micro-gyro comprises a packaging cover, a metal multi-ring vibrator, a metal electrode and a substrate from top to bottom, and the metal multi-ring vibrator is a vibration inertial vibrator. The mass is the object to be detected, and the metal multi-ring vibrator is built in the vacuum and closed space formed between the package cover and the substrate; the present invention adopts the metal multi-ring vibrator, and the processing of the metal plane structure is easy to realize, and the processing cost is low. Low; the metal structure has a high density, which can increase the inertial force of the structure and improve the performance of the device; the multi-ring structure increases the driving force and detection sensitivity of the micro-gyroscope device. The invention can achieve the purpose of achieving higher device precision and quality with lower cost and condition requirements.

Description

Metal structure multi-ring vibrating disk micro-gyroscope and preparation method thereof

technical field

The invention relates to a micro sensor for measuring angular motion, in particular to a metal structure multi-ring vibrating disk micro gyro and a preparation method thereof.

Background technique

At present, the widely used gyroscopes are mainly hemispherical resonant gyroscopes and light gyroscopes. Among them, the oscillator used in the hemispherical resonant gyroscope is a three-dimensional hemispherical thin shell structure, which is difficult to process, occupies more space, and is difficult to obtain a high quality factor, and the cost of the fiber optic gyroscope is high. The structure of the multi-ring vibrating disc micro-gyroscope is mainly composed of four parts, the substrate, the electrode, the vibrator and the packaging device. It has the characteristics of simple processing and small footprint, and can achieve a more stable effect. After the vibrator is driven, it vibrates in a certain mode. When there is an angular motion in the outside world, the mode changes. The electrode detects the change and outputs it. After demodulation and calculation, the actual angular motion is obtained. The multi-ring vibrating disc micro-gyroscopes currently used mostly use silicon or fused silica as the vibrator material, and other parts of the device also use silicon as the main material, and the processing complexity and processing cost are relatively high.

After retrieval, the Chinese invention application with the publication number 105466407A discloses a disc multi-ring outer double beam isolated ring resonator gyro, comprising: a base; a disc multi-ring outer double beam isolated ring resonator, including The outermost ring, multiple double-beam isolated rings, multiple concentric rings, and multiple spokes, wherein: the outermost ring is connected to the base, and the multiple concentric rings are connected by multiple spokes , both ends of the multiple double-beam isolated rings are respectively connected to the inner side of the outermost ring and the outer side of the largest ring among the multiple concentric rings; electrodes on the inner edge of the device, and each electrode is respectively connected to the substrate.

The above patents: 1. Made of silicon material and deep silicon etching and structural bonding process; 2. The outer ring is fixed, and the inner ring is excited and detected. Silicon materials and deep silicon etching and structural bonding processes are expensive.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the prior art, the present invention provides a metal structure multi-ring vibrating disk micro-gyro and a preparation method thereof, which increase the driving force and detection sensitivity of the micro-gyro device, and can achieve better performance with lower cost and conditional requirements. High device accuracy and quality purpose.

According to a first aspect of the present invention, there is provided a metal structure multi-ring vibrating disc micro-gyro, which includes a package cover, a metal multi-ring vibrator and a substrate from top to bottom, wherein:

A vacuum-enclosed space is formed between the packaging cover and the substrate, and the metal multi-ring vibrator is encapsulated in the vacuum-enclosed space;

The metal multi-ring vibrator includes a metal vibrator structure and a support column, the supporting column is located in the center of the metal multi-ring vibrator, the metal vibrator structure is composed of a plurality of concentric metal rings, and two adjacent metal rings are composed of The spokes are evenly distributed in the circumferential direction, and the innermost metal ring is connected by the spokes. The adjacent metal rings and the spokes partially enclose grooves in the metal multi-ring vibrator, and the formed multiple grooves are on the metal vibrator structure. Evenly distributed;

There is a gap between the metal oscillator structure and the substrate, forming a suspended structure, the support column is arranged on the upper surface of the substrate, and forms a fixed connection with the substrate, and the metal oscillator structure is connected with the support column through the innermost spokes;

In the metal multi-ring vibrator, several pairs of driving electrodes are arranged in the groove of the inner ring, and several pairs of detection electrodes are arranged in the groove of the outer ring.

Preferably, the encapsulation lid includes a top, and a bonding metal layer and a vacuum getter below the top.

Preferably, a bonding layer of a packaging cover is provided on the substrate, and the bonding layer and the bonding metal layer are bonded to form a vacuum-enclosed space.

Preferably, an interconnection layer is provided on the substrate, the interconnection layer draws and introduces electrical signals on the detection electrodes and the driving electrodes, an insulating layer is provided on the interconnection layer, and the insulating layer is located at the bottom of the detection electrodes and the driving electrodes , forming electrical isolation from surrounding structures.

Preferably, the driving electrodes and the detection electrodes are fabricated on the upper surface of the substrate and form a fixed connection with the substrate.

Preferably, when the metal multi-ring vibrator is in a static state, by applying an alternating excitation signal to the driving electrode, the metal multi-ring vibrator will generate a reference vibration, that is, the first vibration mode, and the mode shape is between elliptical and circular. At this time, the outside world inputs a counterclockwise angular velocity to the vibrating metal multi-ring oscillator on the plane. If a certain point on the metal multi-ring oscillator is moving towards the center of the metal multi-ring oscillator, according to the Coriolis effect, the point is affected by the Coriolis effect. The influence of the force is shifted upward. Due to the conservation of rotation, the gyro will precess, and the precession angle is θ. Therefore, the vibration mode of the metal multi-ring vibrator has a counterclockwise offset phenomenon. The deflection of the vibration mode is the first angle. Two vibration modes.

The multi-ring vibrating disc micro-gyro with metal structure of the present invention is made of metal material and electroplating process, and the cost is lower; meanwhile, the metal structure has higher density, which is beneficial to improve the Coriolis force and the sensitivity of the gyro. The present invention adopts the structure of inner ring fixing, inner ring excitation and outer ring detection, since the outer ring can obtain larger reference vibration and induced vibration, the detection sensitivity can be improved. At the same time, the invention subtly embeds the detection electrode and the driving electrode into the inside of the metal multi-ring vibrating disc vibrator, which enhances the compactness of the structure.

According to a second aspect of the present invention, there is provided a method for preparing a metal structure multi-ring vibrating disk micro-gyro, comprising the following steps:

A layer of metal film is deposited on the substrate, and patterned by a photolithographic film to define the arrangement of wires, which is the interconnection layer;

Deposit an insulating layer on the interconnect layer and pattern it by photolithography to open the windows required for subsequent electroplating of metal multi-ring oscillators, electrodes and solder joints;

Sputter a seed layer on the insulating layer to prepare for the subsequent electroplating process;

First, a layer of thin film is electroplated on the seed layer. According to the structural requirements of the metal multi-ring oscillator, the thin film is patterned by photolithography, and finally the smoothing process is performed as the sacrificial layer of the subsequent electroplating process;

Spin-coat photoresist on the sacrificial layer and pattern it;

After the patterning is completed, through the electroplating process, the metal vibrator structure and support column of the metal multi-ring vibrator, the bonding layer of the detection electrode, the driving electrode and the packaging cover are processed at one time, and then the polishing process is carried out to ensure the flatness and symmetry of the surface of the metal vibrator. sex;

After completing the electroplating process of the metal vibrator and the electrode, remove the sacrificial layer; then, remove the redundant seed layer;

Electroplating and encapsulating the bonding metal layer on the top of the encapsulation cover; inserting a vacuum suction device in the encapsulation cover to provide a vacuum and closed environment for the vibration of the vibrator after bonding;

By bonding metal layers and bonding layers, the metal multi-ring vibrator is encapsulated to obtain the metal multi-ring disc vibrating micro gyro.

Compared with the prior art, the present invention has the following beneficial effects:

The metal multi-ring vibrator of the present invention adopts a plane ring structure, which is easy to obtain higher geometric symmetry and quality factor, and the required process cost is also lower.

The vibrator of the present invention adopts a metal structure, which has a higher density compared with silicon, and is processed by an electroplating process, so that it is easier to realize microstructure processing, and the difficulty and relative cost are lower.

The multi-ring structure adopted in the present invention can obtain larger amplitude, thereby achieving larger driving force and better detection sensitivity.

Description of drawings

Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

1 is a cross-sectional view of a metal structure multi-ring vibrating disk micro-gyroscope after packaging according to an embodiment of the present invention;

2 is a top view of a metal multi-ring vibrator and electrodes in an embodiment of the present invention;

3 is a vibration mode diagram of a metal multi-ring vibrator according to an embodiment of the present invention;

4 is a flow chart of a preparation method in an embodiment of the present invention;

In the picture: metal multi-ring vibrator 100, top 200;

Support column 101, drive electrodes 102, 103, detection electrodes 104, 105, spokes 106, metal ring 107, groove 108;

Metal oscillator structure 201 , insulating layers 202 and 203 , interconnection layer 204 , window 205 , vacuum suction device 206 , bonding metal layer 207 , and bonding layer 208 .

Detailed ways

The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

As shown in FIG. 1 , a cross-sectional view of a metal structure multi-ring vibrating disk micro-gyro after packaging, the metal structure multi-ring vibrating disk micro-gyroscope includes a package cover, a metal multi-ring vibrator 100 and a substrate from top to bottom.

The packaging cover provides a vacuum and closed environment for the metal multi-ring vibrator 100 to improve the detection accuracy of the gyroscope.

The metal multi-ring vibrator is used as the main vibration structure, and the object to be detected is built in the vacuum and closed environment formed between the packaging cover and the substrate;

While the substrate acts as a support, it is also responsible for the work of exporting electrodes and other interfaces.

Specifically, the package cover includes a top 200, a bonding metal layer 207 and a vacuum suction device 206 located under the top 200; the vacuum suction device 206 consumes the gas remaining or leaking in the closed environment through chemical reaction to maintain a high vacuum continuously.

The substrate is provided with the bonding layer 208 of the packaging cover and the lead-out solder joints 205 of the interconnection layer. While the substrate is used as a support, it is responsible for the work of exporting the electrode interface; the bonding layer 208 and the bonding metal layer 207 are connected. The bonding forms a vacuum-enclosed space, and the metal multi-ring vibrator 100 is encapsulated in the vacuum-enclosed space; the detection accuracy of the gyro is improved.

As shown in FIG. 2 , which is a top view of the metal multi-ring vibrator 100 , the metal multi-ring vibrator includes a metal vibrator structure 201 and a support column 101 . The supporting column 101 is located in the center of the metal multi-ring vibrator 100 and is drawn out of the package through wires. . The metal vibrator structure 201 is composed of a plurality of concentric metal rings 107, two adjacent metal rings 107 are connected by spokes 106 evenly distributed in the circumferential direction, and the innermost metal ring 107 is connected by the spokes 106, The adjacent metal rings 107 and the spokes 106 partially surround the grooves 108 in the metal multi-ring vibrator 100 , and the formed plurality of grooves 108 are evenly distributed on the metal vibrator structure 201 ;

There is a gap between the metal oscillator structure 201 and the substrate to form a suspended structure. The support column 101 is arranged on the upper surface of the substrate and forms a fixed connection with the substrate. The metal oscillator structure 201 is connected to the support column 101 through the innermost spokes 106 ;

In the metal multi-ring vibrator, several pairs of driving electrodes 102 and 103 are arranged in the groove 108 of the inner ring, and several pairs of detection electrodes 104 and 105 are arranged in the groove 108 of the outer ring. The driving electrodes 102 and 103 and the detection electrodes 104 and 105 It is led out by wires and used for excitation and vibration detection of gyro reference vibration respectively.

The detection electrodes 104, 105 and the drive electrodes 102, 103 can all be metal electrodes.

As shown in FIG. 3, it is the vibration mode diagram of the metal multi-ring vibrator. The specific working principle: when the metal multi-ring vibrator 100 is in a static state (no external angular velocity input), an alternating excitation signal is applied through the driving electrodes 102 and 103. , the vibrator will vibrate in a wine glass shape (the first vibration mode), and the mode shape is transformed between an ellipse and a circle. The horizontal axis in the figure is the vibration axis, which is the maximum amplitude. At this time, the outside world inputs a counterclockwise angular velocity (external rotation angle) to the vibrating gyro vibrator on the plane, and takes a point on the horizontal axis for analysis. The Coriolis effect is shifted upwards. In this phenomenon, due to the conservation of rotation, the gyro generates precession (precession angle), and the angle is θ. Therefore, the vibration mode of the vibrator is offset counterclockwise, and the vibration mode is deflected by a certain angle (the second vibration mode). ).

As shown in Figure 4, it is the preparation flow chart of the above-mentioned micro-gyroscope, which specifically includes the following operation steps:

A: A layer of metal film is deposited on the substrate, and patterned by a photolithographic film to define the arrangement of the wires, that is, the interconnect layer 204 .

B: A layer of insulating layers 202 and 203 is deposited on the interconnect layer 204, and patterned by photolithography to open the windows 205 required for subsequent electroplating of oscillators, electrodes and solder joints.

C: Sputtering a seed layer on the insulating layers 202 and 203 to prepare for the subsequent electroplating process.

D: First, a thin film is electroplated on the seed layer. According to the structural requirements of the vibrator, the thin film is patterned by photolithography, and finally a smoothing process is performed as a sacrificial layer for the subsequent electroplating process.

E: Spin-coat photoresist on the sacrificial layer and pattern it. After completion, through the electroplating process, the metal vibrator structure 201 of the metal multi-ring vibrator, the support column 101, the detection electrodes 104, 105, the driving electrodes 102, 103 and the bonding layer 208 of the package cover are processed at one time, and then the polishing process is performed to ensure that Flatness and symmetry of metal oscillator surfaces.

F: After completing the electroplating process of the metal multi-ring vibrator and the electrode, remove the sacrificial layer.

G: Then, remove the excess seed layer.

H: The package bond metal layer 207 is electroplated on the top 200 of the package lid.

I: A vacuum suction device 206 is built into the package cover to provide a vacuum and closed environment for the vibration of the vibrator after bonding.

J: The metal multi-ring vibrator 100 is encapsulated by bonding the metal layer 207 and the bonding layer 208 to obtain a metal multi-ring disc vibrating micro gyro.

The invention relates to the application of MEMS technology and the MEMS microfabrication process. The invention adopts a plane annular structure, which is easier to implement, has lower processing cost, and can obtain higher quality factor and improve device performance; the metal material has a relatively high relative density, and is processed by electroplating technology, so the processing threshold and cost are lower, And it is easier to realize; the multi-ring structure increases the driving force and detection sensitivity of the micro-gyroscope device. In order to realize this solution, MEMS is mainly used as the etching, deposition and electroplating process in the processing technology, which achieves the purpose of achieving higher device precision and quality with lower cost and conditional requirements.

Embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and those skilled in the art can make various variations or modifications within the scope of the claims, which do not affect the essential content of the present invention.

Claims (7)

1. A metal structure multi-ring vibrating disk micro-gyro, characterized in that: from top to bottom, it comprises a packaging cover, a metal multi-ring vibrator (100) and a substrate, wherein: the packaging cover and the substrate are formed between a vacuum-enclosed space in which the metal multi-ring vibrator (100) is packaged; The metal multi-ring vibrator includes a metal vibrator structure (201) and a support column (101), the supporting column (101) is located in the center of the metal multi-ring vibrator (100), and the metal vibrator structure (201) consists of a plurality of Concentric metal rings (107) are formed, two adjacent metal rings (107) are connected by spokes (106) evenly distributed in the circumferential direction, and the innermost metal ring (107) is connected by the spokes (106) , adjacent metal rings (107) and spokes (106) partially enclose grooves (108) in the metal multi-ring vibrator (100), and the formed multiple grooves (108) are evenly distributed on the metal vibrator structure (201) ; There is a gap between the metal vibrator structure (201) and the substrate to form a suspended structure, the support column (101) is arranged on the upper surface of the substrate, and forms a fixed connection with the substrate, and the metal vibrator structure (201) passes through the innermost spokes (106) is coupled with the support column (101); In the metal multi-ring vibrator, several pairs of driving electrodes (102, 103) are arranged in the groove (108) of the inner ring, and several pairs of detection electrodes (104, 105) are arranged in the groove (108) of the outer ring, and the driving electrodes ( 102, 103) and detection electrodes (104, 105) are respectively used for excitation of gyro reference vibration and detection of vibration. 2. The metal structure multi-ring vibrating disk micro-gyro according to claim 1, wherein the package cover comprises a top (200), and a bonding metal layer (207) and a vacuum located under the top (200) Aspirator (206). 3. The metal structure multi-ring vibrating disk micro-gyro according to claim 2, characterized in that: a bonding layer (208) of a packaging cover is provided on the substrate, and the bonding layer (208) is connected with the key The bonding metal layer (207) is bonded to form a vacuum-enclosed space. 4. The metal structure multi-ring vibrating disc micro-gyro according to claim 1, characterized in that: an interconnection layer (204) is provided on the substrate, and the interconnection layer (204) connects the detection electrodes (104, 105) and the The electrical signals on the drive electrodes (102, 103) are drawn and introduced, the interconnect layer (204) is provided with an insulating layer (202, 203), and the insulating layer (202, 203) is located between the detection electrodes (104, 105) and the drive The bottoms of the electrodes (102, 103) form electrical isolation from surrounding structures. 5. The metal structure multi-ring vibrating disk micro-gyro according to claim 1, characterized in that: the driving electrodes (102, 103) and the detection electrodes (104, 105) are fabricated on the upper surface of the substrate, and are fixed with the substrate coupling. 6. The metal structure multi-ring vibrating disk micro-gyro according to any one of claims 1-5, characterized in that: when the metal multi-ring vibrator (100) is in a static state, the drive electrodes (102, 103) Applying an alternating excitation signal, the metal multi-ring vibrator will generate a reference vibration, that is, the first vibration mode, and the mode shape is transformed between an ellipse and a circle. Input a counterclockwise angular velocity, if a certain point on the metal multi-ring oscillator is moving towards the center of the metal multi-ring oscillator (100), according to the Coriolis effect, the point will be shifted upward by the Coriolis force. Due to the conservation of rotation, the gyroscope will generate a forward motion. The precession angle is θ. Therefore, the vibration mode of the metal multi-ring vibrator has a counterclockwise offset phenomenon, and the vibration mode is deflected by an angle, which is the second vibration mode. 7. the preparation method of the metal structure multi-ring vibrating disk micro-gyroscope described in any one of claim 1-6, it is characterized in that: comprise the steps: A layer of metal film is deposited on the substrate, and patterned by a photolithographic film to define the arrangement of wires, which is an interconnection layer (204); Depositing insulating layers (202, 203) on the interconnect layer (204), and patterning by photolithography, opening windows (205) required for subsequent electroplating of metal multi-ring oscillators, electrodes and solder joints; Sputtering a seed layer on the insulating layers (202, 203) to prepare for the subsequent electroplating process; First, a layer of thin film is electroplated on the seed layer. According to the structural requirements of the metal multi-ring oscillator, the thin film is patterned by photolithography, and finally the smoothing process is performed as the sacrificial layer of the subsequent electroplating process; The photoresist is spin-coated on the sacrificial layer and patterned; after the patterning is completed, the metal vibrator structure (201), the support column (101), and the detection electrode (104) of the metal multi-ring vibrator are processed and formed at one time through the electroplating process. , 105), the driving electrodes (102, 103) and the bonding layer (208) of the package cover, and then perform a smoothing process to ensure the flatness and symmetry of the surface of the metal vibrator; After completing the electroplating process of the metal multi-ring oscillator and the electrode, remove the sacrificial layer; Then, remove the excess seed layer; Electroplating a packaging bonding metal layer (207) on the top (200) of the packaging cover, and inserting a vacuum suction device (206) in the packaging cover (200); By bonding the metal layer (207) and the bonding layer (208), the metal multi-ring vibrator (100) is encapsulated to obtain the metal multi-ring disc vibrating micro gyro.

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