CN104197917B - A kind of Piezoelectric Driving and the micro hemispherical resonator gyro instrument of detection and preparation method thereof - Google Patents

Abstract

The invention provides a piezoelectrically driven and detected miniature hemispherical resonant gyroscope and a preparation method thereof, comprising a single crystal silicon substrate, a central fixed support column, a miniature hemispherical resonator, a common electrode, eight thin-film piezoelectric Body, eight evenly distributed signal electrodes, in which: the single crystal silicon substrate and the micro-hemispheric resonator are connected through the central fixed support column; the common electrode has the same shape as the micro-hemispheric, and is located between the micro-hemispheric resonator and the piezoelectric body; The piezoelectric body has the same shape as the signal electrode, and is located between the common electrode and the signal electrode. The invention adopts piezoelectric driving mode to excite the miniature hemispherical resonator to work, and the driving mode and the detection mode match each other. The invention combines MEMS body silicon processing technology and surface silicon processing technology to make. The invention utilizes the inverse piezoelectric effect and the piezoelectric effect to drive and detect the micro gyroscope, and has the characteristics of high degree of integration, low power consumption, convenient batch production and the like.

Description

A piezoelectric driven and detected miniature hemispherical resonant gyroscope and its preparation method

technical field

The invention relates to a hemispherical resonant gyroscope in the field of micro-electromechanical technology, in particular to a piezoelectrically driven and detected micro hemispherical resonant gyroscope and a preparation method thereof.

Background technique

Gyroscope is an inertial device that can detect the angle or angular velocity of the carrier, and it plays a very important role in the fields of attitude control, navigation and positioning. With the development of national defense technology and aviation and aerospace industries, the requirements of inertial navigation systems for gyroscopes are also developing in the direction of low cost, small size, high precision, multi-axis detection, high reliability, and adaptability to various harsh environments. Therefore, the importance of MEMS gyroscope is self-evident. In particular, as an important research direction of MEMS gyroscopes, micro-resonant gyroscopes have become a research hotspot in this field.

The hemispherical resonant gyroscope uses a hemispherical resonator for detection. There are no high-speed rotating parts, and the stability of the material and the symmetry of the structure make it have many outstanding advantages. It is the most precise mechanical vibration gyroscope at present.

After searching the literature of the prior art, it was found that the US patent "VIBRATORY ROTATION SENSOR" (patent number: 4951508) introduced the principle and signal detection method of the hemispherical resonant gyroscope in detail, which has guiding significance for the research of the hemispherical resonant gyroscope. However, the above-mentioned gyroscope is a traditional hemispherical resonant gyroscope, and its size is relatively large, which limits its application range. The micro hemispherical resonant gyroscope based on MEMS technology inherits the advantages of the traditional hemispherical resonant gyroscope, and also has the advantages of small size, low power consumption and mass production, which has important research value. At present, the common miniature hemispherical resonant gyroscope adopts electrostatic drive and capacitance detection. This driving method needs to make a small-sized capacitance gap and apply a high-amplitude DC bias to provide sufficient driving force; this detection method requires Micro-sized capacitive gaps are made to improve detection accuracy; gyroscopes driven and sensed using this method are susceptible to parasitic capacitance.

Based on this, it is urgent to propose a new gyroscope structure to avoid or reduce the above-mentioned influencing factors and expand its application range at the same time.

Contents of the invention

In view of the defects in the prior art, the purpose of the present invention is to provide a piezoelectrically driven and detected micro-hemispherical resonant gyroscope and its preparation method, without the need to make a small-sized capacitance gap, and without applying a high-amplitude DC bias, At the same time, the influence of parasitic capacitance can be avoided.

According to one aspect of the present invention, there is provided a piezoelectric driven and detected miniature hemispherical resonant gyroscope, comprising:

a single crystal silicon substrate;

A miniature hemispherical harmonic oscillator;

A central fixed support column that fixes and supports the miniature hemispherical resonator;

a common electrode;

Eight thin-film piezoelectric bodies evenly distributed on the common electrode;

Eight evenly distributed signal electrodes;

Among them, the single crystal silicon substrate and the micro-hemispherical resonator are connected through a central fixed support column; the common electrode has the same shape as the micro-hemispherical resonator, and is located between the micro-hemispherical resonator and the thin-film piezoelectric body; the thin-film piezoelectric body and the The signal electrodes have the same shape and are located between the common electrode and the signal electrodes.

The gyroscope excites the miniature hemispherical resonator to work in a piezoelectric driving manner, and the driving mode and the detection mode match each other. The gyroscope uses the inverse piezoelectric effect and the piezoelectric effect to drive and detect the micro gyroscope. Compared with the commonly used electrostatic drive and capacitance detection, there is no need to make a small-sized capacitance gap, and no need to apply a high-amplitude DC bias , At the same time, it can avoid the influence of parasitic capacitance, and has the characteristics of high degree of integration, low power consumption, and convenient mass production.

According to another aspect of the present invention, a kind of preparation method of the miniature hemispherical resonant gyroscope of piezoelectric drive and detection is provided, and described method comprises the steps:

The first step is to clean the single crystal silicon substrate, apply glue, photolithography, development, sputter mask layer, deglue, isotropic etching, and remove the mask layer on the single crystal silicon substrate. A hemispherical groove is obtained on the silicon substrate;

In the second step, on the basis of the first step, the thermal oxidation method is used to grow the silicon dioxide layer, apply glue, photolithography, develop, and partially etch the silicon dioxide layer to obtain a silicon dioxide sacrificial layer with circular grooves;

The third step is to deposit non-doped polysilicon or non-doped diamond on the basis of the second step, and remove the polysilicon or diamond outside the hemispherical groove by chemical mechanical polishing to obtain a hemispherical structure layer with support columns;

The fourth step is to sputter metal aluminum or metal molybdenum on the basis of the third step, apply glue, photolithography, develop, etch, remove metal aluminum or metal molybdenum other than the hemispherical groove, and obtain a hemispherical common electrode;

The fifth step, sputtering aluminum nitride or PZT film on the basis of the fourth step to obtain a piezoelectric film layer;

The sixth step is to sputter metal aluminum or metal molybdenum on the basis of the fifth step to obtain the signal electrode layer;

The seventh step is to apply glue, photolithography, and development on the basis of the sixth step, and etch the signal electrode layer to obtain the patterned signal electrode layer and evenly distributed signal electrodes;

The eighth step, on the basis of the seventh step, the signal electrode is used as a mask to etch the piezoelectric thin film layer to obtain a uniformly distributed thin film piezoelectric body;

In the ninth step, on the basis of the eighth step, the silicon dioxide sacrificial layer is etched with a BHF solution, and the micro hemispherical resonator is released from the single crystal silicon substrate.

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

(1) The gyroscope is made in combination with the MEMS bulk silicon processing technology and the surface silicon processing technology, which is a novel processing technology;

(2) The gyroscope does not need to make a small-sized capacitance gap, and does not need to apply a high-amplitude DC bias, which reduces processing requirements and energy consumption requirements;

(3) The gyroscope can avoid the influence of parasitic capacitance and improve the accuracy of detection.

Description of drawings

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

Fig. 1 (a)-Fig. 1 (i) is the preparation flowchart of a preferred embodiment of the present invention;

Fig. 2 (a), Fig. 2 (b) are the three-dimensional structural diagram and top view thereof of a preferred embodiment of the present invention;

In the figure: 1 is a single crystal silicon substrate, 2 is a central fixed support column, 3 is a micro hemispherical resonator, 4 is a common electrode, 5 is a thin-film piezoelectric body, and 6 is a signal electrode.

detailed description

The present invention will be described in detail below in conjunction with 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 those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

Example 1

As shown in Figure 2(a) and Figure 2(b), the present embodiment provides a piezoelectrically driven and detected miniature hemispherical resonant gyroscope, including:

a single crystal silicon substrate 1;

a central fixed support column 2;

A miniature hemispherical harmonic oscillator 3;

a common electrode 4;

Eight thin-film piezoelectric bodies 5;

Eight evenly distributed signal electrodes 6;

Among them, the single crystal silicon substrate 1 and the micro-hemispherical resonator 3 are connected through the central fixed support column 2; the common electrode 4 has the same shape as the micro-hemispherical resonator 3, and is located between the micro-hemispherical resonator 3 and the thin-film piezoelectric body 5; The thin-film piezoelectric body 5 has the same shape as the signal electrode 6 and is located between the common electrode 4 and the signal electrode 6 .

In this embodiment, the material of the central fixed support pillar 2 is non-doped polysilicon or non-doped diamond, which is used to fix and support the micro-hemispherical resonator 3 .

In this embodiment, the material of the miniature hemispherical resonator 3 is the same as that of the central fixed support pillar 2, which is non-doped polysilicon or non-doped diamond, which is the main carrier of the driving mode and the detection mode.

In this embodiment, the material of the common electrode 4 is metal aluminum or metal molybdenum, which provides the same ground signal for different thin-film piezoelectric bodies 5 .

In this embodiment, the material of the thin-film piezoelectric body 5 is aluminum nitride or lead zirconate titanate (PZT), which is evenly distributed on the common electrode 4 . The thin-film piezoelectric body 5 is divided into a driving piezoelectric body and a detection piezoelectric body, both of which have the same shape and are distributed at intervals. The driving piezoelectric body provides driving force for the miniature hemispherical resonator 3, and the detection piezoelectric body The detection signal is formed by the micro-hemispheric resonator 3 .

In this embodiment, the material of the signal electrode 6 is the same as that of the common electrode 4 , which is metal aluminum or metal molybdenum. The signal electrode 6 is divided into a driving electrode and a detection electrode. The driving electrode is located on the driving piezoelectric body, and the detection electrode is located on the detection piezoelectric body. The driving electrode provides a driving signal for the driving piezoelectric body. The piezoelectric body extracts the detection signal.

In this embodiment, a driving voltage is applied to the driving electrodes in the signal electrodes 6 of the micro-hemispheric resonant gyroscope, and a ground signal is applied to the common electrode 4, so that The two sides of the driving piezoelectric body form a potential difference, and the micro hemispherical resonator 3 works in the required driving mode through the inverse piezoelectric effect, and the vibration amplitude and frequency of the driving mode remain unchanged; when perpendicular to When there is an external angular velocity in the direction of the substrate, the vibration amplitude of the detection mode will change, and cause the same vibration of the detection piezoelectric body in the film piezoelectric body 5, and the vibration amplitude of the detection piezoelectric body The magnitude of the vibration amplitude is proportional to the magnitude of the applied angular velocity, and the magnitude of the vibration amplitude can be detected on the detection electrode in the signal electrode 6 through the piezoelectric effect, and the magnitude of the applied angular velocity can be calculated.

Example 2

As shown in Figure 1 (a)-Figure 1 (i), the present embodiment provides a kind of preparation method of the miniature hemispherical resonant gyroscope of described piezoelectric drive and detection, comprises the following steps:

The first step, as shown in Fig. 1(a), is to clean the single crystal silicon substrate 1, apply glue on the single crystal silicon substrate 1, perform photolithography, development, sputtering mask layer, glue removal, and isotropic Etching and removing the mask layer to obtain a hemispherical groove with a radius of 300-700 μm on the single crystal silicon substrate 1;

In the second step, as shown in Figure 1(b), on the basis of the first step, the thermal oxidation method is used to grow the silicon dioxide layer, glue coating, photolithography, development, and partial etching of the silicon dioxide layer to obtain a radius SiO2 sacrificial layer for 15-40 μm circular grooves;

The third step, as shown in Figure 1(c), deposits non-doped polysilicon or non-doped diamond on the basis of the second step, and removes the polysilicon or diamond outside the hemispherical groove by chemical mechanical polishing, and obtains a The hemispherical structural layer of the support column with a thickness of 1-5 μm;

The fourth step, as shown in Figure 1(d), sputters metal aluminum or metal molybdenum on the basis of the third step, coating, photolithography, development, etching, and removes metal aluminum or metal other than the hemispherical groove molybdenum to obtain a hemispherical common electrode 4 with a thickness of 1-5 μm;

The fifth step, as shown in Figure 1(e), sputters aluminum nitride or PZT film on the basis of the fourth step to obtain a piezoelectric film layer with a thickness of 0.5-3.5 μm;

The sixth step, as shown in Figure 1(f), sputters metal aluminum or metal molybdenum on the basis of the fifth step to obtain a signal electrode layer with a thickness of 0.5-3.5 μm;

The seventh step, as shown in Figure 1(g), on the basis of the sixth step, apply glue, photolithography, and development, and etch the signal electrode layer to obtain a patterned signal electrode layer and evenly distributed signal electrodes 6;

The eighth step, as shown in Figure 1(h), on the basis of the seventh step, the signal electrode 6 is used as a mask to etch the piezoelectric thin film layer to obtain a uniformly distributed thin film piezoelectric body 5;

In the ninth step, as shown in FIG. 1(i), on the basis of the eighth step, the silicon dioxide sacrificial layer is etched with BHF solution, and the micro hemispherical resonator 3 is released from the single crystal silicon substrate 1 .

The gyroscope described in this embodiment excites the micro-hemispheric resonator 3 to work by means of piezoelectric driving, and its driving mode and detection mode match each other respectively.

Example 3

Basically the same as embodiment 1 and embodiment 2, the difference is:

The gyroscope prepared in this embodiment: the materials of the central fixed support column 2 and the micro-hemispherical resonator 3 are doped polysilicon or doped diamond, and the micro-hemispherical resonator 3 simultaneously serves as the micro-hemispherical resonator 3 and common electrode 4, no need to make additional common electrode 4;

Therefore, the third step in the preparation method of this embodiment: deposit doped polysilicon or doped diamond on the basis of the second step; remove the fourth step in the preparation method described in Example 2, and directly proceed from the fifth step to the first step nine steps. Other operations are the same as in Example 2.

The gyroscope in the present invention is manufactured by combining MEMS bulk silicon processing technology and surface silicon processing technology, which is a novel processing technology.

The present invention utilizes the inverse piezoelectric effect and the piezoelectric effect to drive and detect the micro-gyroscope. Compared with the commonly used electrostatic drive and capacitance detection, it does not need to make a small-sized capacitance gap, and does not need to apply a high-amplitude DC bias. Reduce processing requirements and energy consumption requirements;

The gyroscope in the invention can avoid the influence of parasitic capacitance and improve the accuracy of detection.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims (11)

1. A preparation method of a piezoelectrically driven and detected miniature hemispherical resonant gyroscope, characterized in that, The piezoelectrically driven and detected miniature hemispherical resonant gyroscope includes: a single crystal silicon substrate; A miniature hemispherical harmonic oscillator; A central fixed support column that fixes and supports the miniature hemispherical resonator; a common electrode; Eight thin-film piezoelectric bodies evenly distributed on the common electrode; Eight evenly distributed signal electrodes; Among them, the single crystal silicon substrate and the micro-hemispherical resonator are connected through a central fixed support column; the common electrode has the same shape as the micro-hemispherical resonator, and is located between the micro-hemispherical resonator and the thin-film piezoelectric body; the thin-film piezoelectric body and the The signal electrodes have the same shape and are located between the common electrode and the signal electrode; The method comprises the steps of: The first step is to clean the single crystal silicon substrate, apply glue, photolithography, development, sputter mask layer, deglue, isotropic etching, and remove the mask layer on the single crystal silicon substrate. A hemispherical groove is obtained on the silicon substrate; In the second step, on the basis of the first step, the thermal oxidation method is used to grow the silicon dioxide layer, apply glue, photolithography, develop, and partially etch the silicon dioxide layer to obtain a silicon dioxide sacrificial layer with circular grooves; The third step is to deposit non-doped polysilicon or non-doped diamond on the basis of the second step, and remove the polysilicon or diamond outside the hemispherical groove by chemical mechanical polishing to obtain a hemispherical structure layer with support columns; The fourth step is to sputter metal aluminum or metal molybdenum on the basis of the third step, apply glue, photolithography, develop, etch, remove metal aluminum or metal molybdenum other than the hemispherical groove, and obtain a hemispherical common electrode; The fifth step, sputtering aluminum nitride or PZT film on the basis of the fourth step to obtain a piezoelectric film layer; The sixth step is to sputter metal aluminum or metal molybdenum on the basis of the fifth step to obtain the signal electrode layer; The seventh step is to apply glue, photolithography, and development on the basis of the sixth step, and etch the signal electrode layer to obtain the patterned signal electrode layer and evenly distributed signal electrodes; The eighth step, on the basis of the seventh step, the signal electrode is used as a mask to etch the piezoelectric thin film layer to obtain a uniformly distributed thin film piezoelectric body; In the ninth step, on the basis of the eighth step, the silicon dioxide sacrificial layer is etched with a BHF solution, and the micro hemispherical resonator is released from the single crystal silicon substrate. 2. the preparation method of the miniature hemispherical resonator gyroscope driven by piezoelectricity and detection according to claim 1, is characterized in that, in the first step, the radius of the described hemispherical groove that obtains on single crystal silicon substrate is 300-700μm. 3. the preparation method of the miniature hemispherical resonant gyroscope driven by piezoelectricity and detection according to claim 1, is characterized in that, in the second step, the radius of the circular groove obtained on the silicon dioxide sacrificial layer 15-40μm. 4. the preparation method of the miniature hemispherical resonant gyroscope driven by piezoelectricity and detection according to claim 1, is characterized in that, in the third step, the thickness of the described hemispherical structure layer with supporting pillars is 1-5 μm . 5 . The method for manufacturing a piezoelectrically driven and detected micro hemispherical resonant gyroscope according to claim 1 , wherein in the fourth step, the thickness of the hemispherical common electrode is 0.5-3.5 μm. 6 . The method for manufacturing a piezoelectrically driven and detected micro-hemispheric resonant gyroscope according to claim 1 , wherein in the fifth step, the thickness of the piezoelectric film layer is 0.5-3.5 μm. 7 . The method for manufacturing a piezoelectrically driven and detected micro hemispherical resonant gyroscope according to claim 1 , wherein in the sixth step, the thickness of the signal electrode layer is 0.5-3.5 μm. 8. The preparation method of the piezoelectrically driven and detected miniature hemispherical resonator gyroscope according to any one of claims 1-7, characterized in that, the material of the central fixed support column and the described miniature hemispherical resonator For doping polysilicon or doping diamond, the micro-hemispheric resonator serves as the micro-hemispheric resonator and the common electrode at the same time, and no additional common electrode is required; at this time, the third step is to deposit doped polysilicon or doped on the basis of the second step. For diamond, omit the fourth step. 9. The preparation method of the piezoelectrically driven and detected miniature hemispherical resonant gyroscope according to any one of claims 1-7, wherein the thin-film piezoelectric body is divided into a driving piezoelectric body and a detection piezoelectric body. The two bodies have the same shape and are distributed at intervals, wherein: the driving piezoelectric body provides driving force for the miniature hemispherical resonator, and the detection piezoelectric body forms a detection signal through the micro hemispherical resonator. 10. according to the preparation method of the miniature hemispherical resonant gyroscope that piezoelectricity drives and detects according to any one of claim 1-7, it is characterized in that, described common electrode provides identical ground signal for different thin-film piezoelectric bodies; The signal electrode is divided into a driving electrode and a detection electrode, and the driving electrode is located on the driving piezoelectric body and provides a driving signal for the driving piezoelectric body; the detection electrode is located on the detection piezoelectric body and extracts a detection electrode from the detection piezoelectric body. Signal. 11. The preparation method of the piezoelectrically driven and detected miniature hemispherical resonator gyroscope according to any one of claims 1-7, wherein the material of the thin-film piezoelectric body is aluminum nitride or zirconate titanic acid lead; the materials of the common electrode and the signal electrode are metal aluminum or metal molybdenum.