Micro-hemispherical electrode and preparation method thereof, and micro-hemispherical resonant gyroscope

Abstract

The present invention discloses a micro-hemispherical electrode, a method for fabricating the same, and a micro-hemispherical resonant gyroscope. The fabrication method comprises: forming a high-voltage film layer and a metal base film layer on a quartz surface, the two being separated by a base pattern having a predetermined line width; forming an insulating film layer having a ring-shaped main structure on the high-voltage film layer; and forming multiple electrode film layers and a grounding device (GND) film layer on the insulating film layer and the metal base film layer. The multiple electrode film layers are located on the insulating layer and are circumferentially spaced about the high-voltage film layer enclosed by an inner ring of the insulating layer. The electrode film layers and the grounding device (GND) film layer are separated by a frame pattern having a predetermined line width, and the grounding device (GND) film layer extends inward from the edge of the quartz surface to the inner ring near the insulating layer. The present invention can effectively alleviate the problems of signal instability and circuit board short-circuit damage caused by uneven electric fields in micro-hemispherical resonant gyroscopes.

Description

Technical Field

[0001] The present invention relates to the field of inertial navigation technology, and in particular to a micro-hemispherical electrode and a preparation method thereof, and a micro-hemispherical resonant gyroscope. Background Art

[0002] The micro-hemispherical resonator gyroscope is a primary inertial sensing element in small attitude measurement systems. Compared to traditional MEMS gyroscopes, the measurement accuracy of the micro-hemispherical resonator gyroscope can achieve inertial navigation-level attitude measurement, making it more suitable for use in high-precision scenarios such as mimic games, small drones, and intelligent robots. The core components of the micro-hemispherical resonator gyroscope are composed of a micro-hemispherical resonator and a drive electrode. The micro-hemispherical resonator is a solid-state resonator made of quartz glass. Its working principle of sensing attitude angle requires electrical signal detection. The input and output electrodes of the electrical signal are also made of quartz with the same performance. Quartz is an insulator, so a layer of metal conductive film must be prepared on its surface to stimulate and detect through capacitive electrostatic force.

[0003] According to the excitation method of the micro-hemispherical resonator, it can be divided into a planar base electrode and a spherical base electrode. Compared with the spherical base electrode, which needs to match the curvature of the micro-hemispherical resonator, the planar base electrode only needs to ensure the flatness. Therefore, in terms of processing capacity and cost, the planar electrode is more suitable for the manufacture of micro-hemispherical resonator gyroscopes. The planar base electrode is mainly used for excitation by forming a capacitor with the equatorial plane of the micro-hemispherical resonator and the planar electrode to resonate and measure. The planar electrode is limited by the size of the micro-hemispherical resonator. Each electrode separation insulation line is relatively small, and the micro-hemispherical resonator is bowl-shaped with a protruding anchor rod in the center. The electrode surface integrates high voltage, GND, excitation and detection electrodes. The high voltage needs to be connected to the center anchor column, such as Figure 1 As shown, the high-voltage circuit needs to pass through the planar electrode plate below the micro-hemispherical resonant equatorial plane. Specifically, the central anchor column is electrically connected to the center position of the electrode plate, and the high-voltage signal is introduced from the edge position of the electrode plate surface through the gap between two adjacent electrodes 100 into the high-voltage area 200 at the center position. However, the interval between the micro-hemispherical resonant equatorial plane and the planar electrode is only 5-20 μm, and when high voltage is energized, the surface contamination of the membrane layer and structural defects such as inconsistent channel widths for introducing high voltage in various directions will lead to an increase in local electric field strength, making the electric field in various directions uneven. The uneven surface charge will cause vibration modal distortion, affecting the angular velocity detection accuracy, and long-term high voltage will cause charge injection into the quartz base, affecting long-term stability. In addition, the distance between the high-voltage electrode channel and the resonator is too small, which is prone to dielectric breakdown, causing a short circuit and damaging the membrane layer or the circuit board. Summary of the Invention

[0004] In response to the problems in the background technology, the present invention proposes a micro-hemispherical electrode and a preparation method thereof, which can effectively improve the signal instability and circuit board short-circuit damage problems caused by the uneven electric field of the micro-hemispherical resonant gyroscope. A micro-hemispherical resonant gyroscope including the micro-hemispherical electrode is also provided.

[0005] The present invention adopts the following technical solutions:

[0006] A method for preparing a micro-hemispherical electrode, comprising:

[0007] S1: performing film formation on the quartz surface to form a high-pressure film layer and a metal base film layer. The high-pressure film layer and the metal base film layer are separated by a bottom pattern with a set line width. The bottom pattern includes a large circle located at the center of the quartz surface and a small circle located at a diagonal position of the quartz surface. The large circle and the small circle are connected. The high-pressure film layer covers the area enclosed by the large circle and the small circle on the quartz surface. The metal base film layer covers the area of ​​the quartz surface except the area enclosed by the large circle and the small circle.

[0008] S2: performing film forming processing on the high-voltage film layer to form an insulating film layer with a main ring structure, wherein the insulating film layer covers an area of ​​the high-voltage film layer corresponding to an edge area of ​​the large circle, and an area corresponding to a connecting area between the large circle and the small circle;

[0009] S3: Film forming is performed on the insulating film layer and the metal base film layer to form multiple electrode film layers and GND film layers. The multiple electrode film layers are located on the insulating layer and are circumferentially spaced around the high-voltage film layer surrounded by the inner ring of the insulating layer. The electrode film layer and the GND film layer are separated by a frame pattern with a set line width. The GND film layer extends inward from the edge of the quartz surface to the inner ring close to the insulating layer.

[0010] Optionally, the specific process of step S1 is as follows:

[0011] S1.1: Spray photoresist on the quartz surface and remove the photoresist except the bottom pattern on the quartz surface;

[0012] S1.2: Plating a first metal film layer on the quartz surface, and then removing the bottom pattern to obtain a high-voltage film layer and a metal bottom film layer.

[0013] Optionally, the first metal film layer includes a first base film layer and a first functional film layer provided on the first base film layer. The first base film layer is made of Cr and / or Ti, and the first functional film layer is made of Au, Pt and / or Ag.

[0014] Optionally, the specific process of step S2 is as follows:

[0015] S2.1: Spray photoresist on the quartz surface and remove the photoresist at the position corresponding to the quartz surface and the insulating film layer;

[0016] S2.2: Coating an insulating film layer on the quartz surface and then removing the photoresist on the quartz surface.

[0017] Optionally, the insulating film layer is made of porous SiO2 or Si3N4.

[0018] Optionally, the specific process of step S3 is as follows:

[0019] S3.1: Spraying photoresist on the quartz surface to remove the photoresist except for the top pattern on the quartz surface; the top pattern includes a middle circle, a plurality of frames, and the small circles; the middle circle extends outward from the center of the quartz surface to cover a portion of the insulating film layer; the plurality of frames are circumferentially spaced about the middle circle;

[0020] S3.2: A second metal film layer is plated on the quartz surface, and then the top layer pattern is removed to obtain multiple electrode film layers and a GND film layer.

[0021] Optionally, the second metal film layer includes a second base film layer and a second functional film layer provided on the second base film layer, the second base film layer is made of Cr and / or Ti, and the second functional film layer is made of Au, Pt and / or Ag.

[0022] Optionally, the thickness of the first base film layer is 50nm-200nm, the thickness of the first functional film layer is 500nm-2μm, the thickness of the insulating film layer is 1μm-2μm, the thickness of the second base film layer is 50nm-200nm, and the thickness of the second functional film layer is 500nm-2μm.

[0023] As a general inventive concept, the present invention also provides a micro-hemispherical electrode prepared by the above-mentioned preparation method.

[0024] As a general inventive concept, the present invention also provides a micro-hemispherical resonant gyroscope, including a micro-hemispherical resonator and a micro-hemispherical electrode prepared by the above-mentioned preparation method, wherein the central rod of the micro-hemispherical resonator is bonded to the high-voltage film layer at the center position of the surface of the micro-hemispherical electrode, and the lip edge of the micro-hemispherical resonator and the electrode film layer on the surface of the micro-hemispherical electrode constitute a detection or excitation capacitor.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] The micro-hemispherical electrode prepared by the present invention consists of a bottom high-voltage film layer, a middle insulating film layer, and a top electrode film layer and a GND film layer. The bottom high-voltage film layer is flatly laid on the quartz surface. The flat design can ensure temperature stability and modal purity, so it will not affect the angular velocity detection accuracy. In addition, since there is no electric field unevenness, the non-uniform electrostatic force is offset and the gyroscope drift is reduced. There is a height difference between the bottom high-voltage film layer and the top electrode film layer, and they are separated by the middle insulating film layer. On the one hand, the distance between the high-voltage electrode channel and the resonator is relatively increased, and the dielectric breakdown effect is greatly reduced. On the other hand, the high-voltage film layer and the electrode film layer are separated by the insulating film layer to avoid short circuit, ensure system safety, and solve the problem of parasitic capacitance coupling noise generated by the coplanarity of the high-voltage electrode and the electrode film layer. The insulating layer isolates the high voltage from the sensitive signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to make the present invention more easily understood, the present invention will be described in more detail with reference to the specific embodiments shown in the accompanying drawings. These drawings only depict typical embodiments of the present invention and should not be considered as limiting the scope of protection of the present invention.

[0028] Figure 1 A plan view of a micro-hemispherical electrode in the prior art.

[0029] Figure 2 Schematic diagram of forming a bottom layer pattern on a quartz surface according to Example 1 of the present invention.

[0030] Figure 3 This is a schematic diagram of the first metal film layer coated on the quartz surface in Example 1 of the present invention.

[0031] Figure 4 Schematic diagram of forming a middle layer pattern on a quartz surface according to Example 1 of the present invention.

[0032] Figure 5 This is a schematic diagram of the quartz surface after an insulating film layer is plated according to Example 1 of the present invention.

[0033] Figure 6 Schematic diagram of forming a top layer pattern on a quartz surface according to Example 1 of the present invention.

[0034] Figure 7 This is a schematic diagram of the second metal film layer coated on the quartz surface according to Example 1 of the present invention.

[0035] Figure 8 This is a longitudinal cross-sectional view of the micro-hemispherical electrode of Example 1 of the present invention.

[0036] Figure 9 This is a longitudinal cross-sectional view of the micro-hemispherical resonant gyroscope according to Example 2 of the present invention.

[0037] Reference numerals:

[0038] 1-high-voltage film layer, 2-metal bottom film layer, 3-electrode film layer, 4-insulating film layer, 5-bottom layer pattern, 6-middle layer pattern, 7-GND film layer, 8-top layer pattern, 9-quartz plate, 10-micro-hemispherical electrode, 20-micro-hemispherical resonator, 21-center rod, 22-lip edge. DETAILED DESCRIPTION

[0039] The following describes the embodiments of the present invention with reference to the accompanying drawings so that those skilled in the art can better understand the present invention and implement it. However, the enumerated embodiments are not intended to limit the present invention. Unless there is a conflict, the following embodiments and the technical features in the embodiments can be combined with each other, wherein the same components are represented by the same figure marks.

[0040] Example 1:

[0041] This embodiment provides a method for preparing a micro-hemispherical electrode, comprising:

[0042] S1: performing film formation on the quartz surface to form a high-pressure film layer and a metal base film layer. The high-pressure film layer and the metal base film layer are separated by a bottom pattern with a set line width. The bottom pattern includes a large circle located at the center of the quartz surface and a small circle located at a diagonal position of the quartz surface. The large circle and the small circle are connected. The high-pressure film layer covers the area enclosed by the large circle and the small circle on the quartz surface. The metal base film layer covers the area of ​​the quartz surface except the area enclosed by the large circle and the small circle.

[0043] Specifically, the specific process of step S1 is as follows:

[0044] S1.1: Spray photoresist on the entire surface of a square quartz plate 9 with a length and width of 8-10 mm and a thickness of 2-5 mm, remove the photoresist on the quartz surface except for the bottom pattern 5 and clean it. Figure 2 As shown;

[0045] S1.2: A first metal film layer is deposited on the quartz surface by magnetron sputtering, and then the photoresist at the bottom pattern 5 on the quartz surface is removed to obtain a high-voltage film layer 1 and a metal bottom film layer 2 separated by the bottom pattern, as shown in FIG. Figure 3 shown.

[0046] In this embodiment, the first metal film layer includes a first base film layer and a first functional film layer provided on the first base film layer. The material of the first base film layer is Cr and / or Ti which have good bonding with quartz, and has a thickness of 50nm-200nm; the material of the first functional film layer is selected from Au, Pt and / or Ag with stable performance, and has a thickness of 500nm-2μm.

[0047] S2: performing film forming processing on the high-voltage film layer to form an insulating film layer with a main ring structure, wherein the insulating film layer covers an area of ​​the high-voltage film layer corresponding to an edge area of ​​the large circle, and an area corresponding to a connecting area between the large circle and the small circle;

[0048] Specifically, the specific process of step S2 is as follows:

[0049] S2.1: spraying photoresist on the entire surface of the quartz surface by spraying, removing the photoresist except the middle pattern 6 on the quartz surface and cleaning it. The middle pattern 6 is specifically a pattern composed of other areas on the quartz surface except the area corresponding to the insulating film layer, such as Figure 4 As shown;

[0050] S2.2: Using a magnetron sputtering coating method, an insulating film layer 4 is coated on the quartz surface, and then the photoresist located at the middle layer pattern 6 on the quartz surface is removed, such as Figure 5 shown.

[0051] In this embodiment, the insulating film layer is made of porous SiO2 or Si3N4, and has a thickness of 1 μm-2 μm.

[0052] S3: Film forming is performed on the insulating film layer and the metal base film layer to form multiple electrode film layers and GND film layers. The multiple electrode film layers are located on the insulating layer and are circumferentially spaced around the high-voltage film layer surrounded by the inner ring of the insulating layer. The electrode film layer and the GND film layer are separated by a frame pattern with a set line width. The GND film layer extends inward from the edge of the quartz surface to the inner ring close to the insulating layer.

[0053] Specifically, the specific process of step S3 is as follows:

[0054] S3.1: Spray photoresist on the entire surface of the quartz surface by spraying, and remove the photoresist on the quartz surface except for the top pattern 8; the top pattern 8 includes a middle circle, multiple frames and the small circle. In this embodiment, the top pattern 8 also includes a connecting channel between the large circle and the small circle. The middle circle extends outward from the center of the quartz surface to cover part of the insulating film layer 4. The multiple frames are circumferentially spaced around the middle circle, as shown in FIG. Figure 6 As shown;

[0055] S3.2: A second metal film layer is deposited on the quartz surface by magnetron sputtering, and then the photoresist at the top pattern 8 is removed to obtain multiple electrode film layers 3 and a GND film layer 7, as shown in FIG. Figure 7 shown.

[0056] In other embodiments, the connection channel between the large circle and the small circle may not be masked, and plating the second metal film layer here has little effect on the performance.

[0057] In this embodiment, the second metal film layer includes a second base film layer and a second functional film layer arranged on the second base film layer. The material of the second base film layer is Cr and / or Ti, and the thickness is 50nm-200nm. The material of the second functional film layer is Au, Pt and / or Ag, and the thickness is 500nm-2μm.

[0058] like Figure 8 This is a longitudinal cross-section of the micro-hemispherical electrode produced in this embodiment. The bottom high-voltage film layer 1 and the top second metal film layer are separated by an intermediate insulating film layer 4. The GND film layer 7 extends only close to the insulating film layer 4 but does not completely cover it, ensuring a more secure separation between the bottom high-voltage film layer 1 and the top second metal film layer. The top GND film layer 7 and the electrode film layer 3 are separated by a top pattern 8. The GND film layer 7 surrounds the lead-out area of ​​the electrode film layer 3 and the high-voltage film layer 1 (i.e., the small circle at the edge of the quartz plate), facilitating ground connections.

[0059] The bottom high-voltage film layer 1 is laid flat on the quartz surface. The flat design can ensure temperature stability and modal purity, so it will not affect the angular velocity detection accuracy. In addition, since there is no electric field unevenness, the non-uniform electrostatic force is offset and the gyroscope drift is reduced. There is a height difference between the bottom high-voltage film layer 1 and the top electrode film layer 3, and they are separated by the middle insulating film layer 4. On the one hand, the distance between the high-voltage electrode channel and the resonator is relatively increased, and the dielectric breakdown effect is greatly reduced. On the other hand, the high-voltage film layer 1 and the electrode film layer 3 are separated by the insulating film layer 4 to avoid short circuit, ensure system safety, and solve the problem of parasitic capacitance coupling noise generated by the coplanarity of the high-voltage electrode and the electrode film layer 3. The insulating film layer 4 isolates the high voltage from the sensitive signal.

[0060] Example 2:

[0061] like Figure 9 As shown, this embodiment provides a micro-hemispherical resonator gyroscope, including a micro-hemispherical resonator 20 and a micro-hemispherical electrode 10 prepared in Example 1. The central rod 21 of the micro-hemispherical resonator 20 is bonded to the high-voltage film layer 1 at the center position of the surface of the micro-hemispherical electrode 10. The lip edge 22 of the micro-hemispherical resonator 20 and the electrode film layer 3 on the surface of the micro-hemispherical electrode 20 form a detection or excitation capacitor.

[0062] The embodiments described above are merely preferred embodiments of the present invention. The phrases "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments" used in this specification may refer to one or more of the same or different embodiments of the present disclosure. Any common changes and substitutions made by those skilled in the art within the scope of the present invention are intended to be encompassed within the scope of protection of the present invention.

Claims

1. A method for preparing a micro-hemispherical electrode, characterized in that: include: S1: performing film formation on the quartz surface to form a high-pressure film layer and a metal base film layer. The high-pressure film layer and the metal base film layer are separated by a bottom pattern with a set line width. The bottom pattern includes a large circle located at the center of the quartz surface and a small circle located at a diagonal position of the quartz surface. The large circle and the small circle are connected. The high-pressure film layer covers the area enclosed by the large circle and the small circle on the quartz surface. The metal base film layer covers the area of ​​the quartz surface except the area enclosed by the large circle and the small circle. S2: performing film forming processing on the high-voltage film layer to form an insulating film layer with a main ring structure, wherein the insulating film layer covers an area of ​​the high-voltage film layer corresponding to an edge area of ​​the large circle, and an area corresponding to a connecting area between the large circle and the small circle; S3: Film forming is performed on the insulating film layer and the metal base film layer to form multiple electrode film layers and GND film layers. The multiple electrode film layers are located on the insulating layer and are circumferentially spaced around the high-voltage film layer surrounded by the inner ring of the insulating layer. The electrode film layer and the GND film layer are separated by a frame pattern with a set line width. The GND film layer extends inward from the edge of the quartz surface to the inner ring close to the insulating layer.

2. The method for preparing a micro-hemispherical electrode according to claim 1, wherein: The specific process of step S1 is as follows: S1.1: Spray photoresist on the quartz surface and remove the photoresist except the bottom pattern on the quartz surface; S1.2: Plating a first metal film layer on the quartz surface, and then removing the bottom pattern to obtain a high-voltage film layer and a metal bottom film layer.

3. The method for preparing a micro-hemispherical electrode according to claim 2, wherein: The first metal film layer includes a first base film layer and a first functional film layer provided on the first base film layer. The first base film layer is made of Cr and / or Ti, and the first functional film layer is made of Au, Pt and / or Ag.

4. The method for preparing a micro-hemispherical electrode according to claim 3, wherein: The specific process of step S2 is as follows: S2.1: Spray photoresist on the quartz surface and remove the photoresist at the position corresponding to the quartz surface and the insulating film layer; S2.2: Coating an insulating film layer on the quartz surface and then removing the photoresist on the quartz surface.

5. The method for preparing a micro-hemispherical electrode according to claim 4, wherein: The insulating film layer is made of porous SiO2 or Si3N4.

6. The method for preparing a micro-hemispherical electrode according to claim 4, wherein: The specific process of step S3 is as follows: S3.1: Spraying photoresist on the quartz surface to remove the photoresist except for the top pattern on the quartz surface; the top pattern includes a middle circle, a plurality of frames, and the small circles; the middle circle extends outward from the center of the quartz surface to cover a portion of the insulating film layer; the plurality of frames are circumferentially spaced about the middle circle; S3.2: Plating a second metal film layer on the quartz surface, and then removing the top layer pattern to obtain multiple electrode film layers and a GND film layer.

7. The method for preparing a micro-hemispherical electrode according to claim 6, wherein: The second metal film layer includes a second base film layer and a second functional film layer provided on the second base film layer. The second base film layer is made of Cr and / or Ti, and the second functional film layer is made of Au, Pt and / or Ag.

8. The method for preparing a micro-hemispherical electrode according to claim 7, wherein: The thickness of the first base film layer is 50nm-200nm, the thickness of the first functional film layer is 500nm-2μm, the thickness of the insulating film layer is 1μm-2μm, the thickness of the second base film layer is 50nm-200nm, and the thickness of the second functional film layer is 500nm-2μm.

9. A micro-hemispherical electrode produced by the method according to any one of claims 1 to 8.

10. A micro-hemispherical resonant gyroscope, comprising a micro-hemispherical resonator, characterized in that: It also includes a micro-hemispherical electrode prepared by the preparation method according to any one of claims 1 to 8, wherein the central rod of the micro-hemispherical resonator is bonded to the high-voltage film layer at the center position of the surface of the micro-hemispherical electrode, and the lip edge of the micro-hemispherical resonator and the electrode film layer on the surface of the micro-hemispherical electrode constitute a detection or excitation capacitor.

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