Silicon resonance pressure sensor

Abstract

The invention provides a silicon resonance pressure sensor. The silicon resonance pressure sensor comprises a pressure sensing layer, a device layer and a substrate layer, the pressure sensing layer is arranged on one side of the device layer; a pressure film is arranged on the pressure sensing layer; the device layer is provided with a first resonator and a second resonator, and the first resonator and the second resonator are eccentrically arranged on two opposite sides of the device layer; the first resonator and the second resonator are respectively connected with a stress transfer block; the stress transfer block is connected with the pressure film; each of the first resonator and the second resonator comprises two groups of symmetrical resonance units, each group of resonance units comprises a main beam, a connecting beam, a first auxiliary beam and a second auxiliary beam, and the first auxiliary beam and the second auxiliary beam are connected with the main beam through the connecting beam. The silicon resonance pressure sensor has the technical effects that the influence of temperature on the resonance frequency of the silicon resonance pressure sensor can be reduced, the product stability and precision are greatly improved, and the service life is greatly prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of pressure sensors, and in particular relates to a silicon resonant pressure sensor. Background Art

[0002] Pressure sensors are generally divided into three types: piezoresistive, capacitive, and resonant. Currently, silicon resonant pressure sensors are widely used in important fields such as aviation and aerospace due to their high precision (the general accuracy of silicon resonant pressure sensors is within 0.02% FS, which is more than an order of magnitude better than piezoresistive pressure sensors), excellent stability, and good anti-interference performance (because they are mechanical vibration signals and the vibration frequency can be adjusted).

[0003] In addition to accuracy considerations, temperature drift is also a very important parameter of pressure sensors. However, current silicon resonant pressure resonance units are usually symmetrical structures, and their final performance is greatly affected by temperature, which greatly shortens their service life. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art and provide a new technical solution for a silicon resonant pressure sensor.

[0005] According to a first aspect of the present invention, there is provided a silicon resonant pressure sensor, comprising a pressure-sensing layer, a device layer and a substrate layer;

[0006] The pressure-sensitive layer is arranged on one side of the device layer; a pressure film is arranged on the pressure-sensitive layer;

[0007] The device layer is provided with a first resonator and a second resonator, and the first resonator and the second resonator are eccentrically arranged on opposite sides of the device layer; the first resonator and the second resonator are respectively connected with a stress transfer block; wherein the stress transfer block is connected to the pressure membrane, and the pressure membrane is used to sense external pressure and transfer the external pressure to the first resonator and the second resonator through the stress transfer block;

[0008] The first resonator and the second resonator each include two symmetrical groups of resonance units, each group of the resonance units includes a main beam, a connecting beam, a first sub-beam and a second sub-beam, the first sub-beam and the second sub-beam are respectively located at opposite sides of the main beam and are parallel to the main beam, and the first sub-beam and the second sub-beam are both connected to the main beam through the connecting beam; wherein the main beam, the connecting beam and the first sub-beam form an I-shaped structure, and the main beam, the connecting beam and the second sub-beam form an I-shaped structure;

[0009] The substrate layer is arranged on the other side of the device layer, and a groove corresponding to the resonance unit is arranged on the side of the substrate layer facing the device layer, and the groove is used to provide a deformation space for the vibration of the resonance unit.

[0010] Optionally, a plurality of square release holes are provided on the main beam, the first sub-beam and the second sub-beam.

[0011] Optionally, a plurality of triangular release holes are provided on the connecting beam.

[0012] Optionally, a first movable comb tooth is provided on a side of the first auxiliary beam away from the main beam, and the device layer is provided with a first fixed comb tooth corresponding to the first movable comb tooth; the first fixed comb tooth cooperates with the first movable comb tooth to form a first comb tooth pair;

[0013] A second movable comb tooth is arranged on a side of the second auxiliary beam away from the main beam, and the device layer is provided with a second fixed comb tooth corresponding to the second movable comb tooth; the second fixed comb tooth cooperates with the second movable comb tooth to form a second comb tooth pair;

[0014] A periodic driving signal is applied to the first comb teeth pair, so that the first sub-beam generates periodic vibration and drives the main beam and the second sub-beam to generate periodic vibration;

[0015] When external pressure is transmitted to the first resonator and the second resonator through the stress transmission block, the second comb teeth pair is used to detect the frequency change of the second sub-beam to detect the external pressure.

[0016] Optionally, one end of the main beam is connected to the stress transfer block, and the other end is grounded.

[0017] Optionally, the number of the grooves is two; each groove corresponds to two resonance units located on the same side.

[0018] Optionally, a ground pad, a capacitance detection pad and an electrostatic driving pad are provided on a side of the substrate layer away from the device layer;

[0019] The ground pad is connected to the ground area of ​​the device layer; the electrostatic drive pad is connected to the first fixed comb teeth; and the capacitance detection pad is connected to the second fixed comb teeth.

[0020] Optionally, the number of the ground pad, the capacitance detection pad and the electrostatic drive pad are all two.

[0021] Optionally, a plurality of connecting beams are connected between the main beam and the first sub-beam, and the plurality of connecting beams are parallel to each other;

[0022] A plurality of connecting beams are connected between the main beam and the second sub-beam, and the plurality of connecting beams are parallel to each other.

[0023] Optionally, the pressure membrane is square in shape.

[0024] A technical effect of the present invention is:

[0025] In the embodiment of the present application, the resonant structure of the silicon resonant pressure sensor forms a differential structure of vibration of the first resonator and the second resonator when the pressure membrane transmits external pressure to the two stress transfer blocks due to the differential setting of the two stress transfer blocks during mechanical vibration, thereby offsetting the influence of temperature on the resonant frequency and greatly improving the service life of the silicon resonant pressure sensor.

[0026] Furthermore, the main beam, the connecting beam, and the first sub-beam form an I-shaped structure, and the main beam, the connecting beam, and the second sub-beam form an I-shaped structure. The silicon resonant pressure sensor has multiple I-shaped structures, which significantly improves the stability of the resonant beam (that is, the main beam, the first sub-beam, and the second sub-beam) under vibration, which is beneficial to the stable output of the performance of the silicon resonant pressure sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic structural diagram of a silicon resonant pressure sensor according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic structural diagram of a device layer of a silicon resonant pressure sensor according to an embodiment of the present invention;

[0029] Figure 3 This is a schematic structural diagram of a first resonator or a second resonator of a silicon resonant pressure sensor according to an embodiment of the present invention;

[0030] Figure 4 This is a schematic structural diagram of a resonant unit of a silicon resonant pressure sensor according to an embodiment of the present invention;

[0031] Figure 5 This is a schematic structural diagram of a pressure membrane of a silicon resonant pressure sensor according to an embodiment of the present invention;

[0032] Figure 6 A schematic diagram of the structure of a groove in a substrate layer of a silicon resonant pressure sensor according to an embodiment of the present invention;

[0033] Figure 7 A mechanical simulation diagram of a silicon resonant pressure sensor from a first viewing angle according to an embodiment of the present invention;

[0034] Figure 8 A mechanical simulation diagram of a silicon resonant pressure sensor from a first viewing angle according to an embodiment of the present invention;

[0035] Fig. 9 This is a mechanical simulation diagram of a silicon resonant pressure sensor from a first perspective according to an embodiment of the present invention.

[0036] In the figure: 1. device layer; 101. grounding area; 102. electrostatic area; 103. detection area; 2. substrate layer; 21. groove; 31. first resonator; 32. second resonator; 4. resonance unit; 5. stress transfer block; 61. first movable comb teeth; 62. first fixed comb teeth; 63. second movable comb teeth; 64. second fixed comb teeth; 71. main beam; 72. connecting beam; 73. first sub-beam; 74. second sub-beam; 81. square release hole; 82. triangular release hole; 91. grounding pad; 92. capacitance detection pad; 93. electrostatic drive pad; 10. pressure sensing layer; 11. pressure membrane. DETAILED DESCRIPTION

[0037] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0038] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0039] The term "first" or "second" in the specification and claims of this application may include one or more of the features explicitly or implicitly. In the description of this application, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.

[0040] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0041] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] According to a first aspect of the present invention, see Figures 1 to 6 , a silicon resonant pressure sensor is provided, comprising a pressure-sensing layer 10, a device layer 1 and a substrate layer 2;

[0043] The pressure-sensitive layer 10 is disposed on one side of the device layer 1 ; a pressure film 10 is disposed on the pressure-sensitive layer 10 ;

[0044] The device layer 1 is provided with a first resonator 31 and a second resonator 32, and the first resonator 31 and the second resonator 32 are eccentrically arranged on opposite sides of the device layer 1; the first resonator 31 and the second resonator 32 are respectively connected with a stress transfer block 5 (the two stress transfer blocks 5 are also eccentrically arranged relative to the device layer); wherein the stress transfer block 5 is connected to the pressure membrane 10, and the pressure membrane 10 is used to sense external pressure and transfer the external pressure to the first resonator 31 and the second resonator 32 through the stress transfer block 5;

[0045] The first resonator 31 and the second resonator 32 each include two symmetrical groups of resonance units 4, each group of the resonance units 4 includes a main beam 71, a connecting beam 72, a first sub-beam 73 and a second sub-beam 74, the first sub-beam 73 and the second sub-beam 74 are respectively located at opposite sides of the main beam 71 and are parallel to the main beam 71, the first sub-beam 73 and the second sub-beam 74 are both connected to the main beam 71 through the connecting beam 72; wherein the main beam 71, the connecting beam 72, and the first sub-beam 73 form an I-shaped structure, and the main beam 71, the connecting beam 72, and the second sub-beam 74 form an I-shaped structure;

[0046] The substrate layer 2 is disposed on the other side of the device layer 1 , and a groove 21 corresponding to the resonance unit 4 is disposed on the side of the substrate layer 2 facing the device layer 1 , and the groove 21 is used to provide a deformation space for the vibration of the resonance unit 4 .

[0047] In the embodiment of the present application, the resonant structure of the silicon resonant pressure sensor forms a differential structure of vibration of the first resonator 31 and the second resonator 32 during mechanical vibration due to the asymmetric setting of the two stress transfer blocks 5, when the pressure membrane 10 transfers external pressure to the two stress transfer blocks 5, thereby offsetting the influence of temperature on the resonant frequency and greatly improving the service life of the silicon resonant pressure sensor.

[0048] Furthermore, the main beam 71, the connecting beam 72, and the first sub-beam 73 form an I-shaped structure, and the main beam 71, the connecting beam 72, and the second sub-beam 74 form an I-shaped structure. The silicon resonant pressure sensor has multiple I-shaped structures, which significantly improves the stability of the resonant beam (that is, the main beam 71, the first sub-beam 73, and the second sub-beam 74) under vibration, which is beneficial to the stable output of the performance of the silicon resonant pressure sensor.

[0049] Optionally, the main beam 71, the first sub-beam 73 and the second sub-beam 74 are all provided with a plurality of square release holes 81. The plurality of square release holes 81 can well reduce the mass of the main beam 71, the first sub-beam 73 and the second sub-beam 74, thereby achieving the purpose of regulating the reference frequency of the resonance unit 4.

[0050] Optionally, a plurality of triangular release holes 82 are provided on the connecting beam 72. The plurality of triangular release holes 82 can effectively reduce the mass of the connecting beam 72, thereby achieving the purpose of adjusting the reference frequency of the resonance unit 4.

[0051] Optionally, a first movable comb tooth 61 is provided on a side of the first auxiliary beam 73 away from the main beam 71, and the device layer 1 is provided with a first fixed comb tooth 62 corresponding to the first movable comb tooth 61; the first fixed comb tooth 62 cooperates with the first movable comb tooth 61 to form a first comb tooth pair;

[0052] A second movable comb tooth 63 is provided on a side of the second auxiliary beam 74 away from the main beam 71, and the device layer 1 is provided with a second fixed comb tooth 64 corresponding to the second movable comb tooth 63; the second fixed comb tooth 64 cooperates with the second movable comb tooth 63 to form a second comb tooth pair;

[0053] A periodic driving signal is applied to the first comb teeth pair, so that the first sub-beam 73 generates periodic vibration and drives the main beam 71 and the second sub-beam 74 to generate periodic vibration;

[0054] When external pressure is transmitted to the first resonator 31 and the second resonator 32 through the stress transmission block 5, the second comb teeth pair is used to detect the frequency change of the second sub-beam 74 (ie, the main beam 71 and the first sub-beam 73) to detect the external pressure.

[0055] In the above embodiment, the first comb teeth pair can realize periodic vibration of the first sub-beam 73, thereby driving the main beam 71 and the second sub-beam 74 to realize stable periodic vibration; the second comb teeth pair can measure the frequency change of the resonance unit 4, thereby realizing the measurement of the external pressure.

[0056] The structural design of the resonance unit 4 in the present application is relatively reasonable, which helps to improve the accuracy and precision of pressure detection.

[0057] Optionally, one end of the main beam 71 is connected to the stress transfer block 5, and the other end is grounded, which better ensures the stability of the grounding of the silicon resonant pressure sensor, thereby ensuring that the silicon resonant pressure sensor has better working performance.

[0058] Exemplarily, the device layer 1 has a grounding area 101, an electrostatic area 102 and a detection area 103, the other end of the main beam is connected to the grounding area 101, and the connection length between the first main beam of the first resonator and the grounding area 101 is different from the connection length between the first main beam of the second resonator and the grounding area 101, thereby forming an eccentric setting of the first resonator 31 and the second resonator 32 relative to the device layer 1.

[0059] For example, the first resonator 31 and the second resonator 32 each correspond to a detection area 103 , the detection area 103 is located between the two resonance units, and the second fixed comb teeth are arranged in the detection area 103 .

[0060] Exemplarily, the device layer 1 is rectangular, and the device layer has a first side wall, a second side wall, a third side wall and a fourth side wall connected in sequence, the first side wall is opposite to the third side wall, the second side wall is opposite to the fourth side wall, the two grounding regions 101 are respectively close to the first side wall and the third side wall, and the two electrostatic regions 102 are respectively close to the second side wall and the fourth side wall. The two electrostatic regions 102 are respectively located on opposite sides of the first resonator or the second resonator. Each electrostatic region 102 is connected to two first fixed comb teeth 62 located on the same side.

[0061] Optionally, there are two grooves 21, and each groove 21 corresponds to two resonance units 4 on the same side. The design of the grooves 21 is relatively reasonable, and can provide deformation space for the vibration of the resonance unit 4, thereby ensuring the effectiveness of the vibration of the resonance unit 4 and thus ensuring the measurement accuracy of the silicon resonant pressure sensor.

[0062] Optionally, a ground pad 91, a capacitance detection pad 92 and an electrostatic driving pad 93 are provided on a side of the substrate layer 2 away from the device layer 1;

[0063] The ground pad 91 is connected to the ground area 101 of the device layer 1; the electrostatic drive pad 93 is connected to the first fixed comb teeth 62, that is, the electrostatic drive pad 93 is connected to the electrostatic area 102; the capacitance detection pad 92 is connected to the second fixed comb teeth 64, that is, the capacitance detection pad 92 is connected to the detection area 103.

[0064] In the above embodiment, the ground pad 91, the capacitance detection pad 92 and the electrostatic driving pad 93 are reasonably designed, which helps to ensure the stability of the electrical connection of each component.

[0065] Optionally, the number of the ground pad 91, the capacitance detection pad 92 and the electrostatic drive pad 93 are all two. This better optimizes the connection circuit of the silicon resonant pressure sensor.

[0066] Optionally, a plurality of connecting beams 72 are connected between the main beam 71 and the first sub-beam 73, and the plurality of connecting beams 72 are parallel to each other;

[0067] A plurality of connecting beams 72 are connected between the main beam 71 and the second sub-beam 74 , and the plurality of connecting beams 72 are parallel to each other.

[0068] In the above implementation, it helps to ensure the consistency and stability of the vibration of the resonance unit 4 and helps to improve the measurement accuracy of the silicon resonant pressure sensor.

[0069] Optionally, the pressure membrane 10 is in a square shape, which helps to accurately input the external pressure into the silicon resonant pressure sensor through the pressure membrane 10 .

[0070] It should be noted that see Figures 7 to 9 According to the mechanical simulation diagram of the silicon resonant pressure sensor, by eccentrically setting the two stress transfer blocks at different positions, when the pressure film of the pressure-sensing layer is deformed under force, the stress will directly act on the two stress transfer blocks, thereby driving the resonant unit of the first resonator and the resonant unit of the second resonator to deform in different directions ε. The silicon resonant pressure sensor forms a differential structure of the resonant unit of the first resonator and the resonant unit of the second resonator, which greatly offsets the influence of temperature on the device.

[0071] In the embodiment of the present application, the external pressure is transmitted to the first resonator 31 and the second resonator 32 through the pressure membrane 10 deforming and squeezing the stress transfer block 5. The first resonator 31 and the second resonator 32 can form a differential structure, thereby offsetting the influence of the temperature on the overall performance drift of the silicon resonant pressure sensor and avoiding the excessive influence of the temperature drift caused by a single resonator.

[0072] Therefore, the present application reduces the resonance frequency drift caused by temperature change and stress by setting the output of the differential structure frequency of the first resonator and the second resonator, thereby improving the stability, accuracy, service life, etc. of the sensor.

[0073] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A silicon resonant pressure sensor, characterized in that: including a pressure-sensitive layer, a device layer and a substrate layer; The pressure-sensitive layer is arranged on one side of the device layer; a pressure film is arranged on the pressure-sensitive layer; The device layer is provided with a first resonator and a second resonator, and the first resonator and the second resonator are eccentrically arranged on opposite sides of the device layer; the first resonator and the second resonator are respectively connected with a stress transfer block; wherein the stress transfer block is connected to the pressure membrane, and the pressure membrane is used to sense external pressure and transfer the external pressure to the first resonator and the second resonator through the stress transfer block; The first resonator and the second resonator each include two symmetrical groups of resonance units, each group of the resonance units includes a main beam, a connecting beam, a first sub-beam and a second sub-beam, the first sub-beam and the second sub-beam are respectively located at opposite sides of the main beam and are parallel to the main beam, and the first sub-beam and the second sub-beam are both connected to the main beam through the connecting beam; wherein the main beam, the connecting beam and the first sub-beam form an I-shaped structure, and the main beam, the connecting beam and the second sub-beam form an I-shaped structure; The substrate layer is arranged on the other side of the device layer, and a groove corresponding to the resonance unit is arranged on the side of the substrate layer facing the device layer, and the groove is used to provide a deformation space for the vibration of the resonance unit.

2. The silicon resonant pressure sensor according to claim 1, characterized in that: A plurality of square release holes are arranged on the main beam, the first sub-beam and the second sub-beam.

3. The silicon resonant pressure sensor according to claim 2, characterized in that: A plurality of triangular release holes are arranged on the connecting beam.

4. The silicon resonant pressure sensor according to claim 1, characterized in that: A first movable comb tooth is disposed on a side of the first auxiliary beam away from the main beam, and the device layer is provided with a first fixed comb tooth corresponding to the first movable comb tooth; the first fixed comb tooth cooperates with the first movable comb tooth to form a first comb tooth pair; A second movable comb tooth is arranged on a side of the second auxiliary beam away from the main beam, and the device layer is provided with a second fixed comb tooth corresponding to the second movable comb tooth; the second fixed comb tooth cooperates with the second movable comb tooth to form a second comb tooth pair; A periodic driving signal is applied to the first comb teeth pair, so that the first sub-beam generates periodic vibration and drives the main beam and the second sub-beam to generate periodic vibration; When external pressure is transmitted to the first resonator and the second resonator through the stress transmission block, the second comb teeth pair is used to detect the frequency change of the second sub-beam to detect the external pressure.

5. The silicon resonant pressure sensor according to claim 4, characterized in that: One end of the main beam is connected to the stress transfer block, and the other end is grounded.

6. The silicon resonant pressure sensor according to claim 5, characterized in that: The number of the grooves is two; each groove corresponds to two resonance units located on the same side.

7. The silicon resonant pressure sensor according to claim 6, characterized in that: A ground pad, a capacitance detection pad and an electrostatic drive pad are arranged on one side of the substrate layer away from the device layer; The ground pad is connected to the ground area of ​​the device layer; the electrostatic drive pad is connected to the first fixed comb teeth; and the capacitance detection pad is connected to the second fixed comb teeth.

8. The silicon resonant pressure sensor according to claim 7, characterized in that: The number of the ground pad, the capacitance detection pad and the electrostatic driving pad are all two.

9. The silicon resonant pressure sensor according to claim 7, characterized in that: A plurality of connecting beams are connected between the main beam and the first sub-beam, and the plurality of connecting beams are parallel to each other; A plurality of connecting beams are connected between the main beam and the second sub-beam, and the plurality of connecting beams are parallel to each other.

10. The silicon resonant pressure sensor according to claim 1, characterized in that: The pressure membrane is in a square shape.

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