Resonant differential pressure sensor and manufacturing method thereof

Abstract

The invention provides a resonant differential pressure sensor and a manufacturing method thereof, the resonant differential pressure sensor comprises a substrate layer and a pressure sensing layer arranged on the substrate layer, and the pressure sensing layer is provided with a pressure sensing area cavity and a resonant area cavity; the vibration beam layer is arranged on the pressure sensing layer and covers the pressure sensing area cavity and the resonance area cavity, a first air guide hole and a vibration beam are arranged on the vibration beam layer, the first air guide hole is communicated with the pressure sensing area cavity, and a hollow area is arranged on the vibration beam; the sealing cap layer is arranged on the vibration beam layer, a second air guide hole and a first concave cavity are formed in the sealing cap layer, the second air guide hole is communicated with the first air guide hole, and the first concave cavity and the resonance area concave cavity are communicated through the hollow area and surround the vibration beam in the closed cavity. The vibration beam is surrounded in the closed cavity through the first concave cavity and the resonance area concave cavity, enough space is provided for the vibration beam, the first air guide hole and the second air guide hole are communicated with the pressure sensing area concave cavity, it is ensured that a pressure signal is efficiently transmitted from the pressure sensing layer to the vibration beam layer without leakage, and product stress is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, and in particular to a resonant differential pressure sensor and its manufacturing method. Background Technology

[0002] With the rapid development of semiconductor technology, sensors, as key components for information acquisition, are increasingly widely used in industries such as manufacturing, medicine, and energy. Among them, resonant differential pressure sensors have become an important technical means for high-precision pressure measurement due to their high precision, high stability, and strong anti-interference capabilities.

[0003] Currently, the main technical solution for resonant differential pressure sensors is silicon micromachining technology. Pressure measurement is achieved through the design and manufacture of silicon resonant pressure sensors. Specific methods include wafer-level bonding processes such as silicon-glass bonding or silicon-silicon bonding. Combined with MEMS microsensor technology, high-sensitivity resonant differential pressure sensors are fabricated. Based on mechanical resonance technology, pressure changes are converted into changes in resonant frequency, thereby realizing quasi-digital signal output, which is convenient for interfacing with microprocessors.

[0004] However, in the aforementioned resonant differential pressure sensor technologies, the silicon-glass bonding process involves significant encapsulation stress, which can easily lead to temperature drift. Furthermore, the silicon-silicon bonding process is more complex and has a lower yield. Additionally, since the quartz resonator (resonating beam) must be housed in a sealed, low-pressure cavity unaffected by external pressure, the use of gold wire bonding to lead out wires and chip-level micro-assembly is technically challenging and inefficient. The gold wires are anchored to the pressure-sensing diaphragm through the resonating beam structure layer, and the thermal deformation of the gold wires themselves can affect the pressure-sensing diaphragm, causing frequency drift in the resonating beam. Moreover, the pressure-sensing diaphragm typically uses a flat structure, making it difficult to effectively remove residual stress, resulting in zero-point drift and decreased accuracy of the sensor. Summary of the Invention

[0005] This invention provides a resonant differential pressure sensor and its manufacturing method, which solves the defect in the prior art where residual stress cannot be effectively removed, leading to a decrease in sensor accuracy. It can effectively reduce product stress and improve stability.

[0006] This invention provides a resonant differential pressure sensor, comprising: a substrate layer; a pressure-sensing layer disposed on the substrate layer, the pressure-sensing layer having a pressure-sensing cavity and a resonant cavity; a vibrating beam layer disposed on the pressure-sensing layer and covering the pressure-sensing cavity and the resonant cavity, the vibrating beam layer having a first vent hole and a vibrating beam, the first vent hole being connected to the pressure-sensing cavity, the vibrating beam having a hollowed-out area; and a capping layer disposed on the vibrating beam layer, the capping layer having a second vent hole and a first cavity, the second vent hole being connected to the first vent hole, the first cavity and the resonant cavity being connected through the hollowed-out area to form a sealed chamber, thereby surrounding the vibrating beam within the sealed chamber.

[0007] According to the present invention, a resonant differential pressure sensor has at least two pressure-sensing cavities, which are symmetrically distributed on the pressure-sensing layer. The resonant cavities are arranged in a one-to-one correspondence with the vibrating beam. The resonant cavities are located between the symmetrically distributed pressure-sensing cavities. The pressure-sensing layer also includes bosses, which are arranged between adjacent resonant cavities.

[0008] According to the present invention, the thickness of the pressure-sensing layer ranges from 108 μm to 500 μm, and the measuring range ranges from 100 kPa to 50.1 MPa; and / or, the height of the boss ranges from 10 μm to 60 μm; and / or, the height of the boss is equal to the depth of the cavity in the resonant region.

[0009] According to the present invention, a resonant differential pressure sensor is provided in which a first air guide hole is provided in a one-to-one correspondence with a pressure sensing cavity; the number of vibrating beams is at least one, and the vibrating beams are parallel to the crystal Y-axis of the vibrating beam layer, wherein the crystal Y-axis represents a mechanical axis perpendicular to the crystal facet of the vibrating beam layer.

[0010] According to the present invention, a resonant differential pressure sensor has three vibrating beams, including a first edge vibrating beam, a central vibrating beam, and a second edge vibrating beam. The first edge vibrating beam, the central vibrating beam, and the second edge vibrating beam are arranged on the same straight line and parallel to the Y-axis of the crystal. An anchor area is provided between the ends of adjacent vibrating beams. The anchor area is set on a boss and rigidly connected to the boss. The first edge vibrating beam is used for the wiring of the central vibrating beam. The central vibrating beam and the second edge vibrating beam are used for measuring pressure.

[0011] According to the resonant differential pressure sensor provided by the present invention, when the Y-axis direction of the crystal is parallel to the diagonal direction of the vibrating beam layer, the vibrating beams are arranged on the same straight line along the diagonal direction of the vibrating beam layer; or, when the Y-axis direction of the crystal is parallel to the edge direction of the vibrating beam layer, the vibrating beams are arranged on the same straight line along the edge direction of the vibrating beam layer.

[0012] According to the present invention, a resonant differential pressure sensor is provided on the substrate layer, wherein a second cavity and a third air guide hole are provided, the second cavity is located on the side of the substrate layer adjacent to the pressure-sensing layer and the pressure-sensing layer covers the second cavity, and the third air guide hole penetrates the substrate layer and is connected to the second cavity.

[0013] This invention also provides a method for manufacturing a resonant differential pressure sensor, comprising: forming a substrate layer, a pressure-sensing layer, a resonant beam layer, and a capping layer respectively; forming a pressure-sensing region cavity and a resonant region cavity on the pressure-sensing layer; forming a first vent hole and a resonant beam on the resonant beam layer; forming a second vent hole and a first cavity on the capping layer; and forming a hollow area on the resonant beam; performing wafer-level bonding on the capping layer, the resonant beam layer, and the pressure-sensing layer using a bonding process to obtain a bonding assembly; wherein the first cavity and the resonant region cavity are connected through the hollow area to form a sealed chamber, thereby surrounding the resonant beam within the sealed chamber; the first vent hole and the second vent hole are connected to the pressure-sensing region cavity; and performing secondary wafer-level bonding on the bonding assembly and the substrate layer using a bonding process.

[0014] According to a method for manufacturing a resonant differential pressure sensor provided by the present invention, the bonding process includes a metal bonding process. The bonding process is used to perform wafer-level bonding of a capping layer, a resonant beam layer, and a pressure-sensing layer, including: forming metal sealing rings on the capping layer and the resonant beam layer respectively using a magnetron sputtering process, and forming metal sealing rings on the first surfaces of the resonant beam layer and the pressure-sensing layer respectively; and bonding the metal sealing rings on the capping layer and the resonant beam layer, as well as the metal sealing rings on the resonant beam layer and the pressure-sensing layer, using the metal bonding process. Using metal bonding technology, secondary wafer-level bonding is performed on the bonding assembly and the substrate layer, including: for the bonding assembly and pressure-sensitive layer to be bonded, using magnetron sputtering technology, metal sealing rings are formed on the second side of the pressure-sensitive layer of the bonding assembly opposite to the first side and on the substrate layer, respectively, and then using metal bonding technology, the metal sealing rings on the pressure-sensitive layer and the substrate layer are bonded.

[0015] According to the present invention, a method for manufacturing a resonant differential pressure sensor includes a quartz bonding process. The bonding process is used to perform wafer-level bonding of the capping layer, the resonant beam layer, and the pressure-sensing layer. The method includes: directly bonding the capping layer, the resonant beam layer, and the pressure-sensing layer using the quartz bonding process to obtain a bonding assembly. Using bonding processes, secondary wafer-level bonding is performed on the bonding assembly and the substrate layer, including: using quartz bonding processes to directly bond the pressure-sensitive layer and the substrate layer in the bonding assembly.

[0016] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a method for manufacturing a resonant differential pressure sensor as described above.

[0017] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a method for manufacturing a resonant differential pressure sensor as described above.

[0018] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements a method for manufacturing a resonant differential pressure sensor as described above.

[0019] The resonant differential pressure sensor and its manufacturing method provided by this invention utilize a base layer as the fundamental support layer for the sensor, providing a flat and robust foundation for the pressure-sensing layer and the vibrating beam layer. This reduces the impact of external vibrations or temperature changes on the internal structure of the sensor, improving measurement stability. Furthermore, the pressure-sensing cavity and the resonant cavity structure of the pressure-sensing layer enable independent optimization of pressure detection and resonance functions, avoiding mutual interference. The vibrating beam layer covers the pressure-sensing cavity and the resonant cavity, communicating with the pressure-sensing layer through a first air vent to ensure zero-delay pressure transmission between the pressure-sensing layer and the vibrating beam layer, improving dynamic response speed. The first cavity of the sealing layer further enhances this effect. The resonant cavity of the pressure-sensing layer, along with the hollowed-out area of ​​the vibrating beam, surrounds the vibrating beam within a sealed chamber, effectively protecting the vibrating beam area of ​​the vibrating beam layer. This provides sufficient space for the oscillation of the vibrating beam, ensuring that the quartz resonator has a high quality factor and improving the sensor's shock resistance. Furthermore, the second vent connects to the first vent, ensuring efficient and leak-free transmission of the pressure signal from the pressure-sensing layer to the vibrating beam layer. Through multi-layer integration, efficient conversion between pressure and frequency can be achieved, effectively reducing product stress and improving stability. Moreover, the multi-layer stacking design significantly reduces the sensor's volume, facilitating its application in space-constrained scenarios and achieving the advantages of high precision, high stability, and miniaturization. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the resonant differential pressure sensor provided by the present invention; Figure 2 This is a schematic diagram of the base layer structure provided by the present invention; Figure 3 This is a schematic diagram of the pressure-sensitive layer provided by the present invention; Figure 4 This is a schematic diagram of the structure of the vibrating beam layer provided by the present invention; Figure 5 This is a schematic diagram of the capping layer provided by the present invention; Figure 6 This is a schematic flowchart of the manufacturing method of the resonant differential pressure sensor provided by the present invention; Figure 7This is a schematic diagram of the structure of the electronic device provided by the present invention.

[0022] Figure label: 1: Base layer; 11: Second cavity; 12: Third vent; 2: Pressure-sensing layer; 21: Pressure-sensing area cavity; 22: Resonance area cavity; 23: Boss; 3: Vibrating beam layer; 31: First vent; 32: Vibrating beam; 321: First edge vibrating beam; 322: Central vibrating beam; 323: Second edge vibrating beam; 33: Hollowed-out area; 34: Anchor area; 4: Capping layer; 41: Second vent; 42: First cavity; 43: Electrode lead-out hole. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] Figure 1 This is a schematic diagram of the resonant differential pressure sensor provided by the present invention, as shown below. Figure 1 As shown, the resonant differential pressure sensor includes: Basal layer 1; The pressure-sensitive layer 2 is disposed on the base layer 1, and the pressure-sensitive layer 2 is provided with a pressure-sensitive cavity 21 and a resonant cavity 22. The vibrating beam layer 3 is disposed on the pressure-sensing layer 2 and covers the pressure-sensing area cavity 21 and the resonant area cavity 22. The vibrating beam layer 3 is provided with a first air guide hole 31 and a vibrating beam 32. The first air guide hole 31 is connected to the pressure-sensing area cavity 21. The vibrating beam is provided with a hollow area 33. A capping layer 4 is disposed on the vibrating beam layer 3. The capping layer 4 is provided with a second air guide hole 41 and a first cavity 42. The second air guide hole 41 is connected to the first air guide hole 31. The first cavity 42 and the resonant area cavity 22 are connected through the hollow area 32 to form a sealed chamber, so as to surround the vibrating beam 32 in the sealed chamber.

[0025] In this embodiment, a second cavity 11 and a third air vent 12 are provided on the base layer. The second cavity 11 is located on the side of the base layer adjacent to the pressure-sensitive layer 2, and the pressure-sensitive layer 2 covers the second cavity 11. The third air vent 12 penetrates the base layer 1 and is connected to the second cavity 21.

[0026] It should be added that by covering the second concave cavity with the pressure-sensitive layer, a cavity is formed on the other side of the pressure-sensitive layer opposite to the concave cavity forming the pressure-sensitive area and the resonant area. This allows gas to enter the second concave cavity from the third air guide hole, thereby acting on the side of the pressure-sensitive layer to provide space for the deformation of the pressure-sensitive layer.

[0027] Furthermore, while the cross-sectional shape of the second cavity is rectangular, in other embodiments of the present invention, the cross-sectional shape of the second cavity can also be circular, elliptical, or a polygon other than a rectangle, such as a pentagon or hexagon. No further limitation is made here. The second cavity can be formed by etching the base layer using an etching process. Additionally, the top view shape of the second cavity can be set according to the actual deformation space required by the pressure-sensitive layer. For example, it can be a polygon or an irregular structure. Irregular structures include octagonal structures where any two opposite sides of the octagon are connected to a rectangular structure. The octagonal structure can be an equilateral octagon or an irregular octagon. No further limitation is made here. (See reference...) Figure 2 No further restrictions are imposed here.

[0028] In one alternative embodiment, reference Figure 3 The pressure-sensing cavity 21 has at least two symmetrically distributed on the pressure-sensing layer 2. The resonant cavity 22 is arranged in a one-to-one correspondence with the vibrating beam 32. The resonant cavity 22 is located between the symmetrically distributed pressure-sensing cavities 21. The pressure-sensing layer also includes a boss 23, which is arranged between adjacent resonant cavities.

[0029] It should be noted that the pressure-sensing layer detects pressure changes in the external fluid, converting these changes into stress or strain. The strain of the pressure-sensing layer is amplified by the bosses to improve its sensitivity. Furthermore, the presence of concave cavities in the pressure-sensing zone provides space for deformation, effectively reducing the impact of assembly stress, thermal stress, and vibration shock on the pressure-sensing membrane stress. This prevents distortion of the pressure-sensing membrane due to over-positioning or high / low temperature testing, thereby reducing zero drift. Additionally, the number and location distribution of the resonant zone cavities can be referenced in the description of the vibrating beam configuration of the vibrating beam layer below, and will not be further described here.

[0030] Furthermore, the cross-sectional shape of the pressure-sensing cavity is rectangular. However, in other embodiments of the present invention, the cross-sectional shape of the pressure-sensing cavity can also be circular, elliptical, or a polygon other than a rectangle, such as a pentagon or hexagon, etc., without further limitation. Additionally, the top view shape of the pressure-sensing cavity can be set according to the actual required deformation space of the pressure-sensing layer. For example, it can be a polygon or an irregular structure, such as the shape of a rectangle after cutting off two triangles on the same side, without further limitation. Furthermore, the pressure-sensing cavity can be formed by etching the pressure-sensing layer using an etching process, without further limitation.

[0031] Furthermore, the cross-sectional shape of the resonant cavity is rectangular. However, in other embodiments of the present invention, the cross-sectional shape of the resonant cavity can also be circular, elliptical, or a polygon other than a rectangle, such as a pentagon or hexagon, etc., without further limitation here. Additionally, the top view shape of the resonant cavity can be designed according to the actual required oscillation space of the vibrating beam layer, for example, it can be rectangular, etc., without further limitation here. Furthermore, the resonant cavity can be formed by etching the pressure-sensitive layer using an etching process.

[0032] In one optional embodiment, the thickness of the pressure-sensitive layer ranges from 108 μm to 500 μm, and the measurement range is from 100 kPa to 50.1 MPa; and / or, the height of the boss ranges from 10 μm to 60 μm; and / or, the height of the boss is equal to the depth of the resonant cavity.

[0033] In one alternative embodiment, reference Figure 4 The first vent hole 31 is provided in a one-to-one correspondence with the pressure-sensing cavity 21; the number of vibrating beams is at least one, and the vibrating beam 32 is parallel to the crystal Y-axis of the vibrating beam layer, where the crystal Y-axis represents the mechanical axis perpendicular to the crystal facet of the vibrating beam layer. It should be noted that the first vent holes are symmetrically distributed on both sides of the diagonal and can be formed by etching the vibrating beam layer through an etching process.

[0034] Specifically, there are three vibrating beams, including a first edge vibrating beam 321, a central vibrating beam 322, and a second edge vibrating beam 323. The first edge vibrating beam 321, the central vibrating beam 322, and the second edge vibrating beam 323 are arranged on the same straight line and parallel to the Y-axis of the crystal. An anchor area 34 is provided between the ends of adjacent vibrating beams. The anchor area 34 is set on the boss 23 and rigidly connected to the boss 23. The first edge vibrating beam 321 is used for the wiring of the central vibrating beam; the central vibrating beam 322 and the second edge vibrating beam 323 are used for measuring pressure.

[0035] It should be added that the central vibrating beam and the second edge vibrating beam convert the strain of the pressure-sensitive layer into frequency changes. By calculating the difference between the frequencies output by the two vibrating beams, the temperature common-mode error is suppressed and the linearity is improved. An electrical signal is then extracted through the first edge vibrating beam.

[0036] In one optional embodiment, when the crystal's Y-axis direction is parallel to the diagonal direction of the vibrating beam layer, the vibrating beams are arranged in a straight line along the diagonal direction of the vibrating beam layer; or, when the crystal's Y-axis direction is parallel to the edge direction of the vibrating beam layer, the vibrating beams are arranged in a straight line along the edge direction of the vibrating beam layer. It should be noted that arranging the vibrating beams along the diagonal is beneficial for reducing size. Alternatively, they can be arranged parallel to the edge direction of the vibrating beam layer, but it is necessary to ensure that the vibrating beam direction is parallel to the crystal's Y-axis of the vibrating beam layer.

[0037] In one alternative embodiment, reference Figure 5 The first air guide holes 31 are symmetrically distributed on both sides of the first concave cavity 42. The number of the first concave cavities 42 is matched according to the number of vibrating beams. For example, the vibrating beams include the first edge vibrating beam, the center vibrating beam, and the second edge vibrating beam. The first concave cavity 42 is three in total, and each vibrating beam is located within the projection range of the corresponding first concave cavity 42 in the vibrating beam layer.

[0038] In addition, the capping layer is also provided with electrode lead-out holes 43. The electrode lead-out holes 43 are respectively disposed at the ends of the linearly arranged first concave cavities 42 that are not adjacent to other first concave cavities 42, and are symmetrically distributed on both sides of the first concave cavities 42. The sidewalls of the electrode lead-out holes are covered with electrodes. By filling the electrode lead-out holes of the capping layer with metal material, metal eutectic will occur under high temperature conditions, thereby leading the electrical signal led out by the first edge vibrating beam to the outside.

[0039] Furthermore, the metallic material includes at least one of indium-sealed, tin-sealed, gold-indium eutectic, and gold-tin eutectic.

[0040] In addition, the capping layer is also provided with wiring grooves. The wiring grooves can be set according to the actual wiring requirements. For example, a wiring groove can be set between the first cavity of the first edge vibrating beam and the center vibrating beam. No further limitation is made here.

[0041] It should be noted that the diameter of the second air guide hole is less than or equal to the diameter of the first air guide hole, and the central axis of the second air guide hole is on the same straight line as the central axis of the first air guide hole. Furthermore, the distribution of the second air guide hole can be similar to that of the first air guide hole, and will not be repeated here.

[0042] In one optional embodiment, the base layer, pressure-sensitive layer, vibrating beam layer, and capping layer are made of quartz crystal material to reduce the stress caused by the mismatch of the material's thermal expansion coefficients, improve the matching of the material's thermal expansion coefficients, and thus avoid temperature drift caused by the mismatch of the material's thermal expansion coefficients.

[0043] In summary, this embodiment of the invention uses a base layer as the fundamental support layer for the sensor, providing a flat and robust base for the pressure-sensing layer and the vibrating beam layer. This reduces the impact of external vibrations or temperature changes on the internal structure of the sensor, improving measurement stability. Furthermore, the pressure-sensing cavity and resonant cavity structure of the pressure-sensing layer enable independent optimization of pressure detection and resonance functions, avoiding mutual interference. The vibrating beam layer covers the pressure-sensing cavity and resonant cavity, communicating with the pressure-sensing layer through a first air vent, ensuring no delay in pressure transmission between the pressure-sensing layer and the vibrating beam layer, thus improving dynamic response speed. Finally, the first cavity of the capping layer and the pressure-sensing layer... The hollowed-out area of ​​the resonant cavity and the vibrating beam surround the vibrating beam in a sealed chamber, effectively protecting the vibrating beam area of ​​the vibrating beam layer and providing sufficient space for the oscillation of the vibrating beam. This ensures that the quartz resonator has a high quality factor, improves the sensor's shock resistance, and connects to the first vent through the second vent, ensuring efficient and leak-free transmission of pressure signals from the pressure-sensing layer to the vibrating beam layer. Through multi-layer integration, it can achieve efficient conversion between pressure and frequency, effectively reducing product stress and improving stability. Moreover, the multi-layer stacking design significantly reduces the sensor size, making it suitable for applications in space-constrained scenarios, and achieving the advantages of high precision, high stability, and miniaturization.

[0044] The manufacturing method of the resonant differential pressure sensor provided by the present invention will be described below. The manufacturing method of the resonant differential pressure sensor described below can be referred to in correspondence with the resonant differential pressure sensor described above.

[0045] Figure 6 A schematic flowchart of a method for manufacturing a resonant differential pressure sensor is shown. The method includes: S61, respectively forming a base layer, a pressure-sensitive layer, a vibrating beam layer and a capping layer, a pressure-sensitive area cavity and a resonant area cavity are formed on the pressure-sensitive layer, a first air guide hole and a vibrating beam are formed on the vibrating beam layer, a second air guide hole and a first cavity are formed on the capping layer, and a hollow area is formed on the vibrating beam. S62, using bonding technology, wafer-level bonding is performed on the capping layer, the resonant beam layer and the pressure-sensing layer to obtain a bonding combination; wherein, the first cavity and the resonant region cavity are connected through the hollow area to form a sealed chamber, so as to surround the resonant beam in the sealed chamber, and the first vent hole and the second vent hole are connected to the pressure-sensing region cavity. S63 utilizes a bonding process to perform secondary wafer-level bonding between the bonding assembly and the substrate layer.

[0046] It should be noted that the step numbers "S61-S63" in this specification do not represent the order of the manufacturing method of the resonant differential pressure sensor. The manufacturing method of the resonant differential pressure sensor of the present invention is described in detail below.

[0047] In step S61, a base layer, a pressure-sensitive layer, a vibrating beam layer, and a capping layer are formed respectively. A pressure-sensitive cavity and a resonant cavity are formed on the pressure-sensitive layer. A first air guide hole and a vibrating beam are formed on the vibrating beam layer. A second air guide hole and a first cavity are formed on the capping layer. A hollow area is formed on the vibrating beam.

[0048] It should be noted that the base layer, pressure-sensitive layer, vibrating beam layer, and capping layer can be made of quartz crystal material, and can be formed using QMEMS processes, including cleaning, coating, photolithography, and wet etching. For example, the base layer can be formed by providing a quartz crystal base layer and etching it to form a third vent hole penetrating the base layer and a second cavity. Furthermore, the formation process of the pressure-sensitive layer, vibrating beam layer, and capping layer can be similar to that of the base layer, and will not be further elaborated here.

[0049] Step S62: Using a bonding process, the capping layer, the resonant beam layer, and the pressure-sensing layer are bonded at the wafer level to obtain a bonding combination; wherein, the first cavity and the resonant region cavity are connected through a hollow area to form a sealed chamber, so as to surround the resonant beam in the sealed chamber, and the first vent hole and the second vent hole are connected to the pressure-sensing region cavity.

[0050] In this embodiment, since the base layer, pressure-sensitive layer, vibrating beam layer and capping layer are made of quartz crystal material, they can be bonded together using a bonding process.

[0051] In one optional embodiment, the bonding process includes a quartz bonding process, which is used to perform wafer-level bonding of the capping layer, the resonant beam layer, and the pressure-sensitive layer, including: directly bonding the capping layer, the resonant beam layer, and the pressure-sensitive layer using the quartz bonding process to obtain a bonding assembly.

[0052] In another optional embodiment, the bonding process includes a metal bonding process, which performs wafer-level bonding of the capping layer, the resonant beam layer, and the pressure-sensing layer. This includes: forming metal sealing rings on the capping layer and the resonant beam layer using magnetron sputtering, and forming metal sealing rings on the first surfaces of the resonant beam layer and the pressure-sensing layer; and bonding the metal sealing rings on the capping layer and the resonant beam layer, as well as the metal sealing rings on the resonant beam layer and the pressure-sensing layer, using the metal bonding process. It should be noted that in other embodiments, the bonding between the capping layer and the resonant beam layer, and between the resonant beam layer and the pressure-sensing layer, can also be performed sequentially; this is not further limited here.

[0053] Furthermore, using magnetron sputtering, metal sealing rings are formed on the capping layer and the vibrating beam layer respectively, and metal bonding is used to bond the metal sealing rings on the capping layer and the vibrating beam layer. This includes: using magnetron sputtering, forming a first metal film on the capping layer and the vibrating beam layer respectively, as an adhesion layer in contact with the corresponding capping layer and vibrating beam layer; and using magnetron sputtering, forming a second metal film on the capping layer and the vibrating beam layer respectively, as an electrode layer.

[0054] When the capping layer and the vibrating beam layer are bonded at the wafer level, the metal sealing rings of the capping layer and the vibrating beam layer form a eutectic through a first metal film, a second metal film-second metal film, and a first metal film hot-pressing, thereby sealing the capping layer and the vibrating beam layer. Furthermore, the second metal film can be made of gold, and the first metal film can be made of at least one of chromium, tin, germanium, or indium.

[0055] In one alternative embodiment, the material of the first metal film is chromium.

[0056] In one alternative embodiment, the metal sealing rings on the cap layer and the vibrating beam layer may have the same or different shapes. It should be noted that the cross-sectional area of ​​any metal sealing ring on the cap layer and the vibrating beam layer is greater than or equal to the cross-sectional area of ​​the other metal sealing ring.

[0057] Furthermore, the wafer-level bonding of the vibrating beam layer and the pressure-sensitive layer can refer to the wafer-level bonding principle of the capping layer and the vibrating beam layer, which will not be repeated here.

[0058] Step S63: Using metal bonding technology, perform secondary wafer-level bonding on the bonding assembly and the substrate layer.

[0059] Similarly, since the base layer, pressure-sensitive layer, vibrating beam layer and capping layer are made of quartz crystal material, the bonded combination obtained by bonding can be bonded to the base layer through bonding process, resulting in lower product stress and better stability.

[0060] In one optional embodiment, the bonding process includes a quartz bonding process, which is used to perform secondary wafer-level bonding of the bonding assembly and the substrate layer, including: using the quartz bonding process to directly bond the pressure-sensitive layer and the substrate layer in the bonding assembly.

[0061] In another optional embodiment, the bonding process includes a metal bonding process. This process involves secondary wafer-level bonding of the bonding assembly and the substrate layer. Specifically, for the bonding assembly and the pressure-sensitive layer to be bonded, a metal sealing ring is formed on the second side of the pressure-sensitive layer opposite to the first side of the bonding assembly and on the substrate layer using magnetron sputtering. The metal bonding process is then used to bond the pressure-sensitive layer and the metal sealing ring on the substrate layer. It should be noted that the wafer-level bonding of the bonding assembly and the substrate layer can refer to the wafer-level bonding of the capping layer and the resonant beam layer, and will not be repeated here.

[0062] In one optional embodiment, at least two of the aforementioned resonant differential pressure sensor structures are formed within the structure of the substrate layer, pressure-sensing layer, vibrating beam layer, and capping layer. Accordingly, after secondary wafer-level bonding of the bonding assembly and the substrate layer using a bonding process, the process includes: dicing using a dicing process to form independent resonant differential pressure sensor structural units. In summary, this embodiment of the invention uses the formed base layer as the basic support layer of the sensor, providing a flat and robust base for the pressure-sensing layer and the vibrating beam layer. This reduces the impact of external vibrations or temperature changes on the internal structure of the sensor, improving measurement stability. Furthermore, the pressure-sensing cavity and resonant cavity structure of the formed pressure-sensing layer enable independent optimization of pressure detection and resonance functions, avoiding mutual interference. The vibrating beam layer covers the pressure-sensing cavity and resonant cavity, communicating with the pressure-sensing layer through the first air vent, ensuring no delay in pressure transmission between the pressure-sensing layer and the vibrating beam layer, improving dynamic response speed. The first cavity of the capping layer and the... The resonant cavity of the laminated layer, along with the hollowed-out area of ​​the vibrating beam, surrounds the vibrating beam within a sealed chamber, effectively protecting the vibrating beam area of ​​the vibrating beam layer. This provides sufficient space for the oscillation of the vibrating beam, ensuring a high quality factor for the quartz resonator and improving the sensor's shock resistance. Furthermore, the second vent connects to the first vent, ensuring efficient and leak-free transmission of the pressure signal from the pressure-sensing layer to the vibrating beam layer, achieving efficient conversion between pressure and frequency. Through two wafer-level bonding processes, product stress is effectively reduced, and stability is improved. The multi-layer stacked design significantly reduces the sensor's size, facilitating applications in space-constrained environments and achieving the advantages of high precision, high stability, and miniaturization.

[0063] Figure 7 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 7As shown, the electronic device may include: a processor 710, a communications interface 720, a memory 730, and a communications bus 740, wherein the processor 710, the communications interface 720, and the memory 730 communicate with each other through the communications bus 740. The processor 710 can call logic instructions in the memory 730 to execute a method for manufacturing a resonant differential pressure sensor. This method includes: forming a substrate layer, a pressure-sensing layer, a resonant beam layer, and a capping layer; forming a pressure-sensing cavity and a resonant cavity on the pressure-sensing layer; forming a first vent and a resonant beam on the resonant beam layer; forming a second vent and a first cavity on the capping layer; and forming a hollow area on the resonant beam. The capping layer, resonant beam layer, and pressure-sensing layer are then wafer-level bonded using a metal bonding process to obtain a bonded assembly. The first cavity and the resonant cavity are connected through the hollow area to form a sealed chamber, enclosing the resonant beam within the sealed chamber. The first vent and the second vent are connected to the pressure-sensing cavity. Finally, the bonded assembly and the substrate layer are then secondary wafer-level bonded using a metal bonding process.

[0064] Furthermore, the logical instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0065] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the manufacturing method of the resonant differential pressure sensor provided by the above methods. The method includes: forming a base layer, a pressure-sensing layer, a vibrating beam layer, and a capping layer respectively; forming a pressure-sensing cavity and a resonant cavity on the pressure-sensing layer; forming a first vent and a vibrating beam on the vibrating beam layer; forming a second vent and a first cavity on the capping layer; and forming a hollow area on the vibrating beam; performing wafer-level bonding on the capping layer, the vibrating beam layer, and the pressure-sensing layer using a metal bonding process to obtain a bonding assembly; wherein the first cavity and the resonant cavity are connected through the hollow area to form a sealed chamber to surround the vibrating beam within the sealed chamber; and the first vent and the second vent are connected to the pressure-sensing cavity; and performing secondary wafer-level bonding on the bonding assembly and the base layer using a metal bonding process.

[0066] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements a method for manufacturing a resonant differential pressure sensor provided by the methods described above. This method includes: forming a substrate layer, a pressure-sensing layer, a vibrating beam layer, and a capping layer, respectively; forming a pressure-sensing region cavity and a resonant region cavity on the pressure-sensing layer; forming a first vent hole and a vibrating beam on the vibrating beam layer; forming a second vent hole and a first cavity on the capping layer; and forming a hollow area on the vibrating beam; performing wafer-level bonding of the capping layer, the vibrating beam layer, and the pressure-sensing layer using a metal bonding process to obtain a bonding assembly; wherein the first cavity and the resonant region cavity are connected through the hollow area to form a sealed chamber, thereby surrounding the vibrating beam within the sealed chamber; and the first vent hole and the second vent hole are connected to the pressure-sensing region cavity; and performing secondary wafer-level bonding of the bonding assembly and the substrate layer using a metal bonding process.

[0067] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0068] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A resonant differential pressure sensor, characterized in that, include: basal layer; A pressure-sensitive layer is disposed on the base layer, and the pressure-sensitive layer is provided with a pressure-sensitive area cavity and a resonant area cavity; A vibrating beam layer is disposed on the pressure-sensitive layer and covers the pressure-sensitive area cavity and the resonant area cavity. The vibrating beam layer is provided with a first air guide hole and a vibrating beam. The first air guide hole is connected to the pressure-sensitive area cavity. The vibrating beam is provided with a hollow area. A capping layer is disposed on the vibrating beam layer. The capping layer is provided with a second air guide hole and a first cavity. The second air guide hole is connected to the first air guide hole. The first cavity and the resonant area cavity are connected through the hollow area to form a sealed chamber, so as to surround the vibrating beam in the sealed chamber.

2. The resonant differential pressure sensor according to claim 1, characterized in that, The pressure-sensing cavity is at least two in number and is symmetrically distributed on the pressure-sensing layer. The resonant cavity is arranged in a one-to-one correspondence with the vibrating beam. The resonant cavity is located between the symmetrically distributed pressure-sensing cavities. The pressure-sensing layer also includes a boss, which is arranged between adjacent resonant cavities.

3. The resonant differential pressure sensor according to claim 2, characterized in that, The thickness of the pressure-sensitive layer ranges from 108 μm to 500 μm, and the measurement range is from 100 kPa to 50.1 MPa; and / or, The height of the boss ranges from 10μm to 60μm; and / or, The height of the boss is equal to the depth of the resonant cavity.

4. The resonant differential pressure sensor according to claim 2, characterized in that, The first air guide hole is provided in a one-to-one correspondence with the pressure-sensing area cavity; The number of vibrating beams is at least one, and the vibrating beams are parallel to the crystal Y-axis of the vibrating beam layer. The crystal Y-axis represents a mechanical axis perpendicular to the crystal facet of the vibrating beam layer.

5. The resonant differential pressure sensor according to claim 4, characterized in that, The vibrating beams consist of three parts: a first edge vibrating beam, a central vibrating beam, and a second edge vibrating beam. These three beams are arranged on the same straight line and parallel to the Y-axis of the crystal. An anchor region is provided between the ends of adjacent vibrating beams. This anchor region is located on the boss and rigidly connected to it. The first edge vibrating beam is used for the routing of the central vibrating beam; The central vibrating beam and the second edge vibrating beam are used to measure pressure.

6. The resonant differential pressure sensor according to claim 4, characterized in that, When the Y-axis direction of the crystal is parallel to the diagonal direction of the vibrating beam layer, the vibrating beams are arranged on the same straight line along the diagonal direction of the vibrating beam layer; or... When the Y-axis direction of the crystal is parallel to the edge direction of the vibrating beam layer, the vibrating beams are arranged on the same straight line along the edge direction of the vibrating beam layer.

7. The resonant differential pressure sensor according to claim 1, characterized in that, The base layer is provided with a second cavity and a third air guide hole. The second cavity is located on the side of the base layer adjacent to the pressure-sensitive layer, and the pressure-sensitive layer covers the second cavity. The third air guide hole penetrates the base layer and is connected to the second cavity.

8. A method for manufacturing a resonant differential pressure sensor, characterized in that, include: A base layer, a pressure-sensitive layer, a vibrating beam layer, and a capping layer are formed respectively. The pressure-sensitive layer has a pressure-sensitive cavity and a resonant cavity. The vibrating beam layer has a first air guide hole and a vibrating beam. The capping layer has a second air guide hole and a first cavity. The vibrating beam has a hollow area. Using a bonding process, the capping layer, the resonant beam layer, and the pressure-sensitive layer are bonded at the wafer level to obtain a bonding assembly; wherein, the first cavity and the resonant region cavity are connected through the hollow area to form a sealed chamber, so as to surround the resonant beam in the sealed chamber, and the first vent hole and the second vent hole are connected to the pressure-sensitive region cavity; Using the bonding process, a secondary wafer-level bonding is performed on the bonding assembly and the substrate layer.

9. The method for manufacturing a resonant differential pressure sensor according to claim 8, characterized in that, The bonding process includes a metal bonding process, which is used to perform wafer-level bonding of the capping layer, the resonant beam layer, and the pressure-sensitive layer, including: Using magnetron sputtering, metal sealing rings are formed on the capping layer and the vibrating beam layer, respectively, and metal sealing rings are formed on the first surface of the vibrating beam layer and the pressure-sensitive layer, respectively. Using a metal bonding process, the metal sealing rings on the capping layer and the vibrating beam layer, as well as the metal sealing rings on the vibrating beam layer and the pressure-sensing layer, are bonded together; Using metal bonding technology, a secondary wafer-level bonding process is performed on the bonding assembly and the substrate layer, including: For the bonding assembly and pressure-sensitive layer to be bonded, a magnetron sputtering process is used to form metal sealing rings on the second side of the pressure-sensitive layer of the bonding assembly opposite to the first side and on the substrate layer, respectively. Then, a metal bonding process is used to bond the pressure-sensitive layer and the metal sealing rings on the substrate layer.

10. The method for manufacturing a resonant differential pressure sensor according to claim 8, characterized in that, The bonding process includes a quartz bonding process, which is used to perform wafer-level bonding of the capping layer, the resonant beam layer, and the pressure-sensitive layer, including: Using a quartz bonding process, the capping layer, the vibrating beam layer, and the pressure-sensitive layer are directly bonded together to obtain a bonded assembly; Using a bonding process, a secondary wafer-level bonding is performed on the bonding assembly and the substrate layer, including: The pressure-sensitive layer and the substrate layer in the bonding assembly are directly bonded using a quartz bonding process.

Images