CN117686131A - Resonant pressure sensor and method for manufacturing the same - Google Patents
Resonant pressure sensor and method for manufacturing the same Download PDFInfo
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- CN117686131A CN117686131A CN202311553017.5A CN202311553017A CN117686131A CN 117686131 A CN117686131 A CN 117686131A CN 202311553017 A CN202311553017 A CN 202311553017A CN 117686131 A CN117686131 A CN 117686131A
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Abstract
The invention relates to the technical field of sensors, and provides a resonant pressure sensor and a manufacturing method thereof, wherein the resonant pressure sensor comprises: the sealing cap layer, the pressure sensing layer and the resonance tuning fork subassembly, the pressure sensing layer is used for responding to the change of input force, the pressure sensing layer is connected the sealing cap layer, be formed with the vacuum chamber between sealing cap layer and the pressure sensing layer, the pressure sensing layer is provided with two at least bosss and two at least first recesses, boss and first recess one-to-one setting, the boss is located the vacuum chamber, first recess sets up in the pressure sensing layer keep away from one side of sealing cap layer, along keeping away from the direction of input force, set gradually boss and first recess. The resonance tuning fork subassembly sets up in the vacuum chamber, and two at least bosss settings are in the opposite side of resonance tuning fork subassembly, resonance tuning fork subassembly is connected the boss, resonance tuning fork subassembly is used for connecting first external circuit, and resonance pressure sensor can be with the tensile and compressive deformation of pressure sensing layer change into bending deformation, improves the sensitivity of pressure sensing layer.
Description
Technical Field
The invention relates to the technical field of sensors, in particular to a resonant pressure sensor and a manufacturing method thereof.
Background
The pressure sensor is characterized in that a pressure sensing membrane senses the pressure of fluid to be measured, a pressure sensitive quartz vibration beam converts the pressure sensing membrane strain caused by the pressure into frequency change and directly outputs frequency proportional to the measured pressure, and a circuit detects the frequency change of the quartz vibration beam and converts the frequency change into an electric signal corresponding to the pressure value to detect the pressure value of the fluid to be measured. The quartz resonance pressure sensor has no speed increment error caused by analog-to-digital conversion, can be compatible with a high-speed digital circuit, has small temperature drift coefficient, and has the advantages of high precision, low cost, small volume and the like.
In the related art, the quartz resonance pressure sensor is a sensitive structure of a tuning fork vibration beam matched with a pressure sensing film, the tuning fork vibration beam is arranged on the pressure sensing film, tensile stress or compressive stress is applied to the tuning fork vibration beam through the pressure sensing film, the change of the resonance frequency of the tuning fork vibration beam is realized, but the tensile or compressive deformation can generate local stress concentration on the pressure sensing film, and the damage of the pressure sensing film can be caused, so that the sensitivity of the resonance pressure sensor is difficult to improve. Meanwhile, the sensitive structure of the all-quartz material adopts a round structure, so that the loss at the pressure sensing film is large, and the detection precision is difficult to improve.
Disclosure of Invention
The invention provides a resonant pressure sensor, which is used for solving the defect that the detection precision and sensitivity of the resonant pressure sensor are difficult to improve in the prior art.
Embodiments of the first aspect of the present invention provide a resonant pressure sensor,
sealing the cap layer;
the pressure sensing layer is used for sensing the change of input force, the pressure sensing layer is connected with the sealing cap layer, a vacuum cavity is formed between the sealing cap layer and the pressure sensing layer, the pressure sensing layer is provided with at least two bosses and at least two first grooves, the bosses and the first grooves are arranged in a one-to-one correspondence manner, the bosses are positioned in the vacuum cavity, the first grooves are arranged on one side, far away from the sealing cap layer, of the pressure sensing layer, and the bosses and the first grooves are sequentially arranged along the direction far away from the input force;
and the resonant tuning fork assembly is arranged in the vacuum chamber, at least two bosses are arranged on opposite sides of the resonant tuning fork assembly, the resonant tuning fork assembly is connected with the bosses, and the resonant tuning fork assembly is used for being connected with a first external circuit.
According to one embodiment of the invention, two bosses are provided, two first grooves are provided, two bosses are oppositely arranged at two sides of the input force, and the input direction of the input force is perpendicular to the connecting line direction of the two bosses.
According to one embodiment of the present invention, a second groove is formed on a side of the pressure sensing layer facing the vacuum chamber, the boss is disposed in the second groove, and the first groove and the second groove are disposed at intervals.
According to an embodiment of the present invention, a first sidewall of the first groove adjacent to the second groove is parallel to a second sidewall of the second groove adjacent to the first groove, and a distance between the first sidewall and the second sidewall is greater than or equal to 100 micrometers and less than or equal to 1800 micrometers.
According to an embodiment of the present invention, the depth of the first groove and the height of the boss are the same, and/or the depth of the second groove and the height of the boss are the same.
According to an embodiment of the present invention, the thickness of the pressure sensing layer is greater than or equal to 220 micrometers and less than or equal to 1920 micrometers, and the height of the boss is greater than or equal to 120 micrometers and less than or equal to 240 micrometers.
According to an embodiment of the present invention, a distance between two first grooves is 5000 micrometers or more and 7000 micrometers or less, and an opening end length of the first grooves is 1000 micrometers or more and 2000 micrometers or less.
According to one embodiment of the present invention, the tuning fork assembly includes a tuning fork vibrating beam assembly, a first folding beam and a second folding beam, one end of the tuning fork vibrating beam assembly is connected to the boss through the first folding beam, the other end of the tuning fork vibrating beam assembly is connected to the boss through the second folding beam, and the first folding beam, the second folding beam and the tuning fork vibrating beam assembly are suspended.
According to an embodiment of the present invention, the tuning fork assembly further includes a boss abutting part, at least one of the first folded beam and the second folded beam is connected to the boss through the boss abutting part, two bosses are provided, two boss abutting parts are provided, the bosses and the boss abutting parts are provided in one-to-one correspondence, and the tuning fork vibrating beam assembly is provided between the two boss abutting parts.
An embodiment of a second aspect of the present invention provides a method of manufacturing a resonant pressure sensor comprising an embodiment as described in any one of the preceding embodiments, comprising:
Forming the boss on the pressure sensing layer;
disposing the resonant tuning fork assembly on the pressure sensing layer, wherein the resonant tuning fork assembly is coupled to the boss;
and arranging the sealing cap layer on the pressure sensing layer, wherein the sealing cap layer is connected with the pressure sensing layer.
The above technical solutions in the embodiments of the present invention have at least one of the following technical effects:
(1) The resonant pressure sensor provided by the embodiment of the invention is provided with the boss and the first groove in sequence along the direction far away from the input force. At least two bosses are provided on opposite sides of the resonant tuning fork assembly, i.e. both bosses and first grooves are provided on opposite sides of the resonant tuning fork assembly. When the input force is input, the boss is rotated towards the direction of the first groove, so that the pressure sensing layer is bent and deformed. Compared with the pressure sensing layer which is subjected to tension-compression deformation under the action of tension-compression stress, the pressure sensing layer is subjected to bending deformation, and the whole surface of the pressure sensing layer can participate in the pressure sensing deformation, so that the surface area of the induction deformation can be increased. In this embodiment, under the action of the same input force, the bending deformation pressure sensing layer can extend to multiple directions relative to the deformation of the tensile deformation pressure sensing layer in the length direction, so that the deformation amount is larger, that is, the deformation degree of the pressure sensing layer is larger, and the sensitivity of the pressure sensing layer to the input force can be improved.
(2) The pressure sensing layer is provided with a boss, and the resonance tuning fork component is connected to the boss. The input force is used for driving the dynamic pressure layer to generate strain so that the bosses are close to each other or far away from each other, the tuning fork vibration beam assembly is strained through the bosses, the frequency of the tuning fork vibration beam assembly is changed, and the first external circuit detects the frequency to detect the magnitude of the input force. Compared with the resonant tuning fork assembly connected to the pressure sensing layer of the planar structure, the boss can form a concentrated force application point relative to the plane under the action of the same input force, so that the transmission of pressure is optimized. The deformation of the pressure sensing layer can be increased through the boss, and the strain degree of the pressure sensing layer is improved, so that the response of the resonant tuning fork assembly to the input force is quick, and the detection precision and sensitivity of the resonant tuning fork assembly to the input force are high.
(3) The first folding beam and the second folding beam are combined with the boss to form a lever multiplication structure, so that the input force can be amplified, the acting force of the input force on the tuning fork vibrating beam assembly is improved, the acting force received by the tuning fork vibrating beam assembly is large, the deformation is large, and the detection precision and the sensitivity of the tuning fork vibrating beam assembly are improved.
Drawings
In order to more clearly illustrate the invention or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a first resonant pressure sensor of the prior art;
FIG. 2 is a schematic diagram of a second prior art resonant pressure sensor;
FIG. 3 is a schematic diagram of a third prior art resonant pressure sensor;
FIG. 4 is a cross-sectional view of a first resonant pressure sensor provided by an embodiment of the present invention;
FIG. 5 is a cross-sectional view of a second resonant pressure sensor provided by an embodiment of the present invention;
FIG. 6 is a top view of a resonant pressure sensor with a cap layer removed according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a resonant tuning fork assembly provided by an embodiment of the invention;
FIG. 8 is a top view of a resonant pressure sensor with the cap layer and the tuning fork assembly removed, as provided by an embodiment of the present invention;
FIG. 9 is a cross-sectional view of a first pressure sensitive layer and a gold-plated electrode layer provided by an embodiment of the present invention;
FIG. 10 is a cross-sectional view of a second pressure sensitive layer and a gold-plated electrode layer provided by an embodiment of the present invention;
FIG. 11 is a top view of a guide layer provided by an embodiment of the present invention;
FIG. 12 is a cross-sectional view of a guide layer provided by an embodiment of the present invention;
fig. 13 is a bottom view of a sealing cap layer according to an embodiment of the present invention.
Reference numerals:
1. A vibrating beam; 2. a pressure sensing film; 3. a metal counterweight; 4. quartz vibration beam; 5. a metallic flexible head; 6. a metal bourdon tube; 7. a vacuum chamber; 8. inputting pressure from outside; 9. a temperature measuring tuning fork; 10. a left sensing film; 11. left induction trimming; 12. right induction trimming; 13. a right sensing film; 14. a cylindrical vacuum chamber; 15. a resonator upper electrode; 16. a harmonic oscillator; 17. a resonator lower electrode; 18. an end cover plate; 19. an excitation circuit; 20. a frequency measurement circuit; 21. a sensitive structure;
100. sealing the cap layer; 110. a vacuum chamber; 120. a getter layer; 130. a cavity;
200. a pressure sensitive layer; 210. a boss; 220. a second piezometric excitation pad; 230. a third piezometric excitation pad; 240. a second temperature-measuring excitation pad; 250. a third temperature-measuring excitation pad; 260. an electrode lead; 270. a first groove; 280. a second groove; 290. a gold-plated electrode layer;
300. a resonant tuning fork assembly; 301. a first excitation electrode; 311. tuning fork vibration beam; 312. a first tuning fork junction block; 313. a second tuning fork junction block; 314. a first tuning fork stress isolation beam; 315. a second tuning fork stress isolation beam; 316. a first folding beam junction block; 317. a second folded beam junction block; 321. a first folding beam; 322. a second folding beam; 331. a first boss interfacing part; 3311. a first piezometric excitation pad; 332. a second boss interfacing part; 3321. a first temperature measurement excitation pad; 333. a wire; 340. a temperature measuring tuning fork; 341. a second excitation electrode; 350. a counterweight tuning fork;
400. A guiding layer; 410. a pressure sensing chamber; 420. a guide channel; 430. a first isolation groove; 440. a second isolation groove;
510. a first glass paste; 520. a second glass paste; 530. and a third glass paste.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the embodiments of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In describing embodiments of the present invention, it should be noted that, unless explicitly stated and limited otherwise, the terms "coupled," "coupled," and "connected" should be construed broadly, and may be either a fixed connection, a removable connection, or an integral connection, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in embodiments of the present invention will be understood in detail by those of ordinary skill in the art.
In embodiments of the invention, unless expressly specified and limited otherwise, a first feature "up" or "down" on a second feature may be that the first and second features are in direct contact, or that the first and second features are in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the embodiments of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
Between the description of the resonant pressure sensor provided by the embodiment of the invention, the working principle of the resonant pressure sensor is described.
Referring to fig. 1, a vibration beam 1 is bonded to a pressure sensitive film. When the external force P is input, the external force P causes the pressure-sensitive film 2 to be strained, and the pressure-sensitive film 2 tends to crack to both sides. The pressure sensing film 2 on the left side of the external force P moves leftwards, and the pressure sensing film 2 on the right side of the external force P moves rightwards, so that the vibration beam 1 adhered to the pressure sensing film 2 senses tensile stress. The vibration beam 1 receives the tensile stress, and the resonance frequency of the vibration beam 1 increases.
When the external force P becomes smaller, the pressure sensing film 2 on the left side of the external force P moves to the right, and the pressure sensing film 2 on the right side of the external force P moves to the left, so that the vibration beam 1 adhered to the pressure sensing film 2 senses compressive stress. The vibration beam 1 receives the effect of pressure stress, and the resonance frequency of the vibration beam 1 is reduced.
The change in the resonance frequency of the vibration beam 1 can reflect the magnitude of the input force. The vibration beam 1 is connected to an external circuit, so that the resonance frequency of the vibration beam 1 is detected by the external circuit to detect the magnitude of the external force P.
In the description of the resonant pressure sensor provided in the embodiment of the present invention, a quartz resonant pressure sensor is taken as an example, and a resonant pressure sensor in the related art is described.
The quartz resonance pressure sensor sensitive structure can be divided into a quartz vibration beam and metal pressure sensing film structure and a quartz vibration beam and quartz pressure sensing film structure, wherein the quartz vibration beam and metal pressure sensing film structure scheme is adopted by the U.S. penos company, and the quartz vibration beam and quartz pressure sensing film full-quartz structure scheme is adopted by the U.S. Quartz zdyne company and the Japanese EPSON company.
The application of the quartz resonance pressure sensor is expanded from the aviation fields of an aircraft air data system, a pressure calibration system, an engine test and the like to the petrochemical field of industrial process monitoring and the like, and the quartz resonance pressure sensor provided by the embodiment of the invention is mainly oriented to tactical application occasions with large impact and strong vibration, and the typical mechanical environment is (1) random vibration: the bandwidth is 20 Hz-2 kHz, and the effective value is 6.06g; (2) impact: half sine peak 200g, half wave time 6ms.
The U.S. penuosi company was established in 1972, and was initiated by Jerome m.para, para, by utilizing the engineering experience of developing digital force sensors in the early years, and conducted the development and production of quartz resonance pressure sensors, and the pressure sensor sensitive gauge head developed by the company adopts a combined structure of a metal pressure sensing element and a Dan Yingzhen beam.
As shown in fig. 2, the pressure sensor-sensitive gauge head includes: the device comprises a metal counterweight 3, a quartz vibration beam 4, a metal flexible head 5, a metal Bowden tube 6, a vacuum chamber 7 and a temperature measuring tuning fork 9.
The metal Bowden tube 6 and the metal flexible head 5 are adopted as metal pressure sensing elements, the quartz vibration beam 4 is rigidly connected with the metal pressure sensing elements, when the external input pressure 8 is changed, the metal pressure sensing elements are caused to deform, so that the axial stress of the quartz vibration beam 4 with fixed two ends is caused to change, the output frequency of the quartz vibration beam 4 is caused to change, the pressure measurement is realized, and the self-balancing weight and the impact protection device are further arranged in the gauge head, so that the sensor can work in high overload, impact and vibration environments. The product is applied to an atmospheric data system, an aeroengine detection, a pressure calibration device, a satellite micro-propulsion measurement system, a tsunami monitoring system and the like.
The structure has the advantages that the product sensitivity can be improved by adopting a metal structure film structure, and the defect that the metal thermal expansion coefficient is not matched with the Dan Yingzhen beam 4 by adopting a metal pressure sensing film structure, so that zero drift is caused by thermal stress.
The company Quartzdyne in the united states was established in 1990, was created as Errol p.eernisse, which was operated in Sandia laboratories in the united states for an early time, was engaged in radiation resistance studies of piezoelectric and semiconductor devices, was initiated in 1979, and was engaged in the development and production of quartz resonant pressure sensors for measuring acceleration, pressure and temperature. The product is applied to the fields of underground oil and gas industry, logging and drilling industry, submarine detection, process control, energy development and the like.
The sensitive structure of the quartz resonance pressure sensor developed by the company adopts an all-quartz scheme, which is a quartz resonator working in a thickness shear mode, as shown in fig. 3, and the sensitive gauge head comprises: a left induction film 10, a left induction trimming 11, a right induction trimming 12, a right induction film 13, a cylindrical vacuum chamber 14, a harmonic oscillator upper electrode 15, a harmonic oscillator 16, a harmonic oscillator lower electrode 17, an end cover plate 18, an excitation circuit 19, a frequency measurement circuit 20 and a sensitive structure 21.
The quartz resonance pressure sensor consists of an AT cut disc-shaped resonator, a thin-walled cylinder with trimming edges and an end cover plate 18, wherein the center part of the thin-walled cylinder is separated by a resonance disc, the left and right trimming edges of the outer surface of the quartz cylinder sense pressure, so that the radial compressive stress of the disc-shaped quartz resonator is changed, and the resonance frequency is changed, so that the pressure measurement is realized.
The structure has the advantages that the full quartz structure is adopted, the material matching performance of the sensitive structure is good, the traditional grinding processing is adopted, the middle-low range ultrathin pressure sensing film is unsuitable to process, the single processing efficiency is low, and the method is unsuitable for mass production.
From this, the existing quartz resonance pressure sensor has the following sensitive structure:
1. the existing metal wave lamp tube and Dan Yingzhen beam structure cannot solve the problem of thermal expansion coefficient matching, and as a plurality of materials are adopted, the thermal expansion coefficients of the materials cannot be completely matched, and the matching of the thermal expansion coefficients cannot be effectively ensured by adopting process glue bonding, so that the temperature drift coefficient is relatively large when the temperature varies in the whole temperature range;
2. the existing full-quartz sensitive structure adopts a circular structure, so that the loss at the base is larger, the manufacturing process of the integrated structure is difficult, and the ultrathin pressure-sensitive film is difficult to process;
3. The existing sensitive structure lacks an effective temperature measuring element, and the effective measurement of the core temperature of the sensitive structure cannot be realized by adopting a separated temperature measuring tuning fork or a temperature measuring crystal oscillator;
4. the existing sensitive structure only depends on the design of the pressure sensing film and the rigidity of the vibration beam to realize limit stop, so that the influence of external vibration and impact on the sensitive structure is prevented, and the soft landing of the resonant structure cannot be realized, so that under the condition of large vibration or large impact, the harmonic oscillator is extremely easy to break, and the whole meter is further invalid.
Next, a resonant tuning fork sensor according to an embodiment of the first aspect of the present invention will be described with reference to fig. 4 to 13.
Referring to fig. 5 and 6, the present invention provides a resonant pressure sensor of an embodiment of the first aspect, comprising a cap layer 100, a pressure sensing layer 200 and a resonant tuning fork assembly 300.
The pressure sensing layer 200 is used for sensing the change of input force, the pressure sensing layer 200 is connected with the sealing cap layer 100, a vacuum cavity 110 is formed between the sealing cap layer 100 and the pressure sensing layer 200, the pressure sensing layer 200 is provided with at least two bosses 210 and at least two first grooves 270, the bosses 210 and the first grooves 270 are arranged in a one-to-one correspondence manner, the bosses 210 are positioned in the vacuum cavity 110, the first grooves 270 are arranged on one side, far away from the sealing cap layer 100, of the pressure sensing layer 200, and the bosses 210 and the first grooves 270 are sequentially arranged along the direction far away from the input force. The resonant tuning fork assembly 300 is disposed within the vacuum chamber 110, at least two bosses 210 are disposed on opposite sides of the resonant tuning fork assembly 300, the resonant tuning fork assembly 300 is coupled to the bosses 210, and the resonant tuning fork assembly 300 is adapted to be coupled to a first external circuit.
In the present embodiment, the boss 210 and the first groove 270 are sequentially provided in a direction away from the input force. At least two bosses 210 are provided on opposite sides of the resonant tuning fork assembly 300, i.e., the bosses 210 and the first recess 270 are provided on opposite sides of the resonant tuning fork assembly 300. When an input force is input, the boss 210 is rotated in the direction of the first groove 270, and the pressure-sensitive layer 200 is bent and deformed.
Compared with the pressure sensing layer 200 which is pulled and pressed to deform under the action of the pulling and pressing stress, the pressure sensing layer 200 is bent and deformed, and the whole surface of the pressure sensing layer 200 can participate in the pressure sensing deformation, so that the surface area of the induction deformation can be increased. In this embodiment, under the action of the same input force, the bending deformation of the pressure sensing layer 200 can extend in multiple directions relative to the deformation of the tensile deformation of the pressure sensing layer 200 in the length direction, so that the deformation amount is larger, that is, the deformation degree of the pressure sensing layer 200 is larger, and the sensitivity of the pressure sensing layer 200 to the input force can be improved.
Preferably, in conjunction with fig. 5, two bosses 210 are provided, two first grooves 270 are provided, two bosses 210 are oppositely provided at two sides of the input force, and the input direction of the input force is perpendicular to the connecting line direction of the two bosses 210.
In this embodiment, the input force is located between two bosses 210, and the bosses 210 and the first grooves 270 are sequentially disposed in a direction away from the input force. In connection with fig. 5, i.e. the input force is arranged in the middle of the two bosses 210, a first recess 270 is arranged on the left side of the left boss 210, and a first recess 270 is arranged on the right side of the right boss 210.
When an input force is input, the input force presses the pressure sensing layer 200 from the bottom up, and the pressing position is located between the two bosses 210. At this time, the pressure sensitive layer 200 is strained, and the bosses 210 are spaced apart from each other.
Taking the right boss 210 as an example, a first groove 270 is provided at the right side of the right boss 210. When the input force is input, the right boss 210 rotates in the direction of the right first groove 270, i.e., the right boss 210 rotates clockwise.
Taking the left boss 210 as an example, a first groove 270 is provided at the left side of the left boss 210. When an input force is input, the left boss 210 rotates in the direction of the left first groove 270, i.e., the left boss 210 rotates counterclockwise.
In this embodiment, the right boss 210 rotates clockwise, and the left boss 210 rotates counterclockwise, so that the sensing film is bent and deformed. The boss 210 and the first groove 270 are matched to improve the deformation degree of the pressure sensing layer 200, so that the sensitivity of the pressure sensing layer 200 to input force is increased, and the detection precision of the resonant pressure sensor is further improved.
Wherein, when there is an assembly stress or thermal stress transfer induced compressive layer 200, the flexural deformation of the compressive layer 200 can disperse the stress, thereby realizing the absorption of the stress and reducing the influence of the stress on the compressive layer 200 and the tuning fork assembly 300. Meanwhile, when vibration or impact is transmitted to the pressure sensing layer 200, the bending deformation of the pressure sensing layer 200 can absorb the energy of the vibration or impact and slow down the energy transmission speed of the vibration or impact, thereby realizing the protection of the pressure sensing layer 200 and the resonant tuning fork assembly 300 and avoiding the failure of the resonant pressure sensor due to the fracture of the resonant tuning fork assembly 300.
It should be noted that, the direction of the input force may be perpendicular to the connecting line direction of the two bosses 210, or may form an acute angle or an obtuse angle with the connecting line direction of the two bosses 210, and the direction of the input force may be located between the two bosses 210, which is not limited herein.
The side of the pressure sensing layer 200 facing the vacuum chamber is formed with a second groove 280, the boss 210 is disposed in the second groove 280, and the first groove 270 is disposed at a distance from the second groove 280. Referring to fig. 5, the boss 210 is disposed in the second groove 280, and the second groove 280 can reduce the thickness of the pressure sensitive layer 200, thereby reducing the distance between the boss 210 and the first groove 270. In this embodiment, the distance between the boss 210 and the first groove 270 is small, and when the boss 210 rotates in the direction of the first groove 270, the resistance to rotation of the boss 210 is small, so that the deformation amount of the bending deformation of the pressure sensing layer 200 can be further improved, and the sensitivity of the pressure sensing layer 200 can be further improved.
The first sidewall of the first groove 270 adjacent to the second groove 280 is parallel to the second sidewall of the second groove 280 adjacent to the first groove 270. Referring to fig. 5, the first sidewall is parallel to the second sidewall, which can improve the rotational stability of the boss 210 and help reduce the inclination or offset of the boss 210 during rotation. The distance between the first side wall and the second side wall is greater than or equal to 100 micrometers and less than or equal to 1800 micrometers, so that resistance in the rotation process of the boss 210 can be reduced, the smoothness of rotation of the boss 210 is improved, and the stability of bending deformation of the pressure sensing layer 200 is further improved.
Referring to fig. 5, the depth of the first groove 270 is the same as the height of the boss 210, which helps to maintain the stability of the pressure sensing layer 200, and simultaneously, the first groove 270 and the boss 210 have a simple structure, are convenient to form, and can simplify the manufacturing process. Of course, in other embodiments, the depth of the first groove 270 and the height of the boss 210 may be different.
The cross-sectional area of the first groove 270 may have a trapezoid shape, a rectangular shape, a pentagonal shape, or the like. The cross-sectional area of the boss 210 may have a trapezoid shape, a rectangular shape, a pentagonal shape, or the like. The cross-sectional area of the first groove 270 may have the same shape as the cross-sectional area of the boss 210 or may be different.
Referring to fig. 5, the depth of the second groove 280 is the same as the height of the boss 210, which helps to maintain the stability of the pressure sensing layer 200, and simultaneously, the first groove 270 and the boss 210 have a simple structure, are convenient to form, and can simplify the manufacturing process. Of course, it is also possible that the height of the boss 210 is greater than the depth of the first groove 270, and the top surface of the boss 210 is higher than the top surface of the first groove 270.
Of course, the depth of the first groove 270, the depth of the second groove 280 and the height of the boss 210 may be the same, which can effectively improve the structural consistency of the pressure sensing layer 200, make the deformation of the pressure sensing layer 200 more controllable and predictable, and simultaneously improve the stability and reliability of the deformation of the pressure sensing layer 200 during bending deformation.
Preferably, the thickness of the pressure sensing layer 200 is greater than or equal to 220 micrometers and less than or equal to 1920 micrometers, and the height of the boss 210 is greater than or equal to 120 micrometers and less than or equal to 240 micrometers, so that not only can the strength of the pressure sensing layer 200 be ensured to meet the requirement, but also the boss 210 can be matched with the first groove 270 to rotate, and the bending deformation of the pressure sensing layer 200 is realized.
Preferably, the depth of the first grooves 270 is 120 microns or more and 240 microns or less. The depth of the first groove 270 may be the same as or different from the height of the boss 210. Similarly, the depth of the second groove 280 is greater than or equal to 120 microns and less than or equal to 240 microns. The depth of the second groove 280 may be the same as the height of the boss 210 or may be different.
Preferably, the distance between the two first grooves 270 is 5000 micrometers or more and 7000 micrometers or less, and the open end length of the first grooves 270 is 1000 micrometers or more and 2000 micrometers or less. Referring to fig. 10, e12 is the distance between the two first grooves 270, and e11 is the length of the open ends of the grooves.
It should be noted that, the distance between the two first grooves 270 may be the distance between the farthest ends of the two first grooves 270, for example: referring to fig. 10, the end of the two first grooves 270 furthest from each other is denoted as e12 in the figure; or may be the distance between the two central axes of the two first grooves 270; it is also possible that the two first grooves 270 are spaced apart from the nearest end, such as: in connection with fig. 10, there may be a distance between the right end of the left first groove 270 and the left end of the right first groove 270.
The resonant tuning fork assembly 300 is disposed in the vacuum chamber 110, the boss 210 is disposed at an opposite side of the resonant tuning fork assembly 300, the resonant tuning fork assembly 300 is used for connecting a first external circuit, the resonant tuning fork assembly 300 includes a tuning fork vibrating beam assembly, a first folding beam 321 and a second folding beam 322, one end of the resonant tuning fork assembly 300 is connected with the boss 210 through the first folding beam 321, the other end of the resonant tuning fork assembly 300 is connected with the boss 210 through the second folding beam 322, and the resonant tuning fork assembly 300 is suspended.
The input force in this embodiment is used to drive the dynamic pressure layer 200 to generate strain, so that the bosses 210 are close to each other or far away from each other, the tuning fork vibration beam assembly is strained through the bosses 210, the frequency of the tuning fork vibration beam assembly is changed, and the first external circuit detects the frequency to detect the magnitude of the input force.
In the resonant pressure sensor provided by the embodiment of the invention, the pressure sensing layer 200 is provided with the boss 210, the pressure sensing layer 200 is used for sensing the change of the input force, and the resonant tuning fork assembly 300 is connected with the boss 210 of the pressure sensing layer 200. The tuning fork assembly 300 includes a tuning fork vibrating beam assembly, a first folding beam 321 and a second folding beam 322, and the tuning fork vibrating beam assembly is connected to the boss 210 through the first folding beam 321 and the second folding beam 322. According to the resonant pressure sensor provided by the embodiment of the invention, the tuning fork vibrating beam component is connected with the first folding beam 321 and the second folding beam 322, when vibration or impact is transmitted to the first folding beam 321 and the second folding beam 322, the first folding beam 321 and the second folding beam 322 can be bent or elastically deformed, so that stress is absorbed, the first folding beam 321 and the second folding beam 322 can absorb energy, vibration isolation is realized, damage of external impact to the tuning fork vibrating beam component can be effectively prevented, protection of the resonant pressure sensor is realized, and positive production work of the resonant pressure sensor is ensured.
It will be appreciated that during assembly there may be assembly stresses, i.e., during assembly, which may result in the pressure sensing layer 200 being over-positioned due to an imperfect fit or other factors, which may result in distortion of the pressure sensing layer 200. In this embodiment, the first folding beam 321 and the second folding beam 322 not only can reduce the influence of vibration or impact on the tuning fork vibration beam assembly, but also can effectively absorb the assembly stress, and reduce the influence of the assembly stress on the tuning fork vibration beam assembly.
At the same time, temperature variations can cause stresses inside the object. If the object is affected by temperature change, internal stress is generated in the object due to thermal expansion or contraction, i.e. thermal stress. In this embodiment, the tuning fork assembly 300 is a quartz tuning fork assembly 300, and when the resonant pressure sensor performs a high-low temperature test, the pressure sensing layer 200 is distorted due to the existence of thermal stress, and the thermal stress can be absorbed through the first folding beam 321 and the second folding beam 322, so that the influence of the thermal stress on the tuning fork assembly is reduced.
Wherein the pressure sensing layer 200 is provided with a boss 210, and the resonant tuning fork assembly 300 is coupled to the boss 210. The input force is used to drive the dynamic pressure layer 200 to generate strain so that the bosses 210 are close to or far from each other, so that the tuning fork vibration beam assembly is strained through the bosses 210, the frequency of the tuning fork vibration beam assembly is changed, and the first external circuit detects the magnitude of the input force by detecting the frequency. Compared with the resonant tuning fork assembly 300 connected to the pressure sensing layer 200 with a planar structure, the boss 210 can form a concentrated force application point relative to the plane under the action of the same input force, so that the transmission of pressure is optimized. The boss 210 has a simple structure, can increase the deformation amount of the pressure sensing layer 200, improve the sensitivity of the pressure sensing layer 200, and improve the strain degree of the resonant tuning fork assembly 300, so that the resonant tuning fork assembly 300 has a fast response to the input force, and the resonant tuning fork assembly 300 has high detection accuracy and sensitivity to the input force.
The sensitivity is understood as a degree of response to an input force when the pressure sensitive layer 200 receives the input force. For example, the greater the degree of deformation and the greater the amount of deformation of the pressure-sensitive layer 200 under the same input force, the higher the sensitivity of the pressure-sensitive layer 200 to the input force. Conversely, if the deformation degree of the pressure-sensitive layer 200 is smaller and the deformation amount is smaller, the pressure-sensitive layer 200 increases the sensitivity to the input force to be smaller.
Referring to fig. 6, the working principle of the resonant pressure sensor in this embodiment will be described by taking an example in which two bosses 210 are provided, a tuning fork vibrating beam assembly is provided between the two bosses 210, and the direction of the input force is perpendicular to the connecting line direction of the two bosses 210.
Referring to fig. 6, a boss 210 is provided on the left side of the tuning fork beam assembly, and a boss 210 is also provided on the right side of the tuning fork beam assembly.
When an input force is input, the input force presses the pressure sensing layer 200 from the bottom up, and the pressing position is located between the two bosses 210. At this time, the pressure sensitive layer 200 is strained, the bosses 210 are apart from each other, the left boss 210 is moved leftwards, and the right boss 210 is moved rightwards. That is, the pressure sensitive layer 200 is pulled to the left and right sides, and the pressure sensitive layer 200 is deformed by tensile stress.
The left boss 210 moves leftwards, the left boss 210 is connected with a first folding beam 321 and a second folding beam 322, the left first folding beam 321 pulls the tuning fork vibrating beam assembly leftwards and downwards, and the left second folding beam 322 pulls the tuning fork vibrating beam assembly leftwards and upwards. The left boss 210 moves rightwards, the right boss 210 is connected with a first folding beam 321 and a second folding beam 322, the first folding beam 321 on the right pulls the tuning fork vibrating beam assembly rightwards and downwards, and the second folding beam 322 on the right pulls the tuning fork vibrating beam assembly rightwards and upwards. The upper side of the tuning fork vibrating beam assembly receives downward force through the acting forces of the first folding beam 321 and the second folding beam 322 at the left side and the right side, the lower side of the tuning fork vibrating beam assembly receives upward force, the tuning fork vibrating beam assembly receives compressive stress, and the tuning fork resonant frequency is reduced.
Referring to fig. 6, when the input force becomes smaller, the pressure sensing layer 200 is strained, the bosses 210 are adjacent to each other, the left boss 210 is moved rightward, and the right boss 210 is moved leftward. That is, the left and right sides of the pressure sensitive layer 200 move to the middle, and the pressure sensitive layer 200 is deformed by compressive stress.
The left boss 210 moves rightward, the left first folded beam 321 pushes the tuning fork vibrating beam assembly rightward and upward, and the left second folded beam 322 pushes the tuning fork vibrating beam assembly rightward and downward. The boss 210 on the right side moves leftwards, the first folded beam 321 on the right side pushes the tuning fork vibrating beam assembly leftwards and upwards, and the second folded beam 322 on the right side pushes the tuning fork vibrating beam assembly leftwards and downwards. The upper side of the tuning fork vibrating beam assembly receives upward force through the acting forces of the first folding beam 321 and the second folding beam 322 at the left side and the right side, the lower side of the tuning fork vibrating beam assembly receives downward force, the tuning fork vibrating beam assembly receives tensile stress, and the tuning fork resonant frequency is increased.
In this embodiment, the first folding beam 321 and the second folding beam 322 combine the boss 210 to form a lever multiplication structure, and compared with the input force which directly acts on the tuning fork vibration beam assembly through the pressure sensing layer 200, the lever multiplication structure of this embodiment can realize the amplification of the input force through the first folding beam 321 and the second folding beam 322, thereby improving the acting force of the input force on the tuning fork vibration beam assembly, the acting force received by the tuning fork vibration beam assembly is large, the deformation amount is large, and the detection precision and the sensitivity of the tuning fork vibration beam assembly are improved.
The vacuum chamber 110 is formed between the cap layer 100 and the pressure sensing layer 200, and the vacuum environment not only helps to isolate the influence of external vibration and impact on the resonant tuning fork assembly 300, but also prevents impurities (such as gas or liquid that may affect the detection of the resonant tuning fork assembly 300) from entering the vacuum chamber 110, thereby further improving the sensitivity and accuracy of the detection of the resonant tuning fork assembly 300. Of course, in other embodiments, the vacuum chamber 110 is not formed between the cap layer 100 and the pressure sensing layer 200, and an installation space for the tuning fork assembly 300 may be formed between the cap layer 100 and the pressure sensing layer 200.
Referring to fig. 4, the side of the cap layer 100 facing the vacuum chamber 110 is provided with a getter layer 120, and the getter layer 120 serves to maintain the vacuum of the vacuum chamber 110. In this embodiment, the presence of the getter layer 120 may help maintain the vacuum of the vacuum chamber 110, reducing the interference of the gas with the resonant tuning fork assembly 300, thereby improving the accuracy and stability of the measurement.
It will be appreciated that there may be 2 bosses 210, with the resonant tuning fork assembly 300 disposed between 2 bosses 210. The number of the bosses 210 may be 3, 4, etc., for example, when the number of the bosses 210 is 3, one of the 2 bosses 210,2 may be provided on one side of the tuning fork assembly 300 to be connected to one end of the tuning fork assembly through the first folded beam 321, and the other of the 2 bosses 210 may be connected to the other end of the tuning fork assembly through the second folded beam 322; and 1 boss 210,1 bosses 210 are arranged on the other side of the tuning fork vibration beam assembly and are connected with the tuning fork vibration beam assembly through a first folding beam 321 and a second folding beam 322. When an input force is input, the 3 bosses 210 can be moved away from each other to strain the tuning fork bridge assembly.
The number of the bosses 210 may be set according to actual needs, and may be set to 2, 3, 4, etc., which is not limited herein. Next, the resonant tuning fork assembly 300 according to the embodiment of the present invention will be described by taking the example that 2 bosses 210 are provided.
Referring to fig. 6 and 7, the resonant tuning fork assembly 300 further includes a boss interfacing part through which at least one of the first folded beam 321 and the second folded beam 322 is coupled to the boss 210. The boss 210 sets up two, and boss interfacing part sets up two, and boss 210 and boss interfacing part one-to-one set up, and tuning fork vibration beam assembly sets up between two boss interfacing parts. In this embodiment, the two bosses 210 and the boss abutting parts are arranged in a one-to-one correspondence, so that the connection strength and stability of the resonant tuning fork assembly 300 and the boss 210 can be improved, and the loosening of the resonant tuning fork assembly 300 can be reduced. The arrangement of the boss interfacing parts can simplify the manufacturing and installation process with respect to the coupling of the first and second folded beams 321 and 322 to the boss 210, facilitate the assembly between the tuning fork assembly 300 and the boss 210, reduce the complexity of the assembly, and contribute to the improvement of the production efficiency.
At least one of the first folding beam 321 and the second folding beam 322 is connected with the boss 210 through a boss butt joint part, the first folding beam 321 can be connected with the boss 210 through the boss butt joint part, the second folding beam 322 can also be connected with the boss 210 through the boss butt joint part, and the first folding beam 321 and the second folding beam 322 can also be connected with the boss 210 through the boss butt joint part, so that the connection strength is effectively improved. Of course, the first folding beam 321 and the second folding beam 322 may be connected to the boss 210 through the boss butt-joint part, or may be directly connected to the boss 210, and may be set according to actual requirements.
It should be noted that, the first folding beam 321 and the second folding beam 322 may be at the same height as the tuning fork vibrating beam assembly, that is, the first folding beam 321, the second folding beam 322 and the tuning fork vibrating beam assembly are located on the same plane, and the pressure transmission effect of the first folding beam 321 and the second folding beam 322 is good. Of course, the tuning fork beam assembly may be higher than the boss butt-joint part, or the tuning fork beam assembly may be lower than the boss butt-joint part, and the first folding beam 321 and the second folding beam 322 may extend up and down.
Referring to fig. 6, the boss interfacing part, the first folded beam 321, and the second folded beam 322 are symmetrically distributed with the tuning fork vibrating beam assembly as a center line. In this embodiment, the symmetrical design may enable the resonant tuning fork assembly 300 to receive a uniformly distributed force when pressure is applied, that is, the acting force of the input force on the tuning fork vibrating beam assembly is uniform, which is helpful to improve the stability of deformation of the tuning fork vibrating beam assembly, thereby improving the reliability of detection of the input force. Meanwhile, the arrangement of symmetrical distribution can enable the first folding beam 321 and the second folding beam 322 to further reduce the influence of vibration, impact or assembly stress on the tuning fork vibrating beam assembly, improve the stability and durability of the system,
The boss butt-joint parts, the first folding beam 321 and the second folding beam 322 are symmetrically distributed by taking the tuning fork vibration beam assembly as a central line. Referring to fig. 6, preferably, 2 boss-interfacing parts are disposed on a center vertical line of the tuning fork beam assembly, in which case the first folding beam 321 and the second folding beam 322 have the same length. Of course, 2 boss abutment members may be provided at positions distant from the center vertical line of the tuning fork vibrating beam assembly, that is, at positions close to one end or the other end of the tuning fork vibrating beam assembly, in which case the lengths of the first folding beam 321 and the second folding beam 322 are different.
At least one of the first folding beam 321 and the second folding beam 322 has an included angle of 140 degrees or more and 160 degrees or less with the boss abutting part. Preferably, the included angle θ between the first folding beam 321 and the second folding beam 322 and the abutment member of the boss is 150 degrees, which can improve the structural stability of the tuning fork assembly 300. Referring to fig. 7, the tuning fork vibrating beam assembly has a length greater than that of the boss 210, and the included angles between the first folded beam 321 and the second folded beam 322 and the boss interfacing part are 150 degrees, so that when the input force drives the boss 210 to move away from or approach each other, the boss 210 can stably apply compressive stress and tensile stress to the tuning fork vibrating beam assembly through the first folded beam 321 and the second folded beam 322, thereby ensuring stability of pressure detection of the resonant pressure sensor.
The included angle is not limited to 150 degrees, but may be smaller than 150 degrees, or larger than 150 degrees. The included angles between the first folding beam 321 and the second folding beam 322 and the boss butt joint part can be the same, and at this time, the first folding beam 321, the second folding beam 322 and the boss butt joint part are symmetrically distributed by taking the tuning fork vibration beam assembly as a central line. Of course, the included angles between the first folding beam 321 and the second folding beam 322 and the boss butt-joint part may also be different, for example: the first folding beam 321 forms a first included angle with the boss butt joint part, the second folding beam 322 forms a second included angle with the boss butt joint part, the first included angle can be larger than the second included angle, the first included angle can also be smaller than the second included angle, and the size of the first included angle and the second included angle is selected according to actual demands. The angle ranges of the first included angle and the second included angle are 140 degrees or more and 160 degrees or less.
The resonant tuning fork assembly 300 further includes a temperature measuring tuning fork 340, the temperature measuring tuning fork 340 being coupled to the boss mating member, the temperature measuring tuning fork 340 being configured to detect the temperature of the tuning fork vibrating beam assembly. The resonant frequency of the temperature measuring tuning fork 340 can be changed along with the temperature change, and the detection of the temperature of the tuning fork vibrating beam assembly can be realized by detecting the frequency of the tuning fork vibration, so that the temperature compensation of the tuning fork vibrating beam assembly is realized, and the measurement accuracy of the tuning fork vibrating beam assembly under different temperature conditions is improved.
In this embodiment, the temperature measuring tuning fork 340, the boss interfacing part and the tuning fork vibrating beam assembly are integrally formed. For the temperature measurement tuning fork 340 of separation, namely set up separately for temperature measurement tuning fork 340 and resonance tuning fork subassembly 300, integrated into one piece structure can reduce thermal resistance, and the resistance of heat transfer promptly, not only can improve the heat transfer to temperature measurement tuning fork 340 of tuning fork vibration beam subassembly and need the time, temperature measurement tuning fork 340's temperature measurement efficiency is high, sensitivity is good, can also reduce the loss of heat in the transmission process, temperature measurement tuning fork 340 can accurately reflect the core temperature of resonance tuning fork subassembly 300 (can understand the temperature of tuning fork vibration beam subassembly too) to improve the detection precision of temperature measurement tuning fork 340. Meanwhile, the strength and stability of the integral structure can be improved, looseness or deformation is difficult to occur between the structures, stability of the structure of the resonant pressure sensor can be ensured under different working conditions, and therefore accuracy of temperature measurement is improved.
In some embodiments, referring to fig. 6 and 7, the resonant tuning fork assembly 300 further includes a weighted tuning fork 350, the weighted tuning fork 350 being coupled to the temperature measuring tuning fork 340 on an opposite side of the boss interface. It will be appreciated in conjunction with FIG. 5 that the temperature measuring tuning fork 340 and the tuning fork 350 exhibit a symmetrical arrangement, and that the placement of the tuning fork 350 can improve the symmetry of the resonant tuning fork assembly 300, thereby helping to reduce the effects of assembly stresses on the resonant tuning fork assembly 300.
Of course, it is preferred that when the resonant tuning fork assembly 300 further includes a weighted tuning fork 350, the temperature measuring tuning fork 340, the boss interfacing part and the tuning fork vibrating beam assembly are integrally formed.
Wherein the resonant tuning fork assembly 300 is one of quartz, silicon, ceramic, silicon carbide. Preferably, the resonant tuning fork assembly 300 is of quartz material, i.e., the resonant tuning fork assembly 300 is a quartz resonant tuning fork assembly 300. At this time, the thermal expansion coefficients of the respective parts of the tuning fork assembly 300 are identical, that is, the temperature measuring tuning fork 340, the balance weight tuning fork 350, the first folding beam 321, the second folding beam 322, the boss interfacing part and the tuning fork vibrating beam assembly are identical, so that it is further ensured that the temperature measuring tuning fork 340 can accurately reflect the temperature of the tuning fork vibrating beam assembly. Of course, the resonant tuning fork assembly 300 may also be a silicon resonant tuning fork assembly 300, a ceramic resonant tuning fork assembly 300, or a silicon carbide resonant tuning fork assembly 300, and the materials of the resonant tuning fork assembly 300 may be set according to actual requirements, which is not limited herein.
Referring to fig. 6, the tuning fork vibrating beam assembly includes a plurality of tuning fork vibrating beams 311 arranged side by side, one end of the plurality of tuning fork vibrating beams 311 is connected with a first tuning fork junction block 312, and the other end of the plurality of tuning fork vibrating beams 311 is connected with a second tuning fork junction block 313. In this embodiment, the first tuning fork node block 312 and the second tuning fork node block 313 provide the connection nodes for the plurality of tuning fork vibrating beams 311, so that the cooperativity and consistency of the operation of the plurality of tuning forks can be improved, and the deformation degree of the plurality of tuning forks when the plurality of tuning forks are subjected to tensile stress or compressive stress can be improved, thereby ensuring the accuracy of measurement. Meanwhile, a plurality of tuning fork vibration beams 311 are arranged, when one tuning fork vibration beam 311 fails due to a certain reason, the other tuning fork vibration beams 311 can still work normally, so that the resonance pressure sensor can work normally.
The tuning fork vibration beams 311 are provided with an even number, for example, two, four, six and the like tuning fork vibration beams 311 can be provided. Preferably, two tuning fork vibration beams 311 (as shown in fig. 5) are provided, and an even number of tuning fork vibration beams 311 can suppress a common mode error and improve the detection accuracy of the tuning fork vibration beams 311. Of course, an odd number of tuning fork beams 311 may be provided, for example, three tuning fork beams 311, five tuning fork beams 311, etc.
In other embodiments, the tuning fork oscillating beam 311 may be provided with one tuning fork oscillating beam, and no tuning fork junction block is provided. The number of tuning fork beams 311 can be set according to practical requirements, and is not limited herein.
In some embodiments, the first tuning fork node block 312 is connected to a first folded beam 321 and the second tuning fork node block 313 is connected to a second folded beam 322. In this embodiment, the first folding beam 321 and the second folding beam 322 can realize absorption of primary stress and isolation of vibration; when stress or vibration is transferred to the first and second tuning fork joint blocks 312 and 313, the first and second tuning fork joint blocks 312 and 313 can absorb and isolate them again. The first folding beam 321, the second folding beam 322, the first tuning fork node block 312 and the second tuning fork node block 313 are mutually matched, so that secondary isolation can be realized, and the influence of external vibration, impact or stress on the tuning fork vibrating beam 311 is effectively reduced.
In some embodiments, referring to fig. 6, a first tuning fork node block 312 is connected to a first folding beam node block 316 by a first tuning fork stress isolation beam 314, a second tuning fork node block 313 is connected to a second folding beam node block 317 by a second tuning fork stress isolation beam 315, the first folding beam node block 316 is connected to a first folding beam 321, and the second folding beam node block 317 is connected to a second folding beam 322.
In this embodiment, first, the first folding beam 321 and the second folding beam 322 can realize the absorption of primary stress and the isolation of vibration; secondly, when stress or vibration is transferred to the first and second folding beam junction blocks 316 and 317, the first and second folding beam junction blocks 316 and 317 can absorb and isolate the stress or vibration secondarily; then, the stress or vibration is transferred to the first tuning fork stress isolation beam 314 and the second tuning fork stress isolation beam 315, which are absorbed and isolated three times by the first tuning fork stress isolation beam 314 and the second tuning fork stress isolation beam 315; finally, when stress or vibration is transferred to the first tuning fork junction block 312 and the second tuning fork junction block 313, the first tuning fork junction block 312 and the second tuning fork junction block 313 can again absorb and isolate them four times. In this embodiment, multistage absorption and isolation can be achieved for external vibration, impact or stress, and the influence of external vibration, impact or stress on the tuning fork vibrating beam 311 can be significantly reduced.
The present embodiment provides a resonant tuning fork assembly 300 comprising a tuning fork vibrating beam assembly and a temperature measuring tuning fork 340. The tuning fork vibrating beam assembly is used for being connected with a first external circuit, and the frequency of the tuning fork vibrating beam assembly is detected through the first external circuit, so that the detection of input force is realized. The temperature measuring tuning fork 340 is used for connecting a second external circuit, and the frequency of the temperature measuring tuning fork 340 is detected through the second external circuit, so that the temperature measurement of the tuning fork vibrating beam assembly is realized, the accuracy of temperature compensation is improved, and the detection accuracy of the resonance pressure sensor is further improved.
Next, the connection of the tuning fork assembly and the first external circuit, and the connection of the temperature measuring tuning fork 340 and the second external circuit will be described.
Referring to fig. 6, the boss interfacing part includes a first boss interfacing part 331 and a second boss interfacing part 332, the first boss interfacing part 331 is provided with a first pressure measuring excitation pad 3311, and the second boss interfacing part 332 is provided with a first temperature measuring excitation pad 3321.
The surface of the resonant tuning fork assembly 300 is provided with a first excitation electrode 301, the first excitation electrode 301 is connected with a first pressure-measuring excitation pad 3311, the first pressure-measuring excitation pad 3311 is connected with a second pressure-measuring excitation pad 220 through a lead 333, the second pressure-measuring excitation pad 220 is connected with the pressure sensing layer 200, and the second pressure-measuring excitation pad 220 is used for being connected with a first external circuit. Referring to fig. 6, a first boss abutting part 331 is disposed on the right side of the tuning fork beam assembly, and two first pressure measuring excitation pads 3311 are disposed on the first boss abutting part 331. The surface of the tuning fork vibration beam assembly, the surface of the first folding beam 321 and the surface of the second folding beam 322 on the right side of the tuning fork vibration beam assembly are respectively provided with a first excitation electrode 301 so as to realize the connection of the excitation electrodes on the surface of the tuning fork vibration beam assembly and the first pressure measuring excitation pad 3311. The first pressure measuring excitation pad 3311 is connected to the second pressure measuring excitation pad 220 through a wire 333, the second pressure measuring excitation pad 220 is connected to the pressure sensitive layer 200, the second pressure measuring excitation pad 220 is used for being connected to a first external circuit, and the frequency of the tuning fork vibration beam assembly is detected through the first external circuit.
In fig. 6, the black rectangular filling line is schematically indicated as the first excitation electrode 301, and the filling lines of the first folded beam 321 and the second folded beam 322 on the right side of the tuning fork vibrating beam assembly are different from the filling lines of the first folded beam 321 and the second folded beam 322 on the left side of the tuning fork vibrating beam assembly, i.e., the first excitation electrode 301 is disposed on the right side, and the first excitation electrode 301 is not disposed on the left side. It may also be understood that the first folded beam 321 and the second folded beam 322 on the sides of the first boss butt-joint part 331 are provided with the first excitation electrode 301, so as to realize connection of the excitation electrode on the surface of the tuning fork vibration beam assembly and the first pressure measuring excitation pad 3311.
In some embodiments, referring to fig. 4, the length of the capping layer 100 is less than the length of the pressure sensitive layer 200, the second pressure sensitive excitation pad 220 is electrically connected to the third pressure sensitive excitation pad 230, the second pressure sensitive excitation pad 220 is disposed within the vacuum chamber 110, the third pressure sensitive excitation pad 230 is connected to the pressure sensitive layer 200, the third pressure sensitive excitation pad 230 is located outside the vacuum chamber 110, and the third pressure sensitive excitation pad 230 is connected to the first external circuit.
The third piezometric vibration pads 230 are provided in plurality in the pressure sensitive layer 200, and the plurality of third piezometric vibration pads 230 are electrically connected to each other. Referring to fig. 6, when two first pressure measuring excitation pads 3311 are provided, two second pressure measuring excitation pads 220 are correspondingly provided, two third pressure measuring excitation pads 230 are correspondingly provided, and the two third pressure measuring excitation pads 230 are connected to the first external circuit. The third piezometric excitation pads 230 are provided with four third piezometric excitation pads 230, two of which are connected to the second piezometric excitation pads 220, and two third piezometric excitation pads 230 are respectively connected to one third piezometric excitation pad 230, and also the third piezometric excitation pads 230 at the uppermost side and the lowermost side of fig. 6, and this third piezometric excitation pad 230 can be used for testing various performances of the resonant tuning fork assembly 300. The number of the third pressure measuring excitation pads 230 may be set according to actual requirements, and is not limited herein.
The surface of the temperature measuring tuning fork 340 is provided with a second excitation electrode 341, the second excitation electrode 341 is connected with a first temperature measuring excitation pad 3321, the first temperature measuring excitation pad 3321 is connected with a second temperature measuring excitation pad 240 through a lead 333, the second temperature measuring excitation pad 240 is connected with the pressure sensing layer 200, and the second temperature measuring excitation pad 240 is used for being connected with a second external circuit.
In some embodiments, referring to fig. 4 and 6, the length of the sealing cap layer 100 is smaller than the length of the pressure sensing layer 200, the second temperature-measuring excitation pad 240 is connected to the third temperature-measuring excitation pad 250, the second temperature-measuring excitation pad 240 is disposed in the vacuum chamber 110, the third temperature-measuring excitation pad 250 is connected to the pressure sensing layer 200, and the third temperature-measuring excitation pad 250 is located outside the vacuum chamber 110.
The first temperature-measuring excitation pad 3321, the second temperature-measuring excitation pad 240, and the third temperature-measuring excitation pad 250 are the same as the first pressure-measuring excitation pad 3311, the second pressure-measuring excitation pad 220, and the third pressure-measuring excitation pad 230 in the above embodiments, and specific reference is made to the above description, and no limitation is made herein.
In this embodiment, the first pressure measurement excitation pad 3311 is disposed on the first boss 210 component, the first temperature measurement excitation pad 3321 is disposed on the second boss 210 component, and the first pressure measurement excitation pad 3311 and the first temperature measurement excitation pad 3321 are disposed on different boss 210 components, which is helpful for isolating the test circuit of the temperature measurement tuning fork 340 and the tuning fork vibration beam assembly, and can reduce errors caused by mutual interference of the temperature measurement tuning fork 340 and the tuning fork vibration beam assembly, and improve reliability of the resonant pressure sensor.
Referring to fig. 4, the resonant pressure sensor according to the embodiment of the present invention further includes a guide layer 400, the guide layer 400 and the sealing cap layer 100 are respectively located at two sides of the pressure sensing layer 200, a pressure sensing chamber 410 is formed between the pressure sensing layer 200 and the guide layer 400, the guide layer 400 is provided with a guide channel 420 communicating with the pressure sensing chamber 410, and the guide channel 420 is used for introducing a fluid to be measured into the pressure sensing chamber 410, so that the fluid to be measured applies an input force to the pressure sensing layer 200. In this embodiment, the guide layer 400 and the sealing cap layer 100 are respectively located at two sides of the pressure sensing layer 200, so as to protect the pressure sensing layer 200, thereby prolonging the service life of the pressure sensing layer 200.
The fluid to be measured can be gas, liquid or a gas-liquid mixture.
In this embodiment, the side of the guide layer 400 remote from the pressure sensitive layer 200 is used for bonding to a package or a base. When external vibration or impact is transmitted to one side of the guide layer 400 away from the pressure sensing layer 200, the guide layer 400 can absorb a part of stress and energy generated by the vibration or impact, reduce the influence of the vibration or impact on the pressure sensing layer 200, and improve the detection sensitivity.
Wherein assembly stresses are created when the guide layer 400 is bonded to the package or base. When the material of the package or the material of the base is different from that of the guide layer 400, that is, the thermal expansion coefficient is different, stress strain is easily generated in the pressure sensing layer 200, and thus frequency drift of the tuning fork vibrating beam assembly is caused (the frequency drift of the vibrating beam refers to the change of the resonant frequency of the tuning fork vibrating beam 311 with time or the environmental condition, and such drift may be caused by various factors including temperature change, stress, vibration, impact, etc.). The arrangement of the guide layer 400 can effectively absorb assembly stress and thermal stress, the isolation effect of the guide layer 400 is good, and the detection effect of the tuning fork vibration beam assembly can be guaranteed.
Referring to fig. 4, a first isolation groove 430 is provided at a side of the guide layer 400 away from the pressure sensitive layer 200, and the first isolation groove 430 can achieve a first level of blocking of vibration, impact, assembly stress, thermal stress, or the like at a side away from the pressure sensitive layer 200, thereby improving an isolation effect of the guide layer 400.
Referring to fig. 4, a second isolation groove 440 is provided at a side of the guide layer 400 adjacent to the pressure sensing layer 200, and the second isolation groove 440 can block vibration, impact, assembly stress, thermal stress, or the like at a side adjacent to the pressure sensing layer 200, thereby improving an isolation effect of the guide layer 400.
Of course, in some embodiments, the guide layer 400 is provided with a first isolation groove 430 and a second isolation groove 440, the first isolation groove 430 is disposed at a side of the guide layer 400 away from the pressure sensitive layer 200, and the second isolation groove 440 is disposed at a side close to the pressure sensitive layer 200. The first isolation trench 430 and the second isolation trench 440 cooperate with each other to achieve a secondary isolation barrier effect. Taking the example of blocking thermal stress, the first isolation groove 430 can perform a first level of blocking of thermal stress generated by the external pipe shell; the second isolation groove 440 can provide a second level of resistance to thermal stress on the external envelope. Under severe mechanical environments such as vibration and impact, the first isolation groove 430 and the second isolation groove 440 can effectively weaken the influence of the vibration and impact on the pressure sensing layer 200, and the influence of external vibration or impact on the pressure sensing layer 200 and the tuning fork assembly 300 can be effectively reduced.
The first isolation groove 430 may be provided in plurality to enhance the stress isolation effect. Of course, a plurality of second isolation grooves 440 may be provided. The first isolation groove 430 and the second isolation groove 440 may be offset, so that stress isolation can be achieved at different positions; the first isolation groove 430 and the second isolation groove 440 may also be coaxially disposed to achieve stress isolation on the same axis. When the first isolation groove 430 is provided in plurality and the second isolation groove 440 is provided in plurality, the first isolation groove 430 and the second isolation groove 440 may be both coaxially provided, may be both provided in offset, or may be provided with a part of the first isolation groove 430 and the second isolation groove 440 coaxially provided, and another part of the first isolation groove 430 and the second isolation groove 440 may be provided in offset. The arrangement of the first isolation groove 430 and the second isolation groove 440 may be set according to actual requirements, which is not limited herein.
Preferably, referring to fig. 11, the first isolation groove 430 is an annular groove, the second isolation groove 440 is also an annular groove, and the first isolation groove 430 and the second isolation groove 440 are surrounded on the sidewall of the guide layer 400, and the annular groove can effectively increase the areas of the first isolation groove 430 and the second isolation groove 440, thereby increasing the isolation effect.
An embodiment of the second aspect of the present invention provides a method for manufacturing a resonant pressure sensor, the method comprising the steps of:
s1, forming a boss 210 on the pressure sensing layer 200; wherein, the forming of the boss 210 may be forming the boss 210 by etching the pressure sensitive layer 200, and the etching may be wet chemical etching, dry etching, laser etching, etc.;
s2, arranging the resonant tuning fork assembly 300 on the pressure sensing layer 200, wherein the resonant tuning fork assembly 300 is connected with the boss 210;
in this step, the resonant tuning fork assembly 300 is disposed on the pressure sensing layer 200, and may be a first folded beam 321 and a second folded beam 322 coupled to the boss 210.
When the resonating tuning fork assembly 300 includes a boss interfacing part, the boss interfacing part may be connected to the boss 210 through the first glass paste 510, and the boss interfacing part and the boss 210 may be connected by sintering the first glass paste 510 at a first preset temperature for a first preset period of time.
When the sensing layer is provided with the boss 210, but the first groove 270 is not provided, the first preset temperature may be 415 to 465 degrees, and the first preset time period may be 10 to 20 minutes. Preferably, the first preset temperature is 440 degrees and the first preset time period is 15 minutes.
When the sensing layer is provided with the boss 210 and the first groove 270, the first preset temperature may be 365-415 degrees, and the first preset time period may be 10-20 minutes. Preferably, the first preset temperature is 390 degrees and the first preset time period is 15 minutes.
And S3, arranging the sealing cap layer 100 on the pressure sensing layer 200, wherein the sealing cap layer 100 is connected with the pressure sensing layer 200.
In this step, the sealing cap layer 100 is connected to the pressure sensing layer 200 through the second glass paste 520, and the second glass paste 520 is sintered for a second preset time period at a second preset temperature, thereby realizing the connection of the sealing cap layer 100 and the pressure sensing layer 200. Wherein the second preset temperature is less than the first preset temperature.
When the sensing layer is provided with the boss 210, but the first groove 270 is not provided, the second preset temperature may be 405 to 455 degrees, and the second preset time period may be 10 to 20 minutes. Preferably, the second preset temperature is 430 degrees and the second preset time period is 15 minutes.
When the sensing layer is provided with the boss 210 and the first groove 270, the second preset temperature may be 355-405 degrees, and the second preset time period may be 10-20 minutes. Preferably, the second preset temperature is 380 degrees and the second preset time period is 15 minutes.
The method for manufacturing the resonant pressure sensor provided by the embodiment of the second aspect of the invention further comprises the following steps: the pressure sensitive layer 200 is disposed on the guide layer 400.
In this step, the pressure sensitive layer 200 is sintered and connected to the guide layer 400 by the third glass paste 530, and the third glass paste 530 is sintered for a third preset time period at a third preset temperature.
When the sensing layer is provided with the boss 210, but the first groove 270 is not provided, the third preset temperature may be 425-475 degrees, and the third preset time period may be 10-20 minutes. Preferably, the third preset temperature is 450 degrees and the third preset time period is 15 minutes.
When the sensing layer is provided with the boss 210 and the first groove 270, the third preset temperature may be 375-425 degrees, and the third preset time period may be 10-20 minutes. Preferably, the third preset temperature is 400 degrees and the third preset time period is 15 minutes.
Next, a resonant pressure sensor and a method of manufacturing the same provided by the embodiment of the invention will be described.
(1) Adopting a full quartz sensitive structure scheme; the pressure sensing layer 200, the resonance tuning fork assembly 300, the guide layer 400, the temperature measuring tuning fork 340 and the sealing cap layer 100 are all made of quartz crystal materials, so that the matching property of the thermal expansion coefficients of the materials is improved, the problem of temperature drift caused by mismatching of the thermal expansion coefficients of the materials is solved, the pressure sensing assembly adopts a QMES (quality control message service) process to conduct sheet flow processing, and a traditional processing method for processing single part is replaced, so that the processing efficiency is improved.
(2) Adopting a glass paste sealing structure scheme with a getter; the glass paste matched with the thermal expansion coefficient of the quartz crystal is selected to realize vacuum sealing sintering of the quartz component (sintering of the resonant tuning fork component 300 and the pressure sensitive layer 200, sintering of the sealing cap layer 100 and the pressure sensitive layer 200, and sintering of the pressure sensitive layer 200 and the guide layer 400), respectively form the vacuum chamber 110 and the pressure sensitive chamber 410, and effectively protect the electrodes (the first excitation electrode 301 and the second excitation electrode 341). The preparation of the thin film getter layer 120 is realized at the bottom of the cavity 130 of the sealing cap layer 100 by using a magnetron sputtering technology and a shielding plate technology, and the activation of the getter layer 120 is realized by using an infrared irradiation heating technology, so that the long-term maintenance of high vacuum degree is achieved, and the quartz harmonic oscillator (namely the resonant tuning fork assembly 300) is ensured to have a higher quality factor.
(3) A tuning fork vibrating beam 311 scheme with a temperature measuring tuning fork 340 and a lever multiplication structure; on the basis of the tuning fork vibrating beam assembly, a temperature measuring tuning fork 340 and a lever multiplication structure are integrated, and integrated processing is realized. The axial force of the tuning fork vibrating beam 311 is amplified by utilizing the lever multiplication structure, the force frequency coefficient of the tuning fork vibrating beam 311 is improved, the sensitivity of the resonant pressure sensor is improved as a whole, the influence of external thermal stress on the tuning fork vibrating beam 311 is effectively isolated, and the problem of stress isolation under the condition of high sensitivity is solved. The integrated temperature measuring tuning fork 340 can accurately reflect the core temperature of the resonant tuning fork assembly 300 (i.e., the temperature of the tuning fork vibrating beam 311), improve the temperature compensation effect, and avoid the error caused by the need of secondary adhesion of the temperature measuring tuning fork 340 due to the separate arrangement of the temperature measuring tuning fork 340 and the tuning fork vibrating beam assembly.
(4) A structure of the pressure sensitive layer 200 with the first grooves 270 and the bosses 210 is adopted. Firstly, the structure of the pressure sensing layer 200 with the first groove 270 and the boss 210 can convert the pressure sensing deformation of the pressure sensing layer 200 from the traditional tension-compression deformation into bending deformation, and improve the sensitivity of the pressure sensing layer 200; secondly, in the assembly process, the overstocked pressure sensing layer 200 may have distortion due to the assembly stress, and the pressure sensing layer 200 may effectively absorb the assembly stress; third, when the sensitive structure is tested at high and low temperatures, the thermal stress existing in the sensitive structure can cause the pressure sensing layer 200 to distort, and the first groove 270 and the boss 210 can effectively absorb the thermal stress; fourth, the boss 210 structure can increase the deformation amount of the pressure sensitive film, thereby improving the sensitivity.
(5) Adopting an internal and external two-stage stress isolation scheme; an inner and outer two-stage stressed isolation groove (i.e., a first isolation groove 430 and a second isolation groove 440) is designed on the guide layer 400. After wafer-level bonding is adopted, effective isolation of assembly stress, thermal stress and vibration impact force is realized. When the resonant pressure sensor is bonded to the T0 tube or LCC ceramic tube base, assembly stresses can result due to mismatch in the coefficients of thermal expansion (also known as differential thermal expansion) of the tube material and the quartz material. By designing a two-stage stress isolation trench on the guiding layer 400, effective isolation of assembly stress is achieved. Under high and low temperature conditions, the mismatch of thermal expansion coefficients between the tube shell and the resonant pressure sensor easily causes thermal stress to be transferred to the resonant pressure sensor, and causes stress strain to be generated in the pressure sensing layer 200, thereby causing frequency drift of the tuning fork resonant beam 311. The design of the external isolation groove (i.e., the first isolation groove 430) can perform a first level of blocking of the thermal stress generated by the external pipe shell; the internal stress isolation groove (i.e., the second isolation groove 440) is designed at the bonding position of the guide layer 400 and the pressure sensing layer 200, so that the thermal stress of the external pipe shell can be blocked for the second stage. Under severe mechanical environments such as vibration and impact, the isolation groove can effectively weaken the influence of vibration and impact on the resonant pressure sensor, and the influence of external vibration or impact on the pressure sensing layer 200 and the resonant tuning fork assembly 300 is minimized.
The manufacturing method of the resonant pressure sensor provided by the embodiment of the invention adopts an all-quartz vibration beam structure with temperature compensation, the whole structure is shown in fig. 4, and the whole sensitive structure comprises four layers of structures: a guiding layer 400, a pressure sensing layer 200, a vibration beam layer and a sealing cap layer 100.
First, the pressure sensing layer 200 and the guiding layer 400 are bonded at a wafer level through glass paste (i.e., third glass paste 530), the sintering temperature (third preset temperature) is 425-475 degrees, and the holding time (third preset duration) is 10-20 minutes. Wherein, preferably, the bonding temperature is 450 ℃, and the heat preservation time is 15 minutes;
secondly, the resonant tuning fork assembly 300 is arranged on the two layers of combined sheets (the pressure sensing layer 200 and the guide layer 400) through a visual alignment patch technology by using glass paste (namely, the first glass paste 510), so that the patch and sintering of the part on the wafer are realized, the sintering temperature (the first preset temperature) is 415-465 ℃, and the heat preservation time (the first preset duration) is 10-20 minutes. Wherein, preferably, the sintering temperature is 440 ℃, the heat preservation time is 15 minutes, and the vibration beam electrode and the pressure sensing layer 200 electrode realize electrical traction through the wafer level Jin Sibang;
the visual alignment patch technique refers to, among other things, capturing an image of the resonating tuning fork assembly 300 and the target location (which may be understood as the location of the boss 210) using a camera and image processing software, and processing the image to determine the location, orientation, and other relevant characteristics of the resonating tuning fork assembly 300. Based on the image processing results, the resonant tuning fork assembly 300 is precisely aligned to the target location. When the resonant tuning fork assembly 300 is aligned to the target location, the resonant tuning fork assembly 300 is adhered to the boss 210 by the first glass paste 510.
Finally, the capping layer 100 and the three-layer combination sheet (the resonant tuning fork assembly 300, the pressure sensitive layer 200 and the guiding layer 400) realize wafer-level vacuum bonding with activation of the getter layer 120, the bonding temperature (second preset temperature) is 405-455 degrees, and the holding time (second preset duration) is 15 minutes. Wherein, preferably, the bonding temperature is 430 ℃ and the heat preservation time is 15 minutes.
Wherein activation of the getter layer 120 is performed prior to sintering the cap layer 100 and the tri-layer composite sheet. Activation of the getter layer 120 is achieved by infrared radiation heating techniques. Preferably, the getter activation temperature is 500 degrees and the activation time is 15 minutes. The getter layer 120 releases a large amount of gas when activated, which is required before the cap layer 100 and the tri-layer composite sheet are sintered, so as to avoid the influence of the gas released from the getter layer 120 on the tuning fork assembly 300.
As shown in fig. 6, the resonant tuning fork assembly 300 with the cap layer 100 removed includes a tuning fork vibrating beam assembly and a temperature measuring tuning fork 340, and two electrodes (i.e., the second excitation electrode 341) of the temperature measuring tuning fork 340 are bonded by gold wires (i.e., the wires 333) to lead out the electrodes on the pressure sensing layer 200. The electrode (i.e. the first excitation electrode 301) of the tuning fork vibrating beam assembly is led out on the pressure sensing layer 200 through gold wire bonding, and the bonding gold wire diameter is 10-25 um.
The structure with the sealing cap layer 100, the vibration beam layer and the Jin Sibang alignment removed is shown in fig. 8, and includes a pressure sensing layer 200 with a second groove 280 (wherein the pressure sensing layer 200 forms the second groove 280 when the boss 210 is formed by etching), an excitation pad on the surface of the pressure sensing layer 200, an electrode lead 260, a quartz boss 210 and a bonding glass paste ring (the glass paste ring is the second glass paste 520). The surface functional pad size of the pressure sensing layer 200 is 250um by 250um, the routing width of the electrode lead 260 is 50um, and the bonding paste ring width is 1mm.
The capping layer 100 was a 3 inch diameter quartz wafer cut with z 0. As shown in fig. 13, the cavity 130 is processed by wet etching, a hard shielding plate process and a magnetron sputtering technology are adopted to sputter a non-evaporable metal film getter at the bottom of the cavity 130, and the main component of the target is titanium-zirconium alloy. The specific dimensions of the structure of the capping layer 100 are shown in table 1, in conjunction with fig. 4 and 13.
TABLE 1 sealing cap layer size parameter (Unit: um)
| h1 | d1 | h2 | d2 | h3 | d3 | e1 | e2 | e3 |
| 9500 | 9500 | 7500 | 7500 | 1600 | 8000 | 1500 | 500 | 1 |
The beam layer (i.e., the resonating tuning fork assembly) uses a 3 inch diameter quartz wafer with a z0 cut. As shown in fig. 7, the quartz vibration beam with the temperature measuring tuning fork 340 and the lever multiplication structure comprises eight parts: tuning fork oscillating beam 311, tuning fork nodal blocks (first tuning fork nodal block 312 and second tuning fork nodal block 313), tuning fork stress isolation beams (first tuning fork stress isolation beam 314 and second tuning fork stress isolation beam 315), folding beam nodal blocks (first folding beam nodal block 316 and second folding beam nodal block 317), folding beams (first folding beam 321 and second folding beam 322), boss interfacing components (first boss interfacing component 331 and second boss interfacing component 332), temperature measuring tuning fork 340 and weighted tuning fork 350.
Each pair of tuning fork vibrating beams 311 work through horizontal differential mode resonance of two single beams, the two single beams are in coupling connection through tuning fork nodes, the tuning fork nodes are connected with a single tuning fork stress isolation beam, the effect of stress isolation is achieved, and four folding beams and the tuning fork vibrating beams 311 form a diamond-shaped combined beam structure in a node area.
When the pressure sensing layer 200 senses pressure input in the normal direction, the deformation of the pressure sensing layer 200 causes the relative position between the two bosses 210 to change, so that the relative position between the boss butt-joint parts is driven to change, and the folding beam generates tension-compression deformation.
When the phase positions of the two boss butt joint parts are increased, the axial compressive stress of the tuning fork vibration beam 311 is increased through the four folding beams, and the resonance frequency of the tuning fork vibration beam 311 is reduced. When the relative positions of the two boss abutting parts are reduced, the axial tensile stress of the tuning fork vibrating beam 311 is reduced by the four folding beams, and the tuning fork resonant frequency is increased. The recommended resonance frequency of the tuning fork beam 311 is 34 kHz-36 kHz. When the pressure sensing layer 200 only comprises the boss 210, the recommended quality factor Q is 8000-10000; when the pressure sensitive layer 200 includes the boss 210 and the first groove 270, the recommended quality factor Q is 12000 to 19000.
The integrated temperature measuring tuning fork 340 adopts a tuning fork-shaped structure with a single end fixed, two tines adopt a plane differential mode as a working mode, the recommended resonant frequency is 120 kHz-130 kHz, and the temperature model of the temperature measuring tuning fork 340 under the plane differential mode is as follows:
here, Δf=f—f0; Δt=t-T0; fand f0 are the resonant frequencies of the thermometric tuning fork 340 at temperatures T and T0 (t0=25℃), respectively. α0, α1, α2, and α3 are each 0 to 3-order temperature coefficients. The quartz crystal cut by Z0 is adopted by the temperature measuring tuning fork 340, so that alpha 2 and alpha 3 are close to zero, the first-order temperature coefficient alpha 1 is 35-45 ppm/DEG C, and the temperature measuring range is as follows: the temperature measurement precision can reach 0.02 ℃ at-80 ℃ to 230 ℃.
To improve the symmetry of the resonant pressure sensor, a weighted tuning fork 350 is added. The weight tuning fork 350 has the same structural dimensions as the temperature measuring tuning fork 340, and therefore, the vibrating beam has one temperature measuring tuning fork 340 and one weight tuning fork 350. The thickness of the temperature measuring tuning fork 340, the balance tuning fork 350, the folded beam and the vibrating beam is h0, and preferably the folded beam forms an angle θ=60 degrees with the horizontal, and the recommended structural dimensions of the resonant tuning fork assembly are shown in table 2 in conjunction with fig. 7.
TABLE 2 Quartz vibration beam dimension parameters with temperature measurement tuning fork (Unit: um)
| Structural parameters | L1 | L2 | L3 | L4 | L5 | L6 | L7 | L8 | L9 | L10 | W0 | h0 |
| Vibration beam | 2000 | 300 | 350 | 500 | 35 | 600 | 600 | 100 | 100 | 400 | 50 | 80 |
| Structural parameters | W1 | W2 | W3 | W4 | W5 | W6 | W7 | W8 | W9 | W10 | W11 | W12 |
| Vibration beam | 30 | 500 | 60 | 800 | 60 | 500 | 1000 | 300 | 500 | 100 | 55 | 55 |
The pressure sensitive layer 200 is a 3 inch diameter quartz wafer cut at z 0. The structure is shown in fig. 8, the thickness of the sheet is 220um to 1920um, and the key structure comprises a pressure sensing layer 200, a quartz boss 210 and a gold-plated electrode layer 290 (comprising an excitation pad and an electrode lead 333 connected with the excitation pad). When the pressure sensitive layer 200 includes the boss 210 and the first groove 270, since the opposite sides of the pressure sensitive film simultaneously start wet etching, the depth of the first groove 270 and the height of the boss 210 are equal. The thickness of the pressure sensing layer 200 is determined by the measuring range of the resonance pressure sensor, the design thickness of the pressure sensing layer 200 is 100 um-1800 um, and the measuring range of the resonance pressure sensor is 100 kPa-50.1 MPa. The height of the quartz boss 210 is 120-240 um, and preferably, the height of the quartz boss 210 is 120um. The quartz boss 210 plays a role of amplifying the strain of the pressure sensing layer 200 here, improving the pressure sensing sensitivity of the pressure sensing layer 200. The gold-plated electrode layer 290 is a base of a magnetron sputtered chromium-based film, which can provide stable connection for the connection of the gold-plated electrode layer 290 and the pressure sensitive layer 200, and then the gold-plated electrode layer is magnetron sputtered.
Referring to fig. 8 and 9, when the pressure sensitive layer 200 is provided with only the boss 210, excluding the first groove 270, the recommended dimensions of the pressure sensitive layer 200 are shown in table 3. Taking the quartz boss 210 with the height of 120um as an example, the thickness of the pressure sensing layer 200 under different measuring ranges and the thickness of the pressure sensing layer 200 at the position of the boss 210 after the boss 210 is formed by etching are shown in table 4.
TABLE 3 size parameters of Quartz pressure sensitive layers (Unit: um)
| h7 | d7 | h8 | d8 | h9 | d9 | h10 | d10 | d11 | d12 | e7 | e8 | e9 |
| 10000 | 10000 | 7000 | 7000 | 600 | 1000 | 600 | 500 | 400 | 1000 | 400 | 0.5 | 100 |
TABLE 4 pressure sensitive layer and pressure sensitive layer thickness parameters (um) at different ranges
| Measuring range | 100kPa | 200kPa | 500kPa | 1.7MPa | 3.6MPa | 50.1MPa |
| Thickness of pressure sensitive layer e7 | 220 | 270 | 370 | 520 | 620 | 1920 |
| Thickness e9 of pressure sensing layer at boss | 100 | 150 | 250 | 400 | 500 | 1800 |
Referring to fig. 8 and 10, when the pressure sensitive layer 200 is provided with the boss 210 and the first groove 270 at the same time, recommended dimensions of the pressure sensitive layer 200 are shown in table 5. Taking the quartz boss 210 with the height of 120um as an example, the thickness of the pressure sensing layer 200 under different measuring ranges and the thickness of the pressure sensing layer 200 at the position of the boss 210 after the boss 210 is formed by etching are shown in table 6.
TABLE 5 size parameters of Quartz pressure sensitive layers (Unit: um)
| h7 | d7 | h8 | d8 | h9 | d9 | h10 | d10 |
| 10000 | 10000 | 7000 | 7000 | 600 | 1000 | 600 | 500 |
| d11 | d12 | e7 | e8 | e9 | e10 | e11 | e12 |
| 400 | 1000 | 400 | 0.5 | 100 | 100 | 1000 | 7000 |
TABLE 6 pressure sensitive layer and pressure sensitive film thickness parameters (um) at different ranges
| Measuring range | 100kPa | 200kPa | 500kPa | 1.7MPa | 3.6MPa | 50.1MPa |
| Thickness of pressure sensitive layer e7 | 220 | 270 | 370 | 520 | 620 | 1920 |
| Lower underlayer thickness e9 | 100 | 150 | 250 | 400 | 500 | 1800 |
| Lower underlayer thickness e10 | 100 | 150 | 250 | 400 | 500 | 1800 |
| Thickness e13 | 100 | 150 | 250 | 400 | 500 | 1800 |
The guide layer 400 is a 3-inch quartz wafer with a z0 cut diameter, the structure is shown in fig. 12, annular stress isolation grooves are processed on the upper and lower surfaces of the guide layer 400 by wet etching, the guide channel 420 is processed by ultrasonic punching technology, and specific dimensions are shown in table 7 in combination with fig. 11 and 12.
TABLE 7 size parameters of quartz gas guide layer (Unit: um)
| h4 | d4 | h5 | d5 | h6 | d6 | e4 | e5 | e6 |
| 10000 | 10000 | 7000 | 7000 | 1600 | 8000 | 500 | 500 | 1200 |
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A resonant pressure sensor, comprising:
sealing the cap layer;
the pressure sensing layer is used for sensing the change of input force, the pressure sensing layer is connected with the sealing cap layer, a vacuum cavity is formed between the sealing cap layer and the pressure sensing layer, the pressure sensing layer is provided with at least two bosses and at least two first grooves, the bosses and the first grooves are arranged in a one-to-one correspondence manner, the bosses are positioned in the vacuum cavity, the first grooves are arranged on one side, far away from the sealing cap layer, of the pressure sensing layer, and the bosses and the first grooves are sequentially arranged along the direction far away from the input force;
and the resonant tuning fork assembly is arranged in the vacuum chamber, at least two bosses are arranged on opposite sides of the resonant tuning fork assembly, the resonant tuning fork assembly is connected with the bosses, and the resonant tuning fork assembly is used for being connected with a first external circuit.
2. The resonant pressure sensor of claim 1, wherein two bosses are provided, two first grooves are provided, two bosses are provided on opposite sides of the input force, and the input direction of the input force is perpendicular to the connecting line direction of the two bosses.
3. The resonant pressure sensor of claim 2, wherein a side of the pressure sensing layer facing the vacuum chamber is formed with a second recess, the boss is disposed in the second recess, and the first recess is spaced apart from the second recess.
4. The resonant pressure sensor of claim 3, wherein a first sidewall of the first groove adjacent to the second groove is parallel to a second sidewall of the second groove adjacent to the first groove, the first sidewall and the second sidewall being at a distance of 100 microns or more and 1800 microns or less.
5. A resonant pressure sensor according to claim 3, wherein the depth of the first recess and the height of the boss are the same and/or the depth of the second recess and the height of the boss are the same.
6. A resonant pressure sensor according to claim 3, wherein the thickness of the pressure sensitive layer is 220 microns or more and 1920 microns or less, and the height of the boss is 120 microns or more and 240 microns or less.
7. The resonant pressure sensor of claim 2, wherein a distance between two of the first grooves is 5000 microns or more and 7000 microns or less, and an open end length of the first grooves is 1000 microns or more and 2000 microns or less.
8. The resonant pressure sensor of any one of claims 1 to 7, wherein the resonant tuning fork assembly comprises a tuning fork vibrating beam assembly, a first folding beam and a second folding beam, one end of the tuning fork vibrating beam assembly is connected to the boss through the first folding beam, the other end of the tuning fork vibrating beam assembly is connected to the boss through the second folding beam, and the first folding beam, the second folding beam and the tuning fork vibrating beam assembly are suspended.
9. The resonant pressure sensor of claim 8, wherein the resonant tuning fork assembly further comprises a boss mating member, at least one of the first folded beam and the second folded beam being coupled to the boss by the boss mating member, the boss being provided in two, the boss mating member being provided in two, the boss and the boss mating member being provided in one-to-one correspondence, the tuning fork vibrating beam assembly being provided between the two boss mating members.
10. A method of manufacturing a resonant pressure sensor according to any one of claims 1 to 9, comprising:
forming the boss on the pressure sensing layer;
disposing the resonant tuning fork assembly on the pressure sensing layer, wherein the resonant tuning fork assembly is coupled to the boss;
And arranging the sealing cap layer on the pressure sensing layer, wherein the sealing cap layer is connected with the pressure sensing layer.
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| CN202311553017.5A CN117686131A (en) | 2023-11-20 | 2023-11-20 | Resonant pressure sensor and method for manufacturing the same |
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