High-precision pressure sensitive structure, sensor and manufacturing method

Abstract

The invention relates to the technical field of capacitive pressure sensors, and provides a high-precision pressure sensitive structure, a sensor and a manufacturing method, and the structure comprises an upper substrate which is provided with a first upper electrode and a detection through hole; the pressure sensing film is provided with a second upper electrode, a first lower electrode and a stress isolation structure, one side of the pressure sensing film is connected with the upper substrate to form a first cavity communicated with the detection through hole, and the second upper electrode and the first upper electrode are both located in the first cavity and are oppositely arranged; the lower substrate is provided with a second lower electrode, the other side of the pressure sensing film is connected with the lower substrate to form a second cavity, and the second lower electrode and the first lower electrode are both located in the second cavity and are oppositely arranged. The stress isolation structure is arranged on the pressure sensing film, so that the stress is absorbed by the stress isolation structure, the deformation of the pressure sensing film caused by the stress is reduced, the problem of zero drift is prevented, and the accuracy of pressure measurement and the stability of long-term use are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitive pressure sensors, and in particular to a high-precision pressure sensitive structure, a sensor and a manufacturing method. Background Art

[0002] A capacitive pressure sensor is a sensor that works based on the principle of capacitance and is used to measure pressure changes. When the pressure changes, it causes the pressure-sensitive membrane to deform, causing the distance between the two electrodes that form the capacitor to change, and then the capacitance value changes. There is a correlation between pressure and capacitance value, and pressure measurement is achieved based on this.

[0003] In the prior art, since assembly stress or packaging stress is inevitable during the assembly and packaging process, for the sensitive pressure-sensitive membrane, the stress transferred to the pressure-sensitive membrane will cause deformation of the pressure-sensitive membrane, thereby causing the problem of zero point drift, affecting the accuracy of pressure measurement and affecting the stability of long-term use. Summary of the invention

[0004] The present invention provides a high-precision pressure sensitive structure, a sensor and a manufacturing method, which are used to solve the defect in the prior art that stress causes deformation of a pressure sensitive film and thus causes zero point drift.

[0005] The present invention provides a high-precision pressure sensitive structure, comprising: An upper substrate is provided with a first upper electrode and a detection through hole; A pressure-sensitive film is provided with a second upper electrode, a first lower electrode and a stress isolation structure, one side of the pressure-sensitive film is connected to the upper substrate to form a first chamber connected to the detection through hole, and the second upper electrode and the first upper electrode are both located in the first chamber and arranged opposite to each other; A lower substrate is provided with a second lower electrode, the other side of the pressure-sensitive film is connected to the lower substrate to form a second chamber, and the second lower electrode and the first lower electrode are both located in the second chamber and are arranged opposite to each other; The stress isolation structure is used to absorb stress to reduce deformation of the pressure-sensitive film caused by the stress.

[0006] According to a high-precision pressure-sensitive structure provided by the present invention, the stress isolation structure includes an annular recessed portion disposed on the pressure-sensitive film, and the annular recessed portion surrounds the second upper electrode or the first lower electrode.

[0007] According to a high-precision pressure-sensitive structure provided by the present invention, two annular recesses are provided, one of the two annular recesses surrounds the second upper electrode, and the other annular recess surrounds the first lower electrode, and the projections of the two annular recesses overlap.

[0008] According to a high-precision pressure-sensitive structure provided by the present invention, a first bonding structure is provided between the upper substrate and the pressure-sensitive film, and the upper substrate is connected to the pressure-sensitive film through the first bonding structure to form the first chamber; A second bonding structure is disposed between the lower substrate and the pressure-sensitive film, and the lower substrate is connected to the pressure-sensitive film through the second bonding structure to form the second chamber.

[0009] According to a high-precision pressure-sensitive structure provided by the present invention, the first bonding structure includes a first glass paste bonding layer, the first glass paste bonding layer is ring-shaped and surrounds the first upper electrode and the second upper electrode, and the first glass paste bonding layer is connected to the upper substrate and the pressure-sensitive film respectively; The second bonding structure includes a second glass paste bonding layer, which is ring-shaped and surrounds the first lower electrode and the second lower electrode, and is connected to the lower substrate and the pressure-sensitive film respectively.

[0010] According to a high-precision pressure-sensitive structure provided by the present invention, the upper substrate is provided with a first limiting convex portion, and the first limiting convex portion is used to abut against the pressure-sensitive film to limit the distance between the first upper electrode and the second upper electrode; The lower substrate is provided with a second limiting protrusion, and the second limiting protrusion is used to abut against the pressure-sensitive film to limit the distance between the first lower electrode and the second lower electrode.

[0011] According to a high-precision pressure-sensitive structure provided by the present invention, the upper substrate is provided with at least two first limiting protrusions, and the first limiting protrusions are evenly arranged around the first glass paste bonding layer; The lower substrate is provided with at least two second limiting protrusions, and the second limiting protrusions are evenly arranged around the second glass paste bonding layer.

[0012] A high-precision pressure-sensitive structure provided according to the present invention also includes a processing chip arranged on the upper substrate, the upper substrate is provided with a first solder pad connected to the first upper electrode, the pressure-sensitive film is provided with a second solder pad respectively connected to the second upper electrode and the first lower electrode, the lower substrate is provided with a third solder pad connected to the second lower electrode, and the processing chip is connected to the first solder pad, the second solder pad and the third solder pad, respectively.

[0013] The present invention also provides a pressure sensor, comprising a sensor body, wherein the sensor body is provided with the above-mentioned high-precision pressure sensitive structure.

[0014] The present invention also provides a method for manufacturing a high-precision pressure sensitive structure, which is applied to the above-mentioned high-precision pressure sensitive structure, comprising: Prepare a screen printing plate, wherein the screen printing plate is provided with a first alignment mark portion and a slurry unit; Prepare an upper substrate sheet and a lower substrate sheet, wherein the upper substrate sheet is provided with a second alignment mark portion, a first upper electrode, and a first pad connected to the first upper electrode, and the lower substrate sheet is provided with a third alignment mark portion, a second lower electrode, and a third pad connected to the second lower electrode; Prepare a pressure-sensitive membrane, wherein the pressure-sensitive membrane is provided with a fourth alignment mark portion, a stress isolation structure, a second upper electrode, a first lower electrode, and a second pad respectively connected to the second upper electrode and the first lower electrode; Using CCD alignment, based on the overlap of the projections of the first alignment mark portion and the second alignment mark portion, printing the paste unit of the screen printing plate onto the upper substrate to form a first glass paste layer, and based on the overlap of the projections of the first alignment mark portion and the third alignment mark portion, printing the paste unit of the screen printing plate onto the lower substrate to form a second glass paste layer; The upper substrate and the lower substrate are heated according to a first preset temperature curve to debind the first glass paste layer and the second glass paste layer, and the first glass paste layer and the second glass paste layer are melted and sintered to form a first sintered glass paste layer and a second sintered glass paste layer; Using an alignment device, adjusting the relative position of the lower base sheet and the pressure-sensitive membrane so that the projections of the third alignment mark portion and the fourth alignment mark portion overlap, and adding glue between the lower base sheet and the pressure-sensitive membrane to pre-fix the lower base sheet and the pressure-sensitive membrane; Using a positioning device, adjusting the relative position of the upper base sheet and the pressure-sensitive membrane so that the projections of the second positioning mark portion and the fourth positioning mark portion overlap, and adding glue between the upper base sheet and the pressure-sensitive membrane to pre-fix the upper base sheet and the pressure-sensitive membrane; The pre-fixed upper substrate, the pressure-sensitive membrane and the lower substrate are clamped and heated according to a second preset temperature curve and a preset pressure curve, so that the first sintered glass paste layer forms a first glass paste bonding layer to bond the upper substrate to the pressure-sensitive membrane, and the second sintered glass paste layer forms a second glass paste bonding layer to bond the lower substrate to the pressure-sensitive membrane, and the pre-fixed glue is carbonized and decomposed; Performing a scribing process on the bonded upper base sheet, the pressure-sensitive film sheet and the lower base sheet to form a bonded upper substrate, a pressure-sensitive film and a lower substrate; The processing chip is fixed on the upper substrate, and the processing chip is respectively connected to the first pad, the second pad and the third pad by gold wire bonding using a bonding device.

[0015] A high-precision pressure-sensitive structure, sensor and manufacturing method provided by the present invention have at least the following beneficial effects: by providing a stress isolation structure on the pressure-sensitive film, the stress generated by the upper substrate, the pressure-sensitive film and the lower substrate during assembly and packaging is absorbed by the stress isolation structure, thereby reducing the deformation of the pressure-sensitive film caused by the stress, thereby avoiding the deformation of the pressure-sensitive film causing the second upper electrode and the first lower electrode to be displaced in the absence of pressure input, which is beneficial to preventing the problem of zero drift and improving the accuracy of pressure measurement and the stability of long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a structural schematic diagram of one embodiment of a high-precision pressure sensitive structure provided by the present invention.

[0018] Figure 2 It is a schematic diagram of the cross-sectional structure of an upper substrate in one embodiment of a high-precision pressure-sensitive structure provided by the present invention.

[0019] Figure 3 It is a schematic structural diagram of the first upper electrode side of the upper substrate in one embodiment of a high-precision pressure-sensitive structure provided by the present invention.

[0020] Figure 4 It is a schematic structural diagram of an upper substrate facing away from a first upper electrode in one embodiment of a high-precision pressure-sensitive structure provided by the present invention.

[0021] Figure 5 The figure is a schematic diagram of the cross-sectional structure of a pressure-sensitive film in one embodiment of a high-precision pressure-sensitive structure provided by the present invention.

[0022] Figure 6 It is a schematic structural diagram of the second upper electrode side of the pressure-sensitive film in one embodiment of a high-precision pressure-sensitive structure provided by the present invention.

[0023] Figure 7 It is a schematic diagram of the cross-sectional structure of a lower substrate in one embodiment of a high-precision pressure-sensitive structure provided by the present invention.

[0024] Figure 8 It is a schematic structural diagram of the second lower electrode side of the lower substrate in one embodiment of a high-precision pressure sensitive structure provided by the present invention.

[0025] Fig. 9 It is a structural schematic diagram of a screen printing plate in one embodiment of a method for manufacturing a high-precision pressure-sensitive structure provided by the present invention.

[0026] Fig.10 The present invention provides a method for manufacturing a high-precision pressure-sensitive structure in one embodiment of the present invention. The present invention is a schematic diagram of the structure after the lower substrate is screen-printed with a second glass paste layer.

[0027] Fig.11 The present invention provides a method for manufacturing a high-precision pressure-sensitive structure in one embodiment of the present invention. The present invention is a schematic structural diagram of an upper substrate after screen printing a first glass paste layer.

[0028] Fig.12 The present invention provides a method for manufacturing a high-precision pressure-sensitive structure in which a lower substrate and a pressure-sensitive membrane are pre-fixed by glue dispensing in one embodiment.

[0029] Fig.13 The present invention provides a method for manufacturing a high-precision pressure-sensitive structure, in which an upper substrate, a lower substrate and a pressure-sensitive membrane are pre-fixed by glue dispensing in one embodiment.

[0030] Fig.14 It is a schematic diagram of the structure after gold wire bonding is completed in one embodiment of a method for manufacturing a high-precision pressure-sensitive structure provided by the present invention.

[0031] Reference numerals: 100: upper substrate; 110: first upper electrode; 120: detection through hole; 130: first limiting protrusion; 140: first pad; 200: pressure-sensitive film; 210: second upper electrode; 220: first lower electrode; 230: stress isolation structure; 231: annular recess; 240: second pad; 300: lower substrate; 310: second lower electrode; 320: second limiting protrusion; 330: third pad; 400: first bonding structure; 500: second bonding structure; 600: processing chip; 710: first alignment mark; 720: slurry unit. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Combine the following Figure 1-Figure 8 A high-precision pressure-sensitive structure of the present invention is described, comprising: The upper substrate 100 is provided with a first upper electrode 110 and a detection through hole 120; The pressure-sensitive film 200 is provided with a second upper electrode 210, a first lower electrode 220 and a stress isolation structure 230. One side of the pressure-sensitive film 200 is connected to the upper substrate 100 to form a first chamber connected to the detection through hole 120. The second upper electrode 210 and the first upper electrode 110 are both located in the first chamber and are arranged opposite to each other. A lower substrate 300 is provided with a second lower electrode 310. The other side of the pressure-sensitive film 200 is connected to the lower substrate 300 to form a second chamber. The second lower electrode 310 and the first lower electrode 220 are both located in the second chamber and are arranged opposite to each other. The stress isolation structure 230 is used to absorb stress to reduce deformation of the pressure-sensitive film 200 caused by the stress.

[0034] By providing a stress isolation structure 230 on the pressure-sensitive film 200, the stress generated during assembly and packaging of the upper substrate 100, the pressure-sensitive film 200 and the lower substrate 300 is absorbed by the stress isolation structure 230, thereby reducing the deformation of the pressure-sensitive film 200 caused by the stress, thereby preventing the second upper electrode 210 and the first lower electrode 220 from being displaced when there is no pressure input due to the deformation of the pressure-sensitive film 200, which is beneficial to preventing the problem of zero drift and improving the accuracy of pressure measurement and the stability of long-term use.

[0035] refer to Figure 1 and Figure 5 , the second upper electrode 210 and the first lower electrode 220 are located on both sides of the pressure-sensitive film 200, and correspond to the first upper electrode 110 and the second lower electrode 310 respectively. During operation, the detected medium, such as gas, liquid, etc., flows into the first chamber from the detection through hole 120. Based on the pressure of the detected medium, the pressure-sensitive film 200 will produce a corresponding degree of deformation, thereby changing the distance between the first upper electrode 110 and the second upper electrode 210 and the distance between the first lower electrode 220 and the second lower electrode 310, so that the capacitance value changes with the pressure, thereby achieving the effect of pressure measurement.

[0036] It should be noted that the first upper electrode 110 and the second upper electrode 210 form a capacitor, the first lower electrode 220 and the second lower electrode 310 form another capacitor, and the second upper electrode 210 and the first lower electrode 220 move with the pressure-sensitive film 200. For common-mode interference, such as vibration, the dual-capacitor structure can eliminate the common-mode influence and improve the accuracy of pressure measurement.

[0037] In some embodiments of the present invention, the upper substrate 100, the pressure-sensitive film 200, and the lower substrate 300 can all be made of quartz crystal material. Quartz crystal, as a piezoelectric single crystal material, has stable physical and chemical properties and can work stably in various environments. At the same time, the upper substrate 100, the pressure-sensitive film 200, and the lower substrate 300 are all made of quartz crystal material, which improves the matching of the thermal expansion coefficient of the material and avoids temperature drift caused by the mismatch of the thermal expansion coefficient of the material. In addition, the quartz crystal material has good flexibility. Compared with the silicon crystal material, the elastic modulus of the quartz crystal is half of that of the silicon crystal material. Under the same size of the pressure-sensitive film 200, the pressure-sensitive film 200 made of quartz crystal material has higher sensitivity.

[0038] In some embodiments of the present invention, the first upper electrode 110, the second upper electrode 210, the first lower electrode 220 and the second lower electrode 310 can be formed by magnetron sputtering or electron beam evaporation, using Cr as a seed layer with a thickness of 20 angstroms to 200 angstroms and Au as a metal layer with a thickness of 2000 angstroms to 5000 angstroms.

[0039] refer to Figure 1 , Figure 5 and Figure 6 In some embodiments of a high-precision pressure-sensitive structure of the present invention, the stress isolation structure 230 includes an annular recess 231 disposed on the pressure-sensitive film 200 , and the annular recess 231 surrounds the second upper electrode 210 or the first lower electrode 220 .

[0040] During the assembly process, due to the assembly stress, the over-positioned pressure-sensitive film 200 may be twisted and deformed. The structure of the annular recess can absorb the assembly stress and reduce the twisting deformation of the pressure-sensitive film 200. At the same time, the annular recess can convert the pressure-sensitive deformation of the pressure-sensitive film 200 caused by the stress from tensile and compressive deformation to bending deformation. The bending of the annular recess reduces the tensile and compressive deformation, which is beneficial to improve the sensitivity of the pressure-sensitive film 200. In addition, during the high and low temperature test, thermal stress may also cause the pressure-sensitive film 200 to be twisted and deformed. The structure of the annular recess can also effectively absorb thermal stress and reduce the twisting deformation of the pressure-sensitive film 200. In this way, stress isolation is achieved through the annular recess, which reduces the stress transferred to the part of the pressure-sensitive film 200 where the second upper electrode 210 and the first lower electrode 220 are located, and reduces the deformation of the pressure-sensitive film 200 caused by stress.

[0041] In some embodiments of the present invention, the pattern of the annular concave portion may be defined by photolithography or a mask plate, and then the annular concave portion may be formed by wet etching, sandblasting, laser engraving or other processing methods.

[0042] In some embodiments of the present invention, the stress isolation structure 230 may also be an implementation manner including a recess having other closed shapes surrounding the second upper electrode 210 or the first lower electrode 220 .

[0043] refer to Figure 1 and Figure 5 In some embodiments of a high-precision pressure-sensitive structure of the present invention, two annular recesses 231 are provided, one of the two annular recesses 231 surrounds the second upper electrode 210, and the other annular recess 231 surrounds the first lower electrode 220, and the projections of the two annular recesses 231 overlap.

[0044] By providing two annular recesses 231 that surround the second upper electrode 210 and the first lower electrode 220 respectively, the two annular recesses 231 are located on both sides of the pressure-sensitive film 200 and their projections overlap, so that the two annular recesses 231 can absorb stress more effectively, further improve the stress isolation effect, and reduce the deformation of the pressure-sensitive film 200 caused by stress.

[0045] refer to Figure 1 and Figure 3 In some embodiments of a high-precision pressure-sensitive structure of the present invention, a first bonding structure 400 is provided between the upper substrate 100 and the pressure-sensitive film 200, and the upper substrate 100 is connected to the pressure-sensitive film 200 through the first bonding structure 400 to form the first chamber; A second bonding structure 500 is disposed between the lower substrate 300 and the pressure-sensitive film 200 , and the lower substrate 300 is connected to the pressure-sensitive film 200 through the second bonding structure 500 to form the second chamber.

[0046] The upper substrate 100 is bonded to the pressure-sensitive film 200 via the first bonding structure 400 , and the lower substrate 300 is bonded to the pressure-sensitive film 200 via the second bonding structure 500 , so as to form a stable and reliable connection relationship, which is conducive to making the overall structure more stable.

[0047] In some embodiments of a high-precision pressure-sensitive structure of the present invention, the first bonding structure 400 includes a first glass paste bonding layer, the first glass paste bonding layer is annular and surrounds the first upper electrode 110 and the second upper electrode 210, and the first glass paste bonding layer is connected to the upper substrate 100 and the pressure-sensitive film 200 respectively; The second bonding structure 500 includes a second glass paste bonding layer, which is annular and surrounds the first lower electrode 220 and the second lower electrode 310 , and is connected to the lower substrate 300 and the pressure-sensitive film 200 , respectively.

[0048] The upper substrate 100 and the pressure-sensitive film 200 are bonded together via a first glass paste bonding layer, and the lower substrate 300 and the pressure-sensitive film 200 are bonded together via a second glass paste bonding layer. The first glass paste bonding layer and the second glass paste bonding layer have good air tightness, insulation and stability, and the stress generated by the bonding is small, which is beneficial to further reduce the deformation of the pressure-sensitive film 200 caused by stress.

[0049] In some embodiments of the present invention, when the upper substrate 100, the pressure-sensitive film 200, and the lower substrate 300 are all made of quartz crystal material, the thermal expansion coefficient of the first glass paste bonding layer and the thermal expansion coefficient of the second glass paste bonding layer both match the thermal expansion coefficient of the quartz crystal material.

[0050] In some embodiments of the present invention, the first bonding structure 400 and the second bonding structure 500 may also be embodiments that include a metal solder bonding layer, a silicon-silicon bonding layer, etc. that can achieve a bonding connection.

[0051] refer to Figure 1 , Figure 2 , Figure 3 , Figure 7 and Figure 8 In some embodiments of a high-precision pressure-sensitive structure of the present invention, the upper substrate 100 is provided with a first limiting protrusion 130, and the first limiting protrusion 130 is used to abut against the pressure-sensitive film 200 to limit the distance between the first upper electrode 110 and the second upper electrode 210; The lower substrate 300 is provided with a second limiting protrusion 320 , and the second limiting protrusion 320 is used to abut against the pressure-sensitive film 200 to limit the distance between the first lower electrode 220 and the second lower electrode 310 .

[0052] During the assembly process, the upper substrate 100 is bonded to the pressure-sensitive film 200 through the first glass paste bonding layer, and the lower substrate 300 is bonded to the pressure-sensitive film 200 through the second glass paste bonding layer. Heating and pressurization are required to make the glass paste molten and pressurize the upper substrate 100 close to the pressure-sensitive film 200 and the lower substrate 300 close to the pressure-sensitive film 200. By providing a first limiting protrusion 130 on the upper substrate 100 and a second limiting protrusion 320 on the lower substrate 300, when the first limiting protrusion 130 abuts against the pressure-sensitive film 200, the upper substrate 100 cannot get further close to the pressure-sensitive film 200, and when the second limiting protrusion 320 abuts against the pressure-sensitive film 200, the lower substrate 300 cannot get further close to the pressure-sensitive film 200. In this way, after heating and cooling, the glass paste forms a first glass paste bonding layer and a second glass paste bonding layer. The first limiting protrusion 130 and the second limiting protrusion 320 respectively achieve the effect of limiting the thickness of the first glass paste bonding layer and the thickness of the second glass paste bonding layer, and also limit the distance between the first upper electrode 110 and the second upper electrode 210, and the distance between the first lower electrode 220 and the second lower electrode 310, so that the distance is more stable, thereby making the capacitance value of the formed capacitor more stable, and avoiding the deterioration of the uniformity of the capacitance value due to distance fluctuation.

[0053] It should be noted that, when the upper substrate 100 and the lower substrate 300 are pressed close to the pressure-sensitive film 200 , the glass paste will be squeezed. At this time, the annular recess 231 can act as an overflow groove, thereby strictly controlling the plane size of the pressure-sensitive film 200 .

[0054] refer to Figure 1 , Figure 2 , Figure 3 , Figure 7 and Figure 8 In some embodiments of a high-precision pressure-sensitive structure of the present invention, the upper substrate 100 is provided with at least two first limiting protrusions 130, and the first limiting protrusions 130 are evenly arranged around the first glass paste bonding layer; The lower substrate 300 is provided with at least two second position-limiting protrusions 320 , and the second position-limiting protrusions 320 are evenly arranged around the second glass paste bonding layer.

[0055] By providing at least two first limiting protrusions 130 and at least two second limiting protrusions 320, and the first limiting protrusions 130 are evenly arranged around the first glass paste bonding layer, and the second limiting protrusions 320 are evenly arranged around the second glass paste bonding layer, the first limiting protrusions 130 and the second limiting protrusions 320 are more stable and reliable when abutting against the pressure-sensitive film 200, avoiding deviation due to uneven force.

[0056] In some embodiments of the present invention, the first limiting protrusion 130 and the second limiting protrusion 320 may also be annular, the first limiting protrusion 130 surrounds the first glass paste bonding layer, and the second limiting protrusion 320 surrounds the second glass paste bonding layer.

[0057] In some embodiments of the present invention, the first limiting protrusion 130 and the second limiting protrusion 320 may be formed by wet etching, sandblasting or laser etching.

[0058] refer to Figure 1 , Figure 2 and Figure 4 In some embodiments of a high-precision pressure-sensitive structure of the present invention, it also includes a processing chip 600 arranged on the upper substrate 100, the upper substrate 100 is provided with a first pad 140 connected to the first upper electrode 110, the pressure-sensitive film 200 is provided with a second pad 240 connected to the second upper electrode 210 and the first lower electrode 220 respectively, the lower substrate 300 is provided with a third pad 330 connected to the second lower electrode 310, and the processing chip 600 is connected to the first pad 140, the second pad 240 and the third pad 330 respectively.

[0059] The processing chip 600 is respectively connected to the first pad 140, the second pad 240, and the third pad 330, that is, the processing chip 600 is electrically connected to the first upper electrode 110, the second upper electrode 210, the first lower electrode 220, and the second lower electrode 310. The processing chip 600 outputs a corresponding electrical signal, which may be a digital signal, according to the change in the capacitance value of the first capacitor formed by the first upper electrode 110 and the second upper electrode 210, and the change in the capacitance value of the second capacitor formed by the first lower electrode 220 and the second lower electrode 310, thereby achieving the purpose of outputting measured pressure.

[0060] In some embodiments of the present invention, the connection between the processing chip 600 and the first pad 140 , the second pad 240 , and the third pad 330 may be achieved by gold wire bonding.

[0061] A pressure sensor provided by the present invention is described below. The pressure sensor described below and the high-precision pressure sensitive structure described above can refer to each other.

[0062] The present invention also provides a pressure sensor, comprising a sensor body, wherein the sensor body is provided with the above-mentioned high-precision pressure sensitive structure.

[0063] The sensor body may include a shell, and a detection port and an output end arranged on the shell, the detection through hole 120 is connected to the detection port, and the processing chip 600 is connected to the output end.

[0064] By providing a stress isolation structure 230 on the pressure-sensitive film 200, the stress generated during assembly and packaging of the upper substrate 100, the pressure-sensitive film 200 and the lower substrate 300 is absorbed by the stress isolation structure 230, thereby reducing the deformation of the pressure-sensitive film 200 caused by the stress, thereby preventing the second upper electrode 210 and the first lower electrode 220 from being displaced when there is no pressure input due to the deformation of the pressure-sensitive film 200, which is beneficial to preventing the problem of zero drift and improving the accuracy of pressure measurement and the stability of long-term use.

[0065] A method for manufacturing a high-precision pressure-sensitive structure provided by the present invention is described below. The method for manufacturing a high-precision pressure-sensitive structure described below and the high-precision pressure-sensitive structure described above can refer to each other.

[0066] refer to Figures 9 to 14 The present invention also provides a method for manufacturing a high-precision pressure sensitive structure, comprising: S100: preparing a screen printing plate, wherein the screen printing plate is provided with a first alignment mark portion 710 and a slurry unit 720; S200: preparing an upper substrate and a lower substrate, wherein the upper substrate is provided with a second alignment mark portion, a detection through hole 120, a first upper electrode 110, and a first pad 140 connected to the first upper electrode 110, and the lower substrate is provided with a third alignment mark portion, a second lower electrode 310, and a third pad 330 connected to the second lower electrode 310; S300: preparing a pressure-sensitive membrane, wherein the pressure-sensitive membrane is provided with a fourth alignment mark portion, a stress isolation structure 230, a second upper electrode 210, a first lower electrode 220, and a second pad 240 respectively connected to the second upper electrode 210 and the first lower electrode 220; S400: Using CCD alignment, based on the overlap of the projection of the first alignment mark part 710 and the second alignment mark part, the paste unit 720 of the screen printing plate is printed onto the upper substrate to form a first glass paste layer; based on the overlap of the projection of the first alignment mark part 710 and the third alignment mark part, the paste unit 720 of the screen printing plate is printed onto the lower substrate to form a second glass paste layer.

[0067] By combining screen printing with CCD alignment, the glass paste in the paste unit 720 can be accurately printed on the target positions of the upper substrate and the lower substrate, and it is helpful to accurately control the amount of glass paste to avoid excessive overflow of subsequent glass paste. At the same time, the screen printing method can also accurately control the boundary of the glass paste to avoid the problem of uncertain boundaries caused by the strong fluidity of the glass paste, which is helpful to improve uniformity and repeatability. The structure of the screen printing plate is as follows Fig. 9 As shown, the lower substrate and the upper substrate after screen printing are as shown in Fig.10 and Fig.11 shown.

[0068] CCD alignment (Charge-Coupled Device Alignment) is a high-precision visual positioning technology based on CCD cameras. It uses CCD cameras to capture images of target objects and achieves precise alignment of objects based on the marks in the image, namely the first alignment mark, the second alignment mark, and the third alignment mark.

[0069] In some embodiments of the present invention, the detection through hole 120 may be formed by ultrasonic drilling or wet etching. In some embodiments of the present invention, the first alignment mark portion of the screen printing plate may include a screen printing alignment mark and a wafer-level alignment mark, and the second alignment mark portion of the upper substrate and the alignment mark portion of the lower substrate may include a wafer-level alignment mark.

[0070] S500: heating the upper substrate and the lower substrate according to a first preset temperature curve to debind the first glass paste layer and the second glass paste layer, and to melt and sinter the first glass paste layer and the second glass paste layer to form a first sintered glass paste layer and a second sintered glass paste layer.

[0071] In some embodiments of the present invention, a high temperature oven can be used for heating, and the first preset temperature curve can be: heating to 150°C at a heating rate of 5°C / min, and keeping warm for 15 to 30 minutes to discharge the organic solvent; heating to 200°C, keeping warm for 30 minutes to discharge the organic binder; heating to 250°C, keeping warm for 15 to 30 minutes to activate the slurry thixotropic agent; heating to 300°C, keeping warm for 15 to 30 minutes to crystallize the first glass slurry layer and the second glass slurry layer; heating to 350°C, keeping warm for 15 to 30 minutes to melt and sinter the first glass slurry layer and the second glass slurry layer to form the first sintered glass slurry layer and the second sintered glass slurry layer; cooling to room temperature and taking out the upper substrate and the lower substrate. In this way, the debinding and sintering of the glass slurry are achieved.

[0072] S600: using a positioning device, adjusting the relative positions of the lower base sheet and the pressure-sensitive membrane so that the projections of the third positioning mark portion and the fourth positioning mark portion overlap, and adding glue between the lower base sheet and the pressure-sensitive membrane to pre-fix the lower base sheet and the pressure-sensitive membrane; S700: using a positioning device, adjusting the relative positions of the upper base sheet and the pressure-sensitive membrane so that the projections of the second positioning mark portion and the fourth positioning mark portion overlap, and adding glue between the upper base sheet and the pressure-sensitive membrane to pre-fix the upper base sheet and the pressure-sensitive membrane; Use the alignment equipment to align the upper substrate and the pressure-sensitive diaphragm, and then use glue to pre-fix them so that the upper substrate and the pressure-sensitive diaphragm are a whole. Then align the lower substrate and the pressure-sensitive diaphragm, and then use glue to fix them. In this way, the upper substrate, the pressure-sensitive diaphragm, and the lower substrate are a three-layer structure as a whole, which is convenient for subsequent clamping and heating treatment. Fig.12 , Fig.13 shown.

[0073] In some embodiments of the present invention, the dispensing may be implemented by using UV glue. After the UV glue is used to bond the upper substrate and the pressure-sensitive film, and the lower substrate and the pressure-sensitive film, the UV glue needs to be irradiated to cure the UV glue.

[0074] S800: clamping and heating the pre-fixed upper substrate, the pressure-sensitive membrane, and the lower substrate according to a second preset temperature curve and a preset pressure curve, so that the first sintered glass paste layer forms a first glass paste bonding layer to bond the upper substrate to the pressure-sensitive membrane, and the second sintered glass paste layer forms a second glass paste bonding layer to bond the lower substrate to the pressure-sensitive membrane, and the pre-fixed glue is carbonized and decomposed; In some embodiments of the present invention, a variable load muffle furnace can be used for clamping heating, and the second preset temperature curve and the preset pressure curve can be: applying a preload pressure of 5 to 10 kg to the upper substrate, pressure-sensitive diaphragm and lower substrate of the three-layer structure to fix the upper substrate, pressure-sensitive diaphragm and lower substrate of the three-layer structure; starting from room temperature, heating up to 520°C at a heating rate of 5°C / min, keeping warm for 15 to 30 minutes, and the load pressure at the insulation point is 150 to 250 kg; after the insulation is completed, cool with the furnace, and when the temperature drops to 250°C to 260°C, remove the load pressure; when the temperature drops to 150°C, open the furnace door and quickly cool to room temperature. In this process, the glue will automatically carbonize and decompose, such as Fig.14 Dispense shown exploded.

[0075] S900: performing a scribing process on the bonded upper substrate sheet, the pressure-sensitive film sheet and the lower substrate sheet to form a bonded upper substrate 100, a pressure-sensitive film 200 and a lower substrate 300; S1000: Fix the processing chip 600 on the upper substrate 100, and use bonding equipment to connect the processing chip 600 to the first pad 140, the second pad 240, and the third pad 330 respectively through gold wire bonding.

[0076] After the bonding is completed, a dicing process is performed to divide the upper substrate 100, the pressure-sensitive film 200 and the lower substrate 300 into a plurality of bonded upper substrates 100, the pressure-sensitive film 200 and the lower substrate 300, and then a processing chip 600 is added to each of the bonded upper substrates 100, the pressure-sensitive film 200 and the lower substrate 300. The processing chip 600 is connected to the first pad 140, the second pad 240 and the third pad 330 by gold wire bonding, that is, the processing chip 600 is electrically connected to the first upper electrode 110, the second upper electrode 210, the first lower electrode 220 and the second lower electrode 310. In this way, the processing chip 600 outputs a corresponding electrical signal based on the capacitance value change of the first capacitor formed by the first upper electrode 110 and the second upper electrode 210 and the capacitance value change of the second capacitor formed by the first lower electrode 220 and the second lower electrode 310, thereby achieving the effect of pressure measurement.

[0077] In some embodiments of the present invention, the processing chip 600 can be fixed to the upper substrate 100 by epoxy adhesive bonding, using a forced air oven starting from room temperature, with a heating rate of 5°C / min, a curing temperature of 80~120 degrees, and a curing time of 15~30 minutes to cure the epoxy adhesive, and then cool it in the oven.

[0078] In some embodiments of the present invention, the diameter of the gold wire used in gold wire bonding is 25 um, and the tensile strength of the gold wire is 5-8 grams.

[0079] In some embodiments of the present invention, the upper substrate and the lower substrate may be made of Z-cut quartz crystal, and the second alignment mark portion and the third alignment mark portion may be formed by laser marking, wet etching or dry etching.

[0080] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0081] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0082] All actions to obtain signals, information or data in this application are carried out in compliance with the relevant data protection laws and policies of the location and with the authorization given by the owner of the corresponding device.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-precision pressure-sensitive structure, characterized in that: include: An upper substrate (100) provided with a first upper electrode (110) and a detection through hole (120); A pressure-sensitive film (200) is provided with a second upper electrode (210), a first lower electrode (220) and a stress isolation structure (230); one side of the pressure-sensitive film (200) is connected to the upper substrate (100) to form a first chamber connected to the detection through hole (120); the second upper electrode (210) and the first upper electrode (110) are both located in the first chamber and are arranged opposite to each other; A lower substrate (300) is provided with a second lower electrode (310); the other side of the pressure-sensitive film (200) is connected to the lower substrate (300) to form a second chamber; the second lower electrode (310) and the first lower electrode (220) are both located in the second chamber and are arranged opposite to each other; The stress isolation structure (230) is used to absorb stress so as to reduce deformation of the pressure-sensitive film (200) caused by the stress.

2. A high-precision pressure sensitive structure according to claim 1, characterized in that: The stress isolation structure (230) comprises an annular recess (231) arranged on the pressure-sensitive film (200), wherein the annular recess (231) surrounds the second upper electrode (210) or the first lower electrode (220).

3. A high-precision pressure sensitive structure according to claim 2, characterized in that: Two annular recesses (231) are provided, one of the two annular recesses (231) surrounds the second upper electrode (210), and the other annular recess (231) surrounds the first lower electrode (220), and the projections of the two annular recesses (231) overlap.

4. A high-precision pressure sensitive structure according to claim 1, characterized in that: A first bonding structure (400) is provided between the upper substrate (100) and the pressure-sensitive film (200), and the upper substrate (100) is connected to the pressure-sensitive film (200) via the first bonding structure (400) to form the first chamber; A second bonding structure (500) is provided between the lower substrate (300) and the pressure-sensitive film (200), and the lower substrate (300) is connected to the pressure-sensitive film (200) via the second bonding structure (500) to form the second chamber.

5. A high-precision pressure sensitive structure according to claim 4, characterized in that: The first bonding structure (400) comprises a first glass paste bonding layer, the first glass paste bonding layer is ring-shaped and surrounds the first upper electrode (110) and the second upper electrode (210), and the first glass paste bonding layer is respectively connected to the upper substrate (100) and the pressure-sensitive film (200); The second bonding structure (500) comprises a second glass paste bonding layer, the second glass paste bonding layer is ring-shaped and surrounds the first lower electrode (220) and the second lower electrode (310), and the second glass paste bonding layer is respectively connected to the lower substrate (300) and the pressure-sensitive film (200).

6. A high-precision pressure sensitive structure according to claim 5, characterized in that: The upper substrate (100) is provided with a first limiting convex portion (130), and the first limiting convex portion (130) is used to abut against the pressure-sensitive film (200) to limit the distance between the first upper electrode (110) and the second upper electrode (210); The lower substrate (300) is provided with a second limiting protrusion (320), and the second limiting protrusion (320) is used to abut against the pressure-sensitive film (200) to limit the distance between the first lower electrode (220) and the second lower electrode (310).

7. A high-precision pressure sensitive structure according to claim 6, characterized in that: The upper substrate (100) is provided with at least two first limiting protrusions (130), and the first limiting protrusions (130) are evenly arranged around the first glass paste bonding layer; The lower substrate (300) is provided with at least two second position-limiting protrusions (320), and the second position-limiting protrusions (320) are evenly arranged around the second glass paste bonding layer.

8. The high-precision pressure sensitive structure according to claim 1, characterized in that: The invention also includes a processing chip (600) arranged on the upper substrate (100); the upper substrate (100) is provided with a first pad (140) connected to the first upper electrode (110); the pressure-sensitive film (200) is provided with a second pad (240) connected to the second upper electrode (210) and the first lower electrode (220), respectively; the lower substrate (300) is provided with a third pad (330) connected to the second lower electrode (310); and the processing chip (600) is connected to the first pad (140), the second pad (240) and the third pad (330), respectively.

9. A pressure sensor, characterized in that: The sensor comprises a sensor body, wherein the sensor body is provided with a high-precision pressure sensitive structure as claimed in any one of claims 1 to 8.

10. A method for manufacturing a high-precision pressure sensitive structure, characterized in that: A high-precision pressure-sensitive structure as claimed in any one of claims 1 to 8, comprising: Preparing a screen printing plate, wherein the screen printing plate is provided with a first alignment mark portion (710) and a slurry unit (720); An upper substrate sheet and a lower substrate sheet are prepared, wherein the upper substrate sheet is provided with a second alignment mark portion, a first upper electrode (110), and a first pad (140) connected to the first upper electrode (110), and the lower substrate sheet is provided with a third alignment mark portion, a second lower electrode (310), and a third pad (330) connected to the second lower electrode (310); Preparing a pressure-sensitive membrane, the pressure-sensitive membrane being provided with a fourth alignment mark portion, a stress isolation structure (230), a second upper electrode (210), a first lower electrode (220), and a second pad (240) respectively connected to the second upper electrode (210) and the first lower electrode (220); Using CCD alignment, based on the overlap of the projections of the first alignment mark portion (710) and the second alignment mark portion, printing the paste unit (720) of the screen printing plate onto the upper substrate to form a first glass paste layer, and based on the overlap of the projections of the first alignment mark portion (710) and the third alignment mark portion, printing the paste unit (720) of the screen printing plate onto the lower substrate to form a second glass paste layer; The upper substrate and the lower substrate are heated according to a first preset temperature curve to debind the first glass paste layer and the second glass paste layer, and the first glass paste layer and the second glass paste layer are melted and sintered to form a first sintered glass paste layer and a second sintered glass paste layer; Using an alignment device, adjusting the relative position of the lower base sheet and the pressure-sensitive membrane so that the projections of the third alignment mark portion and the fourth alignment mark portion overlap, and adding glue between the lower base sheet and the pressure-sensitive membrane to pre-fix the lower base sheet and the pressure-sensitive membrane; Using a positioning device, adjusting the relative position of the upper base sheet and the pressure-sensitive membrane so that the projections of the second positioning mark portion and the fourth positioning mark portion overlap, and adding glue between the upper base sheet and the pressure-sensitive membrane to pre-fix the upper base sheet and the pressure-sensitive membrane; The pre-fixed upper substrate, the pressure-sensitive membrane and the lower substrate are clamped and heated according to a second preset temperature curve and a preset pressure curve, so that the first sintered glass paste layer forms a first glass paste bonding layer to bond the upper substrate to the pressure-sensitive membrane, and the second sintered glass paste layer forms a second glass paste bonding layer to bond the lower substrate to the pressure-sensitive membrane, and the pre-fixed glue is carbonized and decomposed; Performing a dicing process on the bonded upper substrate sheet, the pressure-sensitive film sheet, and the lower substrate sheet to form a bonded upper substrate (100), a pressure-sensitive film (200), and a lower substrate (300); The processing chip (600) is fixed on the upper substrate (100), and the processing chip (600) is respectively connected to the first pad (140), the second pad (240), and the third pad (330) by gold wire bonding using bonding equipment.

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