Quartz pressure sensitive structure, pressure sensor and manufacturing method

Abstract

The invention relates to the technical field of pressure sensors, and provides a quartz pressure sensitive structure and a manufacturing method, and the structure comprises an upper substrate which is provided with a first upper electrode and a first through hole; the pressure sensing film is provided with a second upper electrode and a first lower electrode, and the pressure sensing film is connected with the upper substrate to form a first cavity communicated with the first through hole; and the lower substrate is provided with a second lower electrode, and the lower substrate is connected with the pressure sensing film to form a second cavity. The upper substrate, the pressure-sensitive film and the lower substrate are all made of quartz crystal materials, so that thermal expansion coefficients of the materials are matched, packaging stress can be reduced, the problem of temperature drift is further prevented, under the same pressure-sensitive film size, the pressure-sensitive film made of the quartz crystal materials is higher in sensitivity, the area of a quartz capacitor can be larger than that of a silicon capacitor, and the reliability of the pressure-sensitive film is improved. The nominal capacitance value of the quartz capacitor is one order of magnitude larger than the nominal capacitance value of the silicon capacitor, the anti-interference performance of stray capacitance can be enhanced, and the temperature drift and time drift performance can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitive pressure sensors, and particularly to a quartz pressure-sensitive structure, a pressure sensor, and a manufacturing method thereof. Background Art

[0002] A capacitive pressure sensor is a sensor that works based on the capacitance principle and is used to measure pressure changes. When the pressure changes, it will cause the pressure-sensitive film to deform, making the distance between the two electrodes forming the capacitor change, and thus the capacitance value changes. There is a correlation between the pressure and the capacitance value, and based on this, the pressure measurement is realized.

[0003] In the prior art, the pressure sensor is mainly a silicon micro-capacitive pressure sensor. However, the silicon-glass bonding method used in the silicon micro-capacitive pressure sensor has large packaging stress, resulting in temperature drift. Moreover, the nominal capacitance value of the silicon micro-capacitor is small, and it is extremely vulnerable to the influence of external stray capacitance, resulting in poor temperature drift and time drift. Summary of the Invention

[0004] The present invention provides a quartz pressure-sensitive structure, a pressure sensor, and a manufacturing method thereof to solve the defects in the prior art that the pressure sensor has large stress resulting in temperature drift and small nominal capacitance value resulting in being easily affected by stray capacitance.

[0005] The present invention provides a quartz pressure-sensitive structure, comprising: An upper substrate provided with a first upper electrode and a first through hole; A pressure-sensitive film provided with a second upper electrode and a first lower electrode. The second upper electrode is located on one side of the pressure-sensitive film, and the first lower electrode is located on the other side of the pressure-sensitive film. The pressure-sensitive film is connected to the upper substrate to form a first chamber communicating with the first through hole. The first upper electrode and the second upper electrode are both located in the first chamber and are oppositely arranged; A lower substrate provided with a second lower electrode. The lower substrate is connected to the pressure-sensitive film to form a second chamber. The first lower electrode and the second lower electrode are both located in the second chamber and are oppositely arranged; Wherein, the upper substrate, the pressure-sensitive film, and the lower substrate are all made of quartz crystal material.

[0006] According to a quartz pressure-sensitive structure provided by the present invention, the lower substrate is further provided with a second through hole communicating with the second chamber.

[0007] According to a quartz pressure-sensitive structure provided by the present invention, a first glass paste bonding layer is disposed between the upper substrate and the pressure-sensitive film. The first glass paste bonding layer is respectively connected to the upper substrate and the pressure-sensitive film to form the first chamber. The thermal expansion coefficients of the first glass paste bonding layer respectively match the thermal expansion coefficients of the upper substrate and the pressure-sensitive film.

[0008] According to a quartz pressure-sensitive structure provided by the present invention, the upper substrate is provided with at least one first boss, and the first boss is used to abut against the pressure-sensitive film to control the thickness of the first glass paste bonding layer.

[0009] According to a quartz pressure-sensitive structure provided by the present invention, a second glass paste bonding layer is disposed between the lower substrate and the pressure-sensitive film. The second glass paste bonding layer is respectively connected to the lower substrate and the pressure-sensitive film to form the second chamber. The thermal expansion coefficients of the second glass paste bonding layer respectively match the thermal expansion coefficients of the upper substrate and the pressure-sensitive film.

[0010] According to a quartz pressure-sensitive structure provided by the present invention, the lower substrate is provided with at least one second boss, and the second boss is used to abut against the pressure-sensitive film to control the thickness of the second glass paste bonding layer.

[0011] According to a quartz pressure-sensitive structure provided by the present invention, it further includes a processing chip. The processing chip is disposed on the upper substrate. The upper substrate is provided with a first pad connected to the first upper electrode. The pressure-sensitive film is provided with a second pad connected to the second upper electrode and the first lower electrode. The lower substrate is provided with a third pad connected to the second lower electrode. The processing chip is respectively connected to the first pad, the second pad, and the third pad.

[0012] According to a quartz pressure-sensitive structure provided by the present invention, the processing chip is respectively connected to the first pad, the second pad, and the third pad through bonding gold wires. The third pad is located at the edge of the lower substrate. A first connection opening corresponding to the third pad is provided at the edge of the pressure-sensitive film. The second pad is located at the edge of the pressure-sensitive film. A second connection opening corresponding to the second pad is provided at the edge of the upper substrate. The first connection opening and the second connection opening are used for the bonding gold wires to pass through.

[0013] The present invention further provides a pressure sensor, including: a sensor housing and the above-mentioned quartz pressure-sensitive structure disposed in the sensor housing. The sensor housing is provided with a first detection end, and the first detection end is communicated with the first through hole.

[0014] The present invention also provides a manufacturing method for a quartz pressure-sensitive structure, which is applied to the above-mentioned quartz pressure-sensitive structure, and includes: Preparing a screen printing plate, the screen printing plate being provided with a first alignment mark portion and a paste unit; Preparing an upper quartz crystal wafer and a lower quartz crystal wafer, the upper quartz crystal wafer being provided with a second alignment mark portion, a first boss, a first upper electrode, and a first pad connected to the first upper electrode, and the lower quartz crystal wafer being provided with a third alignment mark portion, a second boss, a second lower electrode, and a third pad connected to the second lower electrode; Preparing a pressure-sensitive quartz crystal wafer, the pressure-sensitive film being provided with a fourth alignment mark portion, 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 projection coincidence of the first alignment mark portion and the second alignment mark portion, printing the paste unit of the screen printing plate onto the upper quartz crystal wafer to form a first glass paste layer, and based on the projection coincidence of the first alignment mark portion and the third alignment mark portion, printing the paste unit of the screen printing plate onto the lower quartz crystal wafer to form a second glass paste layer; Heating the upper quartz crystal wafer and the lower quartz crystal wafer according to a first preset temperature curve to cause the first glass paste layer and the second glass paste layer to degum, and causing the first glass paste layer and the second glass paste layer to melt and sinter to form a first sintered glass paste layer and a second sintered glass paste layer; Using an alignment device, adjusting the relative positions of the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer so that the projection of the third alignment mark portion coincides with the projection of the fourth alignment mark portion, and adding glue between the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer to pre-fix the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer; Using an alignment device, adjusting the relative positions of the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer so that the projection of the second alignment mark portion coincides with the projection of the fourth alignment mark portion, and adding glue between the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer to pre-fix the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer; Clamping and heating the pre-fixed upper quartz crystal wafer, the pressure-sensitive quartz crystal wafer, and the lower quartz crystal wafer according to a second preset temperature curve and a preset pressure curve, causing the first sintered glass paste layer to form a first glass paste bonding layer to bond the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer, causing the second sintered glass paste layer to form a second glass paste bonding layer to bond the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer, and causing the pre-fixed glue to carbonize and decompose; The bonded upper quartz crystal wafer, the pressure-sensitive quartz crystal wafer, and the lower quartz crystal wafer are scribed to form a bonded upper substrate, a pressure-sensitive film, and a lower substrate; The processing chip is fixed on the upper substrate, and a bonding device is used to connect the processing chip to the first pad, the second pad, and the third pad respectively through gold wire bonding.

[0015] A quartz pressure-sensitive structure, a pressure sensor, and a manufacturing method provided by the present invention have at least the following beneficial effects: A second upper electrode and a first lower electrode are respectively arranged on both sides of the pressure-sensitive film. The second upper electrode and the first upper electrode of the upper substrate form a first capacitor, and the first lower electrode and the second lower electrode of the lower substrate form a second capacitor. The first through hole communicates with the first chamber to input external pressure, causing the pressure-sensitive film to deform and drive the second upper electrode and the first lower electrode to move. Consequently, the capacitance values of the first capacitor and the second capacitor change accordingly. Based on the correlation between the capacitance value change and the pressure, the purpose of detecting pressure change is achieved. The upper substrate, the pressure-sensitive film, and the lower substrate are all made of quartz crystal material, enabling the material thermal expansion coefficients of the upper substrate, the pressure-sensitive film, and the lower substrate to match, which is beneficial for reducing packaging stress and thus preventing temperature drift problems. At the same time, compared with silicon material, the elastic modulus of quartz crystal material is about half of that of silicon material, and the quartz crystal material has better flexibility. Under the same pressure-sensitive film size, the pressure-sensitive film made of quartz crystal material has higher sensitivity. In addition, due to the higher mechanical strength, lower thermal expansion coefficient, and strong chemical stability of the quartz crystal material, the quartz capacitor area can be made larger than the silicon capacitor area, making the nominal capacitance value of the quartz capacitor one order of magnitude larger than that of the silicon capacitor, which is beneficial for enhancing the anti-interference ability against stray capacitance and improving the temperature drift and time drift performance. Description of the Drawings

[0016] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

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

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

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

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

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

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

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

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

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

[0026] Figure 10 It is a schematic structural diagram of the lower substrate sheet after screen printing the second glass paste layer in one embodiment of a manufacturing method of a quartz pressure-sensitive structure provided by the present invention.

[0027] Figure 11 It is a schematic structural diagram of the upper substrate sheet after screen printing the first glass paste layer in one embodiment of a manufacturing method of a quartz pressure-sensitive structure provided by the present invention.

[0028] Figure 12 It is a schematic structural diagram of the lower substrate sheet and the pressure-sensitive film sheet pre-fixed by dispensing in one embodiment of a manufacturing method of a quartz pressure-sensitive structure provided by the present invention.

[0029] Figure 13 It is a schematic structural diagram of the upper substrate sheet, the lower substrate sheet, and the pressure-sensitive film sheet pre-fixed by dispensing in one embodiment of a manufacturing method of a quartz pressure-sensitive structure provided by the present invention.

[0030] Figure 14 It is a schematic structural diagram after completing wire bonding in one embodiment of a manufacturing method of a quartz pressure-sensitive structure provided by the present invention.

[0031] Reference numerals: 100: Upper substrate; 110: First upper electrode; 120: First through-hole; 130: First boss; 140: First pad; 150: First connection opening; 200: Pressure-sensitive film; 210: Second upper electrode; 220: First lower electrode; 230: Second pad; 240: Second connection opening; 300: Lower substrate; 310: Second lower electrode; 320: Second through-hole; 330: Second boss; 340: Third pad; 400: First glass paste bonding layer; 500: Second glass paste bonding layer; 600: Processing chip; 710: First alignment mark portion; 720: Paste unit. Detailed implementation manners

[0032] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0033] The following will be combined with Figures 1-8 Describe a quartz pressure-sensitive structure of the present invention, which is characterized by including: An upper substrate 100, provided with a first upper electrode 110 and a first through-hole 120; A pressure-sensitive film 200, provided with a second upper electrode 210 and a first lower electrode 220. The second upper electrode 210 is located on one side of the pressure-sensitive film 200, and the first lower electrode 220 is located on the other side of the pressure-sensitive film 200. The pressure-sensitive film 200 is connected to the upper substrate 100 to form a first chamber communicating with the first through-hole 120. The first upper electrode 110 and the second upper electrode 210 are both located in the first chamber and the first upper electrode 110 and the second upper electrode 210 are arranged opposite to each other; A lower substrate 300, provided with a second lower electrode 310. The lower substrate 300 is connected to the pressure-sensitive film 200 to form a second chamber. The first lower electrode 220 and the second lower electrode 310 are both located in the second chamber and the first lower electrode 220 and the second lower electrode 310 are arranged opposite to each other; Wherein, the upper substrate 100, the pressure-sensitive film 200, and the lower substrate 300 are all made of quartz crystal material.

[0034] On both sides of the pressure-sensitive film 200, a second upper electrode 210 and a first lower electrode 220 are respectively provided. The second upper electrode 210 and the first upper electrode 110 of the upper substrate 100 form a first capacitor, and the first lower electrode 220 and the second lower electrode 310 of the lower substrate 300 form a second capacitor. The first through hole 120 communicates with the first chamber to input external pressure, causing the pressure-sensitive film 200 to deform and drive the second upper electrode 210 and the first lower electrode 220 to move. Consequently, the capacitance values of the first capacitor and the second capacitor change accordingly. Based on the correlation between the capacitance value change and the pressure, the purpose of detecting the pressure change is achieved.

[0035] The upper substrate 100, the pressure-sensitive film 200, and the lower substrate 300 are all made of quartz crystal material, enabling the material thermal expansion coefficients of the upper substrate 100, the pressure-sensitive film 200, and the lower substrate 300 to match. This is beneficial for reducing the packaging stress and thereby preventing the temperature drift problem. At the same time, compared with silicon material, the elastic modulus of the quartz crystal material is approximately half of that of the silicon material, and the quartz crystal material has better flexibility. With the same size of the pressure-sensitive film 200, the pressure-sensitive film 200 made of quartz crystal material has higher sensitivity. In addition, due to the higher mechanical strength, lower thermal expansion coefficient, and strong chemical stability of the quartz crystal material, the area of the quartz capacitor can be made larger than that of the silicon capacitor, making the nominal capacitance value of the quartz capacitor one order of magnitude larger than that of the silicon capacitor. This is beneficial for enhancing the anti-interference ability against stray capacitance and improving the temperature drift and time drift performance.

[0036] 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. Chromium is used as the seed layer with a thickness of 20 Å to 200 Å, and gold is used as the metal layer with a thickness of 2000 Å to 5000 Å.

[0037] In some embodiments of the present invention, an external medium to be detected, such as liquid, gas, etc., enters the first chamber through the first through hole 120, forming a pressure applied to one side of the pressure-sensitive film 200. The second chamber on the other side of the pressure-sensitive film 200 can be a sealed vacuum chamber to detect the absolute pressure of the input pressure relative to the vacuum, and a barometric pressure sensor can be formed subsequently.

[0038] Reference Figure 1 、 Figure 7 and Figure 8 In some embodiments of a quartz pressure-sensitive structure of the present invention, the lower substrate 300 is further provided with a second through hole 320 communicating with the second chamber.

[0039] A second through hole 320 communicating with the second chamber is provided in the lower substrate 300, and the medium to be detected outside enters the second chamber through the second through hole 320, forming a pressure applied to the other side of the pressure-sensitive film 200. Thus, the pressure difference between the pressures in the first chamber on both sides of the pressure-sensitive film 200 and the pressure in the second chamber will cause the pressure-sensitive film 200 to deform, and further cause the capacitance value of the first capacitor formed by the first upper electrode 110 and the second upper electrode 210, and the capacitance value of the second capacitor formed by the first lower electrode 220 and the second lower electrode 310 to change, making the capacitance value change associated with the pressure difference, achieving the effect of measuring the pressure difference, and a differential pressure sensor can be formed subsequently.

[0040] It should be noted that in the present invention, capacitors are respectively provided on both sides of the pressure-sensitive film 200, that is, the first upper electrode 110 and the second upper electrode 210 form a first capacitor, and the first lower electrode 220 and the second lower electrode 310 form a second capacitor. Moreover, the second upper electrode 210 of the first capacitor and the first lower electrode 220 of the second capacitor move together with the pressure-sensitive film 200. For common-mode interference, such as vibration, it will have the same impact on the first capacitor and the second capacitor. The structure of the double capacitor can eliminate the common-mode influence, which is beneficial to improving the accuracy of pressure measurement.

[0041] Reference Figure 1 and Figure 3 In some embodiments of a quartz pressure-sensitive structure of the present invention, a first glass paste bonding layer 400 is provided between the upper substrate 100 and the pressure-sensitive film 200. The first glass paste bonding layer 400 is respectively connected to the upper substrate 100 and the pressure-sensitive film 200 to form the first chamber, and the thermal expansion coefficients of the first glass paste bonding layer 400 match the thermal expansion coefficients of the upper substrate 100 and the pressure-sensitive film 200 respectively.

[0042] By using a thermal expansion coefficient that matches the thermal expansion coefficients of the upper substrate 100 and the pressure-sensitive film 200, the upper substrate 100 is bonded to the pressure-sensitive film 200 through the first glass paste bonding layer 400. Due to the matching of the thermal expansion coefficients, thermal stress and mechanical stress can be reduced, problems such as cracking and delamination can be avoided, and the pressure-sensitive film 200 can be prevented from being distorted due to gravity, which is beneficial to improving the bonding reliability between the upper substrate 100 and the pressure-sensitive film 200. Thus, on the basis that both the upper substrate 100 and the pressure-sensitive film 200 adopt quartz crystal materials, the first glass paste bonding layer 400 with a matching thermal expansion coefficient is further used to bond the two, which is beneficial to reducing the stress generated by bonding, enhancing the reliability and stability of the bonding, and at the same time is beneficial to preventing the pressure-sensitive film 200 from being distorted and deformed due to stress, avoiding zero drift. In addition, the matching of the thermal expansion coefficients can also prevent the pressure-sensitive film 200 from being deformed due to temperature change, avoiding temperature drift, and making the pressure measurement more accurate and reliable.

[0043] The glass paste can adjust the component ratio according to requirements, so that the thermal expansion coefficient of the first glass paste bonding layer 400 formed after sintering matches the thermal expansion coefficients of the upper substrate 100 and the pressure-sensitive film 200. At the same time, the first glass paste bonding layer 400 has good sealing performance, temperature stability and electrical insulation performance, and is suitable for the application environment of capacitive pressure sensing.

[0044] Reference Figure 1 、 Figure 2 and Figure 3 In some embodiments of a quartz pressure-sensitive structure of the present invention, at least one first boss 130 is provided on the upper substrate 100, and the first boss 130 is used to abut against the pressure-sensitive film 200 to control the thickness of the first glass paste bonding layer 400.

[0045] By providing at least one first boss 130 on the upper substrate 100, when the upper substrate 100 and the pressure-sensitive film 200 are bonded, pressure and heat are applied to make the upper substrate 100, the pressure-sensitive film 200 and the glass paste in close contact. The glass paste is sintered to form the first glass paste bonding layer 400 to complete the bonding. During this process, the first boss 130 on the upper substrate 100 abuts against the pressure-sensitive film 200, which can limit the further approach of the upper substrate 100 and the pressure-sensitive film 200, realize the control of the thickness of the first glass paste bonding layer 400, and at the same time can also control the distance between the first upper electrode 110 and the second upper electrode 210, and further accurately control the initial capacitance value of the first capacitor formed by the first upper electrode 110 and the second upper electrode 210.

[0046] By providing two or more first bosses 130, when the first bosses 130 abut against the pressure-sensitive film 200, the relative position of the upper substrate 100 and the pressure-sensitive film 200 can be made more stable, and the pressure on the pressure-sensitive film 200 is also more uniform, which is beneficial to avoiding excessive local pressure.

[0047] Reference Figure 1 and Figure 8 In some embodiments of a quartz pressure-sensitive structure of the present invention, a second glass paste bonding layer 500 is provided between the lower substrate 300 and the pressure-sensitive film 200. The second glass paste bonding layer 500 is respectively connected to the lower substrate 300 and the pressure-sensitive film 200 to form the second chamber, and the thermal expansion coefficient of the second glass paste bonding layer 500 matches the thermal expansion coefficients of the upper substrate 100 and the pressure-sensitive film 200 respectively.

[0048] Similar to the first glass paste bonding layer 400, by using a coefficient of thermal expansion that matches those of the lower substrate 300 and the pressure-sensitive film 200, the lower substrate 300 is bonded to the pressure-sensitive film 200 through the second glass paste bonding layer 500. Due to the matching of the coefficients of thermal expansion, thermal stress and mechanical stress are reduced, problems such as cracking and delamination are avoided, and the pressure-sensitive film 200 is prevented from being distorted by gravity, which is beneficial to improving the bonding reliability between the upper substrate 100 and the pressure-sensitive film 200. Thus, on the basis that both the lower substrate 300 and the pressure-sensitive film 200 are made of quartz crystal material, the second glass paste bonding layer 500 with a matched coefficient of thermal expansion is further used to bond the two, which is beneficial to reducing the stress generated by bonding, enhancing the bonding reliability and stability, and at the same time is beneficial to preventing the pressure-sensitive film 200 from being distorted by stress and avoiding zero drift. In addition, due to the matching of the coefficients of thermal expansion, the pressure-sensitive film 200 can also be prevented from being deformed due to temperature changes and avoiding temperature drift, making the pressure measurement more accurate and reliable.

[0049] The glass paste can adjust the composition ratio according to requirements so that the coefficient of thermal expansion of the second glass paste bonding layer 500 formed after sintering matches those of the lower substrate 300 and the pressure-sensitive film 200. At the same time, the second glass paste bonding layer 500 has good sealing performance, temperature stability, and electrical insulation performance, which is suitable for the application environment of capacitive pressure sensing.

[0050] Reference Figure 1 、 Figure 7 and Figure 8 In some embodiments of a quartz pressure-sensitive structure of the present invention, at least one second boss 330 is provided on the lower substrate 300, and the second boss 330 is used to abut against the pressure-sensitive film 200 to control the thickness of the second glass paste bonding layer 500.

[0051] By providing at least one second boss 330 on the lower substrate 300, when the lower substrate 300 and the pressure-sensitive film 200 are bonded, the second boss 330 on the lower substrate 300 abuts against the pressure-sensitive film 200, which can limit the further approach of the lower substrate 300 and the pressure-sensitive film 200, realize the control of the thickness of the second glass paste bonding layer 500, and at the same time can also control the distance between the first lower electrode 220 and the second lower electrode 310, thereby being able to accurately control the initial capacitance value of the second capacitor formed by the first lower electrode 220 and the second lower electrode 310.

[0052] By providing two or more second bosses 330, when the second bosses 330 abut against the pressure-sensitive film 200, the relative position of the lower substrate 300 and the pressure-sensitive film 200 is more stable, and the pressure on the pressure-sensitive film 200 is also more uniform, which is beneficial to avoiding excessive local pressure.

[0053] Reference Figure 1, Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 and Figure 14 , in some embodiments of a quartz pressure-sensitive structure of the present invention, it further includes a processing chip 600. The processing chip 600 is disposed 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 230 connected to the second upper electrode 210 and the first lower electrode 220. The lower substrate 300 is provided with a third pad 340 connected to the second lower electrode 310. The processing chip 600 is respectively connected to the first pad 140, the second pad 230, and the third pad 340.

[0054] The processing chip 600 is electrically connected to the first upper electrode 110 by connecting to the first pad 140, electrically connected to the second upper electrode 210 and the first lower electrode 220 by connecting to the second pad 230, and electrically connected to the second lower electrode 310 by connecting to the third pad 340. The processing chip 600 is equivalent to being electrically connected to a first capacitor formed by the first upper electrode 110 and the second upper electrode 210 and a second capacitor formed by the first lower electrode 220 and the second lower electrode 310. The processing chip 600 outputs corresponding electrical signals, which can be digital signals, according to the capacitance value changes of the first capacitor and the second capacitor to reflect the magnitude of the detected pressure. Thus, integrating the processing chip 600 on the upper substrate 100 is beneficial for making the structure more compact and facilitating subsequent packaging processing.

[0055] Reference Figure 1 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 and Figure 14 , in some embodiments of a quartz pressure-sensitive structure of the present invention, the processing chip 600 is respectively connected to the first pad 140, the second pad 230, and the third pad 340 by bonding wires. The third pad 340 is located at the edge of the lower substrate 300. The edge of the pressure-sensitive film 200 is provided with a first connection opening 150 corresponding to the third pad 340. The second pad 230 is located at the edge of the pressure-sensitive film 200. The edge of the upper substrate 100 is provided with a second connection opening 240 corresponding to the second pad 230. The first connection opening 150 and the second connection opening 240 are used for the bonding wires to pass through.

[0056] The pins of the processing chip 600 are connected to the first pad 140, the second pad 230, and the third pad 340 through bonding. For the three-layer structure of the upper substrate 100, the pressure-sensitive film 200, and the lower substrate 300, in order to enable the bonding gold wires used for connection to be more conveniently connected to the pads, the second pad 230 is arranged at the edge of the pressure-sensitive film 200. At the same time, the upper substrate 100 is provided with a second connection opening 240 corresponding to the second pad 230, so that when bonding, the bonding gold wire can pass through the second connection opening 240 and be conveniently welded to the second pad 230. Similarly, by arranging the third pad 340 at the edge of the lower substrate 300, and at the same time, the pressure-sensitive film 200 is provided with a first connection opening 150 corresponding to the third pad 340 at the edge, the bonding gold wire can pass through the first connection opening 150 and be conveniently connected to the third pad 340. In this way, by arranging the second pad 230 and the third pad 340 at the edge, and at the same time, the second connection opening 240 and the first connection opening 150 are arranged at the edges of the upper substrate 100 and the pressure-sensitive film 200, it is convenient to perform the bonding process.

[0057] In some embodiments of the present invention, the bonding gold wire connecting the third pad 340 can be connected to the third pad 340 after passing through the second connection opening 240 and the first connection opening 150; or other connection openings are provided on the upper substrate 100, and the bonding gold wire passes through the connection opening and the first connection opening 150 and then is connected to the third pad 340. The bonding gold wire connecting the second pad 230 is connected to the second pad 230 after passing through the second connection opening 240.

[0058] A pressure sensor provided by the present invention will be described below. A pressure sensor described below can be mutually corresponding and referred to with a quartz pressure-sensitive structure described above.

[0059] The present invention provides a pressure sensor, including: a sensor housing and the above-mentioned quartz pressure-sensitive structure arranged in the sensor housing. The sensor housing is provided with a first detection end, and the first detection end is communicated with the first through hole 120.

[0060] In the sensor housing, the upper substrate 100, the pressure-sensitive film 200, and the lower substrate 300 form a three-layer structure. Second upper electrodes 210 and first lower electrodes 220 are respectively arranged on both sides of the pressure-sensitive film 200. The second upper electrode 210 and the first upper electrode 110 of the upper substrate 100 form a first capacitor, and the first lower electrode 220 and the second lower electrode 310 of the lower substrate 300 form a second capacitor. The first through hole 120 is communicated with the first chamber to input external pressure, so that the pressure-sensitive film 200 deforms to drive the second upper electrode 210 and the first lower electrode 220 to move. Furthermore, the capacitance values of the first capacitor and the second capacitor change accordingly, and the purpose of detecting pressure change is achieved based on the association between the capacitance value change and the pressure.

[0061] The upper substrate 100, the pressure-sensitive film 200, and the lower substrate 300 are all made of quartz crystal material, so that the thermal expansion coefficients of the materials of the upper substrate 100, the pressure-sensitive film 200, and the lower substrate 300 are matched, which is beneficial to reducing the packaging stress, thereby preventing the temperature drift problem. At the same time, compared with silicon material, the elastic modulus of quartz crystal material is about half of that of silicon material, and the flexibility of quartz crystal material is better. Under the same size of the pressure-sensitive film 200, the sensitivity of the pressure-sensitive film 200 made of quartz crystal material is higher. In addition, due to the higher mechanical strength, lower thermal expansion coefficient, and strong chemical stability of quartz crystal material, the area of the quartz capacitor can be made larger than that of the silicon capacitor, and the nominal capacitance value of the quartz capacitor is one order of magnitude larger than that of the silicon capacitor, which is beneficial to enhancing the anti-interference ability against stray capacitance and improving the temperature drift and time drift performance.

[0062] Next, a manufacturing method of a quartz pressure-sensitive structure provided by the present invention will be described. The manufacturing method of a quartz pressure-sensitive structure described below can be mutually corresponding and referred to with the quartz pressure-sensitive structure described above.

[0063] Reference Figures 9-14 , the present invention also provides a manufacturing method of a quartz pressure-sensitive structure, including: S100: Prepare a screen printing plate, and the screen printing plate is provided with a first alignment mark portion 710 and a paste unit 720.

[0064] S110: Prepare an upper quartz crystal wafer and a lower quartz crystal wafer. The upper quartz crystal wafer is provided with a second alignment mark portion, a first boss 130, a first upper electrode 110, and a first pad 140 connected to the first upper electrode 110. The lower quartz crystal wafer is provided with a third alignment mark portion, a second boss 330, a second lower electrode 310, and a third pad 340 connected to the second lower electrode 310.

[0065] S120: Prepare a pressure-sensitive quartz crystal wafer. The pressure-sensitive film 200 is provided with a fourth alignment mark portion, a second upper electrode 210, a first lower electrode 220, and a second pad 230 respectively connected to the second upper electrode 210 and the first lower electrode 220.

[0066] S200: Use CCD alignment. Based on the projection coincidence of the first alignment mark portion 710 and the second alignment mark portion, print the paste unit 720 of the screen printing plate onto the upper quartz crystal wafer to form a first glass paste layer. Based on the projection coincidence of the first alignment mark portion 710 and the third alignment mark portion, print the paste unit 720 of the screen printing plate onto the lower quartz crystal wafer to form a second glass paste layer.

[0067] By means of screen printing in combination with CCD alignment, the screen printing plate can accurately move the paste unit 720 onto the upper quartz crystal wafer, the pressure-sensitive quartz crystal wafer, and the lower quartz crystal wafer, enabling the glass paste in the paste unit 720 to be accurately printed at the target positions on the upper quartz crystal wafer and the lower quartz crystal wafer, and enabling the amount of the glass paste to be precisely controlled to avoid excessive overflow of the glass paste in the subsequent process. At the same time, the screen printing method can also accurately control the boundary of the glass paste, avoiding the problem of uncertain boundaries caused by the strong fluidity of the glass paste, which is beneficial to improving the uniformity and repeatability. The structure of the screen printing plate is as Figure 9 shown. The lower quartz crystal wafer and the upper quartz crystal wafer after screen printing are as Figure 10 and Figure 11 shown.

[0068] CCD alignment (Charge-Coupled Device Alignment) is a high-precision vision positioning technology based on a CCD camera. It uses the CCD camera to collect images of the target object and realizes the precise alignment of the object according to the marks in the image, namely the first alignment mark part 710, the second alignment mark part, and the third alignment mark part.

[0069] In some embodiments of the present invention, the first through hole 120 and the second through hole 320 can be formed by means of ultrasonic drilling or wet etching. In some embodiments of the present invention, the first alignment mark part 710 of the screen printing plate can include a screen printing alignment mark and a wafer-level alignment mark, and the second alignment mark part of the upper quartz crystal wafer and the alignment mark part of the lower quartz crystal wafer can include wafer-level alignment marks.

[0070] S300: Heat the upper quartz crystal wafer and the lower quartz crystal wafer according to a first preset temperature curve to cause the first glass paste layer and the second glass paste layer to degum, and cause the first glass paste layer and the second glass paste layer to be sintered by melting to form a first sintered glass paste layer and a second sintered glass paste layer.

[0071] In some embodiments of the present invention, heating can be performed using a high-temperature oven. The first preset temperature curve can be as follows: at a heating rate of 5 °C per minute, heat up to 150 °C and hold for 15 to 30 minutes to discharge the organic solvent; heat up to 200 °C and hold for 30 minutes to discharge the organic binder; heat up to 250 °C and hold for 15 to 30 minutes to activate the paste thixotropic agent; heat up to 300 °C and hold for 15 to 30 minutes to crystallize the first glass paste layer and the second glass paste layer; heat up to 350 °C and hold for 15 to 30 minutes to melt and sinter the first glass paste layer and the second glass paste layer to form the first sintered glass paste layer and the second sintered glass paste layer; after cooling to room temperature, take out the upper quartz crystal wafer and the lower quartz crystal wafer. In this way, the degumming and sintering of the glass paste are achieved.

[0072] S400: Use a alignment device to adjust the relative positions of the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer so that the projections of the third alignment mark portion and the fourth alignment mark portion coincide, and apply glue between the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer to pre-fix the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer.

[0073] S500: Use a alignment device to adjust the relative positions of the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer so that the projections of the second alignment mark portion and the fourth alignment mark portion coincide, and apply glue between the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer to pre-fix the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer.

[0074] After aligning the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer using a alignment device, use glue for pre-fixing so that the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer form a whole. Then, after aligning the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer, use glue for fixing, so that the upper quartz crystal wafer, the pressure-sensitive quartz crystal wafer, and the lower quartz crystal wafer form a whole of a three-layer structure, which is convenient for subsequent clamping and heating treatment. The pre-fixed two-layer structure and three-layer structure are as Figure 12 、 Figure 13 shown.

[0075] In some embodiments of the present invention, the glue application can be implemented using UV glue. After bonding the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer, and the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer with UV glue, it is necessary to irradiate the UV glue to cure the UV glue.

[0076] S600: Clamp and heat the pre-fixed upper quartz crystal wafer, the pressure-sensitive quartz crystal wafer, and the lower quartz crystal wafer according to the second preset temperature curve and the preset pressure curve, so that the first sintered glass paste layer forms the first glass paste bonding layer 400 to bond the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer, and the second sintered glass paste layer forms the second glass paste bonding layer 500 to bond the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer, and make the pre-fixed dispensing carbonize and decompose.

[0077] In some embodiments of the present invention, a variable-load muffle furnace can be used for clamping and heating. The second preset temperature curve and the preset pressure curve can be: apply a pre-load pressure to the upper quartz crystal wafer, the pressure-sensitive quartz crystal wafer, and the lower quartz crystal wafer of the three-layer structure. The magnitude of the pre-load pressure is 5 to 10 kg to fix the upper quartz crystal wafer, the pressure-sensitive quartz crystal wafer, and the lower quartz crystal wafer of the three-layer structure; starting from room temperature, heat up at a heating rate of 5°C per minute to 520°C, keep warm for 15 to 30 minutes, and the load pressure at the holding point is 150 to 250 kg; after the heat preservation is over, cool with the furnace. 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. During this process, the dispensing will automatically carbonize and decompose, as Figure 14 shown that the dispensing has decomposed.

[0078] S700: Perform dicing on the bonded upper quartz crystal wafer, the pressure-sensitive quartz crystal wafer, and the lower quartz crystal wafer to form the bonded upper substrate 100, the pressure-sensitive film 200, and the lower substrate 300.

[0079] S800: Fix the processing chip 600 on the upper substrate 100, and use a bonding device to connect the processing chip 600 to the first pad 140, the second pad 230, and the third pad 340 respectively through wire bonding.

[0080] After the bonding is completed, perform dicing to divide into multiple bonded upper substrates 100, pressure-sensitive films 200, and lower substrates 300. Then, add the processing chip 600 to each of the bonded upper substrates 100, pressure-sensitive films 200, and lower substrates 300. The processing chip 600 is connected to the first pad 140, the second pad 230, and the third pad 340 by 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, 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, the processing chip 600 outputs a corresponding electrical signal to achieve the effect of pressure measurement.

[0081] In some embodiments of the present invention, the processing chip 600 can be fixed on the upper substrate 100 by means of epoxy adhesive bonding. Starting from room temperature using a blast drying oven, with a heating rate of 5 °C per minute, the curing temperature: 80 - 120 °C, and the curing time: 15 - 30 minutes, to cure the epoxy adhesive, and then cooled in the furnace.

[0082] 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: 5 - 8 grams of force.

[0083] In some embodiments of the present invention, the upper quartz crystal wafer and the lower quartz crystal wafer can be made of Z-cut quartz crystal, and the second alignment mark portion and the third alignment mark portion are formed by means such as laser marking, wet etching or dry etching.

[0084] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0085] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection 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 can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0086] All actions of obtaining signals, information, or data in this application are carried out on the premise of complying with the corresponding data protection regulations and policies of the location and with the authorization given by the owner of the corresponding device.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A quartz pressure-sensitive structure, characterized in that, Comprising: An upper substrate (100) provided with a first upper electrode (110) and a first through hole (120); A pressure-sensitive film (200) provided with a second upper electrode (210) and a first lower electrode (220), the second upper electrode (210) being located on one side of the pressure-sensitive film (200), the first lower electrode (220) being located on the other side of the pressure-sensitive film (200), the pressure-sensitive film (200) being connected to the upper substrate (100) to form a first chamber communicating with the first through hole (120), the first upper electrode (110) and the second upper electrode (210) both being located in the first chamber and the first upper electrode (110) and the second upper electrode (210) being oppositely arranged; A lower substrate (300) provided with a second lower electrode (310), the lower substrate (300) being connected to the pressure-sensitive film (200) to form a second chamber, the first lower electrode (220) and the second lower electrode (310) both being located in the second chamber and the first lower electrode (220) and the second lower electrode (310) being oppositely arranged; Wherein, the upper substrate (100), the pressure-sensitive film (200) and the lower substrate (300) are all made of quartz crystal material.

2. The quartz pressure-sensitive structure according to claim 1, characterized in that, The lower substrate (300) is further provided with a second through hole (320) communicating with the second chamber.

3. A quartz pressure-sensitive structure according to claim 1 or 2, characterized in that, A first glass paste bonding layer (400) is provided between the upper substrate (100) and the pressure-sensitive film (200), the first glass paste bonding layer (400) being connected to the upper substrate (100) and the pressure-sensitive film (200) respectively to form the first chamber, and the thermal expansion coefficient of the first glass paste bonding layer (400) matching the thermal expansion coefficient of the upper substrate (100) and the thermal expansion coefficient of the pressure-sensitive film (200) respectively.

4. The quartz pressure-sensitive structure according to claim 3, characterized in that, The upper substrate (100) is provided with at least one first boss (130), and the first boss (130) is used for abutting against the pressure-sensitive film (200) to control the thickness of the first glass paste bonding layer (400).

5. A quartz pressure-sensitive structure according to claim 1 or 2, characterized in that, A second glass paste bonding layer (500) is provided between the lower substrate (300) and the pressure-sensitive film (200), the second glass paste bonding layer (500) being connected to the lower substrate (300) and the pressure-sensitive film (200) respectively to form the second chamber, and the thermal expansion coefficient of the second glass paste bonding layer (500) matching the thermal expansion coefficient of the upper substrate (100) and the thermal expansion coefficient of the pressure-sensitive film (200) respectively.

6. A quartz pressure-sensitive structure according to claim 5, characterized in that, At least one second boss (330) is provided on the lower substrate (300), and the second boss (330) is used for abutting against the pressure-sensitive film (200) to control the thickness of the second glass paste bonding layer (500).

7. A quartz pressure-sensitive structure according to claim 1, characterized in that, It further includes a processing chip (600), the processing chip (600) is disposed 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 (230) connected to the second upper electrode (210) and the first lower electrode (220), the lower substrate (300) is provided with a third pad (340) connected to the second lower electrode (310), and the processing chip (600) is respectively connected to the first pad (140), the second pad (230) and the third pad (340).

8. A quartz pressure-sensitive structure according to claim 7, characterized in that, The processing chip (600) is respectively connected to the first pad (140), the second pad (230) and the third pad (340) through bonding wires. The third pad (340) is located at the edge of the lower substrate (300). A first connection opening (150) corresponding to the third pad (340) is provided at the edge of the pressure-sensitive film (200). The second pad (230) is located at the edge of the pressure-sensitive film (200). A second connection opening (240) corresponding to the second pad (230) is provided at the edge of the upper substrate (100). The first connection opening (150) and the second connection opening (240) are used for the bonding wires to pass through.

9. A pressure sensor, characterized in that, It includes: a sensor housing and a quartz pressure-sensitive structure as described in any one of claims 1 to 8 disposed in the sensor housing. The sensor housing is provided with a first detection end, and the first detection end is communicated with the first through hole (120).

10. A manufacturing method of a quartz pressure-sensitive structure, characterized in that, Applied to a quartz pressure-sensitive structure as described in any one of claims 1 to 8, it includes: Preparing a screen printing plate, the screen printing plate is provided with a first alignment mark portion (710) and a paste unit (720); Preparing an upper quartz crystal wafer and a lower quartz crystal wafer. The upper quartz crystal wafer is provided with a second alignment mark portion, a first boss (130), a first upper electrode (110) and a first pad (140) connected to the first upper electrode (110). The lower quartz crystal wafer is provided with a third alignment mark portion, a second boss (330), a second lower electrode (310) and a third pad (340) connected to the second lower electrode (310); Preparing a pressure-sensitive quartz crystal wafer. The pressure-sensitive film (200) is provided with a fourth alignment mark portion, a second upper electrode (210), a first lower electrode (220) and a second pad (230) respectively connected to the second upper electrode (210) and the first lower electrode (220); Using CCD alignment, based on the projection coincidence of the first alignment mark part (710) and the second alignment mark part, print the paste unit (720) of the screen printing plate onto the upper quartz crystal wafer to form a first glass paste layer, and based on the projection coincidence of the first alignment mark part (710) and the third alignment mark part, print the paste unit (720) of the screen printing plate onto the lower quartz crystal wafer to form a second glass paste layer; Heat the upper quartz crystal wafer and the lower quartz crystal wafer according to a first preset temperature curve to cause degumming of the first glass paste layer and the second glass paste layer, and cause the first glass paste layer and the second glass paste layer to melt and sinter to form a first sintered glass paste layer and a second sintered glass paste layer; Using an alignment device, adjust the relative position of the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer so that the projection of the third alignment mark part coincides with the projection of the fourth alignment mark part, and apply glue between the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer to pre-fix the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer; Using an alignment device, adjust the relative position of the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer so that the projection of the second alignment mark part coincides with the projection of the fourth alignment mark part, and apply glue between the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer to pre-fix the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer; Clamp and heat the pre-fixed upper quartz crystal wafer, the pressure-sensitive quartz crystal wafer, and the lower quartz crystal wafer according to a second preset temperature curve and a preset pressure curve, cause the first sintered glass paste layer to form a first glass paste bonding layer (400) to bond the upper quartz crystal wafer and the pressure-sensitive quartz crystal wafer, cause the second sintered glass paste layer to form a second glass paste bonding layer (500) to bond the lower quartz crystal wafer and the pressure-sensitive quartz crystal wafer, and cause the pre-fixed glue to carbonize and decompose; Perform dicing on the bonded upper quartz crystal wafer, the pressure-sensitive quartz crystal wafer, and the lower quartz crystal wafer to form a bonded upper substrate (100), a pressure-sensitive film (200), and a lower substrate (300); Fix the processing chip (600) on the upper substrate (100), and use a bonding device to connect the processing chip (600) to the first pad (140), the second pad (230), and the third pad (340) respectively through wire bonding.

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