Intelligent wideband five-wire oxygen sensor chip and manufacturing method therefor

Abstract

Disclosed in the present invention are an intelligent wideband five-wire oxygen sensor chip and a manufacturing method therefor. Said chip comprises base body layers, an outer electrode, a reference electrode, pump electrodes, a pump electrode diffusion barrier and a heater layer. The pump electrode diffusion barrier is printed in a third base body layer, used for control and adjustment for diffusion of oxygen in an oxygen pump chamber. The present invention uses the mode of double-side-face intake to replace the traditional modes of using a top small hole and multiple holes for intake, thus effectively solving the problem in the prior art of difficulty in accurately determining the position in small hole machining.

Description

An intelligent wide-range five-wire oxygen sensor chip and its manufacturing method Technical Field

[0001] The present invention relates to the field of oxygen sensor chips, and in particular to an intelligent wide-range five-wire oxygen sensor chip and a manufacturing method thereof. Background Art

[0002] The oxygen sensor is an indispensable component in the electronic fuel injection engine control system. It is a key component for controlling automobile exhaust emissions, reducing automobile pollution to the environment, and improving automobile engine combustion quality.

[0003] Among them, the lean burn technology of the oxygen sensor can improve fuel efficiency and reduce the emission of exhaust pollutants, but lean burn can easily cause the engine to stall, and unreasonable mixing will produce excessive NOx compounds, leading to environmental pollution. The wide-range oxygen sensor can accurately monitor the accurate oxygen content in the entire range of automobile exhaust to reflect the engine operating status. Only then can the engine computer make adjustments based on its real-time status, thereby improving combustion efficiency, reducing pollution emissions and detecting the operating status of the three-way catalytic converter.

[0004] The core component of a five-line wide-bandwidth oxygen sensor is the chip. This chip is constructed by laminating four layers of dense zirconia substrates with a multilayer printed circuit board, consisting of a heater electrode, an outer electrode, a reference electrode, a pump electrode mixing chamber, a pump electrode diffusion barrier, and a pump electrode bottom. Currently, the pump electrode diffusion barrier of a five-line wide-bandwidth oxygen sensor chip uses small holes for air intake, but this intake method has several drawbacks.

[0005] First, the drilling depth and precision cannot be accurately controlled, and it is difficult to ensure data consistency in the production process.

[0006] Secondly, in the pinhole intake method, gas enters the pump electrode diffusion barrier through the small hole, which generates a certain amount of resistance. Since the gas pressure and flow rate may vary, the resistance of the pinhole intake method will also change accordingly. This may affect the response speed and stability of the oxygen sensor.

[0007] Secondly, in the pinhole intake method, gas enters the pump electrode diffusion barrier through the small hole, which generates a certain amount of resistance. Since the gas pressure and flow rate may vary, the resistance of the pinhole intake method will also change accordingly. This may affect the response speed and stability of the oxygen sensor.

[0008] Finally, the small diameter of the pinhole inlet method makes it susceptible to clogging by tiny particles in the gas. This can prevent the gas from properly entering the pump electrode through the diffusion barrier, affecting the oxygen sensor's performance. Furthermore, if harmful substances are present in the gas, the pinhole can easily become contaminated, affecting the sensor's accuracy. Summary of the Invention

[0009] In response to the above technical problems, the present invention provides an intelligent wide-band five-wire oxygen sensor chip, which is characterized by comprising:

[0010] A base layer, wherein the base layer has a four-layer structure, including, from bottom to top, a first base layer, a second base layer, a third base layer, and a fourth base layer;

[0011] an outer electrode, disposed above the fourth substrate layer and configured to contact oxygen to measure oxygen concentration;

[0012] a reference electrode, disposed below the third substrate layer, configured to receive electrons from oxygen and interact with the electrolyte between the outer electrodes to form a current;

[0013] a pump electrode, the pump electrode comprising an upper pump electrode and a lower pump electrode, a pump electrode mixing cavity being provided between the upper pump electrode and the lower pump electrode, the pump electrode mixing cavity penetrating both sides of the third base layer, and having a width the same as that of the third base layer;

[0014] a pump electrode diffusion barrier, the pump electrode diffusion barrier being arranged below the pump electrode mixing chamber;

[0015] and a heater layer disposed between the first substrate layer and the second substrate layer;

[0016] and a heater layer disposed between the first substrate layer and the second substrate layer;

[0017] The pump electrode diffusion barrier is printed inside the third base layer to control and regulate the diffusion of oxygen in the pump oxygen cavity.

[0018] In the prior art, the pump electrode diffusion barrier is mostly protruding from the surface of the substrate layer, and the pump electrode mixing chamber takes in air from the small holes on the top or multiple holes, and then transports air to the pump electrode diffusion barrier. The present invention sets the pump electrode diffusion barrier inside the third substrate layer and adopts a structure of four pump electrode diffusion barriers on both sides. Specifically, a certain width and depth of pits are pressed out inside the third substrate layer, and then the diffusion layer printing paste is filled into the pits to form four pump electrode diffusion barriers. On the one hand, the structure of the present invention realizes air intake from both sides, without the need for air intake through the small holes on the top, and also does not require small hole drilling during processing, avoiding the problem of inaccurate control of drilling depth and precision affecting the sensitivity of the sensor chip, and to a certain extent avoiding the problem of response drift after long-term use caused by the traditional multi-hole air intake method; on the other hand, the structure of the double-sided pump electrode diffusion barrier of the present invention can form an effective support to prevent the pump electrode mixing chamber from collapsing and closing caused by warm isostatic pressing and high-temperature sintering during processing, thereby ensuring that the mixing chamber does not deform.

[0019] Preferably, a surface insulation layer is provided below the first base layer, an end lead is provided below the surface insulation, a heater lower insulation is provided below the heater layer, and a heater through hole is provided on the first base layer, and the position of the through hole is opposite to the end lead and the heater lower insulation.

[0020] Preferably, an air channel and an upper insulating layer of the heater are provided below the second base layer.

[0021] Preferably, a reference electrode upper insulation is provided below the third base layer, a reference electrode via hole is provided on the third base layer, and the reference electrode via hole is located on one side of the third base layer, facing the reference electrode.

[0022] Preferably, a pump electrode upper insulator is provided below the fourth base layer, a pump electrode lower insulator is provided below the upper pump electrode, and an electrode via hole is provided on the upper surface of the fourth base layer. The electrode via hole, the reference electrode via hole, and the heater via hole are all filled with a filling material to form the electrode via hole, the reference electrode via hole, and the heater via hole, respectively.

[0023] Preferably, an outer electrode lower insulation is provided below the outer electrode, an end lead is provided above the outer electrode, and a protective layer is provided above the end lead.

[0024] Preferably, a layer of tetracobalt trioxide ultra-thin nanostructure is provided on the surface of the base layer.

[0025] The present invention utilizes a hydrothermal chemical deposition method to deposit an ultrathin nanofilm of tetracobalt trioxide on the surface of a substrate layer, and utilizes an anionic surfactant, sodium dodecylbenzenesulfonate, to promote the formation of the tetracobalt trioxide nanofilm. Compared to the zirconium oxide base plate in the prior art, the addition of the ultrathin tetracobalt trioxide nanofilm enables the zirconium oxide diaphragm to obtain better electrocatalytic activity and achieve faster electron transfer dynamics, as well as a high specific surface area and excellent response detection effect. Tetracobalt trioxide is a p-type magnetic semiconductor material with a spinel structure. It is also an ionic semiconductor with diverse polarity sites, which helps the oxygen sensor chip detect charge more sensitively.

[0026] Since the present invention adopts a new air intake method, namely the two-side air intake mentioned above, which changes the traditional porous and small hole methods, it is necessary to consider the changes in resistance and detection sensitivity caused by the change in gas entry method. Therefore, it is necessary to start from the improvement of the substrate layer and improve the overall performance, so as to cooperate to obtain better sensor detection effects.

[0027] The present invention also provides a method for manufacturing an intelligent wide-band five-wire oxygen sensor chip, comprising the following steps:

[0028] S1, preparing zirconium oxide casting slurry and printing slurry, wherein the printing slurry includes a protective layer printing slurry, an insulating layer printing slurry, an electrode layer printing slurry, a diffusion layer printing slurry and an airway printing slurry;

[0029] S2, using an automatic tape casting machine to press the zirconium oxide casting slurry into a zirconium oxide membrane, ultrasonically cleaning and drying the zirconium oxide membrane, evaporating and adsorbing a 10-15 nm titanium adhesive layer on the dried zirconium oxide membrane in a vacuum evaporation chamber, soaking the zirconium oxide membrane in urea, cobalt chloride, and anionic surfactant for 2 hours, washing with deionized water, and drying to obtain a zirconium oxide membrane with a layer of cobalt hydroxide nanostructures on the surface;

[0030] S3, stacking the zirconium oxide diaphragms into diaphragms of desired thickness using a laminating machine, followed by hot pressing and drying;

[0031] S4, punching the dried zirconia diaphragm to form electrode via holes, reference electrode via holes, and heater via holes;

[0032] S5, using printing paste to print the punched diaphragm, printing on the first base layer, the second base layer, the third base layer and the fourth base layer, printing the protective layer with the printing paste, printing the outer electrode lower insulation, the pump electrode lower insulation, the pump electrode upper insulation, the reference electrode upper insulation, the reference electrode lower insulation, the heater upper insulation, the heater lower insulation and the surface insulation with the printing paste, printing the outer electrode, the terminal lead, the upper pump electrode, the lower pump electrode, the reference electrode and the heater layer with the printing paste, printing the pump electrode mixing cavity and the pump electrode diffusion barrier with the printing paste, and printing the airway with the printing paste;

[0033] S6, stacking the dried zirconia diaphragm in the order of a first substrate layer, a second substrate layer, a third substrate layer, and a fourth substrate layer from bottom to top, vacuum packaging the laminated diaphragm, and then performing warm isostatic pressing at a temperature of 50° C. and a time of 20 minutes.

[0034] S7, chamfering and cutting the formed diaphragm, and thus the preliminary model of the oxygen sensor chip has been produced;

[0035] S8, sending the preliminarily formed chip into a sintering furnace for sintering at a temperature of 1450°C. The cobalt hydroxide nanostructure on the surface of the zirconia membrane is converted into a tetracobalt trioxide nanofilm. The chip is now completely formed.

[0036] S9, testing the fully formed chip, including chip curvature test, sensor leakage test, strength test and electrical performance test, and the electrical performance test also includes heater resistance test, insulation resistance test and current test.

[0037] In addition, the present invention can also adsorb a polymer film containing polyvinyl chloride, β-cyclodextrin, and potassium tetrachlorophenylborate on the nanofilm, which can reduce the impact of water droplets in the gas on the sensitivity of the oxygen sensor chip when monitoring the oxygen content in the exhaust gas. This requires adding a 450°C annealing process at the end of the above-mentioned S2 step of the present invention. In this step, a cobalt trioxide film is first generated and then immersed in a film solution of polyvinyl chloride, β-cyclodextrin, and potassium tetrachlorophenylborate multiple times to form a polymer film to ensure the detection sensitivity of the chip in a humid environment.

[0038] Preferably, the zirconia casting slurry comprises 50-60% of 5 mol yttria-stabilized zirconia casting powder, 2-5% of a dispersant, 10-15% of an organic solvent, 20-25% of a binder and 15-20% of an adhesive;

[0039] The protective layer printing paste includes 25-30% alumina powder, 25-30% activated carbon powder, 2-5% binder, 30-35% organic solvent, 2-5% plasticizer and 1-3% dispersant;

[0040] The insulating layer printing paste includes 45-55% nano-alumina powder, 2-5% binder, 30-40% organic solvent, 2-5% plasticizer and 2-5% dispersant;

[0041] The electrode layer printing paste includes 65-75% platinum powder, 3-8% oxide, 2-5% binder and 10-20% organic solvent;

[0042] The diffusion layer printing paste includes 40-50% zirconium oxide powder, 10-20% activated carbon powder, 2-5% binder, 25-35% organic solvent, 2-5% plasticizer and 1-3% dispersant;

[0043] The airway printing paste includes 20-30% activated carbon powder, 20-30% zirconium oxide powder, 2-5% binder, 40-50% organic solvent and 1-3% dispersant. Beneficial effects

[0044] 1. The present invention adopts a double-side air intake method to replace the traditional top small hole and multi-hole air intake, effectively overcoming the problem of difficult to accurately locate the position of small hole processing in the existing technology.

[0045] 2. The present invention uses a zirconium oxide diaphragm coated with a cobalt trioxide nanofilm as a base layer, which has better response effect and detection sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present invention will be further described below with reference to the accompanying drawings.

[0047] FIG1 is a schematic structural diagram of a first embodiment of the present invention;

[0048] FIG2 is a schematic structural diagram of a second embodiment of the present invention.

[0049] The numbers in the figure represent:

[0050] 1. Protective layer, 2. External electrode, 3. Insulation under the external electrode, 4. Insulation on the pump electrode, 5. Upper pump electrode, 6. Pump electrode mixing chamber, 7. Pump electrode diffusion barrier, 8. Lower pump electrode, 9. Third substrate layer, 10. Reference electrode, 11. Air channel, 12. Second substrate layer, 13. Heater layer, 14. First substrate layer, 15. End lead, 16. Electrode conductive filling hole, 17. Fourth substrate layer, 18. Insulation under the pump electrode, 19. Reference electrode conductive filling hole, 20. Insulation on the reference electrode, 21. Insulation under the reference electrode, 22. Insulation on the heater, 23. Heater conductive filling hole, 24. Insulation under the heater, 25. Surface insulation, 26. End insulation, 27. Inner electrode, 28. Pump oxygen chamber. DETAILED DESCRIPTION

[0051] Various aspects of the present invention are described in further detail below.

[0052] Unless otherwise defined or indicated, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein can be applied to the methods of the present invention.

[0053] As shown in FIG1 , the present invention provides an intelligent wide-band five-wire oxygen sensor chip as embodiment 1, which mainly includes:

[0054] The base layer has a four-layer structure, including, from bottom to top, a first base layer 14, a second base layer 12, a third base layer 9, and a fourth base layer 17;

[0055] an external electrode 2, the external electrode 2 being disposed above the fourth base layer 17 and configured to contact oxygen to measure oxygen concentration;

[0056] A reference electrode 10 is provided below the third substrate layer 9 and is used to receive electrons from oxygen and interact with the electrolyte between the outer electrode 2 to form a current;

[0057] Pump electrodes, the pump electrodes comprising an upper pump electrode 5 and a lower pump electrode 8, a pump electrode mixing cavity 6 being provided between the upper pump electrode 5 and the lower pump electrode 8, the pump electrode mixing cavity 6 passing through both sides of the third base layer 9, and having the same width as that of the third base layer 9;

[0058] a pump electrode diffusion barrier 7, wherein the pump electrode diffusion barrier 7 is provided below the pump electrode mixing chamber 6;

[0059] and a heater layer 13, wherein the heater layer 13 is provided between the first base layer 14 and the second base layer 12;

[0060] The pump electrode diffusion barrier 7 is printed inside the third base layer 9 to control and regulate the diffusion of oxygen in the oxygen pump cavity 28 .

[0061] In the prior art, the pump electrode diffusion barrier 7 is often protruding from the surface of the substrate layer, and the pump electrode mixing chamber 6 is supplied with air through a small hole or multiple holes at the top, and then transported to the pump electrode diffusion barrier 7. The present invention disposes the pump electrode diffusion barrier 7 inside the third substrate layer 9 and adopts a structure with four pump electrode diffusion barriers 7 on both sides. Specifically, a depression of a certain width and depth is pressed into the third substrate layer 9, and the diffusion layer printing paste is then filled into the depression to form four pump electrode diffusion barriers 7. On the one hand, the structure of the present invention realizes air intake from both sides, eliminating the need for air intake through the small holes at the top, and thus eliminating the need for drilling during processing. This avoids the problem of inaccurate drilling depth and precision control affecting the sensitivity of the sensor chip, and to a certain extent avoids the problem of response drift after long-term use caused by traditional multi-hole air intake methods. On the other hand, the structure of the double-sided pump electrode diffusion barrier 7 of the present invention can provide effective support, preventing the pump electrode mixing chamber 6 from collapsing and closing due to warm isostatic pressing and high-temperature sintering during processing, ensuring that the mixing chamber does not deform.

[0062] A surface insulation layer 25 is provided below the first base layer 14, an end lead 15 is provided below the surface insulation 25, a heater lower insulation 24 is provided below the heater layer 13, and a heater through hole is provided on the first base layer 14, and the position of the through hole is opposite to the end lead 15 and the heater lower insulation 24.

[0063] An air channel 11 and a heater upper insulation 22 are provided below the second base layer 12 .

[0064] A reference electrode upper insulator 20 is provided below the third base layer 9 , and a reference electrode 10 conducting hole is provided on the third base layer 9 . The reference electrode 10 conducting hole is located on one side of the third base layer 9 and faces the reference electrode 10 .

[0065] A pump electrode upper insulator 4 is provided below the fourth base layer 17, a pump electrode lower insulator 18 is provided below the upper pump electrode 5, and electrode vias are provided on the upper surface of the fourth base layer 17. The electrode vias, the reference electrode 10 vias, and the heater vias are all filled with a filling material to form electrode vias 16, reference electrode vias 19, and heater vias 23, respectively.

[0066] A pump electrode upper insulator 4 is provided below the fourth base layer 17, a pump electrode lower insulator 18 is provided below the upper pump electrode 5, and electrode vias are provided on the upper surface of the fourth base layer 17. The electrode vias, the reference electrode 10 vias, and the heater vias are all filled with a filling material to form electrode vias 16, reference electrode vias 19, and heater vias 23, respectively.

[0067] An outer electrode lower insulation 3 is provided below the outer electrode 2 , a terminal lead 15 is provided above the outer electrode 2 , and a protective layer 1 is provided above the terminal lead 15 .

[0068] A layer of tetracobalt trioxide ultra-thin nanostructure is provided on the surface of the base layer.

[0069] The present invention utilizes a hydrothermal chemical deposition method to deposit an ultrathin nanofilm of tetracobalt trioxide on the surface of a substrate layer, and utilizes an anionic surfactant, sodium dodecylbenzenesulfonate, to promote the formation of the tetracobalt trioxide nanofilm. Compared to the zirconium oxide base plate in the prior art, the addition of the ultrathin tetracobalt trioxide nanofilm enables the zirconium oxide diaphragm to obtain better electrocatalytic activity and achieve faster electron transfer dynamics, as well as a high specific surface area and excellent response detection effect. Tetracobalt trioxide is a p-type magnetic semiconductor material with a spinel structure. It is also an ionic semiconductor with diverse polarity sites, which helps the oxygen sensor chip detect charge more sensitively.

[0070] Since the present invention adopts a new air intake method, namely the two-side air intake mentioned above, which changes the traditional porous and small hole methods, it is necessary to consider the changes in resistance and detection sensitivity caused by the change in gas entry method. Therefore, it is necessary to start from the improvement of the substrate layer and improve the overall performance, so as to cooperate to obtain better sensor detection effects.

[0071] The present invention utilizes a hydrothermal chemical deposition method to deposit an ultrathin nanofilm of tetracobalt trioxide on the surface of a substrate layer, and utilizes an anionic surfactant, sodium dodecylbenzenesulfonate, to promote the formation of the tetracobalt trioxide nanofilm. Compared to the zirconium oxide base plate in the prior art, the addition of the ultrathin tetracobalt trioxide nanofilm enables the zirconium oxide diaphragm to obtain better electrocatalytic activity and achieve faster electron transfer dynamics, as well as a high specific surface area and excellent response detection effect. Tetracobalt trioxide is a p-type magnetic semiconductor material with a spinel structure. It is also an ionic semiconductor with diverse polarity sites, which helps the oxygen sensor chip detect charge more sensitively.

[0072] Since the present invention adopts a new air intake method, namely the two-side air intake mentioned above, which changes the traditional porous and small hole methods, it is necessary to consider the changes in resistance and detection sensitivity caused by the change in gas entry method. Therefore, it is necessary to start from the improvement of the substrate layer and improve the overall performance, so as to cooperate to obtain better sensor detection effects.

[0073] The present invention also provides a method for manufacturing an intelligent wide-band five-wire oxygen sensor chip, comprising the following steps:

[0074] S1, preparing zirconium oxide casting slurry and printing slurry, wherein the printing slurry includes protective layer 1 printing slurry, insulating layer printing slurry, electrode layer printing slurry, diffusion layer printing slurry and air channel 11 printing slurry;

[0075] S2, using an automatic tape casting machine to press the zirconium oxide casting slurry into a zirconium oxide membrane, ultrasonically cleaning and drying the zirconium oxide membrane, evaporating and adsorbing a 10-15 nm titanium adhesive layer on the dried zirconium oxide membrane in a vacuum evaporation chamber, soaking the zirconium oxide membrane in urea, cobalt chloride, and anionic surfactant for 2 hours, washing with deionized water, and drying to obtain a zirconium oxide membrane with a layer of cobalt hydroxide nanostructures on the surface;

[0076] S3, stacking the zirconium oxide diaphragms into diaphragms of desired thickness using a laminating machine, followed by hot pressing and drying;

[0077] S4, punching the dried zirconium oxide diaphragm to form electrode via holes, reference electrode 10 via holes, and heater via holes;

[0078] S5, using printing paste to print the punched diaphragm, printing is performed on the first base layer 14, the second base layer 12, the third base layer 9 and the fourth base layer 17, the protective layer 1 printing paste is used to print the protective layer 1, the insulating layer printing paste is used to print the outer electrode lower insulation 3, the pump electrode lower insulation 18, the pump electrode upper insulation 4, the reference electrode upper insulation 20, the reference electrode lower insulation 21, the heater upper insulation 22, the heater lower insulation 24 and the surface insulation 25, the electrode layer printing paste is used to print the outer electrode 2, the terminal lead 15, the upper pump electrode 5, the lower pump electrode 8, the reference electrode 10 and the heater layer 13, the diffusion layer printing paste is used to print the pump electrode mixing cavity 6 and the pump electrode diffusion barrier 7, and the airway 11 printing paste is used to print the airway 11;

[0079] S6, laminating the dried zirconia diaphragm in the order of the first base layer 14, the second base layer 12, the third base layer 9, and the fourth base layer 17 from bottom to top, vacuum packaging, and then performing warm isostatic pressing at a temperature of 50° C. and a time of 20 minutes.

[0080] S7, chamfering and cutting the formed diaphragm, and thus the preliminary model of the oxygen sensor chip has been produced;

[0081] S8, sending the preliminarily formed chip into a sintering furnace for sintering at a temperature of 1450°C. The cobalt hydroxide nanostructure on the surface of the zirconia membrane is converted into a tetracobalt trioxide nanofilm. The chip is now completely formed.

[0082] S9, testing the fully formed chip, including chip curvature test, sensor leakage test, strength test and electrical performance test, and the electrical performance test also includes heater resistance test, insulation resistance test and current test.

[0083] Furthermore, the present invention can also adsorb a polymer film containing polyvinyl chloride, β-cyclodextrin, and potassium tetrachlorophenylborate onto the nanofilm, which can reduce the impact of water droplets in the gas on the sensitivity of the oxygen sensor chip when monitoring the oxygen content in exhaust gas. This requires adding a 450°C annealing step at the end of step S2. In this step, a cobalt trioxide film is first formed and then repeatedly immersed in a film solution of polyvinyl chloride, β-cyclodextrin, and potassium tetrachlorophenylborate to form a polymer film, ensuring the chip's detection sensitivity in humid environments. To verify the technical benefits of the cobalt trioxide ultra-thin nanostructure on the substrate layer of the present invention compared to the substrate layer of the prior art, the LOD (limit of detection) values ​​of the processed oxygen sensor chip were tested. The results showed that the oxygen sensor chip of the present invention has a lower LOD value and does not exhibit linear deviation even at low oxygen concentrations in the detection gas. Compared with existing wide-band five-line oxygen sensor chips, the present invention has a lower LOD value, a wider detection range, and superior detection sensitivity.

[0084] The zirconia casting slurry comprises 50-60% of 5 mol yttria-stabilized zirconia casting powder, 2-5% of a dispersant, 10-15% of an organic solvent, 20-25% of a binder, and 15-20% of an adhesive;

[0085] The printing paste of the protective layer 1 includes 25-30% alumina powder, 25-30% activated carbon powder, 2-5% binder, 30-35% organic solvent, 2-5% plasticizer and 1-3% dispersant;

[0086] The insulating layer printing paste includes 45-55% nano-alumina powder, 2-5% binder, 30-40% organic solvent, 2-5% plasticizer and 2-5% dispersant;

[0087] The electrode layer printing paste includes 65-75% platinum powder, 3-8% oxide, 2-5% binder and 10-20% organic solvent;

[0088] The diffusion layer printing paste includes 40-50% zirconium oxide powder, 10-20% activated carbon powder, 2-5% binder, 25-35% organic solvent, 2-5% plasticizer and 1-3% dispersant;

[0089] The printing paste of the air channel 11 includes 20-30% of activated carbon powder, 20-30% of zirconium oxide powder, 2-5% of binder, 40-50% of organic solvent and 1-3% of dispersant.

[0090] In addition to the dual-cell wide-range oxygen sensor chip with a reference electrode 10, the present invention also includes another single-cell wide-range oxygen sensor chip as shown in Figure 2, which is used as the second embodiment of the present invention. It includes, from bottom to top: an end lead 15, an end insulation 26, a first substrate layer 14, a heater lower insulation 24, a heater layer 13, a heater upper insulation 22, a second substrate layer 12, an air channel 11 provided on the second substrate layer 12, an inner electrode 27, a third substrate layer 9, a lower pump electrode 8, an oxygen pumping cavity 28, an upper pump electrode 5, a fourth substrate layer 17, an end insulation 26, an outer electrode 2 and a protective layer 1.

[0091] The manufacturing method of this single-cell oxygen sensor chip is the same as that of the previous embodiment. It also has a four-layer base layer. During the manufacturing process, a 60-80 micron thick membrane is cast by steel strip casting. The membrane is then stacked to a certain thickness and then hot-pressed at 65°C to form a 0.4mm thick base membrane. Then, each functional layer is printed with a slurry of the same formula and stacked in sequence. Specifically, a platinum outer electrode 2 is printed on the fourth base layer 17, a protective layer 1 is printed on the outer electrode 2, and a 0.4mm thick base membrane is formed. The terminal insulation 26 is printed under the electrode 2, the upper pump electrode 5 is printed under the fourth base layer 17, the lower pump electrode 8 and the oxygen pump cavity 28 are printed on the third base layer 9, the inner electrode 27 is printed under the third base layer 9, the air channel 11 is printed on the second base layer 12, the heater upper insulation 22 is printed under the second base layer 12, the heater layer 13 and the heater lower insulation 24 are printed on the first base layer 14, and the terminal insulation 26 and the terminal lead 15 are printed under the first base layer 14. The four printed diaphragms are stacked, heated, and cut in sequence to form a single five-wire chip. The chip is then sintered at a high temperature of 1450 degrees for 2 hours according to the sintering curve through debinding sintering.

[0092] After processing, both embodiments of the present invention need to be tested. The test items include: chip curvature test, sensor leakage test, strength test and electrical performance test, among which the electrical performance test also includes heater resistance test, insulation resistance test and current test.

[0093] Chip curvature test: Randomly select 100 chips and place them flat on a high-flatness workbench. Use a feeler gauge to measure three points at the head, middle, and tail of the sensor. The test thickness is less than 0.1mm.

[0094] Sensor leakage test: 100 chips were randomly selected and assembled, and their leakage rate was tested using a leak tester. A pressure of 3.6±0.1 bar was applied to the air reference channel of the sensor, and the leakage rate was less than 0.43 ml / min.

[0095] Strength test: 10 chips were taken for three-point bending strength test. The bending strength of the oxygen sensor was >50Mpa.

[0096] Electrical performance test:

[0097] Heater resistance test: Randomly select 100 chips and use a multimeter to test the room temperature resistance of their heating electrodes through the heating pins. The resistance is within the range of 3±1ohm.

[0098] Insulation resistance test: Randomly select 100 chips and use an insulation tester to test the insulation resistance of the heater to the signal external electrode 2 end, the insulation resistance of the heater to the reference electrode 10 end, and the insulation resistance of the signal external electrode 2 end to the reference electrode 10 end. The insulation resistance should be ≥ 10MΩ.

[0099] Current test: After 100 chips were randomly selected and assembled into finished products, their current in air was measured using a wide-band detection device. The input voltage was 8-10V and the pump current was 1.3-6mA.

[0100] The five-line wide-band oxygen sensor chips in the present invention all adopt a structure with air intake on both sides. The special pump electrode air intake method and manufacturing method can be used for the production and manufacturing of five-line wide-band oxygen sensor chips of various product types. The internal resistance and pump electrode size can be adjusted according to the product type. For example, the porosity of the pump electrode diffusion barrier 7 can be fine-tuned to change the size of the pump electrode, etc. Such adjustments fall within the scope of protection of the present invention.

[0101] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. An intelligent wide-range five-wire oxygen sensor chip, characterized in that: include: A substrate layer, wherein the substrate layer has a four-layer structure, and comprises, from bottom to top, a first substrate layer, a second substrate layer, a third substrate layer and a fourth substrate layer; an outer electrode, the outer electrode being disposed above the fourth substrate layer and being used for contacting with oxygen to measure oxygen concentration; A reference electrode, the reference electrode being disposed below the third substrate layer; A pump electrode, wherein the pump electrode comprises an upper pump electrode and a lower pump electrode, a pump electrode mixing cavity is provided between the upper pump electrode and the lower pump electrode, the pump electrode mixing cavity passes through both sides of the third substrate layer, and the width thereof is the same as the width of the third substrate layer; A pump electrode diffusion barrier, wherein the pump electrode diffusion barrier is disposed below the pump electrode mixing chamber; and a heater layer disposed between the first substrate layer and the second substrate layer; The pump electrode diffusion barrier is printed inside the third substrate layer to control and regulate the diffusion of oxygen in the pump oxygen cavity; a layer of tetracobalt trioxide ultra-thin nanostructure converted from cobalt hydroxide nanostructure is provided on the surface of the substrate layer.

2. The intelligent wide-range five-wire oxygen sensor chip according to claim 1, characterized in that: A surface insulation layer is provided below the first substrate layer, a terminal lead is provided below the surface insulation, a heater lower insulation is provided below the heater layer, and a heater through hole is provided on the first substrate layer, and the position of the through hole is opposite to the terminal lead and the heater lower insulation.

3. The intelligent wide-range five-wire oxygen sensor chip according to claim 2, characterized in that: An air channel and an upper insulating layer of the heater are arranged below the second substrate layer.

4. The intelligent wide-range five-wire oxygen sensor chip according to claim 3, characterized in that: A reference electrode upper insulator is provided below the third substrate layer, and a reference electrode conducting hole is provided on the third substrate layer. The reference electrode conducting hole is located at one side of the third substrate layer and faces the reference electrode.

5. The intelligent wide-range five-wire oxygen sensor chip according to claim 4, characterized in that: A pump electrode upper insulation is provided below the fourth substrate layer, a pump electrode lower insulation is provided below the upper pump electrode, and an electrode conductive hole is provided on the upper surface of the fourth substrate layer. The electrode conductive hole, the reference electrode conductive hole and the heater conductive hole are all filled with a filling material to form an electrode conductive filled hole, a reference electrode conductive filled hole and a heater conductive filled hole, respectively.

6. The intelligent wide-range five-wire oxygen sensor chip according to claim 5, characterized in that: An outer electrode lower insulation is provided below the outer electrode, a terminal lead is provided above the outer electrode, and a protective layer is provided above the terminal lead.

7. A method for manufacturing an intelligent wide-band five-wire oxygen sensor chip as claimed in claim 6, characterized in that the steps include: S1, preparing zirconium oxide casting slurry and printing slurry, wherein the printing slurry includes a protective layer printing slurry, an insulating layer printing slurry, an electrode layer printing slurry, a diffusion layer printing slurry and an airway printing slurry; S2, using an automatic casting machine to press the zirconium oxide casting slurry into a zirconium oxide diaphragm, ultrasonically cleaning and drying the zirconium oxide diaphragm, evaporating and adsorbing a 10-15 nm titanium adhesive layer on the dried zirconium oxide diaphragm in a vacuum evaporation chamber, soaking the zirconium oxide diaphragm in urea, cobalt chloride and anionic surfactant for 2 hours, washing with deionized water and drying, to obtain a zirconium oxide diaphragm with a layer of cobalt hydroxide nanostructure on the surface; S3, stacking the zirconium oxide diaphragms into diaphragms of required thickness by a stacking machine, and then hot pressing and drying; S4, punching the dried zirconium oxide diaphragm to form electrode via holes, reference electrode via holes, and heater via holes; S5, using printing paste to print the punched diaphragm, printing on the first substrate layer, the second substrate layer, the third substrate layer and the fourth substrate layer, using the protective layer printing paste to print the protective layer, using the insulating layer printing paste to print the insulation under the outer electrode, the insulation under the pump electrode, the insulation on the pump electrode, the insulation on the reference electrode, the insulation under the reference electrode, the insulation on the heater, the insulation under the heater and the surface insulation, using the electrode layer printing paste to print the outer electrode, the terminal lead, the upper pump electrode, the lower pump electrode, the reference electrode and the heater layer, using the diffusion layer printing paste to print the pump electrode mixing cavity and the pump electrode diffusion barrier, and using the airway printing paste to print the airway; S6, stacking the dried zirconium oxide diaphragms in the order of a first substrate layer, a second substrate layer, a third substrate layer and a fourth substrate layer from bottom to top, vacuum packaging after stacking, and warm isostatic pressing after packaging, with the temperature set to 50° C. and the time set to 20 min; S7, chamfering and cutting the formed diaphragm, so that the preliminary model of the oxygen sensor chip has been produced; S8, sending the preliminarily formed chip into a sintering furnace for sintering, the temperature is set to 1450°C, the cobalt hydroxide nanostructure on the surface of the zirconium oxide film is converted into a tetracobalt trioxide nanofilm, and the chip is completely formed; S9, testing the fully formed chip, the testing including chip curvature test, sensor leakage test, strength test and electrical performance test, the electrical performance test also including heater resistance test, insulation resistance test and current test.

8. The method for manufacturing an intelligent wide-band five-wire oxygen sensor chip according to claim 7, characterized in that: The zirconium oxide casting slurry comprises 50-60% of 5 mol yttria-stabilized zirconium oxide casting powder, 2-5% of a dispersant, 10-15% of an organic solvent, 20-25% of a binder and 15-20% of an adhesive; The protective layer printing paste includes 25-30% alumina powder, 25-30% activated carbon powder, 2-5% adhesive, 30-35% organic solvent, 2-5% plasticizer and 1-3% dispersant; The insulating layer printing paste includes 45-55% of nano alumina powder, 2-5% of adhesive, 30-40% of organic solvent, 2-5% of plasticizer and 2-5% of dispersant; The electrode layer printing paste includes 65-75% of platinum powder, 3-8% of oxide, 2-5% of binder and 10-20% of organic solvent; The diffusion layer printing paste includes 40-50% zirconium oxide powder, 10-20% activated carbon powder, 2-5% adhesive, 25-35% organic solvent, 2-5% plasticizer and 1-3% dispersant; The airway printing slurry includes 20-30% activated carbon powder, 20-30% zirconium oxide powder, 2-5% binder, 40-50% organic solvent and 1-3% dispersant.

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