JP6437786B2 - Sensor substrate, sensor device, and sensor substrate manufacturing method - Google Patents

Description

  The present invention relates to a sensor substrate, a sensor device, and a sensor substrate manufacturing method including an insulating substrate and an electrode provided on the surface of the insulating substrate.

  As a sensor substrate used for an exhaust gas sensor or the like, a sensor substrate including an insulating substrate made of a ceramic sintered body such as an aluminum oxide sintered body and a detection electrode provided on the surface of the insulating substrate is used. (For example, refer to Patent Documents 1 and 2).

  For example, the resistance value or current value of the detection electrode changes as the detection object contained in the exhaust gas adheres to the detection electrode, and the inclusion of the detection object in the exhaust gas or the like due to the change in the resistance value or current value The amount is detected.

JP 55-30690 A JP 59-197847 A

  For example, in an exhaust gas sensor for an internal combustion engine, the sensor substrate is arranged so that the exhaust gas is in direct contact with the surface on which the detection electrode is provided. When the internal combustion engine is started, water droplets may be contained in the exhaust gas, and when the water droplets adhere to the insulating substrate surface of the sensor substrate, the portion where the water droplets adhere is rapidly cooled. Due to this rapid cooling, a large thermal shock is applied to the surface of the insulating substrate, and the insulating substrate is cracked. If the detection electrode is disconnected due to a crack in the insulating substrate, it becomes difficult to detect the object to be detected.

  An object of the present invention is to provide a highly reliable sensor substrate, sensor device, and method for manufacturing the sensor substrate.

A sensor substrate according to an aspect of the present invention is an insulating substrate having a main surface, the insulating substrate including a crystal phase containing alumina and manganese and a glass phase containing manganese, and the main surface of the insulating substrate. And at least a part of the glass phase is exposed on the main surface, the detection electrode is an Fe-Ni-Cr-Ti-Al alloy, and TiO is formed on the surface. It is characterized by having a passive film containing ₂ and Al ₂ O ₃ .

  A sensor device according to an aspect of the present invention includes the above-described sensor substrate and a power supply unit that supplies a potential to the detection electrode.

A sensor substrate manufacturing method according to an aspect of the present invention is a sensor substrate manufacturing method for manufacturing the sensor substrate, wherein a ceramic raw material containing alumina and manganese is formed into a green sheet. A step of applying a paste containing a metal material of Fe, Ni, Cr, Ti, and Al to the surface of the green sheet; and a step of simultaneously firing the green sheet and the paste applied to the surface of the green sheet And after the co-firing, heating at a temperature lower than the firing temperature of the co-firing.

According to the present invention, an insulating substrate having a major surface, an insulating substrate including a crystalline phase and glass phase containing manganese containing alumina and manganese, and the detection electrode provided on the main surface of the insulation substrate comprises a, at least a portion of the glass phase is exposed to the main surface of the insulation substrate, sensing electrode, a Fe-Ni-Cr-Ti- Al alloy, TiO ₂ on the surface and Al _It has a passive film containing ₂ O ₃ . Thereby, generation | occurrence | production of the crack of an insulated substrate is suppressed, generation | occurrence | production of the disconnection of a detection electrode is also suppressed, and a highly reliable sensor substrate is realizable.

  Further, according to the present invention, since the sensor substrate having the above-described configuration is provided, a highly reliable sensor device can be realized.

  Further, according to the present invention, after the green sheet and the conductor paste applied to the surface of the green sheet are simultaneously fired, the heat treatment is performed at a temperature lower than the firing temperature of the simultaneous firing. By the heat treatment after firing, the glass phase can immerse into the surface layer of the insulating substrate in an attempt to cover the surface of the crystalline phase, and the glass phase can be exposed on the surface of the insulating substrate.

(A) is a top view which shows the sensor board | substrate and sensor apparatus which are embodiment of this invention, (b) is sectional drawing in the cutting surface line AA of (a). It is an expanded sectional view which shows B part of FIG.1 (b). (A) is a top view which shows the sensor board | substrate and sensor apparatus which are other embodiment of this invention, (b) is sectional drawing which shows the sensor board | substrate and sensor apparatus which are further another embodiment of this invention. .

  A sensor substrate and a sensor device according to embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the upper and lower sides are distinguished from each other like the upper surface, but this is for convenience and does not limit the upper and lower sides when the sensor substrate or the like is actually used.

  Fig.1 (a) is a top view which shows the sensor board | substrate and sensor apparatus which are embodiment of this invention, FIG.1 (b) is sectional drawing in the cut surface line AA of Fig.1 (a). . The sensor substrate 4 is basically composed of the insulating substrate 1, the detection electrode 2 provided on the main surface (the upper surface in the example of FIG. 1) of the insulating substrate 1, and the internal wiring 3 which is a conductive path for connecting the detection electrode 2 to the outside. Is formed.

  The insulating substrate 1 is, for example, a flat plate shape such as a square plate shape, and is a base portion for providing the detection electrode 2 with electrical insulation. The insulating substrate 1 includes a crystal phase containing alumina and manganese and a glass phase containing manganese.

  In addition to alumina, the crystal phase may contain various ceramics such as mullite, zirconia, aluminum nitride, or glass ceramics.

The glass phase is an amorphous phase containing at least Mn ₂ O ₃ and further contains one or more oxides selected from Si, Mg, Ca, Sr, B, Nb, Cr and Co. The glass phase is preferably an amorphous phase containing Mn ₂ O ₃ , SiO ₂ and MgO.

  The glass phase exists in the insulating substrate 1 so as to be exposed at least on the main surface of the insulating substrate 1 on which the detection electrode 2 is provided. In the main surface of the insulating substrate 1, the ratio of the area occupied by the glass phase to the area occupied by the crystal phase when the insulating substrate 1 is viewed in plan is preferably 20% or more. The crystal phase exists as a plurality of crystal particles in the insulating substrate 1, and the glass phase exists as a grain boundary phase between the plurality of crystal particles. In particular, the glass phase is present in a large amount in the surface region of the insulating substrate 1 (for example, the depth from the main surface is about 3 μm), and a recess formed by being surrounded by crystal grains on the main surface of the insulating substrate 1 Exists to satisfy.

  Since the glass phase containing manganese has good wettability with respect to the alumina crystal phase, in the heat treatment after firing, the glass phase leaches into the surface layer of the insulating substrate 1 to cover the crystal particle surface, and most of the glass phase It is considered to exist on the surface layer.

  Thus, since the glass phase containing manganese is present so as to be exposed on the main surface on which the detection electrode 2 is provided, the insulating substrate 1 with few defects serving as a starting point of cracks and less prone to cracking can be obtained. Since the glass phase has a lower Young's modulus than the crystal phase containing alumina, for example, when it comes into contact with the exhaust gas, the thermal shock due to the attachment of water droplets to the insulating substrate 1 is mitigated, and the occurrence of cracks can be suppressed.

  By providing the insulating substrate 1 in which generation of cracks is suppressed, occurrence of disconnection of the detection electrode 2 and the internal wiring 3 is also suppressed, and a highly reliable sensor substrate 4 can be realized.

The presence of the manganese-containing glass phase exposed on the main surface on which the detection electrode 2 is provided means that the surface and cross-sectional photograph of the sensor substrate 4 and X-ray photoelectron spectroscopy using a scanning electron microscope (SEM), for example. This can be confirmed by analyzing the main surface of the sensor substrate 4 by analysis (XPS).

  The detection electrode 2 is provided on the main surface of the insulating substrate 1 and is a part for measuring the content of fine particles such as soot in the environment where the sensor substrate 4 is disposed. When fine particles such as soot adhere to the detection electrode 2, the electrical resistance between the pair of detection electrodes 2 changes. By detecting this change in electrical resistance, the mass of the fine particles in the environment where the detection electrode 2 is present is calculated and detected. Based on the mass of the fine particles and the flow rate (volume) of the gas in the environment where the detection electrode 2 exists, the content of the fine particles in the gas is calculated and detected.

  The environment in which the sensor substrate 4 is arranged is, for example, an exhaust passage for exhaust gas of an automobile. If the amount of fine particles detected by the sensor substrate 4 increases, it is detected that the content of fine particles flowing through the exhaust passage has increased. Thereby, for example, a failure of a DPF (Diesel Particulate Filter) that removes particulates such as soot from the exhaust gas can be detected.

  In order to effectively detect a change in resistance value due to adhesion of fine particles, the detection electrode 2 has a length such as a linear pattern including a comb-like pattern or an elongated rectangular (band-like) pattern, for example. It is preferable that the pattern is formed in a pattern that can be easily lengthened. In the embodiment shown in FIG. 1, an example is shown in which the detection electrode 2 is an elongated rectangular pattern.

  The internal wiring 3 is formed inside the insulating substrate 1 and electrically connects to the connection pads 5 provided on the lower surface of the insulating substrate 1. The internal wiring 3 is provided, for example, from the inside of the insulating substrate 1 to the other main surface (the lower surface in the example of FIG. 1) opposite to the main surface on which the detection electrode 2 is provided. Thereby, the detection electrode 2 is electrically led out to the outer surface such as the lower surface of the insulating substrate 1. The internal wiring 3 may include a through conductor (no symbol) that penetrates at least a part of the insulating substrate 1 in the thickness direction. Further, the internal wiring 3 may include a wiring conductor (without a symbol) such as a circuit pattern provided between the insulating layers. The internal wiring 3 can also be used as a heater wiring that generates heat.

In the sensor substrate 4 of the embodiment, connection pads 5 for external connection are provided on the lower surface of the insulating substrate 1. The connection pad 5 is directly connected to a portion of the internal wiring 3 that is electrically led to the lower surface of the insulating substrate 1. As a result, a conductive path (no symbol) is formed from the internal wiring 3 to the connection pad 5 on the lower surface of the insulating substrate 1. This conductive path is for electrically connecting the detection electrode 2 and an external electric circuit (not shown). When the connection pad 5 is bonded to a predetermined portion of the external electric circuit by a conductive bonding material such as solder or conductive adhesive, the detection electrode 2 and the external electric circuit are connected via the internal wiring 3 and the connection pad 5. Are electrically connected to each other.

The metal material used for the detection electrode 2, the internal wiring 3 and the connection pad 5 is preferably one having excellent oxidation resistance in a high temperature environment, for example, one in which a passive film containing oxide is formed on platinum or tungsten and the surface. Can be used. As a metal material on which a passive film containing an oxide is formed on the surface, for example, Fe—Ni—Cr—Ti—Al alloy, Fe—Cr—Al alloy, MoSi ₂ metal, or the like can be used.

  When platinum is used as the metal material, a conductive paste obtained by adding and mixing an appropriate organic binder and solvent to the platinum metal powder is preliminarily patterned in a ceramic green sheet to be the insulating substrate 1 by screen printing. It is formed on the surface or inside of the insulating substrate 1 by printing and coating on the ceramic green sheet and simultaneously firing with the ceramic green sheet to be the insulating substrate 1.

  In addition, by using a metal material on which a passive film containing an oxide is formed on the surface, even if a metal that is not easily oxidized such as platinum is used, it has a passive film on the surface. It becomes possible to make it excellent in oxidation resistance, and the sensor substrate 4 with high detection accuracy and long-term reliability can be provided.

  FIG. 2 is an enlarged cross-sectional view showing a portion B in FIG. As shown in FIG. 2, a passive film 2 a is formed on the surface of the detection electrode 2. Hereinafter, the passive film 2a formed on the surface of the detection electrode 2 will be described.

The passive film 2a contains TiO ₂ and Al ₂ O ₃ as oxides when the inside of the detection electrode 2 is a Fe—Ni—Cr—Ti—Al alloy. By adopting such a configuration, oversintering due to penetration of the glass phase contained in the insulating substrate 1 between the Fe—Ni—Cr—Ti—Al alloy particles is less likely to occur, suppressing the generation of voids, An increase in the electrical resistance of the wiring can be suppressed. Moreover, since the detection electrode 2 has the passive film 2a containing TiO ₂ and Al ₂ O ₃ on the surface, it can be made excellent in oxidation resistance in a high temperature environment.

Further, the passivation film 2a, when the inside of the detection electrode 2 is MoSi ₂ metal includes SiO ₂ as an oxide. By adopting such a configuration, oversintering due to penetration of the glass phase contained in the insulating substrate 1 into the MoSi ₂ metal particles is less likely to occur, suppressing the generation of voids, and increasing the electrical resistance of the wiring. Can be suppressed. Further, it is possible to detect the electrode 2 is because it has a passivation film 2a containing SiO ₂ and is excellent in oxidation resistance in a high-temperature environment on the surface.

  Moreover, the passive film 2a can be confirmed by performing an electron beam microanalyzer (EPMA) analysis for the surface part of the detection electrode 2, for example. The passive film formed on the surface of the connection pad 5 can be confirmed in the same manner as the detection electrode 2. The passive film formed on the surface of the internal wiring 3 can be confirmed by cutting the insulating substrate 1 so that the longitudinal cross section can be viewed, and performing EPMA analysis on the cut surface.

For the detection electrode 2, for example, a conductive paste obtained by adding and mixing an appropriate organic binder and solvent to each metal powder of Fe, Ni, Cr, Ti, and Al is screen-printed in advance on a ceramic green sheet to be the insulating substrate 1. Fe-Ni-Cr-Ti-Al alloy by printing and applying in a predetermined pattern by the method, etc., laminating ceramic green sheets on which conductor paste is formed, and simultaneously firing the ceramic green sheets to be the insulating substrate 1 Is formed on the insulating substrate 1 so as to have a passive film 2a on its surface. In this case, the mixing ratio of each metal powder is as follows: Fe powder 1-55 mass%, Ni powder 20-80 mass%, Cr powder 10-25 mass%, Ti powder 0.1-5 mass%, Al powder 0.1 It is preferable to set it as -5 mass%. Note that Fe-Ni-Cr-Ti-Al alloy powder having the above-described ratio may be used for the conductor paste. A metal powder of MoSi ₂ may be used instead of each metal powder of Fe, Ni, Cr, Ti, Al or Fe—Ni—Cr—Ti—Al alloy powder. In addition, the passive film 2a is formed in the state which contained the oxide in the surface of the detection electrode 2 at the time of the above-mentioned simultaneous baking.

  For example, the through conductor is subjected to a punching process such as mechanical punching or laser processing in a ceramic green sheet to be the insulating substrate 1 to provide a through hole, and a conductive paste made of a metal material as described above is provided in the through hole. It can be formed by filling and then co-firing.

  In addition, about the conductor paste used as the detection electrode 2 and the connection pad 5 which are provided exposed on the upper surface or the lower surface of the insulating substrate 1, it is printed in multiple times without printing to a predetermined thickness by one printing. You may do it.

  A metal plating layer may be further deposited on the surfaces of the detection electrode 2 and the connection pad 5 by electroplating or electroless plating. The metal plating layer is made of a metal having excellent corrosion resistance such as nickel, copper, gold or silver and connectivity with the connection member. For example, a nickel plating layer having a thickness of about 0.5 to 10 μm and 0.1 to A gold plating layer of about 3 μm, or a nickel plating layer of about 1 to 10 μm in thickness and a silver plating layer of about 0.1 to 1 μm are sequentially deposited. Accordingly, corrosion of the detection electrode 2, the connection pad 5, and the conductive path can be effectively suppressed, and the connection between the connection pad 5 and the external electric circuit or the connection between the connection pad 5 and the metal lead can be strengthened. .

  Moreover, you may interpose the metal plating layer which consists of metals other than the above, for example, a palladium plating layer.

  The sensor device 10 of the embodiment is formed by the sensor substrate 4 having the above configuration and the power supply unit 11 that supplies a potential to the detection electrode 2. About the sensor apparatus 10, the electric potential of about 50 volts (V) is supplied to the detection electrode 2 from the power supply part 11, and the leakage current by this electric potential is detected. The resistance value of the detection electrode 2 is detected by the value of this leakage current. The resistance value of the detection electrode 2 is measured by, for example, an external measurement detection circuit (not shown). In addition, a circuit for measuring a resistance value of the detection electrode 2 (not shown) may be disposed on the insulating substrate 1.

  The power supply unit 11 is, for example, a terminal electrically connected to an external power supply (not shown), a rectifier, a transformer circuit, and the like as a soot detection circuit, and is a part to which predetermined power is transmitted from the external power supply. The transmitted power is adjusted to a condition suitable for measuring the resistance value of the detection electrode 2 in the power supply unit 11 and transmitted to the detection electrode 2.

  The electrical connection between the power supply unit 11 and the detection electrode 2 is performed, for example, via the connection pad 5 and the internal wiring 3 described above. In FIG. 1, a connection conductor such as a conductive connection material that electrically connects the connection pad 5 and the power supply unit 11 is schematically shown by a virtual line (two-dot chain line).

  Since the sensor device 10 according to the embodiment includes the sensor substrate 4 having the above-described configuration, a highly reliable sensor device can be realized.

FIG. 3A is a plan view showing a sensor substrate and a sensor device according to another embodiment of the present invention, and FIG. 3B shows a sensor substrate and a sensor device according to still another embodiment of the present invention. It is sectional drawing shown. In FIG. 3, the same parts as those in FIG.

  In the embodiment shown in FIG. 3A, the shape of the detection electrode 2 is a comb-like shape unlike the band shape of the above-described embodiment. Further, the two comb-like detection electrodes 2 are arranged in such a positional relationship as to engage with each other. In this case, for example, the length of the detection electrode 2 can be increased while keeping the size of the insulating substrate 1 in plan view as small as possible. As the length of the detection electrode 2 is longer, the change in the resistance value as the detection electrode 2 tends to increase. In addition, it becomes easy to detect fine particles in the environment where the sensor substrate 4 is disposed. That is, even when the content of fine particles in the environment where the sensor substrate 4 is arranged is small, the fine particles can be detected more reliably.

  Therefore, in this case, it is possible to provide the sensor substrate 4 and the sensor device 10 that are more advantageous in terms of improvement in detection accuracy and sensitivity of fine particles in an environment in which the sensor substrate 4 is disposed and miniaturization in plan view. it can.

  In FIG. 3A, conductors such as connection pads for performing electrical connection between the power supply unit 11 and the detection electrode 2 are schematically shown by virtual lines (two-dot chain lines).

  In the embodiment shown in FIG. 3B, the lead terminal 6 is joined to the connection pad 5. In this case, the end of the lead terminal 6 opposite to the end joined to the connection pad 5 is joined to a predetermined part of the external electric circuit and electrically connected. That is, electrical and mechanical connection to the external electric circuit of the sensor substrate 4 (sensor device 10) is performed via the lead terminal 6. Different electrodes (positive electrode, negative electrode, etc.) of the power supply unit 11 are connected to different lead terminals 6, respectively. When mechanical connection between the sensor substrate 4 and the external electric circuit is performed via the lead terminal 6, the insulating substrate 1 of the sensor substrate 4 and the external electric circuit are provided by elastic deformation of the lead terminal 6. It becomes easier to relieve stress such as thermal stress due to a difference in thermal expansion from an external substrate (not shown) such as a resin substrate. Therefore, in this case, it is possible to provide the sensor substrate 4 and the sensor device 10 that are advantageous in improving the reliability of external connection and the like.

  Like the connection pad 5, the lead terminal 6 is not for detecting fine particles. Therefore, the material for forming the lead terminal 6 may be appropriately selected according to the environment in which the lead terminal 6 is used, the conditions such as the productivity and economy of the sensor substrate 4. For example, if the lead terminal 6 is made of a metal material having excellent oxidation resistance such as platinum or gold, it is advantageous in terms of reliability as the sensor device 10. In addition, the lead terminal 6 may be formed of an iron-based alloy such as an iron-nickel-cobalt alloy, copper, or the like with emphasis on economy and the like. Further, when the lead terminal 6 is made of an iron-based alloy, the exposed surface may be protected by a plating layer such as a gold plating layer.

  Joining of the lead terminal 6 to the connection pad 5 is performed by, for example, a brazing material (no symbol) such as silver brazing (silver copper brazing material) or gold brazing. Also for the brazing material, as with the lead terminal 6, the material is appropriately selected according to various conditions when the sensor substrate 4 is manufactured or used.

The sensor substrate and the sensor device of the present invention are not limited to the above embodiment, and various modifications are possible within the scope of the gist of the present invention. For example, a heater resistance circuit (not shown) or the like may be provided inside the insulating substrate 1. By preheating the detection electrode 2 with a heater, a sensor substrate and a sensor device that are easier to detect can be obtained. The resistance circuit as a heater is formed by the same method using the same material as that of the internal wiring 3, for example.

Next, a method for manufacturing the insulating substrate 1 of the present embodiment will be described. (1) A powder of silicon oxide (SiO ₂ ), magnesium oxide (MgO), manganese oxide (Mn ₂ O ₃ ) or the like is added as a sintering aid to the alumina (Al ₂ O ₃ ) powder, and an appropriate binder Add solvent and plasticizer, then knead the mixture into a slurry. Thereafter, a ceramic green sheet is obtained by a conventionally known forming method such as a doctor blade method.

  (2) The formed ceramic green sheet is punched using a punching die at a site that becomes a through conductor, or a through hole is formed using a laser.

  (3) Conductive paste for forming the detection electrode 2 on the upper surface of the insulating substrate 1, the internal wiring 3 including the through conductor and the wiring conductor inside the insulating substrate 1, and the connection pad 5 on the lower surface or side surface of the insulating substrate 1, respectively. Print on the surface of the ceramic green sheet and fill the through hole with the conductive paste.

  (4) A ceramic green sheet laminate in which a conductor paste is printed and applied and the through holes are filled with the conductor paste is laminated.

  (5) This ceramic green sheet laminate is cut and separated into laminates to be individual insulating substrates 1, and the ceramic green sheet and the conductive paste are simultaneously fired at a firing temperature of about 1400-1600 ° C. to obtain a sintered body. obtain.

  (6) The obtained sintered body is heated at a temperature lower than the firing temperature (about 700 to 1000 ° C.). By this heat treatment, the insulating substrate 1 in which the glass phase containing manganese oozes out to the surface layer and the glass phase containing manganese is exposed on the main surface is obtained.

  (7) A metal plating layer for protecting the detection electrode 2 and the connection pad 5 to prevent oxidation and to facilitate brazing is applied to the surfaces of the detection electrode 2 and the connection pad 5.

  This insulating substrate 1 can be produced in batches by making multiple pieces, and a dividing groove is formed along the outer edge of the insulating substrate 1 formed by firing and obtained by baking. A method of breaking along the groove and dividing, or a method of cutting along a portion serving as the outer edge of the insulating substrate 1 by a slicing method or the like can be used. In addition, although a division | segmentation groove | channel can be formed by cutting smaller than the thickness of the insulating substrate 1 formed by multi-slicing with a slicing apparatus after baking, the ceramic green sheet laminated body for insulating substrates 1 formed by multi-slicing Alternatively, it may be formed by pressing a cutter blade against the molded body or by cutting with a slicing device smaller than the thickness of the laminated body or molded body.

  In addition, by firing individual laminates or molded bodies cut out from ceramic green sheet laminates or molded bodies, or ceramic green sheet laminates or molded bodies having a large number of insulating substrates 1, each sensing electrode 2, The connection pad 5 is baked and deposited. That is, each detection electrode 2 and the connection pad 5 are formed with a thickness of 5 to 30 μm.

  Further, in order to protect and prevent oxidation of the detection electrode 2 and the connection pad 5 on the surface of the insulating substrate 1, the detection electrode 2 and the connection pad 5 on the surface exposed on the surface of the insulating substrate 1 are protected from heat. In order to improve the thickness, it is preferable to sequentially deposit a gold (Au) plating layer having a thickness of 0.1 to 3 μm.

  The present invention is not limited to the example of the above-described embodiment. For example, a plurality of detection electrodes 2, internal wirings 3, and connection pads 5 may be provided on the insulating substrate 1.

DESCRIPTION OF SYMBOLS 1 Insulating board 2 Detection electrode 2a Passive film 3 Internal wiring 4 Sensor board 5 Connection pad 6 Lead terminal 10 Sensor apparatus 11 Power supply part

Claims (5)

An insulating substrate having a main surface, the insulating substrate including a crystal phase containing alumina and manganese and a glass phase containing manganese;
A detection electrode provided on the main surface of the insulating substrate,
At least a part of the glass phase is exposed on the main surface ,
The sensor substrate is an Fe—Ni—Cr—Ti—Al alloy, and has a passive film containing TiO ₂ and Al ₂ O ₃ on a surface thereof .   The sensor substrate according to claim 1, wherein the glass phase contains one or more oxides selected from Si, Mg, Ca, Sr, B, Nb, Cr, and Co. The glass phase, the sensor substrate according to claim 1 or claim 2, characterized in that present between the plurality of crystal particles made of the crystalline phase. The sensor substrate according to any one of claims 1 to 3 ,
And a power supply unit for supplying a potential to the detection electrode. It is a manufacturing method of the sensor substrate which manufactures the sensor substrate according to any one of claims 1 to 3 ,
Forming a ceramic raw material containing alumina and manganese into a green sheet;
Applying a paste containing a metal material of Fe, Ni, Cr, Ti, Al to the surface of the molded green sheet;
Co-firing the green sheet and the paste applied to the surface of the green sheet;
And a step of heating at a temperature lower than the firing temperature of the co-firing after the co-firing.

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