WO2010113711A1 - Capacitive humidity sensor and manufacturing method therefor - Google Patents

Capacitive humidity sensor and manufacturing method therefor Download PDF

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Publication number
WO2010113711A1
WO2010113711A1 PCT/JP2010/055026 JP2010055026W WO2010113711A1 WO 2010113711 A1 WO2010113711 A1 WO 2010113711A1 JP 2010055026 W JP2010055026 W JP 2010055026W WO 2010113711 A1 WO2010113711 A1 WO 2010113711A1
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Prior art keywords
film
upper electrode
electrode film
lower electrode
humidity sensor
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PCT/JP2010/055026
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French (fr)
Japanese (ja)
Inventor
聡 和賀
澄人 森田
一聡 五十嵐
崇 佐藤
昌彦 石曽根
清 佐藤
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アルプス電気株式会社
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Priority to JP2011507113A priority Critical patent/JPWO2010113711A1/en
Publication of WO2010113711A1 publication Critical patent/WO2010113711A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
    • G01N27/223—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance for determining moisture content, e.g. humidity
    • G01N27/225—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance for determining moisture content, e.g. humidity by using hygroscopic materials

Definitions

  • the present invention relates to a capacitive humidity sensor using a polymer moisture sensitive film as a dielectric and a method of manufacturing the same.
  • Humidity sensors used for humidity change measurement include capacitive humidity sensors in which a polymer moisture sensitive film whose dielectric constant changes in accordance with humidity (the amount of adsorbed water) is used as a dielectric.
  • this type generally includes a sensor unit that changes its capacitance according to humidity and a reference unit that holds a constant capacitance regardless of humidity, and converts the capacitance difference between the sensor unit and the reference unit into a voltage. Output.
  • the sensor unit has a laminated structure in which a silicon nitride film and a moisture sensitive film made of a polymer material are formed on a comb electrode, and the reference unit is a laminated structure in which a silicon nitride film is formed on the comb electrode Have.
  • a capacitive humidity sensor is described, for example, in Patent Document 1.
  • the film configuration (dielectric constant of the entire film) on the comb electrode differs depending on the presence or absence of the polymer moisture sensitive film in the sensor portion and the reference portion. ) Is not identical but is complicated. For this reason, the electrostatic capacitance of the sensor unit varies from individual to individual due to variations in the film thickness of the polymer moisture sensitive film and the heat treatment process, and the capacitance difference (sensor output) between the sensor unit and the reference unit varies. In addition, since the temperature dependency of the capacitance differs depending on the presence or absence of the polymer moisture sensitive film in the sensor unit and the reference unit, the temperature dependency of the capacitance difference is generated.
  • An object of the present invention is to obtain a capacitive humidity sensor capable of reducing variations in temperature of a sensor unit and a reference unit, and a method of manufacturing the same, based on the above problem awareness.
  • the present invention adopts a parallel plate structure in which a polymer moisture sensitive film is sandwiched between upper and lower electrodes in the sensor part and the reference part, and the sensor part and the reference part are formed in the same process using the same electrode material and dielectric material.
  • the variation in the capacitance difference caused by the difference in the manufacturing process is suppressed, and the capacitance of the sensor unit and the capacitance of the reference portion have the same temperature characteristics, so the temperature dependency of the capacitance difference can be reduced.
  • a sensor unit whose capacitance changes according to humidity and a reference unit whose capacitance does not change regardless of humidity are provided on the same substrate, and the capacitance difference between the sensor unit and the reference unit is a voltage.
  • the sensor unit and the reference unit have the same parallel plate structure in which the polymer moisture sensitive film whose dielectric constant changes according to the humidity is sandwiched between the lower electrode film and the upper electrode film.
  • the upper electrode film is provided with at least one opening for exposing the polymer moisture sensitive film, and in the reference section, the moisture impermeable protective film is formed on the upper electrode film. It is characterized in that the polymer moisture sensitive film is covered with at least one of the upper electrode film and the moisture impermeable protective film.
  • the upper electrode film of the reference portion may be provided with the same opening as the one or more openings provided in the upper electrode film of the sensor unit.
  • the polymeric moisture sensitive film located under each opening is covered with a moisture impermeable protective film formed on the upper electrode film.
  • the upper electrode film of the sensor unit is covered with a moisture impermeable protective film to prevent corrosion.
  • the lower electrode film, the polymer moisture sensitive film, and the upper electrode film have a mirror-inverted pattern in the sensor portion and the reference portion. According to this aspect, the symmetry between the sensor unit and the reference unit is improved, and the electrostatic capacitance values in the sensor unit and the reference unit can be easily equalized.
  • the lower electrode film can be provided commonly to the sensor unit and the reference unit.
  • the polymer moisture sensitive film and the upper electrode film are separately provided in the sensor unit and the reference unit.
  • the lower electrode wiring includes one end connected to the electrode pad and the other end connected to the lower electrode film at a midpoint between the sensor unit and the reference unit.
  • the upper electrode film of the sensor unit has a capacitance correction area located at the central portion thereof and having no opening.
  • the capacitance correction area By changing the size of the capacitance correction area, the facing area of the upper electrode film and the lower electrode film can be easily changed, and the correction of the capacitance value (initial capacitance value) of the sensor unit under predetermined conditions becomes easy.
  • the step of simultaneously forming a pair of identical lower electrode films on a substrate and the same step of changing the dielectric constant according to humidity on the pair of lower electrode films In the step of simultaneously forming a polymer moisture-sensitive film, and on the pair of polymer moisture-sensitive films, the same upper electrode film which covers the polymer moisture-sensitive film entirely and faces in parallel to the lower electrode film A step of simultaneously forming, a step of simultaneously forming at least one opening for exposing the polymer moisture-sensitive film in the pair of upper electrode films, an upper electrode film of one and an opening of the upper electrode film of one Forming a non-moisture-permeable protective film covering the lower polymer moisture-sensitive film and exposing the other upper electrode film and the polymer moisture-sensitive film located under the opening of the other upper electrode film; It is characterized by having. In practice, in order to prevent electrode corrosion, it is preferable to further cover the other upper electrode film with a moisture impermeable protective film.
  • the step of simultaneously forming a pair of identical lower electrode films on the substrate, and on the pair of lower electrode films, the same polymer moisture-sensitive film whose dielectric constant changes according to humidity A step of forming simultaneously, a step of simultaneously forming an upper electrode film covering the polymer moisture sensitive film and facing in parallel to the lower electrode film on the pair of polymer moisture sensitive films; Forming a non-moisture permeable protective film covering the upper electrode film, and shaving one non-moisture permeable protective film and the upper electrode film to form one or more openings for exposing the polymer moisture sensitive film It is characterized by having.
  • the step of simultaneously forming a pair of identical lower electrode films on a substrate, and the same polymer moisture sensitive material whose dielectric constant changes according to humidity on the pair of lower electrode films Simultaneously forming a film, and simultaneously forming, on the pair of polymer moisture-sensitive films, the same upper electrode film which covers the polymer moisture-sensitive films and faces in parallel to the lower electrode film. And forming a non-moisture-permeable protective film covering the pair of upper electrode films.
  • the pair of lower electrode films, the pair of polymer moisture sensitive films, and the pair of upper electrode films are formed in a pattern shape in which the mirrors are inverted to each other.
  • the pair of lower electrode films can be formed of an integral common electrode film connected to each other. In this case, if the lower electrode wiring whose one end is connected to the electrode pad and the other end is connected to the middle position of the lower electrode film is provided, the symmetry between the reference part and the sensor part is improved.
  • a capacity correction area having no opening is provided at the center of one upper electrode film, and the size of the capacity correction area allows the one upper electrode film, the polymer moisture sensitive film, and the lower electrode film at a specific humidity to be obtained. It is preferable to correct the capacitance value by. According to this aspect, it is possible to easily adjust the initial capacitance value of the sensor unit in which the capacitance changes in accordance with the humidity, and to reduce the variation in capacitance difference between the sensor unit and the reference unit.
  • the sensor portion and the reference portion have the same parallel plate structure in which the polymer moisture sensitive film is interposed between the lower electrode film and the upper electrode film, and the same electrode material and dielectric material are used. Since it is formed by the manufacturing process (mirror inversion pattern formation), the capacity variation due to the difference in structure and process is eliminated, and the sensor capacity and the reference capacity have the same temperature characteristics.
  • the initial capacitance value of the sensor unit can be easily adjusted by the capacitance correction area provided in the upper electrode film of the sensor unit. As a result, it is possible to obtain a capacitive humidity sensor capable of reducing the variation in temperature difference between the sensor unit and the reference unit and the temperature dependency, and a method of manufacturing the same.
  • FIG. 6 is a cross-sectional view (a cross-sectional view taken along the line II-II in FIG. 3) showing the structure of the sensor portion and the reference portion of the capacitive humidity sensor according to the first embodiment of the present invention. It is a top view which shows the structure of the sensor part of the same capacitive humidity sensor, and a reference
  • FIG. 5 is a cross-sectional view showing the next step of FIG. 4;
  • FIG. 6 is a cross-sectional view showing the next process of FIG. 5; FIG.
  • FIG. 7 is a cross-sectional view showing the next process of FIG. 6;
  • FIG. 10 is a cross-sectional view (cross-sectional view along the line VIII-VIII in FIG. 9) of the capacitive humidity sensor according to the second embodiment of the present invention in which the upper electrode film of the reference portion is not provided with an opening. It is a top view of the same capacitive humidity sensor.
  • FIG. 7 is a plan view of a capacitive humidity sensor according to a third embodiment of the present invention.
  • FIG. 11 is a cross-sectional view of the same capacitive humidity sensor (cross-sectional view along the line XI-XI in FIG. 10). It is a schematic diagram explaining the wiring connection of the same capacitive humidity sensor.
  • FIG. 15 is a cross-sectional view of the same capacitive humidity sensor (cross-sectional view along the line XV-XV in FIG. 14).
  • FIG. 1 is a block diagram showing the main configuration of the capacitive humidity sensor 100 according to the present invention
  • FIG. 2 is a cross sectional view of the capacitive humidity sensor 100 (cross sectional view along line II-II in FIG. 3)
  • FIG. It is a top view which shows the parallel plate structure common to the sensor part 20 and the reference part 30 of the sensor 100.
  • FIG. 1 is a block diagram showing the main configuration of the capacitive humidity sensor 100 according to the present invention
  • FIG. 2 is a cross sectional view of the capacitive humidity sensor 100 (cross sectional view along line II-II in FIG. 3)
  • FIG. It is a top view which shows the parallel plate structure common to the sensor part 20 and the reference part 30 of the sensor 100.
  • FIG. 1 is a block diagram showing the main configuration of the capacitive humidity sensor 100 according to the present invention
  • FIG. 2 is a cross sectional view of the capacitive humidity sensor 100 (cross sectional view along line II-II in FIG. 3)
  • the capacitive humidity sensor 100 is a polymer film humidity sensor in which a polymer moisture sensitive material whose dielectric constant changes according to the amount of absorbed or released water is used as a dielectric.
  • the capacitive humidity sensor 100 has a sensor unit 20 whose capacitance C20 changes with humidity and a constant capacitance C30 regardless of humidity on a substrate 10 made of, for example, silicon whose surface is protected by an insulator.
  • a reference unit 30 to be held and a circuit unit electrically connected to the sensor unit 20 and the reference unit 30, and converting a capacitance difference ⁇ C ( C20-C30) between the sensor unit 20 and the reference unit 30 into a voltage and outputting it And 40.
  • the circuit unit 40 is provided with a connection pad 40 a for connection to an external circuit.
  • reference numeral 10a is a Si layer
  • 10b is an insulating layer.
  • the sensor unit 20 and the reference unit 30 are formed of the lower electrode film 11, the polymer moisture sensitive film 12, and the upper electrode film 13 formed by the same process using the same electrode material and dielectric material (polymer moisture sensitive material). Have the same parallel plate structure (FIG. 2, FIG. 3).
  • the lower electrode film 11 has a rectangular planar shape, and is formed on the substrate 10 with a uniform film thickness.
  • the polymer moisture sensitive film 12 is made of polyimide and is laminated on the lower electrode film 11 with a uniform film thickness. In FIG. 3, the polymer moisture sensitive film 12 is shown hatched.
  • the upper electrode film 13 has a rectangular planar shape in the same manner as the lower electrode film 11 and is formed on the polymer moisture sensitive film 12 with a uniform film thickness.
  • the lower electrode film 11 and the upper electrode film 13 are made of an electrode material such as, for example, Al, Ta, Ti, NiFe, Ni or the like.
  • the polymer moisture sensitive film 12 covers one end of the lower electrode film 11 from the substrate 10 and is positioned on the lower electrode film 11, and the upper electrode film 13 is formed of the polymer moisture sensitive film 12 from the substrate 10.
  • the planar position of the polymer moisture sensitive film 12 and the upper electrode film 13 is shifted with respect to the lower electrode film 11 so as to cover the one end portion and be located on the polymer moisture sensitive film 12. Even when the polymer moisture sensitive film 12 and the upper electrode film 13 are provided only on the lower electrode film 11 by aligning the planar positions of the polymer moisture sensitive film 12 and the upper electrode film 13, the polymer moisture sensitive film 12 is May be provided to cover the lower electrode film 11.
  • the upper electrode film 13 is provided with a large number of openings ⁇ for exposing the polymer moisture sensitive film 12.
  • the large number of openings ⁇ are arranged at predetermined intervals in the left and right and up and down directions in a region facing the lower electrode film 11, and have a planar rectangular shape.
  • the number, planar shape and formation position of the openings ⁇ are arbitrary.
  • the moisture impermeable protective film 14 for blocking the exchange of water with the atmosphere is formed on the upper electrode film 13, and the aperture ⁇ of the upper electrode film 13 is covered with the nonpermeable protective film 14 ing.
  • the moisture impermeable protective film 14 is made of, for example, a silicon nitride film (SiNx film), an SiO 2 film, an Al 2 O 3 / SiO 2 laminated film, or an SiO 2 / SiN laminated film.
  • the polymer moisture sensitive film 12 is covered with the upper electrode film 13 and the moisture impermeable protective film 14 and is not exposed to the atmosphere, so even if the humidity (the amount of water) in the atmosphere changes, the polymer moisture sensitive film 12 is The amount of water does not change, nor does the dielectric constant .epsilon. Change. Thereby, a constant capacitance C30 is held between the lower electrode film 11 and the upper electrode film 13.
  • a reference capacitance C30 the capacitance accumulated between the lower electrode film 11 and the upper electrode film 13 of the reference portion 30.
  • the moisture impermeable protective film 14 covers only the upper electrode film 13, and many openings ⁇ provided in the upper electrode film 13 are not covered with the moisture impermeable protective film 14. Since the polymer moisture sensitive film 12 is exposed to the atmosphere through the large number of openings ⁇ , the amount of water absorbed or released changes according to the humidity (the amount of water) in the atmosphere, and the dielectric constant ⁇ changes Do. As a result, the capacitance C20 between the lower electrode film 11 and the upper electrode film 13 changes. In the following description, the capacitance accumulated between the lower electrode film 11 and the upper electrode film 13 of the sensor unit 20 is referred to as a sensor capacitance C20.
  • An external circuit connected to the capacitive humidity sensor 100 via the pad 40a can detect a humidity change (relative humidity) from the output of the capacitive humidity sensor 100 (voltage corresponding to the capacitance difference ⁇ C).
  • FIGS. 4 to 7 are sectional views showing manufacturing steps of the capacitive humidity sensor 100. As shown in FIG.
  • the same lower electrode film 11 means the lower electrode film 11 having the same planar shape, film configuration, and film thickness, which is formed by the same process using the same electrode material.
  • an electrode material of the lower electrode film 11 for example, Al, Ta, Ti, NiFe, Ni are used.
  • the lower electrode film 11 is formed in a flat rectangular shape, but the planar shape of the lower electrode film 11 is arbitrary. In the step of forming the lower electrode film 11, the wiring conductor of the circuit section 40 and the pad 40a can be formed simultaneously.
  • the same polymer moisture sensitive film 12 whose dielectric constant changes according to the humidity is formed on the pair of lower electrode films 11, respectively.
  • the same polymer moisture sensitive film 12 refers to a polymer moisture sensitive film having the same planar shape, film configuration, and film thickness formed by the same process using the same polymer moisture sensitive material.
  • the film 12 is meant.
  • the polymer moisture sensitive film 12 can be formed by applying polyimide as a polymer moisture sensitive material on the lower electrode film 11 and curing the polyimide by heat treatment. At this time, the film thickness of the polymer moisture sensitive film 12 is controlled to match the desired facing distance d between the lower electrode film 11 and the upper electrode film 13.
  • the polymer moisture sensitive film 12 is formed not only on the lower electrode film 11 but also from one end of the lower electrode film 11 to the substrate 10, but the polymer moisture sensitive film 12 is the lower electrode film 11 may be formed so as to cover it.
  • the polymer moisture sensitive film is opposed on the pair of polymer moisture sensitive films 12 in parallel with the lower electrode film 11 by using the photolithography technology.
  • the same upper electrode film 13 having a large number of openings ⁇ for exposing 12 is formed.
  • “the same upper electrode film 13” means the upper electrode film 13 having the same planar shape, film configuration and film thickness, which is formed by the same process using the same electrode material.
  • the electrode material of the upper electrode film 13 for example, Al, Ta, Ti, NiFe, and Ni are used similarly to the lower electrode film 11.
  • the upper electrode film 13 of the present embodiment has a flat rectangular shape and is formed not only on the polymer moisture sensitive film 12 but also from one end of the polymer moisture sensitive film 12 to the substrate 10. It may be formed only on the moisture sensitive film 12 (area opposed to the lower electrode film 11), and its planar shape is also arbitrary. Further, in the present embodiment, the planar shape of each opening ⁇ is rectangular, and in the region where the upper electrode film 13 faces the lower electrode film 11, many openings ⁇ are arranged vertically and horizontally. The number, planar shape and formation position can be set appropriately.
  • the moisture impermeable protective film 14 is made of a material that blocks moisture exchange with the atmosphere, such as a silicon nitride film (SiNx film), an SiO 2 film, an Al 2 O 3 / SiO 2 laminated film, or an SiO 2 / SiN laminated film. Is preferred. It is practical to form this moisture impermeable protective film 14 on the entire surface of the substrate except for the large number of openings ⁇ provided on the other upper electrode film 13 described above and the pads 40 a of the circuit section 40.
  • the sensor portion 20 is obtained from the parallel plate structure of the upper electrode film 13, the polymer moisture sensitive film 12 and the lower electrode film 11 on the side where the opening ⁇ is not covered with the moisture impermeable protective film 14.
  • a reference portion 30 is obtained from a parallel plate structure of the upper electrode film 13, the polymer moisture sensitive film 12 and the lower electrode film 11 on the side where the opening ⁇ is covered with the moisture impermeable protective film 14, as shown in FIGS.
  • the capacitive humidity sensor 100 is completed.
  • the capacitive humidity sensor 100 As described above, in the capacitive humidity sensor 100, a common parallel plate structure (lower electrode) formed by the same manufacturing process (FIGS. 4 to 7) using the same electrode material and dielectric material (polymer moisture sensitive material) Since the sensor unit 20 and the reference unit 30 are formed of the film 11, the polymer moisture sensitive film 12 and the upper electrode film 13), the sensor capacitance C20 and the film thickness of the polymer moisture sensitive film 12 and the variations in the heat treatment The variation of the reference capacitance C30 is reduced, and the temperature dependency of the capacitance difference ⁇ C between the sensor unit 20 and the reference portion 30 is also reduced because the sensor capacitance C20 and the reference capacitance C30 have the same temperature characteristic. Thereby, the variation in the capacitance difference ⁇ C between the sensor unit 20 and the reference unit 30 is reduced, and the detection accuracy of the capacitive humidity sensor 100 is improved.
  • FIGS. 8 and 9 are a cross-sectional view and a plan view showing a capacitive humidity sensor 200 according to a second embodiment in which no opening is provided in the upper electrode film 13 on the reference portion 30 side.
  • the polymer moisture sensitive film 12 is shown by hatching.
  • the capacitive humidity sensor 200 does not have the moisture impermeable protective film 14 covering the pair of upper electrode films 13 except for the pad 40 a of the circuit section 40.
  • the capacitive humidity sensor 200 does not have the moisture impermeable protective film 14 covering the pair of upper electrode films 13 except for the pad 40 a of the circuit section 40.
  • FIGS. 10 to 12 show a capacitive humidity sensor 300 according to a third embodiment provided with the lower electrode film 311 common to the sensor unit 20 and the reference unit 30.
  • FIG. 10 is a plan view of the capacitive humidity sensor 300
  • FIG. 11 is a sectional view of the capacitive humidity sensor
  • FIG. 12 is a schematic view showing the wiring connection between the lower electrode film 11 and the electrode pad.
  • the moisture impermeable protective film 14 is omitted, and the polymer moisture sensitive film 12 is hatched.
  • the capacitive humidity sensor 300 has a lower electrode film 311, a polymer moisture sensitive film 12, and a lower electrode film 311 formed in a mirror-inverted pattern with respect to a virtual center line X indicated by a broken line in FIG.
  • An upper electrode film 13 is provided.
  • the virtual center line X is set at an intermediate position between the sensor unit 20 and the reference unit 30.
  • the lower electrode film 311 is an electrode film having a rectangular shape in plan view provided from the sensor unit 20 to the reference unit 30, and is commonly provided to the sensor unit 20 and the reference unit 30.
  • the lower electrode wiring 321 is drawn to the lower electrode film 311 from an intermediate position between the sensor unit 20 and the reference unit 30, and is connected to the electrode pad 40 a of the circuit unit 40 via the lower electrode wiring 321.
  • the lower electrode wiring 321 has one end connected to the electrode pad 40a of the circuit unit 40, and the other end intermediate between the sensor unit 20 and the reference unit 30 (virtual center
  • the lower electrode film 311 is connected at the position of the line X).
  • the lower electrode wiring 321 is drawn out from an intermediate position between the sensor unit 20 and the reference unit 30, the symmetry of the sensor unit 20 and the reference unit 30 is improved electrically, and variations in the sensor capacitance C20 and the reference capacitance C30 are obtained. It can be reduced.
  • the lower electrode wiring 321 can be formed simultaneously with the same material as the lower electrode film 311.
  • the polymer moisture sensitive film 12 and the upper electrode film 13 are separately provided in the sensor unit 20 and the reference unit 30.
  • an upper electrode wire 323 connecting the upper electrode film 13 and the electrode pad 40a of the circuit section 40 is provided on the upper electrode film 13, as shown in FIG. 12, an upper electrode wire 323 connecting the upper electrode film 13 and the electrode pad 40a of the circuit section 40 is provided on the upper electrode film 13, as shown in FIG. 12, an upper electrode wire 323 connecting the upper electrode film 13 and the electrode pad 40a of the circuit section 40 is provided.
  • the upper electrode wiring 323 is a wiring pattern extended from the pair of upper electrode films 13 by a fixed width, so that the parasitic capacitances generated by the sensor unit 20 and the reference unit 30 become the same. It has been adjusted. Thereby, the variation of the sensor capacitance C20 and the reference capacitance C30 due to the parasitic capacitance is reduced.
  • the upper electrode wiring 323 can be formed simultaneously with the same material as the upper electrode film 13.
  • the capacitive humidity sensor 300 can be manufactured as follows.
  • the lower electrode film 311 common to the sensor portion and the reference portion is formed on the substrate 10 made of, for example, silicon.
  • the lower electrode film 311 is formed in a pattern shape which is mirror-inverted with respect to a virtual center line X assumed at an intermediate position between the sensor portion to be formed and the reference portion.
  • the lower electrode film 311 of the present embodiment is formed in a rectangular shape in plan view in which the mirror inversion is performed with respect to the virtual center line X, but the planar shape of the lower electrode film 311 is arbitrary as long as the mirror inversion is performed with respect to the virtual center line X is there.
  • Al, Ta, Ti, NiFe, and Ni are used as an electrode material of the lower electrode film 311.
  • at least one of the wiring conductor (lower electrode wiring 321) of the circuit section 40 and the pad 40a can be simultaneously formed.
  • a pair of the polymer moisture sensitive films 12 whose dielectric constant changes according to the humidity is formed in a rectangular shape in plan view with mirror inversion with respect to the virtual center line X.
  • the planar shapes of the pair of polymer moisture sensitive films 12 are arbitrary as long as they mirror-invert with respect to the virtual center line X.
  • the high molecular weight moisture sensitive film 12 can be formed by applying polyimide as a high molecular weight moisture sensitive material on the lower electrode film 11 and curing the polyimide by heat treatment. At this time, the film thickness of the polymer moisture sensitive film 12 is controlled to match the desired facing distance d between the lower electrode film 11 and the upper electrode film 13.
  • the polymer moisture sensitive film 12 is formed not only on the lower electrode film 11 but also from one end of the lower electrode film 11 to the substrate 10, but the polymer moisture sensitive film 12 is the lower electrode film It may be formed only on 11.
  • the electrode films 13 are formed in a pair in a rectangular shape in plan view smaller than the polymer moisture-sensitive film 12 mirror-inverted with respect to the virtual center line X.
  • the planar shape of the pair of upper electrode films 13 is arbitrary as long as mirror inversion is performed with respect to the virtual center line X.
  • the planar shape of each opening ⁇ is rectangular, and a large number of openings ⁇ are arranged in the upper, lower, left, and right directions in the region where the upper electrode film 13 faces the lower electrode film 11.
  • the planar shape and the formation position can be set as appropriate.
  • the electrode material of the upper electrode film 13 for example, Al, Ta, Ti, NiFe, and Ni are used similarly to the lower electrode film 11.
  • the step of forming the upper electrode film 13 at least one of the wiring conductor (upper electrode wiring 323) of the circuit section 40 and the pad 40a can be simultaneously formed.
  • the moisture impermeable protective film 14 is made of a material that blocks moisture exchange with the atmosphere, such as a silicon nitride film (SiNx film), an SiO 2 film, an Al 2 O 3 / SiO 2 laminated film, or an SiO 2 / SiN laminated film. Is preferred. It is practical to form this moisture impermeable protective film 14 on the entire surface of the substrate except for the large number of openings ⁇ provided on the other upper electrode film 13 described above and the pads 40 a of the circuit section 40.
  • the sensor portion 20 is obtained from the parallel plate structure of the upper electrode film 13, the polymer moisture sensitive film 12 and the lower electrode film 311 on the side where the opening ⁇ is not covered with the moisture impermeable protective film 14.
  • the reference portion 30 is obtained from a parallel plate structure of the upper electrode film 13, the polymer moisture sensitive film 12, and the lower electrode film 311 on the side where the opening ⁇ is covered with the moisture impermeable protective film 14 as shown in FIGS.
  • the capacitive humidity sensor 100 is completed.
  • the moisture impermeable protective film 14 covering the upper electrode film 13 of the sensor unit 20 can be omitted, the moisture impermeable protective film 14 is preferably provided for preventing the corrosion of the upper electrode film 13.
  • FIG. 13 is a schematic view showing a comparative example of the wiring connection of the capacitive humidity sensor.
  • the lower electrode wiring 321 may be drawn out from one of the sensor unit 20 and the reference unit 30 (the sensor unit 20 in FIG. 13).
  • FIGS. 14 and 15 are a plan view and a cross-sectional view of a capacitive humidity sensor 400 of the fourth embodiment capable of correcting the initial capacitance value of the sensor unit 20.
  • FIG. 14 the moisture-impermeable protective film 14 is omitted, and the polymer moisture-sensitive film 12 is hatched.
  • the initial stage is to ensure its reliability. It is necessary to correct the electrostatic capacitance value (initial capacitance value) of the sensor unit so that the sensor capacitance in the initial state and the reference capacitance coincide with each other.
  • the capacitive humidity sensor 400 is substantially the same as the capacitive humidity sensor 300 of the third embodiment, but a capacitance correction area 450 having no opening at the center of the upper electrode film 13 of the sensor unit 20 is provided. This differs from the capacitive humidity sensor 300 of the third embodiment.
  • the capacitive humidity sensor 300 of the third embodiment By providing the solid film-like capacity correction area 450, the area facing the lower electrode film 311 of the upper electrode film 13 of the sensor unit 20 increases or decreases according to the size (area) of the capacity correction area 450. Thus, the sensor capacitance C20 can be corrected.
  • the initial capacitance correction of the sensor unit 20 has been performed by changing the area of the upper electrode film 13, but in the outer peripheral portion of the upper electrode film 13 and the lower electrode film 311, the capacitance per unit area due to the edge effect The value was not stable, and it was difficult to obtain the target initial capacity value. If the capacitance correction area 450 is provided at the central portion of the upper electrode film 13 as in the present embodiment, the capacitance value per unit area is stable at the central portion. Is much easier.
  • the capacitive humidity sensor 400 is manufactured as follows.
  • the pair of upper electrode films 13 are formed in a solid film shape. Then, before forming a large number of openings ⁇ in the pair of upper electrode films 13, the sensor capacitance C20 and the reference capacitance C30 in the initial state are measured, and from the measurement results, the sensor capacitance C20 and the reference capacitance C30 match in the initial state A correction value (initial capacitance value of the sensor unit 20) required to do this is obtained, and the size of the capacitance correction area 450 corresponding to this correction value is set.
  • the initial state of the present embodiment is a state of 60% humidity, but it is optional.
  • the central portion of the upper electrode film 13 of the sensor unit 20 is left solid with the size of the capacitance correction area 450 set above, and the height of the center of the capacitance correction area 450 is high.
  • a large number of openings ⁇ for exposing the molecular moisture sensitive film 12 are formed by dry etching, for example.
  • openings ⁇ for exposing the polymer moisture sensitive film 12 are formed in the upper electrode film 13 of the reference portion 30 in the vertical and horizontal directions in FIG.
  • the opening ⁇ formed outside the capacitance correction area 450 of the upper electrode film 13 of the sensor unit 20 is the same as the opening ⁇ formed at the same position of the upper electrode film 13 of the reference unit 30.
  • the area of the upper electrode film 13 of the sensor unit 20 facing the lower electrode film 311 is increased or decreased according to the size of the solid film shaped capacitance correction area 450 having no opening, and the sensor capacitance C20 is changed.
  • the upper electrode film 13 on the side where the sensor portion 20 is obtained from the parallel plate structure by the polymer moisture sensitive film 12 and the lower electrode film 311 and the opening ⁇ is covered with the moisture impermeable protective film 14, the polymer moisture sensitive
  • the reference portion 30 is obtained from the parallel plate structure of the film 12 and the lower electrode film 311, and the capacitive humidity sensor 400 of FIGS. 14 and 15 is completed.
  • the present invention is applicable to a humidity sensor for environmental measurement.

Abstract

Provided are a capacitive humidity sensor capable of reducing the variations of the capacity difference between a sensor section and a reference section, and a manufacturing method therefor. The capacitive humidity sensor which comprises the sensor section, the electrostatic capacity of which changes in accordance with humidity and the reference section, the electrostatic capacity of which remains unchanged regardless of the humidity, and which converts the capacity difference between the sensor section and the reference section into a voltage and outputs the voltage, wherein the sensor section and the reference section are configured in the same parallel plate structure in which a polymer humidity sensitive film, the permittivity of which changes in accordance with humidity is sandwiched between a lower electrode film and an upper electrode film, wherein the sensor section induces the exposure of the polymer humidity sensitive film via one or more openings provided to the upper electrode film, and wherein the reference section covers the polymer humidity sensitive film with at least one of the upper electrode film or a moisture-impermeable protective film formed on the upper electrode film. The upper and lower electrode films, and the polymer humidity sensitive film are in a pattern shape in which the reference section and the sensor section are mirror-reversed to each other. Furthermore, a capacity correction area with no opening is provided in the center of the upper electrode film of the sensor section, and the initial capacity value of the sensor section is corrected in accordance with the size of the capacity correction area.

Description

容量型湿度センサ及びその製造方法Capacitive humidity sensor and method of manufacturing the same
　本発明は、高分子感湿膜を誘電体とした容量型湿度センサ及びその製造方法に関する。 The present invention relates to a capacitive humidity sensor using a polymer moisture sensitive film as a dielectric and a method of manufacturing the same.
　湿度変化測定に用いられる湿度センサには、湿度（吸着した水分量）に応じて誘電率が変化する高分子感湿膜を誘電体とした静電容量型の湿度センサがある。このタイプは、従来一般に、湿度に応じて静電容量が変化するセンサ部と湿度によらず一定の静電容量を保持する基準部を備え、センサ部と基準部の容量差分を電圧に変換して出力する。センサ部は、櫛歯電極の上に窒化シリコン膜と高分子材料からなる感湿膜とを形成した積層構造を有し、基準部は櫛歯電極の上に窒化シリコン膜を形成した積層構造を有する。このような容量型湿度センサは、例えば特許文献１に記載されている。 Humidity sensors used for humidity change measurement include capacitive humidity sensors in which a polymer moisture sensitive film whose dielectric constant changes in accordance with humidity (the amount of adsorbed water) is used as a dielectric. Conventionally, this type generally includes a sensor unit that changes its capacitance according to humidity and a reference unit that holds a constant capacitance regardless of humidity, and converts the capacitance difference between the sensor unit and the reference unit into a voltage. Output. The sensor unit has a laminated structure in which a silicon nitride film and a moisture sensitive film made of a polymer material are formed on a comb electrode, and the reference unit is a laminated structure in which a silicon nitride film is formed on the comb electrode Have. Such a capacitive humidity sensor is described, for example, in Patent Document 1.
特開２００６－５８０８４号公報JP, 2006-58084, A
　上記従来構造では、センサ部と基準部において、高分子感湿膜の有無により櫛歯電極上の膜構成（膜全体としての誘電率）が異なることから、櫛歯電極の設計（対数や交差幅）が同一ではなく煩雑化している。このため、高分子感湿膜の膜厚や熱処理加工のばらつきによりセンサ部の静電容量が個体毎にばらつき、センサ部と基準部の容量差分（センサ出力）がばらついていた。また、センサ部と基準部では、高分子感湿膜の有無により静電容量の温度依存性が異なるため、容量差分の温度依存性が生じる。この容量差分のばらつきや温度依存性は、湿度センサの測定誤差であるから、可能な限りなくしたい。特許文献１では、容量差分の温度依存性によるばらつきを補正するための機構を備えているが、構成が複雑になって好ましくない。 In the above-described conventional structure, the film configuration (dielectric constant of the entire film) on the comb electrode differs depending on the presence or absence of the polymer moisture sensitive film in the sensor portion and the reference portion. ) Is not identical but is complicated. For this reason, the electrostatic capacitance of the sensor unit varies from individual to individual due to variations in the film thickness of the polymer moisture sensitive film and the heat treatment process, and the capacitance difference (sensor output) between the sensor unit and the reference unit varies. In addition, since the temperature dependency of the capacitance differs depending on the presence or absence of the polymer moisture sensitive film in the sensor unit and the reference unit, the temperature dependency of the capacitance difference is generated. Since this variation in capacitance difference and temperature dependency are measurement errors of the humidity sensor, it is desirable to eliminate them as much as possible. In patent document 1, although the mechanism for correct | amending the dispersion | variation by the temperature dependence of a capacity | capacitance difference is provided, a structure becomes complexity and is unpreferable.
　本発明は、以上の問題意識に基づき、センサ部と基準部の容量差分のばらつき及び温度依存性を低減できる容量型湿度センサ及びその製造方法を得ることを目的とする。 An object of the present invention is to obtain a capacitive humidity sensor capable of reducing variations in temperature of a sensor unit and a reference unit, and a method of manufacturing the same, based on the above problem awareness.
　本発明は、センサ部と基準部に高分子感湿膜を上下電極で挟む平行平板構造を採用し、センサ部と基準部を同一の電極材料、誘電材料により同一工程で形成すれば、構造や製造工程の違いに起因していた容量差分のばらつきが抑えられ、かつ、センサ部の静電容量と基準部の静電容量が同じ温度特性を持つので容量差分の温度依存性を小さくできることに着眼して完成されたものである。 The present invention adopts a parallel plate structure in which a polymer moisture sensitive film is sandwiched between upper and lower electrodes in the sensor part and the reference part, and the sensor part and the reference part are formed in the same process using the same electrode material and dielectric material. The variation in the capacitance difference caused by the difference in the manufacturing process is suppressed, and the capacitance of the sensor unit and the capacitance of the reference portion have the same temperature characteristics, so the temperature dependency of the capacitance difference can be reduced. Was completed.
　すなわち、本発明は、湿度に応じて静電容量が変化するセンサ部と湿度にかかわらず静電容量が変化しない基準部を同一基板上に備え、該センサ部と基準部の容量差分を電圧に変換して出力する容量型湿度センサにおいて、センサ部と基準部は、湿度に応じて誘電率が変化する高分子感湿膜を下部電極膜と上部電極膜で挟んだ同一の平行平板構造を有していること、センサ部では、上部電極膜に高分子感湿膜を露出させる開口部が１以上設けられていること、及び、基準部では、上部電極膜の上に非透湿保護膜が形成され、該上部電極膜及び非透湿保護膜の少なくとも一方により高分子感湿膜が覆われていることを特徴としている。 That is, according to the present invention, a sensor unit whose capacitance changes according to humidity and a reference unit whose capacitance does not change regardless of humidity are provided on the same substrate, and the capacitance difference between the sensor unit and the reference unit is a voltage. In the capacitive humidity sensor that converts and outputs, the sensor unit and the reference unit have the same parallel plate structure in which the polymer moisture sensitive film whose dielectric constant changes according to the humidity is sandwiched between the lower electrode film and the upper electrode film. In the sensor section, the upper electrode film is provided with at least one opening for exposing the polymer moisture sensitive film, and in the reference section, the moisture impermeable protective film is formed on the upper electrode film. It is characterized in that the polymer moisture sensitive film is covered with at least one of the upper electrode film and the moisture impermeable protective film.
　基準部の上部電極膜には、センサ部の上部電極膜に設けた１以上の開口部と同一の開口部が設けられていてもよい。この場合、各開口部の下に位置する高分子感湿膜は、上部電極膜の上に形成した非透湿保護膜で覆う。 The upper electrode film of the reference portion may be provided with the same opening as the one or more openings provided in the upper electrode film of the sensor unit. In this case, the polymeric moisture sensitive film located under each opening is covered with a moisture impermeable protective film formed on the upper electrode film.
　センサ部の上部電極膜は、腐食防止のために、非透湿保護膜で覆われていることが実際的である。 It is practical that the upper electrode film of the sensor unit is covered with a moisture impermeable protective film to prevent corrosion.
　下部電極膜、高分子感湿膜及び上部電極膜は、センサ部と基準部でミラー反転したパターン形状をなしていることが好ましい。この態様によれば、センサ部と基準部の対称性が良くなり、センサ部と基準部での静電容量値を同一に合わせやすくなる。 It is preferable that the lower electrode film, the polymer moisture sensitive film, and the upper electrode film have a mirror-inverted pattern in the sensor portion and the reference portion. According to this aspect, the symmetry between the sensor unit and the reference unit is improved, and the electrostatic capacitance values in the sensor unit and the reference unit can be easily equalized.
　下部電極膜は、センサ部と基準部に共通に備えることができる。一方、高分子感湿膜及び上部電極膜は、センサ部と基準部に個別で備える。この場合、一端部が電極パッドに接続し、他端部がセンサ部と基準部の中間地点で下部電極膜に接続した下部電極配線を備えることが好ましい。センサ部と基準部の中間地点で下部電極膜から配線を引き出すことで、センサ部と基準部の対称性がより良好となる。 The lower electrode film can be provided commonly to the sensor unit and the reference unit. On the other hand, the polymer moisture sensitive film and the upper electrode film are separately provided in the sensor unit and the reference unit. In this case, it is preferable that the lower electrode wiring includes one end connected to the electrode pad and the other end connected to the lower electrode film at a midpoint between the sensor unit and the reference unit. By pulling out the wiring from the lower electrode film at the midpoint between the sensor unit and the reference unit, the symmetry of the sensor unit and the reference unit becomes better.
　センサ部の上部電極膜は、その中央部に位置させて、開口部を有さない容量補正エリアを備えていることが好ましい。この容量補正エリアの大きさを変更すれば、上部電極膜と下部電極膜の対向面積を容易に変更でき、所定条件によるセンサ部の静電容量値（初期容量値）の補正が容易になる。 It is preferable that the upper electrode film of the sensor unit has a capacitance correction area located at the central portion thereof and having no opening. By changing the size of the capacitance correction area, the facing area of the upper electrode film and the lower electrode film can be easily changed, and the correction of the capacitance value (initial capacitance value) of the sensor unit under predetermined conditions becomes easy.
　また本発明は、製造方法の態様によれば、基板上に同一の下部電極膜を同時に一対形成する工程と、この一対の下部電極膜の上に、湿度に応じて誘電率が変化する同一の高分子感湿膜を同時に形成する工程と、この一対の高分子感湿膜の上に、該高分子感湿膜を全面的に覆って下部電極膜と平行に対向する同一の上部電極膜を同時に形成する工程と、この一対の上部電極膜に、高分子感湿膜を露出させる１以上の開口部を同時に形成する工程と、一方の上部電極膜と該一方の上部電極膜の開口部の下に位置する高分子感湿膜を覆い、他方の上部電極膜と該他方の上部電極膜の開口部の下に位置する高分子感湿膜を露出させる非透湿保護膜を形成する工程とを有することを特徴としている。実際的には、電極腐食を防ぐため、非透湿保護膜によってさらに他方の上部電極膜を覆うことが好ましい。 Further, according to the embodiment of the present invention, according to the aspect of the manufacturing method, the step of simultaneously forming a pair of identical lower electrode films on a substrate and the same step of changing the dielectric constant according to humidity on the pair of lower electrode films. In the step of simultaneously forming a polymer moisture-sensitive film, and on the pair of polymer moisture-sensitive films, the same upper electrode film which covers the polymer moisture-sensitive film entirely and faces in parallel to the lower electrode film A step of simultaneously forming, a step of simultaneously forming at least one opening for exposing the polymer moisture-sensitive film in the pair of upper electrode films, an upper electrode film of one and an opening of the upper electrode film of one Forming a non-moisture-permeable protective film covering the lower polymer moisture-sensitive film and exposing the other upper electrode film and the polymer moisture-sensitive film located under the opening of the other upper electrode film; It is characterized by having. In practice, in order to prevent electrode corrosion, it is preferable to further cover the other upper electrode film with a moisture impermeable protective film.
　別の態様によれば、基板上に同一の下部電極膜を同時に一対形成する工程と、この一対の下部電極膜の上に、湿度に応じて誘電率が変化する同一の高分子感湿膜を同時に形成する工程と、この一対の高分子感湿膜の上に、該高分子感湿膜を覆って下部電極膜と平行に対向する同一の上部電極膜を同時に形成する工程と、この一対の上部電極膜を覆う非透湿保護膜を形成する工程と、一方の非透湿保護膜及び上部電極膜を削って、高分子感湿膜を露出させる１以上の開口部を形成する工程とを有することを特徴としている。 According to another aspect, the step of simultaneously forming a pair of identical lower electrode films on the substrate, and on the pair of lower electrode films, the same polymer moisture-sensitive film whose dielectric constant changes according to humidity. A step of forming simultaneously, a step of simultaneously forming an upper electrode film covering the polymer moisture sensitive film and facing in parallel to the lower electrode film on the pair of polymer moisture sensitive films; Forming a non-moisture permeable protective film covering the upper electrode film, and shaving one non-moisture permeable protective film and the upper electrode film to form one or more openings for exposing the polymer moisture sensitive film It is characterized by having.
　さらに別の態様によれば、基板上に、同一の下部電極膜を同時に一対形成する工程と、この一対の下部電極膜の上に、湿度に応じて誘電率が変化する同一の高分子感湿膜を同時に形成する工程と、この一対の高分子感湿膜の上に、該高分子感湿膜を覆って下部電極膜と平行に対向する同一の上部電極膜を同時に形成する工程と、一方の上部電極膜のみに、高分子感湿膜を露出させる開口部を１以上形成する工程と、一対の上部電極膜を覆う非透湿保護膜を形成する工程とを有することを特徴としている。 According to still another aspect, the step of simultaneously forming a pair of identical lower electrode films on a substrate, and the same polymer moisture sensitive material whose dielectric constant changes according to humidity on the pair of lower electrode films Simultaneously forming a film, and simultaneously forming, on the pair of polymer moisture-sensitive films, the same upper electrode film which covers the polymer moisture-sensitive films and faces in parallel to the lower electrode film. And forming a non-moisture-permeable protective film covering the pair of upper electrode films.
　上記製造方法において、一対の下部電極膜、一対の高分子感湿膜及び一対の上部電極膜は、互いにミラー反転したパターン形状で形成することが好ましい。一対の下部電極膜は、互いに接続した一体の共通電極膜で形成することができる。この場合、一端部が電極パッドに接続し、他端部が下部電極膜の中間位置に接続した下部電極配線を設けると、基準部とセンサ部の対称性が良くなる。 In the above manufacturing method, it is preferable that the pair of lower electrode films, the pair of polymer moisture sensitive films, and the pair of upper electrode films are formed in a pattern shape in which the mirrors are inverted to each other. The pair of lower electrode films can be formed of an integral common electrode film connected to each other. In this case, if the lower electrode wiring whose one end is connected to the electrode pad and the other end is connected to the middle position of the lower electrode film is provided, the symmetry between the reference part and the sensor part is improved.
　一方の上部電極膜の中央部に開口部を有さない容量補正エリアを設け、この容量補正エリアの大きさにより、特定湿度での該一方の上部電極膜、高分子感湿膜及び下部電極膜による静電容量値を補正することが好ましい。この態様によれば、湿度に応じて静電容量が変化するセンサ部の初期容量値を容易に調整でき、さらにセンサ部と基準部の容量差分のばらつきを低減可能である。 A capacity correction area having no opening is provided at the center of one upper electrode film, and the size of the capacity correction area allows the one upper electrode film, the polymer moisture sensitive film, and the lower electrode film at a specific humidity to be obtained. It is preferable to correct the capacitance value by. According to this aspect, it is possible to easily adjust the initial capacitance value of the sensor unit in which the capacitance changes in accordance with the humidity, and to reduce the variation in capacitance difference between the sensor unit and the reference unit.
　本発明によれば、センサ部と基準部が下部電極膜と上部電極膜の間に高分子感湿膜を介在させた同一の平行平板構造を有し、同一の電極材料及び誘電材料で同一の製造工程（ミラー反転パターン形成）により形成されるので、構造及び工程の違いによる容量ばらつきがなくなり、かつ、センサ容量と基準容量が同じ温度特性を有することになる。またセンサ部の上部電極膜に設けた容量補正エリアにより、センサ部の初期静電容量値を容易に調整できる。これにより、センサ部と基準部の容量差分のばらつき及び温度依存性を低減可能な容量型湿度センサ及びその製造方法が得られる。 According to the present invention, the sensor portion and the reference portion have the same parallel plate structure in which the polymer moisture sensitive film is interposed between the lower electrode film and the upper electrode film, and the same electrode material and dielectric material are used. Since it is formed by the manufacturing process (mirror inversion pattern formation), the capacity variation due to the difference in structure and process is eliminated, and the sensor capacity and the reference capacity have the same temperature characteristics. The initial capacitance value of the sensor unit can be easily adjusted by the capacitance correction area provided in the upper electrode film of the sensor unit. As a result, it is possible to obtain a capacitive humidity sensor capable of reducing the variation in temperature difference between the sensor unit and the reference unit and the temperature dependency, and a method of manufacturing the same.
本発明を適用した容量型湿度センサの主要構成を示すブロック図である。It is a block diagram which shows the main structures of the capacitive humidity sensor to which this invention is applied. 本発明の第１実施形態による容量型湿度センサのセンサ部と基準部の構造を示す断面図（図３のII－II線に沿う断面図）である。FIG. 6 is a cross-sectional view (a cross-sectional view taken along the line II-II in FIG. 3) showing the structure of the sensor portion and the reference portion of the capacitive humidity sensor according to the first embodiment of the present invention. 同容量型湿度センサのセンサ部と基準部の構造を示す平面図である。It is a top view which shows the structure of the sensor part of the same capacitive humidity sensor, and a reference | standard part. 本発明による容量型湿度センサの製造工程の一工程を説明する断面図である。It is sectional drawing explaining 1 process of the manufacturing process of the capacitive humidity sensor by this invention. 図４の次工程を示す断面図である。FIG. 5 is a cross-sectional view showing the next step of FIG. 4; 図５の次工程を示す断面図である。FIG. 6 is a cross-sectional view showing the next process of FIG. 5; 図６の次工程を示す断面図である。FIG. 7 is a cross-sectional view showing the next process of FIG. 6; 基準部の上部電極膜に開口部を設けない、本発明の第２実施形態による容量型湿度センサの断面図（図９のVIII－VIII線に沿う断面図）である。FIG. 10 is a cross-sectional view (cross-sectional view along the line VIII-VIII in FIG. 9) of the capacitive humidity sensor according to the second embodiment of the present invention in which the upper electrode film of the reference portion is not provided with an opening. 同容量型湿度センサの平面図である。It is a top view of the same capacitive humidity sensor. 本発明の第３実施形態による容量型湿度センサの平面図である。FIG. 7 is a plan view of a capacitive humidity sensor according to a third embodiment of the present invention. 同容量型湿度センサの断面図（図１０のXI－XI線に沿う断面図）である。FIG. 11 is a cross-sectional view of the same capacitive humidity sensor (cross-sectional view along the line XI-XI in FIG. 10). 同容量型湿度センサの配線接続を説明する模式図である。It is a schematic diagram explaining the wiring connection of the same capacitive humidity sensor. 同容量型湿度センサの配線接続の比較例を示す模式図である。It is a schematic diagram which shows the comparative example of the wiring connection of the same capacitance type humidity sensor. 本発明の第４実施形態による容量型湿度センサの平面図である。It is a top view of a capacitive humidity sensor by a 4th embodiment of the present invention. 同容量型湿度センサの断面図（図１４のXV－XV線に沿う断面図）である。FIG. 15 is a cross-sectional view of the same capacitive humidity sensor (cross-sectional view along the line XV-XV in FIG. 14).
　図１～図７は、本発明の第１実施形態を示している。図１は本発明による容量型湿度センサ１００の主要構成を示すブロック図、図２は容量型湿度センサ１００の断面図（図３のII－II線に沿う断面図）、図３は容量型湿度センサ１００のセンサ部２０と基準部３０に共通の平行平板構造を示す平面図である。 1 to 7 show a first embodiment of the present invention. FIG. 1 is a block diagram showing the main configuration of the capacitive humidity sensor 100 according to the present invention, FIG. 2 is a cross sectional view of the capacitive humidity sensor 100 (cross sectional view along line II-II in FIG. 3), FIG. It is a top view which shows the parallel plate structure common to the sensor part 20 and the reference part 30 of the sensor 100. FIG.
　容量型湿度センサ１００は、吸収または放出した水分量に応じて誘電率が変化する高分子感湿材料を誘電体とした高分子膜湿度センサである。この容量型湿度センサ１００は、表面が絶縁体で保護された例えばシリコンからなる基板１０上に、湿度によって静電容量Ｃ２０が変化するセンサ部２０と、湿度によらず一定の静電容量Ｃ３０を保持する基準部３０と、このセンサ部２０と基準部３０に電気的に接続し、該センサ部２０と基準部３０の容量差分ΔＣ（＝Ｃ２０－Ｃ３０）を電圧に変換して出力する回路部４０とを有している。回路部４０には、外部回路との接続用パッド４０ａが設けられている。図中の符号１０ａはＳｉ層、１０ｂは絶縁層である。 The capacitive humidity sensor 100 is a polymer film humidity sensor in which a polymer moisture sensitive material whose dielectric constant changes according to the amount of absorbed or released water is used as a dielectric. The capacitive humidity sensor 100 has a sensor unit 20 whose capacitance C20 changes with humidity and a constant capacitance C30 regardless of humidity on a substrate 10 made of, for example, silicon whose surface is protected by an insulator. A reference unit 30 to be held and a circuit unit electrically connected to the sensor unit 20 and the reference unit 30, and converting a capacitance difference ΔC (= C20-C30) between the sensor unit 20 and the reference unit 30 into a voltage and outputting it And 40. The circuit unit 40 is provided with a connection pad 40 a for connection to an external circuit. In the figure, reference numeral 10a is a Si layer, and 10b is an insulating layer.
　センサ部２０と基準部３０は、同一の電極材料及び誘電材料（高分子感湿材料）を用いて同一のプロセスで形成された下部電極膜１１、高分子感湿膜１２及び上部電極膜１３からなる同一の平行平板構造（図２、図３）を有している。 The sensor unit 20 and the reference unit 30 are formed of the lower electrode film 11, the polymer moisture sensitive film 12, and the upper electrode film 13 formed by the same process using the same electrode material and dielectric material (polymer moisture sensitive material). Have the same parallel plate structure (FIG. 2, FIG. 3).
　下部電極膜１１は、その平面形状が矩形状をなし、基板１０上に均一の膜厚で形成されている。高分子感湿膜１２は、ポリイミドからなり、下部電極膜１１の上に均一の膜厚で積層形成されている。図３では高分子感湿膜１２にハッチングを付して示してある。上部電極膜１３は、下部電極膜１１と同様にその平面形状が矩形状をなし、高分子感湿膜１２の上に均一の膜厚で形成されている。下部電極膜１１と上部電極膜１３は、例えばＡｌ、Ｔａ、Ｔｉ、ＮｉＦｅ、Ｎｉ等の電極材料からなる。下部電極膜１１と上部電極膜１３の間隔ｄは高分子感湿膜１２の膜厚に等しく、下部電極膜１１と上部電極膜１３の間に蓄積される静電容量Ｃは、高分子感湿膜１２の誘電率ε、下部電極膜１１と上部電極膜１３の間隔ｄと対向面積Ｓで決定される（Ｃ＝εＳ／ｄ）。図示実施形態では、高分子感湿膜１２が基板１０から下部電極膜１１の一端部を覆って該下部電極膜１１上に位置し、上部電極膜１３が基板１０から高分子感湿膜１２の一端部を覆って該高分子感湿膜１２上に位置するように下部電極膜１１に対して高分子感湿膜１２と上部電極膜１３の平面位置をずらしてあるが、下部電極膜１１と高分子感湿膜１２と上部電極膜１３の平面位置を一致させて、下部電極膜１１の上にのみ高分子感湿膜１２及び上部電極膜１３を設ける構造としても、高分子感湿膜１２が下部電極膜１１を覆うように設けられる構造としてもよい。 The lower electrode film 11 has a rectangular planar shape, and is formed on the substrate 10 with a uniform film thickness. The polymer moisture sensitive film 12 is made of polyimide and is laminated on the lower electrode film 11 with a uniform film thickness. In FIG. 3, the polymer moisture sensitive film 12 is shown hatched. The upper electrode film 13 has a rectangular planar shape in the same manner as the lower electrode film 11 and is formed on the polymer moisture sensitive film 12 with a uniform film thickness. The lower electrode film 11 and the upper electrode film 13 are made of an electrode material such as, for example, Al, Ta, Ti, NiFe, Ni or the like. The distance d between the lower electrode film 11 and the upper electrode film 13 is equal to the film thickness of the polymer moisture sensitive film 12, and the capacitance C accumulated between the lower electrode film 11 and the upper electrode film 13 is the polymer moisture sensitive It is determined by the dielectric constant ε of the film 12, the distance d between the lower electrode film 11 and the upper electrode film 13, and the facing area S (C = εS / d). In the illustrated embodiment, the polymer moisture sensitive film 12 covers one end of the lower electrode film 11 from the substrate 10 and is positioned on the lower electrode film 11, and the upper electrode film 13 is formed of the polymer moisture sensitive film 12 from the substrate 10. The planar position of the polymer moisture sensitive film 12 and the upper electrode film 13 is shifted with respect to the lower electrode film 11 so as to cover the one end portion and be located on the polymer moisture sensitive film 12. Even when the polymer moisture sensitive film 12 and the upper electrode film 13 are provided only on the lower electrode film 11 by aligning the planar positions of the polymer moisture sensitive film 12 and the upper electrode film 13, the polymer moisture sensitive film 12 is May be provided to cover the lower electrode film 11.
　上部電極膜１３には、高分子感湿膜１２を露出させる開口部αが多数設けられている。多数の開口部αは、下部電極膜１１と対向する領域に左右上下方向に所定間隔をあけて並び、平面矩形状をなしている。この開口部αの数、平面形状及び形成位置は任意である。 The upper electrode film 13 is provided with a large number of openings α for exposing the polymer moisture sensitive film 12. The large number of openings α are arranged at predetermined intervals in the left and right and up and down directions in a region facing the lower electrode film 11, and have a planar rectangular shape. The number, planar shape and formation position of the openings α are arbitrary.
　基準部３０では、雰囲気との水分授受を遮断する非透湿保護膜１４が上部電極膜１３の上に形成されており、この非透過保護膜１４によって上部電極膜１３の開口部αが覆われている。非透湿保護膜１４は、例えば窒化シリコン膜（ＳｉＮｘ膜）やＳｉＯ2膜、Ａｌ2Ｏ3／ＳｉＯ2積層膜、ＳｉＯ2／ＳｉＮ積層膜からなる。高分子感湿膜１２は、上部電極膜１３及び非透湿保護膜１４により覆われて雰囲気に曝されないので、雰囲気中の湿度（水分量）が変化しても該高分子感湿膜１２中の水分量は変化せず、誘電率εも変化しない。これにより、下部電極膜１１と上部電極膜１３の間には一定の静電容量Ｃ３０が保持される。以下の説明では、基準部３０の下部電極膜１１と上部電極膜１３の間に蓄積される静電容量を基準容量Ｃ３０ということにする。 In the reference portion 30, the moisture impermeable protective film 14 for blocking the exchange of water with the atmosphere is formed on the upper electrode film 13, and the aperture α of the upper electrode film 13 is covered with the nonpermeable protective film 14 ing. The moisture impermeable protective film 14 is made of, for example, a silicon nitride film (SiNx film), an SiO 2 film, an Al 2 O 3 / SiO 2 laminated film, or an SiO 2 / SiN laminated film. The polymer moisture sensitive film 12 is covered with the upper electrode film 13 and the moisture impermeable protective film 14 and is not exposed to the atmosphere, so even if the humidity (the amount of water) in the atmosphere changes, the polymer moisture sensitive film 12 is The amount of water does not change, nor does the dielectric constant .epsilon. Change. Thereby, a constant capacitance C30 is held between the lower electrode film 11 and the upper electrode film 13. In the following description, the capacitance accumulated between the lower electrode film 11 and the upper electrode film 13 of the reference portion 30 will be referred to as a reference capacitance C30.
　一方のセンサ部２０では、非透湿保護膜１４が上部電極膜１３のみを覆っていて、上部電極膜１３に設けた多数の開口部αは非透湿保護膜１４で覆われていない。高分子感湿膜１２は、この多数の開口部αを介して雰囲気に曝されるので、雰囲気中の湿度（水分量）に応じて吸収または放出する水分量が変化し、誘電率εが変化する。この結果、下部電極膜１１と上部電極膜１３間の静電容量Ｃ２０は変化する。以下の説明では、センサ部２０の下部電極膜１１と上部電極膜１３の間に蓄積される静電容量をセンサ容量Ｃ２０ということにする。 In one sensor unit 20, the moisture impermeable protective film 14 covers only the upper electrode film 13, and many openings α provided in the upper electrode film 13 are not covered with the moisture impermeable protective film 14. Since the polymer moisture sensitive film 12 is exposed to the atmosphere through the large number of openings α, the amount of water absorbed or released changes according to the humidity (the amount of water) in the atmosphere, and the dielectric constant ε changes Do. As a result, the capacitance C20 between the lower electrode film 11 and the upper electrode film 13 changes. In the following description, the capacitance accumulated between the lower electrode film 11 and the upper electrode film 13 of the sensor unit 20 is referred to as a sensor capacitance C20.
　回路部４０は、センサ容量Ｃ２０と基準容量Ｃ３０の差分ΔＣ（＝Ｃ２０－Ｃ３０）を電圧に変換して外部回路へ出力する。パッド４０ａを介して容量型湿度センサ１００に接続された外部回路は、該容量型湿度センサ１００の出力（容量差分ΔＣに対応する電圧）から湿度変化（相対湿度）を検知できる。 The circuit unit 40 converts the difference ΔC (= C20−C30) of the sensor capacitance C20 and the reference capacitance C30 into a voltage and outputs the voltage to an external circuit. An external circuit connected to the capacitive humidity sensor 100 via the pad 40a can detect a humidity change (relative humidity) from the output of the capacitive humidity sensor 100 (voltage corresponding to the capacitance difference ΔC).
　次に、図４～図７を参照し、容量型湿度センサ１００の製造方法について説明する。図４～図７は、容量型湿度センサ１００の製造工程を示す断面図である。 Next, with reference to FIGS. 4 to 7, a method of manufacturing the capacitive humidity sensor 100 will be described. 4 to 7 are sectional views showing manufacturing steps of the capacitive humidity sensor 100. As shown in FIG.
　先ず、図４に示すように、基板１０のＳｉ層１０ａを覆う絶縁層１０ｂ上に、同一の下部電極膜１１を一対形成する。ここで「同一の下部電極膜１１」とは、同一の電極材料を用いて同一のプロセスで形成される、同一の平面形状、膜構成及び膜厚を有する下部電極膜１１を意味する。下部電極膜１１の電極材料には、例えばＡｌ、Ｔａ、Ｔｉ、ＮｉＦｅ、Ｎｉを用いる。本実施形態では下部電極膜１１を平面矩形状に形成するが、下部電極膜１１の平面形状は任意である。この下部電極膜１１を形成する工程では、回路部４０の配線導体とパッド４０ａを同時に形成することができる。 First, as shown in FIG. 4, a pair of lower electrode films 11 identical to each other is formed on the insulating layer 10 b covering the Si layer 10 a of the substrate 10. Here, "the same lower electrode film 11" means the lower electrode film 11 having the same planar shape, film configuration, and film thickness, which is formed by the same process using the same electrode material. As an electrode material of the lower electrode film 11, for example, Al, Ta, Ti, NiFe, Ni are used. In the present embodiment, the lower electrode film 11 is formed in a flat rectangular shape, but the planar shape of the lower electrode film 11 is arbitrary. In the step of forming the lower electrode film 11, the wiring conductor of the circuit section 40 and the pad 40a can be formed simultaneously.
　次に、図５に示すように、一対の下部電極膜１１の上にそれぞれ、湿度に応じて誘電率が変化する同一の高分子感湿膜１２を形成する。ここでの「同一の高分子感湿膜１２」とは、同一の高分子感湿材料を用いて同一のプロセスで形成される、同一の平面形状、膜構成及び膜厚を有する高分子感湿膜１２を意味する。高分子感湿膜１２は、高分子感湿材料としてのポリイミドを下部電極膜１１の上に塗布し、このポリイミドを熱処理により硬化させることで形成できる。このとき高分子感湿膜１２の膜厚は、所望する下部電極膜１１と上部電極膜１３の対向間隔ｄと一致するように制御する。本実施形態では、下部電極膜１１の上だけでなく該下部電極膜１１の一端部から基板１０にかけても高分子感湿膜１２を形成してあるが、高分子感湿膜１２は下部電極膜１１を覆うように形成してもよい。 Next, as shown in FIG. 5, the same polymer moisture sensitive film 12 whose dielectric constant changes according to the humidity is formed on the pair of lower electrode films 11, respectively. Here, “the same polymer moisture sensitive film 12” refers to a polymer moisture sensitive film having the same planar shape, film configuration, and film thickness formed by the same process using the same polymer moisture sensitive material. The film 12 is meant. The polymer moisture sensitive film 12 can be formed by applying polyimide as a polymer moisture sensitive material on the lower electrode film 11 and curing the polyimide by heat treatment. At this time, the film thickness of the polymer moisture sensitive film 12 is controlled to match the desired facing distance d between the lower electrode film 11 and the upper electrode film 13. In the present embodiment, the polymer moisture sensitive film 12 is formed not only on the lower electrode film 11 but also from one end of the lower electrode film 11 to the substrate 10, but the polymer moisture sensitive film 12 is the lower electrode film 11 may be formed so as to cover it.
　続いて、図６及び図７に示すように、フォトリソグラフィ技術を用いて、一対の高分子感湿膜１２の上にそれぞれ、下部電極膜１１と平行に対向し、かつ、高分子感湿膜１２を露出させる開口部αを多数有する、同一の上部電極膜１３を形成する。ここで「同一の上部電極膜１３」とは、同一の電極材料を用いて同一のプロセスで形成される、同一の平面形状、膜構成及び膜厚を有する上部電極膜１３を意味する。上部電極膜１３の電極材料には、下部電極膜１１と同様に、例えばＡｌ、Ｔａ、Ｔｉ、ＮｉＦｅ、Ｎｉを用いる。本実施形態の上部電極膜１３は、平面矩形状をなし、高分子感湿膜１２の上のみでなく該高分子感湿膜１２の一端部から基板１０にかけても形成してあるが、高分子感湿膜１２の上（下部電極膜１１との対向領域）のみに形成してもよく、また、その平面形状も任意である。また、本実施形態では、各開口部αの平面形状を矩形状とし、上部電極膜１３が下部電極膜１１と対向する領域に多数の開口部αを上下左右方向に並べてあるが、開口部αの数、平面形状及び形成位置は適宜設定できる。 Subsequently, as shown in FIG. 6 and FIG. 7, the polymer moisture sensitive film is opposed on the pair of polymer moisture sensitive films 12 in parallel with the lower electrode film 11 by using the photolithography technology. The same upper electrode film 13 having a large number of openings α for exposing 12 is formed. Here, "the same upper electrode film 13" means the upper electrode film 13 having the same planar shape, film configuration and film thickness, which is formed by the same process using the same electrode material. As the electrode material of the upper electrode film 13, for example, Al, Ta, Ti, NiFe, and Ni are used similarly to the lower electrode film 11. The upper electrode film 13 of the present embodiment has a flat rectangular shape and is formed not only on the polymer moisture sensitive film 12 but also from one end of the polymer moisture sensitive film 12 to the substrate 10. It may be formed only on the moisture sensitive film 12 (area opposed to the lower electrode film 11), and its planar shape is also arbitrary. Further, in the present embodiment, the planar shape of each opening α is rectangular, and in the region where the upper electrode film 13 faces the lower electrode film 11, many openings α are arranged vertically and horizontally. The number, planar shape and formation position can be set appropriately.
　続いて、一方の上部電極膜１３と該上部電極膜１３に設けた多数の開口部αを覆い、かつ、他方の上部電極膜１３のみを覆って該上部電極膜１３に設けた開口部αは覆わない非透湿保護膜１４を形成する（図２）。非透湿保護膜１４は、雰囲気との水分授受を遮断する材料、例えば窒化シリコン膜（ＳｉＮｘ膜）やＳｉＯ2膜、Ａｌ2Ｏ3／ＳｉＯ2積層膜、ＳｉＯ2／ＳｉＮ積層膜で構成することが好ましい。この非透湿保護膜１４は、上述の他方の上部電極膜１３に設けた多数の開口部α及び回路部４０のパッド４０ａを除いて基板表面全体に形成することが実際的である。 Subsequently, the opening a provided in the upper electrode film 13 so as to cover one upper electrode film 13 and a large number of openings α provided in the upper electrode film 13 and cover only the other upper electrode film 13 is A moisture impermeable protective film 14 not covered is formed (FIG. 2). The moisture impermeable protective film 14 is made of a material that blocks moisture exchange with the atmosphere, such as a silicon nitride film (SiNx film), an SiO 2 film, an Al 2 O 3 / SiO 2 laminated film, or an SiO 2 / SiN laminated film. Is preferred. It is practical to form this moisture impermeable protective film 14 on the entire surface of the substrate except for the large number of openings α provided on the other upper electrode film 13 described above and the pads 40 a of the circuit section 40.
　以上の工程により、開口部αが非透湿保護膜１４で覆われていない側の上部電極膜１３、高分子感湿膜１２及び下部電極膜１１による平行平板構造からセンサ部２０が得られ、開口部αが非透湿保護膜１４で覆われた側の上部電極膜１３、高分子感湿膜１２及び下部電極膜１１による平行平板構造から基準部３０が得られ、図１～図３の容量型湿度センサ１００が完成する。 By the above steps, the sensor portion 20 is obtained from the parallel plate structure of the upper electrode film 13, the polymer moisture sensitive film 12 and the lower electrode film 11 on the side where the opening α is not covered with the moisture impermeable protective film 14. A reference portion 30 is obtained from a parallel plate structure of the upper electrode film 13, the polymer moisture sensitive film 12 and the lower electrode film 11 on the side where the opening α is covered with the moisture impermeable protective film 14, as shown in FIGS. The capacitive humidity sensor 100 is completed.
　上述のように容量型湿度センサ１００では、同一の電極材料及び誘電材料（高分子感湿材料）を用いた同一の製造工程（図４～図７）により形成した共通の平行平板構造（下部電極膜１１、高分子感湿膜１２及び上部電極膜１３）でセンサ部２０と基準部３０が形成されているので、高分子感湿膜１２の膜厚や熱処理のばらつきに起因するセンサ容量Ｃ２０及び基準容量Ｃ３０のばらつきは小さくなり、また、センサ容量Ｃ２０と基準容量Ｃ３０が同じ温度特性を有することからセンサ部２０と基準部３０の容量差分ΔＣの温度依存性も小さくなる。これにより、センサ部２０と基準部３０の容量差分ΔＣのばらつきは低減し、容量型湿度センサ１００の検出精度が向上する。 As described above, in the capacitive humidity sensor 100, a common parallel plate structure (lower electrode) formed by the same manufacturing process (FIGS. 4 to 7) using the same electrode material and dielectric material (polymer moisture sensitive material) Since the sensor unit 20 and the reference unit 30 are formed of the film 11, the polymer moisture sensitive film 12 and the upper electrode film 13), the sensor capacitance C20 and the film thickness of the polymer moisture sensitive film 12 and the variations in the heat treatment The variation of the reference capacitance C30 is reduced, and the temperature dependency of the capacitance difference ΔC between the sensor unit 20 and the reference portion 30 is also reduced because the sensor capacitance C20 and the reference capacitance C30 have the same temperature characteristic. Thereby, the variation in the capacitance difference ΔC between the sensor unit 20 and the reference unit 30 is reduced, and the detection accuracy of the capacitive humidity sensor 100 is improved.
　図８及び図９は、基準部３０側の上部電極膜１３に開口部を設けない第２実施形態の容量型湿度センサ２００を示す断面図及び平面図である。図９では、高分子感湿膜１２にハッチングを付して示した。 FIGS. 8 and 9 are a cross-sectional view and a plan view showing a capacitive humidity sensor 200 according to a second embodiment in which no opening is provided in the upper electrode film 13 on the reference portion 30 side. In FIG. 9, the polymer moisture sensitive film 12 is shown by hatching.
　容量型湿度センサ２００は、第１実施形態と同様にして一対の上部電極膜１３を形成した後、一対の上部電極膜１３を覆う非透湿保護膜１４を回路部４０のパッド４０ａを除いて基板表面全体に形成し、センサ部２０とする側の非透湿保護膜１４と上部電極膜１３を例えばドライエッチングにより削って高分子感湿膜１２を露出させる開口部αを多数形成することで、得られる。あるいは、第１実施形態と同様にして一対の上部電極膜１３を形成した後、一方の上部電極膜１３のみを例えばドライエッチングにより削って高分子感湿膜１２を露出させる開口部αを多数形成し、さらに、一対の上部電極膜１３を覆う非透湿保護膜１４を形成することで、得られる。 After forming the pair of upper electrode films 13 in the same manner as in the first embodiment, the capacitive humidity sensor 200 does not have the moisture impermeable protective film 14 covering the pair of upper electrode films 13 except for the pad 40 a of the circuit section 40. By forming on the entire surface of the substrate and etching the non-moisture permeable protective film 14 and the upper electrode film 13 on the side serving as the sensor unit 20 by, for example, dry etching, a large number of openings .alpha. ,can get. Alternatively, after forming the pair of upper electrode films 13 in the same manner as in the first embodiment, only one upper electrode film 13 is scraped by, for example, dry etching to form a large number of openings α for exposing the polymer moisture sensitive film 12 Further, by forming a non-moisture permeable protective film 14 covering the pair of upper electrode films 13, it is obtained.
　図１０～図１２は、センサ部２０と基準部３０に共通の下部電極膜３１１を備えた第３実施形態の容量型湿度センサ３００を示している。図１０は容量型湿度センサ３００の平面図、図１１は容量型湿度センサの断面図、図１２は下部電極膜１１と電極パッドの配線接続を示す模式図である。図１０は、非透湿保護膜１４を省略して示したもので、高分子感湿膜１２にハッチングを付してある。 FIGS. 10 to 12 show a capacitive humidity sensor 300 according to a third embodiment provided with the lower electrode film 311 common to the sensor unit 20 and the reference unit 30. FIG. 10 is a plan view of the capacitive humidity sensor 300, FIG. 11 is a sectional view of the capacitive humidity sensor, and FIG. 12 is a schematic view showing the wiring connection between the lower electrode film 11 and the electrode pad. In FIG. 10, the moisture impermeable protective film 14 is omitted, and the polymer moisture sensitive film 12 is hatched.
　容量型湿度センサ３００は、センサ部２０と基準部３０のそれぞれに、図９の破線で示す仮想中心線Ｘに関してミラー反転させたパターン形状で形成した下部電極膜３１１、高分子感湿膜１２及び上部電極膜１３を有している。仮想中心線Ｘは、センサ部２０と基準部３０の中間位置に設定してある。平行平板構造となる下部電極膜３１１、高分子感湿膜１２及び上部電極膜１３に上述のミラー反転パターンを用いることで、センサ部２０と基準部３０において該平行平板構造の形状対称性が良くなり、センサ容量Ｃ２０と基準容量Ｃ３０を一致させやすい。 The capacitive humidity sensor 300 has a lower electrode film 311, a polymer moisture sensitive film 12, and a lower electrode film 311 formed in a mirror-inverted pattern with respect to a virtual center line X indicated by a broken line in FIG. An upper electrode film 13 is provided. The virtual center line X is set at an intermediate position between the sensor unit 20 and the reference unit 30. By using the above-mentioned mirror reversal pattern for the lower electrode film 311, the polymer moisture sensitive film 12, and the upper electrode film 13 to be a parallel plate structure, the shape symmetry of the parallel plate structure in the sensor unit 20 and the reference unit 30 is good. As a result, the sensor capacitance C20 and the reference capacitance C30 can be easily matched.
　下部電極膜３１１は、センサ部２０から基準部３０にかけて設けた平面視矩形状の電極膜で、該センサ部２０と基準部３０に共通で備えられている。この下部電極膜３１１には、センサ部２０と基準部３０の中間位置から下部電極配線３２１が引き出され、この下部電極配線３２１を介して回路部４０の電極パッド４０ａに接続されている。別言すれば、下部電極配線３２１は、図１２に示されるように、一端部が回路部４０の電極パッド４０ａに接続し、他端部がセンサ部２０と基準部３０の中間位置（仮想中心線Ｘの位置）で下部電極膜３１１に接続している。このように下部電極配線３２１をセンサ部２０と基準部３０の中間位置から引き出せば、電気的にもセンサ部２０と基準部３０の対称性がよくなり、センサ容量Ｃ２０と基準容量Ｃ３０のばらつきを低減できる。下部電極配線３２１は、下部電極膜３１１と同一材料により、同時に形成できる。 The lower electrode film 311 is an electrode film having a rectangular shape in plan view provided from the sensor unit 20 to the reference unit 30, and is commonly provided to the sensor unit 20 and the reference unit 30. The lower electrode wiring 321 is drawn to the lower electrode film 311 from an intermediate position between the sensor unit 20 and the reference unit 30, and is connected to the electrode pad 40 a of the circuit unit 40 via the lower electrode wiring 321. In other words, as shown in FIG. 12, the lower electrode wiring 321 has one end connected to the electrode pad 40a of the circuit unit 40, and the other end intermediate between the sensor unit 20 and the reference unit 30 (virtual center The lower electrode film 311 is connected at the position of the line X). As described above, if the lower electrode wiring 321 is drawn out from an intermediate position between the sensor unit 20 and the reference unit 30, the symmetry of the sensor unit 20 and the reference unit 30 is improved electrically, and variations in the sensor capacitance C20 and the reference capacitance C30 are obtained. It can be reduced. The lower electrode wiring 321 can be formed simultaneously with the same material as the lower electrode film 311.
　高分子感湿膜１２及び上部電極膜１３は、センサ部２０と基準部３０で個別に備えられている。上部電極膜１３には、図１２に示すように、該上部電極膜１３と回路部４０の電極パッド４０ａを接続する上部電極配線３２３がそれぞれ設けられている。上部電極配線３２３は、一対の上部電極膜１３からそれぞれ一定の幅寸法で延長された配線パターンであって、その幅寸法が、センサ部２０と基準部３０で生じる寄生容量が同一になるように調整されている。これにより、寄生容量によるセンサ容量Ｃ２０と基準容量Ｃ３０のばらつきが低減されている。上部電極配線３２３は、上部電極膜１３と同一材料で、同時に形成できる。 The polymer moisture sensitive film 12 and the upper electrode film 13 are separately provided in the sensor unit 20 and the reference unit 30. On the upper electrode film 13, as shown in FIG. 12, an upper electrode wire 323 connecting the upper electrode film 13 and the electrode pad 40a of the circuit section 40 is provided. The upper electrode wiring 323 is a wiring pattern extended from the pair of upper electrode films 13 by a fixed width, so that the parasitic capacitances generated by the sensor unit 20 and the reference unit 30 become the same. It has been adjusted. Thereby, the variation of the sensor capacitance C20 and the reference capacitance C30 due to the parasitic capacitance is reduced. The upper electrode wiring 323 can be formed simultaneously with the same material as the upper electrode film 13.
　上記容量型湿度センサ３００は、次のように製造できる。 The capacitive humidity sensor 300 can be manufactured as follows.
　まず、たとえばシリコンからなる基板１０上に、センサ部と基準部に共通の下部電極膜３１１を形成する。このとき、下部電極膜３１１は、形成すべきセンサ部と基準部の中間位置に想定した仮想中心線Ｘに関してミラー反転させたパターン形状で形成する。本実施形態の下部電極膜３１１は仮想中心線Ｘに関してミラー反転させた平面視矩形状に形成してあるが、下部電極膜３１１の平面形状は仮想中心線Ｘに関してミラー反転していれば任意である。下部電極膜３１１の電極材料には例えばＡｌ、Ｔａ、Ｔｉ、ＮｉＦｅ、Ｎｉを用いる。この下部電極膜３１１を形成する工程では、回路部４０の配線導体（下部電極配線３２１）とパッド４０ａの少なくとも一方を同時に形成することができる。 First, the lower electrode film 311 common to the sensor portion and the reference portion is formed on the substrate 10 made of, for example, silicon. At this time, the lower electrode film 311 is formed in a pattern shape which is mirror-inverted with respect to a virtual center line X assumed at an intermediate position between the sensor portion to be formed and the reference portion. The lower electrode film 311 of the present embodiment is formed in a rectangular shape in plan view in which the mirror inversion is performed with respect to the virtual center line X, but the planar shape of the lower electrode film 311 is arbitrary as long as the mirror inversion is performed with respect to the virtual center line X is there. For example, Al, Ta, Ti, NiFe, and Ni are used as an electrode material of the lower electrode film 311. In the step of forming the lower electrode film 311, at least one of the wiring conductor (lower electrode wiring 321) of the circuit section 40 and the pad 40a can be simultaneously formed.
　次に、下部電極膜１１の上に、湿度に応じて誘電率が変化する高分子感湿膜１２を、仮想中心線Ｘに関してミラー反転させた平面視矩形状で一対形成する。一対の高分子感湿膜１２の平面形状は、仮想中心線Ｘに関してミラー反転していれば任意である。この高分子感湿膜１２は、高分子感湿材料としてのポリイミドを下部電極膜１１の上に塗布し、このポリイミドを熱処理により硬化させることで形成できる。このとき高分子感湿膜１２の膜厚は、所望する下部電極膜１１と上部電極膜１３の対向間隔ｄと一致するように制御する。本実施形態では、下部電極膜１１の上だけでなく該下部電極膜１１の一端部から基板１０にかけても高分子感湿膜１２を形成してあるが、高分子感湿膜１２は下部電極膜１１の上のみに形成してもよい。 Next, on the lower electrode film 11, a pair of the polymer moisture sensitive films 12 whose dielectric constant changes according to the humidity is formed in a rectangular shape in plan view with mirror inversion with respect to the virtual center line X. The planar shapes of the pair of polymer moisture sensitive films 12 are arbitrary as long as they mirror-invert with respect to the virtual center line X. The high molecular weight moisture sensitive film 12 can be formed by applying polyimide as a high molecular weight moisture sensitive material on the lower electrode film 11 and curing the polyimide by heat treatment. At this time, the film thickness of the polymer moisture sensitive film 12 is controlled to match the desired facing distance d between the lower electrode film 11 and the upper electrode film 13. In the present embodiment, the polymer moisture sensitive film 12 is formed not only on the lower electrode film 11 but also from one end of the lower electrode film 11 to the substrate 10, but the polymer moisture sensitive film 12 is the lower electrode film It may be formed only on 11.
　続いて、フォトリソグラフィ技術を用いて、一対の高分子感湿膜１２の上に、下部電極膜３１１と平行に対向し、かつ、高分子感湿膜１２を露出させる開口部αを多数有する上部電極膜１３を、仮想中心線Ｘに関してミラー反転させた高分子感湿膜１２よりも小さな平面視矩形状で一対形成する。一対の上部電極膜１３の平面形状は、仮想中心線Ｘに関してミラー反転していれば任意である。本実施形態では、各開口部αの平面形状を矩形状とし、上部電極膜１３が下部電極膜１１と対向する領域に多数の開口部αを上下左右方向に並べてあるが、開口部αの数、平面形状及び形成位置は適宜設定できる。上部電極膜１３の電極材料には、下部電極膜１１と同様に、例えばＡｌ、Ｔａ、Ｔｉ、ＮｉＦｅ、Ｎｉを用いる。この上部電極膜１３を形成する工程では、回路部４０の配線導体（上部電極配線３２３）とパッド４０ａの少なくとも一方を同時に形成することができる。 Subsequently, using photolithographic technology, an upper portion having a large number of openings α facing the lower electrode film 311 in parallel and exposing the polymer moisture sensitive film 12 on the pair of polymer moisture sensitive films 12 The electrode films 13 are formed in a pair in a rectangular shape in plan view smaller than the polymer moisture-sensitive film 12 mirror-inverted with respect to the virtual center line X. The planar shape of the pair of upper electrode films 13 is arbitrary as long as mirror inversion is performed with respect to the virtual center line X. In the present embodiment, the planar shape of each opening α is rectangular, and a large number of openings α are arranged in the upper, lower, left, and right directions in the region where the upper electrode film 13 faces the lower electrode film 11. The planar shape and the formation position can be set as appropriate. As the electrode material of the upper electrode film 13, for example, Al, Ta, Ti, NiFe, and Ni are used similarly to the lower electrode film 11. In the step of forming the upper electrode film 13, at least one of the wiring conductor (upper electrode wiring 323) of the circuit section 40 and the pad 40a can be simultaneously formed.
　続いて、一方の上部電極膜１３と該上部電極膜１３に設けた多数の開口部αを覆い、かつ、他方の上部電極膜１３のみを覆って該上部電極膜１３に設けた開口部αは覆わない非透湿保護膜１４を形成する。非透湿保護膜１４は、雰囲気との水分授受を遮断する材料、例えば窒化シリコン膜（ＳｉＮｘ膜）やＳｉＯ2膜、Ａｌ2Ｏ3／ＳｉＯ2積層膜、ＳｉＯ2／ＳｉＮ積層膜で構成することが好ましい。この非透湿保護膜１４は、上述の他方の上部電極膜１３に設けた多数の開口部α及び回路部４０のパッド４０ａを除いて基板表面全体に形成することが実際的である。 Subsequently, the opening a provided in the upper electrode film 13 so as to cover one upper electrode film 13 and a large number of openings α provided in the upper electrode film 13 and cover only the other upper electrode film 13 is A moisture impermeable protective film 14 not covered is formed. The moisture impermeable protective film 14 is made of a material that blocks moisture exchange with the atmosphere, such as a silicon nitride film (SiNx film), an SiO 2 film, an Al 2 O 3 / SiO 2 laminated film, or an SiO 2 / SiN laminated film. Is preferred. It is practical to form this moisture impermeable protective film 14 on the entire surface of the substrate except for the large number of openings α provided on the other upper electrode film 13 described above and the pads 40 a of the circuit section 40.
　以上の工程により、開口部αが非透湿保護膜１４で覆われていない側の上部電極膜１３、高分子感湿膜１２及び下部電極膜３１１による平行平板構造からセンサ部２０が得られ、開口部αが非透湿保護膜１４で覆われた側の上部電極膜１３、高分子感湿膜１２及び下部電極膜３１１による平行平板構造から基準部３０が得られ、図１０～図１２の容量型湿度センサ１００が完成する。センサ部２０の上部電極膜１３を覆う非透湿保護膜１４は省略可能であるが、非透湿保護膜１４は上部電極膜１３の腐食防止のために備えることが好ましい。 By the above steps, the sensor portion 20 is obtained from the parallel plate structure of the upper electrode film 13, the polymer moisture sensitive film 12 and the lower electrode film 311 on the side where the opening α is not covered with the moisture impermeable protective film 14. The reference portion 30 is obtained from a parallel plate structure of the upper electrode film 13, the polymer moisture sensitive film 12, and the lower electrode film 311 on the side where the opening α is covered with the moisture impermeable protective film 14 as shown in FIGS. The capacitive humidity sensor 100 is completed. Although the moisture impermeable protective film 14 covering the upper electrode film 13 of the sensor unit 20 can be omitted, the moisture impermeable protective film 14 is preferably provided for preventing the corrosion of the upper electrode film 13.
　図１３は、容量型湿度センサの配線接続の比較例を示す模式図である。下部電極配線３２１は、センサ部２０と基準部３０の一方（図１３ではセンサ部２０）から引き出す構造とすることもできる。 FIG. 13 is a schematic view showing a comparative example of the wiring connection of the capacitive humidity sensor. The lower electrode wiring 321 may be drawn out from one of the sensor unit 20 and the reference unit 30 (the sensor unit 20 in FIG. 13).
　図１４及び図１５は、センサ部２０の初期容量値を補正可能な第４実施形態の容量型湿度センサ４００の平面図及び断面図である。図１４は、非透湿保護膜１４を省略して示したもので、高分子感湿膜１２にハッチングを付してある。 FIGS. 14 and 15 are a plan view and a cross-sectional view of a capacitive humidity sensor 400 of the fourth embodiment capable of correcting the initial capacitance value of the sensor unit 20. FIG. In FIG. 14, the moisture-impermeable protective film 14 is omitted, and the polymer moisture-sensitive film 12 is hatched.
　湿度によって静電容量が変化するセンサ部と湿度によらず一定の静電容量を保持する基準部を備えた容量形湿度センサでは、その信頼性を確保するため、例えば湿度６０％のときを初期状態とし、この初期状態でのセンサ容量と基準容量が一致するようにセンサ部の静電容量値（初期容量値）を補正する必要がある。 In a capacitive humidity sensor provided with a sensor unit whose capacitance changes with humidity and a reference unit that holds a constant capacitance regardless of humidity, for example, when the humidity is 60%, the initial stage is to ensure its reliability. It is necessary to correct the electrostatic capacitance value (initial capacitance value) of the sensor unit so that the sensor capacitance in the initial state and the reference capacitance coincide with each other.
　容量型湿度センサ４００は、第３実施形態の容量型湿度センサ３００とほぼ同一であるが、センサ部２０の上部電極膜１３の中央部に開口部を有さない容量補正エリア４５０を設けた点で第３実施形態の容量型湿度センサ３００と異なる。このベタ膜状の容量補正エリア４５０を設けることで、該容量補正エリア４５０の大きさ（面積）に応じてセンサ部２０の上部電極膜１３の下部電極膜３１１に対向する面積が増減し、これによってセンサ容量Ｃ２０を補正できる。従来、センサ部２０の初期容量補正は上部電極膜１３の面積を変更することで行ってきたが、上部電極膜１３及び下部電極膜３１１の外周部ではそのエッジ効果により単位面積あたりの静電容量値が安定せず、目標とする初期容量値を得ることが難しかった。本実施形態のように上部電極膜１３の中央部に容量補正エリア４５０を設ければ、該中央部では単位面積あたりの静電容量値が安定していることから、センサ部２０の初期容量補正が格段に容易になる。 The capacitive humidity sensor 400 is substantially the same as the capacitive humidity sensor 300 of the third embodiment, but a capacitance correction area 450 having no opening at the center of the upper electrode film 13 of the sensor unit 20 is provided. This differs from the capacitive humidity sensor 300 of the third embodiment. By providing the solid film-like capacity correction area 450, the area facing the lower electrode film 311 of the upper electrode film 13 of the sensor unit 20 increases or decreases according to the size (area) of the capacity correction area 450. Thus, the sensor capacitance C20 can be corrected. Conventionally, the initial capacitance correction of the sensor unit 20 has been performed by changing the area of the upper electrode film 13, but in the outer peripheral portion of the upper electrode film 13 and the lower electrode film 311, the capacitance per unit area due to the edge effect The value was not stable, and it was difficult to obtain the target initial capacity value. If the capacitance correction area 450 is provided at the central portion of the upper electrode film 13 as in the present embodiment, the capacitance value per unit area is stable at the central portion. Is much easier.
　上記容量型湿度センサ４００は、次のように製造する。 The capacitive humidity sensor 400 is manufactured as follows.
　まず、第３実施形態と同様にして、一対の上部電極膜１３をベタ膜状で形成する。そして、一対の上部電極膜１３に多数の開口部αを形成する前段階で、初期状態におけるセンサ容量Ｃ２０と基準容量Ｃ３０を測定し、測定結果から初期状態でセンサ容量Ｃ２０と基準容量Ｃ３０が一致するのに必要な補正値（センサ部２０の初期容量値）を求め、この補正値に対応させた容量補正エリア４５０の大きさを設定する。本実施形態の初期状態は湿度６０％の状態としてあるが、任意である。 First, as in the third embodiment, the pair of upper electrode films 13 are formed in a solid film shape. Then, before forming a large number of openings α in the pair of upper electrode films 13, the sensor capacitance C20 and the reference capacitance C30 in the initial state are measured, and from the measurement results, the sensor capacitance C20 and the reference capacitance C30 match in the initial state A correction value (initial capacitance value of the sensor unit 20) required to do this is obtained, and the size of the capacitance correction area 450 corresponding to this correction value is set. The initial state of the present embodiment is a state of 60% humidity, but it is optional.
　続いて、図１４に示すように、上記設定した容量補正エリア４５０の大きさでセンサ部２０の上部電極膜１３の中央部をベタ膜状のまま残し、この容量補正エリア４５０の外周に、高分子感湿膜１２を露出させる多数の開口部αを例えばドライエッチングで形成する。同時に、基準部３０の上部電極膜１３に、高分子感湿膜１２を露出させる開口部αを図１４の上下左右方向に並べて形成する。センサ部２０の上部電極膜１３の容量補正エリア４５０外に形成した開口部αは、基準部３０の上部電極膜１３の同位置に形成した開口部αと同一である。開口部を有さないベタ膜状の容量補正エリア４５０の大きさに応じて、センサ部２０の上部電極膜１３の下部電極膜３１１と対向する面積が増減し、センサ容量Ｃ２０が変化する。 Subsequently, as shown in FIG. 14, the central portion of the upper electrode film 13 of the sensor unit 20 is left solid with the size of the capacitance correction area 450 set above, and the height of the center of the capacitance correction area 450 is high. A large number of openings α for exposing the molecular moisture sensitive film 12 are formed by dry etching, for example. At the same time, openings α for exposing the polymer moisture sensitive film 12 are formed in the upper electrode film 13 of the reference portion 30 in the vertical and horizontal directions in FIG. The opening α formed outside the capacitance correction area 450 of the upper electrode film 13 of the sensor unit 20 is the same as the opening α formed at the same position of the upper electrode film 13 of the reference unit 30. The area of the upper electrode film 13 of the sensor unit 20 facing the lower electrode film 311 is increased or decreased according to the size of the solid film shaped capacitance correction area 450 having no opening, and the sensor capacitance C20 is changed.
　続いて、第３実施形態と同様に非透湿保護膜１４を形成することで、容量補正エリア４５０を有し、開口部αが非透湿保護膜１４で覆われていない側の上部電極膜１３、高分子感湿膜１２及び下部電極膜３１１による平行平板構造からセンサ部２０が得られ、開口部αが非透湿保護膜１４で覆われた側の上部電極膜１３、高分子感湿膜１２及び下部電極膜３１１による平行平板構造から基準部３０が得られ、図１４及び図１５の容量型湿度センサ４００が完成する。 Subsequently, by forming the moisture impermeable protective film 14 in the same manner as in the third embodiment, the upper electrode film on the side having the capacitance correction area 450 and the opening α not covered with the moisture impermeable protective film 14 13. The upper electrode film 13 on the side where the sensor portion 20 is obtained from the parallel plate structure by the polymer moisture sensitive film 12 and the lower electrode film 311 and the opening α is covered with the moisture impermeable protective film 14, the polymer moisture sensitive The reference portion 30 is obtained from the parallel plate structure of the film 12 and the lower electrode film 311, and the capacitive humidity sensor 400 of FIGS. 14 and 15 is completed.
　本願発明は、環境測定用の湿度センサに適用可能である。 The present invention is applicable to a humidity sensor for environmental measurement.
１００　容量型湿度センサ
　１０　基板
　１１　下部電極膜
　１２　高分子感湿膜
　１３　上部電極膜
　１４　非透湿保護膜
　２０　センサ部
　３０　基準部
　４０　回路部
　４０ａ　パッド
２００　容量型湿度センサ
３００　容量型湿度センサ
３１１　下部電極膜
３２１　下部電極配線
３２３　上部電極配線
４００　容量型湿度センサ
４５０　容量補正エリア
　　α　開口部 100 capacitive humidity sensor 10 substrate 11 lower electrode film 12 polymer moisture sensitive film 13 upper electrode film 14 moisture impermeable protective film 20 sensor unit 30 reference unit 40 circuit unit 40 a pad 200 capacitive humidity sensor 300 capacitive humidity sensor 311 lower portion Electrode film 321 Lower electrode wiring 323 Upper electrode wiring 400 Capacitive humidity sensor 450 Capacitance correction area α Opening

Claims (15)

  1. 湿度に応じて静電容量が変化するセンサ部と湿度にかかわらず静電容量が変化しない基準部を同一基板上に備え、該センサ部と基準部の容量差分を電圧に変換して出力する容量型湿度センサにおいて、
    　前記センサ部と前記基準部は、湿度に応じて誘電率が変化する高分子感湿膜を下部電極膜と上部電極膜で挟んだ同一の平行平板構造を有していること、
    　前記センサ部では、前記上部電極膜に、前記高分子感湿膜を露出させる開口部が１以上設けられていること、及び、
    　前記基準部では、前記上部電極膜の上に非透湿保護膜が形成され、該上部電極膜及び非透湿保護膜の少なくとも一方により前記高分子感湿膜が覆われていること、
    を特徴とする容量型湿度センサ。     A sensor unit whose capacitance changes according to humidity and a reference unit whose capacitance does not change regardless of humidity are provided on the same substrate, and a capacitance that converts the difference between the sensor unit and the reference unit into a voltage and outputs it Type humidity sensor,
    The sensor unit and the reference unit have the same parallel flat plate structure in which a polymer moisture sensitive film whose dielectric constant changes according to humidity is sandwiched between a lower electrode film and an upper electrode film.
    In the sensor unit, the upper electrode film is provided with one or more openings for exposing the polymer moisture sensitive film, and
    In the reference portion, a moisture impermeable protective film is formed on the upper electrode film, and the polymer moisture sensitive film is covered with at least one of the upper electrode film and the moisture impermeable protective film.
    Capacitive humidity sensor characterized by
  2. 請求の範囲第１項に記載の容量型湿度センサにおいて、前記基準部の上部電極膜には、前記センサ部の上部電極膜に設けた１以上の開口部と同一の開口部が設けられ、各開口部の下に位置する高分子感湿膜は前記非透湿保護膜で覆われている容量型湿度センサ。 In the capacitive humidity sensor according to claim 1, the upper electrode film of the reference portion is provided with the same opening as the one or more openings provided in the upper electrode film of the sensor portion. The capacitive humidity sensor, wherein a polymer moisture sensitive film located under the opening is covered with the non-moisture permeable protective film.
  3. 請求の範囲第１項または第２項に記載の容量型湿度センサにおいて、前記センサ部の上部電極膜は非透湿保護膜で覆われている容量型湿度センサ。 The capacitive humidity sensor according to claim 1 or 2, wherein the upper electrode film of the sensor unit is covered with a moisture impermeable protective film.
  4. 請求の範囲第１項ないし第３項のいずれか一項に記載の容量型湿度センサにおいて、前記下部電極膜、前記高分子感湿膜及び前記上部電極膜は、前記センサ部と前記基準部でミラー反転したパターン形状をなしている容量型湿度センサ。 The capacitive humidity sensor according to any one of claims 1 to 3, wherein the lower electrode film, the polymer moisture sensitive film, and the upper electrode film are formed by the sensor unit and the reference unit. Capacitive humidity sensor with mirror-inverted pattern shape.
  5. 請求の範囲第１項ないし第４項のいずれか一項に記載の容量型湿度センサにおいて、前記下部電極膜は、前記センサ部と前記基準部に共通に備えられ、前記高分子感湿膜及び前記上部電極膜は、前記センサ部と前記基準部に個別で備えられている容量型湿度センサ。 The capacitive humidity sensor according to any one of claims 1 to 4, wherein the lower electrode film is commonly provided to the sensor unit and the reference unit, and the polymer moisture sensitive film and the polymer moisture sensitive film The upper electrode film is a capacitive humidity sensor provided separately in the sensor unit and the reference unit.
  6. 請求の範囲第５項に記載の容量型湿度センサにおいて、一端部が電極パッドに接続し、他端部が前記センサ部と前記基準部の中間地点で前記下部電極膜に接続した下部電極配線を備えた容量型湿度センサ。 In the capacitive humidity sensor according to claim 5, the lower electrode wiring has one end connected to the electrode pad and the other end connected to the lower electrode film at a midpoint between the sensor unit and the reference unit. Capacitive humidity sensor equipped.
  7. 請求の範囲第１項ないし第６項のいずれか一項に記載の容量型湿度センサにおいて、前記センサ部の上部電極膜は、該上部電極膜の中央部に、前記開口部を有さない容量補正エリアを備えている容量型湿度センサ。 7. The capacitive humidity sensor according to any one of claims 1 to 6, wherein the upper electrode film of the sensor unit does not have the opening at a central portion of the upper electrode film. Capacitive humidity sensor with correction area.
  8. 基板上に、同一の下部電極膜を同時に一対形成する工程と、
    　この一対の下部電極膜の上に、湿度に応じて誘電率が変化する同一の高分子感湿膜を同時に形成する工程と、
    　この一対の高分子感湿膜の上に、該高分子感湿膜を覆って前記下部電極膜と平行に対向する同一の上部電極膜を同時に形成する工程と、
    　この一対の上部電極膜に、前記高分子感湿膜を露出させる１以上の開口部を同時に形成する工程と、
    　一方の上部電極膜と該一方の上部電極膜の開口部の下に位置する高分子感湿膜を覆い、前記他方の上部電極膜と該他方の上部電極膜の開口部の下に位置する高分子感湿膜を露出させる非透湿保護膜を形成する工程と、
    を有することを特徴とする容量型湿度センサの製造方法。     Forming a pair of identical lower electrode films simultaneously on the substrate;
    Simultaneously forming, on the pair of lower electrode films, the same polymer moisture sensitive film whose dielectric constant changes in accordance with humidity;
    Simultaneously forming, on the pair of polymer moisture sensitive films, the same upper electrode film that covers the polymer moisture sensitive films and faces in parallel with the lower electrode film;
    Simultaneously forming, in the pair of upper electrode films, one or more openings for exposing the polymer moisture sensitive film;
    A polymer moisture sensitive film located under the opening of one upper electrode film and the upper electrode film of the one, and a high located under the opening of the other upper electrode film and the other upper electrode film Forming a moisture impermeable protective film exposing the molecular moisture sensitive film;
    A method of manufacturing a capacitive humidity sensor, comprising:
  9. 請求の範囲第８項に記載の容量型湿度センサの製造方法において、前記非透湿保護膜によってさらに前記他方の上部電極膜を覆う容量型湿度センサの製造方法。 The method of manufacturing a capacitive humidity sensor according to claim 8, further comprising: covering the other upper electrode film with the moisture impermeable protective film.
  10. 基板上に、同一の下部電極膜を同時に一対形成する工程と、
    　この一対の下部電極膜の上に、湿度に応じて誘電率が変化する同一の高分子感湿膜を同時に形成する工程と、
    　この一対の高分子感湿膜の上に、該高分子感湿膜を覆って前記下部電極膜と平行に対向する同一の上部電極膜を同時に形成する工程と、
    　この一対の上部電極膜を覆う非透湿保護膜を形成する工程と、
    　一方の非透湿保護膜及び上部電極膜を削って、前記高分子感湿膜を露出させる１以上の開口部を形成する工程と、
    を有することを特徴とする容量型湿度センサの製造方法。     Forming a pair of identical lower electrode films simultaneously on the substrate;
    Simultaneously forming, on the pair of lower electrode films, the same polymer moisture sensitive film whose dielectric constant changes in accordance with humidity;
    Simultaneously forming, on the pair of polymer moisture sensitive films, the same upper electrode film that covers the polymer moisture sensitive films and faces in parallel with the lower electrode film;
    Forming a moisture impermeable protective film covering the pair of upper electrode films;
    Cutting one moisture impermeable protective film and the upper electrode film to form at least one opening for exposing the polymer moisture sensitive film;
    A method of manufacturing a capacitive humidity sensor, comprising:
  11. 基板上に、同一の下部電極膜を同時に一対形成する工程と、
    　この一対の下部電極膜の上に、湿度に応じて誘電率が変化する同一の高分子感湿膜を同時に形成する工程と、
    　この一対の高分子感湿膜の上に、該高分子感湿膜を覆って前記下部電極膜と平行に対向する同一の上部電極膜を同時に形成する工程と、
    　一方の上部電極膜のみに、前記高分子感湿膜を露出させる開口部を１以上形成する工程と、
    　前記一対の上部電極膜を覆う非透湿保護膜を形成する工程と、
    を有することを特徴とする容量型湿度センサの製造方法。     Forming a pair of identical lower electrode films simultaneously on the substrate;
    Simultaneously forming, on the pair of lower electrode films, the same polymer moisture sensitive film whose dielectric constant changes in accordance with humidity;
    Simultaneously forming, on the pair of polymer moisture sensitive films, the same upper electrode film that covers the polymer moisture sensitive films and faces in parallel with the lower electrode film;
    Forming at least one opening for exposing the polymer moisture sensitive film only in one of the upper electrode films;
    Forming a moisture impermeable protective film covering the pair of upper electrode films;
    A method of manufacturing a capacitive humidity sensor, comprising:
  12. 請求の範囲第８項ないし第１１項のいずれか一項に記載の容量型湿度センサの製造方法において、前記一対の下部電極膜、前記一対の高分子感湿膜及び前記一対の上部電極膜は、互いにミラー反転したパターン形状で形成する容量型湿度センサの製造方法。 The method for manufacturing a capacitive humidity sensor according to any one of claims 8 to 11, wherein the pair of lower electrode films, the pair of polymer moisture sensitive films, and the pair of upper electrode films are A method of manufacturing a capacitive humidity sensor, wherein the capacitive humidity sensor is formed in a pattern of mirror-inverted patterns.
  13. 請求の範囲第８項ないし第１２項のいずれか一項に記載の容量型湿度センサの製造方法において、前記一対の下部電極膜を、互いに接続した一体の共通電極膜で形成する容量型湿度センサの製造方法。 The method of manufacturing a capacitive humidity sensor according to any one of claims 8 to 12, wherein the pair of lower electrode films are formed of an integral common electrode film connected to each other. Manufacturing method.
  14. 請求の範囲第１３項に記載の容量型湿度センサの製造方法において、一端部が電極パッドに接続し、他端部が前記下部電極膜の中間位置に接続した下部電極配線を設ける容量型湿度センサの製造方法。 The method of manufacturing a capacitive humidity sensor according to claim 13, wherein the lower electrode wiring is provided with one end connected to the electrode pad and the other end connected to the middle position of the lower electrode film. Manufacturing method.
  15. 請求の範囲第８項ないし第１４項のいずれか一項に記載の容量型湿度センサの製造方法において、一方の上部電極膜の中央部に前記開口部を有さない容量補正エリアを設け、この容量補正エリアの大きさにより、特定湿度での該一方の上部電極膜、高分子感湿膜及び下部電極膜による静電容量値を補正する容量型湿度センサの製造方法。 A method of manufacturing a capacitive humidity sensor according to any one of claims 8 to 14, wherein a capacitance correction area not having the opening is provided at a central portion of one upper electrode film, A method of manufacturing a capacitive humidity sensor, which corrects the capacitance value of the one upper electrode film, the polymer moisture sensitive film and the lower electrode film at a specific humidity according to the size of a capacitance correction area.
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