JP2002328110A - Electrostatic capacity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic capacity sensor, in particular, a humidity detecting sensor, of which the drift deterioration is restrained even under an environment of a high temperature and a high humidity. SOLUTION: In this sensor, a sensor body 2 interposed with a polymer film 2 between a pair of electrodes 2A, 2C is arranged on one side face of a substrate 1 having at least one through hole 1A penetrated through vertically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitance sensor, and more particularly, to a capacitance sensor effective for use as a humidity detection sensor in a high-temperature and high-humidity environment.

[0002]

2. Description of the Related Art Humidity detection sensors using a polymer film as a moisture-sensitive material are roughly classified into two types: a type for measuring capacitance and a type for measuring electric resistance. Among these, those that measure humidity by measuring capacitance have good humidity responsiveness, small hysteresis, small humidity dependency of humidity sensitivity, and wide measurable humidity / temperature range. It has the feature.

A sensor of this type generally has the following structure. That is, on one surface of the substrate, a sensor body is formed by laminating a thin lower electrode, a polymer film having electrical insulation and moisture sensitivity, and a thin upper electrode having a porous structure in this order. In this structure, lead wires are drawn out from each of the electrode and the upper electrode. In that case, an electrically insulating insulating material having an appropriate strength is used as the substrate, thereby ensuring the strength of the entire sensor.

Therefore, in this sensor structure, the sensor body formed on the substrate has a parallel plate type capacitor structure. This sensor detects the humidity in the environment based on the following operation principle. When the sensor is placed in an environment of a relative humidity, water vapor gas (water molecules) in the environment passes through the upper electrode having a porous structure and reaches the surface of the polymer film located thereunder. It is occluded inside the polymer film.

[0005] The occlusion phenomenon in that case continues until an equilibrium state is formed with the relative humidity in the environment. And
After the equilibrium state is formed, occlusion of the vapor gas into the polymer film and desorption of the occluded gas from the polymer film progress, and eventually the polymer film is exposed to the relative humidity in the environment. A corresponding certain amount of water vapor gas is stored. By the way, the above-mentioned occlusion amount of water vapor gas in the polymer film is
It is proportional to the relative humidity in the environment. Further, the capacitance of the sensor body having the capacitor structure is proportional to the amount of water vapor stored in the polymer film.

[0006] Therefore, if each lead wire drawn from the upper electrode and the lower electrode is connected to an impedance analyzer and an output signal related to the capacitance of the sensor body is detected, the polymer film is detected based on the output signal. It is possible to measure the amount of water vapor stored in the air, that is, the relative humidity in the environment. Then, the actual humidity detection is performed as follows.

First, the moisture sensitivity of the assembled sensor is measured. That is, at a temperature of 25 ° C., the relative humidity is x ₀ ,
x _1, ... x _n reference environment to form a detection signal (capacitance) c ₀ of the sensor under the reference environment an impedance analyzer by placing sensors in each reference environment, c _1,
... measure c _n . Then, the relationship between the relative humidity and the detection signal: x ₀ vs c ₀ , x ₁ vs c ₁ ,... X _n vs c _n is grasped and stored in the measuring device.

Then, actual humidity detection is performed. That is, this sensor is arranged in the environment of the humidity measurement target, and the output signal at that time is detected. If the output signal is c _n
If so, the measuring device reads the relative humidity in the environment of the measurement object as _xn . This detection method can also be applied to molecules other than the above-described water vapor gas, for example, polar formaldehyde, acetone, alcohol, and the like.

[0009]

However, the capacitance measurement type humidity detection sensor has the following problems. That is, if the device is used for a long time in a high-temperature and high-humidity environment, the output signal (capacitance) corresponding to the true relative humidity in the environment is not an output signal (capacitance) corresponding to a relative humidity higher than the relative humidity. (Capacitance).

For example, even if the true relative humidity of the environment is x _n , the output signal of the sensor at that time is c _n + Δ
and the relative humidity of the environment is x
Instead of displaying as _n , it is displayed as x _n + Δx. Conversely, even if the output signal of the sensor is c _n , the true relative humidity of the environment is not x _n , but x _n + Δx
It is that it is.

[0011] Such a phenomenon is generally called drift deterioration of the sensor. The present invention relates to the above-described problem in the capacitance measurement type humidity detection sensor, namely,
It is an object of the present invention to provide a capacitance sensor having a structure designed to suppress the occurrence of drift deterioration.

[0012]

Means for Solving the Problems In the course of research for achieving the above-mentioned object, the present inventors have made the following considerations regarding the cause of drift deterioration in a capacitance measurement type humidity detection sensor. Was. (1) In general, a polymer film is composed of a skeleton formed by polycondensation of a polymer and a free volume that is three-dimensionally distributed in the skeleton in the form of micropores. .
And the occlusion phenomenon of the steam gas into the polymer film can be interpreted as a phenomenon in which the steam gas is trapped in the above-mentioned free volume portion.

Therefore, the fact that the sensor is in an equilibrium state with the relative humidity of the environment means that water vapor gas corresponding to the relative humidity is absorbed in the free volume of the polymer film,
In addition, it may be considered that equal amounts of occluded steam gas and desorbed steam gas enter and exit the free volume. (2) When this sensor is placed in a high-temperature, high-humidity environment, the polymer film swells. In this case, both the skeleton portion and the free volume portion of the polymer film expand, but if the polymer film is in an unconstrained state, the mutual ratio between the skeleton portion and the free volume portion after the expansion is the same as before the expansion. That is, it is almost the same as the state under the reference environment described above.

However, in this sensor, one film surface (lower surface) of the polymer film is fixed to the substrate via the lower electrode and is in a restrained state, so that the polymer film in the vicinity does not expand, Only the free volume expands. As a result, stress is accumulated in the polymer film, and at the same time, the relative proportion of the free volume in the polymer film increases as compared to before the thermal expansion.

(3) Such a state means that the amount of steam gas occluded in the free volume portion is larger than before the thermal expansion (that is, the state under the reference environment). Therefore, the capacitance measured in this state has a value larger than the capacitance measured under the reference environment by an amount corresponding to the increased dielectric constant of the steam gas. Conversely, even if the detection signal of the sensor in a high-temperature and high-humidity environment is c _n , it is not a signal corresponding to the relative humidity x _n measured in the reference environment, but is actually a relative humidity x _n + Δx. It is considered to mean the corresponding signal.

Based on the above considerations on drift degradation, the present inventors have found that if the sensor is constructed without the polymer film being restrained by the substrate, the stress accumulation and free expansion due to thermal expansion under a high temperature and high humidity environment can be achieved. With the idea that the increase in the relative proportion of the volume can be suppressed, and thus the drift degradation can be suppressed, the capacitance sensor of the present invention has been developed based on this idea.

That is, in the capacitance sensor of the present invention, the sensor main body having the polymer film interposed between the pair of electrodes is disposed on one surface of the substrate having at least one through hole penetrating in the thickness direction of the substrate. It is characterized by having been done. Specifically, the sensor main body is formed by laminating a lower electrode, a polymer film, and an upper electrode having a porous structure or a network structure in this order, or a capacitance sensor (referred to as a sensor A), or A capacitance sensor comprising a pair of electrodes erected at predetermined intervals on a surface of the substrate, and a polymer film disposed at least between the pair of electrodes. Sensor B) is provided.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The capacitance sensor according to the present invention will be described below in detail by taking a humidity detection sensor as an example. At first,
The sensor A will be described. First, an example A ₁ of the sensor A of the present invention in FIG. The sensor A ₁ is provided on a frame-shaped substrate 1 in which one through hole 1A penetrating in the thickness direction is formed at the center, so that the upper opening of the through hole 1A is closed. A sensor body 2 having a parallel plate capacitor structure in which an electrode 2A, a polymer film 2B, and an upper electrode 2C having a porous structure or a mesh structure are laminated in this order is arranged. Then, lead wires 3a and 3b are connected to ends of the lower electrode 2A and the upper electrode 2C using, for example, a conductive adhesive.

In the case of the sensor A ₁ , the capacitor area of the sensor main body 2 has a structure in which the through hole 1 A of the substrate 1 is closed and held in a hollow state. Therefore, the lower surface of the lower electrode 2A in the sensor body 2 is
A is in direct contact with the environment through A. The sensor A ₁ can be manufactured as follows. This will be described with reference to the drawings.

First, as shown in FIG. 2, a lower electrode 2A is formed by depositing an electrode material on a substrate 1 having a predetermined shape by, for example, a vacuum evaporation method or a sputtering method. The substrate 1 may be any substrate made of an electrically insulating material, for example, glass; quartz; silicon; ceramics such as silicon nitride, aluminum nitride, zirconia, and sialon; and substrates such as sapphire. be able to. Among them, the glass substrate is preferable from the viewpoint of cost and easy processing of the substrate described later.

The lower electrode 2A may be made of any material as long as it is made of a conductive material.
Pt, Cr, Au, Nb, Ru, Ti, Ta, Al,
W, C, Si, Ni, Ag, Pd, Cu, RuO ₂ , I
TO and the like. Of these, when assuming that the humidity measurement environment is a corrosive environment, A
It is preferably a corrosion-resistant material such as u, Pt, Ta, Nb, Cr, and Ti. Particularly, it is preferably Pt.

The thickness of the lower electrode 2A is not particularly limited, but is usually set to be about 0.02 to 1 μm. Subsequently, as shown in FIG. 3, the polymer film 2B is formed by burying the lower electrode 2A. This polymer film 2B
Any material may be used as long as it is electrically insulating and has moisture sensitivity. For example, polyimide, polysulfone, polyethersulfone, polyetherimide, polyether, polyamideimide, polyphenylene oxide, polycarbonate And organic polymer materials such as polymethyl methacrylate, polybutylene terephthalate, polyethylene terephthalate, polyethyl ether ketone, polyether ketone, cellulose acetate butyl and cellulose acetate, and cross-linked polymer materials.

Of these, crosslinked polyimides are preferred because they are less likely to deteriorate even in a corrosive environment and have good long-term stability of moisture sensitivity. Since the thickness of the polymer film 2B is inversely proportional to the capacitance of the manufactured sensor when the effective area of the upper and lower electrodes is fixed,
If the thickness is too large, the accuracy of the detection signal is reduced. On the other hand, if the thickness is too small, the homogeneity and insulation of the film are deteriorated, and the reliability of the detection signal obtained is reduced. For this reason, the film thickness is usually set to about 0.5 to 10 μm.

In forming the polymer film 2B, first, a resin liquid made of a predetermined material and adjusted to a predetermined viscosity is prepared. Then, the resin liquid is applied on the lower electrode at an appropriate temperature by, for example, a spin coating method. Next, the coating film is cured by, for example, drying at an appropriate temperature to obtain the desired polymer film 2B. In this process,
The final thickness of the polymer film is controlled by adjusting the applied thickness of the resin liquid.

Next, as shown in FIG.
The upper electrode 2C having a porous structure or a mesh structure is formed on B by, for example, a vacuum contact method or a sputtering method to form the sensor body 2 having a capacitor structure. As an electrode material used for forming the upper electrode 2C, for example, Cr, Au,
Pt, Nb, Ru, Ti, Ta, Al, W, C, Si,
Ni, Ag, Pd, Cu and the like can be mentioned. Of these, Cr is suitable because it has excellent corrosion resistance and tends to have a porous structure due to the generation of microcracks during electrode formation, thereby increasing the detection response of the sensor.

If the thickness of the upper electrode 2C is too large, the response speed to the humidity change in the environment starts to decrease. Conversely, if the thickness is too small, the electrode surface approaches an island-like structure and the conductivity as an electrode decreases. Therefore, the thickness is usually set to about 10 to 300 nm. Next, as shown in FIG. 5, a resist mask 4 is formed on the back surface of the substrate 1 by applying, for example, a photolithography technique to cover the surface other than where the through holes are to be formed.

Next, for the exposed surface 1B,
For example, inductively-coupled plasm
a: ICP) The substrate material up to the back surface of the lower electrode 2A is etched away by applying an etching method. as a result,
A through hole 1A as shown in FIG. 1 is formed in the substrate 1,
The back surface of the lower electrode 2A is exposed from the upper part. Finally, the end of the polymer film 2B is removed to expose the end surface of the lower electrode 2A, and the lead wire 3a is connected thereto, and the lead wire 3b is connected to the end of the upper electrode 2C. And Figure 1
Sensor A ₁ shown in is produced.

[0028] In the case of the sensor A _1, the sensor body 2 is held by the peripheral edge of the substrate 1, the lower electrode 2A in a capacitor structure located in the center portion is not fixed to the substrate 1, therefore, the capacitor The structure is in a state of being held hollow above the through hole 1A. Placing the sensor A ₁ in a high-temperature and high-humidity environment, the polymer film 2B is thermally expanded. However, since the sensor body 2 is held in the air via the lower electrode 2A without being restrained by the substrate 1, the restraint on the polymer film 2B is reduced, and the polymer film 2B is restrained.
B can move relatively freely following its thermal expansion.

Therefore, the stress accumulation in the polymer film 2B is reduced, and at the same time, the thermal expansion of the skeleton portion and the free volume portion proceeds while maintaining the ratio of both under the reference environment. Therefore, it is unlikely that the relative proportion of the free volume increases. Therefore, in the sensor A _1, drift deterioration in high-temperature and high-humidity environment is suppressed.

[0030] Figure 6 shows another sensor example A ₂ of the present invention. The case of the sensor A _2, have become partially exposed structure of the lower electrode 2A and the polymer film 2B from the upper portion of the through-hole 1A. In the sensor A _2, the sensor main body 2 a through hole 1
Because it is hollow holding on A, the stress accumulation in the polymer film 2B at similar thermal expansion to that of the sensor A ₁ is alleviated. In addition to that, since a part of the surface of the polymer film 2B is exposed in the environment, the excessively occluded water vapor gas due to the increase of the free volume due to the thermal expansion of the polymer film 2B is reduced. Therefore, the moisture sensitive property under the reference environment is easily maintained even under the high temperature and high humidity environment. Furthermore, since the polymer film 2B comes into contact not only from the upper electrode 2C side but also the water vapor gas from below, the time required for the polymer film 2B to be in equilibrium with the relative humidity of the environment is short, that is, the response of the sensor is improved Also has the effect of doing. In addition, responsiveness can be further improved by making the lower electrode 2A have a porous structure or a mesh structure.

When the sensor A ₁ is compared with the sensor A ₂ , the response of the sensor A ₁ is slower than that of the sensor A ₂ , but the upper opening of the through hole 1 A is closed by the lower electrode 2 A, and the response is higher. Since the molecular film 2B is protected from the environment,
The stability of the electrical characteristics is excellent. Each of the sensors A ₁ and A ₂ described above is a case where one through hole is formed in the substrate 1, but the present invention is not limited to this embodiment, and is shown in FIG. Substrate 1
May be a sensor in which a plurality of through holes 1A are formed. In that case, all of the upper opening of the through hole 1A may reach the back surface of the lower electrode 2A, or some may reach the back surface of the lower electrode and the rest may reach the back surface of the polymer film. Good. Further, as shown in FIG. 8, a sensor body 2 having a triangular shape in plan view may be held in a hollow state on one side of a frame-shaped substrate 1 in a cantilever state.

Next, an example of the sensor B of the present invention is shown in FIGS. FIG. 9 is a plan view of the sensor B, and FIG. 10 is a sectional view taken along line XX of FIG. In this sensor B, at least one pair of electrodes 2D and 2E as shown in FIG. 9 which is a plan view is provided on one surface of a substrate 1 having a through hole 1A in a comb-like shape. These electrodes 2D and 2E are erected substantially vertically at a predetermined interval from each other, and each is a planar electrode. Then, a resin liquid is applied to the surface of the substrate 1 and then cured, whereby the electrodes 2D and 2D are applied.
The structure is such that the polymer film 2B is interposed between E.

Therefore, since a sensor body having a single capacitor structure is formed by a pair of electrodes 2D and 2E and a polymer film 2B interposed therebetween, the polymer film 2
The change in capacitance due to moisture absorption of B can be extracted as a detection signal from the pair of electrodes 2D and 2E described above. In that case, the polymer film 2B in this sensor body
Shows a behavior different from that of the polymer film in the sensor A described above. That is, when the sensor B is placed in a high-temperature and high-humidity environment, the polymer film 2B tends to thermally expand.
The thermal expansion is suppressed by the electrodes 2D and 2E located on both sides. Accordingly, the polymer film 2B maintains the state under the reference environment, and eventually, the drift deterioration is suppressed.

Since the polymer film 2B comes into direct contact with the water vapor gas both from above and from below through the through hole 1A, the responsiveness of the sensor B becomes excellent.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Was prepared sensors A ₁ shown in manufacturing drawing 1 of the sensor as follows. Pt is deposited on a glass plate having a thickness of 0.5 mm by a vacuum evaporation method to form a lower electrode 2A having a thickness of 500 nm (FIG. 2). Heat treatment was performed at 300 ° C. to form a 5 μm-thick crosslinked polyimide film (polymer film) 2B (FIG. 3). Then, metal Cr was deposited on the crosslinked polyimide film by a sputtering method to form an upper electrode 2C having a thickness of 100 nm, and the sensor body 2 was disposed on one surface of a glass plate (FIG. 4).

Next, after applying a resist on the back surface of the glass plate, photolithography was performed to form a frame-shaped resist mask 4 on the edge of the back surface of the glass plate (FIG. 5). Then, using an ICP etching apparatus, a plate thickness portion from the back surface of the exposed glass plate to the lower electrode was removed by etching, and a structure in which the sensor main body 2 was held hollow by the glass plate was manufactured. Then, a part of the polyimide film 2B is removed to expose the end of the lower electrode 2A, and this end and the upper electrode 2C are exposed.
Of the Cu leads 3a at each end, to connect the 3b with a conductive adhesive, and a sensor A ₁ shown in FIG.

For comparison, a sensor was manufactured in which the sensor body 2 was disposed on one side of the glass plate without performing etching on the glass plate. This is referred to as a sensor A ₁ ′. 2. Measurement of Drift Degradation (1) First, a change value of the capacitance per 1% of relative humidity in each sensor is measured.

In each case, the temperature is 25 ° C. and the relative humidity is, for example, 10%, 20%, 30%, 40%, 50%, 60%,
Environments managed at nine levels of 70%, 80% and 90% are created, sensors are arranged in these environments, and the capacitance at that time is measured. The measurement was performed using an LCZ meter (measurement conditions:
(Frequency: 100 kHz, applied voltage: 1.0 V). The obtained measured value is plotted on the vertical axis, and the relative humidity is plotted on the horizontal axis. Since the measurement temperature is as low as 25 ° C., the relative humidity and the measured value (capacitance) are in a proportional relationship, and a straight line is obtained.

When the slope of this straight line is obtained, the obtained value means the amount of change in the capacitance measured by the sensor when the relative humidity changes by 1%, and that value is used for the sensor. It is uniquely determined by the type of polymer film. The unit is (capacitance / 1% relative humidity). The change values (a1) obtained for the sensors A ₁ and A ₁ ′ were both 0.2.

(2) Measurement of Drift Degradation As reference environments, an environment (I) at a temperature of 25 ° C. and a relative humidity of 10%, an environment (II) at a temperature of 25 ° C. and a relative humidity of 50%, a temperature of 25 ° C. and a relative humidity of 90% Environment (III) was set.
The sensors A ₁ and A ₁ ′ were placed in each environment, and the capacitance at that time was measured. Each of the sensors A ₁ and A ₁ ′ was 192 pF in the environment (I), 200 pF in the environment (II), and 208 pF in the environment (III).

Next, the sensors A ₁ and A ₁ ′ are set at a temperature of 40 ° C. and a relative humidity of 9 based on the environments (I), (II) and (III).
It was moved to a 0% high temperature and high humidity environment and left there. 200
After elapse of time, elapse of 600 hours, elapse of 1000 hours, the sensor is taken out, and immediately the original environment (I), (II),
Returning to (III), the capacitance was measured under the environment.

Then, using the obtained measured value (c) and the change value (a) of the capacitance per 1% relative humidity of each sensor, the c / a value was obtained as follows. . That is, in the case of environment (I): (capacitance at 10% relative humidity after standing in a high-temperature, high-humidity environment—capacitance at 10% relative humidity before standing in a high-temperature, high-humidity environment ) / A + 1
0 Environment (II): (Capacitance at 50% relative humidity after standing in a high-temperature, high-humidity environment-Capacitance at 50% relative humidity before standing in a high-temperature, high-humidity environment) / A + 5
0 Environment (III): (Capacity at 90% relative humidity after standing in a high temperature and high humidity environment-Capacitance at 90% relative humidity before leaving in an initial high temperature and high humidity environment) / A +
The above results are shown in FIG. 11 in the case of environment (I).
FIG. 12 shows the case of I), and FIG. 13 shows the case of environment (III).

(3) Evaluation In FIGS. 11 to 13, the value on the vertical axis at the zero point on the horizontal axis is the characteristic value relating to the capacitance of the sensor in the environment (I), the environment (II) or the environment (III). It is. This value is the same since the sensors A ₁ and A ₁ ′ both use the same type of polymer film.

However, when the sensors A ₁ and A ₁ ′ are left in a high-temperature and high-humidity environment, both exhibit the following behavior. For example, in FIG. 11, when measuring the capacitance to return the sensor A ₁ to 200 hours standing was later re environment (I), c / a values indicate about 10.5, but if the sensor A ₁ ' A c / a value of about 12.1 is shown. Before being left in a high-temperature and high-humidity environment, that is, considering that the c / a value in the environment (I) was 10.0 for both the sensor A ₁ and the sensor A ₁ ′, 200 The c / a value of the sensor A ₁ is about 0.5 (10.
5-10.0), and the c / a value of the sensor A ₁ ′ has increased by 1.6 (12.1 to 10.5).

The increase in the c / a value indicates that the amount of the steam gas occluded in the polymer film is larger than that in the environment (I). That is, the sensor A ₁ and the sensor A ₁ ′
In any of the above, if the polymer film is left for 200 hours in a high-temperature and high-humidity environment, its free volume increases due to thermal expansion of the polymer film, and the amount of water vapor absorbed increases. Even if it is returned, the occluded amount of water vapor gas in the polymer film is not restored to the original state, indicating that the increased water vapor gas remains in the polymer film without being desorbed. The result is an increase in the c / a value.

Accordingly, in FIG. 11, a sensor whose c / a value indicates a value more distant from the c / a value (reference value) in the environment (I), that is, the value farther from the value on the vertical axis at the zero point on the horizontal axis, Since the above-mentioned meaning that the residual amount of the steam gas is increased, the signal detected in the high-temperature and high-humidity environment is not a signal corresponding to the true relative humidity in the environment, but is higher than that. The signal corresponds to high relative humidity.

[0047] For this reason, when comparing the sensor A ₁ and sensor A ₁ 'in FIG. 11, the sensor A ₁ c / a
Although the value is larger than the reference value, the difference is smaller than that of the sensor A ₁ ′. That is, the sensor A ₁ is the drift degradation at high temperature and high humidity environment as compared with the sensor A ₁ 'is suppressed. This is because the polymer film used in the sensor A ₁ and the sensor A ₁ ′ are of the same type, but the sensor A ₁ has an effective structure in consideration of the fact that the sensor body has a hollow structure. The nature is clearly shown.

It is clear from FIGS. 12 and 13 that this sensor structure is more advantageous as the reference environment is set on the high humidity side.

[0049]

As is apparent from the above description, when the capacitance sensor of the present invention is used as a humidity detection sensor, it is unlikely to cause drift deterioration even in a high-temperature and high-humidity environment and has high reliability. Transmits humidity signal. This is because by providing a through hole that reaches the sensor main body on the substrate on which the sensor main body is arranged, the degree of freedom during thermal expansion of the polymer film of the sensor main body is ensured, and the stress accumulation of the polymer film is increased. This is the effect brought about by the structural design for relaxing.

Therefore, this sensor is effective for use in a field where it is necessary to form an extremely humid environment such as a humidity detection in a fuel cell or a facility horticulture field. Although the above description has been made for the case where the measurement target is the humidity in the environment, the capacitance sensor of the present invention is not limited to this. Any gas that changes the electric capacity can be used as a sensor that detects the gas.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example A1 of a sensor according to the present invention.

When manufacturing the Figure 2 sensor A _1, it is a cross-sectional view showing a state of forming a lower electrode on a substrate.

FIG. 3 is a cross-sectional view showing a state where a polymer film is formed.

FIG. 4 is a cross-sectional view showing a state where an upper electrode is formed.

FIG. 5 is a cross-sectional view showing a state where a resist mask is formed on the back surface of the substrate.

6 is a sectional view showing another example A ₂ of the sensor of the present invention.

FIG. 7 is a sectional view showing still another example of the sensor of the present invention.

FIG. 8 is a perspective view showing still another example of the sensor of the present invention.

FIG. 9 is a plan view showing another example B of the sensor of the present invention.

FIG. 10 is a sectional view taken along the line XX of FIG. 9;

FIG. 11 is a graph showing the relationship between the time during which the sensor is left in a high-temperature and high-humidity environment and the c / a value when the reference environment is at a temperature of 25 ° C. and a relative humidity of 10% (environment (I)). .

FIG. 12 is a graph showing the relationship between the time for which a sensor is left in a high-temperature and high-humidity environment and the c / a value when the reference environment is at a temperature of 25 ° C. and a relative humidity of 50% (environment (II)). .

FIG. 13 is a graph showing the relationship between the time during which the sensor is left in a high-temperature and high-humidity environment and the c / a value when the reference environment is at a temperature of 25 ° C. and a relative humidity of 90% (environment (III)). .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 1A Through-hole of substrate 1 2 Sensor main body 2A Lower electrode 2B Polymer film 2C Upper electrode 2D, 2E Plate electrode 3a, 3b Lead wire 4 Resist mask

Continued on the front page F term (reference) 2G060 AA01 AB02 AB19 AB21 AB22 AE19 AF03 AF06 AF10 AF11 AG08 AG11 BA09 BB10 HA02 HC10 HC19 HE03 JA01

Claims (3)

[Claims] 1. A static sensor wherein a sensor body having a polymer film interposed between a pair of electrodes is disposed on one surface of a substrate having at least one through hole penetrating in a thickness direction of the substrate. Capacitance sensor. 2. The capacitance sensor according to claim 1, wherein the sensor body is formed by laminating a lower electrode, a polymer film, and an upper electrode having a porous structure or a mesh structure in this order. 3. The sensor body according to claim 1, wherein the sensor body comprises a pair of electrodes erected on the surface of the substrate at a predetermined interval, and a polymer film disposed at least between the pair of electrodes. Capacitive sensor.