JP2006084231A - Capacity type humidity sensor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacity type humidity sensor capable of preventing the lowering of response, and its manufacturing method. <P>SOLUTION: The capacity type humidity sensor 300 is equipped with a detection substrate 100 provided with a detection part (electrodes 131 and 132 and a humidity-sensitive film 150) changed in its capacity by humidity and a circuit board 200 provided with a circuit part 230 for subjecting the capacity change of the detection part to electric signal processing and constituted by electrically connecting the electrodes 131 and 132 and the circuit part 230. A sensor pad 162 as the connection terminal to the circuit part 230 is provided on the back of the detection part forming surface of the detection substrate 100, and the sensor pad 162 and the electrodes 131 and 132 are electrically connected through the conductor 161 in a through-hole 160. Accordingly, since a protective material 330 such as a gel or the like may not provided on the detection part as is conventionally, the lowering of response can be prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is provided with a detection board provided with a detection unit whose capacity changes depending on humidity on one side, and a circuit board provided with a circuit unit for processing an electric signal of the capacitance change of the detection unit, The present invention relates to a capacitive humidity sensor that is electrically connected to a circuit unit and a method for manufacturing the same.

  Conventionally, the present applicant has previously disclosed Patent Document 1 as an example of a capacitive humidity sensor in which a moisture-sensitive film whose relative dielectric constant changes according to humidity is interposed between a pair of electrodes.

  The capacitive humidity sensor shown in Patent Document 1 is formed on a semiconductor substrate so that a pair of electrodes are formed on the same plane of the semiconductor substrate so as to face each other with a distance therebetween, and the pair of electrodes and the pair of electrodes are covered. It is formed by forming a moisture sensitive film whose relative dielectric constant changes according to humidity. In addition, an insulating film (second insulating film) is provided between the electrode and the moisture sensitive film, thereby ensuring the moisture resistance of the electrode. Therefore, an electrode can be formed using a material that can be used in a normal semiconductor production line, such as aluminum (Al), for example, without using an expensive metal that is particularly excellent in moisture resistance such as a noble metal. .

Further, a circuit portion (circuit element portion) that performs signal processing of capacitance change between the electrodes is provided on the electrode formation surface side of the semiconductor substrate. If the wiring material used for this circuit part is the same as the constituent material of the electrodes, the manufacturing process can be simplified.
JP 2002-243690 A

  By the way, in the capacitive humidity sensor having the above configuration, in order to protect (prevent corrosion) at least a pad as an external connection terminal provided at the end of the circuit portion, the surface thereof is covered with a protective material such as gel. There is a need.

  However, the electrode and the circuit portion are integrated on the same surface side of the semiconductor substrate. Moreover, it is difficult to apply the gel locally. Accordingly, the entire surface of the semiconductor substrate on which the circuit part is formed is covered with gel, and the detection part made of the electrode and the moisture sensitive film is also covered with gel, so that the responsiveness of the capacitive humidity sensor is deteriorated.

  In addition to the above configuration, a detection board having a detection unit whose capacity changes depending on humidity and a circuit board having a circuit unit are separately prepared and electrically connected to electrodes via bonding wires or the like. A capacitive humidity sensor having a structure in which a sensor pad and a circuit unit are electrically connected is also known. However, also in this case, since it is necessary to cover the sensor pad of the detection substrate, the moisture sensitive film and the electrode are covered with the gel, and the responsiveness of the capacitive humidity sensor deteriorates.

  In view of the above problems, an object of the present invention is to provide a capacitive humidity sensor that can prevent a decrease in responsiveness and a method for manufacturing the same.

  In order to achieve the above object, the invention according to any one of claims 1 to 6 carries out an electrical signal processing of a detection board provided with a detection unit whose capacitance changes depending on humidity on one side, and a capacitance change of the detection unit. The present invention relates to a capacitive humidity sensor including a circuit board provided with a circuit unit and electrically connecting the detection unit and the circuit unit.

  First, as described in claim 1, a sensor pad as a connection terminal for the circuit unit is provided on the back surface of the detection unit forming surface of the detection substrate, and the sensor pad and the detection unit are provided on the detection substrate. It is electrically connected through a conductor in the through hole.

  Thus, according to the present invention, the detection unit and the circuit unit are provided on different substrates, and the sensor pad is provided on the back surface of the detection unit forming surface in the detection substrate. Therefore, unlike the prior art, it is not necessary to provide a protective material such as a gel on the detection unit, so that a reduction in responsiveness can be prevented.

  According to a second aspect of the present invention, the circuit board is provided with a first pad electrically connected to the circuit unit as a connection terminal to the sensor pad, and the sensor pad forming surface of the detection board and the circuit board In a state where the detection board and the circuit board are laminated so that the first pad formation surface faces each other, the sensor pad and the first pad are electrically connected via the connection material, and the detection board It is preferable that the sensor pad forming surface and the first pad forming surface of the circuit board are hermetically sealed with a sealing material provided in an annular shape.

  With such a configuration, corrosion of the connection portion (sensor pad, first pad, and connection material) between the electrode and the circuit portion can be prevented, and the size of the sensor in the planar direction can be reduced.

  According to a third aspect of the present invention, when the circuit portion is provided on the first pad forming surface side of the circuit board and hermetically sealed together with the first pad by the sealant, the circuit portion is protected. Even if it is necessary, corrosion of the circuit part can be prevented without separately providing a protective material on the circuit part, which is preferable. However, as described in claim 4, the circuit portion may be provided on the back surface side of the first pad forming surface of the circuit board, and the surface thereof may be covered and protected by a protective material.

  Specifically, as described in claim 5, a second pad electrically connected via a circuit portion and a wiring portion is provided on a portion of the circuit board that does not overlap with the detection substrate in a stacked state. A configuration is good. In this case, even if the connection portion (the sensor pad, the first pad, and the connection material) between the electrode and the circuit portion is hermetically sealed with the surfaces of both substrates and the sealing material, the second pad For example, a characteristic test can be performed by bringing a tester into contact with the external device, or an external connection can be made through the second pad. Further, since the second pad is also provided on a surface different from the electrode formation surface, it is possible to prevent a decrease in responsiveness.

  According to a sixth aspect of the present invention, the detection unit includes a pair of electrodes disposed on the same plane on the semiconductor substrate so as to face each other with the comb teeth meshing with each other, the pair of electrodes, and the pair of electrodes It is preferable to be constituted by a moisture sensitive film provided so as to cover between the electrodes.

  With such a configuration, since the facing area can be increased, the amount of change in capacitance between the electrodes can be increased. Further, an insulating substrate such as a glass substrate can be used as the substrate, but a semiconductor process can be used by using a semiconductor substrate. Therefore, the manufacturing cost can be reduced. In practice, an insulating film is provided between the semiconductor substrate and the electrode and between the electrode and the moisture sensitive film.

  The invention described in claims 7 to 9 relates to a manufacturing method for realizing the configuration of the invention described in claims 1 to 3, and the function and effect thereof are the functions of the invention described in claims 1 to 3. Since it is the same as the effect, the description is omitted.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
1A and 1B are diagrams illustrating a schematic configuration of a capacitive humidity sensor according to the present embodiment, in which FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along a line AA in FIG. In FIG. 1A, for the sake of convenience, a pair of electrodes under the moisture-sensitive film and the second insulating film are shown in a transparent manner.

  As shown in FIGS. 1 (a) and 1 (b), a capacitive humidity sensor 300 has a detection substrate 100 provided with a detection unit whose capacitance changes depending on humidity on one side, and the capacitance change of the detection unit. The circuit board 200 is provided with a circuit unit for signal processing.

  First, the detection substrate 100 will be described. Reference numeral 110 denotes a semiconductor substrate as a substrate, which is formed of silicon in this embodiment. A pair of electrodes 131 and 132 are formed on the upper surface of the semiconductor substrate 110 with a silicon oxide film 120 as an insulating film interposed therebetween. The electrodes 131 and 132 are spaced apart from each other on the same plane on the silicon oxide film 120.

  Although the shape of the electrodes 131 and 132 is not particularly limited, in the present embodiment, as shown in FIG. 1A, each of the electrodes 131 and 132 includes the common electrode portions 131a and 132a. A plurality of (three in FIG. 1) comb electrode portions 131b and 132b extending in one direction from the common electrode portions 131a and 132a. And a pair of electrodes 131 and 132 are arrange | positioned so that each comb-tooth electrode part 131b and 132b of a pair of electrodes 131 and 132 may be arranged alternately. As described above, by adopting the comb-teeth shape as the pair of electrodes 131 and 132, the area where the comb-teeth electrode portions 131b and 132b face each other is increased while the arrangement area of the electrodes 131 and 132 is reduced. Can do. As a result, the amount of change in capacitance between the electrodes 131 and 132 that changes with changes in the surrounding humidity increases, and the sensitivity of the capacitive humidity sensor 300 is improved.

  As the electrodes 131 and 132, for example, wiring materials such as Al, Ag, Au, Cu, Ti, and Poly-Si can be applied. However, since noble metals (such as Au) that are corrosion resistant to moisture are expensive and become sources of contamination in the semiconductor process, they are formed using Al that is inexpensive and can be manufactured in the semiconductor process in this embodiment. Has been.

  Therefore, in this embodiment, the silicon nitride film 140 as a protective film is formed on the semiconductor substrate 110 so as to cover the pair of electrodes 131 and 132. Thereby, the corrosion by the water | moisture content of the electrodes 131 and 132 is suppressed.

  A moisture sensitive film 150 made of a hygroscopic polymer material is formed on the silicon nitride film 140 so as to cover the pair of electrodes 131 and 132 and the electrodes 131 and 132. As the polymer material, polyimide, cellulose acetate butyrate, or the like can be applied. In the present embodiment, polyimide is used. The pair of electrodes 131 and 132 and the moisture sensitive film 150 constitute a detection unit. In FIG. 1A, a rectangular region surrounded by a broken line indicates a region where the moisture sensitive film 150 is formed.

  As shown in FIG. 1A, electrode pads 131c and 132c are formed at the ends of the electrodes 131 and 132, respectively. Through holes 160 are formed in the semiconductor substrate 110 and the silicon oxide film 120 with the electrode pads 131c and 132c as bottoms, and the electrode pads 131c and 132c are connected to the semiconductor through the conductors 161 disposed in the through holes 160. It is formed on the back surface of the substrate 110 on which the electrodes 131 and 132 are formed, and is electrically connected to a sensor pad 162 as a connection terminal connected to the circuit portion of the circuit board 200. The sensor pad 162 is exposed for connection with the circuit portion of the circuit board 200. The constituent material of the conductor 161 is not particularly limited as long as it can be disposed in the through hole 160, but in the present embodiment, like the electrodes 131 and 132, it is formed using Al. Reference numeral 163 denotes an insulating layer.

  Next, the circuit board 200 will be described. In FIG. 1B, reference numeral 210 denotes a semiconductor substrate as a substrate, which is formed of silicon in this embodiment. A circuit unit 230 (including, for example, a CV conversion circuit that converts voltage) is formed on the surface of the semiconductor substrate 210 to process a capacitance change between the electrodes 131 and 132. The circuit unit 230 is constituted by, for example, a CMOS transistor. In the present embodiment, for convenience, the circuit unit 230 is made of Al formed on the semiconductor substrate 210 via the silicon oxide film 220 as an insulating film. Only the wiring part is shown.

  On the silicon oxide film 220, a first pad 231 is electrically connected to the circuit unit 230 via a wiring unit (not shown) and serves as a connection terminal connected to the sensor pad 162 of the detection substrate 100. Is formed. Further, in order to take out the signal processed by the circuit unit 230 to the outside in the laminated state described later and in an area that does not overlap the detection substrate 100, the wiring unit (see FIG. A second pad 232 is formed as an external connection terminal that is electrically connected to the circuit unit 230 via a not-shown). In the present embodiment, the first pad 231 and the second pad 232 are also formed using Al like the electrodes 131 and 132.

  Reference numeral 240 denotes a silicon nitride film as a protective film for preventing corrosion of the circuit unit 230, and the first pad 231 and the second pad 232 are exposed to the silicon nitride film 240.

  The detection substrate 100 and the circuit substrate 200 configured as described above are stacked so that the sensor pad formation surface of the detection substrate 100 faces the first pad formation surface of the circuit substrate 200, and in this stacked state, The sensor pad 162 of the detection board 100 and the first pad 231 of the circuit board 200 are connected via a connection material 310 (for example, solder). That is, the electrode pads 131 and 132 and the circuit unit 230 are electrically connected by connecting the sensor pad 162 and the first pad 231 on the back side of the surface on which the electrodes 131 and 132 are formed.

  Further, a sealing material 320 is annularly arranged between the sensor pad forming surface of the detection substrate 100 and the first pad forming surface of the circuit substrate 100, whereby the sensor pad 162, the first pad 231, The connection part and the circuit part 230 are hermetically sealed. The sealing material 320 includes a sensor pad forming surface and a first pad forming surface in a state where the sensor pad forming surface is disposed between the sensor pad forming surface of the detection substrate 100 and the first pad forming surface of the circuit board 100. Any material that can hermetically seal the connection portion between the pad 162 and the first pad 231 and the circuit portion 230 can be used. In the present embodiment, an epoxy-based adhesive is applied, which is hermetically sealed and the detection substrate 100 and the circuit substrate 200 are fixed. Therefore, the connection reliability between the sensor pad 162 (electrodes 131 and 132) and the first pad 231 (circuit unit 230) can be improved.

  Furthermore, the second pad 232 formed on the outer peripheral side with respect to the arrangement position of the sealing material 320 is protected by the protective material 330. This protective material 330 is for preventing the corrosion of the second pad 232, and silicon gel is applied in the present embodiment. The second pad 232 is connected to the outside via a bonding wire or the like, but is omitted for convenience in this embodiment.

  In the capacitive humidity sensor 300 configured as described above, when moisture permeates into the moisture sensitive film 150, the moisture has a large relative dielectric constant. Therefore, the relative dielectric constant of the moisture sensitive film 150 is determined according to the amount of the penetrated moisture. Changes. As a result, the capacitance of the capacitor constituted by the pair of electrodes 131 and 132 changes with the moisture sensitive film 150 as a part of the dielectric, and the capacitance change is processed by the circuit unit 230 and converted into a voltage. Since the amount of moisture contained in the moisture sensitive film 150 corresponds to the humidity around the capacitive humidity sensor 300, the humidity can be detected from the capacitance between the pair of electrodes 131 and 132.

  Next, a manufacturing method of the capacitive humidity sensor 300 having the above configuration will be described with reference to FIGS. FIGS. 2A and 2B are cross-sectional views for each process showing an example of a method of manufacturing the capacitive humidity sensor 300, where FIG. 2A shows a detection board preparation process, FIG. 2B shows a circuit board preparation process, and FIG. 2C shows a connection process. Yes.

  First, a detection substrate preparation process is performed. As shown in FIG. 2A, a silicon oxide film 120 which is an insulating film is formed on the surface of the semiconductor substrate 110 by, for example, a CVD method, and Al is deposited on the silicon oxide film 120 by using, for example, a vapor deposition method. The electrodes 131 and 132 are formed by patterning. After the electrodes 131 and 132 are formed, a silicon nitride film 140 that is a protective film is formed by, for example, a plasma CVD method so as to cover the electrodes 131 and 132 and between the electrodes 131 and 132, and the electrodes 131 and 132 and the electrodes 131 and 132 are formed. A moisture sensitive film 150 is formed in a predetermined region on the silicon nitride film 140 so as to cover the space.

  Here, as a method of forming the moisture sensitive film 150, a spin coating method or a screen printing method can be applied. In this embodiment, a polyimide precursor (a moisture sensitive film precursor having a polyamic acid as a basic skeleton) is used. The moisture-sensitive film 150 made of polyimide is screen-printed using a paste made of a body, deposited on the silicon nitride film 140 which is the outermost surface of the semiconductor substrate 110, and then heat-cured (imidized) at a predetermined temperature. Formed.

  Furthermore, in the present embodiment, a sensor pad 162 that serves as a connection terminal with the circuit board 200 is formed on the back surface of the electrode formation surface of the semiconductor substrate 10. Specifically, a mask (not shown) is formed on the back surface of the semiconductor substrate 110, and the semiconductor substrate 110 is etched with an etchant such as a TMAH (tetramethylammonium hydroxide) solution. After the etching, the silicon oxide film 120 on the etched semiconductor substrate region is removed, and a through hole 160 with the sensor pad 162 as a bottom is formed.

  And after forming the insulating layer 163 on the back surface of the electrode formation surface of the semiconductor substrate 110 and the side surface of the through hole 160, for example, Al is deposited from the back surface side of the semiconductor substrate 110 and patterned. As a result, the conductor 161 is formed in the through hole 160, and the sensor pad 162 connected to the conductor 161 is formed on the back surface of the electrode formation surface of the semiconductor substrate 110. The formation method of the through hole 160, the conductor 161, and the sensor pad 162 is not limited to the above example. For example, screen printing or inkjet printing may be applied to the formation of the conductor 161. It is preferable to arrange many metals in the through hole 160.

  Next, a circuit board preparation step is performed. A part of the circuit unit 230 is formed on the surface of the semiconductor substrate 210 by ion implantation, thermal diffusion, CVD, or the like. Subsequently, a silicon oxide film 220 which is an insulating film is formed by, for example, a CVD method, a contact hole (not shown) is formed, and then Al is deposited on the silicon oxide film 220 by, for example, an evaporation method. Then, by patterning, the circuit portion 230, the first pad 231, the second pad 232, and a wiring portion (not shown) for connecting the circuit portion 230 to the first pad 231 and the second pad 232 are provided. Form.

  Furthermore, in this embodiment, a silicon nitride film 240 that is a protective film is formed thereon by, for example, a plasma CVD method. At that time, the silicon nitride film 240 on the first pad 231 and the second pad 232 is removed by etching in order to electrically connect the circuit board 200 and the detection board 100 and the other outside. It should be noted that either the detection board preparation step and the circuit board preparation step may be performed earlier or in parallel.

  And a connection process is implemented in the state which prepared the detection board | substrate 100 and the circuit board 200. FIG. A connection material 310 (solder in this embodiment) is applied on the first pad 231 of the circuit board 200, and the detection board 100 is positioned so that the sensor pad 162 is opposed to the first pad 231. In this state, for example, a heat tool (not shown) is brought into contact with the electrode formation surface of the detection substrate 100 and heated while being pressed in the direction of the circuit substrate 200. Thereby, the connection material 310 is melted and joined to the sensor pad 162 and the first pad 231, and the electrodes 131 and 132 and the circuit unit 230 are electrically connected.

  After the connection between the sensor pad 162 and the first pad 231, an epoxy-based adhesive as the sealing material 320 is placed in the gap between the sensor pad forming surface of the detection substrate 100 and the first pad forming surface of the circuit substrate 100. Inject in a ring and heat to cure. Thereby, the connection part between the sensor pad 162 and the first pad 231 and the circuit part 230 are hermetically sealed by the sensor pad forming surface of the detection substrate 100, the first pad forming surface of the circuit substrate 100, and the sealing material 320. Sealed. Thus, the capacitive humidity sensor 300 is formed.

  The second pad 232 is an external connection terminal for taking out a signal processed by the circuit unit 230 to the outside. Therefore, for example, after the characteristic inspection of the capacitive humidity sensor 300 is completed, a bonding wire (not shown) In order to prevent corrosion, the second pad 232 (and its connecting portion) is covered and protected by a protective material 330 such as silicon gel. Also in this embodiment, the second pad 232 is connected to the outside via a bonding wire, but is omitted for convenience.

  As described above, according to the configuration of the capacitive humidity sensor 300 in the present embodiment, the detection unit including the electrodes 31 and 32 and the moisture sensitive film 50 and the circuit unit 230 are provided on different substrates 100 and 200. A sensor pad 162 as a connection terminal with the circuit unit 230 is provided on the back surface of the detection unit forming surface. Therefore, unlike the prior art, it is not necessary to provide a protective material such as a gel on the detection unit, so that a reduction in responsiveness can be prevented.

  In the present embodiment, the sensor pad is stacked with the detection substrate 100 and the circuit board 200 so that the sensor pad formation surface of the detection substrate 100 and the first pad formation surface of the circuit board 200 face each other. 162 and the first pad 231 are connected to each other through a connection material 310, and the connection portion is hermetically sealed against the outside air by the sensor pad formation surface, the first pad formation surface, and the sealing material 320. Has been. Therefore, corrosion of the connection portion between the sensor pad 162 and the first pad can be prevented, and the size of the sensor 300 in the planar direction can be reduced. That is, if the size in the plane direction is the same, the area of the detection unit can be increased as compared with the conventional case, so that the sensitivity can be improved.

  In the present embodiment, the circuit unit 230 and the first pad 231 are formed on the same surface side of the semiconductor substrate 210, and the circuit unit 230 together with the first pad has the sensor pad formation surface, the first pad. The pad forming surface and the sealing material 320 are hermetically sealed against the outside air. Accordingly, corrosion of the circuit portion can be prevented without providing the silicon nitride film 240 as a protective film on the circuit portion 230 (silicon oxide film 210). In the present embodiment, the silicon nitride film 240 is provided in order to prevent the circuit unit 230 from being affected by the outside air between the formation of the circuit board 200 and the connection process.

  Further, in the present embodiment, the second pad 232 for taking out the signal processed by the circuit unit 230 to the outside is located on the first pad forming surface of the circuit board 200 from the position where the sealing material 320 is disposed. Is also formed on the outer peripheral side. Therefore, even in a state where the connection portion between the sensor pad 162 and the first pad 231 is hermetically sealed with the sealing material 320 first, the characteristic inspection is performed by contacting the second pad 232 with, for example, a tester. It can also be implemented or electrically connected to the outside via the second pad 232. Further, since the second pad 232 is also provided on a surface different from the electrode formation surface, the second pad 232 is covered and protected by the protective material 330 without covering the electrodes 131 and 132 and the moisture sensitive film 150. can do.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made.

  In the present embodiment, the semiconductor substrate 110 made of silicon is used as the substrate constituting the detection substrate 100, and the electrodes 131 and 132 are formed on the semiconductor substrate 110 via the silicon oxide film 120. When the semiconductor substrate 110 is used as the substrate as described above, the detection substrate 100 can be formed by a general semiconductor process, and thus the manufacturing cost can be reduced. However, an insulating substrate such as a glass substrate can also be applied as the substrate.

  Similarly, an example in which the semiconductor substrate 210 is employed as a substrate constituting the circuit substrate 200 and the circuit substrate 200 is formed by utilizing a semiconductor process has been shown. However, the circuit board 200 is not limited to the above example, and ceramic, resin, or the like can be applied as the board.

  In this embodiment, the circuit unit 230 is also hermetically sealed by the sensor pad forming surface of the detection substrate 100, the first pad forming surface of the circuit substrate 200, and the sealing material 320. . That is, the example in which the circuit portion 230 and the first pad 231 are formed on the same surface side of the semiconductor substrate 210 is shown. However, as shown in FIG. 3, the circuit unit 230 may be provided on the back side of the first pad forming surface. FIG. 3 is a schematic sectional view showing a modification of the present embodiment, and corresponds to FIG.

  In such a configuration, the circuit portion 230 may be covered with a protective material 330 such as silicon gel. In FIG. 3, reference numeral 250 denotes a through hole provided in the semiconductor substrate 210, reference numeral 251 denotes a conductor in the through hole 250, reference numeral 252 denotes an insulating layer, and the circuit unit 230 is an end portion of the circuit unit 230. The pad 230a is connected to the conductor 251. The second pad 232 is provided on the surface where the circuit unit 230 is formed, and is covered and protected by a protective material 330. However, the configuration shown in FIGS. 1A and 1B does not need to provide the protective material 330 on the back surface side of the first pad forming surface, so that the size of the sensor 300 in the stacking direction can be reduced. Can do.

  The configuration in which the detection substrate 100 and the circuit substrate 200 are stacked is not limited to the above configuration. In addition, for example, only the second pad 232 may be formed on the back side of the first pad forming surface.

  In order to electrically connect the electrodes 131 and 132 and the circuit unit 230, the detection substrate 100 and the circuit substrate 200 are not necessarily stacked. For example, the sensor pad 161 provided on the back surface of the electrode formation surface and the first pad 231 may be connected by a bonding wire. If at least the electrode forming surface side of the detection substrate 100 does not have a connection terminal that connects to the outside, the protective material 330 is not disposed on the detection unit including the electrodes 131 and 132 and the moisture sensitive film 150. Accordingly, it is possible to prevent a decrease in responsiveness.

  Further, in the present embodiment, an example in which the pair of electrodes 131 and 132 are provided in a comb shape is shown. However, the structure of the detection unit is not particularly limited as long as the moisture sensitive film 150 is interposed between the pair of electrodes 131 and 132.

It is a figure which shows schematic structure of the capacitive humidity sensor of this invention, (a) is a top view, (b) is sectional drawing in the AA cross section of (a). It is sectional drawing according to process which shows an example of the manufacturing method of a capacitive humidity sensor, (a) is a detection board preparation process, (b) is a circuit board preparation process, (c) has shown the connection process. It is sectional drawing which shows a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Detection substrate 110 ... Semiconductor substrate 120 ... Silicon oxide film 131,132 ... Electrode 140 ... Silicon nitride film 160 ... Through hole 161 ... Conductor 162 ... Sensor Pad 200 ... Circuit board 210 ... Semiconductor substrate 230 ... Circuit part 231 ... First pad 232 ... Second pad 300 ... Capacitive humidity sensor 310 ... Connection material 320 ... Sealant 330 ... Protective material

Claims (9)

On the one side, a detection board provided with a detection unit whose capacity changes depending on humidity,
A circuit board provided with a circuit unit for processing an electric signal for capacitance change of the detection unit,
A capacitive humidity sensor formed by electrically connecting the detection unit and the circuit unit,
A sensor pad as a connection terminal for the circuit unit is provided on the back surface of the detection unit forming surface of the detection substrate.
The capacitive humidity sensor, wherein the sensor pad and the detection unit are electrically connected via a conductor in a through hole provided in the detection substrate. The circuit board is provided with a first pad electrically connected to the circuit portion as a connection terminal to the sensor pad,
In the state where the detection substrate and the circuit board are stacked such that the sensor pad formation surface of the detection substrate and the first pad formation surface of the circuit substrate face each other, the sensor pad and the first pad Are hermetically sealed by a sealing material provided in an annular shape between the sensor pad forming surface of the detection substrate and the first pad forming surface of the circuit substrate while being electrically connected via a connecting material. The capacitive humidity sensor according to claim 1, wherein the capacitive humidity sensor is provided.   The said circuit part is provided in the 1st pad formation surface side of the said circuit board, and is airtightly sealed with the said sealing material with the said 1st pad. Capacitive humidity sensor.   3. The capacitive humidity sensor according to claim 2, wherein the circuit unit is provided on a back surface side of the first pad forming surface of the circuit board, and the surface thereof is covered and protected by a protective material.   3. The circuit board is provided with a second pad that is electrically connected to the circuit portion via a wiring portion at a portion that does not overlap the detection substrate in a stacked state. The capacitive humidity sensor according to any one of -4.   The detection unit is provided on the same plane on the semiconductor substrate so as to cover a pair of electrodes arranged so as to face each other with the comb teeth meshing with each other and between the pair of electrodes and the pair of electrodes. The capacitive humidity sensor according to any one of claims 1 to 5, wherein the humidity sensor is configured by a moisture sensitive film. A detection board preparation step of preparing a detection board provided with a detection unit whose capacity changes with humidity on one side;
A circuit board preparation step of preparing a circuit board provided with a circuit unit for processing an electric signal for capacitance change of the detection unit;
A method of manufacturing a capacitive humidity sensor comprising a connection step of electrically connecting the detection unit and the circuit unit,
In the detection substrate preparation step, a sensor pad as a connection terminal for the circuit unit is formed on the back surface of the detection unit formation surface of the detection substrate, electrically connected to the detection unit via a conductor in a through hole. A method for manufacturing a capacitive humidity sensor. In the circuit board preparation step, as a connection terminal with the sensor pad, a first pad electrically connected to the circuit unit is formed,
In the connecting step, the sensor pad and the first pad are electrically connected via a connecting material, and the sensor pad forming surface of the detection substrate and the first pad forming surface of the circuit substrate are opposed to each other. A capacitive humidity sensor according to claim 7, wherein a sealing material is annularly arranged at a peripheral portion between the sensor pad and the connection portion between the sensor pad and the first pad to be hermetically sealed. Manufacturing method. In the circuit board preparation step, the circuit portion is formed on the first pad forming surface side of the circuit board,
9. The method of manufacturing a capacitive humidity sensor according to claim 8, wherein, in the connecting step, the circuit portion is hermetically sealed with the sealing material together with the first pad.

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