JP6218270B2 - Gas sensor - Google Patents

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JP6218270B2
JP6218270B2 JP2013109665A JP2013109665A JP6218270B2 JP 6218270 B2 JP6218270 B2 JP 6218270B2 JP 2013109665 A JP2013109665 A JP 2013109665A JP 2013109665 A JP2013109665 A JP 2013109665A JP 6218270 B2 JP6218270 B2 JP 6218270B2
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井澤　邦之
邦之 井澤
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この発明はガスセンサに関する。 This invention relates to the gas sensor.

金属酸化物半導体ガスセンサの抵抗値は周囲の雰囲気の絶対湿度の影響を受けるので、サーミスタ等により周囲の気温を測定し、ガスセンサの出力を補正することが行われている。またガスセンサでは、フィルタにより不要なガスを吸着あるいは酸化して除去することが行われている。そしてSi等の基板上に金属酸化物半導体とヒータと電極とを設けたMEMS型のガスセンサでは、消費電力を小さくするため、ヒータの駆動時間を制限し、かつ金属酸化物半導体を急激に温度変化させることが行われている。これに伴って、フィルタへの依存が深まり、より多量のフィルタ材料を用い、あるいはガスセンサの通気性を制限し、フィルタがガスを確実に処理できるようにすることが行われている。   Since the resistance value of the metal oxide semiconductor gas sensor is affected by the absolute humidity of the surrounding atmosphere, the ambient temperature is measured by a thermistor or the like to correct the output of the gas sensor. In the gas sensor, unnecessary gas is removed by adsorption or oxidation using a filter. In a MEMS type gas sensor with a metal oxide semiconductor, heater, and electrode on a substrate such as Si, the heater drive time is limited and the temperature of the metal oxide semiconductor changes rapidly to reduce power consumption. Has been done. Along with this, the dependence on the filter is deepened, and a larger amount of filter material is used, or the air permeability of the gas sensor is limited so that the filter can reliably process the gas.

関連する先行技術を示す。特許文献１（JP2004-37180A）は、MEMS型のガスセンサでの、金属酸化物半導体を加熱するためのヒータの抵抗値から、絶対湿度を測定することを提案している。即ち周囲の絶対湿度が変化すると、ヒータからの放熱量が変化し、ヒータの抵抗値が変化する。そして絶対湿度の測定用のヒータを、金属酸化物半導体のヒータに共用する。   Related prior art is shown. Patent Document 1 (JP2004-37180A) proposes measuring an absolute humidity from a resistance value of a heater for heating a metal oxide semiconductor in a MEMS type gas sensor. That is, when the ambient absolute humidity changes, the amount of heat released from the heater changes, and the resistance value of the heater changes. A heater for measuring absolute humidity is also used as a metal oxide semiconductor heater.

JP2004-37180AJP2004-37180A

発明者は、フィルタの内側で、MEMS型のセンサチップ（感ガス部とヒータ、電極等を設けた基板）の周囲での湿度は、ガスセンサの外部の湿度と異なることを見出した。図６に示すように、ガスセンサの外部の温度と相対湿度とを急変させると、センサチップの周囲の温度は速やかに追随するが、センサチップの周囲の湿度は追随が遅い。これはフィルタが水蒸気を吸収／放出し、フィルタよりもセンサチップ側では、外部の湿度変動に対する応答が遅れるためである。従ってガスセンサの外部の湿度を測定しても、センサの湿度依存性を正確に補正することは難しい。なお特許文献１のガスセンサでは、フィルタがないため、このような課題は生じない。   The inventor has found that the humidity around the MEMS type sensor chip (the substrate provided with the gas sensitive part, the heater, and the electrode) inside the filter is different from the humidity outside the gas sensor. As shown in FIG. 6, when the temperature outside the gas sensor and the relative humidity are suddenly changed, the temperature around the sensor chip quickly follows, but the humidity around the sensor chip follows slowly. This is because the filter absorbs / releases water vapor, and the sensor chip side of the filter is delayed in response to external humidity fluctuations. Therefore, even if the humidity outside the gas sensor is measured, it is difficult to accurately correct the humidity dependency of the sensor. Note that the gas sensor of Patent Document 1 does not have such a problem because there is no filter.

この発明は、フィルタの影響を受けずに、センサチップの周囲の湿度を測定できるようにすることを課題とする。
この発明の追加の課題は、湿度センサをガスセンサに容易に一体化することにある。
この発明の他の課題は、金属酸化物半導体での可燃性ガスの燃焼熱等の影響を受けずに、湿度を正確に測定することにある。 An object of the present invention is to be able to measure the humidity around the sensor chip without being affected by the filter.
An additional object of the present invention is to easily integrate the humidity sensor into the gas sensor.
Another object of the present invention is to accurately measure humidity without being affected by the combustion heat of a combustible gas in a metal oxide semiconductor.

この発明は、半導体基板のキャビテイ上に設けられた支持膜に、金属酸化物半導体膜もしくは酸化触媒膜と、ヒータとを設けたセンサチップと、
不要なガスを除去するフィルタと、
前記センサチップとフィルタとを間隔をおいてハウジングに収容し、フィルタを通過した雰囲気をセンサチップへ拡散させるガスセンサにおいて、
前記半導体基板上でかつ前記キャビテイとは異なる位置に、センサチップの周囲の相対湿度を測定する高分子感湿膜が設けられていることを特徴とする。 The present invention provides a sensor chip in which a metal oxide semiconductor film or an oxidation catalyst film and a heater are provided on a support film provided on the cavity of a semiconductor substrate,
A filter that removes unwanted gas,
In the gas sensor that accommodates the sensor chip and the filter in a housing at an interval and diffuses the atmosphere that has passed through the filter to the sensor chip,
A polymer moisture sensitive film for measuring the relative humidity around the sensor chip is provided on the semiconductor substrate at a position different from the cavity .

好ましくは、支持膜に、金属酸化物半導体膜と、ヒータと、金属酸化物半導体膜に接続された一対の電極、とが設けられ、Preferably, the support film is provided with a metal oxide semiconductor film, a heater, and a pair of electrodes connected to the metal oxide semiconductor film,
半導体基板上にはさらに、高分子感湿膜に接続された一対の電極、及び４個のパッドが設けられ、  On the semiconductor substrate, a pair of electrodes connected to the polymer moisture-sensitive film and four pads are further provided.
ヒータの一端と、金属酸化物半導体膜に接続された一対の電極の一方と、高分子感湿膜に接続された一対の電極の一方とが、第１のパッドに接続され、  One end of the heater, one of the pair of electrodes connected to the metal oxide semiconductor film, and one of the pair of electrodes connected to the polymer moisture sensitive film are connected to the first pad,
ヒータの他端が第２のパッドに接続され、金属酸化物半導体膜に接続された他方の電極が第３のパッドに接続され、高分子感湿膜に接続された他方の電極が第４のパッドに接続されている。  The other end of the heater is connected to the second pad, the other electrode connected to the metal oxide semiconductor film is connected to the third pad, and the other electrode connected to the polymer moisture sensitive film is the fourth pad. Connected to the pad.

この発明では、センサチップの周囲の湿度を測定する。従ってフィルタのためセンサチップの周囲と外部とで湿度が異なっても、金属酸化物半導体膜あるいは酸化触媒膜が置かれている雰囲気の湿度を測定できる。
センサチップは、半導体基板のキャビテイ上の支持膜に、金属酸化物半導体膜もしくは酸化触媒膜と、ヒータとを設けたものなので、支持膜とは別体にかつ容易に高分子感湿膜を設けることができる。さらに感湿部は、金属酸化物半導体膜での可燃性ガスの燃焼熱等の影響を受けない。 In the present invention, the humidity around the sensor chip is measured. Therefore, the humidity of the atmosphere in which the metal oxide semiconductor film or the oxidation catalyst film is placed can be measured even if the humidity differs between the periphery and the outside of the sensor chip due to the filter.
Since the sensor chip is provided with a metal oxide semiconductor film or oxidation catalyst film and a heater on the support film on the cavity of the semiconductor substrate, a polymer moisture sensitive film is easily provided separately from the support film. be able to. Furthermore, the moisture sensitive part is not affected by the combustion heat of the combustible gas in the metal oxide semiconductor film.

ハウジングは例えばベースとカバーとから成るが、カバーにセンサチップを直接取り付け、ベースを省略しても良い。   The housing includes a base and a cover, for example, but the sensor chip may be directly attached to the cover and the base may be omitted.

実施例でのセンサチップの平面図Plan view of sensor chip in the embodiment 実施例のセンサチップの平面図Plan view of the sensor chip of the embodiment 実施例のガスセンサの断面図Sectional view of the gas sensor of the embodiment 実施例のガス検出装置の回路図Circuit diagram of the gas detector of the embodiment 実施例のガス検出装置の動作タイミングを示す図The figure which shows the operation | movement timing of the gas detection apparatus of an Example. ガスセンサ内部の相対湿度と温度の測定例を示す図Figure showing a measurement example of relative humidity and temperature inside the gas sensor

以下に本発明を実施するための最適実施例を示す。   In the following, an optimum embodiment for carrying out the present invention will be shown.

図１〜図６に実施例を示す。図１はセンサチップ２を示し、４はSi等から成る半導体基板、６はキャビテイで、図１の表面側から開けたものでも、裏面側から開けたものでも良い。８は支持膜で、金属酸化物半導体膜９あるいはPt等の貴金属触媒を担持するアルミナ等の担体と、電極及びヒータを支持する。支持膜８はSiO2，Ta2O5等の膜で、１層あるいは複数層から成る。金属酸化物半導体膜９は例えばSnO2膜で、金属酸化物半導体の種類は任意であり、貴金属等が担持されていても良く、薄膜でも厚膜でも良い。支持膜８は例えば４本の脚１０〜１３により支持され、脚１０〜１３には電極及びヒータをパッド２０〜２３と接続する配線が支持されている。図２に、金属酸化物半導体膜９の電極２５，２６とヒータ２４のパターンを示し、ヒータ２４を電極２５，２６の一方に兼用しても良い。 1 to 6 show an embodiment. FIG. 1 shows a sensor chip 2, 4 is a semiconductor substrate made of Si or the like, and 6 is a cavity, which may be opened from the front side or the back side in FIG. Reference numeral 8 denotes a support film, which supports a metal oxide semiconductor film 9 or a carrier such as alumina supporting a noble metal catalyst such as Pt, an electrode and a heater. The support film 8 is a film of SiO 2 , Ta 2 O 5 or the like, and is composed of one layer or a plurality of layers. The metal oxide semiconductor film 9 is, for example, a SnO 2 film, and the type of the metal oxide semiconductor is arbitrary, and may support a noble metal or the like, and may be a thin film or a thick film. The support film 8 is supported by, for example, four legs 10 to 13, and the legs 10 to 13 support wirings for connecting electrodes and heaters to the pads 20 to 23. FIG. 2 shows a pattern of the electrodes 25 and 26 of the metal oxide semiconductor film 9 and the heater 24, and the heater 24 may be used as one of the electrodes 25 and 26.

基板４上で支持膜８とは別体に、感湿性高分子膜から成る感湿膜１４が設けられ、一対の電極１５，１６が感湿膜１４の抵抗値を測定するように配置されている。このようにするとセンサチップ２の周囲の雰囲気の相対湿度を測定できる。なお感湿膜１４を設けている部分に別のキャビテイを設け、キャビテイ上に設けた図示しない支持膜にPtヒータ等を設けても良い。Ptヒータの温度は周囲の雰囲気の熱伝導率で変化し、絶対湿度は雰囲気の熱伝導率を変化させるので、センサチップ２の周囲の雰囲気の絶対湿度を測定できる。実施例では、電極１６をパッド２３に、電極１５を支持膜８と共用のパッド２０に接続したが、電極１５，１６に専用のパッドを設け、センサチップ２当たりのパッドの数を５〜６等としても良い。感湿膜１４は高分子膜に限らず、セラミックス膜でも良い。   A moisture sensitive film 14 made of a moisture sensitive polymer film is provided on the substrate 4 separately from the support film 8, and the pair of electrodes 15 and 16 are arranged to measure the resistance value of the moisture sensitive film 14. Yes. In this way, the relative humidity of the atmosphere around the sensor chip 2 can be measured. Another cavity may be provided in the portion where the moisture sensitive film 14 is provided, and a Pt heater or the like may be provided on a support film (not shown) provided on the cavity. The temperature of the Pt heater changes with the thermal conductivity of the surrounding atmosphere, and the absolute humidity changes the thermal conductivity of the atmosphere. Therefore, the absolute humidity of the ambient atmosphere around the sensor chip 2 can be measured. In the embodiment, the electrode 16 is connected to the pad 23, and the electrode 15 is connected to the pad 20 shared with the support film 8. However, a dedicated pad is provided for the electrodes 15 and 16, and the number of pads per sensor chip 2 is 5-6. And so on. The moisture sensitive film 14 is not limited to a polymer film, and may be a ceramic film.

図３に、ガスセンサ３０の構造を示し、センサチップ２がベース３４にダイボンドされ、例えば４本〜６本のピン３２が図１のパッド２０〜２３等にワイヤボンド等で接続されている。センサチップ２の周囲を覆うように、カバー３６がベース３４に取り付けられ、カバー３４内にフィルタ３８が配置されて、例えば上下一対のメッシュ４０，４２と不織布４４等で、フィルタ３８の材料のこぼれ出しを防止する。   FIG. 3 shows the structure of the gas sensor 30. The sensor chip 2 is die-bonded to the base 34. For example, 4 to 6 pins 32 are connected to the pads 20 to 23 and the like of FIG. A cover 36 is attached to the base 34 so as to cover the periphery of the sensor chip 2, and a filter 38 is disposed in the cover 34. For example, the material of the filter 38 is spilled by a pair of upper and lower meshes 40, 42 and a nonwoven fabric 44. Prevent outage.

フィルタ３８は活性炭、ゼオライト等から成り、不要なガスを吸着あるいは吸収して、センサチップ２に達することを防止する。活性炭、ゼオライト等の吸着材にPt等の触媒を担持させ、不要なガスを触媒で酸化するようにしても良い。   The filter 38 is made of activated carbon, zeolite or the like, and adsorbs or absorbs unnecessary gas to prevent it from reaching the sensor chip 2. A catalyst such as Pt may be supported on an adsorbent such as activated carbon or zeolite, and unnecessary gas may be oxidized with the catalyst.

図４に、ガス検出装置の回路を示す。５０はリチウムイオン電池等の電源、５２はマイクロコンピュータで、ＡＤコンバータ５３と、ガスセンサ３０の駆動部５４，タイマ５５、相対湿度と検出対象ガスの濃度とを検出する検出部５６、及び外部への警報出力を発生する警報部５８とを備えている。６０はトランジスタ等の適宜のスイッチ、６２は周囲温度の測定用のサーミスタあるいは測温抵抗体で、ガスセンサ３０とは別に設けたが、センサチップ２上に設けても良い。またR1〜R3は抵抗である。   FIG. 4 shows a circuit of the gas detection device. Reference numeral 50 denotes a power source such as a lithium ion battery, 52 denotes a microcomputer, an AD converter 53, a drive unit 54 of the gas sensor 30, a timer 55, a detection unit 56 for detecting the relative humidity and the concentration of the detection target gas, and an external connection And an alarm unit 58 that generates an alarm output. 60 is an appropriate switch such as a transistor, and 62 is a thermistor or a resistance thermometer for measuring the ambient temperature, which is provided separately from the gas sensor 30, but may be provided on the sensor chip 2. R1 to R3 are resistors.

図５に、ガスセンサ３０の動作を示す。ガスセンサ３０は例えば30秒周期で動作し、１周期に各１回、例えば0.1秒幅のパルスとより幅の短いパルスとで、ガスセンサ３０に電力を供給し、ヒータ２４をオンすると共に、電極２５，２６間及び電極１５，１６間に電圧を加えて、金属酸化物半導体膜９の抵抗値と、感湿膜１４の抵抗値とを測定する。検出対象ガスは例えばメタン、LPG等の可燃性ガスとCOとで、可燃性ガスもしくはCOのみを検出しても、あるいはエタノール、アンモニア、硫化水素、アセトン等を検出しても良い。ガスセンサ３０内で、フィルタ３８の内側のセンサチップ２の周囲の相対湿度は、図６に示すように、例えば１日程度の時定数で変化する。このため感湿膜１４の抵抗値は１周期毎ではなく、例えば10分に１回、１時間に１回、１日に数回等の頻度で測定しても良い。   FIG. 5 shows the operation of the gas sensor 30. The gas sensor 30 operates in a cycle of, for example, 30 seconds, supplies power to the gas sensor 30 once in each cycle, for example, with a pulse having a width of 0.1 second and a pulse having a shorter width, turns on the heater 24, and the electrode 25. , 26 and between the electrodes 15 and 16, the resistance value of the metal oxide semiconductor film 9 and the resistance value of the moisture sensitive film 14 are measured. The detection target gas is, for example, a flammable gas such as methane or LPG and CO, and only the flammable gas or CO may be detected, or ethanol, ammonia, hydrogen sulfide, acetone, or the like may be detected. In the gas sensor 30, the relative humidity around the sensor chip 2 inside the filter 38 changes with a time constant of about one day, for example, as shown in FIG. For this reason, the resistance value of the moisture sensitive film 14 may be measured at a frequency of, for example, once every 10 minutes, once every hour, several times a day, etc., not every cycle.

金属酸化物半導体膜９の特性は周囲の絶対湿度に依存し、センサチップ２の周囲の相対湿度は感湿膜１４の抵抗値から判明し、ガスセンサ３０の外部での周囲温度はサーミスタ６２の抵抗値から判明する。そしてカバー３６の内外での気温はほぼ等しいので、サーミスタ６２の抵抗値と感湿膜１４の抵抗値とから、センサチップ２の周囲の絶対湿度を測定できる。この絶対湿度により、金属酸化物半導体膜９の抵抗値を補正し、検出対象ガスの濃度を求める。   The characteristics of the metal oxide semiconductor film 9 depend on the ambient absolute humidity, the relative humidity around the sensor chip 2 is found from the resistance value of the moisture sensitive film 14, and the ambient temperature outside the gas sensor 30 is the resistance of the thermistor 62. From the value. Since the temperature inside and outside the cover 36 is substantially equal, the absolute humidity around the sensor chip 2 can be measured from the resistance value of the thermistor 62 and the resistance value of the moisture sensitive film 14. The resistance value of the metal oxide semiconductor film 9 is corrected by this absolute humidity, and the concentration of the detection target gas is obtained.

図６に、周囲の温度と湿度の変化に対する、フィルタ３８の内側でセンサチップ２の周囲の雰囲気の応答を示す。室温で相対湿度が60%程度の雰囲気から、湿度センサとサーミスタとをフィルタ３８の内側に設置したガスセンサ３０を、温度が35℃で、相対湿度が80%の雰囲気に移し、センサチップ２の周囲の相対湿度と気温とを測定した。気温はガスセンサ３０の外部の気温に追随するが、相対湿度が完全に追随するまで60時間程度経過している。   FIG. 6 shows the response of the atmosphere around the sensor chip 2 inside the filter 38 to changes in ambient temperature and humidity. The gas sensor 30 in which the humidity sensor and the thermistor are installed inside the filter 38 is moved from the atmosphere with a relative humidity of about 60% at room temperature to an atmosphere with a temperature of 35 ° C. and a relative humidity of 80%. The relative humidity and temperature were measured. The temperature follows the temperature outside the gas sensor 30, but about 60 hours have passed until the relative humidity completely follows.

このことは、フィルタ３８が水蒸気を吸収放出するため、センサチップ２の周囲の相対湿度は外部の相対湿度とは異なることを示している。そして図６の状況では、周囲の雰囲気を変えてから数時間程度の間、センサチップ２の周囲では、相対湿度が低い状態が続き、ガスセンサ３０の外部の気温等による補正を施すと、過補正となる。   This indicates that the relative humidity around the sensor chip 2 is different from the external relative humidity because the filter 38 absorbs and releases water vapor. In the situation of FIG. 6, the relative humidity continues to be low around the sensor chip 2 for about several hours after the surrounding atmosphere is changed. If correction is performed based on the temperature outside the gas sensor 30, overcorrection is performed. It becomes.

そこでガスセンサ３０の内部で、センサチップ２の周囲の雰囲気の、相対湿度あるいは絶対湿度を測定すると、ガスセンサ３０の湿度依存性を正確に補正できる。特に、フィルタ３８での水蒸気の吸収／放出のため、センサチップ２の周囲の湿度が外部の湿度に追随するまでの遅れの影響を受けなくなる。センサチップ２はMEMS型なので、感湿膜１４あるいは絶対湿度測定用の追加のヒータ等を設けることは容易で、金属酸化物半導体９を加熱しても感湿膜１４は加熱されないため、高分子感湿膜を用いることができる。また金属酸化物半導体膜９からの放熱量を、ヒータ２４の抵抗値から求めるのではないので、金属酸化物半導体膜９での可燃性ガスの燃焼熱等の影響を受けない。   Therefore, when the relative humidity or absolute humidity of the atmosphere around the sensor chip 2 is measured inside the gas sensor 30, the humidity dependency of the gas sensor 30 can be corrected accurately. In particular, because of the absorption / release of water vapor by the filter 38, it is not affected by the delay until the humidity around the sensor chip 2 follows the external humidity. Since the sensor chip 2 is a MEMS type, it is easy to provide a moisture sensitive film 14 or an additional heater for measuring absolute humidity, and the moisture sensitive film 14 is not heated even when the metal oxide semiconductor 9 is heated. A moisture sensitive film can be used. Further, since the amount of heat released from the metal oxide semiconductor film 9 is not obtained from the resistance value of the heater 24, it is not affected by the combustion heat of the combustible gas in the metal oxide semiconductor film 9.

実施例では金属酸化物半導体ガスセンサを例としたが、支持膜８上に設けた酸化触媒膜で可燃性ガスを燃焼させ、この燃焼熱をヒータ２４の抵抗値から検出する、接触燃焼式ガスセンサでも良い。短時間の直流を加えることにより、感湿膜１４が劣化するおそれがある場合、感湿膜１４に対し専用の２個のパッドを設け、交流を加えることが好ましい。   In the embodiment, a metal oxide semiconductor gas sensor is taken as an example, but a catalytic combustion type gas sensor that combusts a combustible gas with an oxidation catalyst film provided on the support film 8 and detects the combustion heat from the resistance value of the heater 24. good. When there is a possibility that the moisture sensitive film 14 is deteriorated by applying a direct current for a short time, it is preferable to provide two dedicated pads for the moisture sensitive film 14 and apply the alternating current.

２ センサチップ
４ 基板
６ キャビテイ
８ 支持膜
９ 金属酸化物半導体膜
１０〜１３ 脚
１４ 感湿膜
１５，１６ 電極
２０〜２３ パッド
２４ ヒータ
２５，２６ 電極
３０ ガスセンサ
３２ ピン
３４ ベース
３６ カバー
３８ フィルタ
４０，４２ メッシュ
４４ 不織布
５０ 電源
５２ マイクロコンピュータ
５３ ＡＤコンバータ
５４ 駆動部
５５ タイマ
５６ 検出部
５８ 警報部
６０ スイッチ
６２ サーミスタ
R1〜R3 抵抗 2 Sensor chip 4 Substrate 6 Cavity 8 Support film 9 Metal oxide semiconductor film 10-13 Leg 14 Moisture sensitive film 15, 16 Electrode 20-23 Pad 24 Heater 25, 26 Electrode 30 Gas sensor 32 Pin 34 Base 36 Cover 38 Filter 40, 42 Mesh 44 Non-woven fabric 50 Power supply 52 Microcomputer 53 AD converter 54 Drive unit 55 Timer 56 Detection unit 58 Alarm unit 60 Switch 62 Thermistor
R1 ~ R3 resistance

Claims (2)

半導体基板のキャビテイ上に設けられた支持膜に、金属酸化物半導体膜もしくは酸化触媒膜と、ヒータとを設けたセンサチップと、
不要なガスを除去するフィルタと、
前記センサチップとフィルタとを間隔をおいてハウジングに収容し、フィルタを通過した雰囲気をセンサチップへ拡散させるガスセンサにおいて、
前記半導体基板上でかつ前記キャビテイとは異なる位置に、センサチップの周囲の相対湿度を測定する高分子感湿膜が設けられていることを特徴とする、ガスセンサ。 A sensor chip provided with a metal oxide semiconductor film or an oxidation catalyst film and a heater on a support film provided on the cavity of the semiconductor substrate;
A filter that removes unwanted gas,
In the gas sensor that accommodates the sensor chip and the filter in a housing at an interval and diffuses the atmosphere that has passed through the filter to the sensor chip,
A gas sensor, wherein a polymer moisture sensitive film for measuring relative humidity around a sensor chip is provided on the semiconductor substrate at a position different from the cavity . 前記支持膜に、前記金属酸化物半導体膜と、前記ヒータと、前記金属酸化物半導体膜に接続された一対の電極、とが設けられ、The support film is provided with the metal oxide semiconductor film, the heater, and a pair of electrodes connected to the metal oxide semiconductor film,
前記半導体基板上にはさらに、前記高分子感湿膜に接続された一対の電極、及び４個のパッドが設けられ、  On the semiconductor substrate, a pair of electrodes connected to the polymer moisture-sensitive film and four pads are further provided,
前記ヒータの一端と、前記金属酸化物半導体膜に接続された一対の電極の一方と、前記高分子感湿膜に接続された一対の電極の一方とが、第１のパッドに接続され、  One end of the heater, one of the pair of electrodes connected to the metal oxide semiconductor film, and one of the pair of electrodes connected to the polymer moisture sensitive film are connected to the first pad,
前記ヒータの他端が第２のパッドに接続され、前記金属酸化物半導体膜に接続された他方の電極が第３のパッドに接続され、前記高分子感湿膜に接続された他方の電極が第４のパッドに接続されていることを特徴とする、請求項１のガスセンサ。  The other end of the heater is connected to the second pad, the other electrode connected to the metal oxide semiconductor film is connected to the third pad, and the other electrode connected to the polymer moisture sensitive film is The gas sensor according to claim 1, wherein the gas sensor is connected to a fourth pad.
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