JPH04118552A - Method for improving humidity sensor - Google Patents
Method for improving humidity sensorInfo
- Publication number
- JPH04118552A JPH04118552A JP23848390A JP23848390A JPH04118552A JP H04118552 A JPH04118552 A JP H04118552A JP 23848390 A JP23848390 A JP 23848390A JP 23848390 A JP23848390 A JP 23848390A JP H04118552 A JPH04118552 A JP H04118552A
- Authority
- JP
- Japan
- Prior art keywords
- film
- temperature
- humidity
- thin film
- plasma polymerized
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims description 7
- 239000011521 glass Substances 0.000 claims abstract description 6
- 239000000463 material Substances 0.000 claims abstract description 5
- 238000010438 heat treatment Methods 0.000 claims description 11
- 239000000758 substrate Substances 0.000 claims description 11
- 150000003961 organosilicon compounds Chemical class 0.000 claims description 8
- 230000007704 transition Effects 0.000 claims 1
- 230000035945 sensitivity Effects 0.000 abstract description 7
- 238000009833 condensation Methods 0.000 abstract description 5
- 230000005494 condensation Effects 0.000 abstract description 5
- 229920006395 saturated elastomer Polymers 0.000 abstract description 3
- 229920006254 polymer film Polymers 0.000 abstract 2
- 239000010408 film Substances 0.000 description 38
- 239000010409 thin film Substances 0.000 description 9
- 230000009477 glass transition Effects 0.000 description 5
- 239000012528 membrane Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 238000001514 detection method Methods 0.000 description 4
- 229920005597 polymer membrane Polymers 0.000 description 4
- 238000006116 polymerization reaction Methods 0.000 description 4
- 230000006872 improvement Effects 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000000873 masking effect Effects 0.000 description 2
- BFXIKLCIZHOAAZ-UHFFFAOYSA-N methyltrimethoxysilane Chemical compound CO[Si](C)(OC)OC BFXIKLCIZHOAAZ-UHFFFAOYSA-N 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000007791 dehumidification Methods 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 239000005518 polymer electrolyte Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 150000003377 silicon compounds Chemical class 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、湿度センサの改善方法に関する。更に詳しく
は、絶縁性基板上に下部電極、有機けい素化合物プラズ
マ重合膜および上部電極を順次形成せしめた湿度センサ
の改善方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for improving a humidity sensor. More specifically, the present invention relates to a method for improving a humidity sensor in which a lower electrode, an organic silicon compound plasma polymerized film, and an upper electrode are sequentially formed on an insulating substrate.
高分子膜を感湿膜とする静電容量検出型湿度センサは、
高分子電解質を感湿膜とする抵抗検出型のものと比べて
耐水性にすぐれ、相対湿度の検出範囲が広いという特徴
を有しているが、その反面で耐熱性に劣るという欠点も
有している。A capacitance detection type humidity sensor that uses a polymer membrane as a moisture-sensitive membrane is
Compared to resistance detection types that use a polymer electrolyte as a moisture-sensitive membrane, they have superior water resistance and a wider detection range for relative humidity, but they also have the disadvantage of being inferior in heat resistance. ing.
このような欠点を解決させる静電容量検出型湿度センサ
として、絶縁性基板上に形成させた導電性くし型下部電
極の表面を有機けい素化合物プラズマ重合膜で覆い、こ
のプラズマ重合膜上に上部電極を形成させた湿度センサ
が、先に本出願人によって提案されている（特開昭６３
−９５３４７号公報）。As a capacitance detection type humidity sensor that solves these drawbacks, the surface of a conductive comb-shaped lower electrode formed on an insulating substrate is covered with an organosilicon compound plasma polymerized film, and the upper electrode is formed on the plasma polymerized film. A humidity sensor with electrodes formed thereon was previously proposed by the present applicant (Japanese Patent Application Laid-open No. 63
-95347).
このような湿度センサにおいて、下部電極を導電性くし
型電極とせず、第１図に示すようなフラットな薄膜状電
極２を形成させれば、くし型電極を形成させるための複
雑な工程を省略することができると考えた。In such a humidity sensor, if a flat thin film electrode 2 as shown in Fig. 1 is formed instead of using a conductive comb-shaped lower electrode as the lower electrode, the complicated process for forming the comb-shaped electrode can be omitted. I thought it could be done.
そこで、ガラス基板１上にこのような薄膜状下部電極２
を形成させ、その表面を有機けい素化合物プラズマ重合
膜３で覆い、このプラズマ重合膜上に薄膜状上部電極４
を形成させ、薄膜状の上音および下部電極でサンドウィ
ッチされたプラズマ重合膜を有する湿度センサについて
、その感湿習性を測定すると、第２図のグラフに示され
るような結果が得られた。即ち、この結果から、増湿間
を含めて相対湿度０〜１００％の範囲すべてに対し感度
を示すことが確認されたが、同時に感湿時にメきなヒス
テリシスを示すことが分かる。Therefore, such a thin film lower electrode 2 is placed on the glass substrate 1.
is formed, its surface is covered with an organosilicon compound plasma polymerized film 3, and a thin upper electrode 4 is formed on the plasma polymerized film.
When measuring the humidity sensitivity behavior of a humidity sensor having a plasma polymerized film sandwiched between thin upper and lower electrodes, the results shown in the graph of FIG. 2 were obtained. That is, from this result, it was confirmed that sensitivity was exhibited over the entire relative humidity range of 0 to 100%, including during humidification, but at the same time, it was found that a large amount of hysteresis was exhibited when sensing humidity.
本発明の目的は、絶縁性基板上に薄膜状下部電極、有機
けい素化合物プラズマ重合膜および薄膜状上部電極を順
次形成せしめ、薄膜状の上部および下部電極でサンドウ
ィッチされたプラズマ重合膜を有する湿度センサのヒス
テリシス特性を改善する方法を提供することにある。An object of the present invention is to sequentially form a thin film-like lower electrode, an organosilicon compound plasma polymerized film, and a thin film-like upper electrode on an insulating substrate, and to provide a humidity control film having a plasma-polymerized film sandwiched between the thin film-like upper and lower electrodes. An object of the present invention is to provide a method for improving the hysteresis characteristics of a sensor.
かかる本発明の目的は、絶縁性基板上に薄膜状下部電極
、有機けい素化合物プラズマ重合膜および薄膜状上部電
極を順次形成せしめ、薄膜状の上部および下部電極でサ
ンドウィッチされたプラズマ重合膜を、膜形成物質のガ
ラス転移点以上の温度に加熱した後、温度約５０℃以上
、相対湿度約８０２以上の高温高湿雰囲気中に放置し、
湿度センサを改善する方法によって達成される。The object of the present invention is to sequentially form a thin film-like lower electrode, an organosilicon compound plasma polymerized film, and a thin film-like upper electrode on an insulating substrate, and to form a plasma-polymerized film sandwiched with the thin film-like upper and lower electrodes. After heating to a temperature equal to or higher than the glass transition point of the film-forming substance, leave it in a high-temperature, high-humidity atmosphere with a temperature of about 50° C. or higher and a relative humidity of about 802 or higher,
This is achieved by a method of improving humidity sensors.
絶縁性基板上への薄膜状下部電極、有機けい素化合物プ
ラズマ重合膜および薄膜状上部電極の段階的形成は、前
記特許公開公報に記載された如くにして行われる。ただ
し、下部電極は、導電性くし型電極として形成されるの
ではなく、必要に応じてＡｕ／Ｃｒの２層構造として、
フラットな薄膜状電極（全膜厚約２０〜５００ｎｍ）に
形成されるので、煩雑な工程を必要とするフォトリソグ
ラフ法によらなくとも、必要なマスキングを施すだけで
真空蒸着法によって形成させることができる。The stepwise formation of the thin film lower electrode, organosilicon compound plasma polymerized film and thin film upper electrode on the insulating substrate is carried out as described in the above-mentioned patent publication. However, the lower electrode is not formed as a conductive comb-shaped electrode, but as a two-layer structure of Au/Cr as necessary.
Since it is formed as a flat thin film electrode (total film thickness of about 20 to 500 nm), it can be formed by vacuum evaporation by simply applying the necessary masking, without using photolithography, which requires complicated steps. can.
プラズマ重合膜は、薄膜状の上部および下部電極によっ
て一般には部分的にサンドウィッチされた状態となり、
それの改善処理に付される。この改善処理は、プラズマ
重合膜の膜形成材料のガラス転移点以上の温度で約１〜
数時間程度加熱し、室温に放冷後、更に温度５０℃以上
、相対湿度約８０２以上の高温高湿雰囲気中に５時間以
上放置することにより行われる。The plasma polymerized film is generally partially sandwiched between thin film-like upper and lower electrodes.
It will be subject to improvement processing. This improvement treatment is carried out at a temperature above the glass transition point of the film forming material of the plasma polymerized film.
This is done by heating for several hours, allowing to cool to room temperature, and then leaving in a high-temperature, high-humidity atmosphere with a temperature of 50° C. or higher and a relative humidity of about 802 or higher for 5 hours or longer.
プラズマ重合膜のガラス転移点以上の温度での高温処理
は、膜の緻密化および膜硬化を促進させる。膜硬度が低
いと、吸湿により膜が膨潤し、電極間距離が拡がって、
＠湿による誘電率変化分を相殺してしまうが、熱処理を
し、膜を硬化させることで、吸湿による膜の膨潤を抑制
し、その影響を軽減させることができ、この結果として
相対湿度に対する感度が向上するようになる。High temperature treatment at a temperature above the glass transition point of the plasma polymerized film promotes densification and hardening of the film. If the film hardness is low, the film swells due to moisture absorption, and the distance between the electrodes increases.
@This cancels out the dielectric constant change due to humidity, but by heat-treating and curing the film, it is possible to suppress the swelling of the film due to moisture absorption and reduce its influence, and as a result, sensitivity to relative humidity is reduced. will improve.
また、高温高湿雰囲気中への放置は、主としてヒステリ
シスの軽減に効果がみられる。即ち、ヒステリシスの原
因は、主として高温時に吸湿した水分が感湿膜中へ溶解
してしまい、これが減湿時に脱離し難くなるためと考え
られる６
増湿時と減湿時におけるヒステリシスの存在は、感ａ！
膜中における吸着水分子の毛管凝縮に起因する。有機け
い素化合物のプラズマ重合膜においても、中湿度（約４
０〜７０％ＲＨ）以上の雰囲気中においては、水分子は
高分子膜表面に多分子層的に吸着し、特に高湿度域（約
７０％ＲＨ以上）では、＠着水分子が高分子膜表面より
内部に溶解し、毛管凝縮を生ぜしめている。Furthermore, leaving it in a high-temperature, high-humidity atmosphere is mainly effective in reducing hysteresis. In other words, the cause of hysteresis is thought to be that moisture absorbed at high temperatures is dissolved into the moisture-sensitive membrane, and this becomes difficult to release during dehumidification6.The existence of hysteresis during humidification and dehumidification is due to Feeling a!
It is caused by capillary condensation of adsorbed water molecules in the membrane. Plasma-polymerized films of organosilicon compounds are also suitable for medium humidity (approximately 4
In an atmosphere of 0 to 70% RH) or higher, water molecules adsorb onto the surface of a polymer membrane in a multilayered manner, and especially in high humidity areas (approximately 70% RH or higher), water molecules adsorb onto the polymer membrane surface. It dissolves from the surface to the inside, causing capillary condensation.
そこで、予め感湿膜を約５０℃以上、約８０２以上以上
の高温高湿中に長時間放置し、多分子層吸着域における
高分子膜中への水分子の溶解を積極的に生じさせ、ヒス
テリシスの原因となる毛管凝縮を飽和状態とさせること
により、ヒステリシスを軽減することができる。Therefore, the moisture sensitive membrane is left in a high temperature and high humidity of about 50° C. or higher and about 80° C. or higher for a long time to actively cause water molecules to dissolve into the polymer membrane in the multilayer adsorption area. Hysteresis can be reduced by bringing the capillary condensation, which causes hysteresis, into a saturated state.
絶縁性基板上に下部電極、有機けい素化合物プラズマ重
合膜および上部電極を順次形成させた湿度センサにおい
て、下部電極をフラットな薄膜状とすることによりそれ
の形成は容易となるが、ヒステリシスがみられるように
なる。In a humidity sensor in which a lower electrode, an organosilicon compound plasma polymerized film, and an upper electrode are sequentially formed on an insulating substrate, forming the lower electrode into a flat thin film makes it easier to form the lower electrode, but it causes hysteresis. You will be able to do it.
そこで、このような湿度センサを、膜形成物質のガラス
転移点以上の温度に加熱した後、高温高温雰囲気中に放
置することにより、感湿膜が硬化しかつ扱者水分の毛管
凝縮が飽和状態となるため。Therefore, by heating such a humidity sensor to a temperature higher than the glass transition point of the film-forming material and then leaving it in a high-temperature atmosphere, the moisture-sensitive film hardens and the capillary condensation of the operator's moisture reaches a saturated state. To become.
相対湿度に対する感度直線性の向上ならびにヒステリシ
ス特性の大幅な改善が図られる。This improves sensitivity linearity to relative humidity and significantly improves hysteresis characteristics.
次に、実施例について本発明を説明する。 Next, the present invention will be explained with reference to examples.
実施例 第２図に示される形状の湿度センサを作製した。Example A humidity sensor having the shape shown in FIG. 2 was manufactured.
また、ガラス基板上にマスキングを行ない、Ａｕ／Ｃｒ
（７０ｎｍ／３０ｎ園）２層構造のフラットな薄膜状下
部電極を蒸着法によって形成させた。この下部電極形成
ガラス基板を、外部電極型プラズマ重合装置のベルジャ
内に設置し、ベルジャ内をＩ Ｘ １０”３Ｔｏｒｒ以
下迄排気した後、メチルトリメトキシシランモノマーを
導入し、圧力が設定値になる迄モノマー流量を増加させ
た。圧力が一定となった時点で放電を開始し、プラズマ
重合を行った。なお、反応圧力の設定に際し、モノマー
蒸気の流量計の読みも常に一定となるよう、排気系のメ
インバルブでベルジャ内圧力を調節した。In addition, masking was performed on the glass substrate, and Au/Cr
(70 nm/30 nm) A flat thin film lower electrode with a two-layer structure was formed by vapor deposition. This lower electrode-formed glass substrate was placed in the bell jar of an external electrode type plasma polymerization apparatus, and after the bell jar was evacuated to below I x 10"3 Torr, methyltrimethoxysilane monomer was introduced and the pressure reached the set value. The monomer flow rate was increased until the pressure became constant. When the pressure became constant, discharge was started and plasma polymerization was performed. In addition, when setting the reaction pressure, exhaust gas was The pressure inside the bell jar was regulated using the main valve of the system.
形成されるプラズマ重合膜の膜厚は、重合時間（〜３０
分間）に対しほぼ比例関係にあり、その成長速度は、反
応圧力０．０８Ｔｏｒｒ、放電出力６０１１のとき約２
６ｎｍ／分であった。このため、感湿膜となるプラズマ
重合膜の膜厚は１重合時間によって制御することとし、
本実施例では膜厚６３〜９８０ｎ−のものを形成させた
。The thickness of the plasma polymerized film formed depends on the polymerization time (~30
minute), and the growth rate is approximately 2 when the reaction pressure is 0.08 Torr and the discharge output is 6011.
It was 6 nm/min. For this reason, the film thickness of the plasma polymerized film that becomes the moisture-sensitive film is controlled by one polymerization time.
In this example, a film thickness of 63 to 980 n- was formed.
更に、プラズマ重合膜上には、 Ａｕの蒸着膜からなる
上部電極を形成せしめ、ただし上部電極には透湿性が求
められるため、その膜厚は約２０ｒ＋＋ａとした。Furthermore, an upper electrode made of a vapor-deposited Au film was formed on the plasma polymerized film, but since the upper electrode was required to have moisture permeability, the film thickness was set to about 20r++a.
このようにして作製された、プラズマ重合膜感湿膜が薄
膜状の上部および下部電極によってサンドウィッチされ
た湿度センサは、９０℃で約１時間予備加熱された後、
メチルトリメトキシシランのプラズマ重合膜のガラス転
移点（約１５０℃）以上の温度である２００℃で８時間
加熱された。これを室温迄放冷した後、６５℃、９５％
ＲＨの高温高温雰囲気中に２７時間放置した。The humidity sensor prepared in this way, in which the plasma polymerized moisture-sensitive film was sandwiched between thin film-like upper and lower electrodes, was preheated at 90°C for about 1 hour, and then
It was heated for 8 hours at 200° C., which is a temperature higher than the glass transition point (approximately 150° C.) of the plasma polymerized film of methyltrimethoxysilane. After cooling this to room temperature, 65℃, 95%
It was left in a high temperature RH atmosphere for 27 hours.
（感湿特性）
第３図：感湿膜膜厚８００ｎｍのものを用い、２００℃
の加熱処理後のもの
第２図と比較して、相対湿度に対する
感度直線性が向上していることが分が
る
第４図１上記加熱処理後、高温高湿雰囲気中に放置した
もの
ヒステリシス特性が大幅に改善されて
いることが分かる
第５図：感湿膜膜厚８００ｎ■のものを用い、加熱処理
することなく、高温高湿雰囲気中
への放置（６０℃、９０％ＲＨ，１１７時間）した前（
０）および後（・）
加熱処理しないと、ヒステリシス特性
の改善が殆んどみられないことが分か
る(Moisture-sensitive characteristics) Figure 3: Using a moisture-sensitive film with a thickness of 800 nm, at 200°C
It can be seen that the sensitivity linearity with respect to relative humidity has improved compared to the one after heat treatment in Figure 2. Figure 4: After the above heat treatment, the one left in a high temperature and high humidity atmosphere Hysteresis characteristics Figure 5 shows that the moisture-sensitive film thickness is 800 nm and is left in a high-temperature, high-humidity atmosphere (60°C, 90% RH, 117 hours) without heat treatment. ) before (
0) and after (・) It can be seen that there is almost no improvement in hysteresis characteristics without heat treatment.
第１図は、本発明で用いられる湿度センサの一態様の平
面図である。第２図は加熱処理および高温高温放置され
ないものの、第３図は加熱処理だけされたものの、第４
図は加熱処理および高温高湿放置されたものの、第５図
は高温高湿放置だけがされたものの、いずれも感湿特性
を示すグラフ（符号の説明）
１・・・・・絶縁性基板
２・・・・・薄膜状下部電極
３・・・・・プラズマ重合膜
４・・・・・薄膜状上部電極FIG. 1 is a plan view of one embodiment of a humidity sensor used in the present invention. Figure 2 shows that the heat treatment and high-temperature exposure were not performed, while Figure 3 shows that the heat treatment was only performed, but the fourth
The figure shows heat treatment and exposure to high temperature and high humidity, while the figure 5 shows only exposure to high temperature and humidity, both are graphs showing moisture sensitivity characteristics (explanation of symbols) 1...Insulating substrate 2 ... Thin film lower electrode 3 ... Plasma polymerized film 4 ... Thin film upper electrode
Claims (1)
プラズマ重合膜および薄膜状上部電極を順次形成せしめ
、薄膜状の上部および下部電極でサンドウィッチされた
プラズマ重合膜を、膜形成物質のガラス転移点以上の温
度に加熱した後、温度約５０℃以上、相対湿度約８０％
以上の高温高湿雰囲気中に放置することを特徴とする湿
度センサの改善方法。1. A thin film-like lower electrode, an organosilicon compound plasma polymerized film, and a thin film-like upper electrode are sequentially formed on an insulating substrate, and the plasma polymerized film sandwiched between the thin film-like upper and lower electrodes is coated with glass as a film-forming material. After heating to a temperature above the transition point, the temperature is about 50℃ or more, and the relative humidity is about 80%.
A method for improving a humidity sensor, which is characterized by leaving it in a high-temperature, high-humidity atmosphere as described above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23848390A JP2959083B2 (en) | 1990-09-07 | 1990-09-07 | How to improve the humidity sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23848390A JP2959083B2 (en) | 1990-09-07 | 1990-09-07 | How to improve the humidity sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04118552A true JPH04118552A (en) | 1992-04-20 |
| JP2959083B2 JP2959083B2 (en) | 1999-10-06 |
Family
ID=17030915
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23848390A Expired - Fee Related JP2959083B2 (en) | 1990-09-07 | 1990-09-07 | How to improve the humidity sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2959083B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006349667A (en) * | 2005-05-19 | 2006-12-28 | Nippon Soken Inc | Method for manufacturing humidity sensor |
-
1990
- 1990-09-07 JP JP23848390A patent/JP2959083B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006349667A (en) * | 2005-05-19 | 2006-12-28 | Nippon Soken Inc | Method for manufacturing humidity sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2959083B2 (en) | 1999-10-06 |
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