1283297 九、發明說明： 【發明所屬技術領域】 本發明係關於一種感測器，特別是一整合濕度感測器、溫度 感測器、加熱器及量測電路，並且以互補金屬氧化物半導體(CMOS) 方式製成之整合型感測器。 【先前技術】 .濕度感測器已被廣泛應用於一般日常生活中，在工業上的使 用也無所不在，包括半導體工業、液晶產業等也需要濕度感測器 。此外，電容變化之感測方式已被廣泛應用於濕度、加速度、壓 力、氣體、流體等感測器中，隨著微機電系統及半導體技術之進 步與成長，除了可精確定義微結構的尺寸與層級，且可將訊號轉 換電路整合至同一晶片上，可減少面積、降低雜訊及減低消耗功 率。 在濕度感測器相關硏究，電容式濕度計使用之感濕材料爲疏 水性高分子，水分子容易在內部凝結產生磁滯現象(hysteresis)。電 阻式濕度感測器之感濕材料爲親水性高分子，如果長期在結霧狀 態和高濕度環境下使用，其特性會因高分子被水溶解而改變原本 特性。是以，電容式及電阻式濕度感測器相互比較，電容式的靈 敏度較高且具有低耗電量的特點。 關於電容式濕度感測器的製作與結構，可以在n-Si基板的板 面及底面蒸鍍Au電極’並在表面旋塗上polyimide(聚亞醢胺)作爲 Ί283297 感濕材料，此感濕材料藉著水氣的吸附而改變自身的介電常數， 經由量測電容變化推得相對濕度値，感測器的大小爲 5.5mmx4.5mm 〇 另一電容式濕度感測器的製作與結構，係用標準的CM0S製 程來製作濕度感測器。其利用polyimide及BCB薄膜作爲感濕材 料，並且加入heater(加熱器)用來去除凝結在薄膜表面的水氣，使 反應效率更好及更精確，此種感測器大小爲3mmx3mm，其體積明 φ ^顯比前一感測器小。 在電容式濕度感測器歷年的硏究中，大多強調在感測器結構 上的變化與加強，或加入溫度感測器，或加入加熱器作爲溫度補 償，再者或加入電路做爲量測之用。目前並無針對同時把濕度感 測、溫度感測、加熱器及量測電路同時整合。 【發明內容】 φ 本發明利用半導體製程之微機電技術，製作整合型溫度、濕 度、加熱器及電路之微感測器。此感測器可同時感測溫度及濕度 變化，並因爲加入訊號放大電路用以直接讀取感測訊號，所以不 需要再外加訊號轉換電路。換言之，係指一晶片再透過後加工處 理移除犧牲層，使用反應性離子蝕刻(Reactive ion etch，RIE)法， - 移除二氧化矽(Silicon oxide)層，再移除部分的矽基材，再旋塗上 ‘ 負型光阻型的polyimide，經由曝光顯影製程，定義感濕區域’完 成濕度感測器及溫度感測器之結構。且在上述製程中加入訊號處 6 » !283297 理電路。 換言之，本發明是將每個感測器的特性整合，利用半導體製 程技術’使之整合在同一片晶片上，不但可以減少其訊號的損失 ’也可以降低成本及增加感測的精準度。本發明的結構包括： 一濕度感測電極，係用CMOS製程之鋁層當作感測電極，以 梳狀的型式增加其感測電容大小，最後將犧牲層移除，塗上吸濕 材料即完成濕度感測的結構部分。 % 一加熱器，係由多晶矽製成，並將該加熱器設計於電容電極 的底端，如此會有較好的加熱效率，有助於提高濕度感測的精確 度。 至少一訊號處理電路，凡是可將電容訊號處理轉換之電路皆 可，整合於該電容式濕度感測器內。 一溫度感測器，可以是一熱敏電阻型溫度感測器，其利用半 導體材料(n-well，polysilicon等)易受溫度變化而改變其電阻的特性 φ ，來量測溫度的變化。或是一熱電堆型溫度感測器，其使用P型 與η型串聯結構，透過溫度的變化產生電壓差的變化。 【實施方式】 請參閱第一圖及第二圖所示，係用CMOS製程之鋁層當作感 測電極12。該電極12係使用兩組梳狀電極(Interdigitated electrodes)14、16。梳狀電極14、16的結構型式可以增加感測電 容的大小。於該電極12製作完成後，再將預定的犧牲層移除，並 7 1283297 在該電極I2上層係可旋塗感濕材料層，在本發明之應用實施例中 可以聚亞醯胺(polyimide)作爲感濕材料，即完成濕度感測的結構部 分。 又該電極12的底部係加入一多晶矽加熱器18。將加熱器設 計於電容電極的底端，該加熱器18提供垂直型式的加熱效果，會 有較好的加熱效率，有助於提高濕度感測的精確度。 在上述的結構中，吾人可以使用四層金屬層厚度約6/zm爲 • 電容電極，且其面積爲l.Ommxl.Omm。設計較大及較厚的電極可 增加電容量及靈敏度，此外，可加入接地線(ground line)的設計， 來減少寄生電容對濕度感測電容的影響。 請參閱第三A圖及第三B圖所示，一溫度感測器20，可以是 熱電堆(Thermopile)感應方式。熱電堆(Thermopile)的設計原理是利 用Seebeck效應。其原理爲金屬材料內部存在不同的溫度差，則 會產生不同的熱電動勢，若將兩種不同金屬相接在一起，給予兩 ® 端有不同之溫度，則會有電壓差的訊號產生。更進一步而言，係 使用P型材料22與N型材料24串聯結構，透過溫度差的變化產 生電壓變化。 請參閱第四A圖及第四B圖所示。另一溫度感測器21，可以 是熱敏電阻(Thermoresistive)的感測方式。在熱敏電阻的材料選擇 上，由於半導體所使用的材料裡，以n-well 23之電阻溫度係數 (丁emperature coefficient of resistance ’ TCR)値最大’在筒溫區之 8 1283297 變化斜率最大，因此很適合用於當作熱敏電阻材料。爲了減少熱 敏電阻的非線性誤差，所以吾人將電阻並聯來提高線性度。在本 實施例中所設計之電阻値，未加熱時爲9〇kQ。 由於該濕度感測器與該溫度感測器一體，所以請參閱第五A 、五B、五C圖，經過半導體廠代工的晶片必需再透過後加工處 理移除犧牲層。其製程上使用反應性離子蝕刻(Reactive ion etch， RIE)法30，移除二氧化砂(Silicon oxide)層32，再移除部分的砂基 • 材(虛線所示)34，再旋塗上負型光阻型的polyimide。經由曝光顯 影製程定義感濕區域，即完成濕度感測器及溫度感測器之結構。 請參閱第六A圖所示，一訊號處理電路40係用以處理感濕 電極的電容變化。該訊號處理電路40是經由功率放大器轉換成電 壓訊號輸出，並可透過差動電阻對後級作驅動。請參閱第六B圖 ，另一訊號處理電路41是三個反向器所構成之振盪器，經由感濕 電極的電容變化，使電路的震盪頻率改變，利用頻譜儀量測其頻 ^ 率變化。以上各電路的製作乃是藉由CMOS的製程而完成。 以本發明的晶片結構而言，請參閱第二圖所示，包括一個基 板50 ’該基板50設有一電容式的濕度感測器52。請參閱第一圖 ’該濕度感測器52具有梳狀形式的電極14、I6，據此可以增加所 _ 能感測之電容値的大小。此外在該電極14、16上塗有感濕材料層 ，例如聚亞醯胺。 請參閱第三A、三B圖，一溫度感測器20係與該濕度感測器 1283297 52同時製成。該溫度感測器20可以是熱電堆的感測方式。另外， 請參閱第四A、四B圖，一溫感測器21可以是熱敏電阻的感測方 式0 請參閱第二圖，一加熱器ls係置設在該電容電極14、16的 底部。該加顯18是-多㈣材_成，細位在_度感測器 52的底面，所以該加熱器18提供垂直加熱效果。不但會有較好的 加熱效率，也有助於提局濕度感測的精確度。 請參閱第六A圖或第六B圖，—訊號處理電路4〇或41係整 合在該晶片內。其可以是由三個反相器所組成，或是由功率放大 器組成。 縱上所述’本發明利用半導體製程微機電技術所設計之感測 器’不僅能將兀件微小化’且具有低耗電、高敏度、低溫度係數 、高穩定度、低磁滯現象及反應時間快等優點，未來在產業應用 上必有很高之可行性。 1283297 【圖式簡單說明】 第一圖係本發明濕度感測器之電極結構示意圖。 第二圖係本發明之晶片結構示意圖。 第三A圖係本發明熱電堆式溫度感測器結構示意圖。 第三B圖係第三A圖中之A— A剖面示意圖。 第四A圖係本發明熱敏電阻示意圖。 第四B圖係本發明熱敏電阻結構示意圖。 Φ 第五A〜五C圖係本發明之晶片經蝕刻之結製程示意圖。 第六A圖係本發明之訊號處理電路圖之一。 第六B圖係本發明之訊號處理電路圖之二。 【圖號說明】 12感測電極 φ 14、16梳狀電極 18加熱器 20、21溫度感測器 22 P型材料 23 n-well 24 N型材料 30反應性離子蝕刻 32二氧化矽層 π 1283297 34矽基材 40、41訊號處理電路 50基板 52濕度感測器1283297 IX. DESCRIPTION OF THE INVENTION: 1. Field of the Invention The present invention relates to a sensor, particularly an integrated humidity sensor, a temperature sensor, a heater, and a measuring circuit, and is a complementary metal oxide semiconductor ( Integrated sensor made in CMOS). [Prior Art] Humidity sensors have been widely used in general daily life, and their use in industry is also ubiquitous, including humidity sensors in the semiconductor industry and the liquid crystal industry. In addition, the sensing method of capacitance change has been widely used in sensors such as humidity, acceleration, pressure, gas, fluid, etc. With the advancement and growth of MEMS and semiconductor technology, in addition to precisely defining the size of microstructures and Level, and the signal conversion circuit can be integrated on the same chip, which can reduce the area, reduce noise and reduce power consumption. In the humidity sensor related research, the moisture sensitive material used in the capacitive hygrometer is a hydrophobic polymer, and the water molecules easily condense inside to cause hysteresis. The moisture sensitive material of the resistive humidity sensor is a hydrophilic polymer. If it is used in a fogging state and a high humidity environment for a long period of time, its properties may change due to the dissolution of the polymer by water. Therefore, capacitive and resistive humidity sensors are compared with each other, and the capacitive sensitivity is high and the power consumption is low. Regarding the fabrication and structure of the capacitive humidity sensor, the Au electrode can be evaporated on the plate surface and the bottom surface of the n-Si substrate, and polyimide (polyimide) can be spin-coated on the surface as the Ί283297 moisture sensitive material. The material changes its dielectric constant by the adsorption of moisture, and the relative humidity is measured by measuring the change of capacitance. The size of the sensor is 5.5mmx4.5mm. The fabrication and structure of another capacitive humidity sensor. A humidity sensor is fabricated using a standard CM0S process. It uses polyimide and BCB film as the moisture sensitive material, and adds a heater to remove the moisture condensed on the surface of the film, so that the reaction efficiency is better and more accurate. The size of the sensor is 3mm x 3mm, and its volume is clear. φ ^ is smaller than the previous sensor. In the research of capacitive humidity sensors over the years, most of the emphasis on the changes and enhancements in the structure of the sensor, or adding a temperature sensor, or adding a heater as a temperature compensation, or adding a circuit as a measurement Use. At the same time, there is no simultaneous integration of humidity sensing, temperature sensing, heater and measuring circuits. SUMMARY OF THE INVENTION φ The present invention utilizes microelectromechanical technology of a semiconductor process to fabricate integrated microsensors for temperature, humidity, heaters, and circuits. The sensor can sense temperature and humidity changes at the same time, and because the signal amplifying circuit is added to directly read the sensing signal, no additional signal conversion circuit is needed. In other words, it refers to a wafer after re-transmission processing to remove the sacrificial layer, using reactive ion etching (RIE), removing the layer of germanium oxide, and removing part of the germanium substrate. Then, the 'negative photoresist type polyimide is spin-coated, and the humidity sensing area is defined by the exposure development process to complete the structure of the humidity sensor and the temperature sensor. And in the above process, add the signal 6 » !283297 circuit. In other words, the present invention integrates the characteristics of each sensor and integrates it on the same wafer using semiconductor process technology, which not only reduces the loss of its signal, but also reduces the cost and increases the accuracy of sensing. The structure of the present invention comprises: a humidity sensing electrode, which uses a CMOS process aluminum layer as a sensing electrode, increases the sensing capacitance in a comb-like pattern, and finally removes the sacrificial layer and applies the moisture absorbing material. Complete the structural part of the humidity sensing. % A heater is made of polysilicon and the heater is designed at the bottom of the capacitor electrode. This will result in better heating efficiency and help to improve the accuracy of humidity sensing. At least one signal processing circuit, any circuit that can convert the capacitance signal processing, is integrated into the capacitive humidity sensor. A temperature sensor, which may be a thermistor type temperature sensor, measures the change in temperature by using a semiconductor material (n-well, polysilicon, etc.) which is susceptible to temperature changes and changes its resistance characteristic φ. Or a thermopile type temperature sensor that uses a P-type and an n-type series structure to change the voltage difference through the change in temperature. [Embodiment] Referring to the first and second figures, the aluminum layer of the CMOS process is used as the sensing electrode 12. The electrode 12 uses two sets of interdigitated electrodes 14, 16. The configuration of the comb electrodes 14, 16 can increase the magnitude of the sensing capacitance. After the electrode 12 is completed, the predetermined sacrificial layer is removed, and 7 1283297 is layered on the electrode I2 to spin-coat the moisture-sensitive material layer. In the application example of the present invention, polyimide can be used. As the moisture sensitive material, the structural part that completes the humidity sensing. Further, the bottom of the electrode 12 is charged with a polysilicon heater 18. The heater is designed at the bottom end of the capacitor electrode. The heater 18 provides a vertical type of heating effect, which has better heating efficiency and helps to improve the accuracy of humidity sensing. In the above structure, we can use four layers of metal layers with a thickness of about 6/zm as the capacitor electrode and an area of 1.0 mm x 1.0 mm. Designing larger and thicker electrodes increases capacitance and sensitivity. In addition, a ground line design can be added to reduce the effects of parasitic capacitance on the humidity sensing capacitance. Referring to FIG. 3A and FIG. 3B, a temperature sensor 20 may be a thermopile sensing method. The design principle of Thermopile is to use the Seebeck effect. The principle is that there are different temperature differences inside the metal material, which will produce different thermoelectromotive forces. If two different metals are connected together and different temperatures are given to the two ® terminals, a voltage difference signal will be generated. Further, a P-type material 22 is used in series with the N-type material 24, and a change in temperature difference causes a voltage change. Please refer to the fourth A picture and the fourth B picture. Another temperature sensor 21 may be a sensing method of a thermistor. In the material selection of the thermistor, the material used in the semiconductor has the highest temperature gradient of the n-well 23 temperature coefficient (Temperature coefficient of resistance 'TCR) 値max. Very suitable for use as a thermistor material. In order to reduce the nonlinearity error of the thermistor, we have paralleled the resistors to improve linearity. The resistor 设计 designed in this embodiment is 9 〇 kQ when it is not heated. Since the humidity sensor is integrated with the temperature sensor, please refer to Figures 5A, 5B, and 5C. The wafers that have been manufactured by the semiconductor factory must be removed by post-processing to remove the sacrificial layer. A reactive ion etch (RIE) method 30 is used in the process to remove the silica oxide layer 32, and then a portion of the sand substrate (shown by dashed lines) 34 is removed, and then spin-coated. Negative photoresist type polyimide. The wetted area is defined by an exposure development process, that is, the structure of the humidity sensor and the temperature sensor is completed. Referring to Figure 6A, a signal processing circuit 40 is used to process the change in capacitance of the wetted electrode. The signal processing circuit 40 is converted into a voltage signal output via a power amplifier, and can be driven to the subsequent stage through a differential resistor. Referring to FIG. 6B, the other signal processing circuit 41 is an oscillator composed of three inverters, and the oscillation frequency of the circuit is changed by the capacitance change of the sensing electrode, and the frequency change is measured by the spectrum analyzer. . The above circuits are fabricated by a CMOS process. In the wafer structure of the present invention, as shown in the second figure, a substrate 50' is included. The substrate 50 is provided with a capacitive humidity sensor 52. Referring to the first figure, the humidity sensor 52 has electrodes 14 and I6 in the form of a comb, whereby the size of the capacitance 感 that can be sensed can be increased. Furthermore, the electrodes 14, 16 are coated with a layer of a moisture-sensitive material, such as polyamine. Referring to Figures 3A and 3B, a temperature sensor 20 is fabricated simultaneously with the humidity sensor 1283297 52. The temperature sensor 20 can be a sensing mode of the thermopile. In addition, please refer to FIG. 4A and FIG. 4B. The temperature sensor 21 can be the sensing mode of the thermistor. Referring to the second figure, a heater ls is disposed at the bottom of the capacitor electrodes 14 and 16. . The addition 18 is - (four) material, and the fine position is on the bottom surface of the _ degree sensor 52, so the heater 18 provides a vertical heating effect. Not only will there be better heating efficiency, but it will also help to improve the accuracy of humidity sensing. Referring to Figure 6A or Figure 6B, the signal processing circuit 4A or 41 is integrated into the wafer. It can consist of three inverters or a power amplifier. In the above, the sensor designed by the semiconductor process micro-electromechanical technology of the present invention can not only miniaturize the device, but also has low power consumption, high sensitivity, low temperature coefficient, high stability, low hysteresis and The reaction time is fast and so on, and it will have high feasibility in industrial application in the future. 1283297 [Simple description of the drawings] The first figure is a schematic diagram of the electrode structure of the humidity sensor of the present invention. The second drawing is a schematic view of the structure of the wafer of the present invention. The third A is a schematic structural view of the thermopile type temperature sensor of the present invention. The third B diagram is a schematic view of the A-A section in the third A diagram. The fourth A diagram is a schematic diagram of the thermistor of the present invention. The fourth B diagram is a schematic diagram of the structure of the thermistor of the present invention. Φ Fifth A to C C is a schematic diagram of the etched junction process of the wafer of the present invention. Figure 6A is one of the signal processing circuit diagrams of the present invention. The sixth B diagram is the second signal processing circuit diagram of the present invention. [Description of the figure] 12 sensing electrode φ 14, 16 comb electrode 18 heater 20, 21 temperature sensor 22 P type material 23 n-well 24 N type material 30 reactive ion etching 32 ruthenium dioxide layer π 1283297 34矽 substrate 40, 41 signal processing circuit 50 substrate 52 humidity sensor