TWI325054B - Gas sensor with diffuse micro cavity structure and method thereof - Google Patents

Description

1^25054 IX. Description of the invention: [Technical field to which the invention belongs] The cavity is a single type of money machine, especially a gas sensor with a diffusion micro-air &amp; early detection. [Prior Art] The 値 値 sewing 11 towel, the cleavage material has a long-term f: number easy to be compatible with the application module integration. Because the solid = ΐ ΪΪΓΪ ” 体 体 体 体 体 : : : : : : : : : : : : : : : : : : : : : : 质量 质量 质量 质量 质量 质量 质量 质量 质量 质量 质量 质量 质量 质量 质量 质量 质量 质量2ΐ Under the wind speed and spoiler environment, the reproduction stability of the 3 f sensing output signal is required to achieve the stability of the output signal. It is susceptible to the sensing and maintenance of the solid electrolyte material. However, its size still does not meet the market's 1 3W, and the demand for the potential and the power consumption of the sensor are generally greater than ., /, the power is too large and is not suitable for portable products. The three figures are structural diagrams of a conventional diffusion gas sensor 30 that utilizes a porous structural layer 33 to coat the electrode 32 to the sensing material layer 31 to make a specific gas The molecule can improve the reliability of the sensor through the porous structural layer 33. The porous structural layer 33 is made by sintering, but the pore distribution and the gas permeability are controlled by the sintering of the material, so that the application is It is difficult. The fourth figure is a schematic view of a conventional micropore cover gas sensor, which utilizes a microporous ceramic cover to "join 5 1325054 sensing material layer 41 and surround an electrode 42. The specific gas molecules can pass through the microporous ceramic cover 43 to improve the reliability of the sensor. Wherein the microporous ceramic cover 43 is provided with a hole 431 for allowing the gas to be detected to pass, but the diameter of the hole 431 is less than 20&quot; m, and the minimum precision of the thick film is 50# m, so the process It is difficult to produce a hole having a precision of 20/m in the microporous ceramic cover 43. In addition, the conventional technique is ceramic lamination sintering, and the microcavity volume and the diffusion hole are easily deformed and difficult to control. Moreover, the heater is transferred onto the sensing substrate, so the heat conduction is not uniform. SUMMARY OF THE INVENTION An object of the present invention is to provide a gas sensor having a diffusion microcavity unit which is less susceptible to interference from ambient airflow and which can improve reliability. A second object of the present invention is to provide a gas sensor having a diffusing microcavity unit that detects uniform reproducibility of gas diffusion sampling. It is still another object of the present invention to provide a gas sensor having a diffusion microcavity unit that is miniaturized and power-saving. A gas sensor for achieving the above object, comprising a sensing unit comprising a sensing substrate, the sensing substrate having an upper surface and a lower surface, the upper surface being provided with a first sensing electrode, and the upper surface a second sensing electrode is disposed on the lower surface, wherein the sensing substrate is embedded with a plurality of conductive electrodes and a plurality of heaters, the conductive electrodes are connected to the heater; and a microcavity unit is fixed on the Above the sensing unit, a microcavity is formed between the microcavity unit and the sensing substrate, and a diffusion hole is disposed on the microcavity unit. A method for fabricating a gas sensor for achieving the above object comprises: forming a microcavity unit, and forming a diffusion hole on the microcavity unit; and fabricating a 6" material: the upper and lower surfaces of the sensing substrate are disposed a first sensing strip, a first sensing electrode, a plurality of conductive surfaces and a plurality of heatings H embedded in the sensing substrate; and a connecting cavity unit and a sensing base. The micro-electromechanical processing method is used to fabricate a microcavity k to form a diffusion hole, and the microcavity body and the diffusion hole form a microcavity single; the sensing of the thick film powder is performed by a knife forming technique a sensing base: a method of electromechanical processing embedding a plurality of conductances in a sensing substrate to form a sensing unit; and using the microcavity: a top structure and using the sensing unit as a bottom of the gas sensing benefit Structure, and anodic bonding or material eutectic ^ 2 the microcavity unit and the sensing unit are jointly packaged into a ceramsite:: type cattle to form the gas sensing crying of the diffusion microcavity unit of the present invention It is necessary to sense the high temperature of the thick film powder; in rtrr, to detect the gas expansion Dissipating - forming a gas heater and conducting electrodes to fabricate a gas sensor base is an embodiment. [The present invention will be described with reference to a preferred embodiment of the present invention. Understand that the person familiar with this turtle can modify the invention of this article, _ get the person =: understand T describes the person who is familiar with the skill of the bank = two widely disclosed, and its content is not to limit the invention.", · , Γ Γ = : ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Please refer to the first figure for a structural diagram of a gas sensor with a diffusion microcavity unit. The gas sensor 10 includes a sensing unit 11 and a microcavity unit 12, and the microcavity unit 12 is The top structure and the sensing unit 11 are bottom structures, that is, the microcavity unit 12 is fixed above the sensing unit 11 . A microcavity 101 is disposed between the microcavity unit 12 and the sensing unit 11, and the microcavity unit 12 and the sensing unit 11 are sealed as the gas sensor 10. The sensing unit 11 includes a sensing substrate (sensing substrate) 13, a first sensing electrode, and a plurality of conductive electrodes 16 and a plurality of heaters. The sensing substrate 13 of the unit is a ceramic-based sensing substrate having a thickness of 5-30/m, and the functional sensing thick film powder such as vaporized #oxygen conductor is made at a high temperature to make the sensing. The substrate 13 senses the content of a specific gas contained in the microcavity 101 such as carbon monoxide, carbon dioxide, oxygen, etc. In the following embodiments, the present invention is implemented in an oxygen sensing gas sensor. The measuring substrate 13 has an upper surface 131 and a lower surface 132. The upper surface 131 is provided with a first sensing electrode 14, and the lower surface 132 is provided with a second sensing electrode 15. The first and second sensing electrodes 14, 15 is connected to an external circuit (not shown) so that the external circuit can convert the oxygen concentration in the air by sensing the amount of current of the first and second sensing electrodes 131, 132. A plurality of silly 16 and a plurality of heaters 17 are embedded in the sensing substrate 13 . Preferably, the feeling is The measuring substrate 13 is provided with the conductive electrode 16 and the heater 17 on both end sides. The heater 17 is connected and combined with the conductive electrode 16. Therefore, an external power source is supplied to the heater 17 by the conductive electrode 16. The heater 17 generates a heat source to increase the temperature of the sensing substrate film 13 and increase the efficiency of gas sensing. In other words, the heater 17 is controlled by a controller (not shown) to make the heater 17 </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; It is limited to the embodiments of the embodiments set forth in the specification.

Claims (1)

1325054 X. Patent Application Range: 1. A gas sensor with a diffusion microcavity unit, comprising: a sensing unit comprising a sensing substrate, the sensing substrate having an upper surface and a lower surface, a first sensing electrode is disposed on the upper surface, and a second sensing electrode is disposed on the lower surface, wherein the sensing substrate is embedded with a plurality of conductive electrodes and a plurality of heaters, and the conductive electrode is connected to the heater; And a microcavity unit is fixed on the sensing unit, and forms a microcavity between the microcavity unit and the sensing substrate, and the microcavity unit is provided with a diffusion hole. 2. A gas sensor having a diffusion microcavity unit according to claim 1, wherein the microcavity unit is in the form of glass, twin crystal and its surface mineral film. 3. A gas sensor having a diffusion microcavity unit as claimed in claim 1 wherein the diameter of the diffusion hole is less than 20#111. 4. A gas sensor having a diffusion microcavity unit according to claim 1 wherein the sensing substrate is comprised of an oxygen ion conductor. 5. A gas sensor having a diffusing microcavity unit according to claim 4, wherein the oxygen ion guiding system is cerium oxide. 6. The gas sensor of the diffusing microcavity unit as claimed in claim 1 or 4, wherein the sensing substrate has a thickness of 5-30 // m. 7. A method of fabricating a gas sensor with a diffusion microcavity unit, comprising: fabricating a microcavity unit and forming a diffusion hole in the microcavity unit; and fabricating a sensing substrate a first sensing electrode and a second sensing electrode are disposed on the upper and lower surfaces of the sensing substrate, and 13 1325054 is embedded in the sensing substrate, and a plurality of conductive electrodes and a plurality of heaters are connected; and the microcavity unit is connected to the Sensing the substrate. 8. The method of fabricating a gas sensor having a diffusion microcavity unit according to claim 7, wherein the microcavity unit is a glass, a twin crystal structure and a surface coating film. 9. The method of fabricating a gas sensor having a diffusion microcavity unit according to claim 7 wherein the diameter of the diffusion hole is less than 20 &quot; m. 10. The method of fabricating a gas sensor having a diffusion microcavity unit according to claim 7, wherein the sensing substrate is an oxygen ion conductor. 11. The method of fabricating a gas sensor having a diffusion microcavity unit according to claim 10, wherein the oxygen ion guiding system is zirconia. 12. The method of fabricating a gas sensor having a diffusion microcavity unit according to claim 7 or 10, wherein the sensing substrate has a thickness of 5-30 // m. 13. The method of fabricating a gas sensor having a diffusing microcavity unit according to claim 7, wherein the method of fabricating the microcavity unit comprises fabricating in a microelectromechanical process. 14. The method of fabricating a gas sensor having a diffusion microcavity unit according to claim 13 wherein the MEMS processing method is a low temperature CMOS/MEMS processing method. 15. The method of fabricating a gas sensor having a diffusing microcavity unit according to claim 7, wherein the sensing substrate is made of a ceramic powder system. 16. The method of fabricating a gas sensor with a diffusion microcavity unit according to claim 7, wherein the sensing substrate is formed into the sensing substrate by a doctor blade forming method. . A method of fabricating a gas sensor having a diffusing microcavity unit according to claim 7 wherein the heater is co-fired in the interior of the sensing substrate. 18. The method of fabricating a gas sensor having a diffusion microcavity unit according to claim 7, wherein the microcavity unit and the sensing unit are combined with an anode. 19. The method of fabricating a gas sensor having a diffusion microcavity unit according to claim 7, wherein the microcavity unit and the sensing unit are combined in a eutectic manner. 15 1325054 .....·ι·.... I..··· . . 丨 (The format, order and bold text of this manual should not be changed at any time. ※ Do not fill in the symbol part.) ※Application number: ※Application date: 'α, 4 effect 1?&lt;: Classification: ΙΑμ (2 〇 〇 〇1) 1. Name of the invention: (Chinese/English) Gas sensor with diffusion microcavity and its manufacturing method/Gas Sensor with Diffuse Micro Cavity Structure and Method thereof. II. Applicant: (1 in total) Name or name · (Chinese / English) (signature) Industrial Technology Research Institute Representative / (Chinese / English) (signature) Zhang Jinfu / CHANq JIN_FU Residence or business address: ( Chinese/English) No.195, Section 4, Zhongxing Road, Zhudong Town, Hsinchu County / No.195, Sec.4, Chung Hsin Rd., Chu Tung Town, Hsin Chu Hsien, Taiwan, ROC Nationality: (Chinese/English) Republic of China/ ROC III. Inventor: (4 in total) Name··(Chinese/English) 1·Chen Yicheng/CHEN, I-CHERNG 2. Zhang Zhixiang/CHANQCHICH-SHANO 3. He Chaoren/HO, CHAO-JEC 4·Qiu Guo创/CHIU, KUO-CHUANG Nationality: (Chinese/English) 1~4·Republic of China/ROC 1 1325054 一一一_-一. 1讳/! The date of the change of the day is changed to the temperature of the Gongcai 13 is controlled to make it break within a certain temperature range. The technology is to set the heater on the surface of the sensing substrate, the temperature It is impossible to conduct evenly' and the heater needs additional addition to increase the cost. In particular, the heater is embedded in the interior of the sensing substrate 13 to achieve uniform temperature conduction during heating. Therefore, in the preferred embodiment of the present invention, the sensing substrate 13 is embedded in the sensing substrate 13 by embedding the conductive electrode and the heater 17 in a buried manner by using the characteristics of the laminated circuit. The heating temperature of the substrate 13 is measured to be uniform and the volume of the sensing substrate 13 can be lowered after being buried. In addition to the main control circuit, other required resistors are designed inside the sensing material 13 to achieve process simplification and reduce cost. The microcavity unit tl 12 includes a microcavity body 18 and a diffusion hole 151 disposed on the microcavity body 18. The microcavity 18 is used to form a microcavity ^01 to provide a stable operating temperature of the gas sensor 10 to prevent interference from ambient airflow. The microcavity body 18 is provided with 151, and the gas molecules entering the micro*cavity 18 are limited by the size of the pores of the diffusion hole 151. In the embodiment of the present invention, oxygen is used as the crucible. The bulk molecule 'when sensing oxygen' is required to have a diameter smaller than the core m to achieve the function of spontaneous diffusion sampling of oxygen. μ The microcavity unit of the gas sensor 10 is fabricated by a micro-electromechanical processing method of a CMOS/MEMS process to form a micro-cavity 18 of a glass, twin and its surface coating to form the micro, 兀12 . As shown in the first figure, it is a flow chart of the etching steps of the microelectromechanical processing of the microcavity. First, two diffusion holes 151 having a diameter of less than 20/m are formed on the microcavity body 18, so that the gas to be tested can flow through the diffusion holes 151 and achieve spontaneous gas diffusion. In the process of the microcavity unit, the micro-cavity is made by first defining the pattern size by semi-conducting = process and then making the isotropic (four) 9 04 丨月心日修正 replacement page 18 (4) smear yellow light After the process defines the pattern size, the anisotropy is performed: the diffusion hole 151. Wherein the isotropic sequence is wet etched instead of isotropic etch (anisotropic etch) with dry etch α 5 χ. Anisotropic etching can also be performed by one-sided etching or double etching. The gas, the sensing unit of the sensor 10 is manufactured by a doctor blade = technology! : J thick film powder such as zirconia or other oxygen ion conductor made of green embryos and laminated io to make a thickness of 5_3G &quot; m sensing substrate 13 . The sensing electrodes 13 and the lower surfaces 131 and 132 are provided with a plurality of sensing electrodes 15 connected to the external circuit, so that the material circuit (4) senses the magnitude of the current of the sensing 2 15 to convert the oxygen concentration in the air. . A plurality of conductive electrodes 16 and a plurality of heaters I are embedded in the sensing substrate 13 by co-firing or electromachining. Finally, the microcavity unit side sensing unit is joint-bonded into a bismuth-based ceramic hybrid element by a 1% pole bond or material co-melting point to form a gas sensor of the present diffusing microcavity unit. Therefore, the present invention can achieve the following effects: 2 It is difficult to interfere with the ambient airflow, and the reliability of the sensing gas is improved. = Functionally sensed thick film powder high-temperature process products are packaged in each other. 2. The microcavity structure 3 t ′ is produced in a low-temperature CM0S/MEMS process to achieve consistent reproducibility of gas diffusion sampling. 4 Provides a miniaturized and power-saving gas sensor with a microcavity. 5•, the heater can make the temperature conduction uniform, and the thickness of the thick film is reduced. • Microelectromechanical machining can be used for precision machining of microcavity volume and diffusion holes. Ceramic lamination sintering is used in the prior art. The volume and diffusion hole of the microcavity are easily deformed and difficult to control. Using the wafer level package, it is easy to mass-produce miniaturization 1325054 _一一一• ^^年年月24日修正定定页 [Simple description] The first picture shows the diffusion microcavity of the present invention A schematic diagram of the gas sensor of the unit. The second figure is a flow chart for fabricating a microcavity unit of a gas sensor with a diffusion microcavity unit according to the present invention. The third figure is a schematic diagram of the structure of a conventional diffused gas sensor. The fourth figure is a schematic structural view of a conventional micro-hole cover gas sensor. [Main component symbol description] • 10... Gas sensor 11 with diffusion microcavity unit... Sensing unit 12··· Microcavity unit 13... Sensing substrate 131... Upper surface 132... Lower surface 14... a sensing electrode 15...a second sensing electrode 16...a conducting electrode®17...a heater 18...a microcavity body 151...a diffusion hole 30...a diffused gas sensor 40...a micropore cover gas sensor 31, 41 ...sensing material layer 32, 42...sensing electrode 431···hole structure 43...microporous ceramic cover 12