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WO2014185771A2 - Capteur d'humidité capacitif - Google Patents

Capteur d'humidité capacitif Download PDF

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Publication number
WO2014185771A2
WO2014185771A2 PCT/MY2014/000093 MY2014000093W WO2014185771A2 WO 2014185771 A2 WO2014185771 A2 WO 2014185771A2 MY 2014000093 W MY2014000093 W MY 2014000093W WO 2014185771 A2 WO2014185771 A2 WO 2014185771A2
Authority
WO
WIPO (PCT)
Prior art keywords
humidity sensor
capacitive humidity
ground plane
layer
semiconductor substrate
Prior art date
Application number
PCT/MY2014/000093
Other languages
English (en)
Other versions
WO2014185771A3 (fr
Inventor
Lee WAI YEE
Nabipoor Mohsen
Daniel Bien CHIA SHENG
Sulaiman Suraya
Original Assignee
Mimos Berhad
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Mimos Berhad filed Critical Mimos Berhad
Publication of WO2014185771A2 publication Critical patent/WO2014185771A2/fr
Publication of WO2014185771A3 publication Critical patent/WO2014185771A3/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
    • G01N27/223—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance for determining moisture content, e.g. humidity

Definitions

  • the present invention relates to a humidity sensor and its method of fabricating and its method for preparing.
  • a humidity sensor also called ahygrometer, measures and regularly reports
  • Humidity sensors can also be used in cars, office and industrialHVAC systems, and in meteorology stations to report and predict weather.
  • a humidity sensor senses relative humidity. This means that it measures both air temperature and moisture. Relative humidity, expressed as a percent, is the ratio of actual moisture in the air to the highest amount of moisture air at that temperature can hold. The warmer the air is, the more moisture it can hold, so relative humidity changes with fluctuations in temperature.
  • the most common type of humidity sensor uses what is called 'capacitive measurement.' This system relies on electrical capacitance, or the ability of two nearby electrical conductors to create an electrical field between them.
  • the sensor itself is composed of two metal plates with a non-conductive polymer film between them. The film collects moisture from the air, and the moisture causes minute changes in the voltage between the two plates. The changes in voltage are converted into digital readings showing the amount of moisture in the air.
  • interdigitated capacitive humidity sensors comprises sensing membranes only on the top side of the electrodes, like in WO2012067488, which relates to a sensor for determining humidity.
  • a humidity sensor comprises of a substrate; a bottom membrane positioned above the substrate and a top membrane positioned abovethe bottom membrane forming a dielectric layer; and a plurality of inter-digitated electrodes with changing capacitance in accordance to change in humidity detected by the dielectric layer embedded to the top membrane wherein a plurality of trenches areembedded to the bottom membrane or to the substrate thereby increasing area of exposure to humidity.
  • the prior art also relates to a method for fabricating a humidi- tysensor.
  • the present invention provides aca- pacitive humidity sensor ( 100) comprising:a semiconductor substrate ( 101 ); an insulating layer (103) rests on the semiconductor substrate ( 101 ); a sensing membrane ( 105); a plurality of interdigitated electrodes ( 107); and a plurality of electrode contacts (109); characterised in that the interdigitated electrodes ( 107) are sandwiched by the sensing membrane (105) to provide optimal utilisation of fringing field effect.
  • the above provision is advantageous as it increases the performance of the sensor.
  • the present invention provides acapacitive humidity sensor (100) comprising: a semiconductor substrate (101 ); an insulating layer (103) rests on the semiconductor substrate (101 ); a sensing membrane (105); a plurality of interdigitated electrodes (107); and a plurality of electrode contacts (109); characterised in that the capacitive humidity sensor (100) further comprising ground plane connections (1 1 1) to eliminate stray capacitance.
  • acapacitive humidity sensor comprising: a semiconductor substrate (101 ); an insulating layer (103) rests on the semiconductor substrate (101 ); a sensing membrane (105); a plurality of interdigitated electrodes (107); and a plurality of electrode contacts (109); characterised in that the capacitive humidity sensor (100) further comprising ground plane connections (1 1 1) to eliminate stray capacitance.
  • FIG. 13 Figure lillustrates one embodiment of acapacitive humidity sensor device of the present invention.
  • Figure 2 illustrates the present inventionwith (a) grounding pads only; and (b) with shielding wire surrounding the interdigitated electrodes.
  • Figure 3 illustrates a flowchart of a method for preparing the present invention.
  • FIG. 16 Figure illustrates sequential diagrams of preparing the present invention.
  • Figure 5 illustratesa method of packaging a capacitive humidity sensor on a printed circuit board (PCB) of the present invention.
  • the present invention relates to acapacitive humidity sensor (100)
  • the capacitive humidity sensor ( 100) further comprising ground plane connections ( 1 1 1 ) to maximally reduce stray capacitance.
  • the present invention havingthe interdigitated electrodes ( 107) are sandwiched between two sensing membranes, typically of polyimide material.
  • the present invention also having the electrodes contacts (109) connected to a ground plane (1 1 1a) formed on the underlying doped semiconductor substrate ( 101 ) with an aim to eliminate stray capacitances.
  • the ground plane connections ( 1 1 1 ) are formed on the same side as the interdigitated electrodes ( 107) and its electrode contacts ( 109). This eases electrical connection by wire bonding during device packaging where back ground contact is not required.
  • connection to the ground plane ( 1 1 1 a) can be of only electrical ground contact pads ( Figure 2a) or with a shielding wire ( 1 13) surrounding the interdigitated electrodes ( 107) ( Figure 2b).
  • the shielding wire ( 1 13) helps to isolate the present invention from stray capacitance and electrical noise from the other devices. This is important when an array of sensors is deployed for a certain monitoring application.
  • the present invention operates based on fringing electric field effects (FEF) with an output of electrical capacitance.
  • FEF fringing electric field effects
  • With interdigitated based devices there is fringing field on both side of the electrode, hence by having sensing membranes ( 105) on both sides of the interdigitated structures, allows full utilisation of the fringing field of the capacitor device. Hence the sensitivity and performance of the device would be significantly improved.
  • the sensing membranes (105) would absorb moisture from the air, changing both their material dielectric permittivity resulting in a change in the overall device capacitance. Dielectric permittivity of both the membrane would increase with increasing moisture/humidity level and vice versa for decreasing moisture/permittivity.
  • a method for preparing a capacitive humidity sensor comprising: doping of silicon substrate n- or p- type dopants to form the silicon ground plane layer (201); depositing and patterning an insulating layer comprising silicon oxide or silicon nitride on top of the silicon substrate surface (203); depositing and patterning a first membrane layer on top of the insulating layer (205); and depositing and etching a conductive layer on top of the bottom sensing membrane (207); characterized in that depositing and patterning a second membrane layer on top of the interdigitated electrodes (209).
  • the method starts with doping of silicon substrate (101 ) to form the ground plane layer ( Figure 4a).
  • Silicon can be doped with n- or p- type materials by thermal diffusion or ion implantation.
  • Then is followed by depositing and patterning an insulating layer ( 103) on the silicon substrate surface to act as an electrical isolation layer between the conductive electrodes and the substrate (101 ) ( Figure 4b).
  • the insulating layer ( 103) can be of silicon oxide or silicon nitride and is patterned to allow electrical connection to the ground plane. It continues with forming the bottom polyimide sensing membrane ( 105) by depositing and patterning a first polyimide layer on top of the insulating layer (103) ( Figure 4c).
  • the sensing membrane (105) is used to capture the fringing electric field beneath the interdigitated electrodes and is patterned to expose ground plane connections.
  • Next step is forming the interdigitated capacitive electrodes ( 107) and connections to the silicon ground plane ( 1 1 la) by depositing and etching a conductive layer on top of the bottom sensing membrane ( Figure 4d).
  • the conduction layer is of material not limited to aluminium, tungsten, gold or platinum.
  • the steps are ended with the step of forming the top polyimide sensing membrane (105) by depositing and patterning a second polyimide layer on top of the conductive electrodes ( Figure 4e).
  • the polyimide membrane is used to capture the fringing electric field on top of the interdigitated electrodes (107) and is patterned to expose ground plane connections ( 1 1 1 ) and contact pads to the interdigitated electrodes ( 107).
  • a method of packaging a capacitive humidity sensor on a printed circuit board comprising:dicing a semiconductor substrate which contains the capacitive humidity sensors into dies (301 );attaching the capacitive humidity sensor dies to the die pad area predefined on the said PCB (303);wire bonding the contact pads of the capacitive humidity sensor to metal leads prefabricated on the said PCB (305); and encapsulating the wire bonds with a protective epoxy (307).
  • a protective epoxy (307).

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

La présente invention concerne un capteur d'humidité capacitif (100) comprenant un substrat semi-conducteur (101), une couche isolante (103) reposant sur le substrat semi-conducteur (101), une membrane sensible (105), une pluralité d'électrodes interdigitées (107) et une pluralité de contacts d'électrodes (109). L'invention est caractérisée en ce que des connexions de plan de masse (111) et les électrodes interdigitées (107) sont prises en sandwich par la membrane sensible (105). Les connexions de plan de masse (111) et la membrane sensible (105) les prenant en sandwich sont conçues pour éliminer la capacité parasite et permettre une utilisation optimale de l'effet du champ de bord respectivement.
PCT/MY2014/000093 2013-05-17 2014-05-02 Capteur d'humidité capacitif WO2014185771A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
MYPI2013001818 2013-05-17
MYPI2013001818 2013-05-17

Publications (2)

Publication Number Publication Date
WO2014185771A2 true WO2014185771A2 (fr) 2014-11-20
WO2014185771A3 WO2014185771A3 (fr) 2015-04-30

Family

ID=51300797

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/MY2014/000093 WO2014185771A2 (fr) 2013-05-17 2014-05-02 Capteur d'humidité capacitif

Country Status (1)

Country Link
WO (1) WO2014185771A2 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104634833A (zh) * 2015-02-28 2015-05-20 苏州工业园区纳米产业技术研究院有限公司 Mems电容式相对湿度传感器及其制备方法
CN108287185A (zh) * 2018-01-09 2018-07-17 南京信息工程大学 一种探空湿度传感器、制备方法、探空湿度测量系统及测量方法
WO2018153532A1 (fr) * 2017-02-21 2018-08-30 E+E Elektronik Ges.M.B.H Dispositif de capteur d'humidité
CN109781799A (zh) * 2018-12-29 2019-05-21 西安交通大学 一种电容型的蚕丝蛋白湿度传感器及其制备方法
CN109911839A (zh) * 2017-12-12 2019-06-21 中国科学院半导体研究所 能抑制光噪声的微电极、采用其的电路及其制备方法
US20210109053A1 (en) * 2018-07-04 2021-04-15 Murata Manufacturing Co., Ltd. Humidity sensor and rfid tag including the same
CN114018991A (zh) * 2021-09-18 2022-02-08 中国科学院微电子研究所 一种湿度传感器及其制备方法

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012067488A1 (fr) 2010-11-15 2012-05-24 Mimos Berhad Capteur d'humidité et procédé pour sa fabrication

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7461560B2 (en) * 2005-03-28 2008-12-09 Microstrain, Inc. Strain gauge with moisture barrier and self-testing circuit
EP1686026A1 (fr) * 2005-01-31 2006-08-02 IEE INTERNATIONAL ELECTRONICS & ENGINEERING S.A. Capteur capacitif différentiel de pluie
MY164505A (en) * 2007-11-23 2017-12-29 Mimos Berhad Capacitive sensor

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012067488A1 (fr) 2010-11-15 2012-05-24 Mimos Berhad Capteur d'humidité et procédé pour sa fabrication

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104634833A (zh) * 2015-02-28 2015-05-20 苏州工业园区纳米产业技术研究院有限公司 Mems电容式相对湿度传感器及其制备方法
CN104634833B (zh) * 2015-02-28 2017-09-26 苏州工业园区纳米产业技术研究院有限公司 Mems电容式相对湿度传感器及其制备方法
WO2018153532A1 (fr) * 2017-02-21 2018-08-30 E+E Elektronik Ges.M.B.H Dispositif de capteur d'humidité
EP3364181B1 (fr) * 2017-02-21 2019-04-10 E+E Elektronik Ges.M.B.H. Système de capteur d'humidité avec une protection esd
CN109911839A (zh) * 2017-12-12 2019-06-21 中国科学院半导体研究所 能抑制光噪声的微电极、采用其的电路及其制备方法
CN109911839B (zh) * 2017-12-12 2023-10-13 中国科学院半导体研究所 能抑制光噪声的微电极、采用其的电路及其制备方法
CN108287185A (zh) * 2018-01-09 2018-07-17 南京信息工程大学 一种探空湿度传感器、制备方法、探空湿度测量系统及测量方法
CN108287185B (zh) * 2018-01-09 2024-01-12 南京信息工程大学 一种探空湿度传感器、制备方法、探空湿度测量系统及测量方法
US20210109053A1 (en) * 2018-07-04 2021-04-15 Murata Manufacturing Co., Ltd. Humidity sensor and rfid tag including the same
US11913896B2 (en) * 2018-07-04 2024-02-27 Murata Manufacturing Co., Ltd. Humidity sensor and RFID tag including the same
CN109781799A (zh) * 2018-12-29 2019-05-21 西安交通大学 一种电容型的蚕丝蛋白湿度传感器及其制备方法
CN114018991A (zh) * 2021-09-18 2022-02-08 中国科学院微电子研究所 一种湿度传感器及其制备方法

Also Published As

Publication number Publication date
WO2014185771A3 (fr) 2015-04-30

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