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WO2021128636A1 - Capteur mems et dispositif électronique - Google Patents

Capteur mems et dispositif électronique Download PDF

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Publication number
WO2021128636A1
WO2021128636A1 PCT/CN2020/082539 CN2020082539W WO2021128636A1 WO 2021128636 A1 WO2021128636 A1 WO 2021128636A1 CN 2020082539 W CN2020082539 W CN 2020082539W WO 2021128636 A1 WO2021128636 A1 WO 2021128636A1
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WO
WIPO (PCT)
Prior art keywords
magnet
substrate
mems sensor
magnetoresistive device
axis
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.)
Ceased
Application number
PCT/CN2020/082539
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English (en)
Chinese (zh)
Inventor
邹泉波
冷群文
丁凯文
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Goertek Microelectronics Inc
Original Assignee
Goertek Microelectronics Inc
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 Goertek Microelectronics Inc filed Critical Goertek Microelectronics Inc
Publication of WO2021128636A1 publication Critical patent/WO2021128636A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
    • B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/04—Microphones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor

Definitions

  • the present invention belongs to the field of energy conversion technology. Specifically, the present invention relates to a MEMS sensor and an electronic device using the sensor.
  • CMOS complementary metal-oxide-semiconductor
  • CMOS complementary metal-oxide-semiconductor
  • Capacitor sensing structure In the structure of a microphone, it usually includes a substrate and a back plate and a diaphragm formed on the substrate. There is a gap between the back plate and the diaphragm, so that the back plate and the diaphragm together form a flat plate. Capacitor sensing structure.
  • the gap or the air flow resistance in the perforation caused by the air viscosity becomes the dominant factor of the MEMS microphone noise, which will limit the high signal-to-noise ratio performance of the microphone to a certain extent, and eventually lead to poor performance of the microphone.
  • a traditional magnetic sensor structure without a backplane can also be used to form sensors such as microphones.
  • the magnetic sensor and the magnet are respectively placed on two relatively moving planes, and the sound pressure will deform the diaphragm out of the plane, thereby changing the gap between the magnetic sensor and the magnet.
  • the sensor with this structure needs to accurately control the gap of the static position.
  • the positional relationship between the magnetic sensor and the magnet directly affects the detection accuracy of the magnetic sensor, and further affects the sensitivity of the sensor and the accuracy of converting sound into electrical signals.
  • the magnetic field strength of the magnet, the relative position of the magnetic sensor and the magnet, etc. will all have a significant impact on the sensitivity of the sensor, so the processing accuracy of the processing technology is relatively high.
  • An object of the present invention is to provide an improved MEMS sensor.
  • a MEMS sensor including:
  • a first substrate and a second substrate are distributed on a plane composed of the X-axis and the Y-axis, and the first substrate and the second substrate are configured to generate relative vibration along the Z-axis direction;
  • a magnet the magnetization direction of the magnet is in a plane formed by the X axis and the Y axis, the magnet is arranged on the first substrate, and the magnetic field strength of the magnet is greater than 8*10 5 amperes/m;
  • a magnetoresistive device the magnetization direction of the magnetoresistive device is in the Z-axis direction, and the magnetoresistive device is arranged on the second substrate;
  • the resistance value of the magnetoresistive device changes under the action of the magnetic field generated by the magnet.
  • the magnetoresistive device is configured to be manufactured by a pinning annealing process, in which a magnetic field in the Z-axis direction is applied to the magnetoresistive device.
  • the annealing temperature is 250°C-300°C.
  • the magnetic field strength of the magnet is greater than 8*10 6 amperes/meter.
  • the magnet is a thin film magnet, and the thickness of the magnet is greater than 0.2 micrometers.
  • the magnetoresistive device includes a pinned layer, a spacer layer, and a magnetically permeable layer, the spacer layer is disposed on the pinned layer, and the magnetically permeable layer is disposed on the spacer layer.
  • the material of the spacer layer is copper.
  • it further includes a dielectric layer, the dielectric layer is disposed on the second substrate, and the magnetoresistive device is disposed on the dielectric layer.
  • it further includes an adjustment structure, a gap is left between the adjustment structure and the first substrate and the magnet, and there is a height difference between the adjustment structure and the second substrate in the Z-axis direction;
  • the adjustment structure is configured to be able to pass in a signal so as to generate a force between the adjustment structure and the magnet;
  • the first substrate and the magnet are configured to be positionally shifted in the Z-axis direction under the force generated by the adjustment structure.
  • Another aspect of the present invention also provides an electronic device, which uses the above-mentioned MEMS sensor.
  • a technical effect of the present invention is that the magnet is magnetized in the XY plane, and the magnetoresistive device is magnetized in the Z-axis direction, which improves the space utilization rate.
  • Fig. 1 is a schematic diagram of the cooperation between a magnet and a magnetoresistive device of a MEMS sensor provided by the present invention
  • FIG. 2 is a schematic diagram of the side structure of the MEMS sensor provided by the present invention.
  • FIG. 3 is a schematic side view of another embodiment of the MEMS sensor provided by the present invention.
  • Fig. 4 is a schematic diagram of the cooperation between the adjustment structure of the MEMS sensor and the magnet provided by the present invention.
  • the present invention provides a MEMS sensor, which can be a MEMS pressure sensor, a MEMS gas sensor, a MEMS microphone, a MEMS temperature sensor, a MEMS humidity sensor, a MEMS displacement sensor, or other sensors well known to those skilled in the art.
  • a MEMS sensor when applied to a pressure sensor, the sensitive membrane is sensitive to external pressure, and changes in external pressure will drive the sensitive membrane to deform.
  • a driving rod can be set to connect with the sensitive membrane, and the sensitive membrane can be pushed through the driving rod to deform, which will not be listed here.
  • the present invention also provides an electronic device using the above MEMS sensor.
  • the electronic device may be a smart device known to those skilled in the art such as a mobile phone, a tablet computer, a smart bracelet, and smart glasses.
  • the MEMS sensor of the present invention adopts a coordinated sensing method of a magnet and a magnetoresistive device.
  • Fig. 1 shows the relative position and matching relationship of the magnet 1 and the magnetoresistive device 2 of the MEMS sensor of the present invention.
  • the magnet 1 is magnetized in a plane direction through a magnetization process, that is, magnetized in a plane formed by the X axis and the Y axis.
  • the magnetic pole direction of the magnet 1 is located in the plane formed by the X axis and the Y axis.
  • the magnetoresistive device 2 is arranged around the magnet 1, and its position relative to the magnet 1 is in the plane formed by the X axis and the Y axis.
  • the magnetoresistive device 2 is provided around the magnet 1 along the plane direction.
  • the magnetic field generated by the magnet 1 passes through the magnetoresistive device 2.
  • the magnetization direction of the magnetoresistive device is in the direction of the Z axis, for example, the magnetoresistive device is magnetized in the vertical direction. Through this magnetization process, the magnetoresistive device can respond to the change of the magnetic field in the Z-axis direction, and its resistance value will change, thereby generating a sensing signal.
  • the magnetoresistive device may be, for example, a GMR or TMR device.
  • the magnet 1 and the magnetoresistive device 2 are configured to produce a relative displacement in the Z-axis direction.
  • a Z-axis displacement is generated between the two, the magnetic field generated by the magnet 1 passes through the magnetic resistance.
  • the part of the device 2 will change, and the resistance of the magnetoresistive device 2 will change in response, thereby generating a sensing signal.
  • the MEMS sensor has a first substrate 10 and a second substrate 20 distributed on a plane composed of the X axis and the Y axis.
  • the magnet 1 is arranged on the first substrate 10
  • the magnetoresistive device 2 is arranged on the second substrate 20.
  • the first substrate 10 and the second substrate 20 are configured to be capable of relative movement and vibration along the Z-axis direction, and meet the required relative displacement sensing conditions between the magnet 1 and the magnetoresistive device 2.
  • the magnetic field strength of the magnet 1 used in the present invention is greater than 8*10 5 amperes/meter. Increasing the magnetic field strength of the magnet 1 can increase the resistance change of the magnetoresistive device 2 with respect to the change in the magnetic field when the magnet 1 and the magnetoresistive device 2 are relatively displaced. In this way, the responsiveness of the magnetoresistive device is increased, and the generated sensor signal is also stronger. Moreover, because the strength of the magnetic field is increased, even if the relative displacement between the magnet and the magnetoresistive device is small, the magnetoresistive device can respond to changes in the magnetic field, change the resistance value, and achieve the effect of improving the sensitivity of the MEMS sensor.
  • the magnetic field of the magnet can be enhanced to a certain extent.
  • the present invention adopts the technical characteristics of polarizing the magnet in the plane formed by the XY axis. Therefore, the thickness of the magnet can be appropriately increased in the Z axis direction, so that the magnetic field strength of the magnet is higher than 8*10 5A /m. Further achieve higher magnetic field strength.
  • the MEMS sensor since the magnet and the magnetoresistive device need to produce relative displacement in the Z-axis direction, the MEMS sensor itself will leave sufficient space in the Z-axis direction for the relative displacement of the magnet and the magnetoresistive device in the Z-axis direction. In this case, increasing the thickness of the magnet in the Z-axis direction will not affect the space occupied by the entire MEMS sensor in the Z-axis direction.
  • the technical solution of the present invention can effectively increase the magnetic field strength of the magnet without increasing the overall volume and occupied space of the MEMS sensor, thereby improving the responsiveness, sensitivity, and signal strength of the MEMS sensor. Comprehensively improve the performance of MEMS sensors.
  • the technical solution of the present invention stably controls the magnetization direction of the magnet and the magnetoresistive device, thereby being able to increase the thickness and volume of the magnet without occupying more lateral space, thereby not affecting the overall size of the MEMS sensor .
  • the magnetoresistive device can be manufactured by a pinning annealing process.
  • the magnetization direction of the magnetoresistive device can be effectively and stably fixed in a specific direction, thereby meeting the requirements for matching the magnetization direction between the magnetoresistive device and the magnet, and improving the magnetic field generated by the magnetoresistive device against the magnet. Response sensitivity to changes in relative displacement.
  • the magnetoresistive device is placed in a preset annealing temperature environment.
  • the annealing temperature may be in the range of 150°C to 400°C.
  • the magnetoresistive device is heated to the annealing temperature in the form of heat treatment, and a magnetic field in a specific direction is applied in the environment where the magnetoresistive device is located.
  • a magnetic field in a specific direction is applied in the environment where the magnetoresistive device is located.
  • the magnetoresistive device will be magnetized by the magnetic field, and its magnetization direction is consistent with the direction of the magnetic field applied to the environment.
  • the magnetoresistive device is kept in the above-mentioned magnetic field and temperature environment for a certain period of time, and then gradually cooled.
  • the above-mentioned ambient magnetic field can be continuously maintained until it is cooled to room temperature.
  • the magnetization degree and direction of the magnetoresistive device will be fixed. Even if the external magnetic field and ambient temperature are removed, the magnetization state of the magnetoresistive device will not change.
  • an environmental magnetic field distributed along the Z-axis is applied during the pinning annealing process, so that the magnetoresistive device is magnetized along the Z-axis to meet the requirements of the magnetization in the XY-axis plane.
  • the return temperature of the pinning annealing process is 250°C-300°C. Returning goods at medium temperature within this temperature range can make the magnetoresistive device fully magnetized on the one hand; on the other hand, it can try to avoid the structural performance of the magnetoresistive device from changing due to high temperature.
  • the magnetic field strength of the magnet is greater than 8*10 6 amperes/meter.
  • the magnetic field strength of the magnet can be effectively increased.
  • the increase of the magnetic field strength can make the magnetoresistive device make a more obvious resistance change response to the slight relative displacement, and improve the sensitivity of the MEMS sensor.
  • the magnet is formed on the first substrate by using a thin film magnet.
  • the thin film magnet may be formed by means of vapor deposition or the like.
  • the thickness of the magnet may be greater than 0.2 microns, so that the magnetization in the XY plane is stronger, and the generated magnetic field has a higher magnetic field strength.
  • the thickness of the magnet is greater than 0.5 microns.
  • the first substrate, the second substrate and other structures themselves have a thickness greater than 0.5 micrometers.
  • the thickness of the first substrate and the second substrate can be set between 0.5 ⁇ m and 2.5 ⁇ m.
  • the MEMS sensor as a whole needs to be set aside in the Z-axis direction to match the size of the first and second substrates. Matching space for both displacements. In this case, increasing the thickness of the magnet in the Z-axis direction to 0.5 microns will not occupy too much space in the Z-axis direction, and will not affect the overall reserved space and size of the MEMS sensor.
  • the magnetoresistive device 2 may include a pinning layer 21, a spacer layer 22 and a magnetic conductive layer 23.
  • the spacer layer 22 is disposed on the pinning layer 21, and the magnetic conductive layer 23 is disposed on the spacer layer 22.
  • the pinned layer 21 serves as the main magnetized structure in the magnetoresistive device 2 and is used to induce the magnetic field of the magnet 1.
  • the magnetically permeable layer 23 is made of a magnetically permeable material, which is used to guide the magnetic field generated by the magnet 1 to the pinned layer 21 to improve the strength of the magnetic field passing through the pinned layer 21.
  • the spacer layer 22 is used to carry the magnetic conductive layer 23.
  • the spacer layer 22 is made of copper, which provides good structural stability and electrical performance.
  • FIG. 2 shows an embodiment of the present invention.
  • the MEMS sensor may further include a dielectric layer 25.
  • the dielectric layer 25 is disposed on the second substrate 20.
  • the magnetoresistive device 2 is disposed on the dielectric layer 25.
  • the dielectric layer 25 can provide protection for the magnetoresistive device 2.
  • the thickness of the dielectric layer 25 affects the height position of the magnetoresistive device 2.
  • the thickness of the dielectric layer 25 can be adjusted to realize the process of aligning the magnetoresistive device 2 and the magnet 1 on the XY axis formation plane.
  • a conductor layer 24 and a protective cover 3 may also be formed on the dielectric layer 25, and the conductor layer 24 is configured to form an electrical connection with the magnetoresistive device 2 to form a sensor circuit.
  • the protective cover 3 may be arranged on the magnetoresistive device 2 and the conductor layer 24 to provide protection.
  • the magnet 1 may be provided on the first substrate 10. A gap is left between the first substrate 10 and the second substrate 20 so that they can be displaced relative to each other. A protective cover 3 may also be formed on the magnet 1.
  • FIG. 3 shows another embodiment of the present invention.
  • the first substrate 10 forms a cantilever structure, and the magnet 1 is located at a position farther from the fixed area of the cantilever structure. In this way, the first substrate 10 and the magnet 1 carried thereon can be displaced in the Z direction relative to the fixed second substrate 20 and the magnetoresistive device 2.
  • a sound-receiving component such as a diaphragm may be connected to the second substrate. When there is sound and air vibration around, the second substrate will vibrate accordingly, and then drive the magnet to vibrate.
  • the magnetoresistive device 2 can respond when the magnet vibrates, and its resistance value changes.
  • the MEMS sensor may further include an adjustment mechanism.
  • the adjustment mechanism is separately arranged in the MEMS sensor, and a gap is left between the adjustment structure 4 and the first substrate 10 and the magnet 1.
  • the adjustment structure 4 can be fed with a signal, so that electrostatic or electromagnetic force is generated between it and the magnet 1 and the first substrate 10.
  • the force generated by the adjustment structure 4 can shift the positions of the magnet 1 and the first substrate 10.
  • the adjusting structure 4 is used to adjust the height of the magnet 1 and the first substrate 10 in the Z-axis direction, so that the magnet 1 can be aligned with the magnetoresistive device 2 in the Z-axis direction.
  • the MEMS sensor equipped with the adjustment structure 4 can make the positioning of the magnetoresistive device 2 and the magnet 1 more accurate, and improve the sensing accuracy. Since there is a height difference between the adjustment structure 4 and the second substrate 20 in the Z-axis direction, the adjustment structure 4 can align the magnet with the magnetoresistive device 2 by generating a suitable force. It will not happen that the component in the Z-axis direction of the traction force generated between the adjusting structure 4 and the magnet is not enough to pull the magnet to a position that is aligned with the magnetoresistive device 2 in the Z

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Micromachines (AREA)

Abstract

Un capteur MEMS et un dispositif électronique sont divulgués. Le capteur MEMS comprend : un premier substrat et un second substrat distribués dans un plan composé d'un axe X et d'un axe Y, le premier substrat et le second substrat étant conçus pour pouvoir générer une vibration relative dans une direction d'axe Z ; un aimant, la direction de magnétisation de l'aimant étant dans le plan formé par l'axe X et l'axe Y, l'aimant étant disposé sur le premier substrat, et la force de champ magnétique de l'aimant étant supérieure à 8*105 ampère/mètre ; et un appareil de résistance magnétique, la direction de magnétisation de l'appareil de résistance magnétique étant dans la direction de l'axe Z, et l'appareil de résistance magnétique étant disposé sur le second substrat. Si une vibration relative est générée entre le premier substrat et le second substrat, la valeur de résistance de l'appareil de résistance magnétique change sous l'action du champ magnétique généré par l'aimant.
PCT/CN2020/082539 2019-12-26 2020-03-31 Capteur mems et dispositif électronique Ceased WO2021128636A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201922418542.1 2019-12-26
CN201922418542.1U CN211089970U (zh) 2019-12-26 2019-12-26 一种mems传感器和电子设备

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WO2021128636A1 true WO2021128636A1 (fr) 2021-07-01

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WO (1) WO2021128636A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112014778B (zh) * 2020-08-24 2023-11-07 歌尔微电子有限公司 微机电系统磁阻传感器、传感器单体及电子设备
CN113613152B (zh) * 2021-07-30 2023-06-30 歌尔微电子股份有限公司 微机电系统麦克风、麦克风单体及电子设备

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7126327B1 (en) * 2005-07-22 2006-10-24 Honeywell International Inc. Asymmetrical AMR wheatstone bridge layout for position sensor
CN109218870A (zh) * 2018-08-06 2019-01-15 歌尔股份有限公司 一种麦克风
CN109275080A (zh) * 2018-08-06 2019-01-25 歌尔股份有限公司 一种传感器
CN109941956A (zh) * 2019-02-25 2019-06-28 歌尔股份有限公司 Mems传感器及电子设备

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7126327B1 (en) * 2005-07-22 2006-10-24 Honeywell International Inc. Asymmetrical AMR wheatstone bridge layout for position sensor
CN109218870A (zh) * 2018-08-06 2019-01-15 歌尔股份有限公司 一种麦克风
CN109275080A (zh) * 2018-08-06 2019-01-25 歌尔股份有限公司 一种传感器
CN109941956A (zh) * 2019-02-25 2019-06-28 歌尔股份有限公司 Mems传感器及电子设备

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