WO2020022078A1 - 圧力センサ及び圧力センサの製造方法 - Google Patents

圧力センサ及び圧力センサの製造方法 Download PDF

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Publication number
WO2020022078A1
WO2020022078A1 PCT/JP2019/027456 JP2019027456W WO2020022078A1 WO 2020022078 A1 WO2020022078 A1 WO 2020022078A1 JP 2019027456 W JP2019027456 W JP 2019027456W WO 2020022078 A1 WO2020022078 A1 WO 2020022078A1
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Prior art keywords
pressure
individual
pressure sensor
insulating film
insulating base
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PCT/JP2019/027456
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English (en)
French (fr)
Japanese (ja)
Inventor
秀明 灘
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Ｎｉｓｓｈａ株式会社
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Publication of WO2020022078A1 publication Critical patent/WO2020022078A1/ja

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/84—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by variation of applied mechanical force, e.g. of pressure

Definitions

  • the present invention relates to a pressure sensor and a method for manufacturing the same, and more particularly, to a pressure sensor having a large number of independent pressure-sensitive elements and thin-film transistors corresponding to the pressure sensors and a method for manufacturing the same.
  • a pressure sensor As a pressure sensor, a combination of a plurality of thin film transistors with a pressure-sensitive resin is known (for example, see Patent Document 1).
  • the pressure-sensitive resin is obtained by dispersing conductive particles in an insulating resin such as silicone rubber.
  • an insulating resin such as silicone rubber.
  • the conductive particles contact each other in the insulating resin, so that the resistance value decreases. Thereby, the pressure applied to the pressure-sensitive resin can be detected.
  • Many thin film transistors are arranged in a matrix and function as switches. As a result, it is possible to speed up the pressure detection, increase the resolution, and reduce the power consumption.
  • a pressure sensor in which a pressure-sensitive layer is formed for each individual electrode has been proposed. These pressure-sensitive layers are arranged to face the common electrode in the pressing direction. In this case, a change in resistance caused by a change in the contact area of the pressure-sensitive layer is detected.
  • the pressure sensor has an upper electrode member and a lower electrode member. An air space is secured between the two.
  • the upper electrode member has a base film and a common electrode.
  • the lower electrode member includes a base film, a plurality of TFTs formed on the base film, and an insulating film having via-processed portions (via holes and conductive filling portions) formed on the base film. , Via-processed portions, and a plurality of pressure-sensitive layers formed on the individual electrodes.
  • the TFT when the insulating film is thin, the TFT cannot withstand the impact when pressed. That is, the reliability of the pressure sensor is low. Conversely, when the insulating film is thick, the via hole extends vertically and elongated, and it becomes difficult to fill the via hole with a conductive material.
  • An object of the present invention is to improve the reliability of a pressure sensor with respect to stress in a pressure sensor having a plurality of electrodes arranged with a gap therebetween.
  • a pressure sensor includes a first insulating base, a common electrode, a second insulating base, a plurality of thin film transistors, a plurality of individual electrodes, an insulating film, and a plurality of pressure-sensitive layers. , Is provided.
  • the common electrode extends over the main surface of the first insulating base.
  • the second insulating base is arranged to face the main surface of the first insulating base.
  • the plurality of thin film transistors are provided on the main surface of the second insulating base material on the first insulating base material side so as to face the common electrode.
  • the plurality of individual electrodes are provided on the main surface of the plurality of thin film transistors on the first insulating base material side, and one is connected to one or two or more adjacent thin film transistors.
  • the insulating film is provided on the main surfaces of the plurality of thin film transistors and has a plurality of openings exposing the plurality of individual electrodes. “Exposing a plurality of individual electrodes” means that a plurality of individual electrodes are not covered with an insulating film.
  • the plurality of pressure-sensitive layers are provided in the plurality of openings, and extend from the plurality of openings toward the first insulating base material.
  • the plurality of pressure-sensitive layers are formed in the plurality of openings formed in the insulating film. Therefore, it is unnecessary to form a via hole in the insulating film and to fill the conductive material. Therefore, the thickness of the insulating film can be increased, and as a result, the reliability of the pressure sensor against stress increases.
  • the diameter of the opening may be in the range of 0.3 to 1.0 mm.
  • the thickness of the insulating film may be in the range of 3 to 10 ⁇ m. In this pressure sensor, in the above range, the shock resistance to the TFT when pressed is improved.
  • the edge of the opening may be located 20 ⁇ m to 300 ⁇ m radially outward from the outer peripheral edge of the pressure-sensitive layer. If it is less than 20 ⁇ m, the pressure-sensitive layer may run on the insulating film and the sensitivity may vary. If it exceeds 300 ⁇ m, a portion where the thin film transistor cannot be protected occurs, and the reliability is reduced.
  • the edge of the opening is preferably located at a position of 20 to 35 ⁇ m radially outward from the outer peripheral edge of the pressure-sensitive layer. In this pressure sensor, the variation in the shape of the inner wall of the opening is small, so that the electrodes can be reliably exposed.
  • the insulating film may be made of a photoresist.
  • the opening is formed by photolithography, the dimensional accuracy of the opening is improved. That is, the variation in the opening size of the opening is reduced, and the resistance value between the individual electrode and the pressure-sensitive layer is stabilized. As a result, variations in the sensitivity of the plurality of sensors including the individual electrodes and the pressure-sensitive layer are reduced.
  • the resistance value between the individual electrode and the pressure-sensitive layer increases because the insulating film covers the individual electrode.
  • the pressure-sensitive layer overlaps the upper surface of the insulating film, the height of the pressure-sensitive layer changes, so that the sensitivity varies.
  • the photoresist may be, for example, a dry film type.
  • DFR Deposition Film Resist
  • the pressure sensor may further include a plurality of spacers.
  • the plurality of spacers may be arranged between the plurality of individual electrodes in a plan view on the surface of the insulating film on the first insulating base material side, and may face the common electrode.
  • variation in sensitivity can be reduced.
  • the pressure-sensitive layer is formed in the opening, and the spacer is formed on the surface of the insulating film on the first insulating base material side. And the height of the spacer can be made different. That is, a gap can be secured between the pressure-sensitive layer and the common electrode.
  • the diameter of the plurality of spacers is smaller than the diameter of the plurality of pressure-sensitive layers, so that the height of the plurality of spacers may be smaller than the height of the plurality of pressure-sensitive layers. Therefore, the total height of the spacer and the insulating film does not become too high, that is, the gap between the pressure-sensitive layer and the upper electrode member can be kept small. As a result, the sensitivity at low pressure is improved.
  • the diameter of each of the plurality of spacers may be less than 0.3 mm.
  • a method for manufacturing a pressure sensor includes the following steps. ⁇ Step of forming a common electrode on the main surface of the first insulating base material ⁇ Step of forming a plurality of thin film transistors on the main surface of the second insulating base material ⁇ Corresponding to one or two or more adjacent thin film transistors Forming a plurality of individual electrodes facing the common electrode on the first insulating substrate-side main surface of the plurality of thin film transistors.
  • the plurality of pressure-sensitive layers are formed in the plurality of openings formed in the insulating film. Therefore, it is not necessary to form a via hole and fill a conductive material in the insulating film. As a result, the thickness of the insulating film can be increased, and as a result, the reliability of the pressure sensor against stress is increased.
  • the step of forming the insulating film may use photolithography.
  • photolithography since photolithography is used, variation in the size of the opening can be more easily controlled than in the case of forming the opening by printing. As a result, the resistance value between the individual electrode and the pressure-sensitive layer is stabilized. That is, variations among the sensors are reduced.
  • the area of the opening must be set to be large in consideration of a margin. However, if the opening is widened, durability decreases. Conversely, if the opening is narrow, the pressure sensitive layer will be placed outside the opening, thereby changing the sensitivity of the sensor.
  • the method for manufacturing a pressure sensor may further include a step of forming a plurality of spacers facing the common electrode between the plurality of individual electrodes in plan view on the surface of the insulating film on the first insulating base material side.
  • the step of forming the pressure-sensitive layer and the step of forming the spacer may be performed simultaneously by a printing method. In this method of manufacturing a pressure sensor, productivity is improved. In addition, the displacement between the pressure-sensitive layer and the spacer is eliminated, so that the sensitivity becomes accurate.
  • the reliability of the pressure sensor with respect to the stress of the pressure sensor is improved in a pressure sensor having a plurality of electrodes arranged with a gap therebetween.
  • FIG. 2 is a schematic cross-sectional view of the pressure sensor according to the first embodiment.
  • FIG. 3 is a schematic plan view of a lower electrode member of the pressure sensor.
  • FIG. 3 is a partially enlarged view of FIG. 2 and is a schematic plan view showing a planar positional relationship between an individual electrode and an individual spacer.
  • FIG. 3 is an equivalent circuit diagram of the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic sectional view of a pressure sensor according to a second embodiment.
  • FIG. 4 is a schematic plan view showing a planar positional relationship between an individual electrode and an individual spacer.
  • FIG. 9 is a schematic sectional view of a pressure sensor according to a third embodiment.
  • FIG. 4 is a schematic plan view showing a planar positional relationship between an individual electrode and an individual spacer.
  • FIG. 14 is a schematic sectional view of a pressure sensor according to a fourth embodiment.
  • FIG. 14 is a schematic sectional view of a pressure sensor according to a fifth embodiment.
  • 5 is a graph showing a change in pressure-sensitive layer thickness with respect to the pressure-sensitive layer size.
  • FIG. 14 is a schematic sectional view of a pressure sensor according to a sixth embodiment.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 9 is a schematic sectional view of a pressure sensor according to a third embodiment.
  • FIG. 4 is a schematic plan view showing a planar positional relationship between an individual electrode and an individual
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing the pressure sensor.
  • FIG. 7 is a schematic sectional view of a pressure sensor according to another embodiment.
  • FIG. 7 is a schematic sectional view of a pressure sensor according to another embodiment.
  • FIG. 1 is a schematic sectional view of the pressure sensor according to the first embodiment.
  • FIG. 2 is a schematic plan view of the lower electrode member of the pressure sensor.
  • FIG. 3 is a partially enlarged view of FIG. 2 and is a schematic plan view showing a planar positional relationship between an individual electrode and an individual spacer.
  • the pressure sensor 1 is a device that detects a pressing position and a pressing force when a pressing force acts.
  • the pressure sensor 1 is employed in, for example, a touch panel of a smartphone, a tablet PC, or a notebook PC.
  • the pressure sensor 1 has an upper electrode member 3.
  • the upper electrode member 3 is a planar member on which a pressing force acts.
  • the upper electrode member 3 is shared with an insulating film 7 (an example of a first insulating base material) and a common electrode 9 formed on the entire lower surface (an example of a main surface), that is, over the entire surface or by patterning. And a common pressure-sensitive layer 11 formed on the lower surface of the electrode 9.
  • the pressure sensor 1 has the lower electrode member 5.
  • the lower electrode member 5 is a planar member disposed below the upper electrode member 3.
  • the lower electrode member 5 has, for example, a rectangular insulating film 15 (an example of a second insulating base material).
  • the pressure sensor 1 has a plurality of thin film transistors 30 (hereinafter, referred to as “TFT 30”).
  • the plurality of TFTs 30 are provided on the main surface of the insulating film 7 of the insulating film 15 so as to face the common electrode 9.
  • the TFT 30 has a source electrode 17, a drain electrode 19, and a gate electrode 21, as shown in FIGS.
  • the TFT 30 is a top gate type.
  • the material forming the gate electrode, the source electrode, and the drain electrode is not particularly limited.
  • the source electrode 17 and the drain electrode 19 are formed on the upper surface of the insulating film 15.
  • the TFT 30 has an organic semiconductor 23 formed between the source electrode 17 and the drain electrode 19.
  • a known material such as silicon, an oxide semiconductor, or an organic semiconductor can be used.
  • the TFT 30 has a first insulating film 25 formed so as to cover the source electrode 17, the drain electrode 19 and the organic semiconductor 23.
  • the drain electrode 19 is connected to the individual electrode 31 as described later.
  • the gate electrode 21 is formed above the organic semiconductor 23 on the upper surface of the first insulating film 25.
  • a conductive portion 29 extending from the TFT 30 is formed in the first insulating film 25. The conductive portion 29 is connected to the individual electrode 31 described above.
  • the lower electrode member 5 has a plurality of individual electrodes 31.
  • the individual electrodes are also called pixel electrodes.
  • the plurality of individual electrodes 31 are provided on the main surface of the plurality of TFTs on the insulating film 7 side, and one is connected to one or two or more adjacent TFTs 30. More specifically, the individual electrode 31 is formed on the bottom surface of the opening 27A and is connected to the conductive part 29.
  • the lower electrode member 5 has a second insulating film 27 (an example of an insulating film).
  • the second insulating film 27 is provided on the main surfaces of the plurality of TFTs 30, and specifically, is provided on the first insulating film 25 on the insulating film 15.
  • the thickness of the second insulating film 27 is 5 ⁇ m in this embodiment, 3 to 10 ⁇ m in a wide range, and 5 to 10 ⁇ m in a narrow range. Since the thickness of the second insulating film 27 is sufficiently large as described above, the TFT 30 is not adversely affected by the impact at the time of pressing.
  • the second insulating film 27 has a plurality of openings 27A corresponding to the individual electrodes 31.
  • the opening 27A is a hole for exposing the individual electrode 31 during manufacturing, and is open to the upper electrode member 3 side.
  • the depth of the opening 27A matches the thickness of the second insulating film 27 described above.
  • the diameter of the opening 27A is 0.3 to 1.0 mm in a wide range and 0.4 to 0.6 mm in a narrow range.
  • the “diameter” is the diameter in the case of a circle, and the length of the longest line connecting the vertices facing each other through the center in the case of a polygon.
  • the edge of the opening 27A is located 20 ⁇ m to 300 ⁇ m radially outward from the outer peripheral edge of the individual pressure-sensitive layer 33.
  • the individual pressure-sensitive layers 33 may run on the second insulating film 27 and the sensitivity may vary. If the thickness exceeds 300 ⁇ m, a portion where the thin film transistor 30 cannot be protected occurs, and the reliability is reduced. Note that the edge of the opening 27A is preferably located at a position of 20 to 35 ⁇ m radially outward from the outer peripheral edge of the individual pressure-sensitive layer 33.
  • the lower electrode member 5 has a plurality of individual pressure-sensitive layers 33.
  • the plurality of individual pressure-sensitive layers 33 are provided in the plurality of openings 27A of the second insulating film 27, and extend from the plurality of openings 27A to the upper electrode member 3 side.
  • the upper surface of the individual pressure-sensitive layer 33 has a planar shape.
  • the individual pressure-sensitive layers 33 are respectively formed on the plurality of individual electrodes 31 and cover the individual electrodes 31.
  • the height H1 of the individual pressure-sensitive layer 33 is 20 ⁇ m in this embodiment, 15 to 25 ⁇ m in a wide range, and 18 to 22 ⁇ m in a narrow range.
  • the diameter L1 of the individual pressure-sensitive layer 33 is 0.3 to 1.0 mm in a wide range and 0.4 to 0.6 mm in a narrow range. It is preferable that the diameter L1 of the individual pressure-sensitive layer 33 has a certain length in order to ensure the overlap with the individual electrode 31.
  • the height H1 of the individual pressure-sensitive layer 33 can be adjusted by adjusting the diameter L1. This is because the film thickness changes depending on the size (diameter) of the pressure-sensitive layer. For example, as shown in FIG. 22, when the size of the pressure-sensitive layer is 0.5 mm or more, the thickness of the pressure-sensitive layer is approximately 20 ⁇ m.
  • the thickness of the pressure-sensitive layer decreases as the size decreases.
  • the pressure-sensitive layer size is 0.3 mm
  • the pressure-sensitive layer thickness is 15 ⁇ m
  • the pressure-sensitive layer size is 0.2 mm
  • the pressure-sensitive layer thickness is 11.27 ⁇ m
  • the pressure-sensitive layer size is 0.1 mm
  • the pressure-sensitive layer thickness is It becomes 5.06 ⁇ m.
  • the gap G1 between the individual electrode 31 and the upper electrode member 3 can be appropriately set from a wide range.
  • the gap G1 is 5 ⁇ m or more in this embodiment, but is, for example, 0 to several tens ⁇ m, and may be on the order of several ⁇ m or several tens ⁇ m.
  • the sensor 41 is formed by the individual electrodes 31 and the individual pressure-sensitive layers 33 described above.
  • a plurality of individual spacers 35 are formed on the main surface 27a of the second insulating film 27.
  • the plurality of individual pressure-sensitive layers 33 are arranged on a plane together with the plurality of individual electrodes 31.
  • the individual pressure-sensitive layers 33 and the individual spacers 35 are alternately arranged vertically and horizontally in plan view.
  • the plurality of individual pressure-sensitive layers 33 and the individual spacers 35 are arranged in a matrix.
  • matrix refers to a state in which two-dimensional arrangement is performed in a matrix or a state similar thereto.
  • the plurality of individual spacers 35 extend from the second insulating film 27 toward the upper electrode member 3 and are in contact with or close to the upper electrode member 3. As described above, since the plurality of individual spacers 35 are provided, the variation in sensitivity between the sensors 41 can be reduced, and therefore, erroneous detection is reduced.
  • the upper surface of the individual spacer 35 has a planar shape like the individual pressure-sensitive layer 33.
  • the height H2 and the diameter L2 of the individual spacer 35 are the same as or slightly smaller than the height H1 and the diameter L1 of the individual pressure-sensitive layer 33, respectively.
  • the sensitivity of the sensor 41 can be adjusted. If the gap G1 becomes smaller, the sensor 41 becomes more sensitive, and if the gap G1 becomes larger, the sensor 41 becomes less sensitive.
  • the sensitivity of the sensor 41 can be adjusted. If the density of the individual spacers 35 around the sensor 41 is low, the sensor 41 has high sensitivity, and if the density of the individual spacers 35 around the sensor 41 is high, the sensor 41 has low sensitivity.
  • the upper electrode member 3 and the lower electrode member 5 are bonded to each other by a frame spacer 13 at a peripheral portion.
  • the frame spacer 13 is formed in a frame shape and is made of, for example, an adhesive or a double-sided tape.
  • the upper electrode member 3 is pressed down, for example, by a finger, the common pressure-sensitive layer 11 and the individual pressure-sensitive layers 33 are electrically connected in the pressed area.
  • the depression may be performed with, for example, a finger, a stylus pen, a stick, a palm, or a sole.
  • the electrode pitch is, for example, 0.3 to 0.7 mm.
  • FIG. 4 is an equivalent circuit diagram of the pressure sensor.
  • the pressure sensor 1 has a circuit unit (not shown). The circuit unit controls the drain electrode 19, the source electrode 17, and the common electrode 9, and for example, according to a power supply voltage for applying a predetermined voltage to the common electrode 9 and the source electrode 17, and a current value between the source and the drain. And a current detection circuit for generating the output signal and outputting the generated signal to an external signal processing device.
  • the insulating film 7 and the insulating film 15 are engineering plastics such as polycarbonate, polyamide, or polyetherketone, or resin films such as acrylic, polyethylene terephthalate, or polybutylene terephthalate. Can be used.
  • the insulating film 7 requires elasticity, it is, for example, a urethane film, silicon, or rubber.
  • the insulating film 7 and the insulating film 15 are preferably made of a material having heat resistance because the electrodes are printed and dried.
  • a metal oxide film such as tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide, or indium tin oxide (ITO), or a composite mainly composed of these metal oxides It can be formed by a film or a metal film of gold, silver, copper, tin, nickel, aluminum, palladium, or the like.
  • ITO indium tin oxide
  • the common electrode 9 requires elasticity, it is, for example, an elastic Ag paste.
  • the individual pressure-sensitive layer 33 is made of, for example, a pressure-sensitive ink.
  • the pressure-sensitive ink is a material that enables pressure detection by changing the contact resistance between the electrodes facing each other in response to an external force.
  • the pressure-sensitive ink layer can be arranged by coating.
  • a printing method such as screen printing, offset printing, gravure printing, or flexographic printing, or application using a dispenser can be used.
  • the material of the individual spacer 35 is the same as the material of the individual pressure-sensitive layer 33.
  • FIGS. 5 to 15 are schematic cross-sectional views illustrating a method for manufacturing the pressure sensor. First, each step of the method of manufacturing the lower electrode member 5 will be described with reference to FIGS.
  • an electrode material 37 is formed on one surface of the insulating film 15 by, for example, sputtering.
  • the film exposed portion 39 is formed by removing a part of the electrode material 37 by, for example, a photolithography method.
  • a source electrode 17 and a drain electrode 19 are formed.
  • the method for forming the source electrode 17 and the drain electrode 19 is not particularly limited.
  • the organic semiconductor 23 is formed at the film exposed portion 39.
  • the method for forming the organic semiconductor 23 is a known technique.
  • the first insulating film 25 is formed so as to cover the surface on which the source electrode 17, the drain electrode 19, and the organic semiconductor 23 are formed.
  • a via hole reaching the drain electrode 19 is formed in the first insulating film 25 by laser, and a conductive material is buried in the via hole to form a conductive portion 29.
  • the via hole may be formed by a combination of photolithography and ashing.
  • a gate electrode 21 is formed by printing on the upper surface of the first insulating film 25 and above the organic semiconductor 23.
  • the technique for forming the gate electrode 21 is a known technique.
  • the individual electrode 31 is formed by a printing method, and is connected to the TFT 30 via the conductive portion 29. Since the gate electrode 21 and the individual electrode 31 can be formed at the same time, the number of steps is reduced. As a result, a plurality of TFTs 30 are formed so as to be spread on the main surface of the insulating film 15. In addition, a plurality of individual electrodes 31 facing the common electrode 9 are formed on the main surface of the plurality of TFTs 30 on the insulating film 7 side.
  • a second insulating film 27 is formed on the main surfaces of the plurality of TFTs 30.
  • the second insulating film 27 covers the entire first insulating film 25 on which the gate electrode 21 and the individual electrode 31 are formed.
  • the second insulating film 27 is made of, for example, a photoresist.
  • an opening 27A is formed in the second insulating film 27 at a position corresponding to the individual electrode 31, and the individual electrode 31 is exposed.
  • the opening 27A is formed by photolithography. Therefore, the dimensional accuracy of the opening 27A is improved. That is, variation in the size of the opening 27A is reduced, and variation in the sensitivity of the sensor 41 including the individual electrode 31 and the individual pressure-sensitive layer 33 is reduced.
  • the insulating film is formed by a printing method different from the present invention, the area of the opening must be increased in order to prevent the pressure-sensitive layer from being placed outside the opening and changing the sensitivity of the sensor. should not. However, if the area of the opening is increased, the durability near the opening is reduced.
  • the opening size of the opening 27A When the opening size of the opening 27A is small, the resistance of the individual electrode 31 and the individual pressure-sensitive layer 33 increases because the second insulating film 27 covers the individual electrode 31. In addition, since the individual pressure-sensitive layer 33 overlaps the upper surface of the second insulating film 27, the height of the individual pressure-sensitive layer 33 changes, so that the sensitivity varies. If the opening size is large, the gap in the second insulating film 27 becomes large, so that the thin film transistor 30 cannot be sufficiently protected.
  • the photoresist as the material of the second insulating film 27 may be, for example, a dry film type. The use of DFR can prevent the characteristics of the thin film transistor 30 from deteriorating due to the solvent. Note that the first insulating film 25 is as thin as about 1 ⁇ m, so that the thin film transistor 30 is easily damaged by a solvent in addition to physical damage.
  • the individual pressure-sensitive layers 33 and the individual spacers 35 are simultaneously formed by a printing method.
  • the individual pressure-sensitive layer 33 is formed in the opening 27A of the second insulating film 27, and the individual spacer 35 is formed on the main surface 27a.
  • the process is simplified, and thus the productivity is improved. Further, the displacement between the individual pressure-sensitive layer 33 and the individual spacer 35 is eliminated, and the sensitivity becomes accurate. Further, since the diameter of the individual pressure-sensitive layer 33 is sufficiently large, a deviation from the individual electrode 31 hardly occurs.
  • the individual pressure-sensitive layers 33 are present in the openings 27A, the heights of the individual pressure-sensitive layers 33 and the individual spacers 35 are made different even when the individual pressure-sensitive layers 33 and the individual spacers 35 are simultaneously printed. be able to. As a result, the gap between the common pressure-sensitive layer 11 and the individual pressure-sensitive layers 33 can be reduced.
  • the plurality of individual pressure-sensitive layers 33 are formed in the plurality of openings 27A formed in the second insulating film 27. Therefore, it is not necessary to form a via hole and fill a conductive material in the second insulating film 27. As a result, the thickness of the second insulating film 27 can be increased, and as a result, the reliability of the pressure sensor 1 against stress increases. In addition, good results can be provided for environmental tests.
  • a common electrode 9 is formed on the entire main surface of the insulating film 7 by a printing method.
  • the material of the common electrode 9 may be formed on the entire main surface of the insulating film 7 by, for example, sputtering, and then the common electrode 9 may be formed by photolithography.
  • a common pressure-sensitive layer 11 is formed on the entire main surface of the common electrode 9 by a printing method.
  • the pressure sensor 1 is completed by bonding the upper electrode member 3 and the lower electrode member 5 via a frame spacer 13 (FIG. 1) made of an adhesive.
  • FIG. 16 is a schematic sectional view of the pressure sensor according to the second embodiment of the present invention.
  • FIG. 17 is a schematic plan view showing a planar positional relationship between an individual electrode and an individual spacer. Since the basic structure is the same as that of the first embodiment, only different points will be described.
  • the diameter L2 of the individual spacer 35A is smaller than the diameter L1 of the individual pressure-sensitive layer 33A. For example, the diameter L2 of the individual spacer 35A is less than 0.3 mm. In this case, the individual spacer 35A is lower than the individual pressure-sensitive layer 33A. Therefore, the total height of the individual spacers 35A added to the second insulating film 27 does not become too high.
  • the gap G2 between the individual pressure-sensitive layer 33A and the upper electrode member 3 can be controlled to be small.
  • the gap G2 is preferably smaller than 5 ⁇ m.
  • the individual pressure-sensitive layers and the individual spacers have a flat plate shape in side view and a square shape in plan view, but the shape is not particularly limited.
  • An example in which the side surfaces of the individual pressure-sensitive layer and the individual spacer are mountain-shaped and round in plan view will be described with reference to FIGS. 18 and 19.
  • FIG. 18 is a schematic sectional view of the pressure sensor according to the third embodiment of the present invention.
  • FIG. 19 is a schematic plan view showing a planar positional relationship between an individual electrode and an individual spacer.
  • the individual pressure-sensitive layer 33B has a mountain shape.
  • the “mountain shape” has a vertex or a vertex portion, and has a shape that becomes lower as it spreads from there around. In this case, the measurement pressure range is widened.
  • FIG. 20 is a schematic sectional view of the pressure sensor according to the fourth embodiment of the present invention.
  • the upper electrode member 3A is a planar member on which a pressing force acts.
  • the upper electrode member 3A has an insulating film 7 and a common electrode 9 formed on the entire lower surface thereof, that is, over the entire surface or by patterning.
  • FIG. 21 is a schematic sectional view of the pressure sensor according to the fifth embodiment of the present invention.
  • the upper electrode member 3A is a planar member on which a pressing force acts.
  • the upper electrode member 3A has an insulating film 7 and a common electrode 9 formed on the entire lower surface thereof, that is, over the entire surface or by patterning.
  • the TFT is a top gate type, but may be a bottom gate type. Such an embodiment will be described with reference to FIG.
  • FIG. 23 is a schematic sectional view of the pressure sensor according to the sixth embodiment.
  • the lower electrode member 5C of the pressure sensor 1C has a plurality of TFTs 30C.
  • the plurality of TFTs 30C are provided on the main surface of the insulating film 15C on the insulating film 7C side so as to face the common electrode 9C.
  • the TFT 30C is a bottom gate type, and the source electrode 17C, the drain electrode 19C, and the organic semiconductor 23C are formed on the first insulating film 25c.
  • the gate electrode 21C is formed on the insulating film 15C.
  • the lower electrode member 5C has a plurality of individual electrodes 31C.
  • the plurality of individual electrodes 31C are provided on the main surface of the plurality of TFTs 30C on the insulating film 7C side, and one is connected to one or two or more adjacent TFTs 30C. More specifically, the individual electrode 31C is formed on the bottom portion of the opening 27D, and is connected to the conducting portion 29C.
  • the pressure sensor 1 has a plurality of individual pressure-sensitive layers 33C.
  • the plurality of individual pressure-sensitive layers 33C are provided in the plurality of openings 27D of the second insulating film 27, and extend from the plurality of openings 27D toward the upper electrode member 3C.
  • a plurality of individual spacers 35C are formed on the main surface 27a of the second insulating film 27C. Specifically, the plurality of individual pressure-sensitive layers 33C are arranged in a plane with the plurality of individual electrodes 31C. The plurality of individual spacers 35 extend from the second insulating film 27C toward the upper electrode member 3C, and are in contact with or close to the upper electrode member 3C.
  • FIGS. 24 to 30 are schematic sectional views illustrating a method for manufacturing the pressure sensor.
  • a gate electrode 21C is formed on a part of the main surface of the insulating film 15C by, for example, sputtering.
  • a first insulating film 25C is formed so as to cover the surface on which the gate electrode 21C is formed.
  • a source electrode 17C, a drain electrode 19C, and an individual electrode 31C are formed on a part of the main surface of the first insulating film 25C by, for example, sputtering.
  • the drain electrode 19C and the individual electrode 31C are connected by a conduction portion 29C.
  • an organic semiconductor 23C is formed between the source electrode 17C and the drain electrode 19C.
  • the method for forming the organic semiconductor 23C is a known technique.
  • a plurality of TFTs 30C are formed on the main surface of the insulating film 15C.
  • a plurality of individual electrodes 31C facing the common electrode 9 are formed on the main surface of the plurality of TFTs 30C on the insulating film 7 side.
  • a second insulating film 27C is formed on the main surfaces of the plurality of TFTs 30.
  • the second insulating film 27C covers the entire first insulating film 25C on which the source electrode 17C, the drain electrode 19C, and the individual electrode 31C are formed.
  • the second insulating film 27C is made of, for example, a photoresist.
  • an opening 27D is formed at a position corresponding to the individual electrode 31C in the second insulating film 27C, and the individual electrode 31C is exposed. Specifically, the opening 27D is formed by photolithography.
  • the individual pressure-sensitive layers 33C and the individual spacers 35C are simultaneously formed by a printing method.
  • the individual pressure-sensitive layer 33C is formed in the opening 27D of the second insulating film 27C, and the individual spacer 35C is formed on the main surface 27a of the second insulating film 27C.
  • the drain electrode 19C exists on the upper surface of the first insulating film 25C, like the individual electrode 31C. Therefore, the conductive portion 29C connecting the drain electrode 19C and the individual electrode 31C can be formed simultaneously with the drain electrode 19C and the individual electrode 31C. As a result, it is not necessary to form a via hole for the conduction portion in the first insulating film 25C by using a laser.
  • the individual electrodes 31 and the individual spacers 35 are in the form of a matrix in which rows and columns are completely aligned, but may be arranged in a matrix in a broad sense.
  • a thin film transistor is associated with each individual electrode, and the current of each thin film transistor is detected.
  • one thin film transistor is connected to one individual electrode.
  • a plurality of thin film transistors may be associated with one individual electrode, and currents of the plurality of thin film transistors may be detected.
  • two or more thin film transistors adjacent to one individual electrode are connected. As a result, the detected current value increases, and the circuit can be provided with redundancy.
  • the individual pressure-sensitive layers and the individual spacers are alternately arranged, but the positional relationship between them is not particularly limited.
  • the individual pressure-sensitive layers may be adjacent to each other in either the row direction or the column direction or both.
  • the individual spacers may be adjacent to each other in one or both of the row direction and the column direction.
  • the predetermined voltage is applied to the common electrode formed on the upper electrode member and the source electrode of the thin film transistor (TFT) formed on the lower electrode member.
  • wiring for a power supply voltage (not shown) is connected to each of the upper electrode member and the lower electrode member.
  • the wiring for applying the predetermined voltage may be collectively connected to only the lower electrode member.
  • the lower electrode member 5 of the pressure sensor 1 includes a plurality of first individual electrodes 311 and a plurality of first individual electrodes 311 on the main surfaces of the plurality of TFTs 30.
  • a plurality of individual electrodes 312 arranged in a state of being insulated from each other are provided.
  • a plurality of first openings 271 corresponding to the first individual electrodes 311 and a plurality of second openings 272 corresponding to the plurality of second individual electrodes 312 are provided on the main surface of the plurality of TFTs 30.
  • a plurality of second insulating films 27 are provided.
  • One of the plurality of first individual electrodes 311 is connected to one or two or more adjacent TFTs 30.
  • the plurality of first openings 271 corresponding to the first individual electrodes 311 of the second insulating film 27 have a plurality of first individual pressure-sensitive layers 331 provided on the first individual electrodes 311.
  • a predetermined voltage is applied to the source electrode 17 and the second individual electrode 312 of the TFT 30 formed on the lower electrode member 5.
  • the first individual electrode 311 and the second individual electrode 312 of the lower electrode member 5 are conducted through the common electrode 9 of the upper electrode member 3 when pressed.
  • the wiring for applying and applying the predetermined voltage can be collectively connected to only the lower electrode member 5, so that the replacement of the upper electrode member 3 can be easily performed. For example, when the upper electrode member 3 is deteriorated or damaged, the upper electrode member 3 is replaced with a new one.
  • the upper electrode member 3 has the common pressure-sensitive layer 11 as shown in FIG.
  • the first individual pressure-sensitive layer 331 and the second individual pressure-sensitive layer 332 may have different heights.
  • the second individual pressure-sensitive layer 332 can also serve as a spacer function, so that the individual spacer 35 as shown in FIG. 31 may not be provided.
  • the present invention can be widely applied to a pressure sensor having a pressure-sensitive layer and a large number of thin film transistors as electrodes.
  • the pressure sensor according to the present invention is suitable for a large-area sheet sensor other than the touch panel.
  • the pressure sensor according to the present invention can be applied to a walking measurement technology (medical, sports, and security fields) and a bed bedsore measurement technology.
  • pressure sensor 3 upper electrode member 5: lower electrode member 7: insulating film 9: common electrode 11: common pressure-sensitive layer 15: insulating film 25: first insulating film 27: second insulating film 27A: opening 27a : Main surface 29: Conductive part 30: Thin film transistor 31: Individual electrode 33: Individual pressure-sensitive layer 35: Individual spacer 41: Sensor 271: First opening 272: Second opening 311: First individual electrode 312: Second individual Electrode 331: first individual pressure-sensitive layer 332: second individual pressure-sensitive layer

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Ceramic Engineering (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Computer Hardware Design (AREA)
  • Force Measurement Appropriate To Specific Purposes (AREA)
  • Pressure Sensors (AREA)
PCT/JP2019/027456 2018-07-23 2019-07-11 圧力センサ及び圧力センサの製造方法 WO2020022078A1 (ja)

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JP6316371B2 (ja) * 2016-10-13 2018-04-25 Ｎｉｓｓｈａ株式会社 圧力センサ
JP6325639B1 (ja) * 2016-11-22 2018-05-16 Ｎｉｓｓｈａ株式会社 圧力センサ

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6316371B2 (ja) * 2016-10-13 2018-04-25 Ｎｉｓｓｈａ株式会社 圧力センサ
JP6325639B1 (ja) * 2016-11-22 2018-05-16 Ｎｉｓｓｈａ株式会社 圧力センサ

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