WO2020153289A1 - Élément piézoélectrique - Google Patents

Élément piézoélectrique Download PDF

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Publication number
WO2020153289A1
WO2020153289A1 PCT/JP2020/001688 JP2020001688W WO2020153289A1 WO 2020153289 A1 WO2020153289 A1 WO 2020153289A1 JP 2020001688 W JP2020001688 W JP 2020001688W WO 2020153289 A1 WO2020153289 A1 WO 2020153289A1
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WIPO (PCT)
Prior art keywords
region
main surface
electrode layer
electrode
piezoelectric
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PCT/JP2020/001688
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English (en)
Japanese (ja)
Inventor
佳生 太田
寿一 志村
茂 坂野
英也 坂本
一志 立本
明丈 武田
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Tdk株式会社
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Publication of WO2020153289A1 publication Critical patent/WO2020153289A1/fr

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/87—Electrodes or interconnections, e.g. leads or terminals
    • H10N30/872—Interconnections, e.g. connection electrodes of multilayer piezoelectric or electrostrictive devices
    • H10N30/874—Interconnections, e.g. connection electrodes of multilayer piezoelectric or electrostrictive devices embedded within piezoelectric or electrostrictive material, e.g. via connections
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/50—Piezoelectric or electrostrictive devices having a stacked or multilayer structure
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/87—Electrodes or interconnections, e.g. leads or terminals
    • H10N30/875—Further connection or lead arrangements, e.g. flexible wiring boards, terminal pins

Definitions

  • One aspect of the present invention relates to a piezoelectric element.
  • Patent Document 1 includes an element body having a first main surface and a second main surface facing each other, an internal electrode arranged inside the element body, and an external electrode arranged on the first main surface. Piezoelectric elements are described. In this piezoelectric element, the external electrodes have rounded corners. Therefore, even when the outer edge of the external electrode serves as a boundary between the active region and the inactive region, stress is suppressed from being concentrated on the corner portion of the external electrode.
  • a wiring member may be connected to the external electrode. In this case, improvement in connection reliability between the external electrode and the wiring member is required.
  • One aspect of the present invention provides a piezoelectric element capable of improving connection reliability between an external electrode and a wiring member.
  • a piezoelectric element includes an element body, internal electrodes, and external electrodes.
  • the element body has a first main surface and a second main surface facing each other.
  • the internal electrode is arranged in the body.
  • the external electrode is arranged on the first main surface.
  • the first main surface has a first region and a second region.
  • External electrodes are arranged in the first region.
  • the second region has a frame shape and surrounds the first region.
  • the height of the first area from the reference surface is higher than the height of the second area from the reference surface. Since the external electrode is arranged in the first region, the external electrode is in a state of protruding from the surrounding second region. Therefore, as compared with the case where the external electrode is recessed from the surrounding second region, the bonding strength of the wiring member to the external electrode can be easily increased. As a result, the connection reliability between the external electrode and the wiring member can be improved.
  • the first main surface may further have a third region surrounding the second region.
  • the height of the third region from the reference surface may be lower than the height of the first region from the reference surface and higher than the height of the second region from the reference surface.
  • the external electrodes are in a state of protruding also from the third region. Therefore, the connection reliability between the external electrode and the wiring member can be further improved.
  • the first main surface may further have a third region surrounding the second region.
  • the roughness of the first region may be greater than the roughness of the third region.
  • the bonding strength between the external electrode and the first region is improved.
  • the connection reliability between the external electrode and the wiring member can be further improved.
  • the waviness of the first main surface may be larger than that of the second main surface.
  • the waviness of the second main surface is relatively small, when the vibrated body is brought into contact with the second main surface, the vibration is easily transmitted to the vibrated body.
  • a piezoelectric element capable of improving connection reliability between an external electrode and a wiring member.
  • FIG. 1 is a plan view of a piezoelectric element according to an embodiment.
  • FIG. 2 is a sectional view taken along the line II-II of FIG.
  • FIG. 3 is an exploded perspective view of the piezoelectric element shown in FIG.
  • FIG. 4 is a plan view of the element body of FIG.
  • FIG. 5 is a sectional view taken along the line VV of FIG.
  • FIG. 6 is a sectional view taken along line VI-VI in FIG.
  • FIG. 7 is a cross-sectional view showing a state in which a wiring member is connected to the piezoelectric element of FIG.
  • FIG. 8 is a graph showing a measurement sectional curve of each region.
  • FIG. 1 is a plan view of a piezoelectric element according to an embodiment.
  • FIG. 2 is a sectional view taken along the line II-II of FIG.
  • FIG. 3 is an exploded perspective view of the piezoelectric element of FIG.
  • the piezoelectric element 10 according to the embodiment has an element body 11 and a plurality of external electrodes 13 and 15.
  • the piezoelectric element 10 has a pair of external electrodes 13 and 15.
  • the body 11 has a rectangular parallelepiped shape.
  • the element body 11 has a pair of main surfaces 11a and 11b facing each other, a pair of side surfaces 11c facing each other, and a pair of side surfaces 11e facing each other.
  • the rectangular parallelepiped shape includes, for example, a rectangular parallelepiped shape with chamfered corners and ridges, and a rectangular parallelepiped shape with rounded corners and ridges.
  • the direction in which the pair of main surfaces 11a and 11b face each other is the first direction D1.
  • the first direction D1 is also a direction orthogonal to the main surfaces 11a and 11b.
  • the direction in which the pair of side surfaces 11c face each other is the second direction D2.
  • the second direction D2 is also a direction orthogonal to each side surface 11c.
  • the direction in which the pair of side surfaces 11e faces each other is the third direction D3.
  • the third direction D3 is also a direction orthogonal to each side surface 11e.
  • Each main surface 11a, 11b has a rectangular shape.
  • Each main surface 11a, 11b has a rectangular shape having a pair of long sides and a pair of short sides. That is, the piezoelectric element 10 (element body 11) has a rectangular shape having a pair of long sides and a pair of short sides in a plan view.
  • the rectangular shape includes, for example, a shape in which each corner is chamfered and a shape in which each corner is rounded.
  • the long side direction of the main surfaces 11a and 11b coincides with the third direction D3.
  • the short side direction of the principal surfaces 11a and 11b coincides with the second direction D2.
  • the swell of the main surface 11a is larger than that of the main surface 11b.
  • the waviness is, for example, the average length (RSm) of roughness curve elements in the long side direction (third direction D3) of the main surface 11a.
  • the main surface 11a is a surface in which peaks and valleys are formed along the long side direction of the main surface 11a. Mountains and valleys are alternately arranged on the main surface 11a along the long side direction of the main surface 11a.
  • the average length (RSm) of roughness curve elements in the long side direction of the main surface 11a is the average length (RSm) of roughness curve elements in the short side direction (second direction D2) of the main surface 11a. ) Is formed to be larger than.
  • the main surface 11a is formed so that the peaks and valleys have anisotropy.
  • the main surface 11b is a substantially flat surface, and the average length (RSm) of roughness curve elements in the long side direction of the main surface 11b is the average length of roughness curve elements in the short side direction of the main surface 11b. (RSm).
  • the average length (RSm) of the roughness curve elements in the long side direction of the main surface 11a is, for example, 50 ⁇ m or more and 80 ⁇ m or less, and the average length (RSm) of the roughness curve elements in the short side direction of the main surface 11a is For example, it is 20 ⁇ m or more and 50 ⁇ m or less.
  • the average length (RSm) of the roughness curve elements in the long side direction and the short side direction of the main surface 11b is, for example, 20 ⁇ m or more and 50 ⁇ m or less.
  • the pair of side surfaces 11c extends in the first direction D1 so as to connect the pair of main surfaces 11a and 11b.
  • the pair of side surfaces 11c also extends in the third direction D3.
  • the pair of side surfaces 11e extends in the first direction D1 so as to connect the pair of main surfaces 11a and 11b.
  • the pair of side surfaces 11e also extends in the second direction D2.
  • the length of the element body 11 in the second direction D2 is, for example, 10 mm.
  • the length of the element body 11 in the third direction D3 is, for example, 20 mm.
  • the length (thickness) of the element body 11 in the first direction D1 is, for example, 500 ⁇ m.
  • Each main surface 11a, 11b and each side surface 11c, 11e may be indirectly adjacent to each other. In this case, a ridge line portion is located between each main surface 11a, 11b and each side surface 11c, 11e.
  • the element body 11 is configured by laminating a plurality of piezoelectric layers 17a, 17b, 17c, 17d, 17e in the first direction D1.
  • the element body 11 has a plurality of stacked piezoelectric layers 17a, 17b, 17c, 17d, 17e.
  • the element body 11 has five piezoelectric layers 17a, 17b, 17c, 17d and 17e.
  • the direction in which the plurality of piezoelectric layers 17a, 17b, 17c, 17d, and 17e are stacked coincides with the first direction D1.
  • the piezoelectric layer 17a has a main surface 11a.
  • the piezoelectric layer 17e has a main surface 11b.
  • the piezoelectric layers 17b, 17c, 17d are located between the piezoelectric layers 17a and 17e.
  • Each piezoelectric layer 17a, 17b, 17c, 17d, 17e is made of a piezoelectric ceramic material. That is, the element body 11 is made of a piezoelectric ceramic material.
  • the piezoelectric ceramic material include PZT[Pb(Zr,Ti)O 3 ], PT(PbTiO 3 ), PLZT[(Pb,La)(Zr,Ti)O 3 ], PZN[Pb(Zn,Nb). O 3 ], or barium titanate (BaTiO 3 ) is used.
  • Each of the piezoelectric layers 17a, 17b, 17c, 17d, 17e is made of, for example, a sintered body of a ceramic green sheet containing the above-mentioned piezoelectric ceramic material.
  • the piezoelectric layers 17a, 17b, 17c, 17d and 17e are integrated so that the boundaries between the piezoelectric layers 17a, 17b, 17c, 17d and 17e cannot be recognized.
  • each piezoelectric layer 17a, 17b, 17c, 17d, 17e in the first direction D1 is, for example, 40 ⁇ m.
  • the piezoelectric layer 17a has such a transparency that an electrode layer 21 described later can be visually recognized from the main surface 11a side through the piezoelectric layer 17a.
  • the other piezoelectric layers 17b, 17c, 17d, 17e have the same transparency as the piezoelectric layer 17a.
  • the piezoelectric element 10 includes a plurality of electrode layers 21, 22, 23, 24 arranged in the element body 11.
  • the piezoelectric element 10 includes four electrode layers 21, 22, 23 and 24.
  • Each electrode layer 21, 22, 23, 24 is an internal electrode.
  • Each electrode layer 21, 22, 23, 24 is made of a conductive material.
  • As the conductive material for example, Ag, Pd, or Ag-Pd alloy is used.
  • Each of the electrode layers 21, 22, 23, 24 is configured as, for example, a sintered body of a conductive paste containing the above conductive material.
  • the respective electrode layers 21, 22, 23, 24 are arranged at different positions (layers) in the first direction D1.
  • the main surface 11a and the electrode layer 21 face each other with a space in the first direction D1.
  • the electrode layer 21 and the electrode layer 22 face each other with a space in the first direction D1.
  • the electrode layer 22 and the electrode layer 23 face each other with a space in the first direction D1.
  • the electrode layer 23 and the electrode layer 24 face each other with a space in the first direction D1.
  • the electrode layer 24 and the main surface 11b are opposed to each other with a space in the first direction D1.
  • the electrode layer 21 is located between the piezoelectric layers 17a and 17b.
  • the electrode layer 22 is located between the piezoelectric layer 17b and the piezoelectric layer 17c.
  • the electrode layer 23 is located between the piezoelectric layer 17c and the piezoelectric layer 17d.
  • the electrode layer 24 is located between the piezoelectric layer 17d and the piezoelectric layer 17e.
  • the electrode layers 21, 22, 23, 24 are not exposed on the surface of the element body 11. That is, the electrode layers 21, 22, 23, and 24 are provided apart from the side surfaces 11c and 11e, and are not exposed on the side surfaces 11c and 11e. Each electrode layer 21, 22, 23, 24 is separated from all edges (four sides) of the main surfaces 11a, 11b when viewed in the first direction D1.
  • Each electrode layer 21, 22, 23, 24 has a rectangular shape when viewed from the first direction D1.
  • Each electrode layer 21, 22, 23, 24 has a rectangular shape having a pair of long sides and a pair of short sides when viewed from the first direction D1 (in plan view).
  • the long side direction of each electrode layer 21, 22, 23, 24 coincides with the third direction D3.
  • the short side direction of each electrode layer 21, 22, 23, 24 corresponds to the second direction D2.
  • the outer edges of the electrode layers 21, 22, 23, and 24 have the same shape and coincide with each other.
  • each electrode layer 21, 22, 23, 24 When viewed from the first direction D1, the four corners of each electrode layer 21, 22, 23, 24 are round and have a so-called R shape.
  • the rounded corner does not mean a corner formed by the intersection of two straight lines, but a curved corner formed by connecting ends of two straight lines with a curved line.
  • the external electrodes 13 and 15 are arranged on the main surface 11a.
  • the external electrode 13 and the external electrode 15 are arranged in the third direction D3.
  • the external electrode 13 and the external electrode 15 are adjacent to each other in the third direction D3.
  • the external electrodes 13 and 15 are separated from all the edges (four sides) of the main surface 11a when viewed in the first direction D1.
  • Each of the external electrodes 13 and 15 has a rectangular shape when viewed from the first direction D1.
  • the rectangular shape includes, for example, a shape in which each corner is chamfered and a shape in which each corner is rounded.
  • the pair of external electrodes 13 and 15 have the same shape when viewed from the first direction D1.
  • the short side direction of each external electrode 13, 15 matches the second direction D2
  • the long side direction of each external electrode 13, 15 matches the third direction D3.
  • the length of each external electrode 13, 15 in the second direction D2 is, for example, 3 mm.
  • the length of each external electrode 13, 15 in the third direction D3 is, for example, 3.6 mm.
  • the distance between the pair of external electrodes 13 and 15 in the third direction D3 is, for example, 3.4 mm.
  • each of the external electrodes 13 and 15 Since each of the external electrodes 13 and 15 is formed on the main surface 11a having the above-described shape, it has a shape that follows the shape of the main surface 11a. That is, the ridges and valleys of the main surface 11a are reflected on the outer surfaces of the external electrodes 13 and 15.
  • the thickness (length in the first direction D1) of each external electrode 13, 15 is, for example, 1.5 ⁇ m or more and 3.0 ⁇ m or less.
  • Each external electrode 13, 15 is made of a conductive material.
  • the conductive material for example, Ag, Pd, or Ag-Pd alloy is used.
  • Each of the external electrodes 13 and 15 is formed, for example, as a sintered body of a conductive paste containing the above conductive material.
  • the external electrode 13 is electrically connected to the connection conductor 25 through the via conductor 31.
  • the connection conductor 25 is located in the same layer as the electrode layer 21.
  • the connection conductor 25 is located inside the electrode layer 21.
  • An opening is formed in the electrode layer 21 at a position corresponding to the external electrode 13 when viewed in the first direction D1.
  • the connection conductor 25 is located in the opening formed in the electrode layer 21. When viewed in the first direction D1, all the edges of the connection conductor 25 are surrounded by the electrode layer 21.
  • connection conductor 25 is located between the piezoelectric layer 17a and the piezoelectric layer 17b.
  • the electrode layer 21 and the connection conductor 25 are separated from each other.
  • the connection conductor 25 faces the external electrode 13 in the first direction D1.
  • the via conductor 31 is connected to the external electrode 13 and the connection conductor 25.
  • the connection conductor 25 is electrically connected to the electrode layer 22 through the via conductor 32.
  • the connection conductor 25 faces the electrode layer 22 in the first direction D1.
  • the via conductor 32 is connected to the connection conductor 25 and the electrode layer 22.
  • the electrode layer 22 is electrically connected to the connection conductor 26 through the via conductor 32.
  • the connection conductor 26 is located in the same layer as the electrode layer 23.
  • the connection conductor 26 is located inside the electrode layer 23.
  • An opening is formed in the electrode layer 23 at a position corresponding to the external electrode 13 (connection conductor 25) when viewed in the first direction D1.
  • the connection conductor 26 is located in the opening formed in the electrode layer 23. When viewed in the first direction D1, all the edges of the connection conductor 26 are surrounded by the electrode layer 23.
  • connection conductor 26 is located between the piezoelectric layers 17c and 17d.
  • the electrode layer 23 and the connection conductor 26 are separated from each other.
  • the connection conductor 26 faces the electrode layer 22 in the first direction D1.
  • the via conductor 33 is connected to the electrode layer 22 and the connection conductor 26.
  • the connection conductor 26 is electrically connected to the electrode layer 24 through the via conductor 34.
  • the connection conductor 26 faces the electrode layer 24 in the first direction D1.
  • the via conductor 34 is connected to the connection conductor 26 and the electrode layer 24.
  • the external electrode 15 is electrically connected to the electrode layer 21 through the via conductor 35.
  • the electrode layer 21 faces the external electrode 15 in the first direction D1.
  • the via conductor 35 is connected to the external electrode 15 and the electrode layer 21.
  • the electrode layer 21 is electrically connected to the connection conductor 27 through the via conductor 36.
  • the connection conductor 27 is located in the same layer as the electrode layer 22.
  • the connection conductor 27 is located inside the electrode layer 22.
  • An opening is formed in the electrode layer 22 at a position corresponding to the external electrode 15 when viewed in the first direction D1.
  • the connection conductor 27 is located in the opening formed in the electrode layer 22. When viewed from the first direction D1, all the edges of the connection conductor 27 are surrounded by the electrode layer 22.
  • connection conductor 27 is located between the piezoelectric layers 17b and 17c.
  • the electrode layer 22 and the connection conductor 27 are separated from each other.
  • the connection conductor 27 faces the electrode layer 21 in the first direction D1.
  • the via conductor 36 is connected to the electrode layer 21 and the connection conductor 27.
  • the connection conductor 27 is electrically connected to the electrode layer 23 through the via conductor 37.
  • the connection conductor 27 faces the electrode layer 23 in the first direction D1.
  • the via conductor 37 is connected to the connection conductor 27 and the electrode layer 23.
  • the electrode layer 23 is electrically connected to the connection conductor 28 through the via conductor 38.
  • the connection conductor 28 is located in the same layer as the electrode layer 24.
  • the connection conductor 28 is located inside the electrode layer 24.
  • An opening is formed in the electrode layer 24 at a position corresponding to the external electrode 15 when viewed in the first direction D1.
  • the connection conductor 28 is located in the opening formed in the electrode layer 24. When viewed in the first direction D1, all the edges of the connection conductor 28 are surrounded by the electrode layer 24.
  • connection conductor 28 is located between the piezoelectric layer 17d and the piezoelectric layer 17e.
  • the electrode layer 24 and the connection conductor 28 are separated from each other.
  • the connection conductor 28 faces the electrode layer 23 in the first direction D1.
  • the via conductor 38 is connected to the electrode layer 23 and the connection conductor 28.
  • the external electrode 13 is electrically connected to the via conductor 31, the connection conductor 25, the via conductor 32, the electrode layer 22, the via conductor 33, the connection conductor 26, the via conductor 34, and the electrode layer 24.
  • the external electrode 15 is electrically connected to the via conductor 35, the electrode layer 21, the via conductor 36, the connection conductor 27, the via conductor 37, the electrode layer 23, the via conductor 38, and the connection conductor 28.
  • connection conductors 25, 26, 27, 28 and the via conductors 31, 32, 33, 34, 35, 36, 37, 38 are made of a conductive material.
  • a conductive material for example, Ag, Pd, or Ag-Pd alloy is used.
  • the connection conductors 25, 26, 27, 28 and the via conductors 31, 32, 33, 34, 35, 36, 37, 38 are configured, for example, as a sintered body of a conductive paste containing the conductive material.
  • the connection conductors 25, 26, 27, 28 have a rectangular shape when viewed from the first direction D1.
  • the via conductors 31, 32, 33, 34, 35, 36, 37, 38 are conductive materials filled in through holes formed in the ceramic green sheet for forming the corresponding piezoelectric layers 17a, 17b, 17c, 17d.
  • the conductive paste is formed by sintering.
  • the conductor electrically connected to the electrode layers 21 and 23 and the conductor electrically connected to the electrode layers 22 and 24 are not arranged on the main surface 11b of the element body 11.
  • the entire main surface 11b is exposed.
  • the conductors electrically connected to the electrode layers 21 and 23 nor the conductors electrically connected to the electrode layers 22 and 24 are arranged on the respective side faces 11c and 11e of the element body 11.
  • each side surface 11c is viewed from the second direction D2
  • each side surface 11c is entirely exposed.
  • each side surface 11e is viewed from the third direction D3, the entire side surface 11e is exposed.
  • the region sandwiched by the layer 24 constitutes a piezoelectrically active active region. That is, in the element body 11, active regions are formed between the electrode layer 21 and the electrode layer 22, between the electrode layer 22 and the electrode layer 23, and between the electrode layer 23 and the electrode layer 24.
  • the outer edges of the electrode layers 21, 22, 23, and 24 are boundaries between the active regions and the piezoelectrically inactive inactive regions.
  • the active region is located so as to surround the plurality of external electrodes 13 and 15 when viewed from the first direction D1.
  • the element body 11 When viewed from the first direction D1, the element body 11 includes an active region in a region located between the external electrode 13 and the external electrode 15. When viewed from the first direction D1, the element body 11 also includes an active region outside the region where the external electrodes 13 and 15 are located.
  • FIG. 4 is a plan view of the element body of FIG.
  • the main surface 11a of the element body 11 has a first region R1, a second region R2, a third region R3, and a fourth region R4.
  • the main surface 11a has a pair of first regions R1, a pair of second regions R2, one third region R3, and one fourth region R4.
  • the external electrodes 13 and 15 are arranged in each of the first regions R1.
  • Each first region R1 overlaps each external electrode 13, 15 when viewed from the first direction D1.
  • Each first region R1 has a rectangular shape.
  • the rectangular shape includes, for example, a shape in which each corner is chamfered and a shape in which each corner is rounded.
  • the pair of first regions R1 are arranged in the third direction D3.
  • the pair of first regions R1 are adjacent to each other in the third direction D3.
  • the pair of first regions R1 are separated from each other.
  • Each first region R1 is separated from all edges (four sides) of the main surface 11a when viewed in the first direction D1.
  • each first region R1 is located outside each external electrode 13, 15 when viewed from the first direction D1. That is, when viewed from the first direction D1, the area of each first region R1 is larger than the area of each external electrode 13, 15.
  • Each second area R2 surrounds each first area R1.
  • Each second region R2 surrounds the entire first region R1.
  • Each second region R2 has a frame shape (for example, a rectangular frame shape).
  • the width of each second region R2 is substantially constant over the entire circumference of each second region R2.
  • the width of each second region R2 (the length between the inner edge and the outer edge of the second region R2) is, for example, 0.2 mm or more and 1.0 mm or less, for example, 0.4 mm.
  • the inner edge of each second region R2 matches the outer edge of each first region R1.
  • the pair of second regions R2 are separated from each other.
  • the second region R2 is arranged between the first region R1 and the third region R3.
  • the third region R3 surrounds both the pair of second regions R2.
  • the outer edge of the third region R3 has a rectangular shape.
  • the outer edge of the third region R3 is separated from the outer edge of the main surface 11a.
  • the third region R3 is arranged between the second region R2 and the fourth region R4 and between a pair of adjacent second regions R2.
  • the third region R3 overlaps the electrode layer 21 when viewed in the first direction D1.
  • the third region R3 overlaps with the active regions of the respective piezoelectric layers 17b, 17c, 17d when viewed from the first direction D1.
  • the third region R3 has the same shape as the active regions of the piezoelectric layers 17b, 17c, 17d when viewed from the first direction D1.
  • the fourth area R4 surrounds the entire third area R3.
  • the fourth region R4 has a frame shape (for example, a rectangular frame shape).
  • the width of the fourth region R4 is substantially constant over the entire circumference of the fourth region R4.
  • the width of the fourth region R4 (the length between the inner edge and the outer edge of the fourth region R4) is, for example, 0.2 mm or more and 0.8 mm or less, for example 0.3 mm.
  • the inner edge of the fourth region R4 matches the outer edge of the third region R3.
  • the outer edge of the fourth region R4 matches the outer edge of the main surface 11a.
  • the fourth region R4 is an outer edge portion of the main surface 11a.
  • FIG. 5 is a sectional view taken along the line VV of FIG.
  • FIG. 6 is a sectional view taken along line VI-VI in FIG. 5 and 6 schematically show sectional views in which the inclination of the reference plane, noise, defects, and waviness components are corrected.
  • the height of the first region R1 from the reference surface is the height of the second region R2 from the reference surface. Higher than that.
  • the heights of the regions R1 to R4 from the reference plane will be simply referred to as the heights of the regions R1 to R4.
  • the height of each of the regions R1 to R4 is the length in the first direction D1 from the reference surface to each of the regions R1 to R4.
  • the reference plane may be, for example, a plane including the average line (JIS-B0601 (1994)) of the sectional curve of the main surface 11b.
  • the reference surface may be, for example, a flat surface that is in contact with the main surface 11b, and when the piezoelectric element 10 is placed on a flat surface such that the main surface 11b is in contact with the flat surface, the reference surface may be the reference surface.
  • the height of each of the regions R1 to R4 is, for example, the height from the reference plane of the average line (JIS-B0601 (1994)) of the sectional curve of each of the regions R1 to R4.
  • the height of the third region R3 is lower than the height of the first region R1 and higher than the height of the second region R2.
  • the height of the first region R1 is higher than the height of the fourth region R4.
  • the height of the second region R2 is equal to the height of the fourth region R4.
  • the difference between the height of the first region R1 and the height of R2 of the second region is, for example, 10 ⁇ m or more and 15 ⁇ m or less.
  • the difference between the height of the first region R1 and the height of R3 of the third region is, for example, 2 ⁇ m or more and 8 ⁇ m or less, for example, 5 ⁇ m.
  • each region R1 to R4 can be confirmed by measuring the shape of the main surface 11a using, for example, a coordinate measuring machine.
  • the second region R2 is lower than the first region R1 and can be confirmed as a frame-shaped region surrounding the first region R1. Since the external electrodes 13 and 15 have a shape along the shape of the main surface 11a as described above, when the external electrodes 13 and 15 are formed in the first region R1, from the measurement result of the coordinate measuring machine.
  • the shape obtained by subtracting the thickness (for example, the average thickness) of the external electrodes 13 and 15 may be simply treated as the shape of the first region R1.
  • the roughness (Ra) of the first region R1 is larger than the roughness (Ra) of the third region R3.
  • the roughness (Ra) of the second region R2 is smaller than the roughness (Ra) of the third region R3.
  • the roughness (Ra) of the fourth region R4 is equal to the roughness (Ra) of the second region R2.
  • the roughness (Ra) of the main surface 11b is equal to the roughness (Ra) of the third region R3.
  • the roughness (Ra) of the first region R1 is, for example, 2.2 ⁇ m or more and 2.8 ⁇ m or less.
  • the roughness (Ra) of the third region R3 is, for example, 1.2 ⁇ m or more and 1.8 ⁇ m or less.
  • the roughness (Ra) of the second region R2, the fourth region R4, and the main surface 11b is, for example, 0.9 ⁇ m or more and 1.5 ⁇ m or less.
  • FIG. 7 is a sectional view showing a state in which a wiring member is connected to the piezoelectric element of FIG. As shown in FIG. 7, the wiring member 50 is connected to the piezoelectric element 10.
  • the wiring member 50 is, for example, a flexible printed circuit board (FPC) or a flexible flat cable (FFC).
  • the wiring member 50 is electrically connected to the external electrodes 13 and 15.
  • the wiring member 50 includes a strip-shaped base 51 and a pair of conductor layers 53 and 55.
  • the base 51 is, for example, a resin layer made of a resin such as a polyimide resin and having an electrical insulation property.
  • Each conductor layer 53, 55 is joined to the main surface of the base 51.
  • Each conductor layer 53, 55 is made of Cu, for example.
  • Each of the conductor layers 53 and 55 may have a configuration in which a Ni plating layer and an Au plating layer are provided in this order on a Cu layer.
  • the conductor layer 53 and the conductor layer 55 are arranged apart from each other.
  • the wiring member 50 is arranged on the main surface 11a so that the conductor layers 53 and 55 face the external electrodes 13 and 15, respectively.
  • the wiring member 50 is joined to the main surface 11a by the joining member 61.
  • the joining member 61 When viewed from the first direction D1, the joining member 61 includes the entire pair of first regions R1 shown in FIG. 4 and the pair of second regions R2 and third regions arranged between the pair of first regions R1. It covers at least part of R3.
  • the joining member 61 is a resin layer containing a plurality of conductive particles (not shown).
  • the conductive particles are, for example, metal particles and gold plated particles.
  • the joining member 61 contains, for example, a thermosetting elastomer.
  • the joining member 61 is formed by curing an anisotropic conductive paste or an anisotropic conductive film, for example.
  • the joining member 61 electrically connects the conductor layers 53 and 55 to the external electrodes 13 and 15, respectively.
  • the wiring member 50 is also joined to the main surface 11a by the joining member 62.
  • the joining member 62 does not contain a conductive filler and has electrical insulation.
  • the joining member 62 is arranged along one short side of the main surface 11a.
  • the joining member 62 joins the entire wiring member 50 in the width direction (second direction D2) to the main surface 11a.
  • the joining member 62 is separated from the joining member 61 in the third direction D3.
  • the joining member 62 contains, for example, nitrile rubber.
  • the joining member 62 may include the same resin material as the resin material included in the joining member 61.
  • the height of the first region R1 is higher than the height of the second region R2 surrounding the first region R1. Since the external electrodes 13 and 15 are arranged in the first region R1, the external electrodes 13 and 15 are in a state of protruding from the surrounding second region R2. If the external electrodes 13 and 15 are recessed from the surrounding second region R2, the wiring member 50 is blocked by the second region R2 and the bonding strength of the wiring member 50 to the external electrodes 13 and 15 is increased. It is difficult to increase easily. On the other hand, in the piezoelectric element 10, the bonding strength of the wiring member 50 to the external electrodes 13 and 15 can be easily increased.
  • the connection reliability between the external electrodes 13 and 15 and the wiring member 50 can be improved. Since a strip-shaped wiring member such as FPC or FFC is used as the wiring member 50, the wiring member 50 is smoothly deformed along the undulations of the main surface 11a reflected on the outer surfaces of the external electrodes 13 and 15. .. Thereby, the adhesion between the wiring member 50 and the external electrodes 13 and 15 is further improved.
  • a strip-shaped wiring member such as FPC or FFC
  • the height of the third region R3 is lower than the height of the first region R1. Therefore, the external electrodes 13 and 15 are in a state of protruding also from the third region R3. Therefore, the wiring member 50 is less likely to be hindered by the third region R3 (particularly, the portion arranged between the pair of first regions R1). Therefore, the connection reliability between the external electrodes 13 and 15 and the wiring member 50 can be further improved.
  • the roughness (Ra) of the first region R1 is larger than the roughness (Ra) of the third region R3. Therefore, the bonding strength between the external electrodes 13 and 15 and the first region R1 is improved. As a result, the connection reliability between the external electrodes 13 and 15 and the wiring member 50 can be further improved.
  • the swell of the main surface 11a is larger than that of the main surface 11b.
  • the waviness is, for example, the average length (RSm) of the roughness curve elements in the long side direction (third direction D3) of the main surface 11a, and the main surface 11a extends along the third direction D3. This is the surface where the mountains and valleys are formed. As a result, the main surface 11a easily expands and contracts in the third direction D3, so that bending vibration of the piezoelectric element 10 is less likely to be hindered.
  • a piezoelectric element corresponding to the embodiment was produced, and the roughness (Ra) of the external electrode, the second region, and the third region was measured.
  • the element body was formed such that the size of the main surface was 20 mm ⁇ 10 mm and the thickness was 500 ⁇ m.
  • the material of the element body was a piezoelectric element body containing PZT as a main component and PZN[Pb(Zn,Nb)O 3 ] added at 12.8%.
  • the external electrode was formed with a thickness of 2.0 ⁇ m.
  • the material of the electrode layers, the connection conductors, and the via conductors that form the external electrodes and the internal electrodes was AgPd alloy (ratio 95:5).
  • the roughness (Ra) of each region was measured according to JIS-B0601 (2001) using a three-dimensional measuring machine (Keyence VK-X250). 15 lines were measured with the measurement direction being the long side direction (third direction) of the main surface.
  • FIG. 8A is a graph showing a measurement cross-section curve of the external electrode.
  • the roughness (Ra) of the external electrode was 2.449 ⁇ m. Since the external electrode has a shape along the shape of the main surface on which the external electrode is formed, the roughness of the external electrode reflects the roughness of the first region.
  • FIG.8(b) is a graph which shows the measurement sectional curve of a 2nd area
  • 8C is a graph showing the measurement sectional curve of the third region.
  • a position outside the outer edge of the second region by about 200 ⁇ m was measured along the outer edge of the second region.
  • the roughness (Ra) of the third region was 1.577 ⁇ m.
  • the position where the height position (the position in the first direction) is the lowest is shown as 0 on the vertical axis. 8A to 8C, the inclination of the reference surface, noise, defects, and waviness components are corrected.
  • the height of the first region R1 may be at least higher than the height of the second region R2, and may be lower than the heights of the third region R3 and the fourth region R4.
  • the external electrodes 13 and 15 only need to be arranged in the first region R1, and the outer edge of the first region R1 may match the outer edge of the external electrodes 13 and 15 when viewed from the first direction D1.
  • the outer edge of the first region R1 may be located inside the outer edge of the external electrodes 13 and 15 when viewed from the first direction D1. That is, the external electrodes 13 and 15 may protrude from the outer edge of the first region R1 and be arranged in the second region R2, or the second region R2 and the third region.
  • the width of the second region R2 may be different depending on the circumferential position of the second region R2.

Landscapes

  • General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)
  • Particle Formation And Scattering Control In Inkjet Printers (AREA)

Abstract

L'invention concerne un élément piézoélectrique comprenant un corps d'élément , une électrode interne et une électrode externe. Le corps d'électrode présente une première surface principale et une seconde surface principale se faisant face. L'électrode interne est disposée dans le corps d'élément. L'électrode externe est disposée sur la première surface principale. La première surface principale comprend une première région et une seconde région. L'électrode externe est disposée dans la première région. La seconde région a une forme de cadre, et entoure la première région. Lorsque la seconde surface principale est définie comme surface de référence, la hauteur de la première région à partir de la surface de référence est supérieure à la hauteur de la seconde région à partir de la surface de référence.
PCT/JP2020/001688 2019-01-25 2020-01-20 Élément piézoélectrique WO2020153289A1 (fr)

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JP2019011066A JP7010247B2 (ja) 2019-01-25 2019-01-25 圧電素子

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JP2000028595A (ja) * 1998-07-10 2000-01-28 Olympus Optical Co Ltd 圧電構造体の製造方法および複合圧電振動子
JP2014053480A (ja) * 2012-09-07 2014-03-20 Ricoh Co Ltd 圧電体薄膜素子およびその製造方法、並びにこれを用いた圧電アクチュエータ、液滴吐出ヘッド及び液滴吐出装置
JP2015216190A (ja) * 2014-05-09 2015-12-03 スタンレー電気株式会社 圧電アクチュエータ及びその製造方法
JP2016186965A (ja) * 2015-03-27 2016-10-27 パナソニックＩｐマネジメント株式会社 圧電素子および圧電素子の製造方法
JP2018152541A (ja) * 2017-02-13 2018-09-27 Tdk株式会社 振動デバイス

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JP2015109415A (ja) 2013-10-24 2015-06-11 株式会社村田製作所 積層セラミック電子部品、テーピング電子部品連及び積層セラミック電子部品の製造方法
JP6560487B2 (ja) 2014-09-03 2019-08-14 ローム株式会社 インクジェットヘッド

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000028595A (ja) * 1998-07-10 2000-01-28 Olympus Optical Co Ltd 圧電構造体の製造方法および複合圧電振動子
JP2014053480A (ja) * 2012-09-07 2014-03-20 Ricoh Co Ltd 圧電体薄膜素子およびその製造方法、並びにこれを用いた圧電アクチュエータ、液滴吐出ヘッド及び液滴吐出装置
JP2015216190A (ja) * 2014-05-09 2015-12-03 スタンレー電気株式会社 圧電アクチュエータ及びその製造方法
JP2016186965A (ja) * 2015-03-27 2016-10-27 パナソニックＩｐマネジメント株式会社 圧電素子および圧電素子の製造方法
JP2018152541A (ja) * 2017-02-13 2018-09-27 Tdk株式会社 振動デバイス

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