WO2022181113A1 - 圧電素子及び圧電デバイス - Google Patents

圧電素子及び圧電デバイス Download PDF

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Publication number
WO2022181113A1
WO2022181113A1 PCT/JP2022/001322 JP2022001322W WO2022181113A1 WO 2022181113 A1 WO2022181113 A1 WO 2022181113A1 JP 2022001322 W JP2022001322 W JP 2022001322W WO 2022181113 A1 WO2022181113 A1 WO 2022181113A1
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WIPO (PCT)
Prior art keywords
pair
holding
piezoelectric element
electrodes
mounting
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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
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PCT/JP2022/001322
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English (en)
French (fr)
Japanese (ja)
Inventor
智紀 村山
隼人 田中
斉師 吉田
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Kyocera Corp
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Kyocera Corp
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Priority to JP2023502161A priority Critical patent/JPWO2022181113A1/ja
Priority to CN202280015654.4A priority patent/CN116868507A/zh
Publication of WO2022181113A1 publication Critical patent/WO2022181113A1/ja
Priority to US18/450,827 priority patent/US20230402994A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
    • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
    • H03H9/19—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator consisting of quartz
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02157—Dimensional parameters, e.g. ratio between two dimension parameters, length, width or thickness
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/05—Holders or supports
    • H03H9/0504—Holders or supports for bulk acoustic wave devices
    • H03H9/0509—Holders or supports for bulk acoustic wave devices consisting of adhesive elements
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/05—Holders or supports
    • H03H9/10—Mounting in enclosures
    • H03H9/1007—Mounting in enclosures for bulk acoustic wave [BAW] devices
    • H03H9/1014—Mounting in enclosures for bulk acoustic wave [BAW] devices the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the BAW device
    • H03H9/1021—Mounting in enclosures for bulk acoustic wave [BAW] devices the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the BAW device the BAW device being of the cantilever type
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
    • H03H9/132—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials characterized by a particular shape

Definitions

  • the present disclosure relates to a piezoelectric element and a piezoelectric device including the piezoelectric element.
  • piezoelectric devices include crystal resonators and crystal oscillators.
  • a thickness-shear vibration mode piezoelectric element As a type of piezoelectric element, a thickness-shear vibration mode piezoelectric element is known (for example, Patent Document 1).
  • This piezoelectric element is an AT-cut crystal piece on which excitation electrodes made of metal film patterns are formed on both main surfaces. In this piezoelectric element, when an alternating voltage is applied to the excitation electrodes, a portion of the crystal piece sandwiched between the excitation electrodes undergoes thickness-shear vibration.
  • Piezoelectric devices utilize the piezoelectric effect and inverse piezoelectric effect of piezoelectric elements to generate a specific oscillation frequency.
  • a typical piezoelectric device has a structure in which a piezoelectric element is accommodated in a package and hermetically sealed with a lid.
  • the piezoelectric element according to the present disclosure is a vibrating portion having a substantially rectangular shape in plan view and having a pair of main vibrating surfaces; a holding portion that is thicker than the vibrating portion, is integrated along at least one side of the vibrating portion in plan view, and has a pair of main holding surfaces; a pair of excitation electrodes located on the pair of vibration principal surfaces; a pair of mounting electrodes positioned on the pair of holding main surfaces; a pair of wiring electrodes electrically connecting the pair of excitation electrodes and the pair of mounting electrodes; with one of the pair of vibration principal surfaces and one of the pair of holding principal surfaces are on the same plane; the other of the pair of holding principal surfaces has a fixing portion in contact with the element mounting member;
  • the pair of mounting electrodes are positioned side by side at the fixed portion, Regarding each of the pair of mounting electrodes and the pair of wiring electrodes, when peripheral edges that are inside each other are defined as inner sides, The inner side of the mounting electrode and the inner side of the wiring electrode are linearly connected.
  • a piezoelectric device includes: a piezoelectric element according to the present disclosure; an element mounting member on which the piezoelectric element is positioned; a lid that hermetically seals the piezoelectric element together with the element mounting member; is provided.
  • FIG. 2 is a plan view showing the piezoelectric element of Embodiment 1.
  • FIG. FIG. 1B is a plan view of the piezoelectric element of FIG. 1A seen through from the back side;
  • FIG. 1B is a cross-sectional view taken along line Ic-Ic in FIG. 1A.
  • 1 is a perspective view showing a piezoelectric element of Embodiment 1.
  • FIG. 8 is a plan view showing a piezoelectric element of Embodiment 2;
  • FIG. 3B is a plan view of the piezoelectric element of FIG. 3A seen through from the back side;
  • FIG. 3B is a cross-sectional view taken along line IIIc-IIIc in FIG. 3A.
  • FIG. 11 is a plan view showing a first example of a piezoelectric element of Embodiment 3;
  • FIG. 11 is a plan view showing a second example of the piezoelectric element of Embodiment 3;
  • FIG. 11 is a plan view showing a third example of the piezoelectric element of Embodiment 3;
  • FIG. 11 is a plan view showing a fourth example of the piezoelectric element of Embodiment 3;
  • FIG. 12 is a plan view showing a fifth example of the piezoelectric element of Embodiment 3;
  • FIG. 11 is a plan view showing a sixth example of the piezoelectric element of Embodiment 3;
  • FIG. 11 is a plan view showing a seventh example of the piezoelectric element of Embodiment 3;
  • FIG. 11 is a plan view showing a seventh example of the piezoelectric element of Embodiment 3;
  • FIG. 11 is a plan view showing a seventh example of the piezoelectric element of
  • FIG. 11 is a plan view showing an eighth example of the piezoelectric element of Embodiment 3;
  • FIG. 12 is a plan view showing a ninth example of the piezoelectric element of Embodiment 3;
  • FIG. 11 is a perspective view showing a piezoelectric device of Embodiment 4;
  • FIG. 5B is a sectional view taken along line Vb-Vb in FIG. 5A;
  • FIG. 12 is a perspective view showing a part of the piezoelectric device of Embodiment 5;
  • 4 is a schematic plan view showing a first example of a holding portion in Embodiment 1.
  • FIG. 4 is a schematic plan view showing a second example of a holding portion in Embodiment 1.
  • FIG. 10 is a schematic plan view showing a third example of a holding portion according to Embodiment 1;
  • FIG. 10 is a schematic plan view showing a fourth example of a holding portion according to Embodiment 1;
  • FIG. 4 is a plan view showing a piezoelectric element of a comparative example;
  • FIG. 7B is a plan view seen through the back side of the piezoelectric element of FIG. 7A;
  • FIG. 7B is a cross-sectional view taken along line VIIc-VIIc in FIG. 7A;
  • FIG. 4 is a perspective view showing a piezoelectric element of a comparative example;
  • FIG. 1A is a plan view showing the piezoelectric element of Embodiment 1
  • FIG. 1B is a plan view of the piezoelectric element of FIG. 1A seen through from the back side
  • FIG. 1C is a cross-sectional view taken along line Ic-Ic in FIG. 1A
  • FIG. 2 is a perspective view showing the piezoelectric element of Embodiment 1.
  • the first embodiment relates to a piezoelectric element.
  • a pair of surfaces having a front-back relationship is defined as "principal surfaces”
  • a surface sandwiched between the pair of principal surfaces is defined as “side surfaces”
  • a dimension in the direction perpendicular to the principal surfaces is defined as "thickness”.
  • an orthogonal coordinate system XYZ consisting of X, Y and Z axes, which are the crystal axes of crystal, is rotated around the X axis by 30° or more and 50° or less to define an orthogonal coordinate system XY'Z'.
  • the "width" of an electrode is the dimension of the electrode in the direction perpendicular to the current flow when viewed in plan.
  • the piezoelectric element 10 of the first embodiment has a substantially rectangular shape in plan view, and includes a vibrating portion 11 having a pair of main vibration surfaces 111 and 112, and a vibrating portion 11 thicker than the vibrating portion 11 and having a thickness of the vibrating portion 11 in plan view.
  • a pair of mounting electrodes 151 and 152 are positioned side by side on the fixed portion 130 . Inner sides of the pair of mounting electrodes 151 and 152 and the pair of wiring electrodes 161 and 162 are defined as inner sides.
  • FIG. 1A the inner side 151a of the mounting electrode 151 and the inner side 161a of the wiring electrode 161 are connected linearly.
  • FIG. 1B the inner side 152a of the mounting electrode 152 and the inner side 162a of the wiring electrode 162 are connected linearly.
  • the wiring electrodes 161 and 162 are dotted for clarity.
  • Each of the above components may be configured as follows. Inner sides 151a and 152a of the mounting electrodes 151 and 152 extend linearly from the vibrating portion 11 side to the peripheral end (holding side surface 135) of the holding portion 13. As shown in FIG. The holding portion 13 further has a pair of holding side surfaces 133 and 134 sandwiched between the pair of holding main surfaces 131 and 132 .
  • One of the pair of mounting electrodes 151 and 152 (mounting electrode 151) extends from one of the pair of holding main surfaces 131 and 132 (holding main surface 131) through one of the pair of holding side surfaces 133 and 134 (holding side surface 133). It extends to the other (holding main surface 132) of the holding main surfaces 131, 132 of.
  • the other of the pair of mounting electrodes 151 and 152 extends from one of the pair of holding main surfaces 131 and 132 (holding main surface 131) through the other of the pair of holding side surfaces 133 and 134 (holding side surface 134). It extends to the other (holding main surface 132) of the holding main surfaces 131, 132 of.
  • the planar shape of the vibrating portion 11 is substantially rectangular.
  • the "substantially quadrangular” includes squares, rectangles (rectangles), rectangles with rounded corners, and the like.
  • the vibrating main surface 111 and the holding main surface 131 are on the same plane, and the thickness of the holding portion 13 is greater than the thickness of the vibrating portion 11 .
  • the holding part 13 has two holding sides 133, 134 along the XY' plane and one holding side 135 along the Y'Z' plane.
  • the inclined portion 12 having inclined main surfaces 121 and 122 and inclined side surfaces 123 and 124 is positioned between the vibrating portion 11 and the holding portion 13 .
  • the inclined main surface 121 is on the same plane as the vibrating main surface 111 and the holding main surface 131
  • the inclined main surface 122 is a slope so as to connect the vibrating main surface 112 and the holding main surface 132 .
  • a through hole 17 is formed in the inclined portion 12 so as to extend through the main inclined surfaces 121 and 122 in the thickness direction.
  • the inclined main surface 122 is formed by wet etching if the crystal axis of the crystal piece 18 is set as shown.
  • the mounting electrodes 151 and 152 are positioned on the main holding surface 132 having the fixing portion 130 (FIG. 1B).
  • the holding portion 13 may surround not only one side 116 (FIG. 1A) of the vibrating portion 11 but also two sides, three sides, or all sides of the vibrating portion 11 . Specific examples thereof will be described with reference to FIGS. 6A to 6D.
  • the holding portion 13a of the first example shown in FIG. 6A has a substantially I-shaped planar shape and is located on the first side 117a side of the vibrating portion 11, as in the first embodiment.
  • the holding portion 13c of the third example shown in FIG. 6C has a substantially U-shaped planar shape and is positioned on the first side 117a side, the second side 117b side, and the third side 117c side of the vibrating portion 11 .
  • the holding portion 13d of the fourth example shown in FIG. 6D has a substantially square-shaped planar shape, and the first side 117a side, the second side 117b side, the third side 117c side, and the fourth side 117d side of the vibrating portion 11.
  • the thickness of the holding portions 13a, 13b, 13c, and 13d is greater than the thickness of the vibrating portion 11.
  • the fixing portions 130 of the holding portions 13a, 13b, 13c, and 13d are all at the same position, but may be at different positions. That is, the fixing portion 130 may be located at any position on each of the holding portions 13a, 13b, 13c, and 13d.
  • the piezoelectric element 10 operates in a thickness-shear vibration mode, and has an oscillation frequency (fundamental wave) of, for example, 100 MHz or higher.
  • the vibrating portion 11 , the inclined portion 12 and the holding portion 13 are composed of one crystal piece 18 .
  • the excitation electrodes 141, 142, the mounting electrodes 151, 152, and the wiring electrodes 161, 162 are made of metal patterns of the same material.
  • the crystal piece 18 is an AT-cut crystal plate. That is, in crystal, the orthogonal coordinate system XYZ consisting of the X-axis (electrical axis), Y-axis (mechanical axis), and Z-axis (optical axis) is 30° or more and 50° or less (for example, 35° 15')
  • XY'Z' is defined by rotation
  • a wafer cut out parallel to the XZ' plane becomes the raw material of the crystal piece 18.
  • the longitudinal direction of the crystal piece 18 is parallel to the X-axis
  • the lateral direction is parallel to the Z'-axis
  • the thickness direction is parallel to the Y'-axis.
  • the crystal piece 18 has a length (X-axis direction) of 750-950 ⁇ m and a width (Z′-axis direction) of 600-800 ⁇ m.
  • the thickness (Y'-axis direction) of the holding portion 13 is 30 to 50 ⁇ m
  • the thickness (Y'-axis direction) of the vibrating portion 11 is approximately 5 to 10 ⁇ m
  • the excitation electrodes 141 and 142 have a side length of 250 to 400 ⁇ m.
  • the oscillation frequency at this time is approximately 160 to 340 MHz.
  • the inclined principal surface 121 is flush with the vibrating principal surface 111 and the holding principal surface 131 , but the inclined principal surface 122 is inclined so as to connect the vibrating principal surface 112 and the holding principal surface 132 . That is, the thickness of the inclined portion 12 becomes thinner as the distance from the holding portion 13 increases. Therefore, the stress transmitted from the holding portion 13 side to the vibrating portion 11 side is absorbed or dispersed by the inclined portion 12 (gentle step). Further, since the secondary vibration generated in the vibrating portion 11 is gradually attenuated toward the holding portion 13, the influence of the secondary vibration reflected by the holding portion 13 on the vibrating portion 11 is reduced. Therefore, the slope portion 12 also reduces the equivalent series resistance value.
  • the through hole 17 penetrates between the mounting electrodes 151 and 152 and the vibrating portion 11 in the thickness direction. Therefore, the stress transmitted from the holding portion 13 side to the vibrating portion 11 side is absorbed or dispersed by the through holes 17 . In other words, when the holding portion 13 is connected to the package, the distortion that occurs in the vibrating portion 11 can be reduced. Also, the through hole 17 functions to confine the vibration energy of the vibrating portion 11 . Therefore, the through holes 17 can also reduce the equivalent series resistance value. Furthermore, by forming the through hole 17 in the inclined portion 12, these effects are increased in conjunction with the action of the inclined portion 12. As shown in FIG.
  • the pair of excitation electrodes 141 and 142 are substantially rectangular in plan view, and are provided substantially at the centers of the main vibration surfaces 111 and 112 of the vibrating section 11, respectively.
  • Wiring electrodes 161 and 162 for connection that do not contribute to excitation extend from the excitation electrodes 141 and 142 to mounting electrodes 151 and 152 .
  • the excitation electrode 141 is electrically connected to the mounting electrode 151 via the wiring electrode 161
  • the excitation electrode 142 is electrically connected to the mounting electrode 152 via the wiring electrode 162 .
  • the mounting electrodes 151 are provided inside the holding main surfaces 131 and 132 , the holding side surfaces 133 and 135 , the inclined main surfaces 121 and 122 , the inclined side surface 123 and the through holes 17 .
  • the mounting electrodes 152 are provided inside the holding main surfaces 131 and 132 , the holding side surfaces 134 and 135 , the inclined main surfaces 121 and 122 , the inclined side surface 124 and the through holes 17 .
  • the excitation electrode 141 and the wiring electrode 161 are provided on the vibration main surface 111 side, and the excitation electrode 142 and the wiring electrode 162 are provided on the vibration main surface 112 side.
  • the metal patterns constituting the excitation electrodes 141, 142, the mounting electrodes 151, 152, and the wiring electrodes 161, 162 are, for example, a laminate of a base layer made of chromium (Cr) and a conductor layer made of gold (Au). is formed. That is, the base layer is positioned on the crystal piece 18, and the conductor layer is positioned on the base layer.
  • the underlayer mainly plays a role of obtaining adhesion to the crystal piece 18 .
  • the conductor layer mainly plays the role of obtaining electrical continuity.
  • Forming a metal film means forming a metal film.
  • the metal pattern manufacturing process includes a method of forming a photoresist pattern on a crystal piece and then etching it, and a method of forming a photoresist pattern on the crystal piece and then forming a film and then lifting off the film. or a method of forming a film by covering the crystal piece with a metal mask. Sputtering, vapor deposition, or the like is used for film formation.
  • the piezoelectric element 10 can be manufactured as follows using, for example, photolithography technology and etching technology.
  • a corrosion-resistant film is provided on the entire surface of an AT-cut crystal wafer, and a photoresist is provided on it. Subsequently, a mask having a pattern of the outline of the crystal piece 18 (including the through hole 17) and the vibrating portion 11 (only one side) is overlaid on the photoresist, and a part of the photoresist is exposed and developed. The corrosion resistant film is exposed and wet etching is performed on the corrosion resistant film in this state. Thereafter, the remaining corrosion-resistant film is used as a mask to wet-etch the crystal wafer, thereby forming the outer shape of the crystal piece 18 and the vibrating portion 11 . The outer shape of the crystal piece 18 is etched on both sides, and the vibrating portion 11 is etched on one side. The inclined main surface 122 is also formed by this wet etching.
  • the remaining corrosion-resistant film is removed from the crystal wafer, and a metal film that becomes the excitation electrodes 141, 142, etc. is provided on the entire surface of the crystal wafer.
  • a photoresist mask having a pattern of the excitation electrodes 141, 142 and the like is formed on the metal film, and unnecessary metal films are removed by etching to form the excitation electrodes 141 and 142 and the like.
  • a plurality of piezoelectric elements 10 are formed on the crystal wafer.
  • individual piezoelectric elements 10 are obtained by singulating the crystal wafer into individual piezoelectric elements 10 .
  • the operation of the piezoelectric element 10 is as follows. An alternating voltage is applied to the crystal piece 18 via the excitation electrodes 141 and 142 . Then, the crystal blank 18 causes thickness-shear vibration such that the vibration main surfaces 111 and 112 are shifted from each other, and generates a specific oscillation frequency. Thus, the piezoelectric element 10 utilizes the piezoelectric effect and the inverse piezoelectric effect of the crystal piece 18 to operate to output a signal with a constant oscillation frequency. At this time, the thinner the plate thickness of the crystal blank 18 (that is, the vibrating portion 11) between the excitation electrodes 141, 141, the higher the oscillation frequency.
  • the piezoelectric element 10 is suitable for higher frequencies and can reduce the equivalent series resistance value. The reason will be explained below.
  • the vibrating main surface 111 and the holding main surface 131 are on the same plane, and the thickness of the holding portion 13 is larger than the thickness of the vibrating portion 11 . Since the supporting structure can be realized, the mechanical strength of the piezoelectric element 10 can be maintained even if the vibrating portion 11 becomes thinner due to the higher oscillation frequency. Therefore, the piezoelectric element 10 has a structure suitable for high frequencies.
  • the piezoelectric element 50 of the comparative example shown in FIGS. 7A, 7B, 7C, and 8 and the piezoelectric element 10 of the first embodiment will be explained while being compared.
  • the piezoelectric element 50 of the comparative example has the same configuration as the piezoelectric element 10 of Embodiment 1, except that the mounting electrodes 551 and 552 and the wiring electrodes 561 and 562 have different shapes.
  • the inner side 551a of the mounting electrode 551 and the inner side 561a of the wiring electrode 561 are connected stepwise, and as shown in FIG. 7B, the inner side 552a of the mounting electrode 552 and the wiring electrode 562 and the inner side 562a are connected in a stepped manner. That is, the width 56w of the wiring electrodes 561 and 562 is narrowed. This is because if the width 56 w is increased, the wiring electrodes 561 and 562 may vibrate on the sides closer to the excitation electrodes 141 and 142 , and the vibration may leak to the holding portion 13 .
  • the inner side 151a of the mounting electrode 151 and the inner side 161a of the wiring electrode 161 are connected in a straight line
  • the inner side 152a of the mounting electrode 152 and the inner side 162a of the wiring electrode 162 are connected in a straight line.
  • the equivalent series resistance value is lowered by connecting and increasing the width 16w of the wiring electrodes 161 and 162 . Therefore, according to the piezoelectric element 10, the equivalent series resistance value can be reduced while being suitable for higher frequencies.
  • the inner sides 551a and 552a of the mounting electrodes 551 and 552 are stepped from the vibrating portion 11 side to the peripheral end (holding side surface 135) of the holding portion 13. extended. That is, the width 55w of the mounting electrodes 551 and 552 on the holding side surface 135 side is narrowed. This is because if the width 55w is increased, the mounting electrodes 551 and 552 are brought closer to each other, which may cause an electrical short circuit when the mounting electrodes 551 and 552 are connected to the element mounting member by the conductive adhesive. is.
  • the inner sides 151a and 152a of the mounting electrodes 151 and 152 are linearly extended from the vibrating portion 11 side to the peripheral edge (holding side surface 135) of the holding portion 13, so that the mounting electrodes 151 and 152 By increasing the width 15w on the holding side surface 135 side, the equivalent series resistance value can be further reduced.
  • the mounting electrodes 551 and 552 extend from the holding main surface 131 to the holding main surface 132 only through the holding side surface 135 .
  • the mounting electrodes 151 and 152 extend from the holding main surface 131 to the holding main surface 132 via the holding side surfaces 133 , 134 and 135 .
  • the mounting electrodes 151 , 152 cover not only the main holding surfaces 131 , 132 and the holding side surfaces 135 , but also the holding side surfaces 133 , 134 . Therefore, according to the first embodiment, the effective width of the mounting electrodes 151 and 152 can be increased more than in the comparative example, so the equivalent series resistance value can be further reduced.
  • FIG. 3A is a plan view showing the piezoelectric element of Embodiment 2
  • FIG. 3B is a plan view of the piezoelectric element of FIG. 3A seen through from the back side
  • FIG. 3C is a sectional view taken along line IIIc-IIIc in FIG. 3A.
  • the piezoelectric element 20 of Embodiment 2 has the same configuration as the piezoelectric element 10 of Embodiment 1 (FIGS. 1A and 1B), except that the wiring electrodes 261 and 262 have different shapes. In FIGS. 3A and 3B, the wiring electrodes 261 and 262 are dotted for clarity. Since FIG. 3B is not a bottom view of the back side of the piezoelectric element 20 but a plan view of the back side of the piezoelectric element 20 seen through from the front side, left and right are reversed in the following description.
  • the pair of excitation electrodes 141, 142 and the pair of mounting electrodes 151, 152 have a substantially rectangular shape with four sides in plan view.
  • the sides on the side of the holding portion 13 are defined as lower sides 141a and 142a
  • the sides facing the lower sides 141a and 142a are defined as upper sides 141b and 142b
  • the upper sides 141b and 142b are upward and the lower sides 141a and 142a are downward.
  • the sides on the vibrating portion 11 side are upper sides 151b and 152b.
  • the wiring electrode 261 extends from the lower side 141a of the excitation electrode 141 and one of the pair of side pieces (the right side 141d in the second embodiment) to the upper side 151b of the mounting electrode 151 .
  • the wiring electrode 262 extends from one of the lower side 142a and the pair of side pieces of the excitation electrode 142 (the right side 142d in the second embodiment) to the upper side 152b of the mounting electrode 152 .
  • the wiring electrodes 161 and 162 (FIGS. 1A and 1B) of the first embodiment are arranged from only the lower sides 141a and 142a (FIGS. 3A and 3B) of the excitation electrodes 141 and 142 to the upper sides 151b and 152b (FIGS. 3A and 3B) of the mounting electrodes 151 and 152. 3A and 3B).
  • the wiring electrodes 261 and 262 of the second embodiment are arranged not only from the lower sides 141a and 142a of the excitation electrodes 141 and 142 but also from the right sides 141d and 142d of the excitation electrodes 141 and 142 to the upper sides of the mounting electrodes 151 and 152.
  • the piezoelectric element 30 of Embodiment 3 is the same as that of Embodiment 1, except that the holding portion 13 has recesses (311 to 39) and part of the mounting electrodes 151 and 152 are positioned in the recesses (311 to 39). It has substantially the same configuration as the piezoelectric element 10 (FIGS. 1A and 1B).
  • the holding portion 13 has through holes 311 and 312 as recesses, and parts of the mounting electrodes 151 and 152 are positioned in the through holes 311 and 312, respectively.
  • the through holes 311 and 312 are circular in plan view, and the mounting electrodes 151 and 152 are partially cylindrically formed on the inner walls of the through holes 311 and 312, respectively. That is, the mounting electrode 151 is electrically connected between the main holding surface 131 side and the holding main surface 132 side through the through hole 311 , and the mounting electrode 152 is connected between the holding main surface 131 side and the holding main surface 132 side through the through hole 312 . is conducting. Therefore, according to the first example, since the resistance values of the mounting electrodes 151 and 152 can be reduced, the equivalent series resistance value of the piezoelectric element 30 can be further reduced. Either one of the through holes 311 and 312 may be provided.
  • the holding portion 13 has through holes 321 and 322 as recesses, and parts of the mounting electrodes 151 and 152 are positioned in the through holes 321 and 322, respectively.
  • the through holes 321 and 322 are elliptical in plan view, the long axes of the through holes 321 and 322 are aligned with the longitudinal direction of the piezoelectric element 30 , and the short axes of the through holes 321 and 322 are aligned with the short side direction of the piezoelectric element 30 . is consistent with Parts of the mounting electrodes 151 and 152 are formed in an elliptical cylindrical shape on the inner walls of the through holes 321 and 322, respectively.
  • the mounting electrode 151 is electrically connected between the main holding surface 131 side and the holding main surface 132 side through the through hole 321
  • the mounting electrode 152 is connected between the holding main surface 131 side and the holding main surface 132 side through the through hole 322 .
  • the holding portion 13 has through holes 331 and 332 as recesses, and parts of the mounting electrodes 151 and 152 are positioned in the through holes 331 and 332, respectively.
  • the through holes 331 and 332 are elliptical in plan view. The axis coincides with the longitudinal direction of the piezoelectric element 30 .
  • Parts of the mounting electrodes 151 and 152 are formed in an elliptical cylindrical shape on the inner walls of the through holes 331 and 332, respectively.
  • the mounting electrode 151 is electrically connected between the main holding surface 131 side and the holding main surface 132 side through the through hole 331
  • the mounting electrode 152 is connected between the holding main surface 131 side and the holding main surface 132 side through the through hole 332 .
  • the holding portion 13 has through holes 341a, 341b, 342a, and 342b as recesses, and the mounting electrodes 151 are partially positioned in the through holes 341a and 341b.
  • a portion of the mounting electrode 152 is located within 342b.
  • the through holes 341a, 341b, 342a, and 342b are circular in plan view, and a portion of the mounting electrode 151 is cylindrically formed on the inner wall of the through holes 341a and 341b, and the mounting electrode 151 is formed on the inner wall of the through holes 342a and 342b.
  • a part of the electrode 152 is formed in a cylindrical shape.
  • the mounting electrode 151 is electrically connected between the main holding surface 131 side and the holding main surface 132 side through the through holes 341a and 341b. , 342b. Therefore, according to the fourth example, since the resistance values of the mounting electrodes 151 and 152 can be reduced, the equivalent series resistance value of the piezoelectric element 30 can be further reduced. Either one of the through holes 341a and 341b and the through holes 342a and 342b may be used.
  • the holding portion 13 has cuts 351 and 352 as recesses, and parts of the mounting electrodes 151 and 152 are positioned in the cuts 351 and 352, respectively.
  • Notches 351 and 352 are formed in the holding side surface 135, and parts of the mounting electrodes 151 and 152 are formed in flat semi-cylindrical shapes on the inner walls of the notches 351 and 352, respectively.
  • the mounting electrode 151 is conductive between the main holding surface 131 side and the holding main surface 132 side through the cut 351
  • the mounting electrode 152 is conductive between the holding main surface 131 side and the holding main surface 132 side through the cut 352 . is doing. Therefore, according to the fifth example, since the resistance values of the mounting electrodes 151 and 152 can be reduced, the equivalent series resistance value of the piezoelectric element 30 can be further reduced. Either one of the cuts 351 and 352 may be used.
  • the holding portion 13 has notches 361 and 362 as recesses, and parts of the mounting electrodes 151 and 152 are positioned in the notches 361 and 362, respectively.
  • the notches 361 and 362 are formed in the holding side surfaces 133 and 134, respectively, and the inner walls of the notches 361 and 362 are formed with portions of the mounting electrodes 151 and 152, respectively, in a flat semi-cylindrical shape. That is, the mounting electrode 151 is conductive between the main holding surface 131 side and the holding main surface 132 side through the cut 361 , and the mounting electrode 152 is conductive between the holding main surface 131 side and the holding main surface 132 side through the cut 362 . is doing. Therefore, according to the sixth example, since the resistance values of the mounting electrodes 151 and 152 can be reduced, the equivalent series resistance value of the piezoelectric element 30 can be further reduced. Either one of the cuts 361 and 362 may be used.
  • the holding part 13 has a through hole 37 as a recess, and parts of the mounting electrodes 151 and 152 are positioned in the through hole 37, respectively.
  • the through-hole 37 has, for example, the same planar shape as the through-hole 17 , and a part of the mounting electrodes 151 and 152 is formed on the inner wall of the through-hole 37 . That is, the mounting electrodes 151 and 152 are electrically connected to the main holding surface 131 side and the holding main surface 132 side through the through holes 37 . Therefore, according to the seventh example, since the resistance values of the mounting electrodes 151 and 152 can be reduced, the equivalent series resistance value of the piezoelectric element 30 can be further reduced.
  • the holding portion 13 has a through hole 38 as a concave portion, and the mounting electrodes 151 and 152 are partially positioned in the through hole 38, and the through hole 17 in the seventh example and the like is has been removed.
  • the through-hole 38 is about twice as large as the through-hole 17 and is located near the inclined portion 12 of the holding portion 13 .
  • Parts of the mounting electrodes 151 and 152 are formed on the inner wall of the through hole 38 . That is, the mounting electrodes 151 and 152 are electrically connected to the main holding surface 131 side and the holding main surface 132 side through the through holes 38 . Therefore, according to the eighth example, since the resistance values of the mounting electrodes 151 and 152 can be reduced, the equivalent series resistance value of the piezoelectric element 30 can be further reduced.
  • the holding part 13 has a cut 39 as a recess, part of the mounting electrodes 151 and 152 are positioned in the cut 39, and the through hole 17 in the seventh example etc. is eliminated. ing.
  • the notch 39 is about the size of two through-holes 17 and is located from the retaining side 135 through the retaining portion 13 to the inclined portion 12 .
  • Parts of the mounting electrodes 151 and 152 are formed on the inner wall of the cut 39 .
  • the mounting electrodes 151 and 152 are electrically connected to the main holding surface 131 side and the holding main surface 132 side through the notch 39 . Therefore, according to the ninth example, since the resistance values of the mounting electrodes 151 and 152 can be reduced, the equivalent series resistance value of the piezoelectric element 30 can be further reduced.
  • the recesses (311-39) of the first to ninth examples are formed by wet etching, laser processing, ion beam processing, or the like, and there are no restrictions on the number, position and shape.
  • Other configurations, actions and effects of the third embodiment are the same as those of the first and second embodiments.
  • FIG. 5A is a perspective view showing the piezoelectric device of Embodiment 4
  • FIG. 5B is a cross-sectional view taken along line Vb-Vb in FIG. 5A. Description will be made below based on these figures.
  • the piezoelectric device 60 of Embodiment 4 includes the piezoelectric element 10 of Embodiment 1, a base 61 on which the piezoelectric element 10 is positioned, and hermetically seals the piezoelectric element 10 together with the base 61.
  • a lid 62 is provided.
  • the mounting electrodes 151 and 152 of the piezoelectric element 10 are connected to the substrate 61 by a conductive adhesive 61e.
  • the piezoelectric element 20 of the second embodiment may be used instead of the piezoelectric element 10 of the first embodiment.
  • the base 61 is also called an element mounting member or package, and consists of a substrate 61a and a frame 61b.
  • a space surrounded by the upper surface of the substrate 61 a , the inner surface of the frame 61 b , and the lower surface of the lid 62 serves as the housing portion 63 for the piezoelectric element 10 .
  • the piezoelectric element 10 outputs, for example, a reference signal used in electronic equipment or the like.
  • the piezoelectric device 60 includes a substrate 61a having a pair of electrode pads 61d on its upper surface and four external terminals 61c on its lower surface, a frame 61b positioned along the outer periphery of the upper surface of the substrate 61a, and a pair of electrode pads.
  • the piezoelectric element 10 is mounted on 61d via a conductive adhesive 61e, and the lid 62 hermetically seals the piezoelectric element 10 together with the frame 61b.
  • the substrate 61a and the frame 61b are made of a ceramic material such as alumina ceramics or glass ceramics, and integrally formed to form the base 61.
  • the base 61 and the lid 62 are substantially rectangular in plan view.
  • the external terminal 61c, the electrode pad 61d, and the lid 62 are electrically connected via a conductor formed inside or on the side surface of the base 61. As shown in FIG. Specifically, the external terminals 61c are positioned at the four corners of the lower surface of the substrate 61a. Two of these external terminals 61 c are electrically connected to the piezoelectric element 10 , and the remaining two external terminals 61 c are electrically connected to the lid 62 .
  • the external terminal 61c is used for mounting on a printed wiring board of an electronic device or the like.
  • the piezoelectric element 10 has the crystal piece 18 , the excitation electrode 141 formed on the upper surface of the crystal piece 18 , and the excitation electrode 142 formed on the lower surface of the crystal piece 18 , as described above.
  • the piezoelectric element 10 is bonded onto the electrode pad 61d via a conductive adhesive 61e, and plays a role of oscillating a reference signal for electronic equipment or the like by stable mechanical vibration and piezoelectric effect.
  • the electrode pads 61d are for mounting the piezoelectric element 10 on the substrate 61, and are positioned adjacent to each other along one side of the substrate 61a.
  • the pair of electrode pads 61d connects the mounting electrodes 151 and 152, respectively, and has one end of the piezoelectric element 10 as a fixed end, and the other end of the piezoelectric element 10 as a free end separated from the upper surface of the substrate 61a.
  • the piezoelectric element 10 is fixed on the substrate 61a with a cantilever support structure.
  • the conductive adhesive 61e is, for example, a binder such as silicone resin containing conductive powder as a conductive filler.
  • the lid body 62 is made of an alloy containing at least one of iron, nickel, and cobalt, for example, and is joined to the frame body 61b by seam welding or the like, so that the housing part 63 is in a vacuum state or filled with nitrogen gas or the like. hermetically sealed.
  • the piezoelectric device 60 is mounted on the surface of the printed circuit board that constitutes the electronic device by fixing the bottom surface of the external terminal 61c to the printed circuit board by soldering, gold (Au) bumps, conductive adhesive, or the like.
  • the piezoelectric device 60 is used as an oscillation source in various electronic devices such as smartphones, personal computers, clocks, game machines, communication devices, and in-vehicle devices such as car navigation systems.
  • the piezoelectric device 60 by including the piezoelectric element 10 having a low equivalent series resistance value, excellent electrical characteristics such as low power consumption and a high Q value can be exhibited.
  • a piezoelectric device having the piezoelectric element of the third embodiment will be described as a piezoelectric device of the fifth embodiment.
  • 5C is a perspective view showing part of the piezoelectric device of Embodiment 5. FIG. Description will be made below with reference to FIGS. 5C and 4F.
  • a piezoelectric device 70 of the fifth embodiment includes the piezoelectric element 30 of the sixth example of the third embodiment shown in FIG. It is different from the fourth embodiment in that Only the incision 361 is illustrated in FIG. 5C.
  • the introduction of the conductive adhesive 61e into the cuts 361 and 362 not only further reduces the equivalent series resistance of the piezoelectric element 30, but also increases the bonding area of the conductive adhesive 61e.
  • the bonding strength of the element 30 can be improved.
  • Other configurations, functions and effects of the fifth embodiment are the same as those of the fourth embodiment.
  • the piezoelectric device 70 is not limited to the piezoelectric element 30 of the sixth example of the third embodiment, and may include the piezoelectric element 30 of another example of the third embodiment.
  • the present disclosure has been described with reference to the above embodiments, the present disclosure is not limited to these.
  • the present disclosure also includes a combination of all or part of each embodiment.
  • Various changes that can be understood by those skilled in the art can be added to the configuration and details of the present disclosure.
  • the piezoelectric material may be lithium tantalate, lithium niobate, piezoelectric ceramics, or the like instead of quartz.
  • the present disclosure can be used as piezoelectric elements and piezoelectric devices.

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  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
PCT/JP2022/001322 2021-02-26 2022-01-17 圧電素子及び圧電デバイス Ceased WO2022181113A1 (ja)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011004425A (ja) * 2010-09-16 2011-01-06 Seiko Epson Corp 水晶振動片及び水晶デバイスの製造方法
JP2013102015A (ja) * 2011-11-08 2013-05-23 Seiko Epson Corp 電子デバイス、及び電子機器
JP2020136999A (ja) * 2019-02-22 2020-08-31 京セラ株式会社 水晶素子、水晶デバイス及び電子機器

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Publication number Priority date Publication date Assignee Title
JP2008236439A (ja) * 2007-03-21 2008-10-02 Epson Toyocom Corp 水晶振動片
JP5804825B2 (ja) * 2011-07-29 2015-11-04 京セラクリスタルデバイス株式会社 水晶振動素子及び水晶デバイス
JP6910134B2 (ja) * 2016-11-30 2021-07-28 京セラ株式会社 圧電振動素子及び圧電振動デバイス
JP7240250B2 (ja) * 2019-05-23 2023-03-15 京セラ株式会社 振動素子用圧電片、圧電振動素子及び圧電デバイス

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011004425A (ja) * 2010-09-16 2011-01-06 Seiko Epson Corp 水晶振動片及び水晶デバイスの製造方法
JP2013102015A (ja) * 2011-11-08 2013-05-23 Seiko Epson Corp 電子デバイス、及び電子機器
JP2020136999A (ja) * 2019-02-22 2020-08-31 京セラ株式会社 水晶素子、水晶デバイス及び電子機器

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