WO2022158028A1 - Piezoelectric vibrator - Google Patents

Piezoelectric vibrator Download PDF

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Publication number
WO2022158028A1
WO2022158028A1 PCT/JP2021/032789 JP2021032789W WO2022158028A1 WO 2022158028 A1 WO2022158028 A1 WO 2022158028A1 JP 2021032789 W JP2021032789 W JP 2021032789W WO 2022158028 A1 WO2022158028 A1 WO 2022158028A1
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WO
WIPO (PCT)
Prior art keywords
pair
excitation
piezoelectric
crystal
electrode
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PCT/JP2021/032789
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French (fr)
Japanese (ja)
Inventor
則夫 岩下
裕之 山本
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株式会社村田製作所
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Publication of WO2022158028A1 publication Critical patent/WO2022158028A1/en

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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 devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/05—Holders; Supports
    • H03H9/10—Mounting in enclosures
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; 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

Definitions

  • the present invention relates to piezoelectric vibrators.
  • Piezoelectric vibrators are used for various purposes such as timing devices, sensors, and oscillators in various electronic devices such as mobile communication terminals, communication base stations, and home appliances. Piezoelectric vibrators are incorporated into electronic components through reflow at high temperatures such as solder, but the frequency of the piezoelectric vibrator may fluctuate due to thermal stress or the like due to heating during reflow.
  • Patent Document 1 discloses a crystal blank having a flat plate portion provided with an excitation electrode and a first column portion provided with a connection electrode.
  • a crystal vibrating element is disclosed in which a through hole is provided in a crystal piece so as to be positioned at . According to the configuration of Patent Literature 1, by adopting such a configuration of the through holes, it is possible to reduce the influence of the first column portion on the thickness shear vibration, which is the main vibration.
  • the stress propagating from the connection portion to the excitation portion may not be sufficiently alleviated depending on, for example, the positional relationship of holding the conductive connection with respect to the through-hole. . Therefore, it may not be possible to sufficiently suppress frequency fluctuations.
  • the present invention has been made in view of such circumstances, and an object of the present invention is to provide a piezoelectric vibrator capable of suppressing frequency fluctuations.
  • a piezoelectric vibrator includes a piezoelectric piece, a pair of excitation electrodes provided on the piezoelectric piece and facing each other, and a pair of connection electrodes provided on the piezoelectric piece and electrically connected to the pair of excitation electrodes.
  • the pair of connection electrodes are arranged on the end side of the first direction in the first direction in a plan view of the piezoelectric piece and the second direction intersecting the first direction; and a pair of conductive holders for electrically connecting the pair of connecting electrodes of the piezoelectric vibrating element and the pair of electrode pads of the base member to hold the piezoelectric vibrating element above the base member.
  • the distance S1 between the portions of the portions that are most distant from each other in the second direction and the length L1 of the through hole in the second direction have a relationship of S1/L1 ⁇ 1.5.
  • FIG. 1 is an exploded perspective view schematically showing the configuration of a crystal resonator according to a first embodiment
  • FIG. 1 is a cross-sectional view schematically showing the configuration of a crystal resonator according to a first embodiment
  • FIG. 1 is a plan view schematically showing the configuration of a quartz resonator element according to a first embodiment
  • FIG. It is a graph which shows a stress change rate. It is a figure which shows stress distribution. It is a figure which shows stress distribution. It is a figure which shows stress distribution. It is a figure which shows stress distribution.
  • the X-axis, Y'-axis, and Z'-axis indicate an orthogonal coordinate system used to specify the structure of an AT-cut crystal, which is an example of a crystal piece.
  • the X-axis, Y'-axis and Z'-axis correspond to each other in each drawing.
  • the X-axis, Y'-axis, and Z'-axis are related to the crystallographic axes of the crystal piece 11, which will be described later.
  • the electric axis (polar axis) of the quartz crystal is the X-axis
  • the mechanical axis of the quartz crystal is the Y-axis
  • the optical axis of the quartz crystal is the Z-axis
  • the Y′-axis and Z′-axis correspond to the Y-axis and Z-axis, respectively, rotated about the X-axis from the Y-axis in the direction of the Z-axis by 35 degrees 15 minutes ⁇ 1 minute 30 seconds.
  • FIG. 1 is an exploded perspective view schematically showing the configuration of the crystal resonator according to the first embodiment.
  • FIG. 2 is a cross-sectional view schematically showing the configuration of the crystal resonator according to the first embodiment. 2 is a cross-sectional view of the crystal resonator 1 shown in FIG. 1 along line II-II.
  • a quartz crystal resonator unit 1 includes a quartz crystal resonator 10, a base member 30, a first conductive holding member 36a and a second conductive holding member which constitute a pair of conductive holding members.
  • a member 36b, a lid member 40, and a joint member 50 are provided.
  • the crystal oscillator 10 is provided between the base member 30 and the lid member 40 .
  • the base member 30 and the lid member 40 constitute a retainer for housing the crystal vibrating element 10 .
  • the crystal resonator element 10 is sealed, for example, in a vacuum state, but may be sealed in a state filled with an inert gas such as nitrogen or rare gas. In the example shown in FIGS.
  • the base member 30 has a flat plate shape, and the crystal vibrating element 10 is housed in the concave portion 49 of the lid member 40 .
  • the shapes of the base member 30 and the lid member 40 are not limited to the above, as long as at least the portion of the crystal vibrating element 10 to be excited is housed in the retainer.
  • the base member 30 may have a recess that accommodates at least part of the crystal vibrating element 10 on the lid member 40 side.
  • the crystal vibrating element 10 is an electromechanical energy conversion element capable of converting electrical energy and mechanical energy through the piezoelectric effect.
  • the crystal vibrating element 10 includes a flaky crystal element 11, a first excitation electrode 14a and a second excitation electrode 14b forming a pair of excitation electrodes, and a first extraction electrode forming a pair of extraction electrodes. 15a and a second extraction electrode 15b, and a first connection electrode 16a and a second connection electrode 16b forming a pair of connection electrodes.
  • the crystal piece 11 has an upper surface 11A and a lower surface 11B facing each other.
  • the upper surface 11A is located on the side opposite to the side facing the base member 30, that is, on the side facing the ceiling wall portion 41 of the lid member 40, which will be described later.
  • the lower surface 11B is located on the side facing the base member 30 .
  • the upper surface 11A and the lower surface 11B correspond to a pair of principal surfaces of the crystal piece 11. As shown in FIG.
  • the crystal piece 11 is, for example, an AT-cut crystal.
  • the AT-cut crystal piece has a plane parallel to the plane specified by the X-axis and Z'-axis (hereinafter referred to as "XZ' plane"; the same applies to planes specified by other axes).
  • the main surface is formed so that the direction parallel to the Y' axis becomes the thickness.
  • the outer edge of the crystal piece 11 is in a direction parallel to the X-axis (hereinafter referred to as “X-axis direction”; the same applies to directions parallel to other axes.). It has long sides that extend and short sides that extend in the Z′-axis direction.
  • the X-axis direction corresponds to an example of the "first direction”
  • the Z'-axis direction corresponds to an example of the "second direction”.
  • the crystal vibrating element 10 using the AT-cut crystal blank 11 has high frequency stability over a wide temperature range.
  • a thickness shear vibration mode is used as a main vibration.
  • a different cut other than the AT cut may be applied to the cut angle of the crystal piece 11 .
  • BT cut, GT cut, SC cut, etc. may be applied.
  • the crystal piece 11 When the upper surface 11A of the crystal piece 11 is viewed in plan, the crystal piece 11 has an excitation portion 17 where electromechanical energy conversion is performed, and a peripheral portion 18 positioned outside the excitation portion 17.
  • the excitation unit 17 is provided in a rectangular island shape and surrounded by a frame-shaped peripheral portion 18 .
  • the excitation section 17 has an upper surface 17A and a lower surface 17B, and the peripheral section 18 has an upper surface 18A and a lower surface 18B.
  • the upper surfaces 17A and 18A are part of the upper surface 11A of the crystal piece 11, and the lower surfaces 17B and 18B are parts of the lower surface 11B of the crystal piece 11.
  • the crystal piece 11 has a so-called mesa structure in which the excitation portion 17 is thicker than the peripheral portion 18 . According to the crystal piece 11 having the mesa structure in the excitation portion 17, vibration leakage of the crystal vibrating element 10 can be suppressed. Also, frequency fluctuation due to external stress can be suppressed.
  • the crystal piece 11 has a double-sided mesa structure, and excitation portions 17 protrude from a peripheral portion 18 on both sides of the upper surface 11A and the lower surface 11B.
  • a boundary region between the excitation portion 17 and the peripheral portion 18 has a tapered shape in which the thickness continuously changes. In other words, the surfaces connecting the upper surfaces 17A and 18A and the surfaces connecting the lower surfaces 17B and 18B of the excitation portion 17 and the peripheral portion 18 are uniformly inclined surfaces.
  • the excitation portion 17 and the peripheral section 18 are not limited to the above.
  • the excitation portion 17 and the peripheral portion 18 may each be formed in a strip shape over the entire width of the crystal piece 11 along the Z′-axis direction.
  • the boundary region between the excitation portion 17 and the peripheral portion 18 may have a stepped shape in which the change in thickness is discontinuous.
  • the boundary region may have a convex structure in which the amount of change in thickness changes continuously, or a bevel structure in which the amount of change in thickness changes discontinuously.
  • the crystal blank 11 may have a so-called inverted mesa structure in which the thickness of the excitation portion 17 is smaller than the thickness of the peripheral portion 18 .
  • the crystal piece 11 may have a flat plate shape in which the thickness of the excitation portion 17 and the thickness of the peripheral portion 18 are substantially equal.
  • the first excitation electrode 14 a and the second excitation electrode 14 b are provided in the central portion of the excitation section 17 .
  • the first excitation electrode 14 a is provided on the upper surface 17 A of the excitation section 17
  • the second excitation electrode 14 b is provided on the lower surface 17 B of the excitation section 17 .
  • the first excitation electrode 14 a and the second excitation electrode 14 b face each other with the excitation section 17 interposed therebetween, and are configured to be able to apply a voltage to the excitation section 17 .
  • the first extraction electrode 15 a and the second extraction electrode 15 b are provided from the excitation section 17 to the peripheral section 18 .
  • the first extraction electrode 15 a is connected to the first excitation electrode 14 a on the upper surface 17 A of the excitation section 17 and connected to the first connection electrode 16 a on the peripheral section 18 .
  • the second extraction electrode 15b is connected to the second excitation electrode 14b on the lower surface 17B of the excitation section 17 and to the second connection electrode 16b on the peripheral section 18 .
  • the first connection electrode 16a and the second connection electrode 16b are provided on the lower surface 18B of the peripheral portion 18.
  • the first connection electrode 16a and the second connection electrode 16b are arranged on the end (the short side of the crystal piece 11) in the X-axis direction when the upper surface 11A of the crystal piece 11 is viewed from above.
  • the first connection electrode 16a and the second connection electrode 16b are arranged in the negative direction of the X-axis (the direction opposite to the direction of the arrow) with respect to the first excitation electrode 14a and the second excitation electrode 14b in the peripheral portion 18. ) is provided in the region located on the side.
  • the first connection electrode 16a and the second connection electrode 16b are arranged in the Z'-axis direction, and the second connection electrode 16b is located on the negative side of the Z'-axis direction with respect to the first connection electrode 16a.
  • the first connection electrode 16a is electrically connected to the first excitation electrode 14a through the first extraction electrode 15a.
  • the second connection electrode 16b is electrically connected to the second excitation electrode 14b via the second extraction electrode 15b.
  • a through-hole 20 passing through the crystal piece 11 is formed in a region of the crystal piece 11 between the pair of excitation electrodes 14a and 14b and the pair of connection electrodes 16a and 16b.
  • the through hole 20 extends from the region between the first excitation electrode 14a and the first connection electrode 16a in the peripheral portion 18 to the region between the second excitation electrode 14b and the second connection electrode 16b. It extends axially.
  • the shape of the through hole 20 is, for example, a rectangular shape whose longitudinal direction is the Z'-axis direction.
  • the first excitation electrode 14a, the first extraction electrode 15a and the first connection electrode 16a are continuous and integrally formed.
  • the electrodes of these crystal vibrating elements 10 are conductive electrodes including, for example, a base layer made of a material with good adhesion to the crystal piece 11 and a surface layer made of a material with good chemical stability. It is a multilayer film.
  • the underlying layer is, for example, a chromium (Cr) layer, and the outermost layer is, for example, a gold (Au) layer.
  • the base member 30 includes a substrate 31, a first electrode pad 33a and a second electrode pad 33b forming a pair of electrode pads, a first through electrode 34a and a second through electrode 34b forming a pair of through electrodes, and a 1 external electrode 35a to fourth external electrode 35d.
  • the base 31 is a plate-like insulator having an upper surface 31A and a lower surface 31B.
  • the base 31 is, for example, a sintered material of insulating ceramic (alumina, etc.).
  • the substrate 31 is preferably made of a heat-resistant material.
  • the substrate 31 may be made of a material having a coefficient of thermal expansion close to that of the crystal piece 11. For example, it may be made of crystal.
  • the first electrode pad 33 a and the second electrode pad 33 b are provided on the upper surface 31 A of the base 31 .
  • the first electrode pad 33 a and the second electrode pad 33 b are terminals for electrically connecting the crystal vibrating element 10 to the base member 30 .
  • the first electrode pad 33a and the second electrode pad 33b are, for example, a conductive multilayer film including an Au layer on its surface.
  • the first through electrode 34a and the second through electrode 34b penetrate the base 31 in the Z'-axis direction.
  • the first through electrode 34a electrically connects the first electrode pad 33a and the first external electrode 35a.
  • the second through electrode 34b electrically connects the second electrode pad 33b and the second external electrode 35b.
  • the first to fourth external electrodes 35a to 35d are provided on the lower surface 31B of the substrate 31.
  • the first external electrode 35a and the second external electrode 35b are terminals for electrically connecting the crystal resonator 1 to an external substrate.
  • the third external electrode 35c and the fourth external electrode 35d are dummy electrodes to which, for example, electrical signals are not input/output. good.
  • the first conductive holding member 36a and the second conductive holding member 36b hold the crystal vibrating element 10 so that it can be excited.
  • the first conductive holding member 36 a and the second conductive holding member 36 b hold the crystal vibrating element 10 so that the excitation section 17 does not contact the base member 30 and the lid member 40 .
  • the first conductive holding member 36 a and the second conductive holding member 36 b electrically connect the crystal vibrating element 10 and the base member 30 .
  • the first conductive holding member 36a electrically connects the first electrode pad 33a and the first connection electrode 16a
  • the second conductive holding member 36b connects the second electrode pad 33b and the second connection electrode. 16b are electrically connected.
  • the main component of the first conductive holding member 36a and the second conductive holding member 36b is not limited to silicone resin as long as it is a curable resin, and may be, for example, epoxy resin or acrylic resin. Further, the conductivity of the first conductive holding member 36a and the second conductive holding member 36b is not limited to being imparted by silver particles, and may be imparted by other metals, conductive ceramics, conductive organic materials, and the like. may The main component of the first conductive holding member 36a and the second conductive holding member 36b may be a conductive polymer.
  • the lid member 40 and the base member 30 form an internal space that accommodates the crystal vibrating element 10 .
  • the lid member 40 has a recess 49 that opens toward the base member 30 , and the internal space in this embodiment corresponds to the space inside the recess 49 .
  • the lid member 40 has a flat top wall portion 41 and side wall portions 42 extending from the outer edge of the top wall portion 41 toward the base member 30 .
  • the recessed portion 49 of the lid member 40 is formed by the ceiling wall portion 41 and the side wall portion 42 .
  • the lid member 40 further has a flange portion 43 connected to the tip of the side wall portion 42 on the base member 30 side and extending outward along the upper surface 31A of the base 31 . When the upper surface 31 ⁇ /b>A of the base 31 is viewed from above, the flange portion 43 extends like a frame so as to surround the crystal vibrating element 10 .
  • the material of the lid member 40 is desirably a conductive material, more desirably a highly airtight metal material. Since the cover member 40 is made of a conductive material, the cover member 40 is provided with an electromagnetic shielding function that reduces the entry and exit of electromagnetic waves into the internal space. From the viewpoint of suppressing the generation of thermal stress, the material of the lid member 40 is desirably a material having a coefficient of thermal expansion close to that of the base 31. For example, the coefficient of thermal expansion near room temperature is glass or ceramic, which can be used over a wide temperature range. It is a matching Fe--Ni--Co based alloy.
  • the joint member 50 is provided over the entire perimeter of the base member 30 and the lid member 40 and has a rectangular frame shape.
  • the first electrode pads 33a and the second electrode pads 33b are arranged inside the bonding member 50, and the bonding member 50 is provided so as to surround the crystal vibrating element 10. ing.
  • the joining member 50 joins the base member 30 and the lid member 40 and seals the recess 49 corresponding to the internal space. Specifically, the joining member 50 joins the base 31 and the flange portion 43 .
  • the joining member 50 includes, for example, a metallized layer made of molybdenum (Mo) provided on the upper surface 31A of the base 31, and a gold-tin (Au—Sn)-based eutectic layer provided between the metallized layer and the flange portion 43. It is provided by a metal solder layer made of an alloy.
  • Mo molybdenum
  • Au—Sn gold-tin
  • the material of the bonding member 50 is not limited to the above, it preferably has low moisture permeability from the viewpoint of suppressing fluctuations in the frequency characteristics of the crystal oscillator 10, and more preferably has low gas permeability.
  • the joint member 50 in order to electrically connect the lid member 40 to the ground potential via the joint member 50, it is desirable that the joint member 50 has conductivity.
  • the base member 30 and the lid member 40 may be joined by seam welding.
  • FIG. 3 is a plan view schematically showing the configuration of the crystal oscillator according to the first embodiment.
  • FIG. 4 is a graph showing the stress change rate.
  • FIGS. 5-7 is a figure which shows stress distribution, respectively.
  • the dimensions (spacing S1, length L1, widths W1 and W2, diameter R1) of each part when the crystal resonator element 10 is viewed in plan will be described with reference to FIG.
  • the space S1 is the space between the edges of the first conductive holding member 36a and the second conductive holding member 36b, which are the farthest from each other in the Z' direction. More specifically, the edge portion of the first conductive holding member 36a located on the most positive side in the Z′-axis direction and the edge portion of the second conductive holding member 36b located on the most negative side in the Z′-axis direction. is the distance in the Z-axis direction between The length L1 is the length of the through-hole 20 in the Z' direction.
  • Width W1 is the width of crystal blank 11 in the Z′ direction. More specifically, between the edge portion of the crystal piece 11 located on the positive side of the excitation portion 17 in the Z′-axis direction and the edge portion of the crystal piece 11 located on the side of the excitation portion 17 in the negative Z′-axis direction. is the distance in the Z-axis direction. Width W2 is the width of excitation section 17 in the Z′ direction.
  • the outer edge of the boundary region between the excitation portion 17 and the peripheral portion 18 on the positive Z′-axis direction side, and the boundary between the peripheral portion 18 and the peripheral portion 18 on the positive Z′-axis direction side. is the distance between the outer edges in the boundary area between
  • the diameter R1 is the diameter of the first conductive retaining member 36a and the second conductive retaining member 36b.
  • the diameter of the first conductive holding member 36a may be different from the diameter of the second conductive holding member 36b.
  • the horizontal axis of the graph shown in FIG. 4 indicates the ratio of the interval S1 to the length L1, and the vertical axis indicates the stress change rate based on the stress when S1/L1 is the smallest.
  • the stress in this graph is the heat that propagates from the base member 30 to the crystal vibrating element 10 via the first conductive holding member 36a and the second conductive holding member 36b when the crystal oscillator 1 is reflow soldered to an external substrate. Calculated based on stress simulations.
  • Both the solid line and the broken line are integrals of the stress applied to the excitation part 17 in the crystal element 10 where the length in the X-axis direction of the crystal blank 11 is 0.76 mm, the width W1 is 0.68 mm, and the width W2 is 0.56 mm.
  • the solid line indicates the maximum stress of the excitation portion 17 at each S1/L1 when the length L1 is changed when the interval S1 is 0.37 mm. It shows how much it increased compared to the maximum stress of
  • the dashed line indicates the maximum stress of the excitation portion 17 at each S1/L1 when the length L1 is changed when the interval S1 is 0.61 mm. It shows how much it increased compared to the maximum stress of
  • the interval S1 and the length L1 desirably have a relationship of 0.6 ⁇ S1/L1. According to this, since the first conductive holding member 36a and the second conductive holding member 36b are separated sufficiently, the positions and sizes of the first conductive holding member 36a and the second conductive holding member 36b may vary due to manufacturing errors. Even if the voltage fluctuates, it is possible to suppress the occurrence of problems due to short-circuiting between the first conductive holding member 36a and the second conductive holding member 36b.
  • the interval S1 and the length L1 more preferably have a relationship of 0.8 ⁇ S1/L1. According to this, it is possible to further suppress the occurrence of problems due to short-circuiting between the first conductive holding member 36a and the second conductive holding member 36b.
  • the holding position of the crystal oscillator 10 is separated, the holding strength of the crystal oscillator 10 can be suppressed from being lowered, and the occurrence of problems due to damage such as dropout of the crystal oscillator 10 can be suppressed.
  • the length L1 and width W1 desirably have a relationship of 0.55 ⁇ L1/W1. According to this, when the interval S1 and the length L1 have a relationship of S1/L1 ⁇ 1.5, the interval S1 can be made sufficiently large because the length L1 is sufficiently large. Therefore, the first conductive holding member 36a and the second conductive holding member 36b are sufficiently spaced apart, and problems such as short-circuiting between the conductive holding members and damage to the crystal oscillator can be suppressed. Moreover, the length L1 and the width W1 desirably have a relationship of L1/W1 ⁇ 0.75.
  • the distance S1 and the radius R1 desirably have a relationship of 0.2 ⁇ S1/R1. According to this, the first conductive holding member 36a and the second conductive holding member 36b are sufficiently spaced apart, and it is possible to suppress the occurrence of problems such as short-circuiting between the conductive holding members and damage to the crystal oscillator.
  • the distance S1 and the radius R1 desirably have a relationship of S1/R1 ⁇ 0.35. According to this, problems caused by the miniaturization of the first conductive holding member 36a and the second conductive holding member 36b, such as a decrease in the holding strength of the crystal vibration element 10 and the base member 30 of the crystal vibration element 10 contact can be suppressed.
  • the configuration shown in FIG. 3 is an example that satisfies the above positional relationship and the like, and the dimensions of each part in FIG. not a thing
  • the interval S1 and the length L1 may have a relationship of L1 ⁇ S1 as long as they have a relationship of 0.8 ⁇ S1/L1 ⁇ 1.5.
  • the width W2, the length L1, and the interval S1 may have a relationship of W2 ⁇ L1, or may have a relationship of W2 ⁇ S1.
  • the crystal blank includes a pair of excitation electrodes provided on the crystal blank and facing each other, and a pair of connection electrodes provided on the crystal blank and electrically connected to the pair of excitation electrodes.
  • the pair of connection electrodes includes a crystal vibrating element and a pair of electrode pads, which are arranged on the end side of the first direction in the first direction and the second direction intersecting the first direction in plan view of the crystal piece.
  • a through hole penetrating through the crystal piece is provided in a region of the crystal piece between the pair of excitation electrodes and the pair of connection electrodes in the first direction;
  • the distance S1 between the portions that are most distant from each other in the second direction and the length L1 of the through hole in the second direction have a relationship of S1/L1 ⁇ 1.5. According to this, the influence of the thermal stress in the excitation part 17 can be suppressed. In particular, the smaller S1/L1 is, the more the stress change in the central portion of the excitation section 17 can be suppressed. Therefore, even if external stress such as reflow thermal stress propagates from the base member to the crystal vibrating element, the stress applied to the excitation section can be alleviated, so that frequency fluctuation can be suppressed.
  • the interval S1 and the length L1 have a relationship of 0.8 ⁇ S1/L1. According to this, since the pair of conductive holding members are sufficiently separated from each other, even if the positions and sizes of the pair of conductive holding members vary due to manufacturing errors, short-circuiting of the pair of conductive holding members will cause problems. can be suppressed. In addition, since the holding position of the crystal oscillator is separated, it is possible to suppress the deterioration of the holding strength of the crystal oscillator, thereby suppressing the occurrence of defects due to damage such as dropout of the crystal oscillator.
  • the width W1 and the length L1 of the crystal piece in the second direction have a relationship of 0.55 ⁇ L1/W1 ⁇ 0.75. If 0.55 ⁇ L1/W1, when the distance S1 and the length L1 have a relationship of S1/L1 ⁇ 1.5, the distance S1 is sufficiently large because the length L1 is sufficiently large. can. Therefore, the pair of conductive holding members are sufficiently spaced apart from each other, and problems such as a short circuit between the conductive holding members and damage to the crystal oscillator can be suppressed. If L1/W1 ⁇ 0.75, it is possible to suppress the deterioration of the mechanical strength of the crystal piece due to the presence of the through-holes, and to suppress the occurrence of problems due to damage to the crystal vibrating element. In addition, since the crystal pieces on both sides of the through-hole can have sufficient areas of the upper surface and the lower surface, it is possible to suppress the occurrence of problems such as disconnection due to narrowing of the pair of extraction electrodes.
  • the crystal piece has an excitation portion provided with a pair of excitation electrodes, and a peripheral portion that is thinner than the excitation portion and is located outside the excitation portion in plan view of the crystal piece, and the width of the excitation portion is W2 , the interval S1, the length L1, and the width W1 have a relationship of S1 ⁇ L1 ⁇ W1 ⁇ W2.
  • piezoelectric pieces suitably used in the piezoelectric vibrator according to this embodiment include, for example, piezoelectric ceramics such as lead zirconate titanate (PZT) and aluminum nitride, and piezoelectric single crystals such as lithium niobate and lithium tantalate. However, it is not limited to these and can be selected as appropriate.
  • the embodiments according to the present invention are applicable without any particular limitation, such as timing devices, sound generators, oscillators, load sensors, and the like, as long as they are devices that perform electromechanical energy conversion by the piezoelectric effect.

Abstract

This piezoelectric vibrator is provided with a piezoelectric vibration element (10), a base member (30), and a pair of electrically conductive holding members (36a, 36b) which electrically connect a pair of connecting electrodes (16a, 16b) of the piezoelectric vibration element (10) and a pair of electrode pads (33a, 33b) of the base member (30), and which hold the piezoelectric vibration element (10) above the base member (30), wherein: a through hole (20) penetrating through a piezoelectric piece (11) is provided in a region of the piezoelectric piece (11) between a pair of excitation electrodes (14a, 14b) and the pair of connecting electrodes (16a, 16b) in a first direction; and a separation S1 between the parts of the edge portions of each of the pair of electrically conductive holding members (36a, 36b) that are farthest apart from one another in a second direction and a length L1 of the through hole (20) in the second direction obey the relationship S1/L1≤1.5.

Description

圧電振動子piezoelectric vibrator
　本発明は、圧電振動子に関する。 The present invention relates to piezoelectric vibrators.
　移動通信端末、通信基地局、家電などの各種電子機器において、タイミングデバイス、センサ、発振器などの様々な用途に圧電振動子が用いられている。圧電振動子は、半田などの高温下のリフローを経て電子部品に組み込まれるが、リフローにおける加熱による熱応力等によって圧電振動子の周波数が変動してしまう場合がある。 Piezoelectric vibrators are used for various purposes such as timing devices, sensors, and oscillators in various electronic devices such as mobile communication terminals, communication base stations, and home appliances. Piezoelectric vibrators are incorporated into electronic components through reflow at high temperatures such as solder, but the frequency of the piezoelectric vibrator may fluctuate due to thermal stress or the like due to heating during reflow.
　圧電振動子の一例として、特許文献１には、励振電極が設けられた平板部と接続電極が設けられた第一柱部とを有する水晶片を備え、第一柱部と励振電極との間に位置するように水晶片に貫通穴が設けられた水晶振動素子が開示されている。特許文献１の構成によれば、このような貫通穴の構成を採用されることにより、第一柱部による主振動である厚みすべり振動への影響を低減させることができる。 As an example of a piezoelectric vibrator, Patent Document 1 discloses a crystal blank having a flat plate portion provided with an excitation electrode and a first column portion provided with a connection electrode. A crystal vibrating element is disclosed in which a through hole is provided in a crystal piece so as to be positioned at . According to the configuration of Patent Literature 1, by adopting such a configuration of the through holes, it is possible to reduce the influence of the first column portion on the thickness shear vibration, which is the main vibration.
特開２０１７－１７４３４号公報JP 2017-17434 A
　しかしながら、水晶片に貫通孔を設けた場合であっても、例えば、貫通孔に対する導電性接続保持の位置関係によっては接続部から励振部へ伝搬する応力を充分に緩和することができない場合がある。したがって周波数変動が十分に抑制することができないことがある。 However, even if the through-hole is provided in the crystal piece, the stress propagating from the connection portion to the excitation portion may not be sufficiently alleviated depending on, for example, the positional relationship of holding the conductive connection with respect to the through-hole. . Therefore, it may not be possible to sufficiently suppress frequency fluctuations.
　本発明はこのような事情に鑑みてなされたものであり、本発明の目的は、周波数変動が抑制可能な圧電振動子を提供することである。 The present invention has been made in view of such circumstances, and an object of the present invention is to provide a piezoelectric vibrator capable of suppressing frequency fluctuations.
　本発明の一態様に係る圧電振動子は、圧電片と、圧電片に設けられ互いに対向する一対の励振電極と、圧電片に設けられ一対の励振電極に電気的に接続された一対の接続電極とを有し、一対の接続電極は、圧電片の平面視における第１方向及び第１方向に交差する第２方向のうち第１方向の端部側に配置された、圧電振動素子と、一対の電極パッドを有するベース部材と、圧電振動素子の一対の接続電極とベース部材の一対の電極パッドとを電気的に接続し、ベース部材の上方に圧電振動素子を保持する、一対の導電性保持部材とを備え、第１方向における一対の励振電極と一対の接続電極との間の圧電片の領域には、圧電片を貫通する貫通孔が設けられ、一対の導電性保持部材のそれぞれの縁部のうち第２方向における互いに最も離間する部分同士の間の間隔Ｓ１と、貫通孔の第２方向における長さＬ１とは、Ｓ１／Ｌ１≦１．５の関係を有する。 A piezoelectric vibrator according to an aspect of the present invention includes a piezoelectric piece, a pair of excitation electrodes provided on the piezoelectric piece and facing each other, and a pair of connection electrodes provided on the piezoelectric piece and electrically connected to the pair of excitation electrodes. wherein the pair of connection electrodes are arranged on the end side of the first direction in the first direction in a plan view of the piezoelectric piece and the second direction intersecting the first direction; and a pair of conductive holders for electrically connecting the pair of connecting electrodes of the piezoelectric vibrating element and the pair of electrode pads of the base member to hold the piezoelectric vibrating element above the base member. and a through hole penetrating the piezoelectric piece is provided in a region of the piezoelectric piece between the pair of excitation electrodes and the pair of connection electrodes in the first direction, and the edge of each of the pair of conductive holding members is provided. The distance S1 between the portions of the portions that are most distant from each other in the second direction and the length L1 of the through hole in the second direction have a relationship of S1/L1≦1.5.
　本発明によれば、周波数変動が抑制可能な圧電振動子が提供できる。 According to the present invention, it is possible to provide a piezoelectric vibrator capable of suppressing frequency fluctuations.
第１実施形態に係る水晶振動子の構成を概略的に示す分解斜視図である。1 is an exploded perspective view schematically showing the configuration of a crystal resonator according to a first embodiment; FIG. 第１実施形態に係る水晶振動子の構成を概略的に示す断面図である。1 is a cross-sectional view schematically showing the configuration of a crystal resonator according to a first embodiment; FIG. 第１実施形態に係る水晶振動素子の構成を概略的に示す平面図である。1 is a plan view schematically showing the configuration of a quartz resonator element according to a first embodiment; FIG. 応力変化率を示すグラフである。It is a graph which shows a stress change rate. 応力分布を示す図である。It is a figure which shows stress distribution. 応力分布を示す図である。It is a figure which shows stress distribution. 応力分布を示す図である。It is a figure which shows stress distribution.
　以下、図面を参照しながら本発明の実施形態について説明する。各実施形態の図面は例示であり、各部の寸法や形状は模式的なものであり、本願発明の技術的範囲を当該実施形態に限定して解するべきではない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings of each embodiment are examples, and the dimensions and shapes of each part are schematic, and the technical scope of the present invention should not be construed as being limited to the embodiments.
　各々の図面には、各々の図面相互の関係を明確にし、各部材の位置関係を理解する助けとするために、便宜的にＸ軸、Ｙ’軸及びＺ’軸からなる直交座標系を付すことがある。Ｘ軸、Ｙ’軸及びＺ’軸は水晶片の一例であるＡＴカット型水晶の構造を特定するために用いられる直交座標系を示したものである。Ｘ軸、Ｙ’軸及びＺ’軸は各図面において互いに対応している。Ｘ軸、Ｙ’軸及びＺ’軸は、それぞれ、後述の水晶片１１の結晶軸（Ｃｒｙｓｔａｌｌｏｇｒａｐｈｉｃ　Ａｘｅｓ）に関係している。具体的には、水晶結晶の電気軸（極性軸）をＸ軸とし、水晶結晶の機械軸をＹ軸とし、水晶結晶の光学軸をＺ軸とする直交座標系において、Ｙ’軸及びＺ’軸は、それぞれ、Ｙ軸及びＺ軸をＸ軸の周りにＹ軸からＺ軸の方向に３５度１５分±１分３０秒回転させた軸に相当する。 An orthogonal coordinate system consisting of the X-axis, Y'-axis and Z'-axis is attached to each drawing for convenience in order to clarify the relationship between each drawing and to help understand the positional relationship of each member. Sometimes. The X-axis, Y'-axis, and Z'-axis indicate an orthogonal coordinate system used to specify the structure of an AT-cut crystal, which is an example of a crystal piece. The X-axis, Y'-axis and Z'-axis correspond to each other in each drawing. The X-axis, Y'-axis, and Z'-axis are related to the crystallographic axes of the crystal piece 11, which will be described later. Specifically, in an orthogonal coordinate system in which the electric axis (polar axis) of the quartz crystal is the X-axis, the mechanical axis of the quartz crystal is the Y-axis, and the optical axis of the quartz crystal is the Z-axis, the Y′-axis and Z′-axis The axes correspond to the Y-axis and Z-axis, respectively, rotated about the X-axis from the Y-axis in the direction of the Z-axis by 35 degrees 15 minutes±1 minute 30 seconds.
　＜第１実施形態＞
　まず、図１及び図２を参照しつつ、本発明の第１実施形態に係る水晶振動子１の概略構成について説明する。図１は、第１実施形態に係る水晶振動子の構成を概略的に示す分解斜視図である。図２は、第１実施形態に係る水晶振動子の構成を概略的に示す断面図である。なお、図２は、図１に示した水晶振動子１のＩＩ－ＩＩ線に沿った断面図である。 <First Embodiment>
First, referring to FIGS. 1 and 2, a schematic configuration of a crystal oscillator 1 according to a first embodiment of the present invention will be described. FIG. 1 is an exploded perspective view schematically showing the configuration of the crystal resonator according to the first embodiment. FIG. 2 is a cross-sectional view schematically showing the configuration of the crystal resonator according to the first embodiment. 2 is a cross-sectional view of the crystal resonator 1 shown in FIG. 1 along line II-II.
　水晶振動子（Ｑｕａｒｔｚ　Ｃｒｙｓｔａｌ　Ｒｅｓｏｎａｔｏｒ　Ｕｎｉｔ）１は、水晶振動素子（Ｑｕａｒｔｚ　Ｃｒｙｓｔａｌ　Ｒｅｓｏｎａｔｏｒ）１０と、ベース部材３０と、一対の導電性保持部材を構成する第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂと、蓋部材４０と、接合部材５０とを備えている。水晶振動素子１０は、ベース部材３０と蓋部材４０との間に設けられている。ベース部材３０及び蓋部材４０は、水晶振動素子１０を収容するための保持器を構成している。保持器の内部空間において、水晶振動素子１０は、例えば真空状態で封止されているが、窒素や希ガスなどの不活性ガスが充填された状態で封止されてもよい。図１及び図２に示した例では、ベース部材３０が平板状を成しており、蓋部材４０の凹部４９に水晶振動素子１０が収容されている。但し、水晶振動素子１０のうち少なくとも励振される部分が保持器に収容されれば、ベース部材３０及び蓋部材４０の形状は上記に限定されるものではない。例えば、ベース部材３０は、蓋部材４０の側に水晶振動素子１０の少なくとも一部を収容する凹部を有してもよい。 A quartz crystal resonator unit 1 includes a quartz crystal resonator 10, a base member 30, a first conductive holding member 36a and a second conductive holding member which constitute a pair of conductive holding members. A member 36b, a lid member 40, and a joint member 50 are provided. The crystal oscillator 10 is provided between the base member 30 and the lid member 40 . The base member 30 and the lid member 40 constitute a retainer for housing the crystal vibrating element 10 . In the inner space of the holder, the crystal resonator element 10 is sealed, for example, in a vacuum state, but may be sealed in a state filled with an inert gas such as nitrogen or rare gas. In the example shown in FIGS. 1 and 2 , the base member 30 has a flat plate shape, and the crystal vibrating element 10 is housed in the concave portion 49 of the lid member 40 . However, the shapes of the base member 30 and the lid member 40 are not limited to the above, as long as at least the portion of the crystal vibrating element 10 to be excited is housed in the retainer. For example, the base member 30 may have a recess that accommodates at least part of the crystal vibrating element 10 on the lid member 40 side.
　水晶振動素子１０は、圧電効果により電気エネルギーと機械エネルギーとに変換可能な電気機械エネルギー変換素子である。水晶振動素子１０は、薄片状の水晶片（Ｑｕａｒｔｚ　Ｃｒｙｓｔａｌ　Ｅｌｅｍｅｎｔ）１１と、一対の励振電極を構成する第１励振電極１４ａ及び第２励振電極１４ｂと、一対の引出電極を構成する第１引出電極１５ａ及び第２引出電極１５ｂと、一対の接続電極を構成する第１接続電極１６ａ及び第２接続電極１６ｂとを備えている。 The crystal vibrating element 10 is an electromechanical energy conversion element capable of converting electrical energy and mechanical energy through the piezoelectric effect. The crystal vibrating element 10 includes a flaky crystal element 11, a first excitation electrode 14a and a second excitation electrode 14b forming a pair of excitation electrodes, and a first extraction electrode forming a pair of extraction electrodes. 15a and a second extraction electrode 15b, and a first connection electrode 16a and a second connection electrode 16b forming a pair of connection electrodes.
　水晶片１１は、互いに対向する上面１１Ａ及び下面１１Ｂを有している。上面１１Ａは、ベース部材３０に対向する側とは反対側、すなわち後述する蓋部材４０の天壁部４１に対向する側に位置している。下面１１Ｂは、ベース部材３０に対向する側に位置している。上面１１Ａ及び下面１１Ｂは、水晶片１１の一対の主面に相当する。 The crystal piece 11 has an upper surface 11A and a lower surface 11B facing each other. The upper surface 11A is located on the side opposite to the side facing the base member 30, that is, on the side facing the ceiling wall portion 41 of the lid member 40, which will be described later. The lower surface 11B is located on the side facing the base member 30 . The upper surface 11A and the lower surface 11B correspond to a pair of principal surfaces of the crystal piece 11. As shown in FIG.
　水晶片１１は、例えば、ＡＴカット型の水晶結晶である。ＡＴカット型の水晶片は、Ｘ軸及びＺ’軸によって特定される面と平行な面（以下、「ＸＺ’面」とする。他の軸によって特定される面についても同様である。）が主面となり、Ｙ’軸と平行な方向が厚みとなるように形成される。一例として、上面１１Ａを平面視したときの水晶片１１の外縁は、Ｘ軸と平行な方向（以下、「Ｘ軸方向」とする。他の軸と平行な方向についても同様とする。）に延在する長辺と、Ｚ’軸方向に延在する短辺とを有している。Ｘ軸方向は「第１方向」の一例に相当し、Ｚ’軸方向は「第２方向」の一例に相当する。 The crystal piece 11 is, for example, an AT-cut crystal. The AT-cut crystal piece has a plane parallel to the plane specified by the X-axis and Z'-axis (hereinafter referred to as "XZ' plane"; the same applies to planes specified by other axes). The main surface is formed so that the direction parallel to the Y' axis becomes the thickness. As an example, when the upper surface 11A is viewed in plan, the outer edge of the crystal piece 11 is in a direction parallel to the X-axis (hereinafter referred to as “X-axis direction”; the same applies to directions parallel to other axes.). It has long sides that extend and short sides that extend in the Z′-axis direction. The X-axis direction corresponds to an example of the "first direction", and the Z'-axis direction corresponds to an example of the "second direction".
　ＡＴカット型の水晶片１１を用いた水晶振動素子１０は、広い温度範囲で高い周波数安定性を有する。ＡＴカット型の水晶振動素子１０では、厚みすべり振動モード（Ｔｈｉｃｋｎｅｓｓ　Ｓｈｅａｒ　Ｖｉｂｒａｔｉｏｎ　Ｍｏｄｅ）が主要振動として用いられる。水晶片１１のカット角度は、ＡＴカット以外の異なるカットを適用してもよい。例えばＢＴカット、ＧＴカット、ＳＣカットなどを適用してよい。 The crystal vibrating element 10 using the AT-cut crystal blank 11 has high frequency stability over a wide temperature range. In the AT-cut crystal vibrating element 10, a thickness shear vibration mode is used as a main vibration. A different cut other than the AT cut may be applied to the cut angle of the crystal piece 11 . For example, BT cut, GT cut, SC cut, etc. may be applied.
　水晶片１１の上面１１Ａを平面視したとき、水晶片１１は、電気機械エネルギー変換が行われる励振部１７と、励振部１７の外側に位置する周辺部１８とを有している。励振部１７は、矩形状の島状に設けられ、枠状の周辺部１８に囲まれている。励振部１７は上面１７Ａ及び下面１７Ｂを有し、周辺部１８は上面１８Ａ及び下面１８Ｂを有している。上面１７Ａ，１８Ａは水晶片１１の上面１１Ａの一部であり、下面１７Ｂ，１８Ｂは水晶片１１の下面１１Ｂの一部である。 When the upper surface 11A of the crystal piece 11 is viewed in plan, the crystal piece 11 has an excitation portion 17 where electromechanical energy conversion is performed, and a peripheral portion 18 positioned outside the excitation portion 17. The excitation unit 17 is provided in a rectangular island shape and surrounded by a frame-shaped peripheral portion 18 . The excitation section 17 has an upper surface 17A and a lower surface 17B, and the peripheral section 18 has an upper surface 18A and a lower surface 18B. The upper surfaces 17A and 18A are part of the upper surface 11A of the crystal piece 11, and the lower surfaces 17B and 18B are parts of the lower surface 11B of the crystal piece 11. FIG.
　水晶片１１は、励振部１７の厚みが周辺部１８の厚みよりも大きい、いわゆるメサ型構造である。励振部１７においてメサ型構造を有する水晶片１１によれば、水晶振動素子１０の振動漏れが抑制できる。また、外部応力による周波数変動が抑制できる。水晶片１１は両面メサ型構造であり、上面１１Ａ及び下面１１Ｂの両側において、励振部１７が周辺部１８から突出している。励振部１７と周辺部１８との間の境界領域は、厚みが連続的に変化するテーパ形状を成している。言い換えると、励振部１７及び周辺部１８のそれぞれの上面１７Ａ，１８Ａ同士を繋ぐ面、及び下面１７Ｂ，１８Ｂ同士を繋ぐ面は、傾きが一様な傾斜面である。 The crystal piece 11 has a so-called mesa structure in which the excitation portion 17 is thicker than the peripheral portion 18 . According to the crystal piece 11 having the mesa structure in the excitation portion 17, vibration leakage of the crystal vibrating element 10 can be suppressed. Also, frequency fluctuation due to external stress can be suppressed. The crystal piece 11 has a double-sided mesa structure, and excitation portions 17 protrude from a peripheral portion 18 on both sides of the upper surface 11A and the lower surface 11B. A boundary region between the excitation portion 17 and the peripheral portion 18 has a tapered shape in which the thickness continuously changes. In other words, the surfaces connecting the upper surfaces 17A and 18A and the surfaces connecting the lower surfaces 17B and 18B of the excitation portion 17 and the peripheral portion 18 are uniformly inclined surfaces.
　なお、励振部１７及び周辺部１８の構造は上記に限定されるものではない。例えば、励振部１７及び周辺部１８は、それぞれ、水晶片１１のＺ’軸方向に沿った全幅に亘って帯状に形成されてもよい。また、励振部１７と周辺部１８との間の境界領域は、厚みの変化が不連続な階段形状を成してもよい。当該境界領域は、厚みの変化量が連続的に変化するコンベックス構造、又は厚みの変化量が不連続に変化するベベル構造であってもよい。また、水晶片１１は、励振部１７の厚みが周辺部１８の厚みよりも小さい、いわゆる逆メサ型構造であってもよい。水晶片１１は、励振部１７の厚みと周辺部１８の厚みとが略等しい平板状であってもよい。 The structures of the excitation section 17 and the peripheral section 18 are not limited to the above. For example, the excitation portion 17 and the peripheral portion 18 may each be formed in a strip shape over the entire width of the crystal piece 11 along the Z′-axis direction. Also, the boundary region between the excitation portion 17 and the peripheral portion 18 may have a stepped shape in which the change in thickness is discontinuous. The boundary region may have a convex structure in which the amount of change in thickness changes continuously, or a bevel structure in which the amount of change in thickness changes discontinuously. Further, the crystal blank 11 may have a so-called inverted mesa structure in which the thickness of the excitation portion 17 is smaller than the thickness of the peripheral portion 18 . The crystal piece 11 may have a flat plate shape in which the thickness of the excitation portion 17 and the thickness of the peripheral portion 18 are substantially equal.
　第１励振電極１４ａ及び第２励振電極１４ｂは、励振部１７の中央部に設けられている。第１励振電極１４ａは、励振部１７の上面１７Ａに設けられ、第２励振電極１４ｂは、励振部１７の下面１７Ｂに設けられている。第１励振電極１４ａと第２励振電極１４ｂとは、励振部１７を挟んで互いに対向し、励振部１７に対して電圧を印加可能に構成されている。 The first excitation electrode 14 a and the second excitation electrode 14 b are provided in the central portion of the excitation section 17 . The first excitation electrode 14 a is provided on the upper surface 17 A of the excitation section 17 , and the second excitation electrode 14 b is provided on the lower surface 17 B of the excitation section 17 . The first excitation electrode 14 a and the second excitation electrode 14 b face each other with the excitation section 17 interposed therebetween, and are configured to be able to apply a voltage to the excitation section 17 .
　第１引出電極１５ａ及び第２引出電極１５ｂは、励振部１７から周辺部１８に亘って設けられている。第１引出電極１５ａは、励振部１７の上面１７Ａにおいて第１励振電極１４ａに接続され、周辺部１８において第１接続電極１６ａに接続されている。第２引出電極１５ｂは、励振部１７の下面１７Ｂにおいて第２励振電極１４ｂに接続され、周辺部１８において第２接続電極１６ｂに接続されている。 The first extraction electrode 15 a and the second extraction electrode 15 b are provided from the excitation section 17 to the peripheral section 18 . The first extraction electrode 15 a is connected to the first excitation electrode 14 a on the upper surface 17 A of the excitation section 17 and connected to the first connection electrode 16 a on the peripheral section 18 . The second extraction electrode 15b is connected to the second excitation electrode 14b on the lower surface 17B of the excitation section 17 and to the second connection electrode 16b on the peripheral section 18 .
　第１接続電極１６ａ及び第２接続電極１６ｂは、周辺部１８の下面１８Ｂに設けられている。第１接続電極１６ａ及び第２接続電極１６ｂは、水晶片１１の上面１１Ａを平面視したとき、Ｘ軸方向の端部（水晶片１１の短辺）側に配置されている。言い換えると、第１接続電極１６ａ及び第２接続電極１６ｂは、周辺部１８のうち、第１励振電極１４ａ及び第２励振電極１４ｂに対してＸ軸方向の負方向（矢印の向きとは反対方向）側に位置する領域に設けられている。また、第１接続電極１６ａ及び第２接続電極１６ｂはＺ’軸方向に並んでおり、第２接続電極１６ｂは第１接続電極１６ａよりもＺ’軸方向の負方向側に位置している。第１接続電極１６ａは、第１引出電極１５ａを介して第１励振電極１４ａに電気的に接続されている。第２接続電極１６ｂは、第２引出電極１５ｂを介して第２励振電極１４ｂに電気的に接続されている。 The first connection electrode 16a and the second connection electrode 16b are provided on the lower surface 18B of the peripheral portion 18. The first connection electrode 16a and the second connection electrode 16b are arranged on the end (the short side of the crystal piece 11) in the X-axis direction when the upper surface 11A of the crystal piece 11 is viewed from above. In other words, the first connection electrode 16a and the second connection electrode 16b are arranged in the negative direction of the X-axis (the direction opposite to the direction of the arrow) with respect to the first excitation electrode 14a and the second excitation electrode 14b in the peripheral portion 18. ) is provided in the region located on the side. The first connection electrode 16a and the second connection electrode 16b are arranged in the Z'-axis direction, and the second connection electrode 16b is located on the negative side of the Z'-axis direction with respect to the first connection electrode 16a. The first connection electrode 16a is electrically connected to the first excitation electrode 14a through the first extraction electrode 15a. The second connection electrode 16b is electrically connected to the second excitation electrode 14b via the second extraction electrode 15b.
　一対の励振電極１４ａ，１４ｂと一対の接続電極１６ａ，１６ｂとの間の水晶片１１の領域には、水晶片１１を貫通する貫通孔２０が形成されている。貫通孔２０は、周辺部１８のうち、第１励振電極１４ａと第１接続電極１６ａとの間の領域から、第２励振電極１４ｂと第２接続電極１６ｂとの間の領域に亘ってＺ’軸方向に延在している。上面１１Ａを平面視したとき、貫通孔２０の形状は、例えば、Ｚ’軸方向を長手方向とする長方形状である。 A through-hole 20 passing through the crystal piece 11 is formed in a region of the crystal piece 11 between the pair of excitation electrodes 14a and 14b and the pair of connection electrodes 16a and 16b. The through hole 20 extends from the region between the first excitation electrode 14a and the first connection electrode 16a in the peripheral portion 18 to the region between the second excitation electrode 14b and the second connection electrode 16b. It extends axially. When the upper surface 11A is viewed in plan, the shape of the through hole 20 is, for example, a rectangular shape whose longitudinal direction is the Z'-axis direction.
　第１励振電極１４ａ、第１引出電極１５ａ及び第１接続電極１６ａは、連続しており一体的に形成されている。第２励振電極１４ｂ、第２引出電極１５ｂ及び第２接続電極１６ｂも同様である。これら水晶振動素子１０の電極は、例えば、水晶片１１との密着性が良好な材料で設けられた下地層と、化学的安定性が良好な材料で設けられた表面層とを含む導電性の多層膜である。下地層は例えばクロム（Ｃｒ）層であり、最表層は例えば金（Ａｕ）層である。 The first excitation electrode 14a, the first extraction electrode 15a and the first connection electrode 16a are continuous and integrally formed. The same applies to the second excitation electrode 14b, the second extraction electrode 15b, and the second connection electrode 16b. The electrodes of these crystal vibrating elements 10 are conductive electrodes including, for example, a base layer made of a material with good adhesion to the crystal piece 11 and a surface layer made of a material with good chemical stability. It is a multilayer film. The underlying layer is, for example, a chromium (Cr) layer, and the outermost layer is, for example, a gold (Au) layer.
　ベース部材３０は、基体３１と、一対の電極パッドを構成する第１電極パッド３３ａ及び第２電極パッド３３ｂと、一対の貫通電極を構成する第１貫通電極３４ａ及び第２貫通電極３４ｂと、第１外部電極３５ａ～第４外部電極３５ｄとを備えている。 The base member 30 includes a substrate 31, a first electrode pad 33a and a second electrode pad 33b forming a pair of electrode pads, a first through electrode 34a and a second through electrode 34b forming a pair of through electrodes, and a 1 external electrode 35a to fourth external electrode 35d.
　基体３１は、上面３１Ａ及び下面３１Ｂを有する板状の絶縁体である、基体３１は、例えば絶縁性セラミック（アルミナなど）の焼結材である。熱応力の発生を抑制する観点から、基体３１は耐熱性材料によって構成されることが好ましい。リフロー等の熱履歴によってベース部材３０が水晶振動素子１０にかける応力を抑制する観点から、基体３１は、水晶片１１に近い熱膨張率を有する材料によって設けられてもよく、例えば水晶によって設けられてもよい。 The base 31 is a plate-like insulator having an upper surface 31A and a lower surface 31B. The base 31 is, for example, a sintered material of insulating ceramic (alumina, etc.). From the viewpoint of suppressing the generation of thermal stress, the substrate 31 is preferably made of a heat-resistant material. From the viewpoint of suppressing the stress that the base member 30 applies to the crystal vibrating element 10 due to thermal history such as reflow, the substrate 31 may be made of a material having a coefficient of thermal expansion close to that of the crystal piece 11. For example, it may be made of crystal. may
　第１電極パッド３３ａ及び第２電極パッド３３ｂは、基体３１の上面３１Ａに設けられている。第１電極パッド３３ａ及び第２電極パッド３３ｂは、ベース部材３０に水晶振動素子１０を電気的に接続するための端子である。第１電極パッド３３ａ及び第２電極パッド３３ｂは、例えば、表面にＡｕ層を含む導電性の多層膜である。 The first electrode pad 33 a and the second electrode pad 33 b are provided on the upper surface 31 A of the base 31 . The first electrode pad 33 a and the second electrode pad 33 b are terminals for electrically connecting the crystal vibrating element 10 to the base member 30 . The first electrode pad 33a and the second electrode pad 33b are, for example, a conductive multilayer film including an Au layer on its surface.
　第１貫通電極３４ａ及び第２貫通電極３４ｂは、基体３１をＺ’軸方向に貫通している。第１貫通電極３４ａは、第１電極パッド３３ａと第１外部電極３５ａとを電気的に接続している。第２貫通電極３４ｂは、第２電極パッド３３ｂと第２外部電極３５ｂとを電気的に接続している。 The first through electrode 34a and the second through electrode 34b penetrate the base 31 in the Z'-axis direction. The first through electrode 34a electrically connects the first electrode pad 33a and the first external electrode 35a. The second through electrode 34b electrically connects the second electrode pad 33b and the second external electrode 35b.
　第１外部電極３５ａ～第４外部電極３５ｄは、基体３１の下面３１Ｂに設けられている。第１外部電極３５ａ及び第２外部電極３５ｂは、水晶振動子１を外部基板に電気的に接続するための端子である。第３外部電極３５ｃ及び第４外部電極３５ｄは、例えば電気信号等が入出力されないダミー電極であるが、蓋部材４０を接地させて蓋部材４０の電磁シールド機能を向上させる接地電極であってもよい。 The first to fourth external electrodes 35a to 35d are provided on the lower surface 31B of the substrate 31. The first external electrode 35a and the second external electrode 35b are terminals for electrically connecting the crystal resonator 1 to an external substrate. The third external electrode 35c and the fourth external electrode 35d are dummy electrodes to which, for example, electrical signals are not input/output. good.
　第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂは、水晶振動素子１０を励振可能に保持している。言い換えると、第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂは、励振部１７がベース部材３０及び蓋部材４０に接触しないように、水晶振動素子１０を保持している。また、第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂは、水晶振動素子１０とベース部材３０とを電気的に接続している。具体的には、第１導電性保持部材３６ａが第１電極パッド３３ａと第１接続電極１６ａとを電気的に接続し、第２導電性保持部材３６ｂが第２電極パッド３３ｂと第２接続電極１６ｂとを電気的に接続している。 The first conductive holding member 36a and the second conductive holding member 36b hold the crystal vibrating element 10 so that it can be excited. In other words, the first conductive holding member 36 a and the second conductive holding member 36 b hold the crystal vibrating element 10 so that the excitation section 17 does not contact the base member 30 and the lid member 40 . Also, the first conductive holding member 36 a and the second conductive holding member 36 b electrically connect the crystal vibrating element 10 and the base member 30 . Specifically, the first conductive holding member 36a electrically connects the first electrode pad 33a and the first connection electrode 16a, and the second conductive holding member 36b connects the second electrode pad 33b and the second connection electrode. 16b are electrically connected.
　第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂは、熱硬化性樹脂や光硬化性樹脂等を含む導電性接着剤の硬化物である。第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂの主成分は、例えばシリコーン樹脂である。第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂは導電性粒子を含んでおり、当該導電性粒子としては例えば銀（Ａｇ）を含む金属粒子が用いられる。 The first conductive holding member 36a and the second conductive holding member 36b are cured conductive adhesives containing thermosetting resin, photo-setting resin, or the like. A main component of the first conductive holding member 36a and the second conductive holding member 36b is, for example, silicone resin. The first conductive holding member 36a and the second conductive holding member 36b contain conductive particles, and metal particles containing silver (Ag), for example, are used as the conductive particles.
　第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂの主成分は、硬化性樹脂であればシリコーン樹脂に限定されるものではなく、例えばエポキシ樹脂やアクリル樹脂などであってもよい。また、第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂの導電性は、銀粒子による付与に限定されるものではなく、その他の金属、導電性セラミック、導電性有機材料などによって付与されてもよい。第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂの主成分が導電性高分子であってもよい。 The main component of the first conductive holding member 36a and the second conductive holding member 36b is not limited to silicone resin as long as it is a curable resin, and may be, for example, epoxy resin or acrylic resin. Further, the conductivity of the first conductive holding member 36a and the second conductive holding member 36b is not limited to being imparted by silver particles, and may be imparted by other metals, conductive ceramics, conductive organic materials, and the like. may The main component of the first conductive holding member 36a and the second conductive holding member 36b may be a conductive polymer.
　蓋部材４０は、ベース部材３０との間に水晶振動素子１０を収容する内部空間を形成する。蓋部材４０はベース部材３０の側に開口する凹部４９を有しており、本実施形態における内部空間は、凹部４９の内側の空間に相当する。蓋部材４０は、平板状の天壁部４１と、天壁部４１の外縁からベース部材３０に向かって延在する側壁部４２とを有している。蓋部材４０の凹部４９は、天壁部４１と側壁部４２とによって形成されている。蓋部材４０はさらに、側壁部４２のベース部材３０側の先端部に接続されており且つ基体３１の上面３１Ａに沿って外側に延在するフランジ部４３を有している。基体３１の上面３１Ａを平面視したとき、フランジ部４３は、水晶振動素子１０を囲むように枠状に延在している。 The lid member 40 and the base member 30 form an internal space that accommodates the crystal vibrating element 10 . The lid member 40 has a recess 49 that opens toward the base member 30 , and the internal space in this embodiment corresponds to the space inside the recess 49 . The lid member 40 has a flat top wall portion 41 and side wall portions 42 extending from the outer edge of the top wall portion 41 toward the base member 30 . The recessed portion 49 of the lid member 40 is formed by the ceiling wall portion 41 and the side wall portion 42 . The lid member 40 further has a flange portion 43 connected to the tip of the side wall portion 42 on the base member 30 side and extending outward along the upper surface 31A of the base 31 . When the upper surface 31</b>A of the base 31 is viewed from above, the flange portion 43 extends like a frame so as to surround the crystal vibrating element 10 .
　蓋部材４０の材質は、望ましくは導電材料であり、さらに望ましくは気密性の高い金属材料である。蓋部材４０が導電材料で構成されることによって、内部空間への電磁波の出入りを低減する電磁シールド機能が蓋部材４０に付与される。熱応力の発生を抑制する観点から、蓋部材４０の材質は、基体３１に近い熱膨張率を有する材料であることが望ましく、例えば常温付近での熱膨張率がガラスやセラミックと広い温度範囲で一致するＦｅ－Ｎｉ－Ｃｏ系合金である。 The material of the lid member 40 is desirably a conductive material, more desirably a highly airtight metal material. Since the cover member 40 is made of a conductive material, the cover member 40 is provided with an electromagnetic shielding function that reduces the entry and exit of electromagnetic waves into the internal space. From the viewpoint of suppressing the generation of thermal stress, the material of the lid member 40 is desirably a material having a coefficient of thermal expansion close to that of the base 31. For example, the coefficient of thermal expansion near room temperature is glass or ceramic, which can be used over a wide temperature range. It is a matching Fe--Ni--Co based alloy.
　接合部材５０は、ベース部材３０及び蓋部材４０の各全周に亘って設けられ、矩形の枠状をなしている。ベース部材３０の上面３１Ａを平面視したとき、第１電極パッド３３ａ及び第２電極パッド３３ｂは、接合部材５０の内側に配置されており、接合部材５０は水晶振動素子１０を囲むように設けられている。接合部材５０は、ベース部材３０と蓋部材４０とを接合し、内部空間に相当する凹部４９を封止している。具体的には、接合部材５０は、基体３１とフランジ部４３とを接合している。 The joint member 50 is provided over the entire perimeter of the base member 30 and the lid member 40 and has a rectangular frame shape. When the upper surface 31A of the base member 30 is viewed in plan, the first electrode pads 33a and the second electrode pads 33b are arranged inside the bonding member 50, and the bonding member 50 is provided so as to surround the crystal vibrating element 10. ing. The joining member 50 joins the base member 30 and the lid member 40 and seals the recess 49 corresponding to the internal space. Specifically, the joining member 50 joins the base 31 and the flange portion 43 .
　接合部材５０は、例えば、基体３１の上面３１Ａに設けられたモリブデン（Ｍｏ）からなるメタライズ層と、メタライズ層とフランジ部４３との間に設けられた金錫（Ａｕ－Ｓｎ）系の共晶合金からなる金属半田層とによって設けられている。接合部材５０の材質は上記に限定されるものではないが、水晶振動素子１０の周波数特性の変動を抑制する観点から透湿性が低いことが望ましく、ガス透過性が低いことがさらに望ましい。また、接合部材５０を介して蓋部材４０を接地電位に電気的に接続するためには、接合部材５０が導電性を有することが望ましい。ベース部材３０と蓋部材４０とは、シーム溶接によって接合されてもよい。 The joining member 50 includes, for example, a metallized layer made of molybdenum (Mo) provided on the upper surface 31A of the base 31, and a gold-tin (Au—Sn)-based eutectic layer provided between the metallized layer and the flange portion 43. It is provided by a metal solder layer made of an alloy. Although the material of the bonding member 50 is not limited to the above, it preferably has low moisture permeability from the viewpoint of suppressing fluctuations in the frequency characteristics of the crystal oscillator 10, and more preferably has low gas permeability. Moreover, in order to electrically connect the lid member 40 to the ground potential via the joint member 50, it is desirable that the joint member 50 has conductivity. The base member 30 and the lid member 40 may be joined by seam welding.
　次に、図３～図７を参照しつつ、導電性保持部材、水晶片及び貫通孔の位置関係等について説明する。図３は、第１実施形態に係る水晶振動素子の構成を概略的に示す平面図である。図４は、応力変化率を示すグラフである。また、図５から図７はそれぞれ応力分布を示す図である。 Next, with reference to FIGS. 3 to 7, the positional relationship among the conductive holding member, the crystal piece, and the through-hole will be described. FIG. 3 is a plan view schematically showing the configuration of the crystal oscillator according to the first embodiment. FIG. 4 is a graph showing the stress change rate. Moreover, FIGS. 5-7 is a figure which shows stress distribution, respectively.
　図３を参照しつつ、水晶振動素子１０を平面視したときの各部の寸法（間隔Ｓ１、長さＬ１、幅Ｗ１，Ｗ２、径Ｒ１）について説明する。間隔Ｓ１は、第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂのそれぞれの縁部のうち、Ｚ’方向における互いに最も離間する部分同士の間の間隔である。より詳細には、第１導電性保持部材３６ａの最もＺ’軸方向正方向側に位置する縁部と、第２導電性保持部材３６ｂの最もＺ’軸方向負方向側に位置する縁部との間のＺ軸方向における距離である。長さＬ１は、貫通孔２０のＺ’方向における長さである。より詳細には、貫通孔２０の最もＺ’軸方向正方向側に位置する内側面と、貫通孔２０の最もＺ’軸方向負方向側に位置する内側面との間のＺ軸方向における距離である。幅Ｗ１は、水晶片１１のＺ’方向における幅である。より詳細には、励振部１７のＺ’軸方向正方向側に位置する水晶片１１の縁部と、励振部１７のＺ’軸方向負方向側に位置する水晶片１１の縁部との間のＺ軸方向における距離である。幅Ｗ２は、励振部１７のＺ’方向における幅である。より詳細には、励振部１７とＺ’軸方向正方向側の周辺部１８との間の境界領域における外側の縁部と、周辺部１８とＺ’軸方向正方向側の周辺部１８との間の境界領域における外側の縁部との間の距離である。径Ｒ１は、第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂの直径である。但し、第１導電性保持部材３６ａの直径は、第２導電性保持部材３６ｂの直径と異なっていてもよい。 The dimensions (spacing S1, length L1, widths W1 and W2, diameter R1) of each part when the crystal resonator element 10 is viewed in plan will be described with reference to FIG. The space S1 is the space between the edges of the first conductive holding member 36a and the second conductive holding member 36b, which are the farthest from each other in the Z' direction. More specifically, the edge portion of the first conductive holding member 36a located on the most positive side in the Z′-axis direction and the edge portion of the second conductive holding member 36b located on the most negative side in the Z′-axis direction. is the distance in the Z-axis direction between The length L1 is the length of the through-hole 20 in the Z' direction. More specifically, the distance in the Z-axis direction between the inner surface of the through-hole 20 located on the most positive Z'-axis direction side and the inner surface of the through-hole 20 located on the most negative Z'-axis direction side. is. Width W1 is the width of crystal blank 11 in the Z′ direction. More specifically, between the edge portion of the crystal piece 11 located on the positive side of the excitation portion 17 in the Z′-axis direction and the edge portion of the crystal piece 11 located on the side of the excitation portion 17 in the negative Z′-axis direction. is the distance in the Z-axis direction. Width W2 is the width of excitation section 17 in the Z′ direction. More specifically, the outer edge of the boundary region between the excitation portion 17 and the peripheral portion 18 on the positive Z′-axis direction side, and the boundary between the peripheral portion 18 and the peripheral portion 18 on the positive Z′-axis direction side. is the distance between the outer edges in the boundary area between The diameter R1 is the diameter of the first conductive retaining member 36a and the second conductive retaining member 36b. However, the diameter of the first conductive holding member 36a may be different from the diameter of the second conductive holding member 36b.
　図４に示すグラフの横軸は、長さＬ１に対する間隔Ｓ１の割合を示し、縦軸は、Ｓ１／Ｌ１が最も小さいときの応力を基準した応力変化率を示している。本グラフにおける応力は、水晶振動子１を外部基板にリフロー半田付けしたとき、ベース部材３０から第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂを介して水晶振動素子１０に伝搬する熱応力のシミュレーションを基に算出している。実線及び破線は、ともに、水晶片１１のＸ軸方向の長さを０．７６ｍｍ、幅Ｗ１を０．６８ｍｍ、幅Ｗ２を０．５６ｍｍとする水晶振動素子１０における励振部１７にかかる応力の積分値の変化を示している。実線は、間隔Ｓ１を０．３７ｍｍとした場合に、長さＬ１を変化させたときの各々のＳ１／Ｌ１における励振部１７の最大応力が、長さＬ１が０．６のときの励振部１７の最大応力に比べてどれだけ増加したかを示している。破線は、間隔Ｓ１を０．６１ｍｍとした場合に、長さＬ１を変化させたときの各々のＳ１／Ｌ１における励振部１７の最大応力が、長さＬ１が０．６のときの励振部１７の最大応力に比べてどれだけ増加したかを示している。 The horizontal axis of the graph shown in FIG. 4 indicates the ratio of the interval S1 to the length L1, and the vertical axis indicates the stress change rate based on the stress when S1/L1 is the smallest. The stress in this graph is the heat that propagates from the base member 30 to the crystal vibrating element 10 via the first conductive holding member 36a and the second conductive holding member 36b when the crystal oscillator 1 is reflow soldered to an external substrate. Calculated based on stress simulations. Both the solid line and the broken line are integrals of the stress applied to the excitation part 17 in the crystal element 10 where the length in the X-axis direction of the crystal blank 11 is 0.76 mm, the width W1 is 0.68 mm, and the width W2 is 0.56 mm. It shows a change in value. The solid line indicates the maximum stress of the excitation portion 17 at each S1/L1 when the length L1 is changed when the interval S1 is 0.37 mm. It shows how much it increased compared to the maximum stress of The dashed line indicates the maximum stress of the excitation portion 17 at each S1/L1 when the length L1 is changed when the interval S1 is 0.61 mm. It shows how much it increased compared to the maximum stress of
　図５は、図４に示す実線の条件であって、Ｌ１＝０．４７５ｍｍとしたとき、すなわちＳ１／Ｌ１＝０．８のときの応力分布のシミュレーション結果を示している。図６は、図４に示す実線の条件であって、Ｌ１＝０．４３５ｍｍとしたとき、すなわちＳ１／Ｌ１＝０．８５のときの応力分布のシミュレーション結果を示している。図７は、図４に示す破線の条件であって、Ｌ１＝０．４０７ｍｍとしたとき、すなわちＳ１／Ｌ１＝１．５のときの応力分布のシミュレーション結果を示している。 FIG. 5 shows simulation results of stress distribution under the solid line condition shown in FIG. 4 and when L1=0.475 mm, that is, when S1/L1=0.8. FIG. 6 shows simulation results of the stress distribution under the solid line condition shown in FIG. 4 and when L1=0.435 mm, that is, when S1/L1=0.85. FIG. 7 shows simulation results of stress distribution when L1=0.407 mm, that is, when S1/L1=1.5 under the broken line condition shown in FIG.
　図４に示すように、間隔Ｓ１と長さＬ１とがＳ１／Ｌ１≦１．５の関係を有するとき、Ｓ１／Ｌ１と応力変化率は線形的な比例関係に漸近し、Ｓ１／Ｌ１が小さいほど励振部１７にかかる応力が小さくなる。また、上記範囲においては、図５～図７に示すように、Ｓ１／Ｌ１が小さいほど、励振部１７における熱応力の影響を抑制できる。特に、Ｓ１／Ｌ１が小さいほど、励振部１７の中央部における応力変化が抑制できる。したがって、Ｓ１／Ｌ１≦１．５であれば、リフローの熱応力などの外部応力がベース部材３０から水晶振動素子１０に伝搬したとしても、励振部１７にかかる応力が緩和できるため、周波数の変動が抑制できる。 As shown in FIG. 4, when the interval S1 and the length L1 have a relationship of S1/L1 ≤ 1.5, S1/L1 and the stress change rate approach a linear proportional relationship, and S1/L1 is small. The stress applied to the excitation unit 17 decreases as the value increases. In the above range, as shown in FIGS. 5 to 7, the smaller S1/L1 is, the more the effect of thermal stress in the excitation section 17 can be suppressed. In particular, the smaller S1/L1 is, the more the stress change in the central portion of the excitation section 17 can be suppressed. Therefore, if S1/L1≤1.5, even if external stress such as reflow thermal stress is propagated from the base member 30 to the crystal oscillator 10, the stress applied to the excitation unit 17 can be alleviated. can be suppressed.
　また、間隔Ｓ１と長さＬ１とは、望ましくは０．６≦Ｓ１／Ｌ１の関係を有している。これによれば、第１導電性保持部材３６ａと第２導電性保持部材３６ｂとが充分離間するため、製造誤差によって第１導電性保持部材３６ａと第２導電性保持部材３６ｂとの位置や大きさが変動したとしても、第１導電性保持部材３６ａと第２導電性保持部材３６ｂとの短絡による不具合の発生が抑制できる。間隔Ｓ１と長さＬ１とは、さらに望ましくは０．８≦Ｓ１／Ｌ１の関係を有している。これによれば、第１導電性保持部材３６ａと第２導電性保持部材３６ｂとの短絡による不具合の発生がさらに抑制できる。また、水晶振動素子１０の保持位置が離れていることにより、水晶振動素子１０の保持強度の低下が抑制でき、水晶振動素子１０の脱落等の損傷による不具合の発生が抑制できる。 Also, the interval S1 and the length L1 desirably have a relationship of 0.6≦S1/L1. According to this, since the first conductive holding member 36a and the second conductive holding member 36b are separated sufficiently, the positions and sizes of the first conductive holding member 36a and the second conductive holding member 36b may vary due to manufacturing errors. Even if the voltage fluctuates, it is possible to suppress the occurrence of problems due to short-circuiting between the first conductive holding member 36a and the second conductive holding member 36b. The interval S1 and the length L1 more preferably have a relationship of 0.8≦S1/L1. According to this, it is possible to further suppress the occurrence of problems due to short-circuiting between the first conductive holding member 36a and the second conductive holding member 36b. In addition, since the holding position of the crystal oscillator 10 is separated, the holding strength of the crystal oscillator 10 can be suppressed from being lowered, and the occurrence of problems due to damage such as dropout of the crystal oscillator 10 can be suppressed.
　長さＬ１と幅Ｗ１とは、望ましくは０．５５≦Ｌ１／Ｗ１の関係を有している。これによれば、間隔Ｓ１と長さＬ１とがＳ１／Ｌ１≦１．５の関係を有している場合に、長さＬ１が充分に大きいため間隔Ｓ１も充分に大きくできる。したがって、第１導電性保持部材３６ａと第２導電性保持部材３６ｂとが充分に離間し、導電性保持部材同士の短絡や水晶振動子の損傷などの不具合の発生が抑制できる。また、長さＬ１と幅Ｗ１とは、望ましくはＬ１／Ｗ１≦０．７５の関係を有している。これによれば、貫通孔２０が存在することによる水晶片１１の機械的強度の低下を抑制し、水晶振動素子１０の損傷による不具合の発生が抑制できる。また、貫通孔２０からＺ’軸方向の正方向側及び負方向側に、充分な面積の上面１１Ａ及び下面１１Ｂが確保できるため、第１引出電極１５ａ及び第２引出電極１５ｂの狭小化による断線等の不具合の発生が抑制できる。 The length L1 and width W1 desirably have a relationship of 0.55≦L1/W1. According to this, when the interval S1 and the length L1 have a relationship of S1/L1≦1.5, the interval S1 can be made sufficiently large because the length L1 is sufficiently large. Therefore, the first conductive holding member 36a and the second conductive holding member 36b are sufficiently spaced apart, and problems such as short-circuiting between the conductive holding members and damage to the crystal oscillator can be suppressed. Moreover, the length L1 and the width W1 desirably have a relationship of L1/W1≦0.75. According to this, it is possible to suppress the deterioration of the mechanical strength of the crystal piece 11 due to the presence of the through holes 20, and to suppress the occurrence of defects due to the damage of the crystal vibrating element 10. FIG. In addition, since the upper surface 11A and the lower surface 11B having sufficient areas can be secured on the positive and negative Z′-axis direction sides from the through hole 20, disconnection due to narrowing of the first lead-out electrode 15a and the second lead-out electrode 15b can be avoided. It is possible to suppress the occurrence of defects such as
　間隔Ｓ１及び径Ｒ１は、望ましくは０．２≦Ｓ１／Ｒ１の関係を有している。これによれば、第１導電性保持部材３６ａと第２導電性保持部材３６ｂとが充分に離間し、導電性保持部材同士の短絡や水晶振動子の損傷などの不具合の発生が抑制できる。間隔Ｓ１及び径Ｒ１は、望ましくはＳ１／Ｒ１≦０．３５の関係を有している。これによれば、第１導電性保持部材３６ａ及び第２導電性保持部材３６ｂの小型化に起因した不具合、例えば、水晶振動素子１０の保持強度の低下や、水晶振動素子１０のベース部材３０との接触などが抑制できる。 The distance S1 and the radius R1 desirably have a relationship of 0.2≦S1/R1. According to this, the first conductive holding member 36a and the second conductive holding member 36b are sufficiently spaced apart, and it is possible to suppress the occurrence of problems such as short-circuiting between the conductive holding members and damage to the crystal oscillator. The distance S1 and the radius R1 desirably have a relationship of S1/R1≦0.35. According to this, problems caused by the miniaturization of the first conductive holding member 36a and the second conductive holding member 36b, such as a decrease in the holding strength of the crystal vibration element 10 and the base member 30 of the crystal vibration element 10 contact can be suppressed.
　図３に示す構成は上記の位置関係等を満たす一例であり、図３における各部の寸法は、２×Ｒ１＜Ｓ１＜Ｌ１＜Ｗ１＜Ｗ２の関係を有しているが、これに限定されるものではない。例えば、間隔Ｓ１と長さＬ１とは、０．８≦Ｓ１／Ｌ１≦１．５の関係を有していれば、Ｌ１≦Ｓ１の関係を有してもよい。また、幅Ｗ２と長さＬ１と間隔Ｓ１とは、Ｗ２≦Ｌ１の関係を有してもよく、Ｗ２≦Ｓ１の関係を有してもよい。なお、幅Ｗ１，Ｗ２はＷ１＝Ｗ２の関係を有してもよい。 The configuration shown in FIG. 3 is an example that satisfies the above positional relationship and the like, and the dimensions of each part in FIG. not a thing For example, the interval S1 and the length L1 may have a relationship of L1≦S1 as long as they have a relationship of 0.8≦S1/L1≦1.5. Further, the width W2, the length L1, and the interval S1 may have a relationship of W2≦L1, or may have a relationship of W2≦S1. Note that the widths W1 and W2 may have a relationship of W1=W2.
　以下に、本発明の実施形態の一部又は全部を付記し、その効果について説明する。なお、本発明は以下の付記に限定されるものではない。 Some or all of the embodiments of the present invention will be added below, and their effects will be described. In addition, the present invention is not limited to the following additional remarks.
　本発明の一態様によれば、水晶片と、水晶片に設けられ互いに対向する一対の励振電極と、水晶片に設けられ一対の励振電極に電気的に接続された一対の接続電極とを有し、一対の接続電極は、水晶片の平面視における第１方向及び第１方向に交差する第２方向のうち第１方向の端部側に配置された、水晶振動素子と、一対の電極パッドを有するベース部材と、水晶振動素子の一対の接続電極とベース部材の一対の電極パッドとを電気的に接続し、ベース部材の上方に水晶振動素子を保持する、一対の導電性保持部材とを備え、第１方向における一対の励振電極と一対の接続電極との間の水晶片の領域には、水晶片を貫通する貫通孔が設けられ、一対の導電性保持部材のそれぞれの縁部のうち第２方向における互いに最も離間する部分同士の間の間隔Ｓ１と、貫通孔の第２方向における長さＬ１とは、Ｓ１／Ｌ１≦１．５の関係を有する。
　これによれば、励振部１７における熱応力の影響を抑制できる。特に、Ｓ１／Ｌ１が小さいほど、励振部１７の中央部における応力変化が抑制できる。したがって、リフローの熱応力などの外部応力がベース部材から水晶振動素子に伝搬したとしても、励振部にかかる応力が緩和できるため、周波数の変動が抑制できる。 According to one aspect of the present invention, the crystal blank includes a pair of excitation electrodes provided on the crystal blank and facing each other, and a pair of connection electrodes provided on the crystal blank and electrically connected to the pair of excitation electrodes. The pair of connection electrodes includes a crystal vibrating element and a pair of electrode pads, which are arranged on the end side of the first direction in the first direction and the second direction intersecting the first direction in plan view of the crystal piece. and a pair of conductive holding members that electrically connect the pair of connection electrodes of the crystal oscillator and the pair of electrode pads of the base member and hold the crystal oscillator above the base member a through hole penetrating through the crystal piece is provided in a region of the crystal piece between the pair of excitation electrodes and the pair of connection electrodes in the first direction; The distance S1 between the portions that are most distant from each other in the second direction and the length L1 of the through hole in the second direction have a relationship of S1/L1≦1.5.
According to this, the influence of the thermal stress in the excitation part 17 can be suppressed. In particular, the smaller S1/L1 is, the more the stress change in the central portion of the excitation section 17 can be suppressed. Therefore, even if external stress such as reflow thermal stress propagates from the base member to the crystal vibrating element, the stress applied to the excitation section can be alleviated, so that frequency fluctuation can be suppressed.
　一態様として、間隔Ｓ１と長さＬ１とは、０．８≦Ｓ１／Ｌ１の関係を有する。
　これによれば、一対の導電性保持部材が互いに充分離間するため、製造誤差によって一対の導電性保持部材の位置や大きさが変動したとしても、一対の導電性保持部材の短絡による不具合の発生が抑制できる。また、水晶振動素子の保持位置が離れていることにより、水晶振動素子の保持強度の低下が抑制でき、水晶振動素子の脱落等の損傷による不具合の発生が抑制できる。 As one aspect, the interval S1 and the length L1 have a relationship of 0.8≦S1/L1.
According to this, since the pair of conductive holding members are sufficiently separated from each other, even if the positions and sizes of the pair of conductive holding members vary due to manufacturing errors, short-circuiting of the pair of conductive holding members will cause problems. can be suppressed. In addition, since the holding position of the crystal oscillator is separated, it is possible to suppress the deterioration of the holding strength of the crystal oscillator, thereby suppressing the occurrence of defects due to damage such as dropout of the crystal oscillator.
　一態様として、水晶片の第２方向における幅Ｗ１と長さＬ１とは、０．５５≦Ｌ１／Ｗ１≦０．７５の関係を有する。
　０．５５≦Ｌ１／Ｗ１であれば、間隔Ｓ１と長さＬ１とがＳ１／Ｌ１≦１．５の関係を有している場合に、長さＬ１が充分に大きいため間隔Ｓ１も充分に大きくできる。したがって、一対の導電性保持部材が互いに充分に離間し、導電性保持部材同士の短絡や水晶振動子の損傷などの不具合の発生が抑制できる。Ｌ１／Ｗ１≦０．７５であれば、貫通孔が存在することによる水晶片の機械的強度の低下を抑制し、水晶振動素子の損傷による不具合の発生が抑制できる。また、貫通孔の両脇の水晶片に、充分な面積の上面及び下面が確保できるため、一対の引出電極の狭小化による断線等の不具合の発生が抑制できる。 As one aspect, the width W1 and the length L1 of the crystal piece in the second direction have a relationship of 0.55≦L1/W1≦0.75.
If 0.55≦L1/W1, when the distance S1 and the length L1 have a relationship of S1/L1≦1.5, the distance S1 is sufficiently large because the length L1 is sufficiently large. can. Therefore, the pair of conductive holding members are sufficiently spaced apart from each other, and problems such as a short circuit between the conductive holding members and damage to the crystal oscillator can be suppressed. If L1/W1≦0.75, it is possible to suppress the deterioration of the mechanical strength of the crystal piece due to the presence of the through-holes, and to suppress the occurrence of problems due to damage to the crystal vibrating element. In addition, since the crystal pieces on both sides of the through-hole can have sufficient areas of the upper surface and the lower surface, it is possible to suppress the occurrence of problems such as disconnection due to narrowing of the pair of extraction electrodes.
　一態様として、水晶片は、一対の励振電極が設けられた励振部と、水晶片の平面視における励振部の外側に位置する励振部よりも薄い周辺部とを有し、励振部の幅Ｗ２と間隔Ｓ１と長さＬ１と幅Ｗ１とは、Ｓ１＜Ｌ１＜Ｗ１＜Ｗ２の関係を有する。 As one aspect, the crystal piece has an excitation portion provided with a pair of excitation electrodes, and a peripheral portion that is thinner than the excitation portion and is located outside the excitation portion in plan view of the crystal piece, and the width of the excitation portion is W2 , the interval S1, the length L1, and the width W1 have a relationship of S1<L1<W1<W2.
　なお、本発明に係る実施形態は、水晶振動子に限定されるものではなく、他の圧電振動子（Ｐｉｅｚｏｅｌｅｃｔｒｉｃ　Ｒｅｓｏｎａｔｏｒ　Ｕｎｉｔ）にも適用可能である。本実施形態に係る圧電振動子に好適に用いられる圧電片としては、例えば、チタン酸ジルコン酸鉛（ＰＺＴ）や窒化アルミニウムなどの圧電セラミック、ニオブ酸リチウムやタンタル酸リチウムなどの圧電単結晶、を挙げることができるが、これらに限定されるものではなく適宜選択可能である。 It should be noted that the embodiments of the present invention are not limited to crystal oscillators, and can also be applied to other piezoelectric oscillators (Piezoelectric Resonator Unit). Piezoelectric pieces suitably used in the piezoelectric vibrator according to this embodiment include, for example, piezoelectric ceramics such as lead zirconate titanate (PZT) and aluminum nitride, and piezoelectric single crystals such as lithium niobate and lithium tantalate. However, it is not limited to these and can be selected as appropriate.
　本発明に係る実施形態は、タイミングデバイス、発音器、発振器、荷重センサなど、圧電効果により電気機械エネルギー変換を行うデバイスであれば、特に限定されることなく適宜適用可能である。 The embodiments according to the present invention are applicable without any particular limitation, such as timing devices, sound generators, oscillators, load sensors, and the like, as long as they are devices that perform electromechanical energy conversion by the piezoelectric effect.
　以上説明したように、本発明の一態様によれば、周波数変動が抑制可能な圧電振動子が提供できる。 As described above, according to one aspect of the present invention, it is possible to provide a piezoelectric vibrator capable of suppressing frequency fluctuations.
　なお、以上説明した実施形態は、本発明の理解を容易にするためのものであり、本発明を限定して解釈するためのものではない。本発明は、その趣旨を逸脱することなく、変更／改良され得るとともに、本発明にはその等価物も含まれる。即ち、各実施形態に当業者が適宜設計変更を加えたものも、本発明の特徴を備えている限り、本発明の範囲に包含される。例えば、各実施形態が備える各要素及びその配置、材料、条件、形状、サイズなどは、例示したものに限定されるわけではなく適宜変更することができる。また、各実施形態が備える各要素は、技術的に可能な限りにおいて組み合わせることができ、これらを組み合わせたものも本発明の特徴を含む限り本発明の範囲に包含される。 It should be noted that the embodiments described above are intended to facilitate understanding of the present invention, and are not intended to limit and interpret the present invention. The present invention may be modified/improved without departing from its spirit, and the present invention also includes equivalents thereof. In other words, any embodiment appropriately modified in design by a person skilled in the art is also included in the scope of the present invention as long as it has the features of the present invention. For example, each element provided in each embodiment and its arrangement, material, condition, shape, size, etc. are not limited to those illustrated and can be changed as appropriate. Moreover, each element provided in each embodiment can be combined as long as it is technically possible, and a combination thereof is also included in the scope of the present invention as long as it includes the features of the present invention.
　１…水晶振動子、
　１０…水晶振動素子、
　１１…水晶片、
　１４ａ，１４ｂ…励振電極、
　１５ａ，１５ｂ…引出電極、
　１６ａ，１６ｂ…接続電極、
　１７…励振部、
　１８…周辺部、
　３０…ベース部材、
　２０…貫通孔、
　３６ａ，３６ｂ…導電性保持部材
　４０…蓋部材、
　５０…接合部材。 1 ... crystal oscillator,
10 ... crystal oscillator,
11... crystal piece,
14a, 14b... excitation electrodes,
15a, 15b... Extraction electrodes,
16a, 16b ... connection electrodes,
17 ... excitation unit,
18... Peripheral part,
30 ... Base member,
20... Through hole,
36a, 36b... Conductive holding member 40... Lid member,
50 ... Joining member.

Claims (5)

  1. 　圧電片と、前記圧電片に設けられ互いに対向する一対の励振電極と、前記圧電片に設けられ前記一対の励振電極に電気的に接続された一対の接続電極とを有し、前記一対の接続電極は、前記圧電片の平面視における第１方向及び前記第１方向に交差する第２方向のうち前記第１方向の端部側に配置された、圧電振動素子と、
    　一対の電極パッドを有するベース部材と、
    　前記圧電振動素子の前記一対の接続電極と前記ベース部材の一対の電極パッドとを電気的に接続し、前記ベース部材の上方に前記圧電振動素子を保持する、一対の導電性保持部材と
    を備え、
    　前記第１方向における前記一対の励振電極と前記一対の接続電極との間の前記圧電片の領域には、前記圧電片を貫通する貫通孔が設けられ、
    　前記一対の導電性保持部材のそれぞれの縁部のうち前記第２方向における互いに最も離間する部分同士の間の間隔Ｓ１と、前記貫通孔の前記第２方向における長さＬ１とは、
    　Ｓ１／Ｌ１≦１．５
    の関係を有する、圧電振動子。     a piezoelectric piece, a pair of excitation electrodes provided on the piezoelectric piece and facing each other, and a pair of connection electrodes provided on the piezoelectric piece and electrically connected to the pair of excitation electrodes, a piezoelectric vibrating element in which the electrode is arranged on an end portion side of the first direction in a first direction in a plan view of the piezoelectric piece and a second direction intersecting the first direction;
    a base member having a pair of electrode pads;
    a pair of conductive holding members that electrically connect the pair of connection electrodes of the piezoelectric vibrating element and the pair of electrode pads of the base member and hold the piezoelectric vibrating element above the base member; ,
    a through hole penetrating through the piezoelectric piece is provided in a region of the piezoelectric piece between the pair of excitation electrodes and the pair of connection electrodes in the first direction,
    The distance S1 between the edges of the pair of conductive holding members that are the most distant from each other in the second direction and the length L1 of the through hole in the second direction are:
    S1/L1≤1.5
    A piezoelectric vibrator having a relationship of
  2. 　前記間隔Ｓ１と前記長さＬ１とは、
    　０．８≦Ｓ１／Ｌ１
    の関係を有する、
    　請求項１に記載の圧電振動子。     The interval S1 and the length L1 are
    0.8≦S1/L1
    having a relationship of
    The piezoelectric vibrator according to claim 1.
  3. 　前記圧電片の前記第２方向における幅Ｗ１と前記長さＬ１とは、
    　０．５５≦Ｌ１／Ｗ１≦０．７５
    の関係を有する、
    　請求項１又は２に記載の圧電振動子。     The width W1 and the length L1 of the piezoelectric piece in the second direction are
    0.55≦L1/W1≦0.75
    having a relationship of
    The piezoelectric vibrator according to claim 1 or 2.
  4. 　前記圧電片は、前記一対の励振電極が設けられた励振部と、前記圧電片の平面視における前記励振部の外側に位置する前記励振部よりも薄い周辺部とを有し、
    　前記励振部の幅Ｗ２と前記間隔Ｓ１と前記長さＬ１と前記幅Ｗ１とは、
    　Ｓ１＜Ｌ１＜Ｗ１＜Ｗ２
    の関係を有する、
    　請求項１から３のいずれか１項に記載の圧電振動子。     The piezoelectric piece has an excitation portion provided with the pair of excitation electrodes, and a peripheral portion that is located outside the excitation portion in plan view of the piezoelectric piece and is thinner than the excitation portion,
    The width W2, the interval S1, the length L1, and the width W1 of the excitation portion are
    S1<L1<W1<W2
    having a relationship of
    The piezoelectric vibrator according to any one of claims 1 to 3.
  5. 　前記圧電振動素子は水晶振動素子である、
    　請求項１から４のいずれか１項に記載の圧電振動子。     The piezoelectric vibrating element is a crystal vibrating element,
    The piezoelectric vibrator according to any one of claims 1 to 4.
PCT/JP2021/032789 2021-01-22 2021-09-07 Piezoelectric vibrator WO2022158028A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009188483A (en) * 2008-02-04 2009-08-20 Epson Toyocom Corp Piezoelectric device, and surface-mounted type piezoelectric oscillator
JP2012156592A (en) * 2011-01-21 2012-08-16 Seiko Epson Corp Piezoelectric vibration piece, piezoelectric vibrator and electronic device
JP2014007693A (en) * 2012-06-27 2014-01-16 Seiko Epson Corp Vibration element, vibrator, electronic device, electronic apparatus, and mobile body
JP2020053802A (en) * 2018-09-26 2020-04-02 株式会社村田製作所 Oscillation element and oscillator

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009188483A (en) * 2008-02-04 2009-08-20 Epson Toyocom Corp Piezoelectric device, and surface-mounted type piezoelectric oscillator
JP2012156592A (en) * 2011-01-21 2012-08-16 Seiko Epson Corp Piezoelectric vibration piece, piezoelectric vibrator and electronic device
JP2014007693A (en) * 2012-06-27 2014-01-16 Seiko Epson Corp Vibration element, vibrator, electronic device, electronic apparatus, and mobile body
JP2020053802A (en) * 2018-09-26 2020-04-02 株式会社村田製作所 Oscillation element and oscillator

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