WO2018043084A1 - 圧電振動子 - Google Patents

圧電振動子 Download PDF

Info

Publication number
WO2018043084A1
WO2018043084A1 PCT/JP2017/028960 JP2017028960W WO2018043084A1 WO 2018043084 A1 WO2018043084 A1 WO 2018043084A1 JP 2017028960 W JP2017028960 W JP 2017028960W WO 2018043084 A1 WO2018043084 A1 WO 2018043084A1
Authority
WO
WIPO (PCT)
Prior art keywords
substrate
filler
piezoelectric
conductive holding
holding member
Prior art date
Application number
PCT/JP2017/028960
Other languages
English (en)
French (fr)
Inventor
山本　裕之
Original Assignee
株式会社村田製作所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社村田製作所 filed Critical 株式会社村田製作所
Priority to JP2018537091A priority Critical patent/JP6956093B2/ja
Priority to CN201780052755.8A priority patent/CN109690941B/zh
Publication of WO2018043084A1 publication Critical patent/WO2018043084A1/ja
Priority to US16/283,011 priority patent/US11233497B2/en

Links

Images

Classifications

    • 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
    • H03H9/0504—Holders; Supports for bulk acoustic wave devices
    • H03H9/0509—Holders; Supports for bulk acoustic wave devices consisting of adhesive elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L24/28—Structure, shape, material or disposition of the layer connectors prior to the connecting process
    • H01L24/29—Structure, shape, material or disposition of the layer connectors prior to the connecting process of an individual layer connector
    • 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
    • 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 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/02—Bonding areas; Manufacturing methods related thereto
    • H01L2224/04—Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L2224/05—Structure, shape, material or disposition of the bonding areas prior to the connecting process of an individual bonding area
    • H01L2224/05001—Internal layers
    • H01L2224/05099—Material
    • H01L2224/051—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
    • H01L2224/05163—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof the principal constituent melting at a temperature of greater than 1550°C
    • H01L2224/05171—Chromium [Cr] as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/02—Bonding areas; Manufacturing methods related thereto
    • H01L2224/04—Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L2224/05—Structure, shape, material or disposition of the bonding areas prior to the connecting process of an individual bonding area
    • H01L2224/0554—External layer
    • H01L2224/05599—Material
    • H01L2224/056—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
    • H01L2224/05638—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
    • H01L2224/05644—Gold [Au] as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/12—Structure, shape, material or disposition of the bump connectors prior to the connecting process
    • H01L2224/13—Structure, shape, material or disposition of the bump connectors prior to the connecting process of an individual bump connector
    • H01L2224/13001—Core members of the bump connector
    • H01L2224/13099—Material
    • H01L2224/13198—Material with a principal constituent of the material being a combination of two or more materials in the form of a matrix with a filler, i.e. being a hybrid material, e.g. segmented structures, foams
    • H01L2224/13199—Material of the matrix
    • H01L2224/1329—Material of the matrix with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/12—Structure, shape, material or disposition of the bump connectors prior to the connecting process
    • H01L2224/13—Structure, shape, material or disposition of the bump connectors prior to the connecting process of an individual bump connector
    • H01L2224/13001—Core members of the bump connector
    • H01L2224/13099—Material
    • H01L2224/13198—Material with a principal constituent of the material being a combination of two or more materials in the form of a matrix with a filler, i.e. being a hybrid material, e.g. segmented structures, foams
    • H01L2224/13298—Fillers
    • H01L2224/13299—Base material
    • H01L2224/133—Base material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
    • H01L2224/13338—Base material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
    • H01L2224/13339—Silver [Ag] as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/12—Structure, shape, material or disposition of the bump connectors prior to the connecting process
    • H01L2224/13—Structure, shape, material or disposition of the bump connectors prior to the connecting process of an individual bump connector
    • H01L2224/13001—Core members of the bump connector
    • H01L2224/13099—Material
    • H01L2224/13198—Material with a principal constituent of the material being a combination of two or more materials in the form of a matrix with a filler, i.e. being a hybrid material, e.g. segmented structures, foams
    • H01L2224/13298—Fillers
    • H01L2224/13299—Base material
    • H01L2224/1339—Base material with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
    • H01L2224/13391—The principal constituent being an elastomer, e.g. silicones, isoprene, neoprene
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/12—Structure, shape, material or disposition of the bump connectors prior to the connecting process
    • H01L2224/14—Structure, shape, material or disposition of the bump connectors prior to the connecting process of a plurality of bump connectors
    • H01L2224/141—Disposition
    • H01L2224/1412—Layout
    • H01L2224/1413—Square or rectangular array
    • H01L2224/14134—Square or rectangular array covering only portions of the surface to be connected
    • H01L2224/14135—Covering only the peripheral area of the surface to be connected, i.e. peripheral arrangements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/15—Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L2224/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
    • H01L2224/161—Disposition
    • H01L2224/16151—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/16221—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/16225—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/28—Structure, shape, material or disposition of the layer connectors prior to the connecting process
    • H01L2224/29—Structure, shape, material or disposition of the layer connectors prior to the connecting process of an individual layer connector
    • H01L2224/29001—Core members of the layer connector
    • H01L2224/29099—Material
    • H01L2224/29198—Material with a principal constituent of the material being a combination of two or more materials in the form of a matrix with a filler, i.e. being a hybrid material, e.g. segmented structures, foams
    • H01L2224/29298—Fillers
    • H01L2224/29299—Base material
    • H01L2224/293—Base material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
    • H01L2224/29338—Base material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
    • H01L2224/29339—Silver [Ag] as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/28—Structure, shape, material or disposition of the layer connectors prior to the connecting process
    • H01L2224/29—Structure, shape, material or disposition of the layer connectors prior to the connecting process of an individual layer connector
    • H01L2224/29001—Core members of the layer connector
    • H01L2224/29099—Material
    • H01L2224/29198—Material with a principal constituent of the material being a combination of two or more materials in the form of a matrix with a filler, i.e. being a hybrid material, e.g. segmented structures, foams
    • H01L2224/29298—Fillers
    • H01L2224/29299—Base material
    • H01L2224/2939—Base material with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
    • H01L2224/29391—The principal constituent being an elastomer, e.g. silicones, isoprene, neoprene
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/10—Bump connectors ; Manufacturing methods related thereto
    • H01L24/12—Structure, shape, material or disposition of the bump connectors prior to the connecting process
    • H01L24/13—Structure, shape, material or disposition of the bump connectors prior to the connecting process of an individual bump connector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/10—Bump connectors ; Manufacturing methods related thereto
    • H01L24/12—Structure, shape, material or disposition of the bump connectors prior to the connecting process
    • H01L24/14—Structure, shape, material or disposition of the bump connectors prior to the connecting process of a plurality of bump connectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/10—Bump connectors ; Manufacturing methods related thereto
    • H01L24/15—Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L24/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
    • H01L2924/161—Cap
    • H01L2924/1615—Shape
    • H01L2924/16152—Cap comprising a cavity for hosting the device, e.g. U-shaped cap

Definitions

  • the present invention relates to a piezoelectric vibrator, and more particularly, to a piezoelectric vibrator in which a piezoelectric vibration element is held on a substrate by a conductive holding member.
  • Patent Document 1 discloses a piezoelectric device in which a spherical spacer coated with a metal of a good conductor is mixed in an adhesive that holds a piezoelectric vibrating piece.
  • the piezoelectric vibration element includes a piezoelectric substrate and excitation electrodes provided on both main surfaces of the piezoelectric substrate.
  • vibration is attenuated as it approaches an outer edge of a piezoelectric substrate from an excitation portion sandwiched between excitation electrodes.
  • the piezoelectric vibrator is downsized, not only in the vicinity of the outer edge of the piezoelectric vibration element (that is, in the region where the vibration is attenuated) but also in the adhesion between the piezoelectric vibration element and the main surface of the substrate, The adhesive is also applied to a portion close to the excitation portion (that is, a region where vibration is not sufficiently damped).
  • the piezoelectric device as disclosed in Patent Document 1 has a problem in that the vibration is hindered by the adhesive bonded to the portion near the excitation portion of the piezoelectric vibration element, and the characteristics of the piezoelectric vibrator deteriorate. .
  • the present invention has been made in view of such circumstances, and an object thereof is to provide a piezoelectric vibrator in which deterioration of vibrator characteristics is suppressed even when the piezoelectric vibrator is downsized.
  • a piezoelectric vibrator includes a piezoelectric vibration element, a substrate having first and second main surfaces facing each other, and a conductivity that holds the piezoelectric vibration element on the first main surface of the substrate in an excitable manner.
  • a holding member, and the conductive holding member includes a first filler having a conductive material as a main component, and a second filler having an insulating material as a main component and having a Young's modulus smaller than that of the first filler.
  • the second filler is arranged in a denser state in the outer peripheral region of the conductive holding member than in the central region of the conductive holding member in a plan view viewed from the normal direction of the first main surface of the substrate.
  • the value of the Young's modulus in the outer peripheral region of the conductive holding member is smaller than that in the central region. Therefore, the outer peripheral region (that is, a relatively soft region) of the conductive holding member is joined to a portion close to the excitation portion of the piezoelectric vibration element (that is, a region where vibration is not sufficiently attenuated). Therefore, the influence on the vibration due to the joining of the conductive holding member is reduced, and the deterioration of the vibrator characteristics of the piezoelectric vibrator is suppressed.
  • a piezoelectric vibrator includes a piezoelectric vibration element, a substrate having first and second main surfaces facing each other, and a conductivity that holds the piezoelectric vibration element on the first main surface of the substrate in an excitable manner.
  • a holding member, and the conductive holding member includes a first filler containing a conductive material as a main component, and a second filler containing an insulating material as a main component and having a Young's modulus smaller than that of the first filler.
  • the ratio H1 of the volume of the first filler to the volume of the second filler in the central region of the conductive holding member in a plan view viewed from the normal direction of the first main surface of the substrate is the conductive holding member
  • the ratio of the volume of the first filler to the volume of the second filler in the outer peripheral region is higher than H2.
  • the value of the Young's modulus in the outer peripheral region of the conductive holding member is smaller than that in the central region. Therefore, the outer peripheral region (that is, a relatively soft region) of the conductive holding member is joined to a portion close to the excitation portion of the piezoelectric vibration element (that is, a region where vibration is not sufficiently attenuated). Therefore, the influence on the vibration due to the joining of the conductive holding member is reduced, and the deterioration of the vibrator characteristics of the piezoelectric vibrator is suppressed.
  • the present invention it is possible to provide a piezoelectric vibrator in which deterioration of vibrator characteristics is suppressed even when the piezoelectric vibrator is downsized.
  • FIG. 1 is an exploded perspective view of a piezoelectric vibrator according to an embodiment of the present invention.
  • 2 is a cross-sectional view taken along line II-II in FIG.
  • FIG. 3 is a diagram schematically showing a top view of the conductive holding member.
  • FIG. 4 is a photomicrograph of the conductive holding member.
  • FIG. 5 is a plan view of a piezoelectric vibrator according to an embodiment of the present invention.
  • FIG. 1 is an exploded perspective view of a piezoelectric vibrator according to an embodiment of the present invention
  • FIG. 2 is a sectional view taken along line II-II in FIG.
  • the piezoelectric vibrator 1 includes a piezoelectric vibration element 100 (Piezoelectric Resonator), a lid member 200, and a substrate 300.
  • the lid member 200 and the substrate 300 are part of the structure of a holder (case or package) for housing the piezoelectric vibration element 100.
  • the piezoelectric vibration element 100 includes a piezoelectric substrate 110 and excitation electrodes (Excitation Electrodes) 120 and 130 (hereinafter referred to as “first excitation electrode 120” and “second excitation electrode 130”) provided on the front and back surfaces of the piezoelectric substrate 110, respectively. Also).
  • excitation electrodes 120 and 130 hereinafter referred to as “first excitation electrode 120” and “second excitation electrode 130”
  • the piezoelectric substrate 110 is formed from a predetermined piezoelectric material, and the material is not particularly limited. In the example shown in FIG. 1, the piezoelectric substrate 110 is formed from a quartz material having a predetermined crystal orientation.
  • the piezoelectric substrate 110 is, for example, an AT-cut crystal piece (Quartz Crystal Element).
  • the AT-cut crystal piece is 35 degrees 15 minutes in the direction from the Y axis to the Z axis around the X axis among the X, Y, and Z axes that are the crystal axes of the artificial quartz.
  • the piezoelectric substrate 110 which is an AT-cut crystal piece has a long side extending along the X axis, a short side extending along the Z ′ axis, and a thickness extending along the Y ′ axis. And has a substantially rectangular shape on the XZ ′ plane.
  • a piezoelectric vibration element using an AT-cut crystal piece has high frequency stability over a wide temperature range, and is excellent in aging characteristics.
  • a piezoelectric vibration element using an AT-cut crystal piece that is, a quartz vibration element
  • the piezoelectric substrate is not limited to the above configuration, and for example, a rectangular AT-cut quartz piece having a long side extending along the Z ′ axis and a short side extending along the X axis is applied. May be.
  • a crystal piece with a cut other than the AT cut such as a BT cut may be used.
  • the material of the piezoelectric substrate is not limited to quartz, and for example, a piezoelectric ceramic such as PZT or other piezoelectric material such as zinc oxide may be used.
  • the piezoelectric vibration element may be, for example, a MEMS (Micro Electro Mechanical Systems), and specifically, Si-MEMS in which a MEMS is formed on a silicone substrate may be used. Furthermore, the piezoelectric vibration element may be a piezoelectric MEMS using a predetermined piezoelectric material such as AlN, LiTaO 3 , LiNbO 3 , or PZT.
  • MEMS Micro Electro Mechanical Systems
  • Si-MEMS Si-MEMS in which a MEMS is formed on a silicone substrate may be used.
  • the piezoelectric vibration element may be a piezoelectric MEMS using a predetermined piezoelectric material such as AlN, LiTaO 3 , LiNbO 3 , or PZT.
  • the first excitation electrode 120 is formed on the first main surface 112 of the piezoelectric substrate 110
  • the second excitation electrode 130 is formed on the second main surface 114 of the piezoelectric substrate 110.
  • the first excitation electrode 120 and the second excitation electrode 130 are a pair of electrodes, and are disposed so as to substantially overlap each other when the XZ ′ plane is viewed in plan.
  • the piezoelectric substrate 110 has an excitation portion sandwiched between the first excitation electrode 120 and the second excitation electrode 130.
  • the piezoelectric substrate 110 has a connection electrode 124 electrically connected to the first excitation electrode 120 via the extraction electrode 122, and a connection electrode 134 electrically connected to the second excitation electrode 130 via the extraction electrode 132. And are formed. Specifically, the extraction electrode 122 is extracted from the first excitation electrode 120 toward the short side of the X-axis negative direction side on the first main surface 112 and further passes through the side surface of the piezoelectric substrate 110 on the Z′-axis positive direction side. Thus, the connection electrode 124 formed on the second main surface 114 is connected.
  • the extraction electrode 132 is extracted from the second excitation electrode 130 toward the X-axis negative direction side short side on the second main surface 114 and connected to the connection electrode 134 formed on the second main surface 114.
  • the connection electrodes 124 and 134 are arranged along the short side of the X-axis negative direction, and are electrically held and mechanically held on the substrate 300 via conductive holding members 340 and 342 described later.
  • the arrangement and pattern shape of the connection electrodes 124 and 134 and the extraction electrodes 122 and 132 are not limited, and may be changed as appropriate in consideration of electrical connection with other members.
  • Each of the electrodes including the first excitation electrode 120 and the second excitation electrode 130 has, for example, a chromium (Cr) layer formed on the surface of the piezoelectric substrate 110 as a base to increase the bonding force, and a gold layer on the surface of the chromium layer.
  • An (Au) layer is formed.
  • the material is not limited.
  • the lid member 200 has a recess that opens to face the first main surface 302 of the substrate 300.
  • the lid member 200 is provided with a side wall portion 202 formed so as to rise from the bottom surface of the recess over the entire circumference of the opening.
  • the side wall portion 202 is an end surface 204 facing the first main surface 302 of the substrate 300. have.
  • the end surface 204 is bonded to the first main surface 302 of the substrate 300 via the bonding material 250.
  • the lid member 200 may have any shape that can accommodate the piezoelectric vibration element 100 in the internal space when bonded to the substrate 300, and the shape is not particularly limited.
  • the material of the lid member 200 is not particularly limited, but may be made of a conductive material such as metal.
  • a shield function can be added by electrically connecting the lid member 200 to the ground potential.
  • the lid member 200 may be made of an alloy (for example, 42 alloy) containing iron (Fe) and nickel (Ni).
  • a surface layer such as a gold (Au) layer may be further formed on the surface of the lid member 200. By forming a gold layer on the surface, it is possible to prevent the lid member 200 from being oxidized.
  • the lid member 200 may be an insulating material or a composite structure of a conductive material and an insulating material.
  • the substrate 300 holds the piezoelectric vibration element 100 in an excitable manner.
  • the piezoelectric vibration element 100 is held on the first main surface 302 of the substrate 300 through the conductive holding members 340 and 342 so as to be able to be excited.
  • the substrate 300 has a long side extending along the X axis, a short side extending along the Z ′ axis, and a side in the thickness direction extending along the Y ′ axis, and is substantially rectangular on the XZ ′ plane. It has a shape.
  • the substrate 300 is made of, for example, a single layer of insulating ceramic. As another embodiment, the substrate 300 may be formed by stacking and firing a plurality of insulating ceramic sheets.
  • the substrate 300 is preferably made of a heat resistant material.
  • the substrate 300 may have a flat plate shape as shown in FIG. 1, or may have a concave shape opened in a direction facing the lid member 200.
  • connection electrodes 320 and 322, corner electrodes 324 and 326, and extraction electrodes 320a and 322a are formed on the first main surface 302, and side electrodes 330, 332, 334, and 336 are formed on the side surfaces.
  • External electrodes 360, 362, 364, 366 are formed on the main surface 304.
  • connection electrodes 320 and 322 are formed on the first main surface 302 of the substrate 300 along the short side on the X axis negative direction side and spaced from the short side.
  • the connection electrode 320 is connected to the connection electrode 124 of the piezoelectric vibration element 100 via the conductive holding member 340
  • the connection electrode 322 is connected to the connection electrode 134 of the piezoelectric vibration element 100 via the conductive holding member 342.
  • the material of the connection electrodes 320 and 322 is not particularly limited.
  • the connection electrodes 320 and 322 are formed of a laminate of molybdenum (Mo), nickel (Ni), and gold (Au). Details of the configuration of the conductive holding members 340 and 342 will be described later.
  • the extraction electrode 320 a is extracted from the connection electrode 320 toward the side electrode 330 provided at one corner of the substrate 300.
  • the extraction electrode 322a is extracted along the X-axis direction from the connection electrode 322 toward the side electrode 332 provided at the corner of the substrate 300 at the diagonal position of the side electrode 330.
  • corner electrodes 324 and 326 are formed in the remaining corners (corners other than the corners where the extraction electrodes 320a and 322a electrically connected to the connection electrodes 320 and 322 are disposed). .
  • the corner electrodes 324 and 326 are electrodes that are not electrically connected to either the first excitation electrode 120 or the second excitation electrode 130.
  • the plurality of side surface electrodes 330, 332, 334, and 336 are formed on the side surfaces near the respective corners of the substrate 300. Further, the plurality of external electrodes 360, 362, 364, 366 are formed in the vicinity of each corner on the second main surface 304 of the substrate 300. Specifically, the side electrode 330 and the external electrode 360 are arranged at corners on the X axis negative direction and the Z ′ axis positive direction side, and the side electrode 332 and the external electrode 362 are on the X axis positive direction and the Z ′ axis negative direction side.
  • the side electrode 334 and the external electrode 364 are arranged at the corners on the X axis positive direction and the Z ′ axis positive direction side, and the side electrode 336 and the external electrode 366 are arranged on the X axis negative direction and the Z ′ axis negative direction. It is arranged at the corner on the direction side.
  • Side electrodes 330, 332, 334, and 336 are provided to electrically connect the electrodes on the first main surface 302 and the second main surface 304.
  • a corner portion of the substrate 300 has a cut-out side surface formed by cutting a part of the corner portion into a cylindrical curved surface shape (also referred to as a castellation shape).
  • Side electrodes 330, 332, 334, and 336 are formed on the side surfaces.
  • the shape of the corner portion of the substrate 300 is not limited to this, and the shape of the cutout may be a flat shape, or may be a rectangular shape having no cutout and having four corners at right angles in plan view. There may be.
  • External electrodes 360, 362, 364, and 366 are electrodes for electrical connection with a mounting board (not shown).
  • the external electrodes 360, 362, 364, and 366 are electrically connected to side electrodes 330, 332, 334, and 336 formed on the side surfaces of the corresponding corners, respectively.
  • the external electrodes 360, 362, 364, and 366 can be electrically connected to the electrodes on the first main surface 302 side of the substrate 300 via the side electrodes 330, 332, 334, and 336.
  • the external electrode 360 is electrically connected to the first excitation electrode 120 via the side electrode 330, the extraction electrode 320a, the connection electrode 320, and the conductive holding member 340.
  • the external electrode 362 is electrically connected to the second excitation electrode 130 via the side electrode 332, the extraction electrode 322a, the connection electrode 322, and the conductive holding member 342. That is, the external electrodes 360 and 362 are input / output terminals that are electrically connected to the first excitation electrode 120 or the second excitation electrode 130.
  • the remaining external electrodes 364 and 366 are dummy electrodes that are not electrically connected to the first excitation electrode 120 or the second excitation electrode 130 of the piezoelectric vibration element 100.
  • the external electrodes 364 and 366 can be formed at all corners, so that the process of electrically connecting the piezoelectric vibrator 1 to another member is facilitated.
  • the external electrodes 364 and 366 may function as a grounding electrode to which a ground potential is supplied.
  • the lid member 200 when the lid member 200 is made of a conductive material, the lid member 200 can be provided with a shielding function by electrically connecting the lid member 200 to the external electrodes 364 and 366 that are grounding electrodes.
  • each structure of the connection electrode, the corner electrode, the extraction electrode, the side electrode, and the external electrode formed on the substrate 300 is not limited to the above-described example, and various modifications can be applied.
  • the number of external electrodes is not limited to four.
  • only two input / output terminals arranged diagonally may be provided.
  • the side electrodes are not limited to those arranged at the corners, and may be formed on any side surface of the substrate 300 excluding the corners. In this case, as already described, a cut-out side surface in which a part of the side surface is cut into a cylindrical curved surface may be formed, and a side electrode may be formed on the side surface excluding the corners.
  • corner electrodes 324 and 326, the side surface electrodes 334 and 336, and the external electrodes 364 and 366 may not be formed.
  • a through hole penetrating from the first main surface 302 to the second main surface 304 is formed in the substrate 300, and electrical conduction is made from the connection electrode formed on the first main surface 302 to the second main surface 304 by this through hole. You may plan.
  • the bonding material 250 is provided over the entire circumferences of the lid member 200 and the substrate 300, and bonds the end surface 204 of the side wall portion 202 of the lid member 200 and the first main surface 302 of the substrate 300.
  • the material of the bonding material 250 is not limited, but may be, for example, a gold (Au) -tin (Sn) eutectic alloy.
  • the piezoelectric vibration element 100 is hermetically sealed in an internal space (cavity) surrounded by the concave portion of the lid member 200 and the substrate 300.
  • the pressure in the internal space is a vacuum state lower than the atmospheric pressure, thereby reducing a change with time due to oxidation of the first excitation electrode 120 and the second excitation electrode 130.
  • the piezoelectric vibrator 1 an alternating electric field is applied between the pair of first excitation electrode 120 and second excitation electrode 130 in the piezoelectric vibration element 100 via the external electrodes 360 and 362 of the substrate 300.
  • FIG. 3 is a diagram schematically showing a top view of the conductive holding member
  • FIG. 4 is a photomicrograph of the conductive holding member.
  • FIG. 3 shows the conductive holding member 342 provided on the connection electrode 322 in plan view from the normal direction (Y′-axis direction) of the first main surface 302 of the substrate 300 (that is, XZ ′).
  • FIG. 2 schematically shows a top view of the surface in plan view.
  • the connection electrode 322 is shown in a rectangular shape for convenience of explanation, but the shape of the connection electrode is not limited to this.
  • the conductive holding member 342 is formed, for example, by thermally curing an adhesive.
  • the conductive holding member 342 holds the piezoelectric vibration element 100 in an excitable manner and electrically connects the connection electrode 134 formed on the piezoelectric vibration element 100 and the connection electrode 322 formed on the substrate 300.
  • the conductive holding member 342 has, for example, a circular shape in a plan view of the XZ ′ plane.
  • the circular shape includes a circular shape or an elliptical shape.
  • the conductive holding member 342 may have other shapes such as a rectangular shape in a plan view of the XZ ′ plane. As shown in FIGS.
  • the conductive holding member 342 includes an adhesive (binder) 400, a plurality of spherical spacers 410 (second filler) and a plurality of metal particles 420 mixed in the adhesive 400.
  • the adhesive 400 contains, for example, a resin as a main component.
  • Each of the plurality of spherical spacers 410 has a spherical shape mainly composed of a resin such as a rubber having elasticity or a plastic such as a silicone resin.
  • the spherical shape includes a sphere and an ellipsoid.
  • the spherical spacer 410 is not covered with metal, and the resin material is exposed on the surface.
  • Such a spherical spacer has a smaller Young's modulus and lower acoustic impedance than a spherical spacer coated with metal.
  • the spherical spacer 410 has a smaller Young's modulus value and lower acoustic impedance than the metal particle 420.
  • Each of the plurality of metal particles 420 is a particle formed by bonding a plurality of metal atoms.
  • the material of the some metal particle 420 is not specifically limited, For example, it is silver (Ag) etc.
  • the plurality of metal particles 420 are cured while being in contact with each other inside the adhesive 400, whereby the holding member has conductivity.
  • the particle diameter of the metal particles 420 is formed by, for example, the spherical spacer 410 so that each of the plurality of metal particles 420 enters a gap formed by the plurality of spherical spacers 410 arranged on the connection electrode 322. Smaller than the gap.
  • the piezoelectric vibration element 100 has a predetermined interval from the first main surface 302 of the substrate 300, that is, an interval (for example, about 10 ⁇ m) corresponding to two steps of the outer dimension (for example, about 6 ⁇ m) of the spherical spacer 410. It will be held empty. Therefore, the distance between the second main surface 114 of the piezoelectric vibration element 100 and the first main surface 302 of the substrate 300 is kept constant, and the magnitude of the parasitic capacitance generated between the electrodes formed on both the main surfaces is constant. Can be kept in.
  • the number of spherical spacers to be stacked is not limited to this, and may be one or three or more.
  • the piezoelectric vibration element 100 generally attenuates vibration as it approaches the outer edge of the piezoelectric substrate 110 from the excitation portion. Therefore, if the conductive holding member is uniformly hard, the conductive material is exposed to a portion close to the excitation portion of the piezoelectric vibration element, specifically, a region where the vibration is not sufficiently attenuated as the piezoelectric vibrator is downsized. A holding member is joined and vibration can be inhibited by the conductive holding member. Specifically, for example, vibration can leak from the piezoelectric vibration element 100 to the substrate 300 via the conductive holding member.
  • the spherical spacer 410 has a conductive holding member 342 in a plan view from the normal direction (Y′-axis direction) of the first main surface 302 of the substrate 300.
  • the metal particles 420 are more densely arranged in the central region Rin than the outer peripheral region Rout of the conductive holding member 342.
  • the ratio H1 of the volume of the metal particles 420 to the volume of the spherical spacer 410 in the central region Rin of the conductive holding member 342 is equal to the ratio of the metal particles 420 in the outer peripheral region Rout of the conductive holding member 342.
  • the ratio of the volume to the volume of the spherical spacer 410 is higher than H2. Further, as described above, the spherical spacer 410 is softer than the metal particle 420. As a result, in the conductive holding member 342, the hard metal particles 420 are dense in the central region Rin, and the soft spherical spacers 410 are dense in the outer peripheral region Rout. Therefore, the outer peripheral region Rout is softer than the central region Rin. Become.
  • FIG. 4 shows a microscope viewed from the normal direction (Y′-axis direction) of the first main surface 302 of the substrate 300 after the piezoelectric vibration element 100 is peeled from the conductive holding member 342 to which the piezoelectric vibration element 100 is bonded. It is a photograph.
  • the spherical spacer 410 is shown as a white circle so that the spherical spacer 410 is clear.
  • the connection electrode 322 has a circular shape.
  • the spherical spacer 410 is denser in the outer peripheral region than in the central region of the conductive holding member 342.
  • spherical spacers 410 are arranged adjacent to each other so as to surround the central region.
  • a relatively soft outer periphery of the conductive holding members 340 and 342 is provided in a portion close to the excitation portion of the piezoelectric vibration element 100, specifically, in a region where vibration is not sufficiently damped.
  • the region Rout is joined, and a relatively hard central region Rin of the conductive holding members 340 and 342 is joined to the vicinity of the outer edge of the piezoelectric vibration element 100, specifically, the region where the vibration is attenuated ( (See FIG. 2).
  • the conductive holding members 340 and 342 have less influence of bonding on the vibrator characteristics than an adhesive having a uniform Young's modulus.
  • the outer peripheral region Rout of the conductive holding members 340 and 342 is relatively soft and has low acoustic impedance. Therefore, in a region where the vibration of the piezoelectric vibration element 100 is not sufficiently attenuated, the conductive holding members 340 and 342 having a relatively low acoustic impedance are joined to the piezoelectric vibration element 100 and the substrate 300 having a relatively high acoustic impedance. Therefore, a large difference in acoustic impedance can be taken. As a result, the reflected wave at the boundary surface between the piezoelectric vibration element 100 and the conductive holding members 340 and 342 increases and the transmitted wave decreases compared to the case where a uniformly hard adhesive is used.
  • Vibrations leaking to the substrate 300 through the conductive holding members 340 and 342 are reduced. Therefore, the inhibition of vibration caused by the joining of the conductive holding member can be reduced, and the equivalent series resistance (ESR) corresponding to the loss component of vibration energy can be reduced. Therefore, deterioration of the characteristics of the piezoelectric vibrator is suppressed.
  • ESR equivalent series resistance
  • the conductive holding members 340 and 342 can be bonded to a portion close to the excitation portion of the piezoelectric vibration element 100, the bonding area between the conductive holding members 340 and 342 and the piezoelectric vibration element 100 increases. . Therefore, even if the piezoelectric vibrator is downsized, it is possible to improve the bonding strength while suppressing the deterioration of the characteristics of the piezoelectric vibrator.
  • the ratio H1 of the volume of the metal particles 420 to the volume of the spherical spacer 410 in the central region Rin of the conductive holding members 340 and 342 is equal to the volume of the metal particles 420 in the outer peripheral region Rout of the conductive holding members 340 and 342.
  • the ratio to the volume of the spherical spacer 410 is higher than H2.
  • the metal particles 420 are mainly composed of a conductive material, and the spherical spacers 410 are mainly composed of an insulating material. Therefore, the conductivity per unit area of the central region Rin is improved, and the reliability of the conductivity of the conductive holding members 340 and 342 is improved.
  • the manufacturing cost is lower than that in the configuration in which the spherical spacer is coated with metal.
  • the piezoelectric vibration element 100 has one end fixed by the conductive holding members 340 and 342 and the other end is free. It may be fixed to the substrate 300 at both ends. That is, one of the connection electrodes 320, 322 is formed on the X axis positive direction side and the other is formed on the X axis negative direction side. Also good.
  • the arrangement of the spherical spacer 410 and the metal particle 420 is not limited to the above-described configuration.
  • the metal particles may be arranged uniformly in the conductive holding member, and the spherical spacers may be arranged more densely than the central region in the outer peripheral region of the conductive holding member.
  • FIG. 5 is a plan view of a piezoelectric vibrator according to an embodiment of the present invention.
  • FIG. 5 is a diagram in which the lid member 200 and the bonding material 250 in the piezoelectric vibrator 1 shown in FIG. 1 are omitted.
  • the outer peripheral region Rout of the conductive holding members 340 and 342 A part of the piezoelectric vibration element 100 is disposed outside the outer edge.
  • the central region Rin having a relatively large Young's modulus value in the conductive holding members 340 and 342 is joined to the vicinity of the outer edge of the piezoelectric vibration element 100.
  • the vibration is sufficiently attenuated in the vicinity of the outer edge of the piezoelectric vibration element 100, the influence of the bonding of the conductive holding members 340 and 342 on the vibration of the piezoelectric vibration element 100 is small. Therefore, deterioration of the vibrator characteristics of the piezoelectric vibrator is suppressed.
  • the conductive holding members 340 and 342 include a plurality of metal particles 420 and a plurality of spherical spacers 410 having a Young's modulus smaller than that of the plurality of metal particles, and a plan view of the XZ ′ plane.
  • the spherical spacers 410 are arranged in a dense state in the outer peripheral region Rout rather than the central region Rin of the conductive holding members 340 and 342.
  • a soft outer peripheral region Rout of the conductive holding members 340 and 342 is bonded to a portion close to the excitation portion of the piezoelectric vibration element 100 (that is, a region where vibration is not sufficiently attenuated) compared to the central region Rin.
  • the Rukoto Therefore, vibration leaking from the piezoelectric vibration element 100 to the substrate 300 via the conductive holding members 340 and 342 is reduced, and deterioration of vibrator characteristics of the piezoelectric vibrator 1 is suppressed. Further, since the bonding area between the conductive holding members 340 and 342 and the piezoelectric vibration element 100 is increased, the bonding strength is improved.
  • the metal particles 420 are densely arranged in the central region Rin rather than the outer peripheral region Rout of the conductive holding members 340 and 342 in the plan view of the XZ ′ plane of the conductive holding members 340 and 342. The Thereby, the electroconductivity per unit area of the center area
  • the ratio H1 of the volume of the metal particles 420 to the volume of the spherical spacer 410 in the central region Rin of the conductive holding members 340 and 342 is the spherical spacer of the volume of the metal particles 420 in the outer peripheral region Rout.
  • the ratio to the volume of 410 is higher than H2. Accordingly, a soft outer peripheral region Rout of the conductive holding members 340 and 342 is bonded to a portion close to the excitation portion of the piezoelectric vibration element 100 (that is, a region where vibration is not sufficiently attenuated) compared to the central region Rin.
  • the Rukoto is bonded to a portion close to the excitation portion of the piezoelectric vibration element 100 (that is, a region where vibration is not sufficiently attenuated) compared to the central region Rin.
  • the piezoelectric vibrator 1 a part of the outer peripheral region Rout of the conductive holding members 340 and 342 is arranged outside the outer edge of the piezoelectric vibration element 100 in the plan view of the XZ ′ plane.
  • the central region Rin having a relatively large Young's modulus in the conductive holding members 340 and 342 is joined to the vicinity of the outer edge of the piezoelectric vibration element 100 in which vibration is sufficiently damped. Accordingly, the bonding of the conductive holding members 340 and 342 has little influence on the vibration of the piezoelectric vibration element 100 and the deterioration of the vibrator characteristics of the piezoelectric vibrator 1 is suppressed.
  • the piezoelectric vibration element 100 is held at a predetermined interval from the first main surface 302 of the substrate 300 due to the mixture of the spherical spacers 410. Therefore, the magnitude of the parasitic capacitance generated between the electrodes formed on the second main surface 114 of the piezoelectric vibration element 100 and the first main surface 302 of the substrate 300 can be kept constant.
  • the material of the metal particles 420 is not particularly limited, but for example, silver may be the main component.
  • the material of the spherical spacer 410 is not particularly limited, but, for example, a silicone resin may be a main component.
  • each embodiment described above is for facilitating understanding of the present invention, and is not intended to limit the present invention.
  • the present invention can be changed / improved without departing from the spirit thereof, and the present invention includes equivalents thereof. That is, those in which the person skilled in the art appropriately changes the design of each embodiment is also included in the scope of the present invention as long as the features of the present invention are included.
  • each element included in each embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be changed as appropriate.
  • each element included in each embodiment can be combined as much as technically possible, and combinations thereof are included in the scope of the present invention as long as they include the features of the present invention.
  • Piezoelectric vibrator 100 Piezoelectric vibration element 110 Piezoelectric substrate 120,130 Excitation electrode 122,132 Extraction electrode 124,134 Connection electrode 200 Lid member 250 Bonding material 300 Substrate 320,322 Connection electrode 320a, 322a Extraction electrode 324,326 Corner electrode 330 , 332, 334, 336 Side electrode 340, 342 Conductive holding member 360, 362, 364, 366 External electrode 400 Adhesive 410 Spherical spacer 420 Metal particle Rin Central region Rout Outer peripheral region

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)

Abstract

圧電振動子（１）は、圧電振動素子（１００）と、対向する第１及び第２主面（３０２，３０４）を有する基板（３００）と、圧電振動素子（１００）を基板（３００）の第１主面（３０２）上に励振可能に保持する導電性保持部材（３４０，３４２）と、を備え、導電性保持部材（３４０，３４２）は、導電性材料を主成分とする第１フィラー（４２０）と、絶縁性材料を主成分とするとともに当該第１フィラーよりもヤング率の値が小さい第２フィラー（４１０）と、を含み、基板の第１主面（３０２）の法線方向からの平面視において、導電性保持部材（３４０，３４２）の中央領域（Ｒｉｎ）よりも、導電性保持部材（３４０，３４２）の外周領域（Ｒｏｕｔ）において第２フィラー（４１０）が密状態に配置される。

Description

圧電振動子
　本発明は、圧電振動子に関し、特に、圧電振動素子が導電性保持部材によって基板上に保持された圧電振動子に関する。
　圧電振動子の一態様として、基板の主面に圧電振動素子が片持ち支持により載置される構造が知られている。このような構造においては、例えば、圧電振動素子に形成された電極と基板に形成された電極の電気的導通を図るとともに、圧電振動素子を機械的に保持する接着剤が用いられる。例えば、特許文献１には、圧電振動片を保持する接着剤に良導体の金属が被覆された球状スペーサが混入された、圧電デバイスが開示されている。
特開２０１４－１５０４５２号公報
　圧電振動素子は、圧電基板と、圧電基板の両主面に設けられた励振電極とを備える。一般的に、圧電振動素子は、励振電極で挟まれた励振部分から圧電基板の外縁に近づくにつれて振動が減衰していく。ここで、圧電振動子が小型化した場合は、圧電振動素子と基板主面との接着において、圧電振動素子の外縁付近（すなわち、振動が減衰している領域）のみならず、圧電振動素子の励振部分に近い部分（すなわち、振動が充分に減衰していない領域）にも接着剤を付すこととなる。この点、特許文献１に開示されるような圧電デバイスでは、当該圧電振動素子の励振部分に近い部分に接合された接着剤により振動が阻害され、圧電振動子の特性が劣化するという問題がある。
　本発明はこのような事情に鑑みてなされたものであり、圧電振動子が小型化した場合においても振動子特性の劣化が抑制される圧電振動子を提供することを目的とする。
　本発明の一側面に係る圧電振動子は、圧電振動素子と、対向する第１及び第２主面を有する基板と、圧電振動素子を基板の第１主面上に励振可能に保持する導電性保持部材と、を備え、導電性保持部材は、導電性材料を主成分とする第１フィラーと、絶縁性材料を主成分とするとともに第１フィラーよりもヤング率の値が小さい第２フィラーと、を含み、基板の第１主面の法線方向から見た平面視において、導電性保持部材の中央領域よりも、導電性保持部材の外周領域において第２フィラーが密状態に配置される。
　上記構成によれば、導電性保持部材のうち、中央領域に比べて外周領域のヤング率の値が小さくなる。従って、圧電振動素子の励振部分に近い部分（すなわち、振動が充分に減衰していない領域）に、導電性保持部材における外周領域（すなわち、比較的柔らかい領域）が接合されることとなる。従って、導電性保持部材の接合による振動への影響が減少し、圧電振動子の振動子特性の劣化が抑制される。
　本発明の一側面に係る圧電振動子は、圧電振動素子と、対向する第１及び第２主面を有する基板と、圧電振動素子を基板の第１主面上に励振可能に保持する導電性保持部材と、を備え、導電性保持部材は、導電性材料を主成分とする第１フィラーと、絶縁性材料を主成分とするとともに当該第１フィラーよりもヤング率の値が小さい第２フィラーと、を含み、基板の第１主面の法線方向から見た平面視において、導電性保持部材の中央領域における第１フィラーの容積の第２フィラーの容積に対する比率Ｈ１が、導電性保持部材の外周領域における第１フィラーの容積の第２フィラーの容積に対する比率Ｈ２より高い。
　上記構成によれば、導電性保持部材のうち、中央領域に比べて外周領域のヤング率の値が小さくなる。従って、圧電振動素子の励振部分に近い部分（すなわち、振動が充分に減衰していない領域）に、導電性保持部材における外周領域（すなわち、比較的柔らかい領域）が接合されることとなる。従って、導電性保持部材の接合による振動への影響が減少し、圧電振動子の振動子特性の劣化が抑制される。
　本発明によれば、圧電振動子が小型化した場合においても振動子特性の劣化が抑制される圧電振動子を提供することができる。
図１は、本発明の一実施形態に係る圧電振動子の分解斜視図である。 図２は、図１のＩＩ－ＩＩ線断面図である。 図３は、導電性保持部材の上面図を模式的に示した図である。 図４は、導電性保持部材の顕微鏡写真である。 図５は、本発明の一実施形態に係る圧電振動子の平面図である。
　以下に本発明の実施形態を説明する。以下の図面の記載において、同一又は類似の構成要素は同一又は類似の符号で表している。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。
　図１及び図２を参照しつつ、本発明の一実施形態に係る圧電振動子１を説明する。図１は、本発明の一実施形態に係る圧電振動子の分解斜視図であり、図２は、図１のＩＩ－ＩＩ線断面図である。
　図１に示されるように、本実施形態に係る圧電振動子１は、圧電振動素子１００（Ｐｉｅｚｏｅｌｅｃｔｒｉｃ　Ｒｅｓｏｎａｔｏｒ）と、蓋部材２００と、基板３００と、を備える。蓋部材２００及び基板３００は、圧電振動素子１００を収容するための保持器（ケース又はパッケージ）の構成の一部である。
　圧電振動素子１００は、圧電基板１１０と、圧電基板１１０の表裏面にそれぞれ設けられた励振電極（Ｅｘｃｉｔａｔｉｏｎ　Ｅｌｅｃｔｒｏｄｅｓ）１２０，１３０（以下では、「第１励振電極１２０」及び「第２励振電極１３０」ともいう。）と、を含む。
　圧電基板１１０は、所定の圧電材料から形成され、その材料は特に限定されるものではない。図１に示される例では、圧電基板１１０は、所定の結晶方位を有する水晶材料から形成されている。圧電基板１１０は、例えば、ＡＴカットされた水晶片（Ｑｕａｒｔｚ　Ｃｒｙｓｔａｌ　Ｅｌｅｍｅｎｔ）である。ＡＴカットされた水晶片は、人工水晶の結晶軸であるＸ軸、Ｙ軸、Ｚ軸のうち、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秒分回転させた軸をそれぞれＹ´軸及びＺ´軸とした場合、Ｘ軸及びＺ´軸によって特定される面（以下、「ＸＺ´面」と呼ぶ。他の軸によって特定される面についても同様である。）と平行な面を主面として切り出されたものである。図１に示される例では、ＡＴカットされた水晶片である圧電基板１１０は、Ｘ軸に沿って延びる長辺と、Ｚ´軸に沿って延びる短辺と、Ｙ´軸に沿って延びる厚み方向の辺と、を有しており、ＸＺ´面において略矩形状をなしている。ＡＴカットされた水晶片を用いた圧電振動素子は、広い温度範囲で高い周波数安定性を有し、また、経時変化特性にも優れている。また、ＡＴカットされた水晶片を用いた圧電振動素子（すなわち、水晶振動素子（Ｑｕａｒｔｚ　Ｃｒｙｓｔａｌ　Ｒｅｓｏｎａｔｏｒ））は、主要振動として厚みすべり振動モード（Ｔｈｉｃｋｎｅｓｓ　Ｓｈｅａｒ　Ｍｏｄｅ）を含む。以下、ＡＴカットの軸方向を基準として圧電振動子１の各構成を説明する。
　なお、圧電基板は上記構成に限定されるものではなく、例えば、Ｚ´軸に沿って延びる長辺と、Ｘ軸に沿って延びる短辺とを有する矩形状のＡＴカットされた水晶片を適用してもよい。あるいは、主要振動が厚みすべり振動モードを含んでいれば、例えば、ＢＴカットなどのＡＴカット以外のカットの水晶片であってもよい。また、圧電基板の材料は水晶に限定されるものではなく、例えば、ＰＺＴなどの圧電セラミックや酸化亜鉛などのその他の圧電材料を用いてもよい。また、圧電振動素子は、例えばＭＥＭＳ（Ｍｉｃｒｏ　Ｅｌｅｃｔｒｏ　Ｍｅｃｈａｎｉｃａｌ　Ｓｙｓｔｅｍｓ）であってもよく、具体的には、シリコーン基板にＭＥＭＳを形成したＳｉ－ＭＥＭＳを用いてもよい。さらに、圧電振動素子は、ＡｌＮ、ＬｉＴａＯ３、ＬｉＮｂＯ３、ＰＺＴなどの所定の圧電材料を用いた圧電ＭＥＭＳであってもよい。
　第１励振電極１２０は、圧電基板１１０の第１主面１１２に形成され、第２励振電極１３０は、圧電基板１１０の第２主面１１４に形成されている。第１励振電極１２０及び第２励振電極１３０は、一対の電極であり、ＸＺ´面を平面視した場合に略全体が重なり合うように配置されている。圧電基板１１０は、第１励振電極１２０及び第２励振電極１３０によって挟まれた励振部分を有する。
　圧電基板１１０には、第１励振電極１２０に引出電極１２２を介して電気的に接続された接続電極１２４と、第２励振電極１３０に引出電極１３２を介して電気的に接続された接続電極１３４と、が形成される。具体的には、引出電極１２２は、第１主面１１２において第１励振電極１２０からＸ軸負方向側短辺に向かって引き出され、さらに圧電基板１１０のＺ´軸正方向側の側面を通って、第２主面１１４に形成された接続電極１２４に接続される。他方、引出電極１３２は、第２主面１１４において第２励振電極１３０からＸ軸負方向側短辺に向かって引き出され、第２主面１１４に形成された接続電極１３４に接続される。接続電極１２４，１３４はＸ軸負方向側短辺に沿って配置され、後述する導電性保持部材３４０，３４２を介して基板３００に電気的導通を図るとともに機械的に保持される。なお、接続電極１２４，１３４及び引出電極１２２，１３２の配置やパターン形状は限定されるものではなく、他の部材との電気的接続を考慮して適宜変更されてもよい。
　第１励振電極１２０及び第２励振電極１３０を含む上記各電極は、例えば、圧電基板１１０の表面に接合力を高めるためクロム（Ｃｒ）層が下地として形成されており、クロム層の表面に金（Ａｕ）層が形成されている。なお、その材料は限定されるものではない。
　図２に示されるように、蓋部材２００は、基板３００の第１主面３０２に対向して開口した凹部を有している。蓋部材２００は、開口の全周に亘って、凹部の底面から立ち上がるように形成された側壁部２０２が設けられており、側壁部２０２は、基板３００の第１主面３０２に対向する端面２０４を有している。端面２０４は、接合材２５０を介して基板３００の第１主面３０２と接合される。なお、蓋部材２００は基板３００に接合されたときに圧電振動素子１００を内部空間に収容することができる形状であればよく、その形状は特に限定されるものではない。蓋部材２００の材質は特に限定されるものではないが、例えば金属などの導電性材料で構成されていてもよい。これによれば、蓋部材２００を接地電位に電気的に接続させることによりシールド機能を付加することができる。蓋部材２００が金属によって形成される場合、例えば、鉄（Ｆｅ）及びニッケル（Ｎｉ）を含む合金（例えば４２アロイ）で形成されてもよい。あるいは、蓋部材２００の表面にさらに金（Ａｕ）層などの表面層が形成されてもよい。表面に金層が形成されることにより、蓋部材２００の酸化防止を図ることができる。あるいは、蓋部材２００は、絶縁性材料又は導電性材料及び絶縁性材料の複合構造であってもよい。
　図１に戻り、基板３００は、圧電振動素子１００を励振可能に保持するものである。図１に示される例では、圧電振動素子１００が、導電性保持部材３４０，３４２を介して基板３００の第１主面３０２上に励振可能に保持されている。
　基板３００は、Ｘ軸に沿って延びる長辺と、Ｚ´軸に沿って延びる短辺と、Ｙ´軸に沿って延びる厚み方向の辺と、を有しており、ＸＺ´面において略矩形状をなしている。基板３００は、例えば単層の絶縁性セラミックで形成されている。別の実施形態として、基板３００は、複数の絶縁性セラミックシートを積層して焼成することによって形成されてもよい。基板３００は耐熱性材料から構成されることが好ましい。なお、基板３００は、図１に示されるように平板状をなしていてもよく、又は蓋部材２００に対向する向きに開口した凹状をなしていてもよい。
　基板３００には、第１主面３０２に接続電極３２０，３２２、コーナー電極３２４，３２６、及び引出電極３２０ａ，３２２ａが形成され、側面に側面電極３３０，３３２，３３４，３３６が形成され、第２主面３０４に外部電極３６０，３６２，３６４，３６６が形成されている。
　接続電極３２０，３２２は、基板３００の第１主面３０２上において、Ｘ軸負方向側の短辺に沿ってかつ当該短辺から間隔を空けて形成されている。接続電極３２０は導電性保持部材３４０を介して圧電振動素子１００の接続電極１２４と接続され、接続電極３２２は、導電性保持部材３４２を介して圧電振動素子１００の接続電極１３４と接続される。接続電極３２０，３２２の材料は特に限定されないが、例えば、モリブデン（Ｍｏ）、ニッケル（Ｎｉ）、及び金（Ａｕ）の積層により構成される。なお、導電性保持部材３４０，３４２の構成の詳細については後述する。
　引出電極３２０ａは、接続電極３２０から基板３００の１つの角部に設けられた側面電極３３０に向かって引き出されている。引出電極３２２ａは、接続電極３２２から基板３００における側面電極３３０の対角位置にある角部に設けられた側面電極３３２に向かって、Ｘ軸方向に沿って引き出されている。
　本実施形態においては、残りの角部（接続電極３２０，３２２と電気的に接続された引出電極３２０ａ，３２２ａが配置された角部以外の角部）にコーナー電極３２４，３２６が形成されている。コーナー電極３２４，３２６は、第１励振電極１２０及び第２励振電極１３０のいずれとも電気的に接続されていない電極である。
　複数の側面電極３３０，３３２，３３４，３３６は、それぞれ、基板３００の各角部付近の側面に形成されている。また、複数の外部電極３６０，３６２，３６４，３６６は、それぞれ、基板３００の第２主面３０４上の各角部付近に形成されている。具体的には、側面電極３３０及び外部電極３６０はＸ軸負方向及びＺ´軸正方向側の角部に配置され、側面電極３３２及び外部電極３６２はＸ軸正方向及びＺ´軸負方向側の角部に配置され、側面電極３３４及び外部電極３６４はＸ軸正方向及びＺ´軸正方向側の角部に配置され、側面電極３３６及び外部電極３６６はＸ軸負方向及びＺ´軸負方向側の角部に配置されている。
　側面電極３３０，３３２，３３４，３３６は、第１主面３０２と第２主面３０４の各電極を電気的に接続するために設けられている。図１に示される例では、基板３００の角部は、その一部が円筒曲面状（キャスタレーション形状とも呼ばれる。）に切断して形成された切り欠き側面をなしており、このような切り欠き側面に側面電極３３０，３３２，３３４，３３６が形成されている。なお、基板３００の角部の形状はこれに限定されるものではなく、切り欠きの形状は平面状であってもよく、又は切り欠きがなく、平面視して四隅が直角である矩形状であってもよい。
　外部電極３６０，３６２，３６４，３６６は、実装基板（図示しない）と電気的に接続するための電極である。外部電極３６０，３６２，３６４，３６６は、各々、対応する角部の側面に形成された側面電極３３０，３３２，３３４，３３６に電気的に接続される。これにより、外部電極３６０，３６２，３６４，３６６は、側面電極３３０，３３２，３３４，３３６を介して基板３００の第１主面３０２側の電極に電気的に導通可能となる。
　具体的には、複数の外部電極のうち、外部電極３６０は、側面電極３３０、引出電極３２０ａ、接続電極３２０、及び導電性保持部材３４０を介して第１励振電極１２０に電気的に接続され、外部電極３６２は、側面電極３３２、引出電極３２２ａ、接続電極３２２、及び導電性保持部材３４２を介して第２励振電極１３０に電気的に接続される。すなわち、外部電極３６０，３６２は、第１励振電極１２０又は第２励振電極１３０と電気的に接続される入出力端子である。
　また、残りの外部電極３６４，３６６は、圧電振動素子１００の第１励振電極１２０又は第２励振電極１３０とは電気的に接続されることがないダミー電極である。外部電極３６４，３６６を形成することにより、全ての角部に外部電極を形成することができるため、圧電振動子１を他の部材に電気的に接続する処理工程が容易となる。なお、外部電極３６４，３６６は、接地電位が供給される接地用電極としての機能を有していてもよい。例えば、蓋部材２００が導電性材料からなる場合、蓋部材２００を接地用電極である外部電極３６４，３６６に電気的に接続することにより、蓋部材２００にシールド機能を付与することができる。
　なお、基板３００に形成される接続電極、コーナー電極、引出電極、側面電極、及び外部電極の各構成は上述の例に限定されるものではなく、様々に変形して適用することができる。例えば、外部電極の個数は４つに限るものではなく、例えば対角上に配置された２つの入出力端子のみであってもよい。また、側面電極は角部に配置されたものに限らず、角部を除く基板３００のいずれかの側面に形成されてもよい。この場合、既に説明したとおり、側面の一部を円筒曲面状に切断した切り欠き側面を形成し、角部を除く当該側面に側面電極を形成してもよい。さらに、コーナー電極３２４，３２６、側面電極３３４，３３６、及び外部電極３６４，３６６は形成しなくてもよい。また、基板３００に第１主面３０２から第２主面３０４へ貫通するスルーホールを形成し、このスルーホールによって第１主面３０２に形成した接続電極から第２主面３０４へ電気的導通を図ってもよい。
　接合材２５０は、蓋部材２００及び基板３００のそれぞれの全周に亘って設けられ、蓋部材２００の側壁部２０２の端面２０４と基板３００の第１主面３０２とを接合する。接合材２５０の材料は限定されるものではないが、例えば金（Ａｕ）‐錫（Ｓｎ）共晶合金としてもよい。蓋部材と基板の接合を金属接合とすることにより、蓋部材が導電性材料で構成されている場合、蓋部材と基板との間の電気的導通を図ることができる。また、封止性を向上させることができる。
　蓋部材２００及び基板３００の両者が接合材２５０を介して接合されることによって、圧電振動素子１００が、蓋部材２００の凹部と基板３００とによって囲まれた内部空間（キャビティ）に密封封止される。この場合、内部空間の圧力は大気圧力よりも低圧な真空状態であることが好ましく、これにより第１励振電極１２０及び第２励振電極１３０の酸化による経時変化などが低減される。
　上述の構成により、圧電振動子１においては、基板３００の外部電極３６０，３６２を介して、圧電振動素子１００における一対の第１励振電極１２０及び第２励振電極１３０の間に交番電界が印加される。これにより、厚みすべり振動モードを含む振動モードによって圧電基板１１０が振動し、該振動に伴う共振特性が得られる。
　次に、図２～図４を参照しつつ、導電性保持部材３４２を例として、導電性保持部材の構成の詳細について説明する。なお、導電性保持部材３４０については、導電性保持部材３４２と同様であるため詳細な説明は省略する。図３は、導電性保持部材の上面図を模式的に示した図であり、図４は、導電性保持部材の顕微鏡写真である。具体的には、図３は、接続電極３２２上に設けられた導電性保持部材３４２を、基板３００の第１主面３０２の法線方向（Ｙ´軸方向）から平面視（すなわち、ＸＺ´面の平面視）した上面図を模式的に示している。なお、図３において接続電極３２２は説明の都合上、矩形状に示されているが、接続電極の形状はこれに限られない。
　導電性保持部材３４２は、例えば、接着剤が熱硬化されて形成されたものである。導電性保持部材３４２は、圧電振動素子１００を励振可能に保持するとともに、圧電振動素子１００に形成された接続電極１３４と基板３００に形成された接続電極３２２とを電気的に導通する。図３に示されるように、導電性保持部材３４２は、例えば、ＸＺ´面の平面視において円形状である。例えば、円形状は、円状又は楕円状を含む。あるいは、導電性保持部材３４２は、ＸＺ´面の平面視において矩形状などのその他の形状であってもよい。図２及び図３に示されるように、導電性保持部材３４２は、接着剤（バインダー）４００と、当該接着剤４００に混入された複数の球状スペーサ４１０（第２フィラー）及び複数の金属粒子４２０（第１フィラー）を含む。なお、接着剤４００は、例えば樹脂を主成分とする。
　複数の球状スペーサ４１０の各々は、例えば、弾力性を有するゴム、又は、シリコーン系樹脂などのプラスチック等の樹脂を主成分とする球形状である。例えば、球形状は、球体や楕円体などを含む。本実施形態においては、球状スペーサ４１０は金属により被覆されておらず、表面に樹脂材料が露出している。このような球状スペーサは、金属により被覆された球状スペーサに比べてヤング率の値が小さく、音響インピーダンスが低い。また、球状スペーサ４１０は、金属粒子４２０よりもヤング率の値が小さく、音響インピーダンスが低い。
　複数の金属粒子４２０の各々は、複数の金属原子が結合してなる粒子である。複数の金属粒子４２０の材料は特に限定されないが、例えば、銀（Ａｇ）等である。複数の金属粒子４２０が接着剤４００の内部において互いに接触しつつ硬化されることにより、保持部材が導電性を備えることとなる。なお、複数の金属粒子４２０の各々が、接続電極３２２上に配置された複数の球状スペーサ４１０によって形成される隙間に入り込むように、金属粒子４２０の粒子径は、例えば、球状スペーサ４１０によって形成される隙間よりも小さい。
　図２に示される例では、複数の球状スペーサ４１０は、例えば、接続電極３２２の表面上に高さ方向（Ｙ´軸方向）に２段積まれている。これにより、圧電振動素子１００が基板３００の第１主面３０２から所定の間隔、すなわち、球状スペーサ４１０の外形寸法（例えば、６μｍ程度）の２段分に相当する間隔（例えば、１０μｍ程度）を空けて保持されることとなる。従って、圧電振動素子１００の第２主面１１４と基板３００の第１主面３０２との距離が一定に保たれ、当該両主面に形成される電極間に発生する寄生容量の大きさを一定に保つことができる。なお、積まれる球状スペーサの段数はこれに限られず、１段であってもよく、３段以上であってもよい。
　圧電振動素子１００は、一般的に、励振部分から圧電基板１１０の外縁に近づくにつれて振動が減衰していく。従って、仮に導電性保持部材が一様に硬い場合、圧電振動子の小型化に伴い、圧電振動素子の励振部分に近い部分、具体的には、振動が充分に減衰されていない領域に導電性保持部材が接合され、当該導電性保持部材により振動が阻害され得る。具体的には、例えば、振動が圧電振動素子１００から導電性保持部材を介して基板３００に漏出し得る。
　そこで、本実施形態においては、図３に示されるように、基板３００の第１主面３０２の法線方向（Ｙ´軸方向）からの平面視において、球状スペーサ４１０は、導電性保持部材３４２の中央領域Ｒｉｎよりも外周領域Ｒｏｕｔにおいて密状態に配置されている。一方、金属粒子４２０は、導電性保持部材３４２の外周領域Ｒｏｕｔよりも中央領域Ｒｉｎにおいて密状態に配置されている。また、本実施形態においては、導電性保持部材３４２の中央領域Ｒｉｎにおける、金属粒子４２０の容積の球状スペーサ４１０の容積に対する比率Ｈ１が、導電性保持部材３４２の外周領域Ｒｏｕｔにおける、金属粒子４２０の容積の球状スペーサ４１０の容積に対する比率Ｈ２より高くなっている。また、上述の通り、球状スペーサ４１０は金属粒子４２０より柔らかい。これにより、導電性保持部材３４２は、中央領域Ｒｉｎでは硬い金属粒子４２０が密状態となり、外周領域Ｒｏｕｔでは柔らかい球状スペーサ４１０が密状態となるため、中央領域Ｒｉｎに比べ外周領域Ｒｏｕｔの方が柔らかくなる。
　図４は、圧電振動素子１００が接合された導電性保持部材３４２から圧電振動素子１００をはがした後、基板３００の第１主面３０２の法線方向（Ｙ´軸方向）から見た顕微鏡写真である。なお、図４においては、球状スペーサ４１０が明確となるように、球状スペーサ４１０が白い円で示されている。また、接続電極３２２は円形状を有している。
　図４に示されるように、球状スペーサ４１０は、導電性保持部材３４２における中央領域に比べて外周領域において密状態となっていることが分かる。特に、導電性保持部材３４２の外縁においては、中央領域を取り囲むように球状スペーサ４１０が互いに隣接して配置されている。
　上述の構成により、本実施形態においては、圧電振動素子１００の励振部分に近い部分、具体的には振動が充分に減衰していない領域には導電性保持部材３４０，３４２のうち比較的柔らかい外周領域Ｒｏｕｔが接合され、圧電振動素子１００の外縁付近、具体的には振動が減衰している領域には導電性保持部材３４０，３４２のうち比較的硬い中央領域Ｒｉｎが接合されることとなる（図２参照）。これにより、導電性保持部材３４０，３４２は、ヤング率の値が一様な接着剤に比べて、接合が振動子特性に与える影響が小さくなる。
　すなわち、導電性保持部材３４０，３４２の外周領域Ｒｏｕｔは比較的柔らかく、音響インピーダンスが低い。従って、圧電振動素子１００の振動が充分に減衰していない領域においては、音響インピーダンスが比較的高い圧電振動素子１００及び基板３００に、音響インピーダンスが比較的低い導電性保持部材３４０，３４２が接合されるため、音響インピーダンスの差を大きくとることができる。これにより、一様に硬い接着剤を用いる場合に比べて、圧電振動素子１００と導電性保持部材３４０，３４２との境界面における反射波が増加し、透過波が減少するため、圧電振動素子１００から導電性保持部材３４０，３４２を介して基板３００に漏出する振動が減少する。従って、導電性保持部材の接合に起因する振動の阻害が軽減され、振動エネルギーの損失成分に相当する等価直列抵抗（ＥＳＲ：Ｅｑｕｉｖａｌｅｎｔ　Ｓｅｒｉｅｓ　Ｒｅｓｉｓｔａｎｃｅ）を低下させることができる。よって圧電振動子の特性の劣化が抑制される。
　また、導電性保持部材３４０，３４２を圧電振動素子１００の励振部分に近い部分にも接合することが可能となるため、導電性保持部材３４０，３４２と圧電振動素子１００との接合面積が増大する。従って、圧電振動子が小型化しても、圧電振動子の特性の劣化を抑制しつつ、接合強度を向上させることができる。
　また、導電性保持部材３４０，３４２の中央領域Ｒｉｎにおける、金属粒子４２０の容積の球状スペーサ４１０の容積に対する比率Ｈ１が、導電性保持部材３４０，３４２の外周領域Ｒｏｕｔにおける、金属粒子４２０の容積の球状スペーサ４１０の容積に対する比率Ｈ２より高い。また、金属粒子４２０は導電性材料を主成分とし、球状スペーサ４１０は絶縁性材料を主成分とする。従って、当該中央領域Ｒｉｎの単位面積当たりの導電性が向上し、導電性保持部材３４０，３４２の導電性の信頼性が向上する。
　また、本実施形態においては、球状スペーサを金属により被覆する必要がないため、球状スペーサが金属により被覆される構成に比べて製造コストが安価となる。
　なお、図１に示される例では、圧電振動素子１００は、その一方端が導電性保持部材３４０，３４２により固定されており、その他方端が自由となっているが、圧電振動素子１００はその両端において基板３００に固定されていてもよい。すなわち、接続電極３２０，３２２の一方がＸ軸正方向側に形成され、他方がＸ軸負方向側に形成されるなど、基板３００の第１主面３０２上において互いに異なる側に配置されていてもよい。
　また、球状スペーサ４１０及び金属粒子４２０の配置については、上述の構成に限られない。例えば、金属粒子が導電性保持部材内に一様に配置され、球状スペーサが導電性保持部材の外周領域において中央領域より密に配置されていてもよい。
　図５は、本発明の一実施形態に係る圧電振動子の平面図である。図５は、図１に示される圧電振動子１における蓋部材２００及び接合材２５０を省略した図である。
　図５に示されるように、本実施形態においては、基板３００の第１主面３０２の法線方向（Ｙ´軸方向）からの平面視において、導電性保持部材３４０，３４２の外周領域Ｒｏｕｔの一部が、圧電振動素子１００の外縁よりも外側に配置されている。これにより、導電性保持部材３４０，３４２においてヤング率の値が比較的大きい中央領域Ｒｉｎが、圧電振動素子１００の外縁付近と接合されることとなる。ここで、当該圧電振動素子１００の外縁付近は、振動が充分に減衰しているため、導電性保持部材３４０，３４２の接合による圧電振動素子１００の振動への影響が少ない。従って、圧電振動子の振動子特性の劣化が抑制される。
　以上、本発明の例示的な実施形態について説明した。圧電振動子１において、導電性保持部材３４０，３４２は、複数の金属粒子４２０と、当該複数の金属粒子よりヤング率の値が小さい複数の球状スペーサ４１０と、を含み、ＸＺ´面の平面視において、導電性保持部材３４０，３４２の中央領域Ｒｉｎよりも外周領域Ｒｏｕｔにおいて球状スペーサ４１０が密状態に配置される。これにより、圧電振動素子１００の励振部分に近い部分（すなわち、振動が充分に減衰していない領域）には導電性保持部材３４０，３４２のうち中央領域Ｒｉｎに比べて柔らかい外周領域Ｒｏｕｔが接合されることとなる。従って、圧電振動素子１００から導電性保持部材３４０，３４２を介して基板３００に漏出する振動が減少し、圧電振動子１の振動子特性の劣化が抑制される。また、導電性保持部材３４０，３４２と圧電振動素子１００との接合面積が増大するため、接合強度が向上する。
　また、圧電振動子１は、導電性保持部材３４０，３４２のＸＺ´面の平面視において、導電性保持部材３４０，３４２の外周領域Ｒｏｕｔよりも中央領域Ｒｉｎにおいて金属粒子４２０が密状態に配置される。これにより、導電性保持部材３４０，３４２の中央領域Ｒｉｎの単位面積当たりの導電性が向上し、導電性の信頼性が向上する。
　また、圧電振動子１において、導電性保持部材３４０，３４２の中央領域Ｒｉｎにおける、金属粒子４２０の容積の球状スペーサ４１０の容積に対する比率Ｈ１が、外周領域Ｒｏｕｔにおける、金属粒子４２０の容積の球状スペーサ４１０の容積に対する比率Ｈ２より高い。これにより、圧電振動素子１００の励振部分に近い部分（すなわち、振動が充分に減衰していない領域）には導電性保持部材３４０，３４２のうち中央領域Ｒｉｎに比べて柔らかい外周領域Ｒｏｕｔが接合されることとなる。従って、圧電振動素子１００から導電性保持部材３４０，３４２を介して基板３００に漏出する振動が減少し、圧電振動子１の振動子特性の劣化が抑制される。また、導電性保持部材３４０，３４２と圧電振動素子１００との接合面積が増大するため、接合強度が向上する。また、導電性保持部材３４０，３４２の中央領域Ｒｉｎの単位面積当たりの導電性が向上し、導電性の信頼性が向上する。
　また、圧電振動子１においては、ＸＺ´面の平面視において、導電性保持部材３４０，３４２の外周領域Ｒｏｕｔの一部が、圧電振動素子１００の外縁よりも外側に配置されている。これにより、導電性保持部材３４０，３４２においてヤング率の値が比較的大きい中央領域Ｒｉｎが、振動が充分に減衰している圧電振動素子１００の外縁付近と接合されることとなる。従って、導電性保持部材３４０，３４２の接合による圧電振動素子１００の振動への影響が少なく、圧電振動子１の振動子特性の劣化が抑制される。
　また、圧電振動子１においては、球状スペーサ４１０の混入により、圧電振動素子１００が基板３００の第１主面３０２から所定の間隔を空けて保持されることとなる。従って、圧電振動素子１００の第２主面１１４と基板３００の第１主面３０２に形成される電極間に発生する寄生容量の大きさを一定に保つことができる。
　また、金属粒子４２０の材料は特に限定されないが、例えば銀を主成分としてもよい。
　また、球状スペーサ４１０の材料は特に限定されないが、例えばシリコーン系樹脂を主成分としてもよい。
　なお、以上説明した各実施形態は、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／改良され得るととともに、本発明にはその等価物も含まれる。すなわち、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およびその配置、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。
　１　圧電振動子
　１００　圧電振動素子
　１１０　圧電基板
　１２０，１３０　励振電極
　１２２，１３２　引出電極
　１２４，１３４　接続電極
　２００　蓋部材
　２５０　接合材
　３００　基板
　３２０，３２２　接続電極
　３２０ａ，３２２ａ　引出電極
　３２４，３２６　コーナー電極
　３３０，３３２，３３４，３３６　側面電極
　３４０，３４２　導電性保持部材
　３６０，３６２，３６４，３６６　外部電極
　４００　接着剤
　４１０　球状スペーサ
　４２０　金属粒子
　Ｒｉｎ　中央領域
　Ｒｏｕｔ　外周領域

Claims (8)

  1. 　圧電振動素子と、
    　対向する第１及び第２主面を有する基板と、
    　前記圧電振動素子を前記基板の前記第１主面上に励振可能に保持する導電性保持部材と、
    を備え、
    　前記導電性保持部材は、導電性材料を主成分とする第１フィラーと、絶縁性材料を主成分とするとともに前記第１フィラーよりもヤング率の値が小さい第２フィラーと、を含み、
    　前記基板の前記第１主面の法線方向から見た平面視において、前記導電性保持部材の中央領域よりも、前記導電性保持部材の外周領域において前記第２フィラーが密状態に配置された、圧電振動子。
  2. 　前記基板の前記第１主面の法線方向から見た平面視において、前記導電性保持部材の外周領域よりも、前記導電性保持部材の中央領域において前記第１フィラーが密状態に配置された、請求項１記載の圧電振動子。
  3. 　圧電振動素子と、
    　対向する第１及び第２主面を有する基板と、
    　前記圧電振動素子を前記基板の前記第１主面上に励振可能に保持する導電性保持部材と、
    を備え、
    　前記導電性保持部材は、導電性材料を主成分とする第１フィラーと、絶縁性材料を主成分とするとともに前記第１フィラーよりもヤング率の値が小さい第２フィラーと、を含み、
    　前記基板の前記第１主面の法線方向から見た平面視において、前記導電性保持部材の中央領域における前記第１フィラーの容積の前記第２フィラーの容積に対する比率Ｈ１が、前記導電性保持部材の外周領域における前記第１フィラーの容積の前記第２フィラーの容積に対する比率Ｈ２より高い、圧電振動子。
  4. 　前記基板の前記第１主面の法線方向から見た平面視において、前記外周領域の一部が、前記圧電振動素子の外縁よりも外側に配置された、請求項１から３のいずれか一項に記載の圧電振動子。
  5. 　前記第２フィラーは、前記圧電振動素子を前記基板の前記第１主面から所定の間隔を空けて保持する球状スペーサである、請求項１から４のいずれか一項に記載の圧電振動子。
  6. 　前記第１フィラーは銀を主成分とする、請求項１から５のいずれか一項に記載の圧電振動子。
  7. 　前記第２フィラーはシリコーン系樹脂を主成分とする、請求項１から６のいずれか一項に記載の圧電振動子。
  8. 　前記基板に接合され、前記基板とで形成される内部空間に前記圧電振動素子を収容する蓋部材をさらに備える、請求項１から７のいずれか一項に記載の圧電振動子。
PCT/JP2017/028960 2016-08-31 2017-08-09 圧電振動子 WO2018043084A1 (ja)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2018537091A JP6956093B2 (ja) 2016-08-31 2017-08-09 圧電振動子
CN201780052755.8A CN109690941B (zh) 2016-08-31 2017-08-09 压电振子
US16/283,011 US11233497B2 (en) 2016-08-31 2019-02-22 Piezoelectric vibrator

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2016-169722 2016-08-31
JP2016169722 2016-08-31

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US16/283,011 Continuation US11233497B2 (en) 2016-08-31 2019-02-22 Piezoelectric vibrator

Publications (1)

Publication Number Publication Date
WO2018043084A1 true WO2018043084A1 (ja) 2018-03-08

Family

ID=61301548

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2017/028960 WO2018043084A1 (ja) 2016-08-31 2017-08-09 圧電振動子

Country Status (4)

Country Link
US (1) US11233497B2 (ja)
JP (1) JP6956093B2 (ja)
CN (1) CN109690941B (ja)
WO (1) WO2018043084A1 (ja)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019033379A (ja) * 2017-08-08 2019-02-28 日本電波工業株式会社 水晶デバイス

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009152717A (ja) * 2007-12-19 2009-07-09 Epson Toyocom Corp 圧電素子
WO2011125414A1 (ja) * 2010-04-01 2011-10-13 株式会社村田製作所 電子部品及びその製造方法

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002280716A (ja) * 2001-03-19 2002-09-27 Pioneer Electronic Corp 電子部品の取付方法及び接着体
JP5943187B2 (ja) * 2012-03-21 2016-06-29 セイコーエプソン株式会社 振動素子、振動子、電子デバイス、および電子機器
JP2014150452A (ja) 2013-02-01 2014-08-21 Asahi Kasei Electronics Co Ltd 圧電デバイス
WO2015178178A1 (ja) * 2014-05-17 2015-11-26 京セラ株式会社 圧電部品
CN108432126A (zh) * 2015-12-24 2018-08-21 株式会社村田制作所 压电振荡装置及其制造方法
JP6772574B2 (ja) * 2016-06-16 2020-10-21 株式会社村田製作所 圧電振動子及びその製造方法
WO2018043340A1 (ja) * 2016-08-31 2018-03-08 株式会社村田製作所 圧電振動子
WO2019167920A1 (ja) * 2018-02-28 2019-09-06 株式会社村田製作所 振動基板、振動素子、及び振動子

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009152717A (ja) * 2007-12-19 2009-07-09 Epson Toyocom Corp 圧電素子
WO2011125414A1 (ja) * 2010-04-01 2011-10-13 株式会社村田製作所 電子部品及びその製造方法

Also Published As

Publication number Publication date
CN109690941A (zh) 2019-04-26
CN109690941B (zh) 2023-02-28
US20190190485A1 (en) 2019-06-20
JPWO2018043084A1 (ja) 2019-03-28
US11233497B2 (en) 2022-01-25
JP6956093B2 (ja) 2021-10-27

Similar Documents

Publication Publication Date Title
JP2001238291A (ja) 圧電音響部品およびその製造方法
US10476475B2 (en) Piezoelectric resonator unit and manufacturing method for the same
JP6663599B2 (ja) 圧電振動子及び圧電振動子の製造方法
JP6315418B1 (ja) 圧電振動素子搭載用の集合基板及びその製造方法、並びに、圧電振動子の製造方法
WO2019167920A1 (ja) 振動基板、振動素子、及び振動子
WO2018043084A1 (ja) 圧電振動子
WO2018043340A1 (ja) 圧電振動子
JP6739759B2 (ja) 圧電振動子
JP6540955B2 (ja) 電子部品及びその製造方法
WO2021131121A1 (ja) 圧電振動素子、圧電振動子及び電子装置
CN109804560B (zh) 压电振子及其制造方法
WO2021220542A1 (ja) 圧電振動子
JP7465458B2 (ja) 圧電振動子
JP2018117243A (ja) 圧電振動子及びその製造方法
WO2021215040A1 (ja) 圧電振動子
CN113302838B (zh) 振动元件、振子以及振动元件的制造方法
WO2021210214A1 (ja) 圧電振動子及びその製造方法
WO2022130668A1 (ja) 圧電振動子
WO2021186790A1 (ja) 水晶振動素子、水晶振動子及び水晶発振器
WO2022004070A1 (ja) 圧電振動子
WO2020067157A1 (ja) 水晶振動素子および水晶振動子
JP2017112544A (ja) 圧電振動子
JP4833716B2 (ja) 圧電発振器
JP2020150554A (ja) 圧電振動子及びその製造方法
JP2020167584A (ja) 振動素子、振動子及び振動素子の製造方法

Legal Events

Date Code Title Description
ENP Entry into the national phase

Ref document number: 2018537091

Country of ref document: JP

Kind code of ref document: A

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17846093

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 17846093

Country of ref document: EP

Kind code of ref document: A1