WO2020129296A1 - Piezoelectric transducer - Google Patents

Piezoelectric transducer Download PDF

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Publication number
WO2020129296A1
WO2020129296A1 PCT/JP2019/032101 JP2019032101W WO2020129296A1 WO 2020129296 A1 WO2020129296 A1 WO 2020129296A1 JP 2019032101 W JP2019032101 W JP 2019032101W WO 2020129296 A1 WO2020129296 A1 WO 2020129296A1
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WO
WIPO (PCT)
Prior art keywords
plate
piezoelectric transducer
membrane
connection
peripheral side
Prior art date
Application number
PCT/JP2019/032101
Other languages
French (fr)
Japanese (ja)
Inventor
青司 梅澤
伸介 池内
文弥 黒川
洋一 持田
永純 安達
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 CN201980079191.6A priority Critical patent/CN113261308B/en
Priority to DE112019006369.3T priority patent/DE112019006369T5/en
Publication of WO2020129296A1 publication Critical patent/WO2020129296A1/en

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
    • H10N30/204—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators using bending displacement, e.g. unimorph, bimorph or multimorph cantilever or membrane benders
    • H10N30/2047—Membrane type
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors
    • H10N30/302—Sensors
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/07—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base
    • H10N30/074—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing
    • H10N30/076—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing by vapour phase deposition

Definitions

  • the present invention relates to a piezoelectric transducer.
  • Patent Document 1 describes a capacitive ultrasonic transducer.
  • the capacitive ultrasonic transducer is formed by integrating transducer elements composed of transducer cells.
  • the oscillator cell includes a silicon substrate, a first electrode, a second electrode, a membrane, and a membrane supporting portion.
  • the first electrode is provided on the upper surface of the silicon substrate.
  • the second electrode faces the first electrode and is arranged with a predetermined gap.
  • the membrane supports the second electrode.
  • the membrane supporting portion supports the membrane.
  • the end portion of the membrane has a structure that makes it relatively easier to deform than the center portion of the membrane.
  • the structure is at least one row of grooves provided at the end of the membrane.
  • the membrane has a substantially circular shape, and the groove is a groove array provided in a substantially concentric shape in the vicinity of the peripheral edge of the membrane.
  • a plurality of grooves are formed in a substantially arc shape.
  • the membrane part has each of a piezoelectric layer, an upper electrode layer and a lower electrode layer. When these layers are formed, residual stress may occur in the membrane part.
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide a piezoelectric transducer capable of suppressing a decrease in input/output characteristics due to the influence of residual stress.
  • the piezoelectric transducer includes a base portion and a membrane portion.
  • the membrane part is indirectly supported by the base part and is located above the base part.
  • the membrane part does not overlap the base part.
  • the membrane part includes a plate-shaped part, a base end part, and a connection part.
  • the plate-shaped portion has an outer peripheral side surface when viewed from above and below.
  • the base end portion is located on the outer peripheral side of the plate-shaped portion and has an annular outer shape concentric with the plate-shaped portion when viewed in the vertical direction.
  • the connecting portion connects the plate-shaped portion and the base end portion to each other.
  • the plate-shaped portion has a piezoelectric layer, an upper electrode layer, and a lower electrode layer.
  • the upper electrode layer is arranged above the piezoelectric layer.
  • the lower electrode layer is arranged so as to face at least a part of the upper electrode layer with the piezoelectric layer interposed therebetween.
  • the plate-shaped portion has a plurality of first connection regions connected to the connection portion over the entire thickness in the vertical direction.
  • the plurality of first connection regions are located at intervals along the circumferential direction of the outer peripheral side surface of the plate-shaped portion.
  • the base end portion has a plurality of second connection regions connected to the connection portion over the entire thickness in the vertical direction.
  • the plurality of second connection regions are located at intervals in the circumferential direction.
  • the connecting portion extends from the arbitrary first connecting area of the plurality of first connecting areas to the outer peripheral side of the plate-shaped portion and passes through the arbitrary second connecting area of the plurality of second connecting areas.
  • Each of the plurality of virtual straight lines has a shape that is discontinuous due to at least one groove portion provided in the membrane portion.
  • the present invention it is possible to suppress the deterioration of the input/output characteristics due to the influence of the residual stress in the piezoelectric transducer.
  • FIG. 3 is a plan view showing the configuration of the piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 2 is a cross-sectional view of the piezoelectric transducer shown in FIG. 1 as seen from the direction of arrows II-II.
  • FIG. 5 is a cross-sectional view showing a state in which a lower electrode layer is provided on the upper surface of the active layer in the method for manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 3 is a cross-sectional view showing a state in which a piezoelectric layer is provided on the upper surface of a lower electrode layer in the method for manufacturing a piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 1 is a cross-sectional view of the piezoelectric transducer shown in FIG. 1 as seen from the direction of arrows II-II.
  • FIG. 5 is a cross-sectional view showing a state in which a lower electrode
  • FIG. 6 is a cross-sectional view showing a state in which an upper electrode layer is provided on the upper surface of the piezoelectric layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 5 is a cross-sectional view showing a state in which a part of the upper electrode layer is formed in the upper wiring layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 3 is a diagram showing a state in which a groove portion is formed in the piezoelectric layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 6 is a diagram showing a state in which a groove is formed in the lower electrode layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 5 is a diagram showing a state in which a recess is formed in the lower base portion in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. It is a top view which shows a part of membrane part of the piezoelectric transducer which concerns on a comparative example. It is a top view showing a part of membrane part of a piezoelectric transducer concerning an example. It is sectional drawing which shows the structure of the piezoelectric transducer which concerns on Embodiment 2 of this invention.
  • FIG. 9 is a diagram showing a state in which a groove is formed in the lower electrode layer in the method of manufacturing the piezoelectric transducer according to the second embodiment of the present invention.
  • FIG. 9 is a diagram showing a state in which a groove is formed in the active layer in the method of manufacturing the piezoelectric transducer according to the second embodiment of the present invention.
  • FIG. 11 is a diagram showing a state in which a recess is formed in the lower base portion in the method of manufacturing the piezoelectric transducer according to the second embodiment of the present invention.
  • FIG. 1 is a plan view showing the configuration of the piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 2 is a cross-sectional view of the piezoelectric transducer shown in FIG. 1 as seen in the direction of arrows II-II.
  • the piezoelectric transducer 100 includes a base portion 110 and a membrane portion 120.
  • the base 110 includes a lower base 111 and an upper base 112.
  • the upper base 112 is stacked on the lower base 111.
  • an opening is formed at the center of the lower base 111 and the upper base 112.
  • the recess 130 is formed from the lower surface side.
  • the lower base 111 is made of Si.
  • the upper base 112 is made of SiO 2 .
  • the membrane part 120 has a virtual circular outer shape when viewed from above and below.
  • the membrane part 120 is indirectly supported by the base part 110 and is located above the base part 110.
  • the membrane part 120 does not overlap the base part 110. That is, the membrane part 120 is located above the recess 130.
  • the end of the membrane part 120 and the end of the recess 130, that is, the inner peripheral end of the base 110 are substantially aligned when viewed from above and below.
  • the membrane part 120 is composed of a laminated body described later. A part of the laminated body extends from the membrane portion 120 to the outer peripheral side. The extending portion of the stacked body is located on the upper surface of the base 110. Thus, the membrane part 120 is indirectly supported by the base part 110.
  • the membrane part 120 includes a plate part 121, a base end part 122, and a connecting part 123.
  • the plate-like portion 121 has an outer peripheral side surface 121S when viewed from above and below.
  • the outer peripheral side surface 121S has a circular shape when viewed from above and below.
  • the outer peripheral side surface 121S may have a polygonal shape such as a rectangular shape when viewed from above and below.
  • the plate-shaped portion 121 is displaced in the vertical direction during driving.
  • the base end portion 122 is located on the outer peripheral side of the plate-like portion 121 when viewed from above and below and has an annular outer shape concentric with the plate-like portion 121.
  • the connecting portion 123 is a region that occupies a portion from the outer peripheral side surface 121S of the plate-like portion 121 to the base end portion 122 in the membrane portion 120 when viewed from the up and down direction.
  • the connecting portion 123 connects the plate-shaped portion 121 and the base end portion 122 to each other.
  • the connecting portion 123 has a groove portion 124 formed in a concave shape from the upper surface side.
  • a plurality of groove portions 124 are formed in the connecting portion 123.
  • each of the plurality of groove portions 124 is formed so as to extend along the circumferential direction of the outer peripheral side surface 121S of the plate-shaped portion 121.
  • Each of the plurality of groove portions 124 is formed such that the radial width of the outer peripheral side surface 121S is substantially constant.
  • each of the four groove portions 124 located on the innermost peripheral side extends along the circumferential direction and is spaced from each other.
  • Each of the four groove portions 124 located on the innermost peripheral side is arranged such that the inner peripheral side end portion is located on the outer peripheral side surface 121S of the plate-shaped portion 121 when viewed in the vertical direction.
  • four groove portions 124 located on the innermost peripheral side are formed, but the number of groove portions 124 located on the innermost peripheral side is not limited to four and may be a plurality.
  • the four groove portions 124 located on the innermost peripheral side are spaced from each other so as to be displaced in the circumferential direction with respect to the groove portions 124 located on the innermost peripheral side on the same circumference on the outer peripheral side.
  • Four groove portions 124 are arranged. Specifically, the four groove portions 124 are arranged so that the corresponding groove portions 124 are located in the region on the outer peripheral side of the gap portion located between the groove portions 124 located on the innermost peripheral side.
  • each of the four groove portions 124 located on the outermost peripheral side extends along the circumferential direction and is spaced from each other.
  • Each of the four groove portions 124 located on the outermost peripheral side is arranged such that the outer peripheral side end portion is located on the same circumference as the inner peripheral side end portion of the base end portion 122 when viewed in the vertical direction.
  • four groove portions 124 located on the outermost peripheral side are formed, but the number of groove portions 124 located on the outermost peripheral side is not limited to four, and may be any number.
  • the four groove portions 124 located on the outermost peripheral side are spaced apart from each other by a distance of 4 so as to be displaced in the circumferential direction with respect to the groove portions 124 located on the outermost peripheral side on the same circumference on the inner peripheral side.
  • One groove portion 124 is arranged.
  • four groove portions 124 are arranged such that the corresponding groove portions 124 are located in the region on the inner peripheral side of the gap portion located between the groove portions 124 located on the outermost peripheral side.
  • the groove portions 124 are arranged in a mesh shape.
  • the plurality of groove portions 124 are arranged in four rows along the circumferential direction, but the number of rows of the plurality of groove portions 124 in the circumferential direction may be two or more rows.
  • the plurality of groove portions 124 may be composed of a plurality of groove portions 124 located on the innermost peripheral side and a plurality of groove portions 124 located on the outermost peripheral side.
  • each sidewall surface of the plurality of groove portions 124 is composed of a piezoelectric layer and a lower electrode layer described later.
  • the bottom surface of each of the plurality of groove portions 124 is composed of the upper surface of the active layer described later.
  • the groove part 124 may penetrate the membrane part 120 in the up-down direction.
  • the plate portion 121 is connected to the connecting portion 123 over the entire thickness in the vertical direction as shown in FIG. It has one first connection region 121R.
  • the four first connection regions 121R are spaced from each other along the circumferential direction of the outer peripheral side surface 121S of the plate-shaped portion 121.
  • the first connection region 121R is adjacent to the gap portion located between the groove portions 124 located on the innermost peripheral side in the connection portion 123 when viewed from the up and down direction. Note that the number of the first connection regions 121R is not limited to four and may be any number.
  • the base end portion 122 has four second connection regions 122R that are connected to the connection portion 123 over the entire thickness in the vertical direction.
  • the four second connection regions 122R are spaced from each other along the circumferential direction.
  • the second connection region 122R is adjacent to the gap portion located between the groove portions 124 located on the outermost peripheral side in the connection portion 123 when viewed from the vertical direction. Note that the number of the second connection regions 122R is not limited to four and may be any number.
  • the connecting portion 123 is located on the outer peripheral side of the plate-like portion 121 from any first connecting area 121R among the four first connecting areas 121R.
  • Each of the eight virtual straight lines L extending and passing through any second connection region 122R among the four second connection regions 122R has a shape that is discontinuous by the three groove portions 124. ..
  • the number of the virtual straight lines L is not limited to eight, and may be any number.
  • the connecting portion 123 may have a shape that is discontinuous on each virtual straight line L due to at least one groove portion 124.
  • the plate-like portion 121 has a piezoelectric layer 101, an upper electrode layer 102, and a lower electrode layer 103.
  • the piezoelectric layer 101 is arranged on the entire plate-shaped portion 121 when viewed from the up and down direction.
  • the piezoelectric layer 101 may be made of a polycrystalline material or a single crystal material.
  • the piezoelectric layer 101 is made of lead zirconate titanate (PZT)-based ceramics, aluminum nitride (AlN), lithium niobate (LiNbO 3 ) or lithium tantalate (LiTaO 3 ).
  • the upper electrode layer 102 is arranged above the piezoelectric layer 101. As shown in FIG. 1, when viewed from above and below, the upper electrode layer 102 has a circular outer shape and is arranged so as to be concentric with the plate portion 121. The upper electrode layer 102 may have an outer shape that is substantially the same as the plate-shaped portion 121 when viewed from above and below.
  • the upper electrode layer 102 is made of a conductive material such as Pt.
  • An adhesion layer made of Ti or the like may be arranged between the upper electrode layer 102 and the piezoelectric layer 101.
  • the lower electrode layer 103 is arranged so as to face at least a part of the upper electrode layer 102 with the piezoelectric layer 101 interposed therebetween.
  • the lower electrode layer 103 has an outer shape that is substantially the same as the outer shape of the plate-shaped portion 121 when viewed in the vertical direction.
  • the lower electrode layer 103 may have an outer shape that is located inside the plate-shaped portion 121 when viewed in the vertical direction.
  • the lower electrode layer 103 is made of a conductive material such as Pt.
  • An adhesion layer made of Ti or the like may be arranged between the lower electrode layer 103 and the piezoelectric layer 101.
  • the plate-shaped portion 121 further has an active layer 104.
  • the active layer 104 is arranged below the lower electrode layer 103 in the plate portion 121.
  • the active layer 104 is made of Si.
  • An insulating layer made of SiO 2 or the like may be arranged between the lower electrode layer 103 and the active layer 104.
  • each of the connecting portion 123 and the base end portion 122 has an upper wiring layer 102x extending from the upper electrode layer 102.
  • the upper wiring layer 102x is arranged from the inner peripheral side to the outer peripheral side in the connecting portion 123 so as to bypass the plurality of groove portions 124.
  • the upper wiring layer 102x is connected to the upper electrode pad 102y arranged on the outer peripheral side of the base end portion 122 when viewed from above and below.
  • each of the connecting portion 123 and the base end portion 122 further has a piezoelectric layer 101, a lower electrode layer 103, and an active layer 104.
  • the portions forming each of the connecting portion 123 and the base end portion 122 are continuous with the portion forming the plate-like portion 121.
  • the laminated body including the piezoelectric layer 101, the lower electrode layer 103, and the active layer 104 extends to the outside of the base end portion 122 to form the base portion 110. Supported by.
  • the piezoelectric layer 101 extending from the base end portion 122 to the outer peripheral side is provided with an opening for exposing a part of the lower electrode layer 103 arranged on the lower side. ..
  • FIG. 3 is a cross-sectional view showing a state in which a lower electrode layer is provided on the upper surface of the active layer in the method for manufacturing a piezoelectric transducer according to the first embodiment of the present invention.
  • the lower electrode layer 103 is provided on the upper surface of the active layer 104 by a lift-off method, a plating method, an etching method, or the like.
  • the laminated body having the lower base 111, the upper base 112 and the active layer 104 is prepared in advance as a so-called SOI (Silicon on Insulator) substrate.
  • SOI Silicon on Insulator
  • FIG. 4 is a cross-sectional view showing a state in which the piezoelectric layer is provided on the upper surface of the lower electrode layer in the method for manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • the piezoelectric layer 101 is provided on the upper surface of the lower electrode layer 103 by a CVD (Chemical Vapor Deposition) method or a PVD (Physical Vapor Deposition) method.
  • FIG. 5 is a cross-sectional view showing a state in which an upper electrode layer is provided on the upper surface of the piezoelectric layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • the upper electrode layer 102 is provided on the upper surface of the piezoelectric layer 101 by a lift-off method, a plating method, an etching method, or the like.
  • FIG. 6 is a cross-sectional view showing a state in which a part of the upper electrode layer is formed in the upper wiring layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • the upper electrode layer 102 is patterned by a lift-off method or an etching method.
  • the outer shape of the upper electrode layer 102 is defined, and the upper wiring layer 102x and the upper electrode pad 102y are provided on the piezoelectric layer 101.
  • FIG. 7 is a diagram showing a state where grooves are formed in the piezoelectric layer in the method for manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • the piezoelectric layer 101 is patterned by a lift-off method or an etching method.
  • the groove portion 124 is formed in the piezoelectric layer 101.
  • an opening for exposing the lower electrode layer 103 may be formed together with the formation of the groove 124.
  • FIG. 8 is a diagram showing a state in which a groove is formed in the lower electrode layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • the lower electrode layer 103 is patterned by a lift-off method or an etching method.
  • the groove portion 124 is formed in the lower electrode layer 103.
  • FIG. 9 is a diagram showing a state in which a concave portion is formed in the lower base portion in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • Deep RIE Deep Reactive Ion Etching
  • the recess 130 is formed in the upper base 112 by performing deep reactive ion etching on the upper base 112 from the lower surface of the upper base 112. Through these steps, the membrane part 120 in the present embodiment is formed, and the piezoelectric transducer 100 according to the first embodiment of the present invention as shown in FIG. 2 is manufactured.
  • the operation of the piezoelectric transducer 100 according to the present embodiment during driving will be described.
  • a voltage is applied between the upper electrode pad 102y and the exposed lower electrode layer 103.
  • a voltage is applied to the piezoelectric layer 101 located between the upper electrode layer 102 and the lower electrode layer 103 in the plate-shaped portion 121 through each of the upper wiring layer 102x and the lower electrode layer 103.
  • the piezoelectric layer 101 constrained by the upper electrode layer 102, the lower electrode layer 103, and the active layer 104 is distorted, so that the membrane portion 120 flexurally vibrates vertically.
  • sound waves or ultrasonic waves are generated.
  • the piezoelectric transducer 100 When the piezoelectric transducer 100 according to the present embodiment detects a sound wave or an ultrasonic wave, the piezoelectric layer 101 is distorted due to bending vibration of the membrane portion 120 due to the sound wave or the ultrasonic wave, and the stress acting on the piezoelectric layer 101 at this time. Electric charges are thereby induced inside the piezoelectric layer 101. Thereby, the potential difference generated between the upper electrode layer 102 and the lower electrode layer 103 is detected from the upper electrode pad 102y and the exposed lower electrode layer 103. In this way, acoustic waves or ultrasonic waves can be detected by the piezoelectric transducer 100.
  • the plurality of groove portions 124 are formed in the connection portion 123, so that the residual stress generated in the membrane portion 120 can be relaxed, specifically, the plate portion. It is possible to prevent the residual stress generated in 121 from being applied to the base end portion 122 and the base portion 110 through the connection portion 123.
  • FIG. 10 is a plan view showing a part of the membrane portion of the piezoelectric transducer according to the comparative example.
  • the connection portion 923 of the piezoelectric transducer 900 according to the comparative example extends on the virtual straight line L extending from the first connection region 921R to the outer peripheral side of the plate-shaped portion 921 and passing through the second connection region 922R.
  • a part of the connection portion 923 linearly extends in the radial direction of the plate-shaped portion 921, and the first connection region 921R of the plate-shaped portion 921 and the second connection region 922R of the base end portion 922 are formed. And are connected to each other.
  • the residual stress S generated in the plate-shaped portion 921 is transferred from the first connection region 921R to the second connection region 922R through a part of the connection portion 923 that extends linearly. To work. Therefore, the residual stress S cannot be sufficiently relaxed by the groove portion 924 provided in the membrane portion, and the residual stress S causes the membrane portion to bend or the membrane portion to be pulled toward the outer peripheral side.
  • FIG. 11 is a plan view showing a part of the membrane portion of the piezoelectric transducer according to the example.
  • the connecting portion 123 of the piezoelectric transducer 100e according to the example all the virtual portions extending from the first connecting region 121R to the outer peripheral side of the plate-like portion 121 and passing through the second connecting region 122R.
  • At least one groove portion 124 is arranged on the straight line L. That is, all the virtual straight lines L intersect at least one groove portion 124. Therefore, the connecting portion 123 does not have a portion that linearly connects the first connecting region 121R and the second connecting region 122R.
  • the residual stress S generated in the plate-shaped portion 121 acts on the second connection region 122R, bypassing the groove portion 124, from the first connection region 121R.
  • the portion of the connection portion 123 around the groove portion 124 is deformed.
  • the residual stress S acting on the second connection region 122R is reduced by the deformation of the portion around the groove portion 124 in the connection portion 123.
  • the path through which the residual stress S is transmitted from the first connection region 121R to the second connection region 122R is lengthened, and at the portion around the groove portion 124 in the connection portion 123.
  • the residual stress S can be sufficiently relaxed.
  • the membrane part can be excited in a desired vibration mode, and a decrease in the vertical displacement of the membrane part can be suppressed. As a result, it is possible to suppress the deterioration of the input/output characteristics of the piezoelectric transducer 100e.
  • connection portion 123 extends from the arbitrary first connection region 121R of the plurality of first connection regions 121R to the outer peripheral side of the plate-shaped portion 121. Then, on each of a plurality of virtual straight lines L passing through any second connection region 122R among the plurality of second connection regions 122R, a shape that is discontinuous due to at least one groove portion 124 provided in the membrane unit 120 have.
  • the residual stress in the membrane portion 120 can be relieved by the groove portion 124 provided in the membrane portion 120 as described above. As a result, it is possible to suppress deterioration of the input/output characteristics of the piezoelectric transducer 100 due to the influence of residual stress.
  • the groove portions 124 are arranged in a mesh shape. Accordingly, the membrane portion 120 easily vibrates when a sound wave or an ultrasonic wave is generated and at the time of detecting a sound wave or an ultrasonic wave, so that the sensitivity of the piezoelectric transducer 100 can be increased.
  • the piezoelectric transducer according to the second embodiment of the present invention will be described below.
  • the piezoelectric transducer according to the second embodiment of the present invention is different from the piezoelectric transducer 100 in that the groove portion vertically penetrates the membrane portion. Therefore, the description of the same configuration as the piezoelectric transducer 100 according to the first embodiment of the present invention will not be repeated.
  • FIG. 12 is a cross-sectional view showing the configuration of the piezoelectric transducer according to the second embodiment of the present invention.
  • the sectional view of the piezoelectric transducer 200 shown in FIG. 12 is shown in the same sectional view as the sectional view of the piezoelectric transducer 100 shown in FIG.
  • the groove portion 224 penetrates the membrane portion 220 in the vertical direction.
  • the sidewall surface of each of the plurality of groove portions 224 is composed of the piezoelectric layer 201, the lower electrode layer 203, and the active layer 204.
  • FIG. 13 is a diagram showing a state in which a groove is formed in the lower electrode layer in the method for manufacturing the piezoelectric transducer according to the second embodiment of the present invention. Since the steps up to the step of forming the groove portion 224 in the lower electrode layer 203 shown in FIG. 13 are the same as the method for manufacturing the piezoelectric transducer 100 according to Embodiment 1 of the present invention shown in FIGS. Do not repeat.
  • FIG. 14 is a diagram showing a state in which a groove is formed in the active layer in the method of manufacturing the piezoelectric transducer according to the second embodiment of the present invention.
  • the active layer 204 is patterned by a lift-off method or an etching method.
  • the groove portion 224 is formed in the active layer 204.
  • FIG. 15 is a diagram showing a state in which a recess is formed in the lower base in the method for manufacturing a piezoelectric transducer according to the second embodiment of the present invention.
  • a recess 230 is formed in the lower base 111 by performing deep reactive ion etching on the lower base 111 from the lower surface side of the lower base 111.
  • the recess 230 is formed in the upper base 112 by performing deep reactive ion etching on the upper base 112 from the lower surface of the upper base 112. Through these steps, the membrane part 220 in the present embodiment is formed, and the piezoelectric transducer 200 according to the second embodiment of the present invention as shown in FIG. 12 is manufactured.
  • the groove portion 224 penetrates the membrane portion 220 in the vertical direction.
  • the peripheral portion of the groove 224 in the connecting portion 223 is more easily deformed, and the residual stress of the membrane portion 220 can be further alleviated.
  • 100, 100e, 200, 900 piezoelectric transducer 101, 201 piezoelectric layer, 102 upper electrode layer, 102x upper wiring layer, 102y upper electrode pad, 103, 203 lower electrode layer, 104, 204 active layer, 110 base, 111 lower Side base portion, 112 upper base portion, 120, 220 membrane portion, 121, 921 plate portion, 121R, 921R first connection area, 121S outer peripheral side surface, 122, 922 base end portion, 122R, 922R second connection area, 123, 223 , 923 connection part, 124, 224, 924 groove part, 130, 230 recessed part, L virtual straight line, S residual stress.

Abstract

A tabular part (121) has a plurality of first connecting regions (121R) connected to a connecting part (123) across the entire thickness in the vertical direction. The plurality of first connecting regions (121R) are located along the circumferential direction of an outer circumferential side face (121S) of the tabular part (121) by being spaced apart from each other. A base end part (122) has a plurality of second connecting regions (122R) connected to the connecting part (123) across the entire thickness in the vertical direction. The plurality of second connecting regions (122R) are located along the circumferential direction by being spaced apart from each other. The connecting part (123) has a shape that is made discontinuous by at least one groove (124) provided in a membrane part (120) on each of a plurality of virtual straight lines (L) extending from a discretionary first connecting region (121R) out of the plurality of first connecting regions (121R) toward the outer circumferential side of the tabular part (21) and passing through a discretionary second connecting region (122R) out of the plurality of second connecting regions (122R).

Description

圧電トランスデューサPiezoelectric transducer
　本発明は、圧電トランスデューサに関する。 The present invention relates to a piezoelectric transducer.
　トランスデューサにおけるメンブレン構造の構成を開示した先行文献として、特開２００６－３１９７１２号公報(特許文献１)がある。特許文献１には、静電容量型超音波振動子が記載されている。静電容量型超音波振動子は、振動子セルから構成された振動子エレメントを集積してなる。振動子セルは、シリコン基板と、第１の電極と、第２の電極と、メンブレンと、メンブレン支持部とからなる。第１の電極は、シリコン基板の上面に配設されている。第２の電極は、第１の電極と対向し所定の空隙を隔てて配設されている。メンブレンは、第２の電極を支持している。メンブレン支持部は、メンブレンを支持している。メンブレンの端部は、メンブレンの中央部よりも相対的に変形しやすくする構造を有している。当該構造は、メンブレンの端部に設けられた少なくとも一列の溝である。メンブレンは略円形状をしており、溝は、メンブレン周縁部近傍に略同心円状に設けられている溝列である。溝は、略円弧状に複数形成されている。 As a prior document disclosing the structure of the membrane structure in the transducer, there is JP-A-2006-319712 (Patent Document 1). Patent Document 1 describes a capacitive ultrasonic transducer. The capacitive ultrasonic transducer is formed by integrating transducer elements composed of transducer cells. The oscillator cell includes a silicon substrate, a first electrode, a second electrode, a membrane, and a membrane supporting portion. The first electrode is provided on the upper surface of the silicon substrate. The second electrode faces the first electrode and is arranged with a predetermined gap. The membrane supports the second electrode. The membrane supporting portion supports the membrane. The end portion of the membrane has a structure that makes it relatively easier to deform than the center portion of the membrane. The structure is at least one row of grooves provided at the end of the membrane. The membrane has a substantially circular shape, and the groove is a groove array provided in a substantially concentric shape in the vicinity of the peripheral edge of the membrane. A plurality of grooves are formed in a substantially arc shape.
特開２００６－３１９７１２号公報JP, 2006-319712, A
　圧電トランスデューサにおいては、メンブレン部は、圧電体層、上部電極層および下部電極層の各々を有する。これらの層が形成された際に、メンブレン部に残留応力が生ずる場合がある。 In the piezoelectric transducer, the membrane part has each of a piezoelectric layer, an upper electrode layer and a lower electrode layer. When these layers are formed, residual stress may occur in the membrane part.
　特許文献１に記載されているメンブレン構造においては、メンブレン部の中央部とメンブレン支持部とが、溝が設けられていない領域によって直線的に互いに接続されている部分が存在する。この場合、メンブレン部に設けられている溝によって残留応力を十分に緩和することができず、メンブレン部に撓みが生ずる、または、メンブレン部が外周側に引っ張られることがある。その結果、圧電トランスデューサの駆動時に、メンブレン部を所望の振動モードで励振させることができない、または、メンブレン部の上下方向の変位量が低下する。ひいては、圧電トランスデューサの入出力特性が低下する。 In the membrane structure described in Patent Document 1, there is a portion where the central portion of the membrane portion and the membrane supporting portion are linearly connected to each other by a region where no groove is provided. In this case, the residual stress cannot be sufficiently relieved by the groove provided in the membrane portion, and the membrane portion may be bent or the membrane portion may be pulled toward the outer peripheral side. As a result, when the piezoelectric transducer is driven, the membrane part cannot be excited in a desired vibration mode, or the vertical displacement of the membrane part is reduced. As a result, the input/output characteristics of the piezoelectric transducer deteriorate.
　本発明は上記の問題点に鑑みてなされたものであり、残留応力の影響による入出力特性の低下を抑制することができる、圧電トランスデューサを提供することを目的とする。 The present invention has been made in view of the above problems, and an object of the present invention is to provide a piezoelectric transducer capable of suppressing a decrease in input/output characteristics due to the influence of residual stress.
　本発明に基づく圧電トランスデューサは、基部と、メンブレン部とを備えている。メンブレン部は、基部に間接的に支持され、基部より上側に位置している。メンブレン部は、基部に重なっていない。メンブレン部は、板状部と、基端部と、接続部とを含んでいる。板状部は、上下方向から見たときに、外周側面を有している。基端部は、上下方向から見たときに、板状部の外周側に位置して、板状部と同心円状の円環状の外形を有している。接続部は、板状部と基端部とを互いに接続する。板状部は、圧電体層と、上部電極層と、下部電極層とを有している。上部電極層は圧電体層の上側に配置されている。下部電極層は、圧電体層を挟んで上部電極層の少なくとも一部に対向するように配置されている。板状部は、接続部と上下方向の厚さ全体に亘って接続されている複数の第１接続領域を有している。複数の第１接続領域は、板状部の外周側面の周方向に沿って互いに間隔をあけて位置している。基端部は、接続部と上下方向の厚さ全体に亘って接続されている複数の第２接続領域を有している。複数の第２接続領域は、上記周方向に沿って互いに間隔をあけて位置している。接続部は、複数の第１接続領域のうちの任意の第１接続領域から、板状部の外周側に延在して複数の第２接続領域のうちの任意の第２接続領域を通過する複数の仮想直線上の各々において、メンブレン部に設けられた少なくとも１つの溝部によって不連続となる形状を有している。 The piezoelectric transducer according to the present invention includes a base portion and a membrane portion. The membrane part is indirectly supported by the base part and is located above the base part. The membrane part does not overlap the base part. The membrane part includes a plate-shaped part, a base end part, and a connection part. The plate-shaped portion has an outer peripheral side surface when viewed from above and below. The base end portion is located on the outer peripheral side of the plate-shaped portion and has an annular outer shape concentric with the plate-shaped portion when viewed in the vertical direction. The connecting portion connects the plate-shaped portion and the base end portion to each other. The plate-shaped portion has a piezoelectric layer, an upper electrode layer, and a lower electrode layer. The upper electrode layer is arranged above the piezoelectric layer. The lower electrode layer is arranged so as to face at least a part of the upper electrode layer with the piezoelectric layer interposed therebetween. The plate-shaped portion has a plurality of first connection regions connected to the connection portion over the entire thickness in the vertical direction. The plurality of first connection regions are located at intervals along the circumferential direction of the outer peripheral side surface of the plate-shaped portion. The base end portion has a plurality of second connection regions connected to the connection portion over the entire thickness in the vertical direction. The plurality of second connection regions are located at intervals in the circumferential direction. The connecting portion extends from the arbitrary first connecting area of the plurality of first connecting areas to the outer peripheral side of the plate-shaped portion and passes through the arbitrary second connecting area of the plurality of second connecting areas. Each of the plurality of virtual straight lines has a shape that is discontinuous due to at least one groove portion provided in the membrane portion.
　本発明によれば、圧電トランスデューサにおいて、残留応力の影響による入出力特性の低下を抑制することができる。 According to the present invention, it is possible to suppress the deterioration of the input/output characteristics due to the influence of the residual stress in the piezoelectric transducer.
本発明の実施形態１に係る圧電トランスデューサの構成を示す平面図である。FIG. 3 is a plan view showing the configuration of the piezoelectric transducer according to the first embodiment of the present invention. 図１に示した圧電トランスデューサについてＩＩ－ＩＩ線矢印方向から見た断面図である。FIG. 2 is a cross-sectional view of the piezoelectric transducer shown in FIG. 1 as seen from the direction of arrows II-II. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、活性層の上面に下部電極層を設けた状態を示す断面図である。FIG. 5 is a cross-sectional view showing a state in which a lower electrode layer is provided on the upper surface of the active layer in the method for manufacturing the piezoelectric transducer according to the first embodiment of the present invention. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、下部電極層の上面に圧電体層を設けた状態を示す断面図である。FIG. 3 is a cross-sectional view showing a state in which a piezoelectric layer is provided on the upper surface of a lower electrode layer in the method for manufacturing a piezoelectric transducer according to the first embodiment of the present invention. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、圧電体層の上面に上部電極層を設けた状態を示す断面図である。FIG. 6 is a cross-sectional view showing a state in which an upper electrode layer is provided on the upper surface of the piezoelectric layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、上部電極層の一部を上部配線層に形成した状態を示す断面図である。FIG. 5 is a cross-sectional view showing a state in which a part of the upper electrode layer is formed in the upper wiring layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、圧電体層に溝部を形成した状態を示す図である。FIG. 3 is a diagram showing a state in which a groove portion is formed in the piezoelectric layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、下部電極層に溝部を形成した状態を示す図である。FIG. 6 is a diagram showing a state in which a groove is formed in the lower electrode layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、下側基部に凹部が形成された状態を示す図である。FIG. 5 is a diagram showing a state in which a recess is formed in the lower base portion in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. 比較例に係る圧電トランスデューサのメンブレン部の一部を示す平面図である。It is a top view which shows a part of membrane part of the piezoelectric transducer which concerns on a comparative example. 実施例に係る圧電トランスデューサのメンブレン部の一部を示す平面図である。It is a top view showing a part of membrane part of a piezoelectric transducer concerning an example. 本発明の実施形態２に係る圧電トランスデューサの構成を示す断面図である。It is sectional drawing which shows the structure of the piezoelectric transducer which concerns on Embodiment 2 of this invention. 本発明の実施形態２に係る圧電トランスデューサの製造方法において、下部電極層に溝部を形成した状態を示す図である。FIG. 9 is a diagram showing a state in which a groove is formed in the lower electrode layer in the method of manufacturing the piezoelectric transducer according to the second embodiment of the present invention. 本発明の実施形態２に係る圧電トランスデューサの製造方法において、活性層に溝部を形成した状態を示す図である。FIG. 9 is a diagram showing a state in which a groove is formed in the active layer in the method of manufacturing the piezoelectric transducer according to the second embodiment of the present invention. 本発明の実施形態２に係る圧電トランスデューサの製造方法において、下側基部に凹部が形成された状態を示す図である。FIG. 11 is a diagram showing a state in which a recess is formed in the lower base portion in the method of manufacturing the piezoelectric transducer according to the second embodiment of the present invention.
　以下、本発明の各実施形態に係る圧電トランスデューサについて図面を参照して説明する。以下の実施形態の説明においては、図中の同一または相当部分には同一符号を付して、その説明は繰り返さない。 A piezoelectric transducer according to each embodiment of the present invention will be described below with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the drawings will be denoted by the same reference numerals and the description thereof will not be repeated.
　(実施形態１)
　図１は、本発明の実施形態１に係る圧電トランスデューサの構成を示す平面図である。図２は、図１に示した圧電トランスデューサについてＩＩ－ＩＩ線矢印方向から見た断面図である。 (Embodiment 1)
FIG. 1 is a plan view showing the configuration of the piezoelectric transducer according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the piezoelectric transducer shown in FIG. 1 as seen in the direction of arrows II-II.
　図１および図２に示すように、本発明の実施形態１に係る圧電トランスデューサ１００は、基部１１０と、メンブレン部１２０とを備えている。 As shown in FIGS. 1 and 2, the piezoelectric transducer 100 according to the first embodiment of the present invention includes a base portion 110 and a membrane portion 120.
　図２に示すように、基部１１０は、下側基部１１１と上側基部１１２とを含んでいる。上側基部１１２は、下側基部１１１上に積層されている。上下方向から見たときに、下側基部１１１および上側基部１１２の中央には開口部が形成されている。これにより、本実施形態に係る圧電トランスデューサ１００においては、下面側から凹部１３０が形成されている。 As shown in FIG. 2, the base 110 includes a lower base 111 and an upper base 112. The upper base 112 is stacked on the lower base 111. When viewed from above and below, an opening is formed at the center of the lower base 111 and the upper base 112. Thereby, in the piezoelectric transducer 100 according to the present embodiment, the recess 130 is formed from the lower surface side.
　本実施形態において、下側基部１１１は、Ｓｉで構成されている。上側基部１１２はＳｉＯ2で構成されている。 In this embodiment, the lower base 111 is made of Si. The upper base 112 is made of SiO 2 .
　図１に示すように、メンブレン部１２０は、上下方向から見たときに、仮想円形形状の外形を有している。 As shown in FIG. 1, the membrane part 120 has a virtual circular outer shape when viewed from above and below.
　図２に示すように、メンブレン部１２０は、基部１１０に間接的に支持され、基部１１０より上側に位置している。メンブレン部１２０は、基部１１０に重なっていない。すなわち、メンブレン部１２０は、凹部１３０の上方に位置している。本実施形態においては、上下方向から見たときに、メンブレン部１２０の端部と、凹部１３０の端部すなわち基部１１０の内周端部とは略一致している。 As shown in FIG. 2, the membrane part 120 is indirectly supported by the base part 110 and is located above the base part 110. The membrane part 120 does not overlap the base part 110. That is, the membrane part 120 is located above the recess 130. In the present embodiment, the end of the membrane part 120 and the end of the recess 130, that is, the inner peripheral end of the base 110 are substantially aligned when viewed from above and below.
　図２に示すように、メンブレン部１２０は、後述する積層体で構成されている。積層体の一部は、メンブレン部１２０から外周側に延出している。積層体の延出している部分が、基部１１０の上面に位置している。このように、メンブレン部１２０は、基部１１０に間接的に支持されている。 As shown in FIG. 2, the membrane part 120 is composed of a laminated body described later. A part of the laminated body extends from the membrane portion 120 to the outer peripheral side. The extending portion of the stacked body is located on the upper surface of the base 110. Thus, the membrane part 120 is indirectly supported by the base part 110.
　図１および図２に示すように、メンブレン部１２０は、板状部１２１と、基端部１２２と、接続部１２３とを含んでいる。 As shown in FIGS. 1 and 2, the membrane part 120 includes a plate part 121, a base end part 122, and a connecting part 123.
　図１に示すように、板状部１２１は、上下方向から見たときに、外周側面１２１Ｓを有している。本実施形態においては、外周側面１２１Ｓは、上下方向から見たときに、円形状である。外周側面１２１Ｓは、上下方向から見たときに、矩形状などの多角形状であってもよい。本実施形態に係る圧電トランスデューサ１００においては、駆動時において、板状部１２１が上下方向に変位する。 As shown in FIG. 1, the plate-like portion 121 has an outer peripheral side surface 121S when viewed from above and below. In the present embodiment, the outer peripheral side surface 121S has a circular shape when viewed from above and below. The outer peripheral side surface 121S may have a polygonal shape such as a rectangular shape when viewed from above and below. In the piezoelectric transducer 100 according to this embodiment, the plate-shaped portion 121 is displaced in the vertical direction during driving.
　基端部１２２は、上下方向から見たときに、板状部１２１の外周側に位置して、板状部１２１と同心円状の円環状の外形を有している。 The base end portion 122 is located on the outer peripheral side of the plate-like portion 121 when viewed from above and below and has an annular outer shape concentric with the plate-like portion 121.
　接続部１２３は、上下方向から見たときに、メンブレン部１２０において板状部１２１の外周側面１２１Ｓから基端部１２２までの間を占める領域である。接続部１２３は、板状部１２１と基端部１２２とを互いに接続する。 The connecting portion 123 is a region that occupies a portion from the outer peripheral side surface 121S of the plate-like portion 121 to the base end portion 122 in the membrane portion 120 when viewed from the up and down direction. The connecting portion 123 connects the plate-shaped portion 121 and the base end portion 122 to each other.
　図１および図２に示すように、接続部１２３においては、上面側から凹状に形成された溝部１２４が形成されている。本実施形態においては、接続部１２３に複数の溝部１２４が形成されている。 As shown in FIGS. 1 and 2, the connecting portion 123 has a groove portion 124 formed in a concave shape from the upper surface side. In this embodiment, a plurality of groove portions 124 are formed in the connecting portion 123.
　図１に示すように、本実施形態において、複数の溝部１２４の各々は、板状部１２１の外周側面１２１Ｓの周方向に沿って延在するように形成されている。複数の溝部１２４の各々は、外周側面１２１Ｓの径方向における幅が略一定となるように形成されている。 As shown in FIG. 1, in the present embodiment, each of the plurality of groove portions 124 is formed so as to extend along the circumferential direction of the outer peripheral side surface 121S of the plate-shaped portion 121. Each of the plurality of groove portions 124 is formed such that the radial width of the outer peripheral side surface 121S is substantially constant.
　接続部１２３において、最内周側に位置する４つの溝部１２４の各々は、上記周方向に沿って延在し、かつ、互いに間隔をあけて位置している。最内周側に位置する４つの溝部１２４の各々は、上下方向から見たときに、内周側端部が板状部１２１の外周側面１２１Ｓ上に位置するように配置されている。本実施形態においては、最内周側に位置する溝部１２４が４つ形成されているが、最内周側に位置する溝部１２４の数は、４つに限られず、複数であればよい。 In the connecting portion 123, each of the four groove portions 124 located on the innermost peripheral side extends along the circumferential direction and is spaced from each other. Each of the four groove portions 124 located on the innermost peripheral side is arranged such that the inner peripheral side end portion is located on the outer peripheral side surface 121S of the plate-shaped portion 121 when viewed in the vertical direction. In the present embodiment, four groove portions 124 located on the innermost peripheral side are formed, but the number of groove portions 124 located on the innermost peripheral side is not limited to four and may be a plurality.
　本実施形態においては、最内周側に位置する４つの溝部１２４の外周側の同一円周上において最内周側に位置する溝部１２４に対して周方向にずれるように、互いに間隔を開けて４つの溝部１２４が配置されている。具体的には、最内周側に位置する溝部１２４同士の間に位置する間隙部の外周側の領域に、対応する溝部１２４が位置するように、４つの溝部１２４が配置されている。 In the present embodiment, the four groove portions 124 located on the innermost peripheral side are spaced from each other so as to be displaced in the circumferential direction with respect to the groove portions 124 located on the innermost peripheral side on the same circumference on the outer peripheral side. Four groove portions 124 are arranged. Specifically, the four groove portions 124 are arranged so that the corresponding groove portions 124 are located in the region on the outer peripheral side of the gap portion located between the groove portions 124 located on the innermost peripheral side.
　接続部１２３において、最外周側に位置する４つの溝部１２４の各々は、上記周方向に沿って延在し、かつ、互いに間隔をあけて位置している。最外周側に位置する４つの溝部１２４の各々は、上下方向から見たときに、外周側端部が基端部１２２の内周側端部と同一円周上に位置するように配置されている。本実施形態においては、最外周側に位置する溝部１２４が４つ形成されているが、最外周側に位置する溝部１２４の数は、４つに限られず、複数であればよい。 In the connecting portion 123, each of the four groove portions 124 located on the outermost peripheral side extends along the circumferential direction and is spaced from each other. Each of the four groove portions 124 located on the outermost peripheral side is arranged such that the outer peripheral side end portion is located on the same circumference as the inner peripheral side end portion of the base end portion 122 when viewed in the vertical direction. There is. In the present embodiment, four groove portions 124 located on the outermost peripheral side are formed, but the number of groove portions 124 located on the outermost peripheral side is not limited to four, and may be any number.
　本実施形態においては、最外周側に位置する４つの溝部１２４の内周側の同一円周上において最外周側に位置する溝部１２４に対して周方向にずれるように、互いに間隔をあけて４つの溝部１２４が配置されている。具体的には、最外周側に位置する溝部１２４同士の間に位置する間隙部の内周側の領域に、対応する溝部１２４が位置するように、４つの溝部１２４が配置されている。 In the present embodiment, the four groove portions 124 located on the outermost peripheral side are spaced apart from each other by a distance of 4 so as to be displaced in the circumferential direction with respect to the groove portions 124 located on the outermost peripheral side on the same circumference on the inner peripheral side. One groove portion 124 is arranged. Specifically, four groove portions 124 are arranged such that the corresponding groove portions 124 are located in the region on the inner peripheral side of the gap portion located between the groove portions 124 located on the outermost peripheral side.
　上記のように、本実施形態において、溝部１２４は、メッシュ状に配置されている。なお、本実施形態において、複数の溝部１２４は、上記周方向に沿って４列となるように配置されているが、上記周方向における複数の溝部１２４の列の数は、２列以上であれば特に限定されない。すなわち、複数の溝部１２４は、最内周側に位置する複数の溝部１２４と最外周側に位置する複数の溝部１２４とから構成されていてもよい。 As described above, in this embodiment, the groove portions 124 are arranged in a mesh shape. In addition, in the present embodiment, the plurality of groove portions 124 are arranged in four rows along the circumferential direction, but the number of rows of the plurality of groove portions 124 in the circumferential direction may be two or more rows. There is no particular limitation. That is, the plurality of groove portions 124 may be composed of a plurality of groove portions 124 located on the innermost peripheral side and a plurality of groove portions 124 located on the outermost peripheral side.
　図２に示すように、本実施形態において、複数の溝部１２４の各々の側壁面は、後述する圧電体層および下部電極層で構成されている。複数の溝部１２４の各々の底面は、後述する活性層の上面で構成されている。なお、溝部１２４は、メンブレン部１２０を上下方向に貫通していてもよい。 As shown in FIG. 2, in the present embodiment, each sidewall surface of the plurality of groove portions 124 is composed of a piezoelectric layer and a lower electrode layer described later. The bottom surface of each of the plurality of groove portions 124 is composed of the upper surface of the active layer described later. In addition, the groove part 124 may penetrate the membrane part 120 in the up-down direction.
　上記のように、メンブレン部１２０に溝部１２４が設けられていることにより、図１に示すように、板状部１２１は、接続部１２３と上下方向の厚さ全体に亘って接続されている４つの第１接続領域１２１Ｒを有している。４つの第１接続領域１２１Ｒは、板状部１２１の外周側面１２１Ｓの周方向に沿って互いに間隔をあけて位置している。 As described above, since the groove portion 124 is provided in the membrane portion 120, the plate portion 121 is connected to the connecting portion 123 over the entire thickness in the vertical direction as shown in FIG. It has one first connection region 121R. The four first connection regions 121R are spaced from each other along the circumferential direction of the outer peripheral side surface 121S of the plate-shaped portion 121.
　第１接続領域１２１Ｒは、上下方向から見たときに、接続部１２３において最内周側に位置する溝部１２４同士の間に位置する間隙部と隣接している。なお、第１接続領域１２１Ｒの数は、４つに限られず、複数であればよい。 The first connection region 121R is adjacent to the gap portion located between the groove portions 124 located on the innermost peripheral side in the connection portion 123 when viewed from the up and down direction. Note that the number of the first connection regions 121R is not limited to four and may be any number.
　図１に示すように、基端部１２２は、接続部１２３と上下方向の厚さ全体に亘って接続されている４つの第２接続領域１２２Ｒを有している。４つの第２接続領域１２２Ｒは、上記周方向に沿って互いに間隔をあけて位置している。 As shown in FIG. 1, the base end portion 122 has four second connection regions 122R that are connected to the connection portion 123 over the entire thickness in the vertical direction. The four second connection regions 122R are spaced from each other along the circumferential direction.
　第２接続領域１２２Ｒは、上下方向から見たときに、接続部１２３において最外周側に位置する溝部１２４同士の間に位置する間隙部と隣接している。なお、第２接続領域１２２Ｒの数は、４つに限られず、複数であればよい。 The second connection region 122R is adjacent to the gap portion located between the groove portions 124 located on the outermost peripheral side in the connection portion 123 when viewed from the vertical direction. Note that the number of the second connection regions 122R is not limited to four and may be any number.
　図１に示すように、本実施形態に係る圧電トランスデューサ１００においては、接続部１２３は、４つの第１接続領域１２１Ｒのうちの任意の第１接続領域１２１Ｒから、板状部１２１の外周側に延在して４つの第２接続領域１２２Ｒのうちの任意の第２接続領域１２２Ｒを通過する８本の仮想直線Ｌ上の各々において、３つの溝部１２４によって不連続となる形状を有している。ただし、上記仮想直線Ｌの数は、８本に限られず、複数であればよい。また、接続部１２３は、各仮想直線Ｌ上において少なくとも１つの溝部１２４によって不連続となる形状を有していればよい。 As shown in FIG. 1, in the piezoelectric transducer 100 according to the present embodiment, the connecting portion 123 is located on the outer peripheral side of the plate-like portion 121 from any first connecting area 121R among the four first connecting areas 121R. Each of the eight virtual straight lines L extending and passing through any second connection region 122R among the four second connection regions 122R has a shape that is discontinuous by the three groove portions 124. .. However, the number of the virtual straight lines L is not limited to eight, and may be any number. Further, the connecting portion 123 may have a shape that is discontinuous on each virtual straight line L due to at least one groove portion 124.
　次に、板状部１２１、基端部１２２および接続部１２３の各々を構成する積層体について説明する。 Next, the laminated body that constitutes each of the plate-like portion 121, the base end portion 122, and the connecting portion 123 will be described.
　図２に示すように、板状部１２１は、圧電体層１０１と、上部電極層１０２と、下部電極層１０３とを有している。 As shown in FIG. 2, the plate-like portion 121 has a piezoelectric layer 101, an upper electrode layer 102, and a lower electrode layer 103.
　圧電体層１０１は、上下方向から見たときに、板状部１２１の全体に配置されている。圧電体層１０１は、多結晶材料で構成されていてもよいし、単結晶材料で構成されていてもよい。圧電体層１０１は、チタン酸ジルコン酸鉛(ＰＺＴ)系のセラミックス、窒化アルミニウム(ＡｌＮ)、ニオブ酸リチウム(ＬｉＮｂＯ3)またはタンタル酸リチウム(ＬｉＴａＯ3)などで構成されている。 The piezoelectric layer 101 is arranged on the entire plate-shaped portion 121 when viewed from the up and down direction. The piezoelectric layer 101 may be made of a polycrystalline material or a single crystal material. The piezoelectric layer 101 is made of lead zirconate titanate (PZT)-based ceramics, aluminum nitride (AlN), lithium niobate (LiNbO 3 ) or lithium tantalate (LiTaO 3 ).
　図２に示すように、上部電極層１０２は圧電体層１０１の上側に配置されている。図１に示すように、上下方向から見たときに、上部電極層１０２は円形形状の外形を有しており、板状部１２１と同心円状となるように配置されている。上部電極層１０２は、上下方向から見たときに、板状部１２１と略同一の外形を有していてもよい。 As shown in FIG. 2, the upper electrode layer 102 is arranged above the piezoelectric layer 101. As shown in FIG. 1, when viewed from above and below, the upper electrode layer 102 has a circular outer shape and is arranged so as to be concentric with the plate portion 121. The upper electrode layer 102 may have an outer shape that is substantially the same as the plate-shaped portion 121 when viewed from above and below.
　上部電極層１０２は、Ｐｔなどの導電性を有する材料で構成されている。上部電極層１０２と圧電体層１０１との間に、Ｔｉなどで構成された密着層が配置されていてもよい。 The upper electrode layer 102 is made of a conductive material such as Pt. An adhesion layer made of Ti or the like may be arranged between the upper electrode layer 102 and the piezoelectric layer 101.
　図２に示すように、下部電極層１０３は、圧電体層１０１を挟んで上部電極層１０２の少なくとも一部に対向するように配置されている。図２に示すように、本実施形態においては、上下方向から見たときに、下部電極層１０３は板状部１２１の外形と略同一の外形を有している。下部電極層１０３は、上下方向から見たときに、板状部１２１より内側に位置する外形を有していてもよい。 As shown in FIG. 2, the lower electrode layer 103 is arranged so as to face at least a part of the upper electrode layer 102 with the piezoelectric layer 101 interposed therebetween. As shown in FIG. 2, in the present embodiment, the lower electrode layer 103 has an outer shape that is substantially the same as the outer shape of the plate-shaped portion 121 when viewed in the vertical direction. The lower electrode layer 103 may have an outer shape that is located inside the plate-shaped portion 121 when viewed in the vertical direction.
　下部電極層１０３は、Ｐｔなどの導電性を有する材料で構成されている。下部電極層１０３と圧電体層１０１との間に、Ｔｉなどで構成された密着層が配置されていてもよい。 The lower electrode layer 103 is made of a conductive material such as Pt. An adhesion layer made of Ti or the like may be arranged between the lower electrode layer 103 and the piezoelectric layer 101.
　図２に示すように、本実施形態において、板状部１２１は、さらに活性層１０４を有している。活性層１０４は、板状部１２１において下部電極層１０３の下側に配置されている。本実施形態において、活性層１０４はＳｉで構成されている。下部電極層１０３と活性層１０４との間には、ＳｉＯ2などで構成された絶縁層が配置されていてもよい。 As shown in FIG. 2, in the present embodiment, the plate-shaped portion 121 further has an active layer 104. The active layer 104 is arranged below the lower electrode layer 103 in the plate portion 121. In this embodiment, the active layer 104 is made of Si. An insulating layer made of SiO 2 or the like may be arranged between the lower electrode layer 103 and the active layer 104.
　図１および図２に示すように、本実施形態において、接続部１２３および基端部１２２の各々は、上部電極層１０２から延設された上部配線層１０２ｘを有している。図１に示すように、上部配線層１０２ｘは、接続部１２３において、複数の溝部１２４を迂回するようにして、内周側から外周側にかけて配設されている。 As shown in FIGS. 1 and 2, in the present embodiment, each of the connecting portion 123 and the base end portion 122 has an upper wiring layer 102x extending from the upper electrode layer 102. As shown in FIG. 1, the upper wiring layer 102x is arranged from the inner peripheral side to the outer peripheral side in the connecting portion 123 so as to bypass the plurality of groove portions 124.
　上部配線層１０２ｘは、上下方向から見たときに、基端部１２２より外周側に配置された上部電極パッド１０２ｙに接続されている。 The upper wiring layer 102x is connected to the upper electrode pad 102y arranged on the outer peripheral side of the base end portion 122 when viewed from above and below.
　図２に示すように、本実施形態においては、接続部１２３および基端部１２２の各々は、さらに、圧電体層１０１、下部電極層１０３および活性層１０４を有している。これらの層において、接続部１２３および基端部１２２の各々を構成している部分は、板状部１２１を構成している部分と連続している。 As shown in FIG. 2, in the present embodiment, each of the connecting portion 123 and the base end portion 122 further has a piezoelectric layer 101, a lower electrode layer 103, and an active layer 104. In these layers, the portions forming each of the connecting portion 123 and the base end portion 122 are continuous with the portion forming the plate-like portion 121.
　図１および図２に示すように、本実施形態においては、圧電体層１０１、下部電極層１０３および活性層１０４によって構成される積層体は、基端部１２２より外側に延出して、基部１１０に支持されている。 As shown in FIG. 1 and FIG. 2, in the present embodiment, the laminated body including the piezoelectric layer 101, the lower electrode layer 103, and the active layer 104 extends to the outside of the base end portion 122 to form the base portion 110. Supported by.
　図１に示すように、基端部１２２より外周側に延出した圧電体層１０１には、下側に配置された下部電極層１０３の一部を露出させるための開口部が形成されている。 As shown in FIG. 1, the piezoelectric layer 101 extending from the base end portion 122 to the outer peripheral side is provided with an opening for exposing a part of the lower electrode layer 103 arranged on the lower side. ..
　以下、本発明の実施形態１に係る圧電トランスデューサ１００の製造方法について説明する。 Hereinafter, a method for manufacturing the piezoelectric transducer 100 according to the first embodiment of the present invention will be described.
　図３は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、活性層の上面に下部電極層を設けた状態を示す断面図である。図３に示すように、リフトオフ法、めっき法、または、エッチング法などにより、活性層１０４の上面に下部電極層１０３を設ける。 FIG. 3 is a cross-sectional view showing a state in which a lower electrode layer is provided on the upper surface of the active layer in the method for manufacturing a piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 3, the lower electrode layer 103 is provided on the upper surface of the active layer 104 by a lift-off method, a plating method, an etching method, or the like.
　なお、本実施形態において、下側基部１１１、上側基部１１２および活性層１０４を有する積層体は、いわゆるＳＯＩ(Silicon　on　Insulator)基板として予め準備される。 In the present embodiment, the laminated body having the lower base 111, the upper base 112 and the active layer 104 is prepared in advance as a so-called SOI (Silicon on Insulator) substrate.
　図４は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、下部電極層の上面に圧電体層を設けた状態を示す断面図である。図４に示すように、ＣＶＤ(Chemical　Vapor　Deposition)法またはＰＶＤ(Physical　Vapor　Deposition)法などにより、下部電極層１０３の上面に、圧電体層１０１を設ける。 FIG. 4 is a cross-sectional view showing a state in which the piezoelectric layer is provided on the upper surface of the lower electrode layer in the method for manufacturing the piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 4, the piezoelectric layer 101 is provided on the upper surface of the lower electrode layer 103 by a CVD (Chemical Vapor Deposition) method or a PVD (Physical Vapor Deposition) method.
　図５は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、圧電体層の上面に上部電極層を設けた状態を示す断面図である。図５に示すように、リフトオフ法、めっき法、または、エッチング法などにより、圧電体層１０１の上面に、上部電極層１０２を設ける。 FIG. 5 is a cross-sectional view showing a state in which an upper electrode layer is provided on the upper surface of the piezoelectric layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 5, the upper electrode layer 102 is provided on the upper surface of the piezoelectric layer 101 by a lift-off method, a plating method, an etching method, or the like.
　図６は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、上部電極層の一部を上部配線層に形成した状態を示す断面図である。図６に示すように、リフトオフ法またはエッチング法などにより、上部電極層１０２をパターニングする。これにより、上部電極層１０２の外形が画定されるとともに、圧電体層１０１上に上部配線層１０２ｘおよび上部電極パッド１０２ｙが設けられる。 FIG. 6 is a cross-sectional view showing a state in which a part of the upper electrode layer is formed in the upper wiring layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 6, the upper electrode layer 102 is patterned by a lift-off method or an etching method. As a result, the outer shape of the upper electrode layer 102 is defined, and the upper wiring layer 102x and the upper electrode pad 102y are provided on the piezoelectric layer 101.
　図７は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、圧電体層に溝部を形成した状態を示す図である。図７に示すように、リフトオフ法またはエッチング法などにより、圧電体層１０１をパターニングする。これにより、圧電体層１０１に溝部１２４が形成される。なお、圧電体層１０１においては、溝部１２４の形成とともに、下部電極層１０３を露出させるための開口部が形成されてもよい。 FIG. 7 is a diagram showing a state where grooves are formed in the piezoelectric layer in the method for manufacturing the piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 7, the piezoelectric layer 101 is patterned by a lift-off method or an etching method. As a result, the groove portion 124 is formed in the piezoelectric layer 101. In the piezoelectric layer 101, an opening for exposing the lower electrode layer 103 may be formed together with the formation of the groove 124.
　図８は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、下部電極層に溝部を形成した状態を示す図である。図８に示すように、リフトオフ法またはエッチング法などにより、下部電極層１０３をパターニングする。これにより、下部電極層１０３に溝部１２４が形成される。 FIG. 8 is a diagram showing a state in which a groove is formed in the lower electrode layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 8, the lower electrode layer 103 is patterned by a lift-off method or an etching method. As a result, the groove portion 124 is formed in the lower electrode layer 103.
　図９は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、下側基部に凹部が形成された状態を示す図である。図９に示すように、下側基部１１１の下面側から下側基部１１１に対して深掘反応性イオンエッチング（Ｄｅｅｐ　ＲＩＥ：Deep　Reactive　Ion　Etching）をすることにより、下側基部１１１において凹部１３０が形成される。 FIG. 9 is a diagram showing a state in which a concave portion is formed in the lower base portion in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 9, by performing deep reactive ion etching (Deep RIE: Deep Reactive Ion Etching) from the lower surface side of the lower base 111 to the lower base 111, the recess 130 is formed in the lower base 111. It is formed.
　さらに、上側基部１１２の下側面から上側基部１１２に対して深掘反応性イオンエッチングをすることにより、上側基部１１２において凹部１３０が形成される。これらの工程により、本実施形態におけるメンブレン部１２０が形成され、図２に示すような本発明の実施形態１に係る圧電トランスデューサ１００が製造される。 Further, the recess 130 is formed in the upper base 112 by performing deep reactive ion etching on the upper base 112 from the lower surface of the upper base 112. Through these steps, the membrane part 120 in the present embodiment is formed, and the piezoelectric transducer 100 according to the first embodiment of the present invention as shown in FIG. 2 is manufactured.
　ここで、本実施形態に係る圧電トランスデューサ１００の駆動時の動作について説明する。本実施形態に係る圧電トランスデューサ１００が音波または超音波を発生する際は、上部電極パッド１０２ｙと露出した下部電極層１０３との間に電圧が印加される。そして、上部配線層１０２ｘおよび下部電極層１０３の各々を通じて、板状部１２１において上部電極層１０２と下部電極層１０３とに挟まれて位置する圧電体層１０１に電圧が印加される。これにより、上部電極層１０２、下部電極層１０３および活性層１０４に拘束された圧電体層１０１に歪みが生ずるため、メンブレン部１２０が上下方向に屈曲振動する。これにより、音波または超音波が発生する。 Here, the operation of the piezoelectric transducer 100 according to the present embodiment during driving will be described. When the piezoelectric transducer 100 according to the present embodiment generates a sound wave or an ultrasonic wave, a voltage is applied between the upper electrode pad 102y and the exposed lower electrode layer 103. Then, a voltage is applied to the piezoelectric layer 101 located between the upper electrode layer 102 and the lower electrode layer 103 in the plate-shaped portion 121 through each of the upper wiring layer 102x and the lower electrode layer 103. As a result, the piezoelectric layer 101 constrained by the upper electrode layer 102, the lower electrode layer 103, and the active layer 104 is distorted, so that the membrane portion 120 flexurally vibrates vertically. As a result, sound waves or ultrasonic waves are generated.
　本実施形態に係る圧電トランスデューサ１００が音波または超音波を検出する際は、音波または超音波によりメンブレン部１２０が屈曲振動することによって圧電体層１０１が歪み、このとき圧電体層１０１に作用した応力によって圧電体層１０１の内部において電荷が誘起される。これにより、上部電極層１０２と下部電極層１０３との間に生じた電位差が、上部電極パッド１０２ｙおよび露出した下部電極層１０３から検出される。このように、音波または超音波を圧電トランスデューサ１００によって検出することができる。 When the piezoelectric transducer 100 according to the present embodiment detects a sound wave or an ultrasonic wave, the piezoelectric layer 101 is distorted due to bending vibration of the membrane portion 120 due to the sound wave or the ultrasonic wave, and the stress acting on the piezoelectric layer 101 at this time. Electric charges are thereby induced inside the piezoelectric layer 101. Thereby, the potential difference generated between the upper electrode layer 102 and the lower electrode layer 103 is detected from the upper electrode pad 102y and the exposed lower electrode layer 103. In this way, acoustic waves or ultrasonic waves can be detected by the piezoelectric transducer 100.
　本実施形態に係る圧電トランスデューサ１００においては、接続部１２３に複数の溝部１２４が形成されていることにより、メンブレン部１２０に生じた残留応力を緩和することができる、具体的には、板状部１２１に生じた残留応力が、接続部１２３を通じて基端部１２２および基部１１０に負荷されることを抑制することができる。 In the piezoelectric transducer 100 according to the present embodiment, the plurality of groove portions 124 are formed in the connection portion 123, so that the residual stress generated in the membrane portion 120 can be relaxed, specifically, the plate portion. It is possible to prevent the residual stress generated in 121 from being applied to the base end portion 122 and the base portion 110 through the connection portion 123.
　以下、本実施形態に係る圧電トランスデューサ１００における応力緩和のメカニズムについて、実施例および比較例に基づいて説明する。 Hereinafter, the mechanism of stress relaxation in the piezoelectric transducer 100 according to the present embodiment will be described based on examples and comparative examples.
　図１０は、比較例に係る圧電トランスデューサのメンブレン部の一部を示す平面図である。図１０に示すように、比較例に係る圧電トランスデューサ９００の接続部９２３は、第１接続領域９２１Ｒから板状部９２１の外周側に延在して第２接続領域９２２Ｒを通過する仮想直線Ｌ上において連続している形状を有している。具体的には、接続部９２３の一部は、板状部９２１の径方向に直線状に延在して、板状部９２１の第１接続領域９２１Ｒと基端部９２２の第２接続領域９２２Ｒとを互いに接続している。 FIG. 10 is a plan view showing a part of the membrane portion of the piezoelectric transducer according to the comparative example. As shown in FIG. 10, the connection portion 923 of the piezoelectric transducer 900 according to the comparative example extends on the virtual straight line L extending from the first connection region 921R to the outer peripheral side of the plate-shaped portion 921 and passing through the second connection region 922R. Has a continuous shape. Specifically, a part of the connection portion 923 linearly extends in the radial direction of the plate-shaped portion 921, and the first connection region 921R of the plate-shaped portion 921 and the second connection region 922R of the base end portion 922 are formed. And are connected to each other.
　比較例に係る圧電トランスデューサ９００においては、板状部９２１に生じた残留応力Ｓが、第１接続領域９２１Ｒから、直線状に延在している接続部９２３の一部を通じて第２接続領域９２２Ｒに作用する。そのため、メンブレン部に設けられている溝部９２４によって残留応力Ｓを十分に緩和することができず、残留応力Ｓによって、メンブレン部に撓みが生ずる、または、メンブレン部が外周側に引っ張られる。 In the piezoelectric transducer 900 according to the comparative example, the residual stress S generated in the plate-shaped portion 921 is transferred from the first connection region 921R to the second connection region 922R through a part of the connection portion 923 that extends linearly. To work. Therefore, the residual stress S cannot be sufficiently relaxed by the groove portion 924 provided in the membrane portion, and the residual stress S causes the membrane portion to bend or the membrane portion to be pulled toward the outer peripheral side.
　図１１は、実施例に係る圧電トランスデューサのメンブレン部の一部を示す平面図である。図１１に示すように、実施例に係る圧電トランスデューサ１００ｅの接続部１２３においては、第１接続領域１２１Ｒから板状部１２１の外周側に延在して第２接続領域１２２Ｒを通過する全ての仮想直線Ｌ上に、少なくとも１つの溝部１２４が配置されている。すなわち、全ての仮想直線Ｌは、少なくとも１つの溝部１２４と交差している。これにより、接続部１２３には、第１接続領域１２１Ｒと第２接続領域１２２Ｒとを直線的に接続する部分が存在しない。 FIG. 11 is a plan view showing a part of the membrane portion of the piezoelectric transducer according to the example. As shown in FIG. 11, in the connecting portion 123 of the piezoelectric transducer 100e according to the example, all the virtual portions extending from the first connecting region 121R to the outer peripheral side of the plate-like portion 121 and passing through the second connecting region 122R. At least one groove portion 124 is arranged on the straight line L. That is, all the virtual straight lines L intersect at least one groove portion 124. Therefore, the connecting portion 123 does not have a portion that linearly connects the first connecting region 121R and the second connecting region 122R.
　実施例に係る圧電トランスデューサ１００ｅにおいては、板状部１２１に生じた残留応力Ｓが、第１接続領域１２１Ｒから、溝部１２４を迂回して第２接続領域１２２Ｒに作用する。図１１に示すように、板状部１２１に生じた残留応力Ｓが、第１接続領域１２１Ｒから第２接続領域１２２Ｒに作用する際、接続部１２３における溝部１２４周辺の部分が変形する。接続部１２３における溝部１２４周辺の部分の変形によって、第２接続領域１２２Ｒに作用する残留応力Ｓが低減される。 In the piezoelectric transducer 100e according to the example, the residual stress S generated in the plate-shaped portion 121 acts on the second connection region 122R, bypassing the groove portion 124, from the first connection region 121R. As shown in FIG. 11, when the residual stress S generated in the plate-shaped portion 121 acts on the first connection region 121R to the second connection region 122R, the portion of the connection portion 123 around the groove portion 124 is deformed. The residual stress S acting on the second connection region 122R is reduced by the deformation of the portion around the groove portion 124 in the connection portion 123.
　このように、実施例に係る圧電トランスデューサ１００ｅにおいては、第１接続領域１２１Ｒから第２接続領域１２２Ｒまでの残留応力Ｓが伝達される経路を長くするとともに、接続部１２３における溝部１２４周辺の部分の変形によって残留応力Ｓを低減することにより、残留応力Ｓを十分に緩和することができる。その結果、圧電トランスデューサ１００ｅにおいては、残留応力Ｓによって、メンブレン部に撓みが生ずる、または、メンブレン部が外周側に引っ張られる、ことを抑制することができる。 As described above, in the piezoelectric transducer 100e according to the example, the path through which the residual stress S is transmitted from the first connection region 121R to the second connection region 122R is lengthened, and at the portion around the groove portion 124 in the connection portion 123. By reducing the residual stress S by deformation, the residual stress S can be sufficiently relaxed. As a result, in the piezoelectric transducer 100e, it is possible to prevent the residual stress S from bending the membrane part or pulling the membrane part toward the outer peripheral side.
　よって、圧電トランスデューサ１００ｅの駆動時に、メンブレン部を所望の振動モードで励振させることができるとともに、メンブレン部の上下方向の変位量の低下を抑制することができる。ひいては、圧電トランスデューサ１００ｅの入出力特性の低下を抑制することができる。 Therefore, when the piezoelectric transducer 100e is driven, the membrane part can be excited in a desired vibration mode, and a decrease in the vertical displacement of the membrane part can be suppressed. As a result, it is possible to suppress the deterioration of the input/output characteristics of the piezoelectric transducer 100e.
　上記のように、本実施形態に係る圧電トランスデューサ１００においては、接続部１２３は、複数の第１接続領域１２１Ｒのうちの任意の第１接続領域１２１Ｒから、板状部１２１の外周側に延在して複数の第２接続領域１２２Ｒのうちの任意の第２接続領域１２２Ｒを通過する複数の仮想直線Ｌ上の各々において、メンブレン部１２０に設けられた少なくとも１つの溝部１２４によって不連続となる形状を有している。 As described above, in the piezoelectric transducer 100 according to the present embodiment, the connection portion 123 extends from the arbitrary first connection region 121R of the plurality of first connection regions 121R to the outer peripheral side of the plate-shaped portion 121. Then, on each of a plurality of virtual straight lines L passing through any second connection region 122R among the plurality of second connection regions 122R, a shape that is discontinuous due to at least one groove portion 124 provided in the membrane unit 120 have.
　これにより、上述のようにメンブレン部１２０における残留応力をメンブレン部１２０に設けられている溝部１２４によって緩和することができる。その結果、残留応力の影響による圧電トランスデューサ１００の入出力特性の低下を抑制することができる。 As a result, the residual stress in the membrane portion 120 can be relieved by the groove portion 124 provided in the membrane portion 120 as described above. As a result, it is possible to suppress deterioration of the input/output characteristics of the piezoelectric transducer 100 due to the influence of residual stress.
　本実施形態に係る圧電トランスデューサ１００においては、溝部１２４は、メッシュ状に配置されている。これにより、音波または超音波の発生時、および、音波または超音波の検出時に、メンブレン部１２０が容易に振動するため、圧電トランスデューサ１００の感度を高めることができる。 In the piezoelectric transducer 100 according to this embodiment, the groove portions 124 are arranged in a mesh shape. Accordingly, the membrane portion 120 easily vibrates when a sound wave or an ultrasonic wave is generated and at the time of detecting a sound wave or an ultrasonic wave, so that the sensitivity of the piezoelectric transducer 100 can be increased.
　(実施形態２)
　以下、本発明の実施形態２に係る圧電トランスデューサについて説明する。本発明の実施形態２に係る圧電トランスデューサは、溝部がメンブレン部を上下方向に貫通している点が、圧電トランスデューサ１００と異なる。よって、本発明の実施形態１に係る圧電トランスデューサ１００と同様である構成については説明を繰り返さない。 (Embodiment 2)
The piezoelectric transducer according to the second embodiment of the present invention will be described below. The piezoelectric transducer according to the second embodiment of the present invention is different from the piezoelectric transducer 100 in that the groove portion vertically penetrates the membrane portion. Therefore, the description of the same configuration as the piezoelectric transducer 100 according to the first embodiment of the present invention will not be repeated.
　図１２は、本発明の実施形態２に係る圧電トランスデューサの構成を示す断面図である。図１２に示す圧電トランスデューサ２００の断面図は、図２に示す圧電トランスデューサ１００の断面図と同一の断面視にて図示している。 FIG. 12 is a cross-sectional view showing the configuration of the piezoelectric transducer according to the second embodiment of the present invention. The sectional view of the piezoelectric transducer 200 shown in FIG. 12 is shown in the same sectional view as the sectional view of the piezoelectric transducer 100 shown in FIG.
　図１２に示すように、本実施形態に係る圧電トランスデューサ２００においては、溝部２２４は、メンブレン部２２０を上下方向に貫通している。複数の溝部２２４の各々は、側壁面が圧電体層２０１、下部電極層２０３および活性層２０４で構成されている。 As shown in FIG. 12, in the piezoelectric transducer 200 according to this embodiment, the groove portion 224 penetrates the membrane portion 220 in the vertical direction. The sidewall surface of each of the plurality of groove portions 224 is composed of the piezoelectric layer 201, the lower electrode layer 203, and the active layer 204.
　以下、本発明の実施形態２に係る圧電トランスデューサ２００の製造方法について説明する。 Hereinafter, a method for manufacturing the piezoelectric transducer 200 according to the second embodiment of the present invention will be described.
　図１３は、本発明の実施形態２に係る圧電トランスデューサの製造方法において、下部電極層に溝部を形成した状態を示す図である。図１３に示す下部電極層２０３に溝部２２４を形成する工程までの工程は、図３から図８までに示す本発明の実施形態１に係る圧電トランスデューサ１００の製造方法と同じであるため、説明を繰り返さない。 FIG. 13 is a diagram showing a state in which a groove is formed in the lower electrode layer in the method for manufacturing the piezoelectric transducer according to the second embodiment of the present invention. Since the steps up to the step of forming the groove portion 224 in the lower electrode layer 203 shown in FIG. 13 are the same as the method for manufacturing the piezoelectric transducer 100 according to Embodiment 1 of the present invention shown in FIGS. Do not repeat.
　図１４は、本発明の実施形態２に係る圧電トランスデューサの製造方法において、活性層に溝部を形成した状態を示す図である。図１４に示すように、リフトオフ法またはエッチング法などにより、活性層２０４をパターニングする。これにより、活性層２０４に溝部２２４が形成される。 FIG. 14 is a diagram showing a state in which a groove is formed in the active layer in the method of manufacturing the piezoelectric transducer according to the second embodiment of the present invention. As shown in FIG. 14, the active layer 204 is patterned by a lift-off method or an etching method. As a result, the groove portion 224 is formed in the active layer 204.
　図１５は、本発明の実施形態２に係る圧電トランスデューサの製造方法において、下側基部に凹部が形成された状態を示す図である。図１５に示すように、下側基部１１１の下面側から下側基部１１１に対して深掘反応性イオンエッチングをすることにより、下側基部１１１において凹部２３０が形成される。 FIG. 15 is a diagram showing a state in which a recess is formed in the lower base in the method for manufacturing a piezoelectric transducer according to the second embodiment of the present invention. As shown in FIG. 15, a recess 230 is formed in the lower base 111 by performing deep reactive ion etching on the lower base 111 from the lower surface side of the lower base 111.
　さらに、上側基部１１２の下側面から上側基部１１２に対して深掘反応性イオンエッチングをすることにより、上側基部１１２において凹部２３０が形成される。これらの工程により、本実施形態におけるメンブレン部２２０が形成され、図１２に示すような本発明の実施形態２に係る圧電トランスデューサ２００が製造される。 Further, the recess 230 is formed in the upper base 112 by performing deep reactive ion etching on the upper base 112 from the lower surface of the upper base 112. Through these steps, the membrane part 220 in the present embodiment is formed, and the piezoelectric transducer 200 according to the second embodiment of the present invention as shown in FIG. 12 is manufactured.
　上記のように、本実施形態においては、溝部２２４は、メンブレン部２２０を上下方向に貫通している。これにより、接続部２２３における溝部２２４の周辺部分がより変形しやすくなり、メンブレン部２２０の残留応力をさらに緩和することができる。 As described above, in the present embodiment, the groove portion 224 penetrates the membrane portion 220 in the vertical direction. As a result, the peripheral portion of the groove 224 in the connecting portion 223 is more easily deformed, and the residual stress of the membrane portion 220 can be further alleviated.
　上述した実施形態の説明において、組み合わせ可能な構成を相互に組み合わせてもよい。 In the above description of the embodiments, the configurations that can be combined may be combined with each other.
　今回開示された実施形態はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.
　１００，１００ｅ，２００，９００　圧電トランスデューサ、１０１，２０１　圧電体層、１０２　上部電極層、１０２ｘ　上部配線層、１０２ｙ　上部電極パッド、１０３，２０３　下部電極層、１０４，２０４　活性層、１１０　基部、１１１　下側基部、１１２　上側基部、１２０，２２０　メンブレン部、１２１，９２１　板状部、１２１Ｒ，９２１Ｒ　第１接続領域、１２１Ｓ　外周側面、１２２，９２２　基端部、１２２Ｒ，９２２Ｒ　第２接続領域、１２３，２２３，９２３　接続部、１２４，２２４，９２４　溝部、１３０，２３０　凹部、Ｌ　仮想直線、Ｓ　残留応力。 100, 100e, 200, 900 piezoelectric transducer, 101, 201 piezoelectric layer, 102 upper electrode layer, 102x upper wiring layer, 102y upper electrode pad, 103, 203 lower electrode layer, 104, 204 active layer, 110 base, 111 lower Side base portion, 112 upper base portion, 120, 220 membrane portion, 121, 921 plate portion, 121R, 921R first connection area, 121S outer peripheral side surface, 122, 922 base end portion, 122R, 922R second connection area, 123, 223 , 923 connection part, 124, 224, 924 groove part, 130, 230 recessed part, L virtual straight line, S residual stress.

Claims (3)

  1. 　基部と、
    　前記基部に間接的に支持され、前記基部より上側に位置するメンブレン部とを備え、
    　前記メンブレン部は、前記基部に重なっておらず、かつ、
    　上下方向から見たときに、外周側面を有する板状部と、
    　上下方向から見たときに、前記板状部の外周側に位置して、前記板状部と同心円状の円環状の外形を有する基端部と、
    　前記板状部と前記基端部とを互いに接続する接続部とを含み、
    　前記板状部は、圧電体層と、該圧電体層の上側に配置された上部電極層と、前記圧電体層を挟んで前記上部電極層の少なくとも一部に対向するように配置された下部電極層とを有し、
    　前記板状部は、前記接続部と上下方向の厚さ全体に亘って接続されている複数の第１接続領域を有し、
    　前記複数の第１接続領域は、前記板状部の前記外周側面の周方向に沿って互いに間隔をあけて位置しており、
    　前記基端部は、前記接続部と上下方向の厚さ全体に亘って接続されている複数の第２接続領域を有し、
    　前記複数の第２接続領域は、前記周方向に沿って互いに間隔をあけて位置しており、
    　前記接続部は、前記複数の第１接続領域のうちの任意の第１接続領域から、前記板状部の外周側に延在して前記複数の第２接続領域のうちの任意の第２接続領域を通過する複数の仮想直線上の各々において、前記メンブレン部に設けられた少なくとも１つの溝部によって不連続となる形状を有している、圧電トランスデューサ。     The base,
    Indirectly supported by the base, comprising a membrane portion located above the base,
    The membrane portion does not overlap the base portion, and,
    When viewed from above and below, a plate-shaped portion having an outer peripheral side surface,
    When viewed from the up-down direction, located on the outer peripheral side of the plate-shaped portion, a base end portion having an annular outer shape concentric with the plate-shaped portion,
    Including a connecting portion that connects the plate-shaped portion and the base end portion to each other,
    The plate-shaped portion includes a piezoelectric layer, an upper electrode layer disposed above the piezoelectric layer, and a lower portion disposed so as to face at least a part of the upper electrode layer with the piezoelectric layer interposed therebetween. And an electrode layer,
    The plate-shaped portion has a plurality of first connection regions connected to the connection portion over the entire thickness in the vertical direction,
    The plurality of first connection regions are located at intervals along the circumferential direction of the outer peripheral side surface of the plate-shaped portion,
    The base end portion has a plurality of second connection regions connected to the connection portion over the entire thickness in the vertical direction,
    The plurality of second connection regions are spaced from each other along the circumferential direction,
    The connection portion extends from an arbitrary first connection area of the plurality of first connection areas to an outer peripheral side of the plate-shaped portion and an arbitrary second connection of the plurality of second connection areas. A piezoelectric transducer having a shape that is discontinuous due to at least one groove portion provided in the membrane portion on each of a plurality of virtual straight lines passing through the region.
  2. 　前記溝部は、メッシュ状に配置されている、請求項１に記載の圧電トランスデューサ。 The piezoelectric transducer according to claim 1, wherein the groove portions are arranged in a mesh shape.
  3. 　前記溝部は、前記メンブレン部を上下方向に貫通している、請求項１または請求項２に記載の圧電トランスデューサ。 The piezoelectric transducer according to claim 1 or 2, wherein the groove portion vertically penetrates the membrane portion.
PCT/JP2019/032101 2018-12-19 2019-08-16 Piezoelectric transducer WO2020129296A1 (en)

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JPS63316999A (en) * 1987-06-19 1988-12-26 Tokin Corp Piezoelectric buzzer

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JP4632853B2 (en) 2005-05-13 2011-02-16 オリンパスメディカルシステムズ株式会社 Capacitive ultrasonic transducer and manufacturing method thereof
JP4800170B2 (en) * 2006-10-05 2011-10-26 株式会社日立製作所 Ultrasonic transducer and manufacturing method thereof
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