JP2017069662A - Piezoelectric element substrate, piezoelectric module, ultrasonic module and ultrasonic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric element substrate capable of being reduced in size, and a piezoelectric module, an ultrasonic probe and an ultrasonic device.SOLUTION: An ultrasonic device comprises: an element substrate 41 having a back surface 41A and an operating surface 41B and being disposed with a plurality of opening portions 41C in an array; and a plurality of piezoelectric elements 413 provided at an operating surface 41B side of the element substrate 41. Any ones of the plurality of opening portions 41C are through holes 41C2, and the other opening portions 41C are recessed grooves 41C1. The plurality of piezoelectric elements 413 are provided at the operating surface 41B side in groove bottom surfaces of the recessed grooves 41C1. Through electrodes 41D passing through from the operating surface 41B to the back surface 41A of the element substrate 41 and being electrically connected to the piezoelectric elements 413 at the operating surface 41B side are provided on the through holes 41C2.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a piezoelectric element substrate, a piezoelectric module, an ultrasonic module, and an ultrasonic device.

  2. Description of the Related Art Conventionally, an ultrasonic transducer that performs ultrasonic transmission / reception processing and the like is known (see, for example, Patent Document 1). The ultrasonic transducer described in Patent Document 1 includes a piezoelectric element in which a support film covering an opening is provided on an element substrate having an opening, and a lower electrode, a piezoelectric film, and an upper electrode are stacked on the support film. Have an array structure arranged in an array. Such an ultrasonic transducer can be made thinner than an ultrasonic device using a bulk-type vibrator.

JP 2014-209728 A

By the way, in the ultrasonic transducer described in Patent Document 1, when the element substrate and the wiring substrate are connected, a terminal portion connected to a signal line drawn from each piezoelectric element is provided outside the array region of the element substrate. For example, it is necessary to connect the terminal portion and the wiring board via an FPC or the like. For this reason, a space for providing a plurality of terminal portions outside the array region of the piezoelectric elements is necessary, and there is a problem that the substrate size becomes large.
On the other hand, a configuration is also conceivable in which a through electrode is provided between the openings in the element substrate so as to be electrically connected to the lower electrode and the upper electrode and connected to the wiring substrate through the through electrode. However, in this case, in order to arrange the through electrodes, it is necessary to provide a large space between the openings (between the piezoelectric elements), and the substrate size cannot be sufficiently reduced. Moreover, there exists a subject that an ultrasonic characteristic falls by the dimension between piezoelectric elements becoming large.

  An object of the present invention is to provide a piezoelectric element substrate, a piezoelectric module, an ultrasonic module, and an ultrasonic device that can be miniaturized.

  A piezoelectric element substrate according to an application example of the present invention has a first surface and a second surface opposite to the first surface, and a plurality of openings in which the second surface side opens in a predetermined array region. And a plurality of piezoelectric elements provided on the first surface side of the element substrate, and any one of the plurality of openings includes the element substrate as a substrate. It is a through-hole penetrating in the thickness direction, the other opening is a concave groove, the piezoelectric element is provided on the first surface side of the groove bottom surface of the concave groove, and the element substrate includes the element substrate A through-electrode that penetrates from the first surface to the second surface and is electrically connected to the piezoelectric element on the first surface side is provided.

In this application example, the element substrate is provided with a plurality of openings in an array. The opening includes a groove having a piezoelectric element provided on the groove bottom surface and a through hole penetrating the element substrate from the first surface to the second surface. A through electrode is provided in the through hole, and the through electrode is electrically connected to a piezoelectric element provided on the first surface side of the groove on the first surface side.
In such a configuration, for example, a piezoelectric element substrate is placed on a wiring board or the like, and a terminal portion provided on the wiring board or the like is brought into contact with the through electrode, so that a signal can be easily transmitted to each piezoelectric element. I / O can be performed. Therefore, for example, the planar size of the piezoelectric element substrate can be reduced as compared with the case where a plurality of lead lines are drawn out from the piezoelectric element to form terminal portions and these terminal portions are connected to a wiring substrate or the like by FPC or the like. . In addition, in the case where a through electrode that is electrically connected to the piezoelectric element is provided between the openings (that is, between the piezoelectric elements), it is necessary to secure a space for arranging the through electrode between the openings. The planar size of the substrate is increased. In contrast, in this application example, any one of the plurality of openings arranged in an array is used as a through hole, and a through electrode is provided in the through hole. For this reason, it is not necessary to widen the space | interval between opening parts, and the enlargement of the plane size of a piezoelectric element board | substrate by this does not occur.
As described above, in this application example, the planar size of the piezoelectric element substrate can be reduced as compared with the conventional example.

In the piezoelectric element substrate of this application example, it is preferable that the through hole is provided at a position that is point-symmetric with respect to the center of the array region.
When a piezoelectric element is disposed on the bottom surface of a groove as a piezoelectric element substrate, for example, when a thin film-like piezoelectric element is driven to drive the bottom surface of the groove or displacement of the bottom surface of the groove is detected by the piezoelectric element, the piezoelectric element It is necessary to reduce the thickness dimension of the substrate. In such a piezoelectric element substrate, if through holes are provided in one place in the array region (for example, at positions adjacent to each other in the front, rear, left, and right directions), the substrate strength in the vicinity of the through holes decreases, and the stress balance in the substrate is reduced. It becomes non-uniform. For example, when the through holes are concentrated and arranged on one end side of the array region, the substrate strength on one end side in the array region becomes weak. In this case, the substrate may be easily damaged at one end side of the array region in which the through holes are arranged and the ultrasonic characteristics may be non-uniform due to non-uniform stress balance.
On the other hand, in this application example, the through hole is provided so as to be point-symmetric with respect to the center of the array region. With such a configuration, the stress balance of the substrate becomes uniform, and a decrease in substrate strength and a deterioration in ultrasonic characteristics can be suppressed.

In the piezoelectric element substrate of this application example, it is preferable that the opening adjacent to the through hole is the concave groove.
In this application example, the through holes are not arranged adjacent to each other in the openings arranged in an array. For this reason, it is possible to suppress a decrease in the strength of the substrate as in the above application example.

In the piezoelectric element substrate of this application example, the piezoelectric element is configured by a stacked body in which a first electrode layer, a piezoelectric film, and a second electrode layer are stacked from the groove bottom surface side of the concave groove, It is preferable to be connected to the first electrode layer.
In this application example, the piezoelectric element is configured by laminating the first electrode layer, the piezoelectric film, and the second electrode layer on the groove bottom surface in this order, and the first electrode layer is connected to the through electrode. ing. Since the first electrode layer is provided on the groove bottom surface of the concave groove or at a position closest to the groove bottom surface of the piezoelectric element, it can be easily connected to the through electrode.

In the piezoelectric element substrate of this application example, the openings are arranged in an array along the first direction and the second direction intersecting the first direction, and are arranged along the first direction. One piezoelectric element group is constituted by the piezoelectric elements, and a plurality of the piezoelectric element groups are arranged along the second direction in the array region, and the first of the piezoelectric elements belonging to the same piezoelectric element group is arranged. The electrode layers are electrically connected to each other, and at least one of the plurality of openings disposed along the first direction is preferably the through hole.
In this application example, one piezoelectric element group is configured by the piezoelectric elements arranged along the first direction, and a plurality of the piezoelectric element groups are arranged along the second direction. The first electrode layers of the piezoelectric elements belonging to one piezoelectric element group are electrically connected to each other, and the second electrode layers of the piezoelectric elements belonging to one piezoelectric element group are electrically connected. And the 1st electrode layer of the same piezoelectric element group is connected to the penetration electrode of the through-hole provided along the 1st direction where the said piezoelectric element group is arrange | positioned.
In such a configuration, for example, a common potential (COM signal) is applied to the second electrode layer of the same piezoelectric element group, and a desired drive potential (SIG signal) is applied to the first electrode layer. Thus, the piezoelectric elements belonging to the same piezoelectric element group can be driven simultaneously. That is, a plurality of piezoelectric elements arranged in the array region can be driven as a one-dimensional array with the piezoelectric element group as one channel (channel).
At this time, as in this application example, one of the openings arranged along the first direction in which the piezoelectric element group is arranged is a through hole provided with a through electrode for applying a driving potential. Since the distance from the through electrode to each piezoelectric element can be shortened and the electric resistance is also reduced, the voltage drop of the drive voltage applied to each piezoelectric element can be suppressed.

In the piezoelectric element substrate of this application example, the through hole is formed in at least one of two diagonal lines of the rectangular array region surrounded by two sides along the first direction and two sides along the second direction. It is preferable that it is provided along.
In this application example, as described above, one piezoelectric element group is driven as one channel (channel) to output ultrasonic waves, and the ultrasonic waves output from the plurality of piezoelectric element groups arranged along the second direction. By superimposing these wavefronts, an ultrasonic beam can be output in a predetermined direction. When forming such an ultrasonic beam, it is preferable to transmit ultrasonic waves having the same output from each piezoelectric element belonging to each piezoelectric element group. However, in practice, as the distance from the position where the through electrode (through hole) is provided, the drive voltage input to the piezoelectric element decreases (voltage drop), and accordingly, the ultrasonic wave transmitted from each piezoelectric element. There is a bias in the intensity (the intensity distribution is non-uniform).
Here, ultrasonic waves output from a group of piezoelectric elements that are far away (for example, a group of piezoelectric elements arranged at both ends in the second direction) do not have a great effect even if their intensity distributions are different from each other. . On the other hand, if there is a large difference in intensity distribution between ultrasonic waves transmitted from adjacent piezoelectric element groups, it is difficult to superimpose the wavefronts of the ultrasonic waves, and as a result, an accurate ultrasonic beam cannot be formed.
On the other hand, in this application example, the through holes are provided along two diagonal lines in the rectangular array region. Therefore, in the adjacent piezoelectric element groups, the bias of the voltage drop is substantially the same. In this case, for example, even when ultrasonic waves are transmitted from each piezoelectric element group to form an ultrasonic beam, the intensity distribution of ultrasonic waves transmitted from adjacent piezoelectric element groups becomes substantially the same distribution. Therefore, it is possible to suitably superimpose the wavefronts of ultrasonic waves, and it is possible to form an ultrasonic beam with high accuracy.

In the piezoelectric element substrate of this application example, the through holes are provided at positions that pass through the center of the piezoelectric element group along the first direction and are symmetrical with respect to a virtual line along the second direction. It is preferable.
In this application example, the through holes are provided at positions that are line-symmetric with respect to the virtual line in the first direction. For this reason, the voltage drop in one piezoelectric element group can be suppressed as much as possible. That is, in the piezoelectric element group, the piezoelectric element at a position far from the position where the through electrode is provided is greatly affected by the voltage drop as compared with the piezoelectric element in the vicinity of the through electrode. Therefore, for example, when the through electrode is provided only at one end in the first direction, the voltage drop of the piezoelectric element provided at the other end increases. On the other hand, in this application example, the through holes are provided at positions that are line-symmetric with respect to a virtual line that passes through the center along the first direction and is parallel to the second direction. Therefore, for example, when the first through hole is provided at one end in the first direction, the second through hole is provided at the other end in the first direction. In this case, since the drive potential (SIG signal) is applied to the first electrode layer from these through holes, the influence of the voltage drop can be suppressed.
Furthermore, as described above, in the configuration in which the through holes are provided along the diagonal lines of the array region, the through holes are provided along both of the two diagonal lines. For this reason, the stress balance in the piezoelectric element substrate can be made more uniform.

In the piezoelectric element substrate according to this application example, the openings are arranged in an array along a first direction and a second direction intersecting the first direction, and the array region includes a plurality of partial array regions. In each partial array region, n × m openings, which are composed of n pieces along the first direction and m pieces along the second direction, are arranged in an array. The through-hole is preferably provided at a position that is point-symmetric with respect to the center of the partial array region.
In this application example, the piezoelectric element group can be configured by each piezoelectric element provided in the partial array region provided in the n × m openings. Even in such a configuration, the stress balance of the piezoelectric element substrate can be made uniform by arranging the through holes in each partial array so as to be point-symmetric with respect to the center of the partial array.

The piezoelectric module of one application example according to the present invention has a first surface and a second surface opposite to the first surface, and a plurality of openings that open on the second surface side in a predetermined array region. Are arranged in an array, and a plurality of piezoelectric elements provided on the first surface side of the element substrate, and a back surface bonded to the second surface of the element substrate A substrate and a wiring substrate, and any one of the plurality of openings is a through-hole penetrating the element substrate in the substrate thickness direction, the other openings are concave grooves, and the piezoelectric element is , Provided on the first surface side of the groove bottom surface of the concave groove, the through hole penetrating from the first surface to the second surface of the element substrate, and the piezoelectric element on the first surface side A through electrode electrically connected to the back substrate is provided. A second through electrode electrically connected to the through electrode and penetrating in a substrate thickness direction, and the wiring board is provided at a position corresponding to each of the second through electrode, It is preferable that the terminal part connected electrically is provided.
In this application example, similarly to the above application example, the piezoelectric element substrate can be reduced in size, so that the piezoelectric module can also be reduced in size.

An ultrasonic module according to an application example of the present invention has a first surface and a second surface opposite to the first surface, and a plurality of openings in which the second surface side opens in a predetermined array region. A piezoelectric element substrate having element portions arranged in an array and a plurality of piezoelectric elements provided on the first surface side of the element substrate; and bonded to the second surface of the element substrate A back substrate and a wiring substrate, and any one of the plurality of openings is a through-hole penetrating the element substrate in a substrate thickness direction, and the other opening is a concave groove, and the piezoelectric element Is provided on the first surface side of the groove bottom surface of the concave groove, and the through hole penetrates from the first surface to the second surface of the element substrate, and the piezoelectric surface on the first surface side. A through electrode electrically connected to the element is provided, and the back substrate is A second through electrode that is electrically connected to the through electrode and penetrates in the thickness direction of the substrate; and the wiring board is provided at a position corresponding to each of the second through electrode, Connected to the terminal unit, ultrasonic transmission processing for outputting a drive signal to the piezoelectric element and outputting an ultrasonic wave, and detection input from the piezoelectric element And a drive circuit that performs at least one of ultrasonic reception processing for detecting ultrasonic waves based on the signal.
In this application example, as in the above application example, the piezoelectric element substrate can be reduced in size, so that the ultrasonic module can also be reduced in size.

An ultrasonic apparatus according to an application example of the present invention has a first surface and a second surface opposite to the first surface, and a plurality of openings in which the second surface side opens in a predetermined array region. A piezoelectric element substrate having element portions arranged in an array and a plurality of piezoelectric elements provided on the first surface side of the element substrate; and bonded to the second surface of the element substrate A back substrate, a wiring substrate, and a control unit, wherein one of the plurality of openings is a through-hole penetrating the element substrate in the substrate thickness direction, and the other opening is a groove. The piezoelectric element is provided on the first surface side of the groove bottom surface of the concave groove, and the through hole penetrates from the first surface to the second surface of the element substrate. On the side, a through electrode electrically connected to the piezoelectric element is provided, and the back substrate is A second through electrode electrically connected to the through electrode and penetrating in a substrate thickness direction, and the wiring board is provided at a position corresponding to each of the second through electrode; An electrically connected terminal part, an ultrasonic transmission process for outputting a drive signal to the piezoelectric element and outputting an ultrasonic wave electrically connected to the terminal part, and input from the piezoelectric element A drive circuit that performs at least one of ultrasonic reception processes for detecting an ultrasonic wave based on a detection signal, and the control unit uses the drive circuit and the plurality of piezoelectric elements to perform the ultrasonic wave It controls at least one of the transmission process and the ultrasonic wave reception process.
In this application example, as in the above application example, the piezoelectric element substrate and the ultrasonic module can be reduced in size, so that the ultrasonic apparatus including the ultrasonic module can also be reduced in size.

The perspective view which shows schematic structure of the ultrasonic measuring device of 1st embodiment. 1 is a block diagram showing a schematic configuration of an ultrasonic measurement apparatus according to a first embodiment. The top view which shows schematic structure of the ultrasonic sensor in 1st embodiment. The top view which looked at the element substrate in the ultrasonic device of a first embodiment from the sealing board side. The enlarged plan view which expanded a part in the array area | region in FIG. Sectional drawing of the ultrasonic sensor cut | disconnected by the AA line in FIG. Sectional drawing of the ultrasonic sensor cut | disconnected by the BB line in FIG. Schematic which shows the arrangement configuration of the opening part of 1st embodiment. The figure which shows the manufacturing method of the ultrasonic device of 1st embodiment. The figure which shows the manufacturing method of the ultrasonic device of 1st embodiment. Schematic which shows the arrangement configuration of the opening part of 2nd embodiment. Schematic which shows the arrangement structure of the opening part of 3rd embodiment. The figure which shows the manufacturing method of the ultrasonic device in other embodiment. Schematic which shows the arrangement configuration of the opening part in other embodiment. The figure which shows schematic structure of the ultrasonic cleaner which is an electronic device of other embodiment.

[First embodiment]
Hereinafter, an ultrasonic measurement device as an electronic apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
[Configuration of Ultrasonic Measuring Apparatus 1]
FIG. 1 is a perspective view showing a schematic configuration of an ultrasonic measurement apparatus 1 of the present embodiment. FIG. 2 is a block diagram showing a schematic configuration of the ultrasonic measurement apparatus 1.
The ultrasonic measurement apparatus 1 of the present embodiment corresponds to the ultrasonic apparatus in the present invention, and is electrically connected to the ultrasonic probe 2 and the ultrasonic probe 2 via a cable 3 as shown in FIG. And a control device 10.
The ultrasonic measurement apparatus 1 causes an ultrasonic probe 2 to abut on the surface of a living body (for example, a human body), and transmits ultrasonic waves from the ultrasonic probe 2 into the living body. In addition, the ultrasonic wave reflected by the organ in the living body is received by the ultrasonic probe 2, and based on the received signal, for example, an internal tomographic image in the living body is obtained, or the state of the organ in the living body (for example, Blood flow etc.).

[Configuration of Ultrasonic Probe 2]
FIG. 3 is a plan view showing a schematic configuration of the ultrasonic sensor 24 in the ultrasonic probe 2.
The ultrasonic probe 2 includes a housing 21, an ultrasonic device 22 provided inside the housing 21, and a wiring board 23 provided with a driver circuit and the like for controlling the ultrasonic device 22. . Note that an ultrasonic sensor 24 is constituted by the ultrasonic device 22 and the wiring board 23, and the ultrasonic sensor 24 constitutes a piezoelectric module or an ultrasonic module of the present invention.

As shown in FIG. 1, the housing 21 is formed, for example, in a box shape having a rectangular shape in plan view, and a sensor window 21 </ b> B is provided on one surface (sensor surface 21 </ b> A) orthogonal to the thickness direction. A part of is exposed. Further, a passage hole 21C of the cable 3 is provided in a part (side surface in the example shown in FIG. 1) of the housing 21, and the cable 3 is connected to the wiring board 23 inside the housing 21 through the passage hole 21C. ing. Further, the gap between the cable 3 and the passage hole 21 </ b> C is ensured to be waterproof, for example, by being filled with a resin material or the like.
In the present embodiment, a configuration example in which the ultrasonic probe 2 and the control device 10 are connected using the cable 3 is shown, but the present invention is not limited to this. For example, the ultrasonic probe 2 and the control device 10 are wirelessly connected. They may be connected by communication, and various configurations of the control device 10 may be provided in the ultrasonic probe 2.

[Configuration of Ultrasonic Device 22]
FIG. 4 is a plan view of the element substrate 41 in the ultrasonic device 22 as viewed from the side opposite to the sealing plate 42 (operation surface side). FIG. 5 is an enlarged plan view in which a part of the array region Ar1 in FIG. 4 is enlarged. 6 is a cross-sectional view of the ultrasonic sensor 24 taken along the line AA in FIG. FIG. 7 is a cross-sectional view of the ultrasonic sensor 24 taken along line BB in FIG.
As shown in FIGS. 6 and 7, the ultrasonic device 22 constituting the ultrasonic sensor 24 includes an element substrate 41, a sealing plate 42 (back substrate), an acoustic matching layer 43, and an acoustic lens 44 (FIG. 1). Reference).

(Configuration of element substrate 41)
As shown in FIGS. 6 and 7, the element substrate 41 includes a substrate body 411, a vibration film 412 stacked on the substrate body 411, and a piezoelectric element 413 stacked on the vibration film 412.
Here, the element substrate 41 including the substrate body 411 and the vibration film 412 and the piezoelectric element 413 constitute the piezoelectric element substrate of the present invention. In the element substrate 41, the back surface 41A facing the sealing plate 42 is the second surface in the present invention, and the operation surface 41B opposite to the back surface 41A is the first surface in the present invention.
As shown in FIG. 4, in a plan view of the element substrate 41 as viewed from the thickness direction, an ultrasonic element array 50 in which a plurality of ultrasonic elements 51 are arranged in an array is formed in the central region of the element substrate 41. Is provided. Hereinafter, the region in which the ultrasonic element array 50 is provided is referred to as an array region Ar1.

In the array region Ar1 of the element substrate 41, a plurality of openings 41C arranged in an array are provided along the X direction (first direction) and the Y direction (second direction) orthogonal to the X direction. ing. As shown in FIGS. 4 to 7, the opening 41 </ b> C includes a concave groove 41 </ b> C <b> 1 and a through hole 41 </ b> C <b> 2. The concave groove 41C1 includes a hole 411A (see FIGS. 6 and 7) that penetrates the substrate main body 411 in the thickness direction, and a vibration film 412 that closes the operating surface 41B side of the hole 411A. The through-hole 41C2 is provided in a hole 411A that penetrates the substrate body 411 in the thickness direction and a part of the vibration film 412 provided on the operating surface 41B side of the hole 411A. It is comprised by the hole part 412A (refer FIG. 6, 7) penetrated in the direction, and these hole parts 411A and the hole part 412A communicate.
The arrangement of the concave grooves 41C1 and the through holes 41C2 in the array region Ar1 will be described later.

Hereinafter, each part which comprises the element substrate 41 is demonstrated in detail.
The substrate body 411 is a semiconductor substrate such as Si, and is formed in a planar rectangular shape, for example. In the array region Ar1 of the substrate body 411, as described above, a plurality of holes 411A arranged in an array along the X direction and the Y direction are provided. These hole parts 411A penetrate the substrate body part 411 in the thickness direction.
Further, in a plan view of the substrate body 411, a COM hole penetrating the substrate thickness direction is provided at a position corresponding to a diagonal portion of the rectangular corner portion of the element substrate 41 that is diagonally related. Yes.

The vibration film 412 is made of, for example, SiO ₂ , a laminated body of SiO ₂ and ZrO ₂ , and is provided on the operating surface 41B side of the substrate body 411.
The thickness dimension of the vibration film 412 is sufficiently small with respect to the substrate main body 411. When the substrate body 411 is made of Si and the vibration film 412 is made of SiO ₂ , for example, the vibration film 412 having a desired thickness dimension can be easily formed by oxidizing the back surface 41A side of the substrate body 411. It becomes possible.

Further, in a plan view of the vibration film 412 viewed from the thickness direction, the shape of the vibration film 412 differs depending on the position of each region overlapping with the hole 411A of the substrate body 411. That is, as described above, in some of the plurality of regions of the vibration film 412 that overlap with the hole 411A of the substrate body 411, the hole 412A penetrating in the thickness direction is provided. A through hole 41C2 is formed by the hole 412A.
As shown in FIG. 6, the hole portion 412 </ b> A has a shape that is inclined in a tapered shape in which the opening diameter is reduced from the back surface 41 </ b> A side of the vibration membrane 412 toward the working surface 41 </ b> B side.
As shown in FIGS. 5 and 7, the opening dimension “a” of the hole 412A along the X direction on the side of the operating surface 41B is the same as that of the hole 411A.
Further, the opening dimension b on the working surface 41B side of the hole 412A along the Y direction is smaller than the width dimension c along the Y direction of a piezoelectric film 415 (described later) of the piezoelectric element 413, and the hole dimension with respect to the Y direction is a hole. The portion 412A is preferably formed so as to be within the width of the piezoelectric film 415. More preferably, as shown in FIGS. 5 and 6, the opening dimension b on the working surface 41B side of the hole 412A along the Y direction is set to the same dimension as the width dimension d of the lower electrode 414 (described later), and the lower electrode 414 is formed. Is preferably provided so as to overlap.

Of the vibrating membrane 412 that overlaps with the hole 411A, a region where the hole 412A is not provided is a vibrating portion 412B, and the groove 41C1 is formed by the hole 412A and the vibrating portion 412B. Note that the ultrasonic element 51 that transmits and receives ultrasonic waves is configured by the vibration unit 412B and the piezoelectric element 413.
Further, in the vibration film 412, the COM hole portion that penetrates the vibration film 412 in the thickness direction overlaps the COM hole portion of the substrate main body portion 411 at a position corresponding to the diagonal portion of the element substrate 41. The COM through hole 41C3 is formed by these COM holes.

In the present embodiment, a through electrode 41D is provided in the through hole 41C2. For example, the through electrode 41D is filled in the through hole 41C2 and is electrically connected to the lower electrode 414 of the piezoelectric element 413 provided on the operating surface 41B side of the vibration film 412.
Further, the COM through-hole 41C3 (see FIG. 4) is provided in the COM through-hole 41C3 configured by the COM hole provided in the substrate body 411 and the COM hole provided in the vibration film 412. It has been. The COM through electrode 41E is electrically connected to the upper electrode 416 of the piezoelectric element 413.

  As shown in FIGS. 4 and 5, the piezoelectric element 413 is provided in a region overlapping with each opening 41 </ b> C in plan view. As shown in FIGS. 6 and 7, the piezoelectric element 413 has a lower electrode 414 (first electrode layer), a piezoelectric film 415, and an upper electrode 416 (second electrode layer) stacked in order from the vibrating portion 412B side. It is comprised by the laminated body. Among each piezoelectric element 413, a piezoelectric element 413 provided at a position overlapping with the concave groove 41C1 (a piezoelectric element 413 provided on the vibration part 412B) is a rectangular wave having a predetermined frequency between the lower electrode 414 and the upper electrode 416. By applying the voltage, the vibration unit 412B can be vibrated to transmit ultrasonic waves. Further, when the vibration unit 412B is vibrated by the ultrasonic wave reflected from the object, a potential difference is generated above and below the piezoelectric film 415, and the potential difference generated between the lower electrode 414 and the upper electrode 416 is detected. The received ultrasonic wave can be detected.

  On the other hand, among the piezoelectric elements 413, the lower electrode 414 of the piezoelectric element 413 provided at a position overlapping with the through hole 41C2 is in contact with the through electrode 41D provided in the through hole 41C2, as described above, so that electrical Is connected to. Since the through electrode 41D is filled in the through hole 41C2, even if a voltage is applied between the lower electrode 414 and the upper electrode 416 of the piezoelectric element 413 provided at a position overlapping with the through hole 41C2 in a plan view, the piezoelectric element is not piezoelectric. Expansion and contraction of the film 415 is restricted. Therefore, transmission / reception of ultrasonic waves is not performed.

(Arrangement configuration of the opening 41C)
In the present embodiment, as described above, the openings 41C are arranged in a plurality of arrays along the X direction and the Y direction in the array region Ar1 of the element substrate 41. In addition, since the piezoelectric elements 413 are arranged at positions overlapping with the openings 41C, these piezoelectric elements 413 are also arranged in an array along the X direction and the Y direction.
Here, the lower electrode 414 constituting each piezoelectric element 413 is formed in a linear shape along the X direction. That is, the lower electrode 414 is provided across a plurality of piezoelectric elements 413 arranged along the X direction. Specifically, the lower electrode 414 overlaps the lower electrode body 414A positioned between the piezoelectric film 415 and the vibrating portion 412B, the lower electrode wire 414B connecting the adjacent lower electrode bodies 414A, and the through hole 41C2. And an electrode conduction portion 414C that is in contact with the through electrode 41D.
In the present embodiment, one of the openings 41C arranged in the X direction is the through hole 41C2, and the other is the concave groove 41C1. Therefore, in the piezoelectric elements 413 arranged in the X direction, signals are input / output from the through electrode 41D provided in one through hole 41C2.

On the other hand, as shown in FIG. 4, the upper electrode 416 connects the element electrode portions 416A provided across the plurality of piezoelectric elements 413 arranged in the Y direction and the ends of the element electrode portions 416A parallel to each other. Common electrode portion 416B. The element electrode portion 416A includes an upper electrode body 416C laminated on the piezoelectric film 415 and an upper electrode line 416D that connects the adjacent upper electrode bodies 416C.
A part of the common electrode portion 416B corresponding to the diagonal portion of the element substrate 41 is in contact with and connected to the COM through hole 41C3.

Further, as shown in FIG. 7, the inter-element electrode layer 417 is provided on the lower electrode line 414 </ b> B between the openings 41 </ b> C in a cross-sectional view along the X direction. The inter-element electrode layer 417 is an electrode layer formed simultaneously with the patterning of the upper electrode 416 and is insulated from the upper electrode 416. Note that a part of the inter-element electrode layer 417 may be laminated on the piezoelectric film 415 as shown in FIG. In order to suppress conduction between the upper electrode 416 and the inter-electrode layer 417 due to discharge or the like, an insulating layer 418 that covers the inter-electrode layer 417 is preferably provided. As shown in FIGS. 6 and 7, the insulating layer 418 may have one end laminated on the upper electrode 416. For example, the insulating layer 418 covers the inter-element electrode layer 417 and the upper electrode 416 (operation surface of the element substrate 41). It is good also as a structure provided over the 41B side whole.
By providing such an inter-element electrode layer 417, the electrical resistance value between the openings 41C can be reduced, and a voltage drop can be suppressed.

In the ultrasonic element array 50 as described above, one ultrasonic element group 51A (piezoelectric element group) is configured by the ultrasonic elements 51 arranged in the X direction connected by the lower electrode 414, and the ultrasonic element group 51A. Constitutes a one-dimensional array structure in which a plurality of are arranged along the Y direction. In the ultrasonic element array 50 having such a one-dimensional array structure, one ultrasonic element group 51A can be set as 1ch (channel) and can be driven for each channel.
That is, in this embodiment, the COM through electrode 41E connected to the upper electrode 416 is connected to, for example, the common potential circuit 232 (see FIG. 2) provided on the wiring board 23, and a COM signal is applied. Is set to a common potential (for example, 0 potential). That is, in the ultrasonic element array 50, the upper electrode 416 is set to a common potential.
On the other hand, each penetration electrode 41D connected to the lower electrode 414 of each ultrasonic element group 51A is individually connected to a terminal of the wiring board 23. Therefore, a driving potential is applied to the ultrasonic element group 51A based on the SIG signal applied to the lower electrode 414 by driving an individual SIG signal (drive signal) to each through electrode 41D. It is possible to transmit substantially the same ultrasonic wave from each ultrasonic element 51 belonging to one ultrasonic element group 51A. In addition, by delaying the application timing of the SIG signal to each ultrasonic element group 51A, the wavefront of the ultrasonic wave can be directed in a desired direction. Furthermore, when the ultrasonic waves are received, by detecting the reception signals output from the respective ultrasonic element groups 51A, the timing at which the ultrasonic waves are received by the respective ultrasonic element groups 51A can be detected. It becomes possible to specify the reflection position of the ultrasonic wave.

  Here, for example, when the lower electrode 414 connected to each ultrasonic element 51 is pulled out to the outer peripheral portion of the element substrate 41 and the leading end portion is connected to the terminal of the wiring substrate 23, the input of the SIG signal in the lower electrode 414 is performed. The distance between the output position and each ultrasonic element 51 becomes longer. Thus, when the length of the signal line is increased, a voltage drop occurs due to the wiring resistance. In contrast, in the present embodiment, one of the openings 41C arranged in the X direction is the through hole 41C2, and the ultrasonic elements 51 arranged in the X direction from the through electrode 41D provided in the through hole 41C2. The SIG signal is input to. In this case, the through electrode 41D (input / output position of the SIG signal) is close to each ultrasonic element 51, and the influence of the voltage drop can be suppressed. In addition, since it is possible to conduct in the array region Ar1, the size of the element substrate 41 itself can be reduced as compared with the configuration in which the lead region is led out to the outer periphery of the substrate to form the terminal region.

By the way, the array region Ar1 of the element substrate 41 is a region where the array-shaped opening 41C is formed, and the substrate strength against the stress is weak, and, for example, breakage or bending is likely to occur. For this reason, normally, for example, a metal sealing plate 42 is provided on the element substrate 41 to reinforce the element substrate 41. However, in the present embodiment, a part of the opening 41C is the through hole 41C2, and more measures against the substrate strength are required than in the case where all the openings 41C are the concave grooves 41C1.
Here, when the positions where the through holes 41C2 are provided are concentrated in one place, the strength against the stress in the place is further weakened. For example, in the adjacent ultrasonic element group 51A, when the positions of the through holes 41C2 are all at the −X side end, the −X side end in the array region Ar1 has a uniform strength against stress. In such a case, in the region, breakage and deflection are more likely to occur, and the stress balance becomes non-uniform, which may affect the vibration in each vibration part 412B, and high-precision super Cannot output sound waves.
Therefore, the arrangement position of the through hole 41C2 needs to have some variation in the array region Ar1.

However, in the ultrasonic element array 50, when each ultrasonic element group 51A is driven to form an ultrasonic beam, ultrasonic waves are synthesized from adjacent ultrasonic element groups 51A to form a wavefront having a large output value, The wavefront is propagated in a predetermined direction. Therefore, it is preferable that the intensity distribution of the ultrasonic waves output from the adjacent ultrasonic element groups 51A is substantially uniform.
Here, in a certain ultrasonic element group 51A (first ultrasonic element group 51A), when the through hole 41C2 is provided at the −X side end in the X direction, the position is far from the through electrode 41D provided in the through hole 41C2. In the ultrasonic element 51, a slight voltage drop occurs. Therefore, as the ultrasonic wave output from the first ultrasonic element group 51A, a strong ultrasonic wave having no voltage drop is output on the −X side, and on the + X side far from the through electrode 41D, the influence of the voltage drop is output. As a result, an ultrasonic wave having a weaker intensity than that of the −X side is output.
In the second ultrasonic element group 51A adjacent to the first ultrasonic element group 51A as described above, for example, if the through hole 41C2 is provided at the + X side end in the X direction, From the acoustic wave element group 51A, an ultrasonic wave that is weak on the −X side and strong on the + X side is output.
In such a case, since the intensity distribution of the ultrasonic waves output from the adjacent ultrasonic element groups 51A is greatly different, it is difficult to form an accurate ultrasonic beam.

FIG. 8 is a diagram illustrating an arrangement configuration of the concave grooves 41C1 and the through holes 41C2 in the opening 41C in the present embodiment. In FIG. 8, black circles indicate through holes 41C2, and white circles indicate concave grooves 41C1.
In the present embodiment, in order to solve the above two problems, as shown in FIGS. 4 and 8, a through hole 41C2 is arranged.
Specifically, the through hole 41C2 is disposed along one (diagonal line D1) of the diagonal lines D1 and D2 in the rectangular array region Ar1. That is, in the ultrasonic element group 51A arranged at the −Y side end in the Y direction, the through hole 41C2 is arranged at the −X side end, and in the ultrasonic element group 51A adjacent to the + Y side, −X The second opening 41C from the side end becomes the through hole 41C2. In this case, in the adjacent ultrasonic element group 51A, the intensity distribution of the output ultrasonic waves becomes substantially the same, and it is possible to form a highly accurate ultrasonic beam.
Further, the through holes 41C2 are respectively arranged at positions that are point-symmetric with respect to the center point (array center O) of the array region Ar1, and the through holes are located at positions adjacent to the X direction or the Y direction. 41C2 is not lined up. By adopting such a configuration, a region where the substrate strength is weak due to the through hole 41C2 can be dispersed in the array region Ar1, and the stress balance of the element substrate 41 can be made uniform. Therefore, for example, compared to the case where the through hole 41C2 in which the substrate strength is weakened at one place, the substrate can be prevented from being damaged or curved, and highly accurate ultrasonic transmission / reception processing can be performed.

(Configuration of sealing plate 42)
Next, the sealing plate 42 will be described.
As shown in FIG. 6, the sealing plate 42 has a planar shape when viewed from the thickness direction, for example, a rectangular shape, and is configured by a semiconductor substrate such as a silicon substrate or an insulator substrate. In addition, since the material and thickness of the sealing plate 42 affect the frequency characteristics of the ultrasonic element 51, it is preferable to set based on the center frequency of the ultrasonic wave transmitted and received by the ultrasonic element 51.

The sealing plate 42 includes a plurality of through-hole portions 421 corresponding to the openings 41C in a region (see FIGS. 6 and 7) facing the array region Ar1 of the element substrate 41.
And among the through-hole portions 421 provided in the sealing plate 42, the through-electrode 41D penetrating the through-hole 41C2 is inserted into the through-hole portion 421 facing the through-hole 41C2 of the element substrate 41. In the present embodiment, the through electrode 41D provided on the element substrate 41 exemplifies a configuration in which the through hole portion 421 of the sealing plate 42 also penetrates the substrate thickness direction. An electrode that penetrates the through-hole portion 421 of the stop plate 42 may be provided to be electrically connected to the through-electrode 41D.
Further, the sealing plate 42 is also provided with a through hole portion (not shown) at a position facing the COM through hole 41C3, and the COM through electrode 41E provided in the COM through hole 41C3 is inserted therethrough. ing.

In the present embodiment, as the sealing plate 42, the configuration in which the through-hole portion 421 is provided so as to face the opening portion 41C is illustrated, but the present invention is not limited to this. For example, a through-hole portion 421 is formed at a position facing the through-hole 41C2 in a region facing the array region Ar1, and the region facing the other opening 41C (concave groove 41C1) is covered with the sealing plate 42. It is good also as a structure to be called.
In this case, the ultrasonic wave sent out as a back wave from the ultrasonic element 51 to the back surface 41 </ b> A is reflected by the sealing plate 42. At this time, if the phase of the reflected back wave reflected by the sealing plate 42 and the ultrasonic wave emitted from the vibrating part 412B to the working surface 41B side shifts, the ultrasonic wave is attenuated. Therefore, in the case where the groove 41C1 is covered with the sealing plate 42, the acoustic distance between the vibration part 412B and the sealing plate 42 is a quarter of the wavelength λ of the transmitted ultrasonic wave (λ / It is preferable to set the groove depth of each concave groove 41C1 so as to be an odd multiple of 4). In other words, the thickness dimension of each part of the element substrate 41 is set in consideration of the wavelength λ of the ultrasonic wave emitted from the ultrasonic element 51.

(Configuration of acoustic matching layer 43 and acoustic lens 44)
The acoustic matching layer 43 is provided on the operating surface 41B side of the element substrate 41 as shown in FIGS. Specifically, the acoustic matching layer 43 is formed so as to cover each piezoelectric element 413 on the operating surface 41B side of the element substrate 41 and to have a flat surface.
The acoustic lens 44 is provided on the acoustic matching layer 43, and is exposed to the outside from the sensor window 21B of the housing 21, as shown in FIG.
The acoustic matching layer 43 and the acoustic lens 44 efficiently propagate the ultrasonic wave transmitted from the ultrasonic element 51 to the living body to be measured, and efficiently reflect the ultrasonic wave reflected in the living body. To propagate. For this reason, the acoustic matching layer 43 and the acoustic lens 44 are set to an acoustic impedance intermediate between the acoustic impedance of the ultrasonic element 51 of the element substrate 41 and the acoustic impedance of the living body.

[Configuration of Wiring Board 23]
The wiring board 23 is bonded to the ultrasonic device 22 and causes the ultrasonic device 22 to perform ultrasonic transmission / reception processing. The wiring board 23 is provided with a terminal portion 231 at a position facing the through hole 41C2 and the COM through hole 41C3 when the ultrasonic device 22 is bonded. The terminal portion 231 is sealed from the through holes 41C2 and 41C3. The through electrodes 41D and 41E penetrating the plate 42 are electrically connected.
The wiring board 23 is provided with a driver circuit and the like for driving the ultrasonic device 22. Specifically, as shown in FIG. 2, the wiring board 23 includes a terminal portion 231, a common potential circuit 232, a selection circuit 233, a transmission circuit 234, a reception circuit 235, and a connector portion 236 (see FIG. 3). Yes.
The common potential circuit 232 is, for example, a ground circuit, and is connected to the terminal portion 231 that is electrically connected to the COM through electrode 41E in the terminal portion 231. As a result, the common potential circuit 232 applies a common potential (0 potential) to the upper electrode 416 via the COM through electrode 41E.

The selection circuit 233 is connected to each terminal portion 231 that is electrically connected to the through electrode 41D. The selection circuit 233 connects the transmission connection for connecting the ultrasonic device 22 (each terminal unit 231) and the transmission circuit 234 and the ultrasonic device 22 and the reception circuit 235 based on the control of the control device 10. Switch incoming connections.
When the transmission circuit 234 is switched to the transmission connection under the control of the control device 10, the transmission circuit 234 outputs a transmission signal to the effect that the ultrasonic device 22 transmits ultrasonic waves via the selection circuit 233.
When the reception circuit 235 is switched to the reception connection under the control of the control device 10, the reception circuit 235 outputs the reception signal input from the ultrasonic device 22 via the selection circuit 233 to the control device 10. The reception circuit 235 includes, for example, a low-noise amplifier circuit, a voltage control attenuator, a programmable gain amplifier, a low-pass filter, an A / D converter, and the like. The reception circuit 235 converts the received signal into a digital signal, removes a noise component, and is desired. After performing each signal processing such as amplification to the signal level, the received signal after processing is output to the control device 10.

  The connector unit 236 is connected to the transmission circuit 234 and the reception circuit 235. Further, the cable 3 is connected to the connector portion 236, and as described above, the cable 3 is pulled out from the passage hole 21 </ b> C of the housing 21 and connected to the control device 10.

[Configuration of Control Device 10]
As illustrated in FIG. 2, the control device 10 includes, for example, an operation unit 11, a display unit 12, a storage unit 13, and a calculation unit 14. For example, the control device 10 may be a terminal device such as a tablet terminal, a smartphone, or a personal computer, or may be a dedicated terminal device for operating the ultrasonic probe 2.
The operation unit 11 is a UI (User Interface) for the user to operate the ultrasonic measurement apparatus 1 and can be configured by, for example, a touch panel provided on the display unit 12, operation buttons, a keyboard, a mouse, or the like. .
The display unit 12 is configured by a liquid crystal display, for example, and displays an image.
The storage unit 13 stores various programs and various data for controlling the ultrasonic measurement apparatus 1.
The calculation unit 14 is configured by a calculation circuit such as a CPU (Central Processing Unit) and a storage circuit such as a memory. Then, the calculation unit 14 reads and executes various programs stored in the storage unit 13 to control transmission signal generation and output processing with respect to the transmission circuit 234, and to receive signal reception with respect to the reception circuit 235. Controls frequency setting and gain setting.

[Method for Manufacturing Ultrasonic Device 22]
9 and 10 are diagrams illustrating a method for forming the ultrasonic device 22 of the present embodiment. 9 and 10, a cross section along the Y direction of the element substrate 41 is shown.
In the manufacture of the ultrasonic device 22, first, in order to form the element substrate 41, as shown in FIG. 9A, the surface of the substrate main body portion 411 made of Si is oxidized, and further ZrO ₂ is formed on the surface. By forming the film, the vibration film 412 made of a laminate of SiO ₂ and ZrO ₂ is formed.

Thereafter, as shown in FIG. 9B, a piezoelectric element 413 is formed on the vibration film 412.
That is, an electrode material for forming the lower electrode 414 is formed on the working surface 41B side of the vibration film 412, and patterned by etching or the like, whereby the lower electrode 414 (lower electrode body 414A, lower electrode line 414B, electrode) Conductive portion 414C) is formed. Thereafter, a piezoelectric material for forming the piezoelectric film 415 is formed on the operating surface 41B side of the vibration film 412, and is patterned by, for example, etching to form the piezoelectric film 415. Further, an electrode material for forming the upper electrode 416 is formed on the operating surface 41B side of the vibration film 412, and is patterned by, for example, etching, so that the upper electrode 416 (element electrode portion 416A, common electrode portion 416B) and An inter-element electrode layer 417 is formed. Then, an insulating material for forming the insulating layer 418 is formed on the operating surface 41B side of the vibration film 412, and the insulating layer 418 is formed by patterning by etching or the like.

Thereafter, as shown in FIG. 9C, a hole 411A is formed at the position where the opening 41C is formed (the position where the piezoelectric element 413 is formed) from the back surface 41A side of the substrate body 411.
That is, a mask pattern for forming the hole 411A is formed on the back surface 41A side of the substrate body 411, and the hole 411A is formed in the substrate body 411 made of Si, for example, by etching or the like. The etching may be dry etching or wet etching. In the case of wet etching, side etching may reduce the width dimension of the partition wall (support portion 411B) between the hole portions 411A, and therefore dry etching is preferable.
Although illustration is omitted, a COM hole is formed simultaneously with the formation of the hole 411A.

Further, after removing the mask pattern for forming the hole 411A, a mask pattern for forming the hole 412A is formed on the back surface 41A side of the substrate main body 411. This mask pattern is, for example, a pattern in which an opening having the same shape and the same size as the opening on the operating surface 41B side in the hole 412A is provided. Then, the SiO ₂ layer and the ZrO ₂ layer of the vibration film 412 are sequentially etched to form a hole 412A as shown in FIG. 9D. At this time, by forming the mask pattern as described above, etching proceeds along the thickness direction of the vibration film 412 and side etching proceeds in a direction orthogonal to the thickness direction of the vibration film 412. Therefore, a hole 412A having a smaller opening cross-sectional area (in-plane area perpendicular to the thickness direction) is formed in the vibration film 412 from the back surface 41A side toward the working surface 41B side. In the etching process, the lower electrode 414 provided on the operating surface 41B side serves as an etching stopper, and the lower electrode 414 (electrode conducting portion 414C) is exposed on the back surface 41A side of the vibration film 412.
Here, by forming the hole 412A, the through-hole 41C2 is configured by the hole 412A and the previously formed hole 411A, and the vibration film 412 is formed in a region where the hole 412A is not formed. The vibrating part 412B is configured, and the hole 411A and the vibrating part 412B constitute a concave groove 41C1.
Although illustration is omitted, at the same time when the hole 412A is formed, a COM hole is also formed in the vibration film 412, and the COM hole on the substrate body 411 side and the vibration film 412 formed earlier are formed. A COM through hole 41C3 as shown in FIG. 4 is formed by the COM hole.

Thereafter, as shown in FIG. 10A, the sealing plate 42 in which the through-hole portion 421 corresponding to the opening 41C (the concave groove 41C1 and the through-hole 41C2) is formed in advance is attached to the back surface 41A side of the substrate main body 411. To join.
Then, as shown in FIG. 10B, the through hole 41C2 and the COM through hole 41C3 (not shown) are filled with a conductive paste such as Ag paste, for example, and the through electrode 41D and the COM through hole are filled. The electrode 41E is formed.

[Operational effects of the first embodiment]
The ultrasonic measurement apparatus 1 according to this embodiment includes an ultrasonic probe 2 and a control apparatus 10, and the ultrasonic probe 2 includes an ultrasonic device 22 that constitutes an ultrasonic sensor 24 and a wiring board 23. It has been. The element substrate 41 constituting the ultrasonic device 22 is provided with a plurality of openings 41C in the array region Ar1. Many of these openings 41C are concave grooves 41C1, and the piezoelectric element 413 is disposed on the operating surface 41B side of the vibration part 412B that is the bottom surface of the groove. Further, the remainder of the opening 41C is a through hole 41C2, and a through electrode 41D that is electrically connected to the lower electrode 414 constituting the piezoelectric element 413 is inserted therethrough.

In such a configuration, when the ultrasonic device 22 is mounted on the wiring substrate 23, the signal to each piezoelectric element 413 is simply configured by simply bringing the through electrode 41 </ b> D into contact with the terminal portion 231 of the wiring substrate 23. I / O can be performed.
For example, the planar size of the substrate can be reduced as compared with a case where a plurality of lead lines are drawn out from each piezoelectric element 413 to form terminal portions and these terminal portions are connected to a wiring substrate or the like by FPC or the like. Further, in the case where a through electrode that is electrically connected to the piezoelectric element is provided between the openings (for example, the support portion 411B in FIG. 4), it is necessary to secure a space for arranging the through electrode between the openings. The planar size of the substrate is increased. In contrast, in this application example, any one of the plurality of openings arranged in an array is used as a through hole, and a through electrode is provided in the through hole. For this reason, it is not necessary to widen the space | interval between opening parts, and the enlargement of the planar size of a board | substrate by this does not occur.
As described above, in the present embodiment, the planar size of the element substrate 41 can be reduced as compared with the conventional case, and the ultrasonic device 22, the ultrasonic sensor 24, the ultrasonic probe 2, and the ultrasonic measurement apparatus 1 can be downsized. Can do.

In the element substrate 41 of the present embodiment, a plurality of openings 41C are arranged in an array in the array region Ar1, and the through holes 41C2 are provided at positions that are point-symmetric with respect to the array center O. Specifically, the through hole 41C2 is arranged along the diagonal line D1 of the rectangular array region Ar1, and the opening 41C adjacent to the through hole 41C2 in the X direction and the Y direction becomes a concave groove 41C1.
In such a configuration, for example, compared to a configuration in which the through-hole 41C2 is formed in one place in the array region Ar1, the stress balance is uniform, and damage to the element substrate 41 and non-uniform ultrasonic characteristics can be suppressed. .

  In the present embodiment, the piezoelectric element 413 is configured by stacking a lower electrode 414, a piezoelectric film 415, and an upper electrode 416. The through electrode 41D is connected to the lower electrode 414 for applying the SIG signal. Since the lower electrode 414 is an electrode provided on the vibration film 412, the through electrode 41D and the lower electrode 414 can be easily brought into contact with each other by providing the through hole 41C2.

In the present embodiment, one ultrasonic element group 51A is configured by the ultrasonic elements 51 arranged along the X direction, and a plurality of the ultrasonic element groups 51A are arranged along the Y direction to form a one-dimensional array. The structure is structured. The lower electrode 414 is provided across a plurality of ultrasonic elements 51 arranged along the X direction, and the lower electrode 414 of the ultrasonic elements 51 belonging to one ultrasonic element group 51A is electrically connected. Connected and conducted by the through electrode 41D.
In such a configuration, since the distance from each ultrasonic element 51 belonging to the ultrasonic element group 51A to the through electrode 41D is shortened, the electrical resistance is correspondingly reduced, and the influence of the voltage drop can be suppressed.

  Further, since the through holes 41C2 are provided along the diagonal line D1 in the array region Ar1, the intensity distribution of the ultrasonic waves output from the adjacent ultrasonic element groups 51A is substantially the same. For this reason, the wavefronts of the ultrasonic waves transmitted from the respective ultrasonic element groups 51A can be suitably superimposed, and a highly accurate ultrasonic beam can be formed.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described.
In the first embodiment, the example in which the SIG signal is input / output by one through electrode 41D with respect to one ultrasonic element group 51A has been described. On the other hand, the second embodiment is different from the first embodiment in that SIG signals are input / output by two through electrodes 41D with respect to one ultrasonic element group 51A. In the following description, the same reference numerals are given to the configurations already described, and the description thereof is omitted or simplified.

FIG. 11 is a diagram illustrating an arrangement configuration of the opening 41C of the element substrate 41 in the second embodiment. In FIG. 11, white circles indicate the concave grooves 41C1, and black circles indicate the through holes 41C2.
In the present embodiment, as shown in FIG. 11, two of the openings 41C arranged along the X direction become the through holes 41C2. Similar to the first embodiment, these through holes 41C2 are provided with through electrodes 41D and are electrically connected to the lower electrode 414.
Note that the upper electrode 416 is connected to a separately provided COM through electrode 41E (not shown), as in the first embodiment.

Further, as shown in FIG. 11, each through hole 41C2 is arranged along both the diagonal line D1 and the diagonal line D2 in the array region Ar1.
Here, in the ultrasonic element group 51A in the vicinity of the array center O, when the through holes 41C2 are arranged at positions along both the diagonal lines D1 and D2, the through holes 41C2 are arranged at positions adjacent to the X direction and the Y direction. Will be. Even in this case, since the area of the through hole 41C2 is sufficiently small with respect to the total area of the array region Ar1, even if these four through holes 41C2 are adjacent to each other in the X direction and the Y direction, the decrease in the substrate strength is ignored. As much as possible, there is no problem.
However, the opening 41C at a position adjacent to the through hole 41C2 in the X direction and the Y direction is more preferably a concave groove 41C1. In this case, as shown in FIG. 11, in the ultrasonic element group 51A near the array center O, for example, the through hole 41C2 is disposed only at a position along the diagonal line D1, and the concave groove 41C1 is disposed at a position along the diagonal line D2. To do.

  Further, in the ultrasonic element group 51A, when the distance from the through electrode 41D becomes longer, a voltage drop occurs according to the distance, and a difference occurs in the intensity of the ultrasonic wave transmitted from each ultrasonic element 51. For example, in the first embodiment, in the ultrasonic element group 51A arranged at the −Y side end, the through electrode 41D (through hole 41C2) is arranged at the −X side end. In this case, the distance from the penetration electrode 41D to the ultrasonic element 51 arranged at the + X side end is increased, and a voltage drop occurs accordingly, and the intensity of the output ultrasonic wave is reduced.

On the other hand, in this embodiment, the lower electrode 414 is connected to one ultrasonic element group 51A by two through electrodes 41D, and these through electrodes 41D are paired in the array region Ar1. Are arranged along the diagonal lines D1, D2. That is, in one ultrasonic element group 51A, with respect to a virtual line passing through the center point in the X direction and parallel to the Y direction (that is, a virtual line L passing through the array center O and parallel to the Y direction in FIG. 11) The two through electrodes 41D are arranged at positions that are line-symmetric. In such a configuration, the distance from the through electrode 41 </ b> D does not become extremely long with respect to each ultrasonic element 51. In other words, the SIG signal from the through electrode 41D arranged on the −X side is transmitted to the −X side ultrasonic element 51 with respect to the virtual line L, and the + X side ultrasonic element 51 is The SIG signal is transmitted from the through electrode 41D arranged on the + X side. Therefore, the ultrasonic element 51 in which the voltage drop is most likely to occur is an ultrasonic wave whose length from the through electrode 41D is ½ of the length along the X direction of the ultrasonic element group 51A at the maximum. Element 51 (in the case where the through electrode 41D is located at the + X side end and the −X side end, the ultrasonic element 51 near the virtual line L or the through electrode 41D is located on the ± X side when the through electrode 41D is located at the center in the X direction) The ultrasonic element 51) is located at the end.
Therefore, a large voltage drop does not occur as in some ultrasonic element groups 51A in the first embodiment, and the output of ultrasonic waves output from the ultrasonic elements 51 can be made uniform.
Further, even if a voltage drop occurs, the voltage drop occurs at a uniform rate across the virtual line L, so that the intensity of the output ultrasonic wave also becomes a line symmetry distribution across the virtual line L, and the intensity distribution Can be made more uniform.

  In the example shown in FIG. 11, only one through electrode 41D is provided in the ultrasonic element group 51A in the vicinity of the array center O. However, since the arrangement position of the through electrode 41D is a central position along the X direction, the distance from the through electrode 41D to the ultrasonic element 51 farthest from the through electrode 41D is the maximum of the ultrasonic element group 51A as described above. It becomes about 1/2 of the length dimension along the X direction. Therefore, a large influence due to the voltage drop does not occur.

[Operational effects of this embodiment]
In the element substrate 41 of the present embodiment as described above, the through holes 41C2 are arranged point-symmetrically with respect to the array center O in the array region Ar1, as in the first embodiment, and the substrate strength is high. Reduction can be suppressed.
As in the first embodiment, the ultrasonic output intensity distributions of the adjacent ultrasonic element groups 51A are substantially the same, and the ultrasonic wavefronts can be superimposed with high accuracy. Can be output in the direction of.

  Furthermore, in each ultrasonic element group 51A, since the through hole 41C2 is arranged at a position that is line-symmetric with respect to the virtual line L, the distance from the through electrode 41D to each ultrasonic element 51 may become extremely long. Therefore, it is possible to suppress a voltage drop, to output a high-accuracy ultrasonic wave having a uniform intensity distribution, and to form a high-accuracy ultrasonic beam.

[Third embodiment]
Next, a third embodiment according to the present invention will be described.
In the first embodiment and the second embodiment described above, the ultrasonic element group 51A is configured by the ultrasonic elements 51 arranged in the X direction, and a configuration in which a plurality of the ultrasonic element groups 51A are arranged in the Y direction is illustrated. In contrast, in the third embodiment, one ultrasonic element group is configured by arranging n ultrasonic element arrays arranged in the X direction and m arrays in the Y direction. That is, in the third embodiment, the ultrasonic array is configured by n × m partial array regions, and one ultrasonic element group is configured by each partial array region.

FIG. 12 is a diagram showing an arrangement configuration of the opening 41C of the element substrate 41 in the third embodiment. In FIG. 12, white circles indicate the concave grooves 41C1, and black circles indicate the through holes 41C2.
As shown in FIG. 12, in the present embodiment, the array region Ar1 of the ultrasonic element array 50 has a plurality of partial array regions Ar2. In this embodiment, a configuration in which a plurality of partial array regions Ar2 are arranged in the Y direction is illustrated, but the partial array regions Ar2 may be arranged in a two-dimensional array along the X and Y directions.

In each partial array region Ar2, n × m (in this embodiment, 12 × 5) openings 41C are arranged in an array. Similar to the first embodiment, the opening 41C includes a concave groove 41C1 in which the piezoelectric element 413 is disposed, and a through hole 41C2 through which the through electrode 41D is inserted. And the through-hole 41C2 in the opening part 41C is arrange | positioned along the diagonal D3 in each rectangular-shaped partial array area | region Ar2.
In the present embodiment, in the ultrasonic elements 51 of each partial array region Ar2, the lower electrodes 414 are electrically connected to each other, and the same SIG signal is input / output from each through electrode 41D. Thus, one partial array region Ar2 can be functioned as one ultrasonic element group 51A.
Similarly to the first embodiment, the lower electrodes 414 of the ultrasonic elements 51 along the X direction are connected to each other, and conduction between the adjacent ultrasonic elements 51 along the Y direction may be prevented. . Even in this case, if the same SIG signal is applied to the through electrodes 41D provided in each partial array region Ar2 at the same timing, the ultrasonic elements 51 belonging to the partial array region Ar2 can be simultaneously driven.

  Furthermore, in the present embodiment, as in the first and second embodiments, the upper electrode 416 only needs to be electrically connected to the COM through electrode 41E provided outside the array region. Note that any one of the openings 41C in the partial array region Ar2 may be a through hole for COM. In this case, the lower electrode 414 and the piezoelectric film 415 are not stacked on the through-hole, but only the upper electrode is formed so as to cover the COM through-hole, and the through-electrode provided in the COM through-hole is disposed on the upper side. Conduction is made to the electrode 416.

[Operational effects of this embodiment]
In the present embodiment, the array region Ar1 includes a plurality of partial array regions Ar2, and each of these partial array regions Ar2 includes n × m openings 41C. Of these openings 41C, the opening 41C along the diagonal D3 of the partial array region Ar2 is a through hole 41C2, and a through electrode 41D that is electrically connected to the lower electrode 414 is provided.
Even in such a configuration, similarly to the first and second embodiments, the stress balance in each partial array region Ar2 is uniform, and the decrease in the substrate strength can be suppressed.
Each partial array region Ar2 can be driven as one ultrasonic element group 51A (one channel). In this case, the intensity distribution of the ultrasonic waves output from each ultrasonic element group 51A becomes the same distribution, and when forming the ultrasonic beam by superimposing the wavefronts of the output ultrasonic waves, each ultrasonic element group 51A There is no intensity unevenness between the output ultrasonic waves, and it is possible to form a highly accurate ultrasonic beam.

[Modification]
Note that the present invention is not limited to the above-described embodiments, and the present invention includes configurations obtained by modifying, improving, and appropriately combining the embodiments as long as the object of the present invention can be achieved. Is.
In the first embodiment, FIGS. 9 and 10 are illustrated as the method for manufacturing the ultrasonic device 22, but the method is not limited thereto.
For example, a manufacturing method as shown in FIG. 13 may be used.
FIG. 13 is an example showing another method for manufacturing the ultrasonic device 22. In this method, first, as shown in FIG. 13A, the vibration film 412 is formed on the substrate body 411. Thereafter, as shown in FIG. 13B, a hole portion 412A is formed from the operating surface 41B side of the vibrating membrane 412 to the formation position of the through hole 41C2.
Thereafter, as shown in FIG. 13C, a lower electrode 414, a piezoelectric film 415, an upper electrode 416, and an insulating layer 418 are formed on the vibration film 412. Here, the lower electrode 414 is filled in the hole 412A and brought into contact with the substrate body 411.
Thereafter, as shown in FIG. 13D, each hole 411A is formed by etching or the like from the back surface 41A side of the substrate body 411. Thereby, the lower electrode 414 filled in the hole 412A is exposed to the hole 411A. Then, after the sealing plate 42 is joined, the through electrode 41D is inserted, and is conducted to the lower electrode 414.

  Further, in each of the above embodiments and the example illustrated in FIG. 13, the through electrode 41 </ b> D filled in the through hole 41 </ b> C <b> 2 is illustrated, but the present invention is not limited to this. For example, the through electrode 41D that is electrically connected to the lower electrode 414 may be formed by forming a metal thin film on the surface of the through hole 41C2 by metal vapor deposition or the like.

In each of the above embodiments, the example in which the through hole 41C2 is provided along the diagonal line D1 of the array region Ar1 or the pair of diagonal lines D1 and the diagonal line D2 has been described, but the present invention is not limited thereto. The positions of the through holes 41C2 are such that the stress balance in the element substrate 41 is uniform, the substrate strength does not decrease, and the intensity distribution of the ultrasonic waves output from the adjacent ultrasonic element groups 51A is substantially the same. It is sufficient to arrange them.
For example, as shown in FIG. 14, it is good also as a structure which provides the through-hole 41C2 zigzag in the position which becomes point-symmetric with respect to the array center O.

  Moreover, although the opening part 41C adjacent to the X direction and the Y direction with respect to the through hole 41C2 has been described in the above embodiment as an example of the concave groove 41C1, the present invention is not limited thereto. As described above, each opening 41C has a sufficiently small area with respect to the array region Ar1. For example, if the number is a predetermined value or less (for example, 2 to 3), the through holes 41C2 are formed in the X direction or the Y direction. Adjacent configurations may be used.

  In the third embodiment, the example in which the ultrasonic element 51 belonging to one partial array region Ar2 is driven as 1ch has been shown, but the odd-numbered partial array region Ar2 along the Y direction is an ultrasonic transmission array, The even-numbered partial array region Ar2 may be an ultrasonic receiving array.

In each said embodiment, although the ultrasonic device which measures the internal tomographic structure in a living body by performing transmission / reception of an ultrasonic wave was illustrated, it is not limited to this.
For example, as an ultrasonic device, it can also be used as a measuring machine for inspecting a concrete internal structure such as a concrete building.
Moreover, although the ultrasonic measuring apparatus 1 provided with the ultrasonic device 22 was illustrated, it is applicable also to another electronic device. For example, it can be used in an ultrasonic cleaning machine or the like that sends ultrasonic waves to the object to be cleaned and ultrasonically cleans the object to be cleaned.
FIG. 15 is a diagram showing a schematic configuration of an ultrasonic cleaning machine.
The ultrasonic cleaning machine 8 illustrated in FIG. 15 includes a cleaning tank 81 and an ultrasonic module 82 installed on, for example, the bottom surface of the cleaning tank 81.
The ultrasonic module 82 includes the ultrasonic device 22 similar to that of the above embodiment and a wiring board 83 that controls the ultrasonic device 22.
Such an ultrasonic cleaning machine 8 can also obtain the same effect as described above, can reduce the planar size of the element substrate 41, and can easily mount the ultrasonic device 22 on the wiring board 83 by face-down mounting. Can be implemented. For this reason, size reduction of the ultrasonic cleaning machine 8 can be achieved.
Moreover, although the electronic device provided with the ultrasonic module was illustrated as said each embodiment and FIG. 15 as an electronic device, it is not limited to the piezoelectric module for transmission / reception of an ultrasonic wave.
For example, the piezoelectric module of the present invention can be applied to a pressure sensor or the like. In this case, the displacement amount of the vibration part 412B displaced by the pressure medium (for example, gas or liquid) is measured by detecting the electromotive force generated in the piezoelectric film 415, and the pressure of the pressure medium is determined from the displacement amount of the vibration part 412B. taking measurement.

  In addition, the specific structure for carrying out the present invention may be configured by appropriately combining the above-described embodiments and modifications within the scope that can achieve the object of the present invention, and may be appropriately changed to other structures and the like. May be.

  DESCRIPTION OF SYMBOLS 1 ... Ultrasonic measuring apparatus (ultrasonic apparatus), 8 ... Ultrasonic cleaning machine (ultrasonic apparatus), 22 ... Ultrasonic device, 23 ... Wiring board, 24 ... Ultrasonic sensor, 41 ... Element board | substrate, 41A ... Back surface ( (Second surface), 41B ... acting surface (first surface), 41C ... opening, 41C1 ... concave groove, 41C2 ... through hole, 41D ... through electrode, 42 ... sealing plate (back substrate), 50 ... ultrasound element Array, 51 ... Ultrasonic element, 51A ... Ultrasonic element group, 82 ... Ultrasonic module, 83 ... Wiring board, 231 ... Terminal part, 232 ... Common potential circuit, 233 ... Selection circuit, 234 ... Transmission circuit, 235 ... Reception Circuit, 411... Substrate body, 411A. 414C ... Electrode conduction Part, 415 ... piezoelectric film, 416 ... upper electrode, 421 ... through hole, Ar1 ... array region, Ar2 ... partial array region, D1 ... diagonal line, D2 ... diagonal line, D3 ... diagonal line, L ... virtual line, O ... array center .

Claims (11)

An element substrate having a first surface and a second surface opposite to the first surface, wherein a plurality of openings that are open on the second surface side in a predetermined array region are arranged in an array;
A plurality of piezoelectric elements provided on the first surface side of the element substrate,
Any of the plurality of openings is a through-hole penetrating the element substrate in the substrate thickness direction, and the other openings are concave grooves,
The piezoelectric element is provided on the first surface side in the groove bottom surface of the concave groove,
The through hole is provided with a through electrode that penetrates from the first surface to the second surface of the element substrate and is electrically connected to the piezoelectric element on the first surface side. A piezoelectric element substrate. The piezoelectric element substrate according to claim 1,
The piezoelectric element substrate, wherein the through hole is provided at a position that is point-symmetric with respect to a center of the array region. In the piezoelectric element substrate according to claim 1 or 2,
The piezoelectric element substrate, wherein the opening adjacent to the through hole is the concave groove. The piezoelectric element substrate according to any one of claims 1 to 3,
The piezoelectric element is constituted by a laminate in which a first electrode layer, a piezoelectric film, and a second electrode layer are laminated from the groove bottom side of the groove,
The piezoelectric element substrate, wherein the through electrode is connected to the first electrode layer. The piezoelectric element substrate according to claim 4,
The openings are arranged in an array along a first direction and a second direction intersecting the first direction,
One piezoelectric element group is configured by the piezoelectric elements arranged along the first direction, and a plurality of the piezoelectric element groups are arranged along the second direction in the array region, and the same piezoelectric element The first electrode layers of the piezoelectric elements belonging to a group are electrically connected to each other;
At least one of the plurality of openings arranged along the first direction is the through-hole. In the piezoelectric element substrate according to claim 5,
The through-hole is provided along at least one of two diagonal lines of the rectangular array region surrounded by two sides along the first direction and two sides along the second direction. A piezoelectric element substrate. In the piezoelectric element substrate according to claim 5 or 6,
The through-holes are provided at positions that pass through the center of the piezoelectric element group along the first direction and are symmetrical with respect to a virtual line along the second direction. substrate. The piezoelectric element substrate according to claim 1,
The openings are arranged in an array along a first direction and a second direction intersecting the first direction,
The array region includes a plurality of partial array regions, and each partial array region includes n × m openings formed by n pieces along the first direction and m pieces along the second direction. Arranged in a shape,
In each partial array region, the through-hole is provided at a position that is point-symmetric with respect to the center of the partial array region. An element substrate having a first surface and a second surface opposite to the first surface, and a plurality of openings that are open on the second surface side in a predetermined array region; and A plurality of piezoelectric elements provided on the first surface side of the element substrate, and a piezoelectric element substrate,
A back substrate bonded to the second surface of the element substrate;
A wiring board, and
Any of the plurality of openings is a through-hole penetrating the element substrate in the substrate thickness direction, and the other openings are concave grooves,
The piezoelectric element is provided on the first surface side in the groove bottom surface of the concave groove,
The through hole is provided with a through electrode that penetrates from the first surface to the second surface of the element substrate and is electrically connected to the piezoelectric element on the first surface side,
The rear substrate has a second through electrode that is electrically connected to the through electrode and penetrates the substrate thickness direction;
The said wiring board was provided in the position corresponding to each of said 2nd penetration electrode, and was provided with the terminal part electrically connected with the said 2nd penetration electrode. The piezoelectric module characterized by the above-mentioned. An element substrate having a first surface and a second surface opposite to the first surface, and a plurality of openings that are open on the second surface side in a predetermined array region; and A plurality of piezoelectric elements provided on the first surface side of the element substrate, and a piezoelectric element substrate,
A back substrate bonded to the second surface of the element substrate;
A wiring board, and
Any of the plurality of openings is a through-hole penetrating the element substrate in the substrate thickness direction, and the other openings are concave grooves,
The piezoelectric element is provided on the first surface side in the groove bottom surface of the concave groove,
The through hole is provided with a through electrode that penetrates from the first surface to the second surface of the element substrate and is electrically connected to the piezoelectric element on the first surface side,
The rear substrate has a second through electrode that is electrically connected to the through electrode and penetrates the substrate thickness direction;
The wiring board is provided at a position corresponding to each of the second through electrodes, a terminal portion electrically connected to the second through electrodes, and electrically connected to the terminal portions. Drive that performs at least one of an ultrasonic transmission process that outputs a drive signal to output an ultrasonic wave and an ultrasonic reception process that detects an ultrasonic wave based on a detection signal input from the piezoelectric element And an ultrasonic module. An element substrate having a first surface and a second surface opposite to the first surface, and a plurality of openings that are open on the second surface side in a predetermined array region; and A plurality of piezoelectric elements provided on the first surface side of the element substrate, and a piezoelectric element substrate,
A back substrate bonded to the second surface of the element substrate;
A wiring board;
A control unit,
Any of the plurality of openings is a through-hole penetrating the element substrate in the substrate thickness direction, and the other openings are concave grooves,
The piezoelectric element is provided on the first surface side in the groove bottom surface of the concave groove,
The through hole is provided with a through electrode that penetrates from the first surface to the second surface of the element substrate and is electrically connected to the piezoelectric element on the first surface side,
The rear substrate has a second through electrode that is electrically connected to the through electrode and penetrates the substrate thickness direction;
The wiring board is provided at a position corresponding to each of the second through electrodes, a terminal portion electrically connected to the second through electrodes, and electrically connected to the terminal portions. Drive that performs at least one of an ultrasonic transmission process that outputs a drive signal to output an ultrasonic wave and an ultrasonic reception process that detects an ultrasonic wave based on a detection signal input from the piezoelectric element A circuit,
The control device controls at least one of the ultrasonic transmission processing and the ultrasonic reception processing using the drive circuit and the plurality of piezoelectric elements.

Images