JP2013090064A - Vibration piece, vibrator and piezoelectric device - Google Patents

Abstract

To provide a resonator element, a vibrator, and a piezoelectric device capable of efficiently exciting thickness shear vibration while suppressing vibration other than thickness shear vibration.
A resonator element includes a first piezoelectric substrate that vibrates in thickness, a second piezoelectric substrate that is laminated on the first piezoelectric substrate and vibrates in thickness, and a first piezoelectric substrate. The excitation electrode 23a bonded to the surface of the body substrate 21 opposite to the second piezoelectric substrate 22 and the surface of the second piezoelectric substrate 22 opposite to the first piezoelectric substrate 21 are bonded to each other. The excitation electrode 23c, the excitation electrode 23b provided between the first piezoelectric substrate 21 and the second piezoelectric substrate 22, and the side surfaces of the first piezoelectric substrate 21 and the second piezoelectric substrate 22. The first side surface electrode that is electrically connected to the excitation electrode 23a and the excitation electrode 23c, and the second side surface electrode that is provided on the side surface of the second piezoelectric substrate 22 and is electrically connected to the excitation electrode 23b. Side electrode.
[Selection] Figure 2

Description

  The present invention relates to a resonator element, a vibrator, and a piezoelectric device.

As a vibrator such as a quartz vibrator provided in a piezoelectric device such as a quartz oscillator, one utilizing thickness shear vibration is known (for example, see Patent Document 1).
For example, as disclosed in Patent Document 1, such a vibrator includes a vibrating piece that is configured using one piezoelectric substrate whose thickness vibration is a main vibration. Then, a thickness shear vibration is excited by applying a voltage to the piezoelectric substrate in the thickness direction.

Further, in the vibrator of Patent Document 1, by using a resonator element having a so-called mesa structure, the thickness shear vibration is confined to improve the Q value, and as a result, the CI value (crystal impedance) is reduced. .
However, in the above-described conventional structure, in order to manufacture a thickness sliding vibrating piece that vibrates at a specific frequency, a piezoelectric substrate having a specific thickness corresponding to the frequency must be used between the pair of excitation electrodes. There is a limit to the magnitude of the electric field that can be generated between the excitation electrodes, and as a result, it has been difficult to sufficiently reduce the CI value.

JP 2008-263387 A

  An object of the present invention is to provide a resonator element, a vibrator, and a piezoelectric device capable of efficiently exciting thickness shear vibration while suppressing vibration other than thickness shear vibration.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
[Application Example 1]
The resonator element according to the aspect of the invention includes a first substrate that excites thickness shear vibration,
A second substrate laminated on the first substrate and exciting thickness shear vibration;
A first excitation electrode disposed on a main surface of the first substrate opposite to the second substrate;
A second excitation electrode disposed on a main surface of the second substrate opposite to the first substrate;
A third excitation electrode disposed between the first substrate and the second substrate;
A first side electrode disposed on a side surface of the first substrate and the second substrate and electrically connecting the first excitation electrode and the second excitation electrode;
A second side electrode disposed on a side surface of at least one of the first substrate and the second substrate and electrically connected to the third excitation electrode;
It is characterized by providing.

According to the resonator element configured as above, by applying a voltage between the first side electrode and the second side electrode, between the first excitation electrode and the third excitation electrode, and An electric field can be generated between the second excitation electrode and the third excitation electrode. Thereby, the first substrate and the second substrate can be vibrated in thickness sliding.
In particular, it is possible to increase the displacement amount of the thickness shear vibration of the entire resonator element while reducing the thickness of the first substrate and the second substrate to suppress the voltage applied to each substrate. For this reason, it is possible to efficiently excite the thickness shear vibration while suppressing vibrations other than the thickness shear vibration.

[Application Example 2]
In the resonator element according to the aspect of the invention, it is preferable that each of the first substrate and the second substrate is a piezoelectric substrate made of a piezoelectric material.
Thereby, thickness shear vibration can be efficiently excited while suppressing vibrations other than thickness shear vibration.

[Application Example 3]
In the resonator element according to the aspect of the invention, it is preferable that the first substrate and the second substrate are bonded to each other via the third excitation electrode.
As a result, the configuration of the resonator element can be made relatively simple.
[Application Example 4]
The resonator element according to the aspect of the invention may include a spacer layer that is spaced apart from the third excitation electrode and disposed between the first substrate and the second substrate in the vicinity of the first side electrode. Is preferred.
Accordingly, the first side electrode can be easily formed by various film forming methods. Further, disconnection of the first side electrode between the first substrate and the second substrate can be prevented.

[Application Example 5]
In the resonator element according to the aspect of the invention, the first substrate may be disposed on a main surface opposite to the second substrate, and may be extended from the first excitation electrode toward a side surface of the first substrate. A first extraction electrode,
A second extraction electrode disposed on a main surface of the second substrate opposite to the first substrate and extending from the second excitation electrode toward a side surface of the second substrate; When,
With
Preferably, the first extraction electrode and the second extraction electrode are electrically connected to each other via the first side electrode.
This facilitates the design of the first excitation electrode, the second excitation electrode, and the first side electrode.

[Application Example 6]
In the resonator element according to the aspect of the invention, the resonator element is disposed between the first substrate and the second substrate, and extends from the third excitation electrode toward a side surface of the first substrate or the second substrate. A third extraction electrode that is
The third extraction electrode is preferably electrically connected to the second side electrode.
This facilitates the design of the third excitation electrode and the second side electrode.

[Application Example 7]
In the resonator element according to the aspect of the invention, on the main surface of the first substrate or the second substrate opposite to the third excitation electrode,
A first electrode pad electrically connected to the first side electrode;
A second electrode pad electrically connected to the second side electrode;
Is preferably arranged.
Accordingly, the first electrode pad and the second electrode pad can be electrically connected to the mount electrode on the base substrate by mounting the resonator element on the base substrate with a conductive adhesive or the like.

[Application Example 8]
In the resonator element according to the aspect of the invention, it is preferable that each of the first substrate and the second substrate is a quartz substrate.
As a result, it is possible to excite the thickness shear vibration with higher accuracy with desired vibration characteristics.
[Application Example 9]
In the resonator element according to the aspect of the invention, it is preferable that the crystal substrate is a crystal rotation Y plate.
Thereby, thickness shear vibration can be efficiently excited in the first substrate and the second substrate, respectively.

[Application Example 10]
In the resonator element according to the aspect of the invention, it is preferable that the crystal rotation Y plate is any one of an AT cut crystal substrate, a BT cut crystal substrate, and an SC cut crystal substrate.
Thereby, thickness shear vibration can be efficiently excited in the first substrate and the second substrate, respectively.

[Application Example 11]
In the resonator element according to the aspect of the invention, the first substrate and the second substrate are crystal substrates having the same cut angle,
It is preferable that the crystal axis of one crystal substrate is in the same direction as the crystal axis obtained by rotating the other crystal substrate by 180 ° around the Y ′ axis or the Z ′ axis.
As a result, by applying a voltage to the first substrate and the second substrate so that their joint surfaces have the same polarity, thickness shear vibrations in the same direction are excited on the first substrate and the second substrate. Can be made.

[Application Example 12]
The vibrator of the present invention includes the resonator element of the present invention,
A package for storing the resonator element;
It is characterized by providing.
Accordingly, it is possible to provide a vibrator that can efficiently excite thickness shear vibration while suppressing vibration other than thickness shear vibration.
[Application Example 13]
The piezoelectric device of the present invention includes the vibrator of the present invention.
Accordingly, it is possible to provide a piezoelectric device that can efficiently excite thickness shear vibration while suppressing vibration other than thickness shear vibration.

1 is a top view showing a piezoelectric device (vibrator) according to a first embodiment of the present invention. It is sectional drawing of the piezoelectric device shown in FIG. FIG. 2 is a perspective view showing a resonator element provided in the piezoelectric device shown in FIG. 1. FIG. 4 is a diagram illustrating a second piezoelectric substrate, a second excitation electrode, and a third excitation electrode of the resonator element illustrated in FIG. 3. FIG. 3 is a schematic diagram for explaining an operation of a vibrating piece provided in the piezoelectric device shown in FIG. 2. FIG. 6 is a diagram for explaining a first example in which the first piezoelectric substrate and the second piezoelectric substrate provided in the resonator element of the operation illustrated in FIG. 5 are configured using AT-cut quartz. FIG. 6 is a diagram for explaining a second example in which the first piezoelectric substrate and the second piezoelectric substrate provided in the resonator element of the operation illustrated in FIG. 5 are configured using AT-cut quartz. It is sectional drawing of the vibration piece with which the piezoelectric device concerning 2nd Embodiment of this invention was equipped. FIG. 9 is a diagram illustrating a second piezoelectric substrate, a second excitation electrode, and a third excitation electrode of the resonator element illustrated in FIG. 8. It is sectional drawing of the vibration piece with which the piezoelectric device concerning 3rd Embodiment of this invention was equipped. It is sectional drawing of the vibration piece with which the piezoelectric device concerning 4th Embodiment of this invention was equipped. It is sectional drawing of the vibration piece with which the piezoelectric device concerning 5th Embodiment of this invention was equipped. It is sectional drawing of the vibration piece with which the piezoelectric device concerning 6th Embodiment of this invention was equipped.

Hereinafter, as an example of the piezoelectric device of the present invention, a piezoelectric vibrator and a piezoelectric device with electronic components will be described in detail based on embodiments shown in the accompanying drawings.
<First Embodiment>
First, a first embodiment of the present invention will be described.
1 is a top view showing a piezoelectric device (vibrator) according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of the piezoelectric device shown in FIG. 1, and FIG. 3 is provided in the piezoelectric device shown in FIG. 4 is a perspective view showing the obtained vibrating piece, FIG. 4 is a view showing the second piezoelectric substrate, the second excitation electrode, and the third excitation electrode of the vibrating piece shown in FIG. 3, and FIG. 5 is shown in FIG. FIG. 6 is a schematic diagram for explaining the operation of the resonator element included in the piezoelectric device. FIG. 6 is an AT cut diagram illustrating the first piezoelectric substrate and the second piezoelectric substrate included in the resonator element operating as shown in FIG. FIG. 7 is a diagram for explaining a first example in the case of using the quartz of FIG. 7, and FIG. 7 shows the first piezoelectric substrate and the second piezoelectric substrate provided in the resonator element of the operation shown in FIG. It is a figure for demonstrating the 2nd example in the case of comprising using an AT cut crystal. In the following description, for convenience of explanation, the upper side in FIG. 2 is referred to as “upper”, the lower side as “lower”, the right side as “right”, and the left side as “left”.
A piezoelectric device 1 shown in FIG. 1 includes a resonator element 2 and a package (housing) 3 that accommodates the resonator element 2.

First, the resonator element 2 will be described.
As shown in FIG. 1 or FIG. 2, the resonator element (piezoelectric resonator element) 2 includes a first piezoelectric substrate (first substrate) 21 and a second piezoelectric substrate (second substrate) 22 having a longitudinal shape. An excitation electrode (first excitation electrode) 23a and a connection electrode (first extraction electrode) 24a provided on the upper surface of the first piezoelectric substrate 21, and the first piezoelectric substrate 21 and the second piezoelectric substrate. The excitation electrode (third excitation electrode) 23b and the connection electrode (third extraction electrode) 24b provided between the body substrate 22 and the excitation electrode (first electrode) provided on the lower surface of the second piezoelectric substrate 22 2 excitation electrodes) 23c and connection electrodes (second extraction electrodes) 24c.
Further, as shown in FIG. 3, the resonator element 2 includes a side electrode (first side electrode) 25 a and a side electrode (second side electrode) 25 b. Furthermore, as illustrated in FIG. 4, the resonator element 2 includes an electrode pad (first electrode pad) 26 a and an electrode pad (second electrode pad) 26 b, and a spacer layer 27.

Hereinafter, each part which comprises the vibration piece 2 is demonstrated in detail sequentially.
The first piezoelectric substrate 21 and the second piezoelectric substrate 22 excite thickness shear vibration as main vibration by applying a voltage (electric field) in the thickness direction.
In particular, as shown in FIG. 5, the first piezoelectric substrate 21 and the second piezoelectric substrate 22 are configured to undergo thickness-shear vibration in the same direction. In other words, the first piezoelectric substrate 21 and the second piezoelectric substrate 22 are configured to undergo thickness-slip vibration so that the surfaces (bonding surfaces) facing each other are displaced in opposite directions. Yes. In FIG. 5, for convenience of explanation, illustration of the side electrode, the lead electrode, and the electrode pad is omitted.

  Such a resonator element 2 includes a laminated body in which a plurality of piezoelectric substrates that vibrate in thickness shear are laminated, thereby reducing the thickness of each of the first piezoelectric substrate 21 and the second piezoelectric substrate 22. Therefore, even if the voltage applied to each piezoelectric substrate is suppressed, the required electric field is generated between the pair of excitation electrodes, and the displacement of the thickness shear vibration of the entire resonator element 2 can be increased. For this reason, it is possible to efficiently excite the thickness shear vibration while suppressing vibrations other than the thickness shear vibration.

  More specifically, the first piezoelectric substrate 21 and the second piezoelectric substrate 22 are bonded to each other via an excitation electrode 23b which is an electrode layer described in detail later. That is, the excitation electrode 23 b also has a function as a bonding layer for bonding the first piezoelectric substrate 21 and the second piezoelectric substrate 22. Thereby, the structure of the resonator element 2 can be made relatively simple.

In the present embodiment, a spacer layer 27 is provided between the first piezoelectric substrate 21 and the second piezoelectric substrate 22 in addition to the excitation electrode 23b and the connection electrode 24b (see FIG. 4). . The spacer layer 27 is provided so as to be separated from the excitation electrode 23b and the connection electrode 24b and to fill a gap between the first piezoelectric substrate 21 and the second piezoelectric substrate 22 in the vicinity of the side electrode 25a. It has been. Thereby, the side electrode 25a described in detail later can be easily formed by various film forming methods. Further, disconnection of the side electrode 25a between the first piezoelectric substrate 21 and the second piezoelectric substrate 22 can be prevented. Furthermore, the spacer layer 27 also functions as a bonding layer for bonding the first piezoelectric substrate 21 and the second piezoelectric substrate 22, thereby increasing the mechanical strength of the resonator element 2 and increasing the reliability of the resonator element 2. Can be improved.
For this reason, in the present embodiment, the first piezoelectric substrate 21 and the second piezoelectric substrate 22 have voltages in the thickness direction such that their joint surfaces (surfaces facing each other) have the same polarity. By being applied, they are configured to vibrate in thickness sliding in the same direction.

Accordingly, the first piezoelectric substrate 21 and the second piezoelectric substrate 22 are bonded to the first piezoelectric substrate 21 and the second piezoelectric substrate 22 through the excitation electrode 23b (electrode layer) with a relatively simple configuration. The piezoelectric substrates 22 can be vibrated by thickness sliding in the same direction. Further, it is possible to reduce a loss of mutual thickness-shear vibration between the first piezoelectric substrate 21 and the second piezoelectric substrate 22.
Each of the first piezoelectric substrate 21 and the second piezoelectric substrate 22 is made of a piezoelectric material. Examples of the piezoelectric material include quartz, lithium tantalate, lithium niobate, and boric acid. Examples thereof include lithium and barium titanate. Among these, quartz is preferable as the piezoelectric material.

When at least one of the first piezoelectric substrate 21 and the second piezoelectric substrate 22 is made of quartz, it is possible to excite thickness-shear vibration with desired vibration characteristics with high accuracy.
In particular, when the first piezoelectric substrate 21 and the second piezoelectric substrate 22 are each made of quartz, it is possible to excite thickness-shear vibration with desired vibration characteristics with higher accuracy.
When each of the first piezoelectric substrate 21 and the second piezoelectric substrate 22 is made of quartz, it is preferable to use a quartz rotating Y plate as the quartz. Thereby, thickness shear vibration can be efficiently excited in the first piezoelectric substrate 21 and the second piezoelectric substrate 22, respectively.

  Further, when each of the first piezoelectric substrate 21 and the second piezoelectric substrate 22 is made of crystal, the cut angle of the crystal is any one of AT cut, BT cut, and SC cut. preferable. That is, the quartz substrate constituting the first piezoelectric substrate 21 and the second piezoelectric substrate 22 is preferably one of an AT cut quartz substrate, a BT cut quartz substrate, and an SC cut quartz substrate. Thereby, thickness shear vibration can be efficiently excited in the first piezoelectric substrate 21 and the second piezoelectric substrate 22, respectively.

  Further, when the first piezoelectric substrate 21 and the second piezoelectric substrate 22 are composed of piezoelectric crystal plates having the same cut angle, the direction of the electric field applied to the first piezoelectric substrate 21 and the second piezoelectric substrate The second piezoelectric substrate with respect to the first piezoelectric substrate 21 so that the thickness-shear vibration phases of the two piezoelectric substrates are in phase even if the direction of the electric field applied to the body substrate 22 is opposite. It is desirable that 22 is arranged upside down or left and right. That is, the crystal axis of the second piezoelectric substrate 22 is preferably in the same direction as the crystal axis obtained by rotating the first piezoelectric substrate 21 by 180 ° around the Y ′ axis or the Z ′ axis. In other words, the first piezoelectric substrate 21 and the second piezoelectric substrate 22 have the Y′-axis or Z′-axis crystal axes parallel to each other and the crystal axes other than the crystal axes are mutually Parallel to the reverse direction.

  Crystal has an X axis (electrical axis), a Y axis (mechanical axis), and a Z axis (optical axis) orthogonal to each other as crystal axes. The “Z ′ axis” is the Z axis centered on the X axis. Is an axis inclined by a predetermined angle in the Y-axis direction of the Y-axis, and the “Y′-axis” is an axis inclined by a predetermined angle in the + Z-axis direction of the Z-axis around the X-axis. is there. The “crystal rotation Y plate” is a crystal substrate having a plate surface parallel to the X-axis and the Z′-axis and having a direction parallel to the Y′-axis as a thickness direction.

  For example, when the first piezoelectric substrate 21 and the second piezoelectric substrate 22 are configured using a plate-like crystal having an AT cut (hereinafter referred to as an AT plate), as shown in FIG. By joining the lower surface 102 of the AT plate 100 which is a non-rotating AT plate and the upper surface 101a of the AT plate 100a obtained by rotating the non-rotating AT plate 180 ° around the Z ′ axis through the excitation electrode 23b. The first piezoelectric substrate 21 composed of the AT plate 100 and the second piezoelectric substrate 22 composed of the AT plate 100a can be obtained. The AT plate 100 vibrates in the thickness direction in the X axis direction by applying a voltage in the thickness direction (Y ′ axis direction).

Further, as shown in FIG. 7, the lower electrode 102 of the AT plate 100 which is a non-rotating AT plate and the upper surface 101b of the AT plate 100b obtained by rotating the non-rotating AT plate by 180 ° around the Y ′ axis are excitation electrodes. By joining via 23b, the 1st piezoelectric substrate 21 comprised by AT board 100 and the 2nd piezoelectric substrate 22 comprised by AT board 100b can be obtained.
In this way, by applying a voltage to the first piezoelectric substrate 21 and the second piezoelectric substrate 22 so that their joint surfaces have the same polarity, the first piezoelectric substrate 21 and the second piezoelectric substrate 21 Thickness-shear vibrations in the same direction can be excited in the piezoelectric substrate 22.

As shown in FIGS. 6 and 7, when the first piezoelectric substrate 21 and the second piezoelectric substrate 22 are configured using quartz crystals having the same cut angle, the resonator element in which two AT plates are joined together. The frequency of the thickness-shear vibration of 2 is half of the frequency of the vibration when a single AT plate is caused to undergo thickness-shear vibration alone.
In other words, when the frequency of thickness-shear vibration of the resonator element 2 is F [Hz], two AT plates that perform thickness-shear vibration at 2 F [Hz] may be used.

  The average thicknesses of the first piezoelectric substrate 21 and the second piezoelectric substrate 22 are determined according to the drive frequency of the resonator element 2 and the like, and are not particularly limited. The piezoelectric substrate 21 and the second piezoelectric substrate 22 may have the same thickness or different thicknesses, but one thickness is set to be an integral multiple of the other thickness. Is preferred. As a result, it is possible to efficiently vibrate and vibrate the entire resonator element 2 at a desired frequency.

As shown in FIGS. 1 and 2, the excitation electrode 23 a is provided so as to cover the central portion of the upper surface (main surface) of the first piezoelectric substrate 21. In addition, a connection electrode 24a is provided at the left end portion in the longitudinal direction and one end portion in the short direction of the upper surface of the first piezoelectric substrate 21, and the excitation electrode 23a and the connection electrode 24a are electrically connected to each other. It is connected.
The excitation electrode 23 b is provided so as to cover the center of the lower surface (main surface) of the first piezoelectric substrate 21 and the upper surface (main surface) of the second piezoelectric substrate 22. In addition, a connection electrode 24b is provided at the left end in the longitudinal direction and the other end in the short direction of the upper surface of the second piezoelectric substrate 22, and the excitation electrode 23b and the connection electrode 24b are electrically connected. It is connected to the.

In addition, the excitation electrode 23 c is provided so as to cover the central portion of the lower surface (main surface) of the second piezoelectric substrate 22. In addition, a connection electrode 24c is provided at one end of the lower surface of the second piezoelectric substrate 22 in the longitudinal direction and in the lateral direction (the end opposite to the connection electrode 24b). The excitation electrode 23c and the connection electrode 24c are electrically connected.
Furthermore, the side electrode (first side electrode) 25 a is provided on the side surfaces (specifically, the left side surface in FIG. 2) of the first piezoelectric substrate 21 and the second piezoelectric substrate 22. The side electrode 25a electrically connects the excitation electrode 23a and the excitation electrode 23c.

Further, the side electrode (second side electrode) 25b is provided on the side surface of the second piezoelectric substrate 22 (specifically, the left side surface in FIG. 2). The side electrode 25b is electrically connected to the excitation electrode 23b.
By applying a voltage between the side electrode 25a and the side electrode 25b, an electric field is generated between the excitation electrode 23a and the excitation electrode 23b and between the excitation electrode 23b and the excitation electrode 23c. be able to. Thereby, the first piezoelectric substrate 21 and the second piezoelectric substrate 22 can be caused to undergo thickness-shear vibration, respectively.

Here, the connection electrode (first extraction electrode) 24a is joined to the surface of the first piezoelectric substrate 21 opposite to the second piezoelectric substrate 22, and the excitation electrode 23a to the first piezoelectric substrate. It extends toward the side surface 21 (the left side surface in FIG. 2).
The connection electrode (second lead electrode) 24b is bonded to the surface of the second piezoelectric substrate 22 opposite to the first piezoelectric substrate 21, and the excitation electrode 23c to the second piezoelectric substrate 22 are joined. It is extended toward the side of the.

The connection electrode 24a and the connection electrode 24b are electrically connected to each other through the side electrode 25a. This facilitates the design of the excitation electrodes 23a and 23c and the side electrode 25a.
The connection electrode (third connection electrode) 24b is provided between the first piezoelectric substrate 21 and the second piezoelectric substrate 22, and is provided on the side surface of the second piezoelectric substrate 22 from the excitation electrode 23b. It is extended toward.

Such a connection electrode 24b is electrically connected to the side electrode 25b. Thereby, the design of the excitation electrode 24b and the side electrode 25b becomes easy.
The electrode pads 26a and 26b are bonded to the lower surface of the second piezoelectric substrate 22 (that is, the surface opposite to the excitation electrode 23b).
The electrode pad 26a is electrically connected to the side electrode 25a, while the electrode pad 26b is electrically connected to the side electrode 25b. Thus, the electrode pads 26a and 26b can be electrically connected to the mount electrodes 34a and 34b on the base substrate 31 by mounting the resonator element 2 on the base substrate 31 described later with a conductive adhesive or the like. it can.

  Therefore, when a voltage is applied between the mount electrode 34a and the mount electrode 34b, the first piezoelectric substrate 21 and the second piezoelectric substrate 21 and the second piezoelectric substrate 21 are generated at a certain frequency (resonance frequency) due to the inverse piezoelectric effect of the piezoelectric material as described above. The piezoelectric substrate 22 can be vibrated by thickness sliding. Further, when the first piezoelectric substrate 21 and the second piezoelectric substrate 22 vibrate, there is a certain frequency between the excitation electrodes 23a and 23b and between the excitation electrodes 23b and 23c due to the piezoelectric effect of the piezoelectric material. Voltage is generated. Utilizing these properties, the piezoelectric device 1 can generate an electrical signal that vibrates at a resonance frequency.

Here, the excitation electrodes 23a, 23b, and 23c are formed so as to have regions overlapping each other.
In the present embodiment, the excitation electrodes 23a, 23b, and 23c are formed so as to coincide with each other when the resonator element 2 is viewed in plan. Then, the thickness-shear vibration as described above is excited in a region of the first piezoelectric substrate 21 sandwiched between the excitation electrode 23a and the excitation electrode 23b. In addition, in the region sandwiched between the excitation electrode 23b and the excitation electrode 23c in the second piezoelectric substrate 22, the thickness shear vibration as described above is excited.

The excitation electrodes 23a, 23b, 23c, the connection electrodes 24a, 24b, 24c, the side electrodes 25a, 25b, the electrode pads 26a, 26b, and the spacer layer 27 are made of aluminum, aluminum alloy, silver, silver alloy, chromium, respectively. Further, it can be formed of a metal material having excellent conductivity such as chromium alloy or gold.
Examples of methods for forming these electrodes include physical film formation methods such as sputtering and vacuum deposition, chemical vapor deposition methods such as CVD, and various coating methods such as an ink jet method.

  More specifically, the excitation electrode 23a and the connection electrode 24a can be collectively formed on the upper surface of the first piezoelectric substrate 21 using the film forming method. Further, the excitation electrode 23b, the connection electrode 24b, and the spacer layer 27 can be collectively formed on the upper surface of the second piezoelectric substrate 22 by using the above film forming method. Further, the excitation electrode 23c, the connection electrode 24c, and the electrode pads 26a and 26b can be collectively formed on the lower surface of the second piezoelectric substrate 22 by using the film forming method. Further, the side electrodes 25a and 25b are formed on the first piezoelectric substrate 21 after the excitation electrodes 23a, 23b and 23c, the connection electrodes 24a, 24b and 24c, the electrode pads 26a and 26b and the spacer layer 27 are formed as described above. And the second piezoelectric substrate 22 can be bonded together, and then formed together using the film forming method.

  The excitation electrode 23b described above also has a function of bonding the first piezoelectric substrate 21 and the second piezoelectric substrate 22 together. For example, the excitation electrode 23b is formed by depositing a metal material as described above on the upper surface of the second piezoelectric substrate 22, and then performing plasma treatment or the like on the surface of the film to develop adhesiveness. The first piezoelectric substrate 21 and the second piezoelectric substrate 22 are joined by pressing the piezoelectric substrate 21. Further, after the metal materials described above are formed on the lower surface of the first piezoelectric substrate 21 and the upper surface of the second piezoelectric substrate 22, respectively, the films may be plasma-bonded.

Next, the package 3 that houses and fixes the resonator element 2 will be described.
The package 3 has a substantially rectangular shape in plan view. As shown in FIG. 2, the package 3 includes a plate-shaped base substrate 31, a frame-shaped frame member 32, and a plate-shaped lid member 33. The base substrate 31, the frame member 32, and the lid member 33 are stacked in this order from below, and the base substrate 31, the frame member 32, and the frame member 32 and the lid member 33 are joined by an adhesive or a brazing material, respectively. ing. The package 3 houses the resonator element 2 in an internal space S defined by the base substrate 31, the frame member 32, and the lid member 33. In addition, illustration of the cover member 33 is abbreviate | omitted in FIG.
As the constituent material of the base substrate 31, those having insulating properties (non-conductive) are preferable. For example, various glass materials, various ceramic materials such as oxide ceramics, nitride ceramics, carbide ceramics, polyimide, etc. Various resin materials can be used.

  In addition, as the constituent material of the frame member 32 and the lid member 33, for example, the same constituent material as that of the base substrate 31, various metal materials such as Al and Cu, various glass materials, and the like can be used. In particular, when a light-transmitting material such as a glass material is used as the constituent material of the lid member 33, vibrations may occur if a metal cover (not shown) is formed on the first piezoelectric substrate 21 in advance. Even after the piece 2 is accommodated in the package 3, the metal cover is irradiated with a laser through the lid member 33 to remove the metal cover and reduce the mass of the first piezoelectric substrate 21. By doing so (by the mass reduction method), the frequency of the resonator element 2 can be adjusted.

  As shown in FIG. 1 or 2, a pair of mount electrodes 34 a and 34 b are formed on the upper surface of the base substrate 31 so as to be exposed to the internal space S. On the mount electrodes 34a and 34b, epoxy-based and polyimide-based conductive adhesives 39a and 39b containing conductive particles are respectively applied (stacked). The above-mentioned vibrating piece 2 is placed on the agents 39a and 39b. Then, by curing the conductive adhesives 39a and 39b, the resonator element 2 is reliably fixed to the mount electrodes 34a and 34b (base substrate 31).

  This fixing is performed by attaching the vibrating piece 2 to the conductive adhesive 39a so that the conductive adhesive 39a contacts the electrode pad 26a of the vibrating piece 2 and the conductive adhesive 39b contacts the electrode pad 26b of the vibrating piece 2. It is carried out by placing on the agents 39a, 39b. As a result, the left end of the resonator element 2 is fixed to the base substrate 31 via the conductive adhesives 39a and 39b, and the electrode pad 26a and the mount electrode 34a, and the electrode pad 26b and the mount electrode 34b are electrically connected. Can be connected. Accordingly, the left end of the resonator element 2 becomes a “fixed end” and the right end becomes a “free end”. The resonator element 2 may be fixed to the base substrate 31 like a CSP (Chip Size Package) structure.

Also, as shown in FIG. 1 or FIG. 2, four external terminals 35a, 35b, 35c, and 35d are provided on the lower surface of the base substrate 31 so as to be positioned at the four corners.
Out of these four external terminals 35a to 35d, the external terminals 35a and 35b are hot connected electrically to the mount electrodes 34a and 34b through conductor posts provided in via holes formed in the base substrate 31, respectively. Terminal. The other two external terminals 35c and 35d are used to increase the bonding strength and equalize the distance between the package 3 and the mounting substrate when the package 3 is mounted on the mounting substrate, respectively. This is a dummy terminal.
Such mount electrodes 34a and 34b and external terminals 35a to 35d can be formed by applying gold plating on a base layer made of tungsten and nickel plating, respectively.

  Note that an electronic component having a function of driving the resonator element 2 may be mounted (mounted) in the internal space S of the package 3. This electronic component is, for example, an integrated circuit element (IC), and is bonded to the upper surface of the base substrate 31 by an insulating (non-conductive) adhesive or an adhesive member such as an adhesive sheet. In this case, a wiring pattern is formed on the upper surface of the base substrate 31 so that the mount electrodes 34a and 34b are energized from the external terminals 35a and 35b through the electronic components. By forming an oscillation circuit in such an electronic component, the piezoelectric device 1 can be configured as a piezoelectric oscillator, or by forming an angular velocity detection circuit, the piezoelectric device 1 can be configured as a piezoelectric gyro. The electronic component may be provided outside the package 3.

  According to the first embodiment as described above, since the resonator element 2 includes the laminated body in which the piezoelectric substrates that undergo thickness-shear vibration are laminated, the first piezoelectric substrate 21 and the second piezoelectric substrate. The displacement amount of the thickness-shear vibration of the entire resonator element 2 can be increased while the voltage applied to each piezoelectric substrate is suppressed by reducing the thickness of each of the piezoelectric elements 22. For this reason, it is possible to efficiently excite the thickness shear vibration while suppressing vibrations other than the thickness shear vibration.

Second Embodiment
Next, a second embodiment of the piezoelectric device of the present invention will be described.
8 is a cross-sectional view of the resonator element included in the piezoelectric device according to the second embodiment of the present invention. FIG. 9 is a second piezoelectric substrate, a second excitation electrode, and a second excitation electrode of the resonator element illustrated in FIG. 3 is a diagram illustrating three excitation electrodes. FIG.

Hereinafter, the piezoelectric device according to the second embodiment will be described focusing on the differences from the above-described embodiment, and description of similar matters will be omitted.
The piezoelectric device of the second embodiment is substantially the same as the first embodiment except that the formation range of the electrode layer (third excitation electrode) between the first piezoelectric substrate and the second piezoelectric substrate is different. It is. In FIG. 8, for convenience of explanation, illustration of the side electrode, the lead electrode, and the electrode pad is omitted. Moreover, the same code | symbol is attached | subjected about the structure similar to embodiment mentioned above.

In the resonator element 2A of the piezoelectric device of the present embodiment, as shown in FIG. 8, the first piezoelectric substrate 21 and the second piezoelectric substrate 22 are joined via an excitation electrode (third excitation electrode) 23d. Has been.
As shown in FIG. 9, the excitation electrode 23d is provided to have a larger area than the excitation electrode 23b of the first embodiment described above. Thereby, the 1st piezoelectric substrate 21 and the 2nd piezoelectric substrate 22 can be joined more firmly via the excitation electrode 23d.

In the present embodiment, the excitation electrode 23d is formed to include the excitation electrodes 23a and 23c when the resonator element 2A is viewed in plan. The length of the excitation electrode 23d in the short direction of the second piezoelectric substrate 22 is equal to the length of the second piezoelectric substrate 22 in the same direction.
In the region of the first piezoelectric substrate 21 sandwiched between the excitation electrode 23a and the excitation electrode 23d (that is, the region where the excitation electrode 23a is formed in a plan view), the thickness shear vibration as described above is excited. The Further, in the region between the excitation electrode 23d and the excitation electrode 23c in the second piezoelectric substrate 22 (that is, the region where the excitation electrode 23c is formed in a plan view), the thickness shear vibration as described above is excited. The

Such an excitation electrode 23d can be easily formed, and positioning with the excitation electrodes 23a and 23c is unnecessary in a plan view. Therefore, the vibration characteristic of the vibrating piece 2A can be easily and reliably made desired.
According to the second embodiment as described above, the thickness shear vibration can be efficiently excited while suppressing vibrations other than the thickness shear vibration.

<Third Embodiment>
Next, a third embodiment of the piezoelectric device of the present invention will be described.
FIG. 10 is a cross-sectional view of the resonator element included in the piezoelectric device according to the third embodiment of the invention.
Hereinafter, the piezoelectric device according to the third embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

  The piezoelectric device of the third embodiment is different from that of the first embodiment except that the formation range of the electrode layer between the first piezoelectric substrate and the second piezoelectric substrate is different and the resonator element has a mesa structure. It is almost the same. The piezoelectric device of the third embodiment is substantially the same as that of the second embodiment except that the resonator element has a mesa structure. In FIG. 10, illustration of the side electrodes and the like is omitted. Moreover, the same code | symbol is attached | subjected about the structure similar to embodiment mentioned above.

As shown in FIG. 10, the resonator element 2B of the piezoelectric device according to the present embodiment includes a first piezoelectric substrate 21B and a second piezoelectric substrate 22B formed to have a mesa structure.
A rectangular convex portion 211B is formed on the upper surface of the first piezoelectric substrate 21B, and a rectangular convex portion 221B is formed on the lower surface of the second piezoelectric substrate 22B. These convex portions 211B and 221B are formed in regions that are rectangular and coincide with each other when the resonator element 2B is viewed in plan.

The first piezoelectric substrate 21B and the second piezoelectric substrate 22B are joined through the excitation electrode 23d.
And the excitation electrode 23a is formed on the convex part 211B, and the excitation electrode 23c is formed on the convex part 221B.
In the present embodiment, when thickness shear vibration is excited in the first piezoelectric substrate 21B and the second piezoelectric substrate 22B, the vibration is confined inside the convex portions 211B and 221B (mesa structure). Therefore, the Q value of the thickness shear vibration can be increased, and as a result, the CI value can be increased.
According to the third embodiment as described above, the thickness shear vibration can be efficiently excited while suppressing vibrations other than the thickness shear vibration.

<Fourth embodiment>
Next, a fourth embodiment of the piezoelectric device of the present invention will be described.
FIG. 11 is a cross-sectional view of the resonator element included in the piezoelectric device according to the fourth embodiment of the invention.
Hereinafter, the piezoelectric device according to the fourth embodiment will be described focusing on the differences from the above-described embodiment, and description of similar matters will be omitted.

  The piezoelectric device of the fourth embodiment is different from that of the first embodiment except that the formation range of the electrode layer between the first piezoelectric substrate and the second piezoelectric substrate is different and the resonator element has an inverted mesa structure. Is almost the same. The piezoelectric device of the fourth embodiment is substantially the same as that of the second embodiment except that the resonator element has an inverted mesa structure. In FIG. 11, illustration of side electrodes and the like is omitted. Moreover, the same code | symbol is attached | subjected about the structure similar to embodiment mentioned above.

As shown in FIG. 11, the resonator element 2 </ b> C of the piezoelectric device of the present embodiment includes a first piezoelectric substrate 21 </ b> C and a second piezoelectric substrate 22 </ b> C formed to have an inverted mesa structure.
A rectangular recess 211C is formed on the upper surface of the first piezoelectric substrate 21C, and a rectangular recess 221C is formed on the lower surface of the second piezoelectric substrate 22C. The concave portions 211C and 221C are formed in regions that are rectangular and coincide with each other when the vibrating piece 2C is viewed in plan.

The first piezoelectric substrate 21C and the second piezoelectric substrate 22C are joined through the excitation electrode 23d.
An excitation electrode 23a is formed on the recess 211C (on the bottom surface), and an excitation electrode 23c is formed on the recess 221C (on the bottom surface).
In the present embodiment, when thickness shear vibration is excited in the first piezoelectric substrate 21C and the second piezoelectric substrate 22C, the vibration is confined inside the recesses 211C and 221C (reverse mesa structure). Therefore, the Q value of the thickness shear vibration can be increased, and as a result, the CI value can be increased.
According to the fourth embodiment as described above, the thickness shear vibration can be efficiently excited while suppressing vibrations other than the thickness shear vibration.

<Fifth Embodiment>
Next, a fifth embodiment of the piezoelectric device of the present invention will be described.
FIG. 12 is a cross-sectional view of the resonator element included in the piezoelectric device according to the fifth embodiment of the invention.
Hereinafter, the piezoelectric device according to the fifth embodiment will be described focusing on the differences from the above-described embodiments, and description of similar matters will be omitted.

The piezoelectric device of the fifth embodiment is substantially the same as that of the first embodiment except that a pair of electrode layers and an insulating layer are provided between the first piezoelectric substrate and the second piezoelectric substrate. In FIG. 12, illustration of side electrodes and the like is omitted. Moreover, the same code | symbol is attached | subjected about the structure similar to embodiment mentioned above.
As shown in FIG. 12, the resonator element 2 </ b> D of the piezoelectric device according to the present embodiment includes an excitation electrode (second excitation electrode) 23 e formed on the lower surface of the first piezoelectric substrate 21, and a second piezoelectric substrate. 22 has an excitation electrode (second excitation electrode) 23f formed on the upper surface of the insulating layer 22 and a bonding layer 28 provided between the excitation electrode 23e and the excitation electrode 23f.

  In the present embodiment, the excitation electrodes 23e and 23f are formed to include the excitation electrodes 23a and 23c when the resonator element 2D is viewed in plan. In the region of the first piezoelectric substrate 21 sandwiched between the excitation electrode 23a and the excitation electrode 23e (that is, the region where the excitation electrode 23a is formed in plan view), the thickness shear vibration as described above is excited. The Further, in the region of the second piezoelectric substrate 22 sandwiched between the excitation electrode 23f and the excitation electrode 23c (that is, the region where the excitation electrode 23c is formed in a plan view), the thickness shear vibration as described above is excited. The

Here, the excitation electrode 23 e and the excitation electrode 23 f are joined via the joining layer 28. The excitation electrode 23e and the excitation electrode 23f are configured to have opposite polarities.
The constituent material of the bonding layer 28 is not particularly limited as long as it can join the excitation electrode 23e and the excitation electrode 23f, and may be a conductive material or an insulating material. An agent, an adhesive, or the like can be used.

The thickness of the bonding layer 28 is not particularly limited, but is preferably as thin as possible in order to reduce the loss of thickness-shear vibration between the first piezoelectric substrate 21 and the second piezoelectric substrate 22. .
According to the fifth embodiment as described above, the thickness shear vibration can be efficiently excited while suppressing vibrations other than the thickness shear vibration.

<Sixth Embodiment>
Next, a sixth embodiment of the piezoelectric device of the present invention will be described.
FIG. 13 is a cross-sectional view of a resonator element included in a piezoelectric device according to a sixth embodiment of the present invention.
Hereinafter, the piezoelectric device according to the sixth embodiment will be described focusing on differences from the above-described embodiment, and description of similar matters will be omitted.

The piezoelectric device of the sixth embodiment is substantially the same as that of the first embodiment except that a third piezoelectric substrate and an electrode layer (fourth excitation electrode) corresponding to the third piezoelectric substrate are provided. In FIG. 13, illustration of side electrodes and the like is omitted. Moreover, the same code | symbol is attached | subjected about the structure similar to embodiment mentioned above.
As shown in FIG. 13, the resonator element 2 </ b> E of the piezoelectric device of the present embodiment is a third piezoelectric substrate bonded to the surface of the second piezoelectric substrate 22 opposite to the first piezoelectric substrate 21. 29.

An excitation electrode (second excitation electrode) 23g is formed on the upper surface of the third piezoelectric substrate 29, and the third piezoelectric substrate 29 is connected to the second piezoelectric substrate 22 via the excitation electrode 23g. It is joined to.
An excitation electrode (third excitation electrode) 23 h is provided on the lower surface of the third piezoelectric substrate 29. The excitation electrode 23h is formed in a region that coincides with the excitation electrode 23a when the resonator element 2E is viewed in plan.

In the present embodiment, the third piezoelectric substrate 29 is subjected to thickness shear vibration in the same direction as the first piezoelectric substrate 21 and the second piezoelectric substrate 22 by applying a voltage between the excitation electrodes 23g and 23h. To do.
Thereby, it is possible to further suppress the voltage applied to each piezoelectric substrate by further suppressing the thickness of each piezoelectric substrate, or to increase the displacement amount of the thickness shear vibration of the entire resonator element 2E. Therefore, thickness shear vibration can be efficiently excited while suppressing vibrations other than thickness shear vibration.

Here, the excitation electrode 23a and the excitation electrode 23g are electrically connected via a side electrode (first side electrode) (not shown), and the excitation electrode 23d is connected via a side electrode (second side electrode) (not shown). Are electrically connected to the excitation electrode 23h. As a result, when a voltage is applied between the two side electrodes, the three piezoelectric substrates can be subjected to thickness-slip vibration in the same direction (in-phase) as described above.
When the vibrating piece 2E is formed using three piezoelectric substrates in this way, an AT plate that vibrates in thickness-shear at 3F [Hz] when the thickness-shear vibration frequency of the vibrating piece 2E is F [Hz]. Three sheets may be used.
According to the sixth embodiment as described above, the thickness shear vibration can be efficiently excited while suppressing vibrations other than the thickness shear vibration.

The piezoelectric device as described above can be applied to various types of electronic equipment, and the obtained electronic equipment has high reliability.
The electronic apparatus including the piezoelectric device (piezoelectric vibrator) and the piezoelectric device with electronic parts of the present invention is not particularly limited. For example, a personal computer (mobile personal computer), a mobile phone, a digital still camera, and an ink jet type ejection device. (For example, inkjet printers), laptop personal computers, televisions, video cameras, video tape recorders, car navigation devices, pagers, electronic notebooks (including those with communication functions), electronic dictionaries, calculators, electronic game devices, word processors, workstations , TV phone, crime prevention TV monitor, electronic binoculars, POS terminal, medical equipment (eg, electronic thermometer, blood pressure monitor, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic endoscope), fish finder, various Constant devices, gauges (e.g., gages for vehicles, aircraft, and ships), a flight simulator, and the like.
As described above, the resonator element, the vibrator, and the piezoelectric device of the present invention have been described based on the illustrated embodiment, but the present invention is not limited to these.

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric device 2 ... Vibrating piece 2A ... Vibrating piece 2B ... Vibrating piece 2C ... Vibrating piece 2D ... Vibrating piece 2E ... Vibrating piece 3 ... Package 21 ... 1st piezoelectric substrate 21B ... 1st piezoelectric substrate 21C ... 1st 1 piezoelectric substrate 22 ... 2nd piezoelectric substrate 22B ... 2nd piezoelectric substrate 22C ... pressure 2nd electric substrate 23a ... excitation electrode 23b ... excitation electrode 23c ... excitation electrode 23d ... excitation electrode 23e ... excitation electrode 23f ... Excitation electrode 23g ... Excitation electrode 23h ... Excitation electrode 24a ... Connection electrode 24b ... Connection electrode 24c ... Connection electrode 25a ... Side electrode 25b ... Side electrode 26a ... Electrode pad 26b ... Electrode pad 27 ... Spacer layer 28 ... Junction layer 29 ... Third piezoelectric substrate 31 ... Base substrate 32 ... Frame member 33 ... Lid member 34a ... Mount electrode 34b ... Mount electrode 35a ... External terminal 35b ... External terminal 35c ... External terminal 35d ... External terminal 39a ... Conductive adhesive 39b ... Conductive adhesive 100 ... AT plate 100a ... AT plate 100b ... AT plate 101a ... Upper surface 101b ... Upper surface 102 ... Lower surface 211B ... Convex part 211C ... Concave part 221B ... Convex part 221C ... Concave part S ... Internal space

Claims (13)

A first substrate for exciting thickness shear vibration;
A second substrate laminated on the first substrate and exciting thickness shear vibration;
A first excitation electrode disposed on a main surface of the first substrate opposite to the second substrate;
A second excitation electrode disposed on a main surface of the second substrate opposite to the first substrate;
A third excitation electrode disposed between the first substrate and the second substrate;
A first side electrode disposed on a side surface of the first substrate and the second substrate and electrically connecting the first excitation electrode and the second excitation electrode;
A second side electrode disposed on a side surface of at least one of the first substrate and the second substrate and electrically connected to the third excitation electrode;
A vibrating piece comprising:   2. The resonator element according to claim 1, wherein each of the first substrate and the second substrate is a piezoelectric substrate made of a piezoelectric material.   The resonator element according to claim 2, wherein the first substrate and the second substrate are bonded to each other via the third excitation electrode.   The resonator element according to claim 3, further comprising a spacer layer that is spaced apart from the third excitation electrode and is disposed between the first substrate and the second substrate in the vicinity of the first side electrode. . A first extraction electrode disposed on a main surface of the first substrate opposite to the second substrate and extending from the first excitation electrode toward a side surface of the first substrate; When,
A second extraction electrode disposed on a main surface of the second substrate opposite to the first substrate and extending from the second excitation electrode toward a side surface of the second substrate; When,
With
5. The resonator element according to claim 2, wherein the first extraction electrode and the second extraction electrode are electrically connected to each other via the first side electrode. A third drawer disposed between the first substrate and the second substrate and extending from the third excitation electrode toward a side surface of the first substrate or the second substrate; With electrodes,
The resonator element according to claim 5, wherein the third lead electrode is electrically connected to the second side electrode. On the main surface of the first substrate or the second substrate opposite to the third excitation electrode,
A first electrode pad electrically connected to the first side electrode;
A second electrode pad electrically connected to the second side electrode;
The resonator element according to claim 6, wherein   The resonator element according to claim 2, wherein each of the first substrate and the second substrate is a quartz substrate.   The resonator element according to claim 8, wherein the quartz substrate is a quartz rotating Y plate.   10. The resonator element according to claim 9, wherein the crystal rotation Y plate is any one of an AT cut crystal substrate, a BT cut crystal substrate, and an SC cut crystal substrate. The first substrate and the second substrate are quartz substrates having the same cut angle,
The resonator element according to claim 10, wherein the crystal axis of one crystal substrate is in the same direction as a crystal axis obtained by rotating the other crystal substrate by 180 ° about the Y ′ axis or the Z ′ axis. A resonator element according to any one of claims 1 to 11,
A package for storing the resonator element;
A vibrator comprising:   A piezoelectric device comprising the vibrator according to claim 12.

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