JP2011239256A - Vibration chip, vibrator, oscillator and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration chip with a warp of a vibration arm being suppressed, a vibrator and an oscillator using the vibration chip or an electronic device using the vibration chip.SOLUTION: A vibration chip 1 has a base 16 formed by processing a Z cut quartz plate and three vibration arms 18a, 18b and 18c extending from one end of the base 16 in parallel with one another. On a first surface 12 of each vibration arm 18a 18b and 18c, a first laminate is formed by laminating a first electrode layer 20, a first piezoelectric-body layers 22 and a second electrode layer 26 in this order as an excitation electrode. In addition, on a second surface 10 of the each vibration arm 18a 18b and 18c, a second laminate formed by laminating a metal layer 5 and a second piezoelectric-body layers 7, which are electrically independent of each other, in this order is disposed. For example, Pt, Ti, Ti-Au alloy or the like can be used to form the first electrode layer 20. Further, for example, Al, Cr, Ni or the like can be used to form the metal layer 5.

Description

  The present invention relates to a resonator element, a vibrator using the same, an oscillator using the same, and an electronic device using the same.

  Conventionally, as a flexural vibration piece that vibrates in a flexural vibration mode, for example, a pair of vibration arms are extended in parallel with each other from a base portion made of a base material for a vibration body such as a piezoelectric material, and along the main surfaces of the vibration arms. In addition, tuning fork-type vibrating pieces that vibrate in the direction toward or away from each other in the horizontal direction are widely used. In addition, a type of tuning fork type resonator element in which the vibrating arm is bent and vibrated in a direction orthogonal to the main surface of the vibrating arm has been introduced (see, for example, Patent Document 1). When the vibration arms of these vibrating pieces are excited to bend and vibrate, if the vibration energy is lost, the cause is a decrease in the performance of the vibrating piece, such as an increase in CI (Crystal Impedance) value or a decrease in Q value. Become. Therefore, various ideas have been conventionally made in order to prevent or reduce such loss of vibration energy.

  For example, Patent Literature 2 introduces a tuning fork type vibration piece (piezoelectric vibration piece) in which a groove is formed on the center line in the extending direction of a vibration arm having a rectangular cross section. The vibration piece described in Patent Literature 2 includes a base portion and a pair of vibration arms that are divided into two branches from one end portion of the base portion and extend in parallel. On the front surface (first surface) and the back surface (second surface) of the vibration arm, elongated grooves extending in the extending direction of the vibration arm are provided. An electrode layer (metal film) as an excitation electrode of the resonator element is formed on the surface of the groove. As described above, by forming the groove in the vibration arm, the vibration arm easily vibrates, the vibration efficiency is improved, and the increase in the CI value can be suppressed.

  In recent years, electronic devices such as mobile phones, mobile computers, personal digital assistants (PDAs), and small communication devices such as GPS (Global Positioning System) have been increasingly requested to be smaller and thinner. Yes. Along with this, there is an increasing demand for smaller and thinner vibrators and oscillators using the resonator element used in these electronic devices. As described above, when the vibration piece is reduced in size and thickness, when the groove portion is formed in the vibration arm as in the vibration piece described in Patent Document 1, the rigidity is lowered, and the vibration piece is deformed by handling in the manufacturing process of the vibration piece. There is a risk of increasing the possibility of occurrence of damage.

  The inventor reduced the loss of vibration energy by reducing the thickness of the vibrating arm and improving the vibration efficiency in a vibrating piece of the type in which no groove is provided in the vibrating arm, and the thickness of the base portion than the vibrating arm. It has been found that the rigidity of the resonator element can be maintained by increasing the thickness.

JP 2005-197946 A JP 2009-60478 A

  However, in the resonator element having a base thicker than the vibration arm, a drive electrode made of a stacked body in which the first electrode layer, the piezoelectric layer, and the second electrode layer are stacked in this order is provided on the first surface of the vibration arm. In this case, the vibration arm is warped against the second surface side, which is the back surface of the first surface, with respect to the base part due to the influence of stress mainly due to the orientation of the piezoelectric layer, and it is difficult to perform exposure by a photo process. Therefore, there is a problem that the electrode wiring is likely to be disconnected, and the characteristics such as electric resistance are deteriorated and the vibration characteristics may be unstable.

  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 A resonator element according to this application example includes a base, a vibration arm extending from one end of the base, and a drive electrode formed on the first surface of the vibration arm. The drive electrode includes a first electrode layer formed on the first surface, a first piezoelectric layer provided on the first electrode layer, and the first electrode layer sandwiching the first piezoelectric layer. A second electrode layer provided opposite to the second electrode layer, and an electrically independent metal layer on the second surface in a front-back relationship with the first surface, and on the metal layer A second laminated body including a second piezoelectric layer provided on the substrate is formed.

  According to this configuration, when only the first stacked body that forms the drive electrode of the resonator element is provided, the warp of the vibrating arm caused by the stress acting on the first stacked body is reduced. This can be improved by the stress acting on the second laminate provided on the surface. In particular, it is effective against the warp of the vibrating arm that becomes noticeable as the vibrating piece becomes smaller and thinner, which is advantageous for making the vibrating piece smaller and thinner.

  Application Example 2 In the resonator element according to the application example described above, the first electrode layer and the metal layer have different metal compositions.

  According to this configuration, since the orientation of the first piezoelectric layer formed on the first electrode and the orientation of the second piezoelectric layer formed on the metal layer can be changed, for example, the second piezoelectric body By controlling the orientation of the layer, it is possible to reduce the amount of warping of the vibrating arm.

  Application Example 3 In the resonator element according to the application example, at least one of the first electrode layer and the metal layer has a laminated structure, and the layer configuration of the first electrode layer and the metal layer is different. It is characterized by.

  According to this configuration, since the orientation of the first piezoelectric layer and the orientation of the second piezoelectric layer can be changed, the orientation of the second piezoelectric layer can be controlled to reduce the amount of warp of the vibration arm. Is possible.

  Application Example 4 In the resonator element according to the application example, the base portion and the vibration arm are formed using a piezoelectric material.

  According to this configuration, by using a piezoelectric material that has been widely used as a material for a resonator element, a high-performance piezoelectric resonator element that uses the piezoelectric effect in consideration of known principles and know-how is provided. be able to.

  Application Example 5 In the resonator element according to the application example, crystal is used as the piezoelectric material.

  According to this configuration, by using quartz, it is possible to suppress a decrease in temperature characteristics (temperature dependence such as frequency characteristics) associated with downsizing of the resonator element.

  Application Example 6 A vibration piece according to this application example includes a base, a vibration arm extending from one end of the base, and a drive electrode formed on the first surface of the vibration arm. The drive electrode includes a first electrode layer formed on the first surface, a first piezoelectric layer provided on the first electrode layer, and the first electrode layer sandwiching the first piezoelectric layer. A second electrode layer provided opposite to the first electrode layer, wherein a second piezoelectric layer is formed on a second surface which is the back surface of the first surface.

  According to this configuration, similarly to the above application example, the warp of the vibrating arm can be improved by the stress acting on the second piezoelectric layer provided on the second surface of the vibrating arm. In addition, since nothing is provided below the second piezoelectric layer, it is possible to reduce the number of manufacturing steps of the resonator element as compared with the application example.

  Application Example 7 A vibrator according to this application example includes the resonator element according to the application example and a package that accommodates the resonator element.

  According to this configuration, since the vibration piece in which the warp of the vibration arm shown in the application example is reduced is provided, a small vibrator having stable vibration characteristics can be provided.

  Application Example 8 An oscillator according to this application example includes a resonator element, a circuit element including an oscillation circuit that oscillates the resonator element, and a package that accommodates the resonator element and the circuit element. To do.

  According to this configuration, since the vibration piece in which the warp of the vibration arm shown in the application example is suppressed is provided, a small oscillator having a small and stable oscillation characteristic can be provided.

  Application Example 9 An electronic apparatus according to this application example includes the vibrator according to the application example or the oscillator according to the application example.

  According to this configuration, since the resonator having the stable vibration characteristics according to the application example or the oscillator having the stable oscillation characteristics according to the application example is mounted, the structure is small and has excellent characteristics. Provided electronic equipment can be provided.

(A) is a schematic plan view explaining one embodiment of the resonator element when viewed from the upper side (first surface side), (b) is a schematic plan view when viewed from the bottom side (second surface side), (c) ) Is a cross-sectional view taken along line AA ′ of FIGS. (A)-(c) is a schematic plan view which shows the process of electrode formation of a vibration piece. (A) is a schematic plan view explaining one Embodiment of the vibrator | oscillator using the resonator element of this invention, (b) is the BB 'sectional view taken on the line of (a). (A) is a schematic plan view explaining one Embodiment of the oscillator using the resonator element of this invention, (b) is CC 'sectional view taken on the line of (a). FIG. 9 is a schematic cross-sectional view illustrating one variation of Modification Example 1 of the resonator element. FIG. 6 is a schematic cross-sectional view illustrating another variation of the first modification of the resonator element. FIG. 9 is a schematic cross-sectional view illustrating a second modification of the resonator element. (A) is a figure which shows the mobile telephone as an electronic device carrying the vibrator | oscillator and oscillator of this invention, (b) is a figure which similarly shows the mobile computer as an electronic device.

  Hereinafter, an embodiment of a resonator element according to the invention will be described with reference to the drawings.

(First embodiment)
1A and 1B illustrate an embodiment of a resonator element. FIG. 1A is a schematic plan view viewed from the upper side (first surface side), and FIG. 1B is a schematic plan view viewed from the back side (second surface side). (C) is the sectional view on the AA 'line of (a) and (b). 2A to 2C are schematic plan views for explaining the process of forming the electrodes of the resonator element.

[Vibration piece]
In FIG. 1, the resonator element 1 according to the present embodiment includes a base portion 16 formed by processing a resonator element forming material, and three base portions extending in parallel from one end side (the upper end side in the drawing) of the base portion 16. The vibrating arms 18a, 18b, and 18c are formed.
As a material for forming the resonator element 1, for example, a piezoelectric material can be used. In the present embodiment, a material cut out from a single crystal of quartz that has been widely used as a piezoelectric vibrating piece forming material is used. For example, from a so-called Z-cut crystal thin plate, the Y axis of the crystal crystal axis is in the extending direction of the vibrating arms 18a, 18b, 18c, the X axis is in the width direction orthogonal to the extending direction, and the Z axis is in the vibrating piece. The first surface 12 and the second surface 10 as the front and back main surfaces are formed so as to be oriented in the vertical direction.

  As shown in FIG. 1C, the substantially rectangular base 16 in plan view has a thickness that is thicker than the vibrating arms 18a, 18b, and 18c. More specifically, the first surface 12 of the base portion 16 and the vibrating arms 18a, 18b, and 18c are the same plane, and the second surface 10 side of the resonator element 1 is thick at the base portion 16 and is vibrated by the vibrating arms 18a, 18b, and 18c. Thinly formed. In this way, in the manufacturing process of the resonator element 1 that is made smaller and thinner by making the base portion 16 thicker than the vibrating arms 18a, 18b, and 18c that are the vibrating portions of the resonator element 1, the rigidity is increased. It is possible to avoid problems such as damage during handling.

The external shape of such a vibrating piece 1 can be precisely formed, for example, by wet etching or dry etching a quartz substrate material (quartz wafer) with a hydrofluoric acid solution or the like using photolithography. .
Note that, in the resonator element 1 of the present embodiment, the inclined surface 14 is formed on the second surface 10 extending from the connection portion between the base portion 16 and each of the vibration arms 18a, 18b, and 18c. The inclined surface 14 is formed by etching anisotropy of the Z-cut crystal when the Z-cut crystal thin plate is wet-etched to form the outer shape of the resonator element 1. For example, an X-cut crystal is used. In such a case, a substantially vertical side wall is formed on the second surface 10 extending from the connecting portion between the base portion 16 and the vibrating arms 18a, 18b, 18c.

Note that a piezoelectric material other than the above-described quartz can be used as the vibrating piece forming material. For example, oxide substrates such as aluminum nitride (AlN), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), lead zirconate titanate (PZT), and lithium tetraborate (Li ₂ B ₄ O ₇ ) A piezoelectric substrate formed by laminating a thin film piezoelectric material such as aluminum nitride or tantalum pentoxide (Ta ₂ O ₅ ) on a glass substrate can be used.
In addition to the piezoelectric material, the resonator element can be formed of, for example, a silicon semiconductor material.
However, the resonance frequency of the bending vibration piece is proportional to the square root of the value obtained by dividing the Young's modulus of the bending vibration material by the mass density, and the smaller the value obtained by dividing the Young's modulus by the mass density, the more the vibration piece of the bending vibration mode. It is advantageous for downsizing. Therefore, the bending vibration piece made of crystal like the vibration piece 1 of the present embodiment is advantageous for miniaturization because the square root of the value obtained by dividing the Young's modulus by the mass density can be reduced as compared with a silicon semiconductor material or the like. Since the frequency temperature characteristics are excellent, the material used for the resonator element 1 is particularly preferable.

Excitation electrodes are formed on the first surface 12 of each vibration arm 18a, 18b, 18c. The excitation electrode of the resonator element 1 according to this embodiment includes a first stacked body in which a first electrode layer 20, a first piezoelectric layer 22, and a second electrode layer 26 are stacked in this order (each electrode Details of the layer and the piezoelectric layer will be described later).
In addition, the excitation electrode formed on each vibration arm is drawn out to the base 16 and connected to external connection electrodes 26 a and 26 b provided for connection to the outside provided on the base 16. In the present embodiment, of the three vibrating arms, the first electrode layer 20 formed on the vibrating arms 18 a and 18 c at both ends and drawn out to the base 16, and the first electrode layer 20 formed on the central vibrating arm 18 b and drawn out to the base 16. The first electrode layer 20 thus formed and the second electrode layer 26 electrically connected by two openings 24 (corresponding to the external connection electrodes 26a and 26b) formed in the first piezoelectric layer 22 on the base portion 16, respectively. Thus, the external connection electrodes 26a and 26b are formed.

Here, in order to make it easy to understand the structure of the first laminate as the excitation electrode of the resonator element 1 formed on the first surface 12 of the vibration arms 18a, 18b, and 18c, the electrodes constituting the first laminate. The process of forming the layer and the piezoelectric layer will be described.
As shown in FIG. 2A, first, the first electrode layer 20 is formed on the first surface 12 of the vibrating arms 18a, 18b, 18c. In the present embodiment, the first electrode layer 20 has a length in the extending direction of each vibration arm 18a, 18b, 18c from the base to the base 16 of the vibration arms 18a, 18b, 18c toward the tip side. In addition to being formed up to a part, in order to make an electrical connection with the external connection electrodes 26a and 26b to be formed on the base 16 later, a lead-out wiring is formed on the base 16 and formed.

  Next, as shown in FIG. 2B, the first piezoelectric layer 22 is formed so as to cover the first electrode layer 20 and a part of the base portion 16, and the first electrode is formed on the first piezoelectric layer 22. An opening 24 for electrically connecting the layer 20 and a second electrode layer 26 to be formed later is formed.

Next, as shown in FIG. 2C, the second electrode layer 26 is formed on the first piezoelectric layer 22. In this step, the first electrode layer 20 of the vibration arms 18a and 18c and the second electrode layer 26 of the vibration arm 18b are connected through one opening 24 of the first piezoelectric layer 22, and the vibration arms 18a and 18c. The second electrode layer 26 and the first electrode layer 20 of the vibrating arm 18 b are connected via the other opening 24 of the first piezoelectric layer 22, and each is drawn out from the second electrode layer 26 onto the base 16. Are connected to corresponding external connection electrodes 26a and 26b.
Through the above steps, the first laminate as the excitation electrode formed by laminating the first electrode layer 20, the first piezoelectric layer 22, and the second electrode layer 26 is formed on the resonator element 1.

  As shown in FIG. 1C, on the second surface 10 that is in a front-back relationship with the first surface 12 of the vibrating arms 18a, 18b, and 18c on which the first laminate is formed through the steps described above, A second laminated body in which the metal layer 5 and the second piezoelectric layer 7 are laminated in this order is provided. In the present embodiment, the second stacked body is provided in a region that overlaps the first stacked body in plan view in the vibrating arms 18a, 18b, and 18c. In the second laminate, the metal layer 5 is not connected to the electric circuit formed on the resonator element 1 and is electrically independent.

[Materials for forming each electrode layer, metal layer, and piezoelectric layer]
Here, materials for forming each electrode layer, metal layer, or piezoelectric layer of the resonator element 1 of the present embodiment will be described.
First, the first piezoelectric body layer 22 of the first laminate formed on the first surface 12 of the vibration arms 18 a, 18 b, 18 c of the resonator element 1, and the second laminate formed on the second surface 10. The second piezoelectric layer 7 is formed using a piezoelectric material such as AlN (aluminum nitride) or ZnO (zinc oxide).

For example, Pt (platinum), Ti (titanium), or Ti—Au (titanium—) is used as the first electrode layer 20 formed on the first surface 12 of the resonator element 1 as a base layer of the first piezoelectric layer 22. Gold) alloy or the like can be used. By providing the first electrode layer 20 with such a metal or alloy, the orientation of the first piezoelectric layer 22 laminated on the first electrode layer 20 can be improved.
In addition, as a material used for the second electrode layer 26 laminated on the first piezoelectric layer 22, Pt, Ti, or Ti—Au alloy used for the first electrode layer 20 may be used. Other electrode forming metals such as Al (aluminum), Cr (chromium), Ni (nickel), and alloys can be used.

On the other hand, for the metal layer 5 formed on the second surface 10 of the resonator element 1 as the base layer of the second piezoelectric layer 7, for example, Al, Cr, Ni, or the like can be used. By forming the metal layer 5 using such a metal material, the orientation of the second piezoelectric layer 7 laminated on the metal layer 5 is more than the orientation of the first piezoelectric layer 22. Go down.
As described above, the material for forming the first electrode layer 20 that is the base layer of the first piezoelectric layer 22 on the first surface 12 side, and the metal that is the base layer of the second piezoelectric layer 7 on the second surface 10 side. By forming the formation material of the layer 5 using a different metal material, the orientation of the first piezoelectric layer 22 and the second piezoelectric layer 7 to be laminated on each other is changed, whereby each vibration arm 18a. , 18b, and 18c, the warp generated in the vibrating arms 18a, 18b, and 18c can be suppressed as compared with the vibrating piece having the conventional structure in which the second stacked body is not formed on the second surface 10. Thus, the vibration piece 1 having stable vibration characteristics can be provided by suppressing the warp of the vibration arms 18a, 18b, and 18c.

When the first piezoelectric layer 22 and the second piezoelectric layer 7 are formed of the same piezoelectric material, the first piezoelectric layer 22 described with reference to FIG. Two piezoelectric layers 7 can be formed simultaneously.
Further, when the metal material used for the metal layer 5 formed on the second surface 10 of the vibrating arms 18a, 18b, 18c is the same as the material used for the first electrode layer 20 formed on the first surface 12, FIG. In the step of forming the first electrode layer 20 described in 2 (a), the metal layer 5 can be formed simultaneously.
As described above, the electrode layer, the metal layer, or the piezoelectric layer formed on the first surface 12 and the second surface 10 of the vibrating arms 18a, 18b, and 18c, respectively, can be manufactured with fewer manufacturing steps by considering the combination of materials used. Can be formed efficiently.

(Second Embodiment)
[Vibrator]
Next, a vibrator using the vibrating piece 1 will be described.
FIGS. 3A and 3B are diagrams for explaining an embodiment of a vibrator using the resonator element 1, wherein FIG. 3A is a schematic plan view seen from the upper side, and FIG. FIG. 3A illustrates a state in which the lid 91 (see FIG. 3B) provided above the vibrator 500 is removed for convenience of describing the internal structure of the vibrator.

  In FIG. 3, the vibrator 500 includes a package 70 provided with a recess having a step. The resonator element 1 is joined to the concave bottom portion of the concave portion of the package 70, and a lid 91 as a lid is joined to the open upper end of the package 70.

  The package 70 is formed by laminating a rectangular annular second layer substrate 72 and a third layer substrate 73 having different opening sizes on a flat plate-like first layer substrate 71 in this order. A recess having an opening and a step in the interior is formed. As a material of the package 70, for example, ceramic, glass, or the like can be used.

  In the recess of the package 70, a plurality of vibration piece connection terminals 76 to which the vibration piece 1 is bonded are provided on the step formed by the second layer substrate 72. In addition, an external mounting terminal 75 used for bonding to an external substrate or the like is provided on the surface opposite to the concave surface of the first layer substrate 71 which is the outer bottom surface of the package 70. In this way, the various terminals provided in the package 70 are connected to each other by inter-layer wiring such as routing wiring and through-hole (not shown).

  The resonator element 1 is bonded to the recess of the package 70. In the present embodiment, the resonator element provided on the step formed by the second layer substrate 72 of the package 70 on the surface opposite to the surface on which the external connection electrodes 26 a and 26 b of the base portion 16 of the resonator element 1 are formed. It is bonded and fixed in the vicinity of the connection terminal 76 via a bonding member 99 such as an adhesive, and the external connection electrodes 26a and 26b of the vibration piece 1 and the corresponding vibration piece connection terminal 76 of the package 70 are bonded to the bonding wire. 95 is electrically connected. As a result, the resonator element 1 is cantilevered with the vibration arms 18 a, 18 b, and 18 c as free ends while leaving a gap between the resonator element 1 and the first layer substrate 71 that forms the concave bottom portion of the recess in the package 70. Fixed in a manner.

  As shown in FIG. 3B, a lid 91 as a lid is disposed on the upper end of the package 70 in which the resonator element 1 is joined in the recess, and the opening of the package 70 is sealed. As the material of the lid 91, for example, a metal such as 42 alloy (an alloy containing 42% nickel in iron) or Kovar (an alloy of iron, nickel and cobalt), ceramics, glass, or the like can be used. When the lid 91 made of metal is used, for example, it can be joined to the package 70 by seam welding via a seal ring 79 formed by punching a Kovar alloy or the like into a rectangular ring shape. An internal space formed in the package 70 by joining the lid 91 becomes a space for the vibration piece 1 to operate. The internal space can be sealed and sealed in a reduced pressure space or an inert gas atmosphere.

  According to the vibrator 500 having the above-described configuration, as described above, the resonator element 1 in which the warp of the vibration arms 18a, 18b, and 18c is suppressed by the second stacked body is provided, and thus a small size having stable vibration characteristics. Can be provided.

(Third embodiment)
[Oscillator]
Next, an oscillator using the vibrating piece 1 will be described.
4A and 4B illustrate an embodiment of an oscillator on which the resonator element 1 is mounted. FIG. 4A is a schematic plan view seen from above, and FIG. 4B is a cross-sectional view taken along the line CC 'in FIG. It is. 4A shows a state in which the lid 92 provided above the oscillator 600 is removed for convenience of explaining the internal structure of the oscillator.

  In FIG. 4, the oscillator 600 includes a package 80 provided with a recess having a step. An IC chip 60 as a circuit element and the resonator element 1 disposed above the IC chip 60 are joined to the concave bottom portion of the concave portion of the package 80, and a lid is formed on the upper end of the package 80 having an opening. The lid 92 is joined.

The package 80 is configured by laminating a rectangular annular second layer substrate 82, a third layer substrate 83, and a fourth layer substrate 84 having different opening sizes on a flat first layer substrate 81 in this order. As a result, a recess having an opening on the upper surface side and having a step inside is formed.
A die pad 86 on which the IC chip 60 is disposed is provided on the first layer substrate 81 which is a concave bottom portion of the concave portion of the package 80. In addition, an external mounting terminal 85 used for bonding to an external substrate or the like is provided on the surface opposite to the surface on which the die pad 86 of the first layer substrate 81 is provided as the outer bottom surface of the package 80.
A plurality of IC connection terminals 87 for electrical connection with the IC chip 60 are provided on the step formed by the second layer substrate 82 in the recess of the package 80. On the step formed by the third layer substrate 83, a plurality of vibrating piece connection terminals 88 to which the vibrating piece 1 is bonded are provided. As described above, the various terminals provided in the package 80 are connected to each other by inter-layer wirings such as routing wirings and through holes (not shown).

  The IC chip 60 is a semiconductor circuit element including an oscillation circuit that oscillates the resonator element 1 and a temperature compensation circuit. The IC chip 60 is bonded and fixed to, for example, a brazing material 98 on a die pad 86 provided on the concave bottom portion of the concave portion of the package 80. Further, in the present embodiment, the IC chip 60 and the package 80 are electrically connected using a wire bonding method. Specifically, the plurality of electrode pads 35 provided on the IC chip 60 and the corresponding IC connection terminals 87 of the package 80 are connected by bonding wires 95.

  In addition, the resonator element 1 is bonded to the concave portion of the package 80 above the IC chip 60. Specifically, the base 16 of the resonator element 1 is bonded to the vicinity of the resonator element connection terminal 88 provided on the step formed by the third layer substrate 83 of the package 80 via a bonding member 99 such as an adhesive. In addition to being fixed, the external connection electrodes 26 a and 26 b of the resonator element 1 and the corresponding resonator element connection terminals 88 of the package 80 are electrically connected by the bonding wire 95. As a result, the resonator element 1 is fixed in a manner that it is cantilevered with the vibration arms 18 a, 18 b, and 18 c as free ends while leaving a gap between the resonator element 1 and the IC chip 60 bonded downward in the package 80. The

  As shown in FIG. 4B, a lid 92 is disposed at the upper end of the package 80 in which the IC chip 60 and the resonator element 1 are joined in the recess, and the package is formed by, for example, seam welding via a seal ring 89. 80. An internal space serving as a space for operating the resonator element 1 in the package 80 can be sealed and sealed in a reduced pressure space or an inert gas atmosphere.

  According to the oscillator 600 configured as described above, since the resonator element 1 in which the warp of the vibration arms 18a, 18b, and 18c is suppressed by the provision of the second stacked body is mounted, the oscillator 600 is small and stable. An oscillator 600 having the above-described oscillation characteristics can be provided.

(Fourth embodiment)
〔Electronics〕
The electronic device in which the vibrator 500 according to the second embodiment including the resonator element 1 according to the first embodiment or the oscillator 600 according to the third embodiment is mounted is reduced in size and performance. It is possible.
For example, as a signal source of the mobile phone 200 as the electronic device shown in FIG. 8A or the mobile computer 300 as the electronic device shown in FIG. 8B, the warp of the vibrating arms 18a, 18b, and 18c is reduced. By mounting the vibrator 500 or the oscillator 600 provided with the small vibrating piece 1, the mobile phone 200 and the mobile computer 300 can be downsized and highly functional.
In addition to these mobile phones 200 and mobile computers 300, in small-sized communication equipment such as a portable information terminal such as a PDA (Personal Digital Assistant) or a global positioning system widely known as GPS (Global Positioning System). In recent years, there has been an increasing demand for miniaturization and thinning. Therefore, a resonator element having a small and stable vibration characteristic, and a vibrator 500 and an oscillator 600 using the resonator element are mounted. It is possible to cope with downsizing of electronic devices and to have stable characteristics.

  The resonator element as the resonator element described in the above embodiment can also be implemented as the following modification.

(Modification 1)
In the above embodiment, in each of the vibrating arms 18a, 18b, and 18c, the metal layer 5 formed on the second surface 10 and the first electrode layer 20 formed on the first surface 12 include the single-layer first electrode layer 20 and The configuration for forming the metal layer 5 has been described. Not limited to this, the first metal layer and the metal layer may have a multilayer structure.
FIG. 5 and FIG. 6 schematically illustrate variations of the modification of the resonator element having a multilayer structure of the metal layer and the first electrode layer, both of which are diagrams of the resonator element 1 of the above embodiment. It is sectional drawing which shows the same cross section as 1 (c). In the description of the first modification of the resonator element illustrated in FIGS. 5 and 6, the same components as those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted.

First, a first variation of the resonator element according to Modification 1 will be described.
In the vibrating arm 108 of the vibrating piece 101 shown in FIG. 5, the first stacked body formed on the first surface 12 is the same as in the above embodiment, the first electrode layer 20 of the single layer, the first piezoelectric layer 22, And the 2nd electrode layer 26 is laminated | stacked and comprised in this order.
On the other hand, the second laminated body formed on the second surface 10 of the vibrating arm 108 has a structure in which a metal layer and a second piezoelectric layer 107 are laminated in this order, and the metal layer is formed on the second surface 10. It has a two-layer structure of the formed underlayer 105 and the upper layer 106 laminated on the underlayer 105.

As a combination of the base layer 105 and the upper layer 106, a metal is used for the upper layer 106 and an insulating layer is formed on the base layer 105, or an insulating layer is formed on the upper layer 106 using metal for the base layer 105. Or a combination using metal for both the upper layer 106 and the base layer 105 can be selected.
In order to increase the orientation of the second piezoelectric layer 107, a SiO ₂ (silicon dioxide) layer may be formed as the base layer 105, and a Ti (titanium) layer, for example, may be formed as the upper layer 106. .
Further, when the orientation of the second piezoelectric layer 107 is lowered, a (silicon dioxide) layer may be formed as the base layer 105 and a SiO ₂ layer may be formed as the upper layer 106.
Thus, the orientation of the first piezoelectric film 22 on the first surface 12 side of the vibrating arm 108 is adjusted by appropriately selecting the combination of the base layer 105 and the upper layer 106 and adjusting the orientation of the second piezoelectric layer 107. Therefore, the warp of the vibrating arm 108 of the vibrating piece 101 can be reduced.

  Further, in the vibration piece 111 of another variation of the first modification shown in FIG. 6, of the second stacked body formed on the second surface 10 of the vibration arm 118, the lower layer of the second piezoelectric layer 117 (first In addition to the metal layer on the second surface 10 side) having a two-layer structure of a base layer 115 formed on the second surface 10 and an upper layer 116 stacked on the base layer 115, Also in the first stacked body formed on the first surface 12 of the vibrating arm 118, a metal layer under the first piezoelectric layer 222 (layer on the first surface 12 side) is formed on the first surface 12. The underlayer 220a and the upper layer 220b laminated on the underlayer 220a have a two-layer structure.

  Also in the first laminated body of the first surface 12 and the second laminated body of the second surface 10 provided on the vibrating arm 118 of the vibrating piece 111, the underlayer 105 and the upper layer 106 in FIG. By selecting a combination similar to the above combination, the orientation of the first piezoelectric layer 222 and the second piezoelectric layer 117 can be adjusted, so that the warp of the vibration arm 118 can be reduced. Become.

(Modification 2)
In the above-described embodiment and Modification 1, out of the second stacked body provided on the second surface 10 of each vibration arm 18a, 18b, 18c, the lower layer (second surface 10) of the second piezoelectric layers 7, 107, 117. The metal layer 5 having a single layer or a metal layer having a two-layer structure of the base layers 105 and 115 and the upper layers 106 and 116 is provided on the side). Not limited to this, the second piezoelectric layer may be directly formed on the second surface of the vibrating arm.
FIG. 7 schematically illustrates a second modification of the resonator element in which the second piezoelectric layer is directly formed on the second surface of the resonator arm. FIG. 7C illustrates the resonator element 1 according to the above embodiment. It is sectional drawing which shows the same cross section. In the description of the modification 2 of the resonator element illustrated in FIG. 7, the same components as those in the above embodiment are denoted by the same reference numerals and the description thereof is omitted.

As shown in FIG. 7, the first electrode layer 20, the first piezoelectric layer 22, and the second electrode layer 26 are formed on the first surface 12 of the vibrating arm 128 of the vibrating piece 121, as in the above embodiment. An excitation electrode made of a first laminated body that is sequentially laminated is formed.
A second piezoelectric layer 127 is formed on the second surface 10 of the vibrating arm 128.
As described above, since the second piezoelectric layer 127 directly laminated on the second surface 10 made of, for example, crystal of the resonator element 121 has low orientation, the first surface formed on the first surface 12 side of the vibrating arm 128 is reduced. The warp of the vibrating arm 128 can be reduced by the difference in the orientation of the first piezoelectric layer 22 of the laminate.
In addition, according to this configuration, nothing is provided in the lower layer (second surface 10 side) of the second piezoelectric layer 127, so that the number of manufacturing steps of the resonator element 121 is less than that in the above embodiment and the first modification. There is an effect.

  The embodiment of the present invention made by the inventor has been specifically described above, but the present invention is not limited to the above-described embodiment, and various modifications are made without departing from the scope of the present invention. Is possible.

  For example, in the above embodiment, the vibration piece 1 having the three vibration arms 18a, 18b, and 18c has been described. The vibration piece of the present invention is not limited to this, and may be a strip-shaped so-called beam-type bending vibration piece, or a so-called tuning-fork type vibration piece having two vibration arms, or four or more vibration arms. Even if it is a vibration piece, the effect by taking the structure similar to above-described embodiment and modification can be acquired.

Further, in the vibrator 500 of the second embodiment and the oscillator 600 of the third embodiment, the resonator element 1 is mechanically joined to the packages 70 and 80 by the joining member 99, and further, a wire bonding method is used. And the resonator element 1 and the packages 70 and 80 are electrically connected by a bonding wire 95. However, the external connection electrodes 26 a and 26 b of the resonator element 1 are provided on the second surface side of the base portion 16, and the external connection electrodes 26 a and 26 b and the corresponding resonator element connection terminals 76 and 88 of the packages 70 and 80 are provided. Can be joined by a conductive joining member such as a silver paste. In this case, mechanical joining and electrical connection of the resonator element 1 to the packages 70 and 80 can be realized at the same time.
In the oscillator 600 of the third embodiment, the configuration in which the IC chip 60 is connected to the package 80 by the bonding wire 95 using the wire bonding method has been described. However, the present invention is not limited to this, and an electronic component such as the IC chip 60 may be face-down bonded using another mounting method, for example, a bonding member such as a metal bump or a conductive adhesive.

  DESCRIPTION OF SYMBOLS 1,101,111,121 ... Vibration piece, 5 ... Metal layer, 7, 107, 117 ... 2nd piezoelectric material layer, 10 ... 2nd surface, 12 ... 1st surface, 14 ... Inclined surface, 16 ... Base part, 18a 18c, 108, 118, 128 ... vibrating arm, 20 ... first electrode layer, 22, 222 ... first piezoelectric layer, 24 ... opening, 26 ... second electrode layer, 26a, 26b ... external connection electrode, 35 ... Electrode pads, 60 ... IC chips as circuit elements, 70, 80 ... Packages, 71, 81 ... First layer substrates, 72,82 ... Second layer substrates, 73,83 ... Third layer substrates, 75 ... External mounting Terminals 76, 88 ... Vibrating piece connection terminals, 79, 89 ... Seal ring, 84 ... Fourth layer substrate, 86 ... Die pad, 87 ... IC connection terminal, 91, 92 ... Lid, 95 ... Bonding wire, 98 ... Brazing material 99 ... joining members, 105,1 5,220A ... underlayer, 106,116,220B ... upper layer, 200 ... mobile phone as an electronic apparatus, 300 ... mobile computer as an electronic device, 500 ... transducer, 600 ... oscillator.

Claims (9)

The base,
A vibrating arm extending from one end of the base;
A drive electrode formed on the first surface of the vibrating arm,
The drive electrode includes a first electrode layer formed on the first surface, a first piezoelectric layer provided on the first electrode layer, and the first electrode layer sandwiching the first piezoelectric layer. A second electrode layer provided opposite to the first laminated body,
A second laminate including an electrically independent metal layer and a second piezoelectric layer provided on the metal layer is formed on a second surface that is in a front-back relationship with the first surface. A vibrating piece characterized by that. The resonator element according to claim 1,
The resonator element, wherein the first electrode layer and the metal layer have different metal compositions. In the resonator element according to claim 1 or 2,
A resonator element, wherein at least one of the first electrode layer and the metal layer has a laminated structure, and the layer configuration of the first electrode layer and the metal layer is different. In the resonator element according to any one of claims 1 to 3,
The vibrating piece, wherein the base and the vibrating arm are formed using a piezoelectric material. The resonator element according to claim 4,
A resonator element, wherein crystal is used as the piezoelectric material. The base,
A vibrating arm extending from one end of the base;
A drive electrode formed on the first surface of the vibrating arm,
The drive electrode includes a first electrode layer formed on the first surface, a first piezoelectric layer provided on the first electrode layer, and the first electrode layer sandwiching the first piezoelectric layer. A second electrode layer provided opposite to the first electrode layer,
A resonator element, wherein a second piezoelectric layer is formed on a second surface which is a back surface of the first surface.   A vibrator comprising: the resonator element according to claim 1; and a package that accommodates the resonator element.   A vibration piece according to any one of claims 1 to 6, a circuit element including an oscillation circuit that oscillates the vibration piece, and a package that accommodates the vibration piece and the circuit element. Transmitter.   An electronic device including the vibrator according to claim 7 or the oscillator according to claim 8.

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