JP2013042425A - Piezoelectric vibration piece and piezoelectric module - Google Patents

Abstract

The present invention provides a piezoelectric vibrating piece in which stress applied to a vibrating part during mounting is relaxed, and a piezoelectric module using the same.
A piezoelectric vibrating piece 10 in which a piezoelectric substrate is provided with a vibrating portion 22 that excites thickness shear vibration, and a peripheral edge portion 17 having a thickness smaller than the thickness of the vibrating portion 22 at a peripheral edge of the vibrating portion 22. The buffer portion 14 and the mount portion 12 are sequentially connected to the peripheral edge portion 17, and the buffer portion 14 includes a slit 16 between the mount portion 12 and the peripheral edge portion 14. The part 12 has notches 12 a at both ends in a direction orthogonal to the direction in which the mount part 12, the buffer part 14, and the peripheral part 17 are arranged.
[Selection] Figure 1

Description

  The present invention relates to a piezoelectric vibrating piece and a piezoelectric module using the same, and more particularly to a technique for mitigating the influence of stress on a vibrating portion at a mounting position generated after mounting.

  Conventionally, there is a form in which a piezoelectric vibrating piece is mounted and fixed to a package by applying a conductive adhesive. As described above, in the heat treatment step such as drying for curing the conductive adhesive, the distortion due to the difference in linear expansion coefficient among the piezoelectric vibrating piece, the package, and the conductive adhesive is reduced. There is a problem that the stress from the fixed part to the vibration part, that is, thermal strain, adversely affects the vibration.

  In addition, when attempting to reduce the size of the piezoelectric vibrating piece, the resonant stress of the piezoelectric vibrating piece may change over time due to residual stress generated by the curing of the adhesive applied to the support portion of the piezoelectric vibrating piece, or the excitation electrode The problem is that the area must be reduced, and the electrical characteristics of the piezoelectric vibrating piece deteriorate as a result. For example, the problem that impedance becomes large and good characteristics cannot be obtained appears remarkably.

  In view of such a problem, in Patent Document 1, regarding a thickness-slip piezoelectric vibrator such as an AT-cut quartz substrate having a rectangular flat shape, a notch or a slit is provided between the support portion and the vibration portion. Proposed structures are proposed.

  FIG. 21 shows a schematic diagram of a piezoelectric vibrator according to Patent Document 1. In FIG. 21A is a top view of the piezoelectric vibrating piece constituting the piezoelectric vibrator, FIG. 21B is a bottom view of the piezoelectric vibrating piece constituting the piezoelectric vibrator, and FIG. FIG. 21D is a cross-sectional view taken along the line AA ′ of FIG. 21C, and shows a plan view of the piezoelectric vibrator mounted inside.

  In FIG. 21, a rectangular piezoelectric vibrator 600 having a support part 602 and a vibration part 604 is shown. Excitation electrodes 606A and 606B formed on the upper and lower surfaces of the vibration part 604 of the piezoelectric vibrator 600, and an input / output terminal part 608A drawn from the excitation electrodes 606A and 606B to the edge of the support part 602 of the piezoelectric vibrator 600. , 608B, a slit 610 is disposed on the main surface of the piezoelectric vibrator 600. Thus, the excitation electrodes 606A and 606B and the input / output terminal portions 608A and 608B are physically separated from each other.

  In the above configuration, the adhesive 616 for fixing and electrically connecting the support portion 602 of the piezoelectric vibrator 600 and the connection electrode (not shown) of the bottom 614 in the container 612 that accommodates the piezoelectric vibrator 600 is cured. Then, the residual stress with respect to the piezoelectric vibrator 600 is generated over the direction and range indicated by the two-dot chain line in FIG. However, in such a structure, the residual stress is not propagated to the vibrating portion 604 by the slit 610, and the residual stress is propagated by setting the length in the longitudinal direction of the slit 610 to an optimum length. The direction can be limited to the outside of the region indicated by the two-dot chain line. As a result, it is said that a small piezoelectric vibrator 600 can be manufactured without impairing the electrical characteristics of the piezoelectric vibrator 600 and with little secular change in the resonance frequency of the piezoelectric vibrator. As a similar technique, a slit (see Patent Documents 2 to 6) or a notch (refer to Patent Documents 2, 3, 4, 5, 7, 8, and 9) between a portion where a conductive adhesive is applied and a vibration part ) Is disclosed. In addition, in order to ensure the strength and the like, a recess is formed in the central portion of the piezoelectric vibrating piece to form an inverted mesa type (see Patent Documents 10 to 12).

Japanese Patent Laid-Open No. 9-326667 JP 59-040715 A Japanese Utility Model Publication No. 61-187116 JP 2004-165798 A JP 2009-158999 A JP 2005-136705 A Japanese Patent No. 4087186 JP 2009-188483 A JP 2010-130123 A JP 2000-332571 A JP 2009-164824 A JP 2002-246869 A

  However, in the situation where the miniaturization and high performance of the device using such a piezoelectric vibrating piece have been accelerated in recent years, it is difficult to sufficiently remove the mount distortion in any of the above-described configurations. This has been found by the present inventors as shown below.

  FIG. 22 shows a stress distribution when a slit is formed between the mount portion and the vibration portion of the piezoelectric vibrating piece, and FIG. 22A shows a case where the width of the slit of the piezoelectric vibrating piece in the Z′-axis direction is 150 μm. FIG. 22B shows the stress distribution when the width of the slit of the piezoelectric vibrating piece in the Z′-axis direction is 250 μm. Further, in FIGS. 23 and 24, a notch is formed at a position between the mount portion and the vibration portion on both sides in the width direction of the piezoelectric vibrating piece, and the connection portion that connects the mount portion and the vibration portion. FIG. 23A shows the stress distribution when the width of the connecting portion in the X-axis direction is 400 μm, and FIG. 23B shows the width of the connecting portion in the X-axis direction of 300 μm. FIG. 24A shows the stress distribution when the width of the connecting portion in the X-axis direction is 200 μm, and FIG. 24B shows the stress when the width of the connecting portion in the X-axis direction is 100 μm. Show the distribution.

  22, 23, and 24 are compressed with respect to the piezoelectric vibrating piece 700 based on two points at the center of the circle on the surface on the Y′-axis side of the mount portion 702 to which the conductive adhesive in the drawing is applied. The simulation result of the stress distribution when stress or tensile stress is applied is shown. This compressive stress or tensile stress (residual stress) is generated by the stress applied to the piezoelectric vibrating piece due to the difference in thermal expansion coefficients of the piezoelectric vibrating piece, the conductive adhesive, and the substrate.

  22, 23, and 24, the X axis, the Y ′ axis, and the Z ′ axis are orthogonal to each other, and the piezoelectric vibrating piece 700 has a main surface whose normal is a direction parallel to the Y ′ axis. , And a plate-like outer shape each having an edge in a direction parallel to the Z ′ axis and a direction parallel to the X axis. A slit 704 is formed as a through-hole penetrating the main surface of the piezoelectric vibrating piece 700. Therefore, in the piezoelectric vibrating piece 700, the mount portion 702, the slit 704, and the vibrating portion 706 are arranged side by side. In FIG. 22, the piezoelectric vibrating piece 700 has an outer shape in which the length in the direction in which the mount portion 702, the slit 704, and the vibrating portion 706 are arranged (Z′-axis direction) is 1500 μm and the width in the X-axis direction is 1000 μm. The length of the slit 704 in the X-axis direction (long side) is 650 μm. The width in the Z′-axis direction from the long side of the slit 704 on the mount portion 702 side to the end of the mount portion 702 is 350 μm in FIG. 22A and 250 μm in FIG. The width of the slit 704 in the Z′-axis direction is 150 μm in FIG. 22A and 250 μm in FIG. That is, in FIG. 22A and FIG. 22B, the position and width of the slit 704 in the Z′-axis direction are changed.

  The plurality of patterns arranged in a vertical line on the left in FIGS. 22, 23, and 24 indicate the strength of stress received by the piezoelectric vibrating piece 700, and the stress increases as it goes to the upper pattern. And the lower the pattern, the lower the stress. And the distribution of the intensity of the stress which the piezoelectric vibrating piece 700 receives is represented using the above-mentioned pattern.

  As shown in FIG. 22, in such a small piezoelectric vibrating piece 700, even if the slit 704 is arranged and the position and width of the slit 704 are changed, the stress caused by the stress generated in the mount portion 702 It can be seen that strong stress reaches the vibrating portion 706 of the piezoelectric vibrating piece 700 without completely eliminating the above. Therefore, there is a problem that the electrical characteristics such as the stability of the resonance frequency of the piezoelectric vibrating piece 700 are adversely affected.

  The piezoelectric vibrating piece 700 shown in FIGS. 23 and 24 is provided with notches 708 at both ends in the width direction of the piezoelectric vibrating piece 700 between the mount portion 702 and the vibrating portion 706 according to the related art as in Patent Documents 6 and 7. A so-called notch structure is formed. In this structure, it is observed that the propagation of the stress generated in the mount portion 702 to the vibration portion 706 is reduced by reducing the width of the connecting portion 710 formed by the notch 708. However, the structure in which the vibrating portion 706 is supported only by the connecting portion 710 is disadvantageous in terms of strength such as a drop impact resistance and has a problem of poor practicality.

  Accordingly, the present invention focuses on the above-described problems, and an object thereof is to provide a piezoelectric vibrating piece and a piezoelectric module that can sufficiently reduce the propagation of stress from the mount portion to the vibration region.

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 application examples.
[Application Example 1] A piezoelectric vibrating piece in which a piezoelectric substrate is provided with a vibrating portion that excites thickness shear vibration, and a peripheral portion having a thickness smaller than the thickness of the vibrating portion at the periphery of the vibrating portion, A buffer portion and a mount portion are sequentially connected to the peripheral portion, the buffer portion has a slit between the mount portion and the peripheral portion, and the mount portion includes the mount portion and the buffer portion. A piezoelectric vibrating piece having notches at both ends in a direction orthogonal to a direction in which the peripheral edge is arranged.

  With the above configuration, it is possible to prevent the stress generated in the mount portion during mounting from being propagated linearly to the vibration portion by the slit. Therefore, the stress from the mount part propagates around the slit and the buffer part. Further, with the above configuration, the width of the mount portion becomes narrower than the width of the buffer portion due to the notch, so the path through which the stress propagates around the slit of the buffer portion becomes longer, and the peripheral portion and the vibration are increased by the length. The stress transmitted to the part can be relaxed. On the other hand, the piezoelectric vibrating piece of the present invention has a mesa structure in which the thickness of the vibrating portion is larger than the thickness of the peripheral portion. Therefore, the stress that circulates around the slit of the buffer portion can reach the vibration portion via the peripheral portion, but there is a step due to the mesa structure between the main surface of the peripheral portion and the main surface of the vibration portion. Therefore, the stress can be relaxed at this step position. Therefore, the stress is sufficiently relaxed before propagating to the vibrating part, and the influence of the stress on the vibrating part can be mitigated.

Application Example 2 The piezoelectric vibrating piece according to Application Example 1, wherein the connecting portion between the buffer portion and the peripheral portion has a notch.
With the above configuration, it is possible to block the propagation of the stress that has propagated to the positions at the peripheral edges of the longitudinal direction of the slit of the buffer portion by the notch, so that the stress to the vibration portion can be blocked. The impact can be mitigated.

[Application Example 3] Application Example 1 in which the width of the peripheral portion is narrower than the width of the buffer portion with respect to the direction orthogonal to the direction in which the mount portion, the buffer portion, and the peripheral portion are arranged. 2. The piezoelectric vibrating piece according to 2.
With the above configuration, it is possible to reduce the weight of the free end side of the piezoelectric vibrating piece and improve the mounting stability.

Application Example 4 The X-axis of an orthogonal coordinate system in which the piezoelectric substrate is an X-axis as an electric axis, a Y-axis as a mechanical axis, and a Z-axis as an optical axis, which are crystal axes of quartz. , The Z axis is tilted in the −Y direction of the Y axis as the Z ′ axis, the Y axis is tilted in the + Z direction of the Z axis as the Y ′ axis, and the X axis and the 4. The piezoelectric vibrating piece according to any one of application examples 1 to 3, wherein the piezoelectric vibrating piece is a quartz crystal substrate having a plane parallel to the Z ′ axis and having a thickness in a direction parallel to the Y ′ axis.
With the above configuration, a piezoelectric vibrating piece capable of efficiently oscillating thickness shear vibration is obtained.

Application Example 5 The peripheral portion includes a first peripheral portion connected to the buffer portion and a second peripheral portion disposed on the peripheral portion of the vibrating portion and connected to the first peripheral portion. The piezoelectric vibrating piece according to any one of Application Examples 1 to 4, wherein the thickness of the second peripheral edge is thicker than the thickness of the first peripheral edge.
With the above configuration, a two-stage mesa structure centered on the vibration part is obtained, so that the thickness shear vibration can be effectively confined in the vibration part, and the excitation efficiency can be increased.

Application Example 6 Excitation electrodes are arranged on both the main surfaces of the front and back sides of the vibration part, and a pair of extraction electrodes electrically connected to the excitation electrodes are arranged on the mounting surface of the mount part. The piezoelectric vibrating piece according to Application Example 5, wherein the piezoelectric vibrating piece is applied.
With the above configuration, by connecting the extraction electrode and the connection electrode arranged on the mounting substrate on which the piezoelectric vibrating piece is mounted with a conductive adhesive, mechanically and electrically connecting the extraction electrode and the connection electrode, A so-called face-down bonding type mounting form can be adopted. Therefore, it is possible to reduce the height of the module structure including the piezoelectric vibrating piece and the mounting substrate.

[Application Example 7] The piezoelectric vibrating reed is mounted by adhering the mounting portion of the piezoelectric vibrating piece according to any one of Application Examples 1 to 6 to a connection electrode disposed on the mounting substrate with a conductive adhesive. In the piezoelectric module, a lid that covers the piezoelectric vibrating piece is disposed on the mounting substrate, a recess is disposed on a surface of the mounting substrate that faces the piezoelectric vibrating substrate, and the recess includes the A piezoelectric module comprising a mounting substrate and a temperature sensitive element capable of measuring a temperature of an internal space closed by the lid.
With the above configuration, since the temperature around the piezoelectric vibrating piece can be measured, the piezoelectric module can perform temperature compensation of the oscillation signal oscillated from the piezoelectric vibrating piece with high accuracy.

Application Example 8 The piezoelectric vibrating reed is obtained by bonding the mounting portion of the piezoelectric vibrating piece according to any one of Application Examples 1 to 6 and the connection electrode disposed on the mounting substrate with a conductive adhesive. A lid that covers the piezoelectric vibrating piece is disposed on the mounting substrate, and a concave portion is disposed on a surface opposite to the surface of the mounting substrate that faces the piezoelectric vibrating substrate. A piezoelectric module, wherein a temperature sensitive element capable of measuring the temperature of the mounting substrate is disposed in the recess.
With the above configuration, after mounting the piezoelectric vibrating piece on the mounting board and before mounting the temperature sensitive element, the operation of the piezoelectric vibrating piece is inspected, and after confirming the normal operation of the piezoelectric vibrating piece, the temperature sensitive element is mounted. Therefore, the temperature sensing element is not wasted and the cost can be suppressed.

FIG. 1A is a schematic view of a piezoelectric vibrating piece according to a first embodiment, FIG. 1A is a plan view, FIG. 1B is a bottom view, and FIG. 1C is a diagram illustrating a cut angle of a quartz substrate. 2A and 2B are schematic views of the piezoelectric vibrating piece according to the first embodiment, in which FIG. 2A is a front view, FIG. 2B is a back view, and FIG. 2C is a cross-sectional view taken along line AA in FIG. FIG. It is a schematic diagram which shows the manufacturing process (vibration part formation process) of a piezoelectric vibrating piece. It is a schematic diagram of the manufacturing process (outer shape forming process) of a piezoelectric vibrating piece. It is a schematic diagram of the manufacturing process (electrode formation process) of a piezoelectric vibrating piece. FIG. 6A is a schematic view of a piezoelectric vibrating piece according to a second embodiment, FIG. 6A is a plan view, FIG. 6B is a bottom view, and FIG. 6C is a cross-sectional view taken along line AA in FIG. FIG. 6 and FIG. 6D are cross-sectional views taken along the line BB in FIG. FIG. 7A is a modification of the piezoelectric vibrating piece according to the first embodiment, FIG. 7A is a plan view, FIG. 7B is a bottom view, and FIG. 7C is a side view. FIG. 8A is a plan view, FIG. 8B is a bottom view, and FIG. 8C is a side view, illustrating a first modification of the piezoelectric vibrating piece according to the second embodiment. FIGS. 9A and 9B are schematic views of a second modification of the piezoelectric vibrating piece according to the second embodiment, in which FIG. 9A is a plan view, FIG. 9B is a bottom view, and FIG. 9C is FIG. FIG. 9D is a sectional view taken along line AA, and FIG. 9D is a sectional view taken along line BB in FIG. FIG. 10A is a schematic diagram of a piezoelectric vibrating piece according to a third embodiment, FIG. 10A is a plan view, FIG. 10B is a bottom view, and FIG. 10C is a cross-sectional view taken along line AA in FIG. FIG. 10D is a cross-sectional view taken along line BB in FIG. It is a side view of the piezoelectric vibrating piece according to the third embodiment. FIG. 12A is a schematic view of a piezoelectric vibrating piece according to a fourth embodiment, FIG. 12A is a plan view, FIG. 12B is a bottom view, and FIG. 12C is a cross-sectional view taken along line AA in FIG. Fig. 12 (d) is a cross-sectional view taken along line BB of Fig. 12 (a). It is a side view of the piezoelectric vibrating piece according to the fourth embodiment. It is a figure which shows strength distribution of the stress at the time of applying a stress to the mount part of the piezoelectric vibrating piece of this embodiment. FIG. 15A is a plan view of the piezoelectric vibrator 100 when the piezoelectric vibrating piece 60 shown in FIG. 6 is mounted, and FIG. 15B is a diagram. It is AA sectional view taken on the line of 15 (a). FIG. 7 is an exploded perspective view of a piezoelectric module when the piezoelectric vibrating piece 60 shown in FIG. 6 is mounted. FIG. 17A is a sectional view taken along line AA of FIG. 16 and FIG. 17B is a piezoelectric vibrating piece 61 shown in FIG. It is an AA line sectional view at the time of carrying. It is a figure which shows the 1st modification of the piezoelectric module of this embodiment. The 2nd modification of the piezoelectric module of this embodiment is shown, Fig.19 (a) is a side view, FIG.19 (b) is a top view of the board | substrate which comprises a piezoelectric module. FIG. 20A shows a third modification of the piezoelectric module of the present embodiment, FIG. 20A is a schematic view of a piezoelectric module having a so-called H-shaped structure, and FIG. 20B is a diagram of a single seal type piezoelectric module. It is a schematic diagram. FIG. 21A is a schematic diagram of a piezoelectric vibrator according to Patent Document 1. FIG. 21A is a top view of a piezoelectric vibrating piece constituting the piezoelectric vibrator, and FIG. 21B is a bottom face of the piezoelectric vibrating piece constituting the piezoelectric vibrator. Fig. 21 (c) is a plan view of a piezoelectric vibrator having a piezoelectric vibrating piece mounted inside the container, and Fig. 21 (d) is a cross-sectional view taken along line AA 'of Fig. 21 (c). FIG. 22A shows the stress distribution when a slit is formed between the mount portion and the vibrating portion of the piezoelectric vibrating piece. FIG. 22A shows the stress distribution when the slit width of the piezoelectric vibrating piece is 150 μm. ) Is a stress distribution when the width of the slit of the piezoelectric vibrating piece is 250 μm. The stress distribution when a notch is formed at a position between the mount part and the vibration part on both sides in the width direction of the piezoelectric vibrating piece to form a connection part that connects the mount part and the vibration part is shown. FIG. 23A shows the stress distribution when the width of the connecting portion is 400 μm, and FIG. 23B shows the stress distribution when the width of the connecting portion is 300 μm. The stress distribution when a notch is formed at a position between the mount part and the vibration part on both sides in the width direction of the piezoelectric vibrating piece to form a connection part that connects the mount part and the vibration part is shown. FIG. 24A shows the stress distribution when the width of the connecting portion is 200 μm, and FIG. 24B shows the stress distribution when the width of the connecting portion is 100 μm.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. . In the drawings used in the following description, the X axis, the Y ′ axis, and the Z ′ axis are assumed to be orthogonal to each other.

  The piezoelectric vibrating piece according to the first embodiment is shown in FIGS. 1 (a) is a plan view, FIG. 1 (b) is a bottom view, FIG. 1 (c) is a diagram showing a cut angle of a quartz substrate, FIG. 2 (a) is a front view, and FIG. 2 (b) is a back view. FIG. 2C is a cross-sectional view taken along line AA in FIG. The piezoelectric vibrating piece 10 according to the present embodiment includes, as a piezoelectric substrate (piezoelectric element plate), an X axis as an electric axis, a Y axis as a mechanical axis, and a Z axis as an optical axis, which are crystal axes of quartz. An axis obtained by tilting the Z axis in the −Y direction of the Y axis with respect to the X axis of the Cartesian coordinate system comprising the Z ′ axis and an axis inclining the Y axis in the + Z direction of the Z axis. An AT-cut quartz substrate is adopted that has a Y'-axis, a plane that is parallel to the X-axis and the Z'-axis, and has a thickness parallel to the Y'-axis. Then, by using a rectangular AT-cut quartz substrate and leaving the peripheral edge portion 17 (reinforcement portion) at the peripheral edge, the short side direction becomes the X-axis direction and the long side direction becomes the Z′-axis direction. This is an inverted mesa type piezoelectric vibrating piece 10 having an outer shape and a thin vibrating portion 22 having a thickness smaller than that of the peripheral edge portion 17 (first peripheral edge portion 17a).

  The piezoelectric vibrating piece 10 has a mount 12, a buffer 14 having a slit 16, and a peripheral part 17 having a vibration part 22 at the center to form an overall outer shape. The mount 12 and the peripheral part 17 are respectively The piezoelectric vibrating piece 10 is disposed at an end portion in the long side direction (Z′-axis direction), and the buffer portion 14 is disposed between the mount portion 12 and the peripheral portion 17. The piezoelectric vibrating piece 10 has a line-symmetric shape with the AA line in FIG. The piezoelectric vibrating reed 10 is fixed to the mounting substrate 34 (FIG. 2) by the conductive adhesive 32 in a cantilevered state with the mounting portion 12 side as a fixed end and the vibrating portion 22 side as a free end.

  The mount portion 12 is disposed at one end portion of the Z ′ axis of the piezoelectric vibrating piece 10, and notches 12 a are formed at both ends in the X axis direction. The notch 12a is disposed so that both ends of the mount portion 12 in the X-axis direction are notched into a rectangle. By this notch 12a, the interval between the application positions of the conductive adhesive 32 can be narrowed, and the generation area of the stress generated in the mount portion 12 during mounting can be reduced. Pad electrodes 28A and 28B that are electrically connected to excitation electrodes 24A and 24B, which will be described later, are arranged on one main surface (the surface on the −Y′-axis side) of the mount portion serving as a mounting surface. A conductive adhesive 32 is applied to the pad electrodes 28A and 28B to adhere to the mounting substrate 34 on the mounting side. Accordingly, the piezoelectric vibrator is formed by bonding to the mounting substrate 34 using the conductive adhesive 32.

  The buffer portion 14 is formed between the mount portion 12 and the peripheral portion 17 and has a function of relaxing stress (thermal strain) generated in the mount portion 12 and propagating to the vibrating portion 22 side. In order to realize this, the buffer portion 14 is provided with a slit 16, and a notch 18 is formed between the buffer portion 14 and the peripheral edge portion 17. The buffer portion 14 is formed with extraction electrodes 26A and 26B described later.

  The slit 16 has a long side along the short side direction (X-axis direction) of the piezoelectric vibrating piece 10 and a short side along the long side direction (Z′-axis direction) of the piezoelectric vibrating piece 10. It is a through-hole penetrating in a rectangular shape in the thickness direction. As will be described later, the slit 16 blocks the linear propagation of the stress generated in the mount 12 when the piezoelectric vibrating piece 10 is mounted on the mounting substrate 34 in the Z-axis direction (long side direction of the piezoelectric vibrating piece 10). Thus, the stress applied to the vibration part 22 is reduced. On the other hand, the stress (thermal strain) during mounting of the piezoelectric vibrating piece 10 is generated on the line connecting the application positions of the conductive adhesive 32 of the mount portion 12. Therefore, the width in the long side direction of the slit 16 is longer than the interval between the application positions of the conductive adhesive 32 and is arranged so as to intersect with the straight line connecting the generation region and the vibration part 22. The linear propagation path to the vibration part 22 side of the stress generated in the generation region can be blocked. In particular, as shown in FIG. 1, the width in the long side direction of the slit 16 is made wider than the width in the X axis direction of the mount portion 12, and both end portions of the long side of the slit 16 as viewed from the Z ′ axis direction are By arranging so as to protrude from both end portions in the X-axis direction, the propagation path of the stress generated in the mount portion 12 to the vibration portion 22 side can be reliably blocked. With the above configuration, the path where the stress generated in the above-described generation region (mount portion 12) is linearly propagated to the vibrating portion 22 by the slit 16 is blocked, and the stress is circulated around the slit 16 of the buffer portion 14. become.

  The notch 18 is disposed at a position that becomes a boundary (connecting portion) between the buffer portion 14 and the peripheral portion 17, and the buffer portion 14 and the peripheral portion 17 (from the both sides in the short side direction (X-axis direction) of the piezoelectric vibrating piece 10. The first peripheral portion 17a) is arranged so as to be cut out. Therefore, a region sandwiched between the notches 18 of the buffer portion 14 and the peripheral edge portion 17 (first peripheral edge portion 17a) becomes a constricted portion 20. The notch 18 is arranged to block a linear propagation path to the vibration part 22 of the stress propagated to the positions at the peripheral edges of both ends in the long side direction of the slit 16 of the buffer part 14. Therefore, it is desirable that the width in the X-axis direction of the constricted portion 20 formed by the notch 18 is approximately equal to or less than the width of the slit 16 in the long side direction (X-axis direction). Accordingly, the stress propagated to the above-described position is blocked from linear propagation to the vibration part 22 by the notch 18 and propagates to the vibration part 22 side via the constricted part 20.

  The peripheral portion 17 is a member that constitutes the + Z axis side of the piezoelectric vibrating piece 10 and supports the vibrating portion 22. The peripheral portion 17 includes a first peripheral portion 17a connected to the buffer portion 14 and a second peripheral portion 17b disposed so as to surround the periphery of the vibration portion 22 and connected to the first peripheral portion 17a. . Here, the first peripheral portion 17 a has the same thickness as the buffer portion 14, and the second peripheral portion 17 b has the same thickness as the vibrating portion 22. In FIG. 1, the + Z′-axis side of the first peripheral portion 17a is cut away, and the end surface on the + Z′-axis side of the second peripheral portion 17b is exposed. This portion also includes the first peripheral portion. 17a may be arranged so that the second peripheral edge portion 17b is completely surrounded by the first peripheral edge portion 17a. In the present embodiment, the first peripheral portion 17a has the same thickness as the buffer portion 14 and does not have a step, and the second peripheral portion 17 has the same thickness as the vibrating portion 22 and has no step. Shall. In addition, the second peripheral edge portion 17b and the vibrating portion 22 are thinner than the first peripheral edge portion 17a, and are connected to the first peripheral edge portion 17a in a state of being dug from the −Y′-axis direction of the piezoelectric vibrating piece 10. doing.

  The vibrating part 22 is a part that is disposed so as to be surrounded by the second peripheral edge part 17 b and generates a thickness shear vibration in the piezoelectric vibrating piece 10. Excitation electrodes 24 </ b> A and 24 </ b> B are formed on both main surfaces (front and back surfaces) of the vibration unit 22 so as to face each other. An extraction electrode 26A is extracted from the excitation electrode 24A formed on the surface on the + Y′-axis side. The extraction electrode 26 </ b> A is disposed across the vibrating portion 22, the second peripheral portion 17 b, the first peripheral portion 17 a, and the buffer portion 14, and is extracted to the surface on the −Y′-axis side of the piezoelectric vibrating piece 10 at the notch 18. In addition, it is connected to the pad electrode 28 </ b> A via the buffer portion 14 and the mount portion 12. Further, an extraction electrode 26B is extracted from the excitation electrode 24B formed on the surface at the −Y′-axis side. The extraction electrode 26B is disposed across the vibration part 22, the second peripheral part 17b, the first peripheral part 17a, the buffer part 14, and the mount part 12, and is connected to the pad electrode 28B. Therefore, by applying an AC voltage to the pad electrodes 28A and 28B, the vibrating portion 22 can perform thickness shear vibration at a predetermined frequency.

  By the way, in the bonding process of the piezoelectric vibrating piece 10 using the conductive adhesive 32, it is necessary to expose the piezoelectric vibrating piece 10 to a high temperature in order to cure the conductive adhesive 32. Therefore, when the temperature after bonding decreases, the difference in thermal expansion coefficient between the piezoelectric vibrating piece 10, the mounting substrate 34, and the conductive adhesive 32 is a region connecting the two points where the conductive adhesive 32 of the mount portion 12 is applied. As a result, the above-described stress (thermal strain) is generated and propagates to the entire piezoelectric vibrating piece 10.

  On the other hand, when a stress is applied to the vibration part 22, the apparent rigidity of the vibration part 22 changes, so that the resonance frequency varies. Since the mount state of the mount portion 12 differs depending on the mounting state, the stress propagating to the vibration portion 22 also varies, and the resonance frequency varies.

  However, in the mount part 12, the bonding position of the conductive adhesive 32 is close by the notch 12a. Therefore, the stress generation range can be concentrated on the region where the conductive adhesive 32 is applied, the stress generation region can be reduced, and the stress component propagating to other regions can be suppressed. The stress generated at the bonding position of the conductive adhesive 32 propagates linearly toward the buffer portion 14 (Z′-axis direction), but the linear propagation path is blocked by the slit 16, and the stress is applied to the slit 16. It will propagate along the periphery. Therefore, since the stress propagates around the slit 16, the path becomes long. Further, since the bonding position of the conductive adhesive 32 in the mount portion 12 is close to the center side of the long side of the slit 16 due to the notch 12a, the path around the stress slit 16 becomes further longer. Therefore, the stress is sufficiently relaxed before propagating to the vibration part 22, and the influence of the stress on the vibration part 22 can be relaxed. Furthermore, the slit 16 can not only lengthen the propagation path of the stress but also bend the propagation path, so that the relaxation of the stress can be promoted accordingly.

  Further, the propagation path is linearly blocked by the notch 18 to the vibration portion 22 of the stress propagated to both ends in the X-axis direction of the buffer portion 14, and the first peripheral portion 17 a side around the slit 16 of the buffer portion 14. Propagated to the position and the constricted part 20. Accordingly, the stress propagation path is extended and bent in the same manner as described above, so that the stress propagating to the vibrating portion 22 can be relaxed.

  Moreover, the 2nd peripheral part 17b and the vibration part 22 are formed more thinly than the 1st peripheral part 17a. Thereby, since the vibration part 22 receives only a part of the stress that has propagated to the first peripheral edge part 17a, the stress that propagates to the vibration part 22 can be reduced. In addition, the piezoelectric vibrating piece 10 of the present embodiment has a so-called reverse mesa structure in which the vibrating portion 22 (second peripheral portion 17b) is thinner than the thickness of the first peripheral portion 17a. Therefore, the stress transmitted to the buffer part 14 (the constricted part 20) can reach the vibration part 22 via the first peripheral part 17a and the second peripheral part 17b, but the main surface of the first peripheral part 17a. There is a step due to an inverted mesa structure between the main surface of the second peripheral portion 17b (the main surface of the vibrating portion 22), and stress will be relieved at this step position as will be described later (see FIG. 14). Can do. Further, as shown in FIG. 1, the second peripheral edge portion 17b and the vibration portion 22 are half-etched from the surface side (the surface side on the −Y ′ axis side) to which the conductive adhesive 32 of the peripheral edge portion 17 is applied. It is arranged in a dug out manner. As a result, the connection position between the first peripheral edge portion 17a and the second peripheral edge portion 17b (vibrating portion 22) is set to the surface (the surface on the −Y′-axis side) on which the pad electrodes 28A and 28B of the piezoelectric vibrating piece 10 are disposed. A step is formed between the main surface of the vibrating portion 22 and the main surface of the first peripheral edge portion 17a in a state of being unevenly distributed on the opposite surface (+ Y′-axis side surface). As a result, the distance between the conductive adhesive 32 applied to the pad electrodes 28A and 28B and the vibration part 22 is increased by the aforementioned step, so that the stress propagating to the vibration part 22 can be more relaxed.

  As described above, in the piezoelectric vibrating piece 10, the width of the mount portion 12 is narrowed by the notch 12a, thereby reducing the stress generation region in the mount portion 12 and reducing the generated stress itself. Further, the linear propagation path of the stress generated in the mount portion 12 to the vibration portion 22 by the slit 16 is cut off and circulated around the slit of the buffer portion 14 to lengthen the stress propagation path. Stress relaxation is promoted by bending the stress path. Further, the notch 18 blocks a linear propagation path to the vibrating portion 22 of the stress that has reached the periphery of both ends of the slit 16 of the buffer portion 14 in the long side direction, The relaxation of the stress is promoted by making it circulate around the vibration portion 22 side and the constricted portion 20, lengthening the propagation path of the stress, and bending the stress path. Finally, the stress that reaches the constricted portion 20 (the first peripheral portion 17a) is between the main surface of the first peripheral portion 17a and the main surface of the second peripheral portion 17b (the main surface of the vibrating portion 22). It is alleviated by the level difference. Therefore, the stress that can be generated in the mounting portion 12 when the piezoelectric vibrating piece 10 is mounted is reduced by the notch 12a, and the stress is reduced while bypassing the periphery of the slit 16 and the constricted portion 20, and the first peripheral portion. It is relaxed at the boundary between 17a and the second peripheral edge 17b. As a result, the stress propagating to the vibrating portion 22 can be relaxed to suppress frequency fluctuations, and variations in characteristics such as the resonance frequency and the Q value of the piezoelectric vibrator using this can be suppressed to increase the yield.

Next, the manufacturing process of the piezoelectric vibrating piece according to the first embodiment will be described.
3 shows a manufacturing process (vibration portion forming process) of the piezoelectric vibrating piece, FIG. 4 shows a manufacturing process (outer shape forming process) of the piezoelectric vibrating piece, and FIG. 5 shows a manufacturing process (electrode forming process) of the piezoelectric vibrating piece. Indicates. As a rough procedure, in the quartz substrate 36 which is the material of the piezoelectric vibrating piece 10, the position corresponding to the vibrating portion 22 (second peripheral portion 17 b) is half-etched and etched following the outer shape of the piezoelectric vibrating piece 10. The excitation electrodes 24A and 24B, the extraction electrodes 26A and 26B, and the pad electrodes 28A and 28B are formed.

  As shown in FIG. 3, first, the outer shape of the vibrating portion 22 (second peripheral portion 17 b) constituting the piezoelectric vibrating piece 10 is formed. First, as shown in FIG. 3A, an AT-cut quartz substrate 36 is prepared as a piezoelectric substrate, and a resist film 38 is applied on the quartz substrate 36. Then, as shown in FIG. 3B, the resist film 38 is exposed using a photomask 40 corresponding to the shape of the vibrating portion 22 (second peripheral edge portion 17b), and as shown in FIG. The resist film 38a thus removed is removed. Then, as shown in FIG. 3D, half etching is performed until the portion where the quartz substrate 36 is exposed reaches the thickness of the vibrating portion 22 (second peripheral edge portion 17b), and as shown in FIG. 38 is removed. At this time, a concave portion 22a corresponding to the vibrating portion 22 and the second peripheral edge portion 17b is formed in the quartz substrate.

  Next, the outer shape of the piezoelectric vibrating piece 10 is formed. As shown in FIG. 4A, a resist film 42 is applied to the quartz substrate 36 on which the recesses 22a are formed. Then, as shown in FIG. 4B, the resist film 42 is exposed using a photomask 44 corresponding to the shape of the piezoelectric vibrating piece 10, the slit 16, and the notch 18, and exposed as shown in FIG. 4C. The resist film 42a is removed. Then, as shown in FIG. 4D, etching is performed until the exposed portion of the quartz substrate 36 penetrates, and the resist film 42 is removed as shown in FIG. Thereby, the piezoelectric element plate 10a having the outer shape of the piezoelectric vibrating piece 10 is formed.

  Then, electrodes are formed on the piezoelectric element plate 10a. First, as shown in FIG. 5A, a metal film 46 of Cr, Au or the like is deposited on the entire surface of the piezoelectric element plate 10a by sputtering or the like. At this time, the metal film 46 is also deposited on the end face of the piezoelectric element plate 10a. Then, as shown in FIG. 5B, a resist film 48 is applied to the entire surface of the piezoelectric base plate 10a on which the metal film 46 is deposited. At this time, the resist film 48 is also applied to the end face of the piezoelectric element plate 10a. Next, as shown in FIG. 5C, the excitation electrodes 24A and 24B, the extraction electrodes 26A and 26B (not shown in FIG. 5) and the pad electrodes 28A and 28B (not shown in FIG. 5) on both surfaces of the piezoelectric vibrating piece 10 are formed. The resist film is exposed using a photomask 50 corresponding to the shape. At this time, the resist film 48 covering the portion of the extraction electrode 26A passing through the end face of the piezoelectric vibrating piece 10 is not exposed. Next, the exposed resist film 48a is removed as shown in FIG. 5D, and the portions corresponding to the excitation electrodes 24A and 24B, the extraction electrodes 26A and 26B, and the pad electrodes 28A and 28B as shown in FIG. 5E. Etching is performed with the other metal film 46 exposed. At this time, the metal film 46 deposited on the end face is protected by the remaining resist film 42 without being exposed to light. Therefore, a portion of the metal film 46 that passes through the end face of the extraction electrode 26A remains, and the pad electrode 28A is maintained in electrical connection with the excitation electrode 24A on the opposite surface via the extraction electrode 26A. Then, as shown in FIG. 5 (f), the piezoelectric vibrating piece 10 is formed by removing the resist film 48.

  FIG. 6 shows a piezoelectric vibrating piece according to the second embodiment, FIG. 6 (a) is a plan view, FIG. 6 (b) is a bottom view, and FIG. 6 (c) is a cross-sectional view taken along line AA in FIG. FIG. 6D is a cross-sectional view taken along line BB in FIG. In the following embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted unless necessary. The piezoelectric vibrating piece 60 of the second embodiment is basically similar to the first embodiment, but is orthogonal to the direction in which the mount portion 12, the buffer portion 14, and the peripheral portion 62 are arranged (Z′-axis direction). Regarding the direction (X-axis direction), the width of the peripheral edge portion 62 is different in that it is formed narrower than the width of the buffer portion 14 (feature 1). In addition, the peripheral edge 62 includes a first peripheral edge 62a connected to the shock absorber 14 and a second peripheral edge 62b disposed around the vibration part 22 and connected to the first peripheral edge 62a. Have. However, the thickness of the second peripheral edge 62b is different in that it is thinner than the thickness of the vibration part 22 (feature 2). In the second embodiment, the excitation electrodes 24 </ b> A and 24 </ b> B are disposed on the entire surface of the vibration unit 22. The vibrating portion 22 has a form in which the surface on the + Y′-axis side is flush with the second peripheral edge portion 62b and protrudes from the second peripheral edge portion 62b on the −Y′-axis side surface.

  The manufacturing process of the piezoelectric vibrating piece 60 according to the second embodiment includes a process of forming the second peripheral edge 62b that is thinner than the vibrating part 22 in addition to the process of forming the vibrating part 22 in the half etching process. Otherwise, it is common to the first embodiment.

  The width of the peripheral portion 62 in the X-axis direction may be the same as the width of the mount portion 12 in the X-axis direction, or may be shorter / longer, but the piezoelectric vibrating piece 60 is shown in FIG. It preferably has a line-symmetric shape with the A-A line as the center line. Further, the width in the X-axis direction of the constricted portion 20 formed by the notch 18 matches the width in the X-axis direction of the first peripheral edge portion 62a.

  By having the feature 1 described above, the free end side of the piezoelectric vibrating piece 60 can be reduced in weight and the mounting stability can be improved. Furthermore, by having the feature 2, it is possible to confine the energy of the main vibration, which is the thickness shear vibration, in the vibration portion 22 and increase the excitation efficiency of the thickness shear vibration.

  FIG. 7 shows a modification of the first embodiment, and FIG. 8 shows a first modification of the second embodiment. 7A is a plan view, FIG. 7B is a bottom view, and FIG. 7C is a side view. 8A is a plan view, FIG. 8B is a bottom view, and FIG. 8C is a side view. As shown in FIG. 7, in the modified example of the first embodiment, a portion (first peripheral portion 17 a ′) of the first peripheral portion 17 a that is connected to the ± X axis side of the vibrating portion 22 is the first peripheral portion. It is disposed so as to have a main surface that is thinner than the peripheral edge portion 17a and is flush with the main surface of the second vibration portion 17b (vibration portion 22). As shown in FIG. 8, in the first modification of the second embodiment, a portion of the first peripheral portion 62 a that is connected to the ± X axis side of the vibrating portion 22 (first peripheral portion 62 a ′). Are arranged so as to have a main surface that is thinner than the first peripheral portion 62a and is flush with the main surface of the second peripheral portion 62b.

  With the above configuration, the free end side of the piezoelectric vibrating piece can be reduced in weight to improve mounting stability, and the second peripheral edge portions 17b and 62b and the first peripheral edge portions 17a ′ and 62a ′ are flush with each other. Is forming. Therefore, in the modification of the first embodiment, the vibrating portion 22, the second peripheral edge portion 17b, and the first peripheral edge portion 17a ′ can be easily formed in the same process, and the first modification of the second embodiment. In the example, the second peripheral edge 62b and the first peripheral edge 62a 'can be easily formed in the same process.

  FIG. 9 shows a second modification of the piezoelectric vibrating piece according to the second embodiment. FIG. 9 (a) is a plan view, FIG. 9 (b) is a bottom view, and FIG. 9 (c) is FIG. FIG. 7D is a cross-sectional view taken along the line A-A in FIG. 9A. As shown in FIG. 9, in the second modification of the second embodiment, the vibrating portion 22 is disposed so as to protrude from both main surfaces of the second peripheral edge portion 62b. At this time, the vibrating portion 22 is formed by half-etching the shape of the vibrating portion 22 from both main surfaces of the quartz substrate. In this way, by arranging the vibrating portion 22 so as to protrude from both main surfaces of the second peripheral edge portion 62b, the piezoelectric vibrating piece 61 can be obtained in which the effect of confining the thickness shear vibration is enhanced as compared with the second embodiment. it can. In the second embodiment, the excitation electrodes 24A and 24B are formed in a rectangular shape on the entire surface of the vibration part 22. However, the excitation electrodes 24A and 24B do not have to be disposed so as to cover the entire surface of the vibration part 22, and the thickness slip in the vibration part 22 is further avoided. For example, a circular shape or an elliptical shape may be used corresponding to the actual vibration region of the vibration. By doing so, the energy of the main vibration which is the thickness shear vibration can be confined in the vibration part 22.

  10A and 10B are schematic views of the piezoelectric vibrating piece according to the third embodiment. FIG. 10A is a plan view, FIG. 10B is a bottom view, and FIG. 10C is A in FIG. -A sectional view, FIG.10 (d) shows the BB sectional drawing of Fig.10 (a). FIG. 11 shows a side view of the piezoelectric vibrating piece according to the third embodiment. The piezoelectric vibrating piece 70 of the third embodiment is basically similar to the first and second embodiments, but is arranged so that the short side direction is the Z′-axis direction and the long side direction is the X-axis direction. ing. The difference is that the vibrating portion 22 is disposed so as to be thicker than the first peripheral portion 72. Further, the vibrating portion 22 is disposed such that both main surfaces thereof protrude from both main surfaces of the first peripheral edge portion 62. With the above configuration, the vibration region of the thickness shear vibration can be confined in the vibration portion 22 to enhance the excitation efficiency, and stress propagating from the mount portion 12 to the vibration portion 22 can be reduced as will be described later. In the present embodiment, the propagation process of stress generated in the mount portion 12 and the relaxation process of the stress are the same as those in the first embodiment from the mount portion 12 to the constricted portion 20. In the present embodiment, the vibrating portion 22 has a mesa structure that is thicker than the first peripheral portion 72. Therefore, a step is formed at the boundary between the vibrating portion 22 and the first peripheral portion 72, and the stress generated at the mount portion 12 and reaching the boundary between the first peripheral portion 72 and the vibrating portion 22 is relaxed by this step. The stress propagating to the vibration part 22 can be relaxed.

  In addition, in the manufacturing process of the piezoelectric vibrating piece according to the third embodiment, a quartz substrate having the same thickness as that of the vibrating unit 22 is prepared, and the mounting unit 12 and the buffer unit are provided on both sides of the quartz substrate, leaving portions to be the vibrating unit 22. 14, half-etching is performed until the thickness of the peripheral portion 62 is reached, and etching is performed to penetrate the outer shape of the piezoelectric vibrating piece 70 except for the mount portion 12, the buffer portion 14 (slit 16), and the first peripheral portion 72. Just do it. The subsequent electrode formation process is the same as that of the first embodiment.

  12A and 12B are schematic views of the piezoelectric vibrating piece according to the fourth embodiment. FIG. 12A is a plan view, FIG. 12B is a bottom view, and FIG. 12C is A in FIG. -A sectional view, FIG.12 (d) shows the BB sectional drawing of Fig.12 (a). FIG. 13 shows a side view of the piezoelectric vibrating piece according to the fourth embodiment. The piezoelectric vibrating piece 71 of the fourth embodiment is similar to the third embodiment, but differs in that it has a second peripheral portion 74 that is disposed around the vibrating portion 22 and connected to the first peripheral portion 72. The thickness is different in that it is thicker than the thickness of the first peripheral edge 72. Here, the second peripheral edge portion 74 is arranged such that both main surfaces protrude from both main surfaces of the first peripheral edge portion 72, and the vibration portion 22 has both main surfaces extending to the second peripheral edge portion 74. It arrange | positions so that it may protrude from both main surfaces. The excitation electrodes 24 </ b> A and 24 </ b> B are arranged so as to cover not only the main surface of the vibration part 22 but also the main surface of the second peripheral edge 74. With the above configuration, the piezoelectric vibrating piece 71 has a two-stage mesa structure with the vibrating portion 22 as the center, so that the thickness shear vibration can be effectively confined in the vibrating portion 22 and the excitation efficiency can be increased. In particular, in the present embodiment, the excitation electrodes 24A and 24B are arranged so as to cover not only the vibration part 22 but also the second peripheral edge part 74, so that the excitation efficiency in the vibration part 22 is increased and the CI value is improved. be able to. In addition, since the present embodiment has a so-called two-stage mesa structure, the number of steps in the thickness direction of the piezoelectric vibrating piece 71 is larger than that in the third embodiment, so that the stress propagating from the mount portion 12 to the vibrating portion 22 is increased. This can be further relaxed than in the third embodiment.

  In the manufacturing process of the piezoelectric vibrating piece 71 of the fourth embodiment, a quartz substrate having the same thickness as that of the vibrating portion 22 is prepared, and both sides of the quartz substrate are left as portions of the vibrating portion 22 and the second peripheral portion. Half-etching is performed until the thickness of 74 is reached, and half-etching is performed until the thickness of the mount portion 12, the buffer portion 14, and the first peripheral portion 72 is reached, leaving the vibrating portion 22 and the second peripheral portion 74, and the mount portion. 12, etching that penetrates the outer shape of the piezoelectric vibrating piece 71 except for the buffer portion 14 (slit 16) and the first peripheral portion 72. The subsequent electrode formation process is the same as that of the first embodiment.

  FIG. 14 shows the strength distribution of stress when stress (thermal strain) is applied to the mount portion of the piezoelectric vibrating piece of the present embodiment. The inventor of the present application performed a simulation on the stress intensity distribution when stress was applied to the mount portion of the piezoelectric vibrating piece of the present embodiment. The piezoelectric vibrating piece to be simulated is different from the piezoelectric vibrating piece of the second embodiment shown in FIG. 6 in that there is no step between the vibrating portion 22 and the second peripheral portion 62b. It has almost the same form. Therefore, in this simulation, description will be made corresponding to the piezoelectric vibrating piece 60 and its components in FIG.

  As shown in FIG. 14, the piezoelectric vibration when applying a pulling force or a pushing force to each other between two points at the positions of two points in the center of the two circles drawn on the mounting surface of the mount portion 12. The distribution of stress propagating on the surface of the piece 60 was simulated. 14 shows the strength (level 1 to level 9) of the stress received by the piezoelectric vibrating piece 60 due to the stress generated in the mount portion 12. Here, the level 9 indicates a region that receives the greatest stress, the stress received decreases from the level 9 region to the level 1 region, and the level 1 indicates a region where the received stress is the minimum or below the detection limit of the stress. Show. These patterns are drawn on the piezoelectric vibrating piece 60 corresponding to the stress intensity distribution of the piezoelectric vibrating piece 60.

  As shown in FIG. 14, it can be seen that strong stress (level 9) is generated on the entire mount portion 12 and on the mount portion 12 side of the buffer portion 14. The stress (level 9) generated on the mount portion 12 side is relaxed to about level 4 or 5 on the first peripheral portion 62a side of the slit 16. This is presumably because the stress propagating through the position around the slit 16 of the buffer portion 14 is relieved at a large rate during the propagation. Further, the stress propagated to the positions at both ends in the long side direction of the slit 16 of the buffer portion 14 is blocked by the notch 18 from the linear propagation path to the vibration portion 22, and the stress propagation path is constricted 20. It is considered that the stress was relieved at a large rate even during the propagation of this propagation path.

  At the boundary between the first peripheral edge 62a and the -Z'-axis side of the second peripheral edge 62b, the stress is predominantly level 5 on the first peripheral edge 62b side. Level 2 is dominant on the part 62b side, and the intensity of stress has a discontinuous change at this boundary. This is because the second peripheral edge portion 62b is formed thinner than the first peripheral edge portion 62a. Therefore, the second peripheral edge portion 62b is less affected by the stress propagated through the first peripheral edge portion 62a. Because it stays in receiving the department. Further, since there is a step between the second peripheral portion 62b and the first peripheral portion 62a, the stress propagation path is bent in the thickness direction of the piezoelectric vibrating piece 60 by this step, and the piezoelectric is generated by the bending of the path. This is because the stress propagating on the surface of the vibrating piece 60 is relaxed. Moreover, the 2nd peripheral part 62b (vibration part 22) is formed in the aspect dug from the surface where the conductive adhesive 32 of the mount part 12 is applied. This is because the stress also relaxes in the thickness direction of the piezoelectric vibrating piece 60, so that the second peripheral edge 62 b receives only a part of the stress relaxed in the thickness direction of the first peripheral edge 62 a. Of the first peripheral edge 62a, stress is hardly transmitted from the constricted portion 20 to the portion connected to the second peripheral edge 62b from the ± X-axis side, and from this portion to the second peripheral edge 62b. It can be said that there is almost no propagation of stress.

  In the second peripheral edge portion 62b, the stress level decreases as the distance from the boundary with the first peripheral edge portion 62a increases in the + Z′-axis direction, and the central portion of the second peripheral edge portion 62b in which the vibrating portion 22 is disposed. Then level 1 is dominant. In the piezoelectric vibrating piece 60 of the present embodiment, the vibrating portion 22 (excitation electrodes 24A and 24B) is disposed at the center position of the second peripheral edge portion 62b, so that the vibrating portion 22 is hardly affected by stress. Therefore, it is considered that good frequency characteristics can be obtained. Furthermore, in the second embodiment, since there is a step in the thickness direction between the second peripheral edge 62b and the vibrating portion 22, the stress propagating to the vibrating portion 22 is further relaxed by this step.

  The above-described simulation was performed for the case where the vibrating portion 22 was thinner than the peripheral edge 62 (first peripheral edge 62a). However, even if the vibrating portion 22 is thicker than the first peripheral portion 72 as in the third embodiment shown in FIG. 10, there is a step at the boundary between the vibrating portion 22 and the first peripheral portion 72. The stress propagating to the vibration part 22 is relieved by this step. Further, as in the fourth embodiment shown in FIG. 11, by using a two-stage mesa structure, the level difference is further increased, so that the stress propagating to the vibration part 22 can be further relaxed.

  The piezoelectric vibrating piece of the first embodiment and the second embodiment is an inverted mesa type piezoelectric vibrating piece in which the short side direction is the X-axis direction and the long side direction is the Z′-axis direction. The piezoelectric vibrating piece of the third and fourth embodiments is a mesa-type piezoelectric vibrating piece in which the short side direction is the Z′-axis direction and the long side direction is the X-axis direction. However, the present invention is not limited to this, and in the inverted mesa type piezoelectric vibrating piece, the short side direction may be the Z′-axis direction and the long side direction may be the X-axis direction. In the piece, the short side direction may be the X-axis direction and the long side direction may be the Z′-axis direction.

  FIG. 15 shows a piezoelectric vibrator on which the piezoelectric vibrating piece of this embodiment is mounted. FIG. 15A is a plan view of the piezoelectric vibrator 100 when the piezoelectric vibrating piece 60 shown in FIG. 6 is mounted, and FIG. 15B is a cross-sectional view taken along the line AA of FIG. The piezoelectric vibrator 100 is formed by a package 102 having a recess that accommodates the piezoelectric vibrating piece 60 and a lid 112 that seals the recess 104. An external electrode 106 is formed on the bottom surface of the bottom portion (mounting substrate 102a) of the package 102, and a connection electrode 110 electrically connected to the external electrode 106 through the through electrode 108 is disposed on the top surface of the mounting substrate 102a. Has been. The connection electrode 110 and the pad electrodes 28 </ b> A and 28 </ b> B of the mount portion 12 are joined by the conductive adhesive 32. Accordingly, the piezoelectric vibrating piece 60 is connected to the package 102 in a cantilevered state with the mount portion 12 as a fixed end. With the above configuration, the piezoelectric vibrator 100 in which the stress on the vibrating portion 22 of the piezoelectric vibrating piece 60 is relaxed is obtained. Furthermore, with the above configuration, the pad electrodes 28A and 28B (leading electrodes 26A and 26B) and the connection electrode 110 are bonded with the conductive adhesive 32, and the pad electrodes 28A and 28B and the connection electrode 110 are mechanically and electrically connected. By connecting, a so-called face-down bonding type mounting form can be adopted. Accordingly, it is possible to reduce the height of the piezoelectric vibrator 100 having a module structure including the piezoelectric vibrating piece 60 and the mounting substrate 102a.

  16 and 17 show a piezoelectric module on which the piezoelectric vibrating piece of this embodiment is mounted. 16 is an exploded perspective view of the piezoelectric module when the piezoelectric vibrating piece 60 shown in FIG. 6 is mounted. FIG. 17A is a cross-sectional view taken along the line AA in FIG. 12, and FIG. FIG. 16 is a cross-sectional view taken along line AA when the piezoelectric vibrating piece 61 shown in FIG. 9 is mounted. The piezoelectric module 200 according to this embodiment includes a package 202 (mounting substrate), piezoelectric vibrating pieces 60 and 61, an integrated circuit (IC 210) that drives the piezoelectric vibrating pieces 60 and 61 (see FIG. 9), and a lid. The package 202 is formed in a three-layer structure as indicated by a broken line in FIG. An external electrode 214 is formed on the lower surface of the package 202. A plurality of connection electrodes 216 are arranged on the lower step 206 of the recess 204 of the package 202. The upper portion 208 of the recess 204 of the package 202 is electrically connected to the pad electrode 220 of the IC 210, and the pad electrodes 28A and 28B of the piezoelectric vibrating reeds 60 and 61 (see FIGS. 6, 7, and 17). A connection electrode 218 connected through the conductive adhesive 32 is formed. A plurality of connection electrodes 216 are arranged corresponding to the pad electrodes 220 of the IC 210 and are electrically connected to the pad electrodes 220 by a conductive adhesive, but some of them are electrically connected to the connection electrodes 218 and the external electrodes 214. Connected. The piezoelectric module 200 of the present embodiment has a structure in which the piezoelectric vibrating reeds 60 and 61 and the IC 210 are both sealed by the lid 212 in the recess 204. With the above configuration, the piezoelectric module 200 in which the stress on the vibrating portion of the piezoelectric vibrating piece is relaxed is obtained.

  FIG. 18 shows a first modification of the piezoelectric module of the present embodiment. In FIG. 18, recesses 304 and 306 are formed on both surfaces of a package 302 (mounting substrate), the piezoelectric vibrating piece 60 is mounted in one recess 304 and sealed with a lid 308, and an integrated circuit is provided in the other recess 306. The piezoelectric module 300 has a configuration to which (IC316) is attached. An external electrode 310 is formed at the lower end of the package 302, and the recess 306 is electrically connected to the connection electrode 320 disposed in the external electrode 310 or the recess 304, and the pad electrode 318 of the IC 316 via the wire 314. A connection electrode 312 is provided for electrical connection. On the other hand, the connection electrode 320 disposed in the recess 304 is connected to the pad electrodes 28 </ b> A and 28 </ b> B of the piezoelectric vibrating piece 60 via the conductive adhesive 32. Therefore, the piezoelectric vibrating piece 60 is connected to the package in a cantilevered state with the mount portion 12 as a fixed end. By isolating the piezoelectric vibrating piece 60 and the IC 316 in this way, the influence of heat from the IC 316 of the piezoelectric vibrating piece 60 can be reduced.

  FIG. 19 shows a second modification of the piezoelectric module of the present embodiment. FIG. 19A is a side view, and FIG. 19B is a plan view of a substrate constituting the piezoelectric module. In the second modification, for example, the piezoelectric module 400 is formed using the piezoelectric vibrator 100 shown in FIG. That is, in the second embodiment, an electrode ball 412 that is electrically connected to the IC 404 (pad electrode 406) is disposed on the substrate 402 on which the integrated circuit (IC 404) that drives the piezoelectric vibrator 100 is mounted, and this electrode ball The piezoelectric vibrator 100 is supported by 412 and the electrode sphere 412 and the external electrode 106 of the piezoelectric vibrator 100 are electrically connected, and the substrate 402, the IC 404, the electrode sphere 412 and the piezoelectric vibrator 100 are made of a molding agent such as a resin. 416 is integrally formed. Here, an external electrode 410 is formed on the lower surface of the substrate 402, and a connection electrode 408 that is electrically connected to the external electrode 410 via the through electrode 418 is formed on the upper surface of the substrate 402. A part of the pad electrode 406 formed on the IC 404 is connected to the electrode ball 412 via the wire 414, and the rest is connected to the connection electrode 408 via the wire 414.

  With the above configuration, the substrate IC 404, the electrode sphere 412 and the like can be arranged in accordance with the standard of the existing piezoelectric vibrator 100 to form the piezoelectric module 400, so that the cost can be suppressed. In any embodiment, the connection between the IC and each electrode may be face-down bonding. In any of the embodiments of the piezoelectric vibrator and the piezoelectric module, this modification can be applied to the piezoelectric vibrating piece of any of the above-described embodiments.

  FIG. 20 shows a third modification of the piezoelectric module of the present embodiment. FIG. 20A is a schematic diagram of a piezoelectric module having a so-called H-shaped cross section, and FIG. 20B is a single seal type. The schematic diagram of this piezoelectric module is shown. In the third modified example, the piezoelectric vibrating piece 70 of the third embodiment (or other embodiments may be used) and a temperature sensing element that detects a temperature for exhibiting a function as a temperature sensor in the piezoelectric module 500 ( The thermistor 512) is mounted. In FIG. 20A, the mounting surface of the mount portion 12 of the piezoelectric vibrating piece 70 faces the mounting substrate 502 side, and the mount portion 12 and the connection electrode 504 arranged on the mounting substrate 502 are connected with the conductive adhesive 32. The piezoelectric module 500 is mounted with the piezoelectric vibrating piece 70 by bonding. On the mounting substrate 502, lids (side walls 506, lids 508) that cover the piezoelectric vibrating piece 70 are arranged. In addition, a recess 510 is disposed on the surface opposite to the surface facing the piezoelectric vibrating piece 70 of the mounting substrate 502. Further, the recess 510 has a thermistor 512 capable of measuring the temperature of the mounting substrate 502. With the above configuration, the temperature around the piezoelectric vibrating piece 70, that is, the temperature of the internal space that is closed by the mounting substrate 502 and the lid (side wall portion 506, lid 508) and seals the piezoelectric vibrating piece 70, By measuring the temperature of the bottom of the recess 510, the temperature of the internal space can be measured. Therefore, the piezoelectric module 500 capable of performing temperature compensation of the oscillation signal oscillated from the piezoelectric vibrating piece 70 with high accuracy. It becomes.

  Furthermore, with the above configuration, after the piezoelectric vibrating piece 70 is mounted on the mounting substrate 502 and before the temperature-sensitive element (thermistor 512) is mounted, the electrical characteristics and operating state of the piezoelectric vibrating piece 70 are inspected. Can do. Therefore, the non-defective product and the defective product can be selected in the piezoelectric vibrating piece 70 based on the inspection result of the piezoelectric vibrating piece 70. Therefore, since the temperature sensing element can be mounted only on the mounting substrate 502 on which a non-defective piezoelectric vibrating piece is omitted, the temperature sensing element is not wasted and the cost is reduced and the cost is reduced. Can be achieved.

  A piezoelectric module 501 shown in FIG. 20B is a piezoelectric module 501 similar to that shown in FIG. 20A, but a recess 514 is disposed on the surface of the mounting substrate 502 facing the piezoelectric vibration substrate 70. In the recess 514, a temperature sensitive element (thermistor 512) that is closed by the mounting substrate 502 and the lid (side wall portion 506, lid 508) and can measure the temperature of the internal space that seals the piezoelectric vibrating piece 70 is disposed. Has been. In FIGS. 20A and 20B, the thermistor 512 is mounted. However, the integrated circuit (IC 404) described above may be used, and it is preferable that the integrated circuit includes a temperature sensitive element such as a thermistor. is there.

10 ......... Piezoelectric vibrator element, 10a ......... Piezoelectric element plate, 12 ......... Mount part, 12a ......... Notch, 14 ......... Buffer part, 16 ......... Slit, 17 ...... Rim edge part, 17a ......... first peripheral portion, 17b ......... second peripheral portion, 18 ......... notch, 20 .... constricted portion, 22 ......... vibrating portion, 22a ......... concave portion, 24A, 24B ……… Excitation electrode, 26A, 26B ……… Extraction electrode, 28A, 28B ……… Pad electrode, 32 ……… Conductive adhesive, 34 ……… Mounting substrate, 36 ……… Quartz substrate, 38 …… ... Resist film, 38a ......... Resist film, 40 ...... Photo mask, 42 ......... Resist film, 42a ......... Resist film, 44 ...... Photo mask, 46 ...... Metal film, 48 ...... Resist film, 48a .... resist film, 50 .... photomask, 60 .... piezoelectric vibration Piece 61 ... Piezoelectric vibrating piece 62 ... Peripheral edge 62a ... First peripheral edge 62b ... Second peripheral edge 70 ... Piezoelectric vibrating piece 71 ... Piezoelectric Vibrating piece 72... First peripheral portion 74 74 Second peripheral portion 100 Piezoelectric vibrator 102 Package 102a Mounting substrate 104 Recessed portion 106... External electrode 108... Through electrode 110 110 Connection electrode 112 Lid 200 Piezoelectric module 202 Package 204 Recess 206 206 Lower stage, 208 ... Upper stage, 210 ... IC, 212 ... Lid, 214 ... External electrode, 216 ... Connection electrode, 218 ... Connection electrode, 220 ... Pad electrode, 300 ......... Piezoelectric module, 302 ......... Package, 304 ... Recess, 306 ......... Recess, 308 ......... Lid, 310 ... ... External electrode, 312 ... ... Connection electrode, 314 ... ... Wire, 316 ... ... IC, 318 ... ... Pad electrode, 320 ... ... Connection electrode, 400 ...... Piezoelectric module, 402 ...... Board, 404 ...... IC, 406 ...... Pad electrode, 408 ...... Connection electrode, 410 ...... External electrode, 412 ...... Electrode ball 414 ......... Wire, 416 ......... Molding agent, 418 ......... Penetration electrode, 500 ......... Piezoelectric module, 501 ......... Piezoelectric module, 502 ......... Mounting board, 504 ......... Connecting electrode, 506 ......... Side wall part, 508 ......... Lid, 510 ......... Recess, 512 ......... Thermistor, 514 ......... Recess, 600 ......... Piezoelectric vibrator, 602 ......... Supporting part, 604 ......... Vibration Part, 606A ......... Excitation electrode, 606B ......... Excitation electrode, 608A ......... Input / output terminal portion, 608B ......... Input / output terminal portion, 610 ......... Slit, 612 ......... Container, 614 ......... Bottom portion, 616 ......... Adhesive, 700 ......... Piezoelectric vibrating piece, 702 ......... Mount part, 704 ......... Slit, 706 ......... Vibrating part, 708 ......... Notch, 710 ...... Connecting part.

Claims (8)

On the piezoelectric substrate,
A vibration part for exciting thickness shear vibration;
A peripheral portion having a thickness smaller than a thickness of the vibrating portion at a peripheral portion of the vibrating portion;
A piezoelectric vibrating piece provided with
A buffer portion and a mount portion are sequentially connected to the peripheral portion,
The buffer portion has a slit between the mount portion and the peripheral portion,
The mount part is
A piezoelectric vibrating piece having notches at both ends in a direction orthogonal to a direction in which the mount portion, the buffer portion, and the peripheral portion are arranged.   2. The piezoelectric vibrating piece according to claim 1, wherein the connecting portion between the buffer portion and the peripheral portion has a notch. Regarding the direction orthogonal to the direction in which the mount part, the buffer part and the peripheral part are arranged,
The width of the peripheral edge is
The piezoelectric vibrating piece according to claim 1, wherein the piezoelectric vibrating piece is narrower than a width of the buffer portion. The piezoelectric substrate is
Centered on the X axis of the orthogonal coordinate system consisting of the crystal axis of quartz, the X axis as the electrical axis, the Y axis as the mechanical axis, and the Z axis as the optical axis,
An axis obtained by inclining the Z axis in the −Y direction of the Y axis is defined as a Z ′ axis.
An axis obtained by inclining the Y axis in the + Z direction of the Z axis is defined as a Y ′ axis.
It is composed of a plane parallel to the X axis and the Z ′ axis,
4. The piezoelectric vibrating piece according to claim 1, wherein the piezoelectric vibrating piece is a quartz substrate having a thickness in a direction parallel to the Y ′ axis. The peripheral portion is
A first peripheral edge connected to the buffer;
A second peripheral portion disposed on the periphery of the vibrating portion and connected to the first peripheral portion;
The thickness of the second peripheral edge is
The piezoelectric vibrating piece according to claim 1, wherein the piezoelectric vibrating piece is thicker than a thickness of the first peripheral edge. Excitation electrodes are respectively arranged on both main surfaces of the front and back of the vibration part,
6. The piezoelectric vibrating piece according to claim 5, wherein a pair of extraction electrodes electrically connected to the excitation electrodes are disposed on a mounting surface of the mount portion. A piezoelectric module in which the piezoelectric vibrating reed is mounted by adhering the mounting portion of the piezoelectric vibrating reed according to any one of claims 1 to 6 to a connection electrode disposed on a mounting substrate with a conductive adhesive. And
A lid that covers the piezoelectric vibrating piece is disposed on the mounting substrate,
A recess is disposed on a surface of the mounting substrate that faces the piezoelectric vibration substrate,
The piezoelectric module according to claim 1, wherein a temperature sensitive element capable of measuring the temperature of the internal space closed by the mounting substrate and the lid is disposed in the recess. A piezoelectric module in which the piezoelectric vibrating reed is mounted by adhering a mounting portion of the piezoelectric vibrating reed according to any one of claims 1 to 6 and a connection electrode disposed on a mounting substrate with a conductive adhesive. Because
A lid that covers the piezoelectric vibrating piece is disposed on the mounting substrate,
A concave portion is disposed on a surface of the mounting substrate opposite to the surface facing the piezoelectric vibration substrate, and a thermosensitive element capable of measuring the temperature of the mounting substrate is disposed in the concave portion. .