JP2012186639A - Piezoelectric vibrating piece, piezoelectric vibrator, and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric vibrating piece that relaxes stress on a vibrating portion when mounted, and to provide a piezoelectric vibrator using the same.SOLUTION: A piezoelectric vibrating piece 10 is formed of an AT-cut quartz crystal, and includes: a thin portion 21 that has a vibrating portion 22; and a thick portion 17 that is located on each edge of the piezoelectric vibrating piece 10 and that is thicker than the thin portion 21. Given that an angle formed by rotating a +Z'-axis in a direction of a +X-axis about a Y'-axis is a positive rotation angle, the piezoelectric vibrating piece 10 has edges that are respectively parallel to a Z''-axis obtained by rotating the Z'-axis in a range of -120° to +60° about the Y'-axis and to an X'-axis obtained by rotating the X-axis along with the Z'-axis about the Y'-axis. To the thick portion 17, a mount portion 12 is connected side by side through a cushioning portion 14 in a direction of one of the edges. The cushioning portion 14 has a slit 16 between the mount portion 12 and the thick portion 17. The mount portion 12 has a chamfered portion 18 on each side in a perpendicular direction to a direction in which the mount portion 12, the cushioning portion 14, and the thick portion 17 are aligned. At least a part of the slit 16 in a longitudinal direction is parallel to the perpendicular direction.

Description

  The present invention relates to a piezoelectric vibrating piece, a piezoelectric vibrator using the same, and an electronic device, and more particularly to a technique for mitigating the influence of stress on a vibrating part 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, the mount distortion, adversely affects the vibration region.

  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 There is a problem in that the area must be reduced, and thereby the problem that the electrical characteristics of the piezoelectric vibrator are deteriorated appears remarkably. For example, the problem that impedance becomes large and good characteristics cannot be obtained appears remarkably.

Therefore, in view of such a problem, in Patent Document 12, 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. 19 is a schematic diagram of a piezoelectric vibrator according to Patent Document 12. FIG. 19A is a top view of the piezoelectric vibrating piece constituting the piezoelectric vibrator, FIG. 19B is a bottom view of the piezoelectric vibrating piece constituting the piezoelectric vibrator, and FIG. FIG. 19D is a cross-sectional view taken along the line AA ′ of FIG. 19C.

  In FIG. 19, a rectangular piezoelectric vibrator 600 having a support portion 602 and a vibrating portion 604 is shown. The excitation electrode portions 606A and 606B formed on the upper surface and the lower surface of the vibration portion 604 of the piezoelectric vibrator 600, respectively, and the support electrode 602 (of the piezoelectric vibrator 600) are pulled out from the excitation electrode portions 606A and 606B. A slit 610 is disposed and formed on the main surface of the piezoelectric vibrator 600 between the input / output terminal portions 608A and 608B. Thus, the excitation electrode portions 606A and 606B are physically separated from the input / output terminal portions 608A and 608B.

  In the above configuration, when the adhesive 616 for fixing and electrically connecting the support portion 602 of the piezoelectric vibrator 600 and the electrode terminal (not shown) at the bottom of the container 612 containing the piezoelectric vibrator 600 is cured. In the direction and range shown 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. In addition, as a similar technique, a slit (see Patent Documents 1 to 5) or a notch (see Patent Documents 1, 2, 3, 4, 6, 7, and 8) between the portion where the conductive adhesive is applied and the vibration part. ) Is disclosed. Further, 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 9 to 11).

  In the above patent document, the propagation of the stress generated on the mount side of the piezoelectric vibrating piece to the vibration part side is structurally reduced, but the technique of reducing the stress propagating to the vibration part side from the physical point of view. Has also been proposed. That is, in Patent Document 13 and Patent Document 14, the surface orientation of the long side and the short side of a piezoelectric vibrating piece using a so-called AT-cut quartz substrate is designed in a direction in which the stress sensitivity is reduced. .

  In Patent Document 13, the Z′-axis and X′-axis obtained by rotating the Z′-axis and the X-axis on the cut surface of the AT-cut quartz substrate about 30 ° in the + X-axis direction around the Y′-axis are respectively parallel. A piezoelectric vibrating piece having a simple edge is employed.

  Here, Non-Patent Document 1 describes the stress sensitivity related to the AT-cut quartz substrate. In the AT-cut quartz substrate, the X axis is rotated around the Y ′ axis in the direction from the −X axis to the −Z ′ axis. It is described that the stress sensitivity is most dull in the direction of the Z ″ axis obtained by rotating the Z ′ axis by rotating the angle by 120 ° or 120 °.

  Therefore, in Patent Document 14, based on the research results of Non-Patent Document 1 regarding mount distortion (stress sensitivity) caused by the substrate of the resonator element (AT-cut quartz substrate), it is further excellent in mass productivity and vibration with respect to the resonator element. Z ′ obtained by rotating the Z ′ axis and the X axis around the Y ′ axis in the range of −120 ° to + 60 ° in the + X axis direction for the purpose of increasing the occupation ratio of the portion, that is, the thin portion. A piezoelectric vibrating piece is employed in which the direction of the long side of the thin portion having edges parallel to the axis and the X ′ axis is aligned with the Z ″ axis.

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 Japanese Patent Laid-Open No. 9-326667 Japanese Patent No. 4310838 JP 2009-164824 A

J. et al. M.M. Ratajski, “The Force Sensitivity of AT-Cut Quartz Crystals”, 20th Annual Symposium on Frequency Control, (1966)

  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. 20 shows the stress distribution when a slit is formed between the mounting portion and the vibrating portion of the piezoelectric vibrating piece. FIG. 20A shows the case where the width of the slit of the piezoelectric vibrating piece in the Z′-axis direction is 150 μm. FIG. 20B shows the stress distribution when the width of the slit of the piezoelectric vibrating piece in the Z′-axis direction is 250 μm. 21 and 22, a connecting portion that connects the mount portion and the vibrating portion by forming a notch at a position between the mount portion and the vibrating portion on both sides in the width direction of the piezoelectric vibrating piece. FIG. 21A shows the stress distribution when the width of the connecting portion in the X-axis direction is 400 μm, and FIG. 21B shows the width of the connecting portion in the X-axis direction of 300 μm. 22A shows the stress distribution when the width of the connecting portion in the X-axis direction is 200 μm, and FIG. 22B shows the stress when the width of the connecting portion in the X-axis direction is 100 μm. Show the distribution.

  20, 21, and 22 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 thermal strain applied to the piezoelectric vibrating piece due to differences in the thermal expansion coefficients of the piezoelectric vibrating piece, the conductive adhesive, and the substrate.

  20, 21, and 22, 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. 17, 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 aligned (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 part 702 side to the end of the mount part 702 is 350 μm in FIG. 20A and 250 μm in FIG. The width of the slit 704 in the Z′-axis direction is 150 μm in FIG. 20A and 250 μm in FIG. That is, in FIG. 20A and FIG. 20B, the position and width of the slit 704 in the Z′-axis direction are changed.

  20, 21, and 22, the plurality of patterns arranged in a vertical line on the left indicate the strength of the 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. 20, in such a small piezoelectric vibrating piece 700, even if the slit 16 is formed or the position or width of the slit 16 is changed, it is caused by the thermal strain generated in the mount portion 12. It can be seen that the strong stress reaches the vibrating portion 706 of the piezoelectric vibrating piece 700 without completely eliminating the stress. 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 FIG. 21 and FIG. 22 has 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, a piezoelectric vibrator, and an electronic device that can sufficiently relax 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 crystal axis of quartz, an X axis as an electric axis, a Y axis as a mechanical axis, and a Z axis as an optical axis, and the X axis of an orthogonal coordinate system as a rotation axis, An axis obtained by rotating the Z axis in the −Y direction of the Y axis is a Z ′ axis, an axis obtained by rotating the Y axis in the + Z direction of the Z axis is a Y ′ axis, and the X axis and the Z ′ It is composed of a plane parallel to the axis and is formed of an AT-cut crystal having a thickness in the direction parallel to the Y ′ axis, and is provided on the periphery of the thin portion and the thin portion, and is thicker than the thin portion. A piezoelectric vibrating piece having a thick wall portion, wherein the piezoelectric vibrating piece has the Z ′ axis as the positive rotation angle by rotating the + Z ′ axis around the Y ′ axis in the + X axis direction. The Z ″ axis obtained by rotating the Y ′ axis in the range of −120 ° to + 60 °, and the X axis around the Y ′ axis And the X ′ axis obtained by rotating together with the Z ′ axis, respectively, and the mount portion is connected side by side via a buffer portion in the direction of the edge, to the thick portion, The buffer portion has a slit between the mount portion and the thick portion, and the mount portion has both ends orthogonal to the direction in which the mount portion, the buffer portion, and the thick portion are arranged. The piezoelectric vibrating piece according to claim 1, further comprising a chamfered portion, wherein at least a part of a longitudinal direction of the slit is parallel to the orthogonal direction.

  The piezoelectric vibrating piece is connected to the substrate by applying a conductive adhesive to the mount portion. However, this causes thermal distortion between the mount portion and the conductive adhesive, which propagates as stress throughout the piezoelectric vibrating piece. However, the chamfered portion formed in the mount portion reduces the width of the mount portion. Thereby, since the distance between the conductive adhesives bonded to the mount portion is shortened, the stress itself generated between the conductive adhesive and the mount portion can be reduced. In addition, the stress that is generated between the mount portion and the conductive adhesive and propagates to the vibration portion side has the largest component that proceeds straight toward the vibration portion side. However, since the slit is arranged on the straight path through which stress is most strongly propagated, the straight path is blocked and only the stress component that bypasses the slit can propagate to the vibrating part side. . However, since the stress is bent every time it travels to the vibration part side, the stress is relieved at a large rate. Accordingly, the piezoelectric vibration piece is sufficiently relaxed before the stress is propagated to the vibration part, and the influence of the stress on the vibration part can be reduced.

  Also, by using an AT-cut quartz substrate, a piezoelectric vibrating piece capable of efficiently oscillating thickness shear vibration is obtained. By designing the direction of the edge of the piezoelectric vibrating piece as described above, the stress transmitted to the vibrating part side can be reduced by suppressing the stress sensitivity of the entire piezoelectric vibrating piece, and the influence of the stress on the vibrating part The piezoelectric vibrating piece is reduced.

Application Example 2 In the piezoelectric vibrating piece according to Application Example 1, the direction in which the thick portion, the buffer portion, and the mount portion are arranged is an edge direction parallel to the Z ″ axis.
Stress due to thermal distortion in the piezoelectric vibrating piece is generated in the width direction of the mount portion starting from the conductive adhesive applied to the mount portion, and propagates to the vibration portion side. However, with the above configuration, the stress sensitivity to the stress propagating in the Z ″ axis direction is reduced, so that the component of the generated stress propagating to the vibrating portion side can be reduced. Therefore, the piezoelectric vibrating piece is reduced in the influence of stress on the vibrating portion.

Application Example 3 The piezoelectric vibrating piece according to Application Example 1, wherein the thick portion, the buffer portion, and the mount portion are arranged in the direction of the edge parallel to the X ′ axis.
Stress due to thermal distortion in the piezoelectric vibrating piece is generated in the width direction of the mount portion starting from the conductive adhesive applied to the mount portion, and propagates to the vibration portion side. However, with the above configuration, the stress sensitivity to the stress propagating in the Z ″ axis direction is reduced, and therefore the stress itself generated in the mount portion 12 can be reduced. Therefore, the piezoelectric vibrating piece is reduced in the influence of stress on the vibrating portion.

[Application Example 4] Application examples 1 to 2, characterized in that both ends of the slit in the longitudinal direction are bent or curved so as to be positioned closer to the mount portion than the center in the longitudinal direction of the slit. 4. The piezoelectric vibrating piece according to any one of 3 examples.
With the above configuration, since the slit surrounds the stress generated in the mount portion during mounting, the leakage of stress to the thin portion side can be reduced, and the influence of the stress on the vibration portion can be reduced.

Application Example 5 The piezoelectric vibrating piece according to any one of Application Examples 1 to 4, wherein a reinforcing portion formed in a thin wall is disposed at each of the both end portions of the slit.
With the above configuration, the strength of the buffer portion can be ensured without impairing the effect of limiting the propagation of stress to the vibrating portion side of the slit.

Application Example 6 The slit has a shape that is bent or curved so that both end portions in the longitudinal direction of the slit are located on the side of the thin portion with respect to the central portion in the longitudinal direction of the slit, 4. The piezoelectric vibrating piece according to any one of application examples 1 to 3, wherein a groove is formed at a position sandwiched from both ends in the longitudinal direction.
With the above configuration, the slit has a shape in which the stress generated in the mount portion during mounting is received to some extent on both ends of the slit, but the received stress can be blocked by the groove. As a result, the stress generated in the mount part is equalized on the mount part and the mount part side of the slit of the buffer part. Therefore, it is possible to suppress the variation in the stress distribution when the piezoelectric vibrating piece is mass-produced, thereby suppressing the variation in the characteristics such as the frequency characteristic of the piezoelectric vibrating piece, thereby reducing the cost.

Application Example 7 Excitation electrodes for vibrating the vibration unit are formed on both surfaces of the vibration unit, and a pair of lead electrodes electrically connected to the excitation electrodes are formed on the mounting surface of the mount unit. The piezoelectric vibrating piece according to any one of Application Examples 1 to 6, wherein the thin-walled portion is connected to the thick-walled portion while being biased toward the opposite surface of the mounting surface.
With the above configuration, a step is formed in the thickness direction at the boundary on the mounting surface side between the thin portion and the thick portion. Therefore, since the distance between the conductive adhesive applied to the extraction electrode and the vibration part is increased by the above-described step, the stress reaching the vibration part can be more relaxed.

Application Example 8 The piezoelectric vibrating piece according to any one of Application Examples 1 to 7, wherein the vibration part is formed thicker than the thin part.
With the above configuration, the thickness shear vibration can be confined to the vibration part, and the excitation efficiency can be increased.

Application Example 9 Having a substrate, the mounting surface of the mounting portion of the piezoelectric vibrating piece according to any one of Application Examples 1 to 8 is directed toward the substrate side, the pair of connection portions of the mount portion, A piezoelectric vibrator in which the piezoelectric vibrating piece is mounted by bonding a pair of portions of the substrate facing a pair of connecting portions using a bonding member.
With the above configuration, a piezoelectric vibrator in which stress on the vibration part is relaxed is obtained.

Application Example 10 The piezoelectric vibrator according to Application Example 9, wherein a direction connecting the pair of connection portions is parallel to the X ′ axis or the Z ″ axis.
With the above configuration, a piezoelectric vibrator in which stress on the vibrating portion is further relaxed is obtained.

Application Example 11 Having a substrate, the mounting surface of the mounting portion of the piezoelectric vibrating piece according to any one of Application Examples 1 to 8 is directed to the substrate side, and a pair of connection portions of the mount portion; An electronic device comprising: at least one or more electronic components, wherein the piezoelectric vibrating reed is mounted by bonding with a pair of portions of the substrate facing the pair of connection portions using a bonding member.
With the above configuration, an electronic device in which stress on the vibration part is relaxed is obtained.

Application Example 12 The electronic device according to Application Example 11, wherein a direction connecting the pair of connection portions is parallel to the X ′ axis or the Z ″ axis.
With the above configuration, an electronic device in which stress on the vibration part is further relaxed is obtained.

Application Example 13 In the electronic device according to Application Example 11 or 12, the electronic component is any one of a thermistor, a capacitor, a reactance element, and a semiconductor element.
With the above configuration, an electronic device using the piezoelectric vibrating piece as an oscillation source can be constructed.

It is a schematic diagram of the piezoelectric vibrating piece according to the first embodiment, FIG. 1A is a top view, FIG. 1B is a bottom view, and FIG. 1C is a diagram showing 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 first side view, FIG. 2B is a second side view, and FIG. 2C is A in FIG. -A sectional view, FIG.2 (d) is BB sectional drawing of Fig.1 (a). It is a figure which shows the manufacturing process (thin wall part formation process) of the piezoelectric vibrating piece which concerns on 1st Embodiment. It is a figure which shows the manufacturing process (outer shape formation process) of the piezoelectric vibrating piece which concerns on 1st Embodiment. It is a figure which shows the manufacturing process (electrode formation process) of the piezoelectric vibrating piece which concerns on 1st Embodiment. 6A and 6B are schematic views of a piezoelectric vibrating piece according to a second embodiment, in which FIG. 6A is a top 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 line B-B in FIG. FIG. 7A is a schematic view of a modification of the piezoelectric vibrating piece according to the second embodiment, FIG. 7A is a top view, FIG. 7B is a bottom view, and FIG. 7C is an A- in FIG. FIG. 7D is a cross-sectional view taken along line A, and FIG. 7D is a cross-sectional view taken along line BB in FIG. FIG. 8A is a schematic view of a piezoelectric vibrating piece according to a third embodiment, FIG. 8A is a plan view, and FIG. 8B is a bottom view. FIG. 9A is a schematic view of a modification of the piezoelectric vibrating piece according to the third embodiment, FIG. 9A is a top view, and FIG. 9B is a bottom view. FIG. 10A is a schematic view of a piezoelectric vibrating piece according to a fourth embodiment, FIG. 10A is a top view, and FIG. 10B is a bottom view. FIG. 11A is a schematic view of a piezoelectric vibrating piece according to a fifth embodiment, FIG. 11A is a top view, and FIG. 11B is a bottom view. FIG. 12A is a schematic view of a modification of the piezoelectric vibrating piece according to the fifth embodiment, FIG. 12A is a top view, and FIG. 12B is a bottom view. 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. 14A is a schematic diagram of a piezoelectric vibrator on which the piezoelectric vibrating piece according to the present embodiment is mounted. FIG. 14A is a top view of the piezoelectric vibrator when the piezoelectric vibrating piece shown in FIG. 6 is mounted, and FIG. It is the sectional view on the AA line of Fig.14 (a). It is a disassembled perspective view of the electronic device carrying the piezoelectric vibrating piece shown in FIG. FIG. 16A is a schematic diagram of an electronic device on which the piezoelectric vibrating piece of the present embodiment is mounted, and FIG. 16A is a cross-sectional view taken along line AA when the piezoelectric vibrating piece shown in FIG. 16B is a cross-sectional view taken along line AA in FIG. 15 when the piezoelectric vibrating piece shown in FIG. 7 is mounted. It is a schematic diagram of the 1st modification of the electronic device of this embodiment. It is a schematic diagram of the 2nd modification of the electronic device of this embodiment. FIG. 19A is a schematic diagram of a piezoelectric vibrator according to Patent Document 12, FIG. 19A is a top view of a piezoelectric vibrating piece constituting the piezoelectric vibrator, and FIG. 19B is a bottom face of the piezoelectric vibrating piece constituting the piezoelectric vibrator. FIG. 19C is a top view of the piezoelectric vibrator in which the piezoelectric vibrating piece is mounted inside the container, and FIG. 19D is a cross-sectional view taken along the line AA ′ of FIG. 19C. FIG. 20A shows the stress distribution when a slit is formed between the mount portion and the vibrating portion of the piezoelectric vibrating piece. FIG. 20A shows the stress distribution when the slit width of the piezoelectric vibrating piece is 150 μm. FIG. ) 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. 21A shows the stress distribution when the width of the connecting portion is 400 μm, and FIG. 21B 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. 22A shows the stress distribution when the width of the connecting portion is 200 μm, and FIG. 22B 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 for the following description, it is assumed that the X ′ axis, the Y ′ axis, and the Z ″ axis are orthogonal to each other.

  The piezoelectric vibrating piece according to the first embodiment is shown in FIGS. 1 (a) is a top 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 first side view, and FIG. FIG. 2C is a sectional view taken along line AA in FIG. 1A, and FIG. 2D is a sectional view taken along line BB in FIG. As shown in FIG. 1C, the piezoelectric vibrating piece 10 according to the present embodiment includes, as the piezoelectric element plate 11, an X axis as an electric axis, which is a crystal axis of quartz, a Y axis as a mechanical axis, Centering on the X axis of the orthogonal coordinate system consisting of the Z axis as an optical axis, the Z axis is tilted in the −Y direction of the Y axis as the Z ′ axis, and the Y axis is the Z axis. An AT-cut quartz crystal substrate 11a is used, which is composed of a plane parallel to the X-axis and the Z'-axis, with the axis tilted in the + Z direction as the Y'-axis and having a thickness in the direction parallel to the Y'-axis. . As a result, the piezoelectric vibrating piece 10 capable of efficiently oscillating thickness shear vibration is obtained.

  Furthermore, the piezoelectric vibrating reed 10 of this embodiment has a positive rotation angle of rotating the + Z ′ axis around the Y ′ axis in the + X axis direction on the AT-cut quartz substrate 11a, and the Z ′ axis around the Y ′ axis. The direction parallel to the Z ″ axis obtained by rotating within a range of angle ψ (−120 ° to + 60 °) is the long side (edge), and the X axis is rotated around the Y ′ axis together with the Z ′ axis. The obtained rectangular piezoelectric element 11 having a rectangular shape with a short side (edge) parallel to the X ′ axis is used. That is, the piezoelectric element plate 11 that forms the outer shape of the piezoelectric vibrating piece 10 is obtained by rotating the in-plane orientation of the AT-cut quartz crystal substrate 11 a by the angle ψ.

  In addition, the piezoelectric vibrating piece 10 has a reverse mesa having a thin portion 21 (vibrating portion 22) formed to be thinner than the thick portion 17 by wet etching with a thick portion 17 (reinforcing portion) left at the periphery. The structure has a vibrating portion 22 of a mold. The piezoelectric vibrating piece 10 has a configuration in which the mount portion 12, the buffer portion 14, and the thick portion 17 (vibrating portion 22) are connected side by side in order along the long side direction (Z ″ axis direction). . That is, the buffer part 14 is formed between the mount part 12 and the thick part 17. The piezoelectric vibrating piece 10 has a line-symmetric shape with the AA line in FIG. The piezoelectric vibrating reed 10 having the above outer shape is fixed to the mounting substrate 34 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 the end portion on the + Z ″ axis side of the piezoelectric vibrating piece 10, and chamfered portions 18 are formed at both ends in the X ′ axis direction. Among the four corners of the piezoelectric vibrating piece 10 having a rectangular shape, the chamfered portion 18 includes a long side and a short side of the piezoelectric vibrating piece 10 that form the two corners at two corners included in the mount portion 12, respectively. Two intersecting diagonal lines are used as cut surfaces, and the two corners are cut in a manner cut off. In addition, as shown in FIG. 1, the chamfered part 18 may form the chamfered part 18a in a curved line instead of cutting the mount part 12 linearly from an oblique direction.

  Pad electrodes 26a and 30a that are electrically connected to excitation electrodes 24 and 28 (described later) via lead electrodes 26 and 30 are arranged on one main surface (the surface on the −Y′-axis side) of the mount portion serving as a mounting surface. Has been. The pad electrodes 26a and 30a are coated with a conductive adhesive 32 that serves as a bonding member to be bonded to the mounting-side substrate 34, and the pad electrodes 26a and 30a are bonded to portions (for example, connection electrodes) on the mounting-side substrate 34. . Therefore, a piezoelectric vibrator is formed by bonding to the substrate 34 using the conductive adhesive 32. Further, the position where the conductive adhesive 32 is applied in the mount portion 12 becomes a pair of connection portions, and the direction in which the connection portions are arranged is a direction parallel to the X ′ axis.

  The buffer portion 14 is a region that is disposed between the mount portion 12 and the thick portion 17 and relieves stress generated in the mount portion 12 and propagating to the vibrating portion 22 side. In order to realize this, the buffer part 14 is provided with a slit 16. The slit 16 is formed as a rectangular through hole having a longitudinal direction in the X′-axis direction and penetrating in the thickness direction (Y′-axis direction) of the piezoelectric vibrating piece 10. As a result, connecting portions 15 that connect the thick portion 17 and the mount portion 12 are formed at both ends of the buffer portion 14 in the X′-axis direction. The buffer portion 14 side of the mount portion 12 and the mount portion 12 side of the buffer portion 14 are integrally formed. As shown in FIGS. 1 (a) and 1 (b), the above-described extraction electrodes 26 and 30 are also formed in the buffer portion 14 (connection portion 15).

  The thin-walled portion 21 is formed by thinning a part of the thick-walled portion 17 and is formed so as to be dug from the mounting surface (the surface on the −Y′-axis side) of the mount portion 12. Thereby, the thin portion 21 is unevenly distributed on the surface of the thick portion 17 on the + Y′-axis side and connected to the thick portion 17, and the thin portion 21 and the thick portion 17 are connected to the −Y ′ axis of the piezoelectric vibrating piece 10. A step is formed on the side surface. Further, the ± X ′ axis side and the + Z ″ axis side of the thin portion 21 are in contact with the thick portion 17, but the −Z ″ axis side of the thin portion 21 is −Z ″ of the piezoelectric vibrating piece 10. It is a part of the end on the shaft side.

  The vibration part 22 constitutes a part of the thin-walled part 21 and is a region that generates thickness shear vibration in the piezoelectric vibrating piece 10. Excitation electrodes 24 and 28 are formed on both the main surfaces (front and back surfaces) of the center of the vibrating portion 22 so as to face each other. The excitation electrode 28 formed on the surface on the + Y ′ axis side is connected to the extraction electrode 30, and the excitation electrode 24 formed on the surface on the −Y ′ axis side is electrically connected to the extraction electrode 26. The extraction electrode 26 is connected to a pad electrode 26 a disposed on the mount portion 12 via the surfaces of the thin portion 21, the thick portion 17, and the buffer portion 14 (connecting portion 15). The extraction electrode 30 is connected to the pad electrode 30a disposed on the mount portion 12 via the surface of the thin portion 21, the surface and end surface of the thick portion 17, and the surface of the buffer portion 14 (connecting portion 15). Therefore, by applying an AC voltage to the pad electrodes 26a and 30a, 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 decreases after bonding, the piezoelectric resonator element 10, the substrate 34, and the conductive adhesive 32 have different thermal expansion coefficients in the region connecting the two points where the conductive adhesive 32 of the mount 12 is applied. Thermal distortion occurs, and stress resulting from this is propagated throughout the piezoelectric vibrating piece 10.

  However, due to the chamfered portion 18 formed in the mount portion 12, the width of the mount portion 12 in the X'-axis direction becomes narrower as it goes in the + Z "-axis direction. Thereby, since the distance between the conductive adhesives 32 bonded to the mount portion 12 is shortened, the stress itself generated between the conductive adhesive 32 and the mount portion 12 can be reduced. In addition, the stress generated between the mount portion 12 and the conductive adhesive 32 and propagated to the vibrating portion 22 side is a component that propagates straight toward the vibrating portion 22 side (a component that travels in the −Z ″ axis direction). Is the largest. However, since the slit 16 is arranged on the straight path through which stress is most strongly propagated, the straight path is blocked and only the stress component that bypasses the slit 16 and propagates through the connecting portion 15 is obtained. Can propagate to the vibrating portion 22 side. However, since the stress is bent every time it travels to the vibrating portion 22 side, the stress is relieved at a large rate. Therefore, the stress is sufficiently relaxed before the stress is propagated to the vibrating portion 22, and the piezoelectric vibrating piece 10 is obtained that can relax the influence of the stress on the vibrating portion 22.

  In addition, when a stress is applied to the vibration unit 22 from the outside, the apparent rigidity of the vibration unit 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, as described above, the strain generated in the mount portion 12 is alleviated in the slit 16, thereby suppressing the frequency fluctuation and increasing the yield of the piezoelectric vibrator using the same.

  Furthermore, the vibration part 22 is formed thinner than the buffer part 14. Thereby, since the stress which the vibration part 22 receives from the buffer part 14 becomes small, the influence of the stress to the vibration part 22 can be relieved. As shown in FIG. 1, the vibrating portion 22 is formed by digging by half etching from the surface side (the surface side on the −Y ′ axis side) to which the conductive adhesive 32 is applied. Therefore, the connection position between the vibration part 22 and the buffer part 14 is the surface opposite to the surface (the surface on the −Y′-axis side) on which the pad electrodes 26 a and 30 a of the piezoelectric vibrating piece 10 are disposed (the surface on the + Y′-axis side). In this state, a step is formed between the vibrating portion 22 and the thick portion 17. Therefore, since the distance from the conductive adhesive 32 applied to the pad electrodes 26a and 30a is increased by the above-described step difference, the stress reaching the vibration part 22 can be more relaxed.

  Further, the stress due to the thermal strain in the piezoelectric vibrating piece 10 is caused by the width direction (X ′ axis) of the mount portion 12 starting from a pair of portions (a pair of connection portions) coated with the conductive adhesive 32 of the mount portion 12. Direction) and propagates to the vibrating portion 22 side. However, in this embodiment, since the stress sensitivity to the stress propagating in the Z ″ axis direction is reduced, the long side of the piezoelectric vibrating piece 10 is the Z ″ axis direction and the short side is the X ′ axis direction. Thereby, the component which propagates to the vibration part 22 side among the stress which generate | occur | produced in the mount part 12 (between connection parts) can be reduced. Accordingly, the piezoelectric vibrating piece 10 is obtained in which the influence of stress on the vibrating portion 22 is reduced.

  In the piezoelectric vibrating piece 10 of the present embodiment, the reverse mesa type piezoelectric vibrating piece 10 is configured so that the short side direction is the X′-axis direction and the long side direction is the Z ″ -axis direction. However, the present invention is not limited to this, and the reverse mesa type piezoelectric vibrating piece 10 may be configured such that the short side direction of the piezoelectric vibrating piece 10 is the Z′-axis direction and the long side direction is the X′-axis direction. In this case, the stress due to the thermal strain in the piezoelectric vibrating piece 10 is caused by the width direction (Z ′) of the mount portion 12 starting from a pair of portions (a pair of connection portions) to which the conductive adhesive 32 of the mount portion 12 is applied. ('Axis direction) and this propagates to the vibrating portion 22 side. However, since the stress sensitivity to the stress propagating in the Z ″ axis direction is reduced, the stress itself generated in the mount portion 12 can be reduced. Accordingly, the piezoelectric vibrating piece 10 is obtained in which the influence of stress on the vibrating portion 22 is reduced.

Next, the manufacturing process of the piezoelectric vibrating piece 10 of the first embodiment will be described.
FIG. 3 shows a manufacturing process (thin wall 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, a position corresponding to the thin-walled portion 21 (vibrating portion 22) is half-etched in the quartz substrate 36 that is a material of the piezoelectric vibrating piece 10, and is etched according to the outer shape of the piezoelectric vibrating piece 10, thereby exciting electrodes. 24 and 28, extraction electrodes 26 and 30, and pad electrodes 26a and 30a are formed.

  As shown in FIG. 3, first, the outer shape of the thin portion 21 (vibrating portion 22) 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 element plate, 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 thin portion 21, and the exposed resist film 38a is removed as shown in FIG. 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 thin portion 21, and the resist film 38 is removed as shown in FIG. At this time, a concave portion 21 a corresponding to the thin portion 21 is formed in the quartz substrate 36.

  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 21a are formed. 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 chamfered portion 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 (including the slit 16 and the chamfered portion 18) 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 resist film 48 is exposed using a photomask 50 corresponding to the shapes of the excitation electrodes 24 and 28, the extraction electrodes 26 and 30 and the pad electrodes 26a and 30a on both surfaces of the piezoelectric vibrating piece 10. To do. At this time, the portion of the resist film 48 that passes through the end face of the extraction electrode 30 is not exposed. Next, the exposed resist film 48a is removed as shown in FIG. 5D, and the excitation electrodes 24 and 28 and the extraction electrodes 26 and 30 (not shown in FIG. 5) correspond to the resist film 48a as shown in FIG. Etching is performed with the metal film 46 other than the portion 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 30 remains, and the pad electrode 30a is electrically connected to the excitation electrode 28 on the opposite surface via the extraction electrode 30. Then, as shown in FIG. 5 (f), the piezoelectric vibrating piece 10 is formed by removing the resist film 48.

  FIG. 6 shows the piezoelectric vibrating piece according to the second embodiment. FIG. 6A is a top view, FIG. 6B is a bottom view, and FIG. 6C is a cross-sectional view taken along line AA in FIG. FIG. 6D is a cross-sectional view taken along the line BB of FIG. The piezoelectric vibrating piece 60 of the second embodiment is basically similar to the first embodiment. That is, as in the first embodiment, the mount portion 62, the buffer portion 64, and the thick portion 70 are formed side by side in the Z ″ axis direction, and the chamfered portion 18 is formed on the mount portion 62. The slit 16 is formed, and the thin portion 71 is formed in the thick portion 70. On the other hand, the vibration part formed in the thin part 71 is formed thick by the mesa part 72 formed on the surface of the thin part 71 on the −Y′-axis side. The excitation electrode 76 may be formed on the mesa portion 72, and the excitation electrode 74 may be different in that the excitation electrode 74 is formed on the surface of the thin portion 71 on the + Y′-axis side and facing the excitation electrode 74. By doing so, the energy of the main vibration that is the thickness shear vibration can be confined in the mesa portion 72. The extraction electrode 26 is connected to the excitation electrode 76 disposed on the surface on the −Y′-axis side of the piezoelectric vibrating piece 60, and the extraction electrode 30 is connected to the excitation electrode 74 disposed on the surface on the + Y′-axis side. Has been. The extraction electrode 26 connected to the excitation electrode 76 passes through the surfaces of the thin portion 71, the thick portion 70, and the connecting portion 15 to the pad electrode 26 a disposed on the surface at the −Y′-axis side of the mount portion 62. Connecting. The extraction electrode 30 connected to the excitation electrode 74 passes through the surfaces of the thin portion 71, the thick portion 70, and the connecting portion 15, and is routed to the −Y′-axis side surface of the piezoelectric vibrating piece 60 by the thick portion 70. Then, it is connected to the pad electrode 30 a disposed on the surface of the mount portion 62 on the −Y′-axis side.

  The manufacturing process of the piezoelectric vibrating piece 60 according to the second embodiment is different in that the mesa portion 72 that is thicker than the thin portion is formed in the center of the thin portion 71 in the half-etching step. This is common with the embodiment. By adopting such a configuration, the vibration region of the thickness shear vibration can be confined to the vibration part (mesa part 72), and the excitation efficiency can be increased.

FIG. 7 shows a modification of the piezoelectric vibrating piece according to the second embodiment. FIG. 7 (a) is a top view, FIG. 7 (b) is a bottom view, and FIG. 7 (c) is A in FIG. -A sectional view, FIG.7 (d) is BB sectional drawing of Fig.7 (a).
As shown in FIG. 7, in the modified example of the second embodiment, it is also preferable to provide the mesa portion 80 on both surfaces of the thin portion 78. At this time, the thin portion 78 is formed by half-etching the shape of the mesa portion 80 from both sides of the quartz substrate 36 (see FIG. 3). Excitation electrodes 74 and 76 are formed on both surfaces of the mesa unit 80. By forming the vibrating portion in this way, the piezoelectric vibrating piece 61 having an enhanced confinement effect of thickness shear vibration can be obtained. In the second embodiment, the excitation electrode 76 is formed in a rectangular shape on the entire surface of the mesa portion 72 with respect to the mesa portion 72, and the excitation electrode 74 is formed in a rectangular shape following the outer shape of the excitation electrode 76. Also. Excitation electrodes 74 and 76 are formed in a rectangular shape on the entire surface of the mesa 80 with respect to the mesa 80. However, for example, a circular shape or an elliptical shape may be used corresponding to the actual vibration region. By doing so, the energy of the main vibration which is the thickness shear vibration can be confined in the mesa part 72 and the mesa part 80, and the CI value of the piezoelectric vibrating pieces 60 and 61 can be increased.

  FIG. 8 shows a piezoelectric vibrating piece according to the third embodiment, where FIG. 8A is a top view and FIG. 8B is a bottom view. FIG. 9 shows a modification of the piezoelectric vibrating piece according to the third embodiment. FIG. 9A is a top view and FIG. 9B is a bottom view. The piezoelectric vibrating reeds 90 and 91 according to the third embodiment are basically similar to the first embodiment, but the longitudinal ends of the slits 100 and 102 formed in the buffer portion 94 in the X′-axis direction are The difference is that the slits 100 and 102 have a shape that is bent or curved so as to be positioned closer to the mount portion 92 than the central portion in the longitudinal direction. As such a shape, like the piezoelectric vibrating piece 90 shown in FIG. 8, the end portion 100a and the end portion 100a in the X′-axis direction of the slit 100 are bent so as to be positioned closer to the mount portion 92 than the central portion 100b. Such a shape is mentioned. Further, like the piezoelectric vibrating piece 91 shown in FIG. 9, there are an arcuate slit 102 that is curved so that the end portion 102 a of the arc and the end portion 102 a are positioned closer to the mount portion 92 than the central portion 102 b of the arc.

  When mounting the piezoelectric vibrating piece by applying the conductive adhesive 32 at two places on the mount portion 92, stress due to thermal distortion occurs on the line connecting the conductive adhesives 32 as described above, and this stress is slit. A component that reaches 100 and 102 and bypasses the periphery of the slits 100 and 102 can be transmitted to the vibrating portion 98 (thin wall portion 96) side. However, by forming the slits 100 and 102 into the above-described shape, the slits 100 and 102 surround the stress generated in the mount portion 92. Therefore, stress leakage to the thin portion 96 side is reduced, and the vibration portion The effect of stress on 98 can be mitigated. This has the same effect regardless of which of FIGS. The third embodiment can be applied to the first embodiment and the second embodiment.

  FIG. 10 shows a piezoelectric vibrating piece according to the fourth embodiment, where FIG. 10A is a top view and FIG. 10B is a bottom view. In the piezoelectric vibrating piece of the fourth embodiment, reinforcing portions 112 formed thinner than the buffer portion 94 are disposed at both ends in the X′-axis direction of the slit 100. In FIG. 10, the case where this embodiment is applied to 3rd Embodiment is shown. In other words, the end portion 100 a of the slit 100 is bent so as to be positioned closer to the mount portion 92 than the central portion 100 b of the slit 100, and the end portion 100 a is closed by the reinforcing portion 112. By forming the slit 100 in the buffer portion 94, the strength of the buffer portion 94 itself may be reduced. However, when the dimension in the X′-axis direction, which is the longitudinal direction of the slit 100, is reduced, the stress generated in the mount portion 92 is easily transmitted to the vibration portion 98 (thin wall portion 96).

  Therefore, by arranging the reinforcing portions 112 as shown in FIG. 10 at both ends (end portion 100a, end portion 100a) of the slit 100 in the X′-axis direction, the propagation of stress to the vibrating portion 98 side of the slit 100 is limited. The strength of the buffer portion 94 can be ensured without impairing the effect. Here, the reinforcing portion 112 can be formed simultaneously with the formation of the thin portion 96. As will be described later, from the viewpoint of stress relaxation also in the thickness direction of the piezoelectric vibrating piece, the reinforcing portion 112 is formed on the mounting surface to which the conductive adhesive 32 of the piezoelectric vibrating piece 110 is applied, like the thin portion 96. It is desirable to dispose it on the opposite surface, that is, the surface on the + Y′-axis side. The reinforcing portion 112 can be disposed at both ends (end portion 102a, end portion 102a) of the slit 102 shown in FIG.

  FIG. 11 shows a piezoelectric vibrating piece according to the fifth embodiment. FIG. 11A is a top view and FIG. 11B is a bottom view. FIG. 12 shows a modification of the piezoelectric vibrating piece according to the fifth embodiment. FIG. 12 (a) is a plan view and FIG. 12 (b) is a bottom view. The piezoelectric vibrating pieces 120 and 121 according to the fifth embodiment are basically similar to the first embodiment, but both ends of the slits 122 and 124 in the longitudinal direction (X′-axis direction) are the lengths of the slits 122 and 124. This is different in that the groove 126 is formed at a position where the slits 122 and 124 of the buffer portion 94 are sandwiched from both ends in the longitudinal direction. To do.

  As such a form, as shown in FIG. 11, the slit 122 of FIG. 8 is symmetrically inverted and the slit 122 is sandwiched from both ends in the X′-axis direction and the end 122a. , 122a, and the piezoelectric vibrating piece 120 having the groove 126 disposed in the vicinity. The end portion 122 a of the slit 122 is bent and disposed so as to be positioned closer to the thin portion 96 than the central portion 122 b of the slit 122. Also, as shown in FIG. 12, the slit 124 having a shape obtained by inverting the slit 102 of FIG. 9 symmetrically and a position sandwiched from both ends in the X′-axis direction of the slit 124 and close to the end portions 124a and 124a. Examples thereof include a piezoelectric vibrating piece 121 having a groove 126 to be disposed. The end portion 124 a of the slit 124 is bent and disposed so as to be positioned closer to the thin portion 96 than the central portion 124 b of the slit 124.

  With the above configuration, the slits 122 and 124 are configured to receive a certain amount of stress generated in the mount portion 92 during mounting to both ends of the slits 122 and 124, but the received stress can be blocked by the groove 126. As a result, the stress generated in the mount portion 92 is made uniform on the mount portion 92 and on the mount portion 92 side of the slits 122 and 124 of the buffer portion 94. Therefore, it is possible to suppress variations in the stress distribution when the piezoelectric vibrating reeds 120 and 121 are mass-produced, thereby suppressing variations in characteristics such as frequency characteristics of the piezoelectric vibrating reeds 120 and 121, thereby reducing costs. Can do.

  Here, the groove 126 can be formed simultaneously with the formation of the thin portion 96. And as will be described later, from the viewpoint of stress relaxation also in the thickness direction of the piezoelectric vibrating piece, like the thin portion 96, the groove 126 is formed on the surface side to which the conductive adhesive 32 of the piezoelectric vibrating pieces 120 and 121 is applied. It is desirable to form by digging from (the surface side on the −Y ′ axis side).

  FIG. 13 shows the strength distribution of stress when stress 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 has almost the same form as that of the first embodiment (see FIG. 1). Then, as shown in FIG. 13, the piezoelectric force is applied when a force attracting each other or a force pushing each other is applied between the two points at the center of the two circles drawn on the mounting surface of the mount portion. The stress distribution of the vibrating piece was simulated.

  The pattern arranged in a vertical line on the left side of FIG. 13 shows the strength (level 1 to level 9) of the stress received by each type of piezoelectric vibrating piece due to the stress generated in the mount portion. Here, level 9 indicates a region that receives the greatest stress, the stress that is received decreases from level 9 to level 1, and level 1 indicates a region that receives the minimum stress or is below the detection limit of stress. These patterns are drawn corresponding to the intensity distribution of stress received by the piezoelectric vibrating piece on each type of piezoelectric vibrating piece. Hereinafter, the simulation results in FIG. 13 will be described in correspondence with the components of the piezoelectric vibrating piece 10 shown in FIG.

  As shown in FIG. 13, 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 generated in the mount portion 12 propagates to the mount portion 12 side of the slit 16, but the stress received at both ends of the slit 16 on the X′-axis side is level 9 or less. This is because the chamfered portion 18 formed in the mount portion 12 shortens the length of the mount portion 12 in the X′-axis direction, thereby reducing the distance between the conductive adhesives 32 and the stress itself generated in the mount portion 12. This is thought to be due to the small size.

  In the connecting portion 15, the stress received is level 9 again. This is considered that the stress that propagates linearly between the conductive adhesive 32 and the connecting portion 15 and the stress that propagates through the periphery of the slit 16 on the mount portion 12 side merge.

  The stress reaching the connecting portion 15 propagates to the thick portion 17 in a form that propagates around the slit 16, but is relaxed to about level 7 and level 6 while propagating around the slit 16. Thereby, since the path of the stress generated in the mount portion 12 is bent by the slit 16, the straight path that propagates the strongest in the stress is blocked, and as a result, the stress is relieved at a large rate during the propagation. I understand.

  In the thick portion 17 adjacent to the slit 16, the region receiving the level 6 stress is dominant on the slit 16 side, but the region receiving the level 7 stress is dominant on the thin portion 21 side. This is because the angle at which the stress path from the connecting portion 15 to the slit 16 side of the thick portion 17 is bent is larger than the angle at which the stress path from the connecting portion 15 to the thin portion 16 side of the thick portion 17 is bent. It is considered that stress relaxation is promoted as the angle at which the path is bent increases. Therefore, it is considered that in the thick portion 17, the level of stress received on the thin portion 21 side is higher than that on the slit 16 side.

  The stress received at the thick portion 17 side of the boundary between the thick portion 17 and the thin portion 21 is level 7, but at the thin portion 21 side, the stress is level 3. Has occurred. Here, a step is formed between the thin portion 21 and the thick portion 17 on the surface (mounting surface) on the −Y′-axis side to which the above-described stress of the piezoelectric vibrating piece 10 is applied. Therefore, the stress remaining in the thin portion 21 is a succession of the stress on the surface at the −Y′-axis side of the thick portion 17. From this, the stress is relaxed also in the thickness direction of the piezoelectric vibrating piece 10 from the applied −Y′-axis side surface (mounting surface) to the + Y-axis side surface, and the thick portion 17 and the thin portion 21 It is thought that there was a step in the stress level at the boundary.

  In the central portion of the thin-walled portion 21, the stress received is level 2 and level 1, and this region is used as the vibration portion 22 (forms an excitation electrode), so that the stress is hardly affected. Therefore, a piezoelectric vibrating piece having good frequency characteristics can be constructed.

  FIG. 14 shows a piezoelectric vibrator on which the piezoelectric vibrating piece of this embodiment is mounted. FIG. 14A is a top view of the piezoelectric vibrator when the piezoelectric vibrating piece 60 shown in FIG. 6 is mounted, and FIG. 14B is a cross-sectional view taken along the line AA in FIG. The piezoelectric vibrator 200 is formed by a package 202 (substrate) having a recess 204 that houses the piezoelectric vibrating piece 60 and a lid 212 that seals the recess 204. An external electrode 206 is formed on the lower surface of the package 202, and a connection electrode 210 electrically connected to the external electrode 206 through the through electrode 208 is disposed on the bottom surface of the recess 204. Then, the connection electrode 210 and the pad electrodes 26 a and 30 a arranged on the mount portion 62 are joined by the conductive adhesive 32. Therefore, the piezoelectric vibrating piece 60 is connected to the package 202 in a cantilevered state with the mount portion 62 as a fixed end. Further, the external electrode 206 and the extraction electrodes 26 and 30 are electrically connected. With the above configuration, the piezoelectric vibrator 200 in which the stress on the vibrating portion (mesa portion 72) of the piezoelectric vibrating piece 60 is relaxed is obtained.

  15 and 16 show an electronic device on which the piezoelectric vibrating piece according to this embodiment is mounted. FIG. 15 is an exploded perspective view of an electronic device on which the piezoelectric vibrating piece 10 shown in FIG. 1 is mounted. 16A is a cross-sectional view taken along line AA when the piezoelectric vibrating piece 60 shown in FIG. 6 is mounted in FIG. 15, and FIG. 16B is a piezoelectric vibrating piece 61 shown in FIG. It is an AA line sectional view at the time of carrying.

The electronic device 300 according to this embodiment includes a package 302 (substrate), an integrated circuit (IC 310) that drives the piezoelectric vibrating reeds 10, 60, and 61, and a lid 312.
The package 302 is formed in a three-layer structure as indicated by a broken line in FIG. An external electrode 314 is formed on the lower surface of the package 302. A plurality of connection electrodes 316 are arranged in the lower step 306 of the recess 304 of the package 302. A plurality of connection electrodes 316 are formed so as to face the plurality of pad electrodes 320 formed on the IC 310, and each connection electrode 316 is connected to the corresponding pad electrode 320 by an adhesive 322. In addition, a connection electrode 318 that is connected to the pad electrodes 26 a and 30 a of the piezoelectric vibrating reeds 10, 60 and 61 via the conductive adhesive 32 is formed on the upper step 308 of the recess 304 of the package 302.

  As described above, the connection electrode 316 formed in the lower step 306 of the recess 304 of the package 302 is connected to the pad electrode 320, but the connection electrode 318 is electrically connected to the external electrode 314. There is something to connect. Therefore, the IC 310 is electrically connected to the outside via the connection electrode 316 and the external electrode 314, and the pad electrodes 26 a and 30 a of the piezoelectric vibrating reeds 10, 60, and 61 are electrically connected to the IC 310 via the connection electrode 318 and the connection electrode 316. Connected to. Therefore, the IC 310 can drive the piezoelectric vibrating reeds 10, 60, 61 when electric power is supplied via the external electrode 314. The electronic device 300 according to the present embodiment has a structure in which the piezoelectric vibrating reeds 10, 60, 61 and the IC 310 are sealed with a single seal by a lid 312 in the recess 304. With the above configuration, the electronic device 300 in which the stress on the vibration part of the piezoelectric vibrating reeds 10, 60, 61 is relaxed is obtained.

  FIG. 17 shows a first modification of the electronic device of this embodiment. In FIG. 17, concave portions 404 and 406 are formed on both surfaces of a package 402 (substrate), and a piezoelectric vibrating piece 60 (which may be the piezoelectric vibrating piece 10 or the like) is mounted on one concave portion 404 and sealed with a lid 408. The other concave portion 406 is an electronic device 400 having a structure in which an integrated circuit (IC416) is attached. An external electrode 410 is formed at the lower end of the package 402, and the recess 406 is electrically connected to the connection electrode 420 disposed in the external electrode 410 or the recess 404, and the pad electrode 418 of the IC 416 through the wire 414. A connection electrode 412 that is electrically connected to is disposed.

  On the other hand, the connection electrode 420 disposed in the recess 404 is connected to the pad electrodes 26 a and 30 a of the piezoelectric vibrating piece 60 through the conductive adhesive 32. Therefore, the piezoelectric vibrating piece 60 is connected to the package 402 in a cantilevered state with the mount portion 62 as a fixed end. By isolating the piezoelectric vibrating piece 60 and the IC 416 in this way, the influence of heat from the IC 416 of the piezoelectric vibrating piece 60 can be reduced.

  FIG. 18 shows a second modification of the electronic device of this embodiment. FIG. 18A is a side view, and FIG. 18B is a top view of a substrate constituting the electronic device. In the second modification, for example, the electronic device 500 is formed using a piezoelectric vibrator 200 shown in FIG. That is, in the second embodiment, an electrode sphere 512 that is electrically connected to the IC 504 (pad electrode 506) is disposed on a substrate 502 on which an integrated circuit (IC 504) that drives the piezoelectric vibrator 200 is mounted. The piezoelectric vibrator 200 is supported by 512, and the electrode sphere 512 and the external electrode 206 of the piezoelectric vibrator 200 are electrically connected, and the substrate 502, the IC 504, the electrode sphere 512, and the piezoelectric vibrator 200 are made of a molding agent such as a resin. 516 is integrally formed. Here, an external electrode 510 is formed on the lower surface of the substrate 502, and a connection electrode 508 that is electrically connected to the external electrode 510 via the through electrode 518 is formed on the upper surface of the substrate 502. A part of the pad electrode 506 formed on the IC 504 is connected to the electrode sphere 512 via the wire 514, and the rest is connected to the connection electrode 508 via the wire 514.

  With the above-described configuration, the electronic device 500 can be formed by arranging the substrate 502, the IC 504, the electrode sphere 512, and the like corresponding to the standard of the existing piezoelectric vibrator 200, so that the cost can be suppressed. . In any of the embodiments, the connection between the IC and each electrode may use a face-down bonding method. In any embodiment of the piezoelectric vibrator and electronic device, the piezoelectric vibrating piece of any of the above-described embodiments can be applied.

  In the above-described electronic device, the piezoelectric vibrator is described as having a configuration including an electronic component typified by a semiconductor element (IC). However, it is preferable to include at least one electronic component. As the electronic component, a thermistor, a capacitor, a reactance element or the like can be applied, and an electronic device using a piezoelectric vibrating piece as an oscillation source can be constructed. Further, when the long side of the piezoelectric vibrating piece is in the Z ″ axis direction, the conductive adhesive is such that the direction of the line connecting the two application positions (connecting portions) of the conductive adhesive 32 is in the X ′ axis direction. 32 is applied (see FIG. 1). As a result, it is possible to construct an electronic device (piezoelectric vibrator) in which the component propagating to the vibration part side of the stress generated in the mount part 12 is reduced and the influence of the stress on the vibration part is reduced. When the long side of the piezoelectric vibrating piece is in the X′-axis direction, the conductive bonding is performed so that the direction of the line connecting the two application positions (connecting portions) of the conductive adhesive 32 becomes the Z′-axis direction. Agent 32 is applied. Thereby, the stress itself generated in the mount part 12 can be reduced, and an electronic device (piezoelectric vibrator) in which the influence of the stress on the vibration part is reduced can be constructed.

10 ......... Piezoelectric vibrator element, 10a ......... Piezoelectric element board, 11 ......... Piezoelectric element board, 11a ......... AT-cut quartz substrate, 12 ......... Mount part, 14 ......... Buffer part, 16 ... ... Slit, 17 ......... Thick part, 18 ......... Chamfered part, 21 ......... Thin part, 21a ......... Concave part, 22 ......... Vibrating part, 24 ...... Excitation electrode, 26 ...... Drawer Electrode, 26a ... Pad electrode, 28 ... Excitation electrode, 30 ... Extraction electrode, 30a ... Pad electrode, 32 ... Conductive adhesive (connection part), 34 ... Substrate, 36 ......... Quartz substrate, 38 ......... Resist film, 38a ......... Resist film, 40 ...... Photomask, 42 ......... Resist film, 42a ......... Resist film, 44 ...... Photomask, 46 ... ... Metal film, 48 ... Resist film, 48a ... Resist film, 50 ... Photo , 60 ......... piezoelectric vibrating piece, 61 ......... piezoelectric vibrating piece, 62 ......... mounting part, 64 ......... buffering part, 70 ......... thick part, 71 ......... thin part, 72 ... ... mesa portion, 74 ... excitation electrode, 76 ... excitation electrode, 78 ... thin wall portion, 80 ... mesa portion, 90 ... piezoelectric vibration piece, 91 ... piezoelectric vibration piece, 92 ... ...... Mount part, 94 ......... Buffer part, 96 ......... Thin part, 98 ......... Vibration part, 100 ......... Slit, 100a ......... End part, 100b ......... Center part, 102 ......... Slit, 102a ......... End, 102b ......... Center, 110 ......... Piezoelectric vibrating piece, 112 ......... Reinforcing part, 120 ......... Piezoelectric vibrating piece, 121 ......... Piezoelectric vibrating piece, 122 ... ... Slit, 122a ......... End, 122b ......... Center, 124 ......... Slit, 124a ......... End 124b ......... Center portion, 126 ......... Groove, 200 ......... Piezoelectric vibrator, 202 ......... Package, 204 ......... Recess, 206 ......... External electrode, 208 ......... Penetration electrode, 210 ... ...... Connecting electrode, 212... Lid, 214... Extraction electrode, 215... Extraction electrode, 300... Electronic device, 302... Package, 304. 308... Upper stage, 310... IC, 312... Lid, 314... External electrode, 316 ... Connection electrode, 318 ... Connection electrode, 320 ... Pad electrode, 322 ... adhesive, 400 ...... electronic device, 402 ......... package, 404 ......... concave, 406 ......... concave, 408 ......... lid, 410 ...... external electrode, 412 ...... connection electrode, 414 .... Wire, 41 6 ... IC, 418 ... Pad electrode, 420 ... Connection electrode, 500 ... Electronic device, 502 ... Substrate, 504 ... IC, 506 ... Pad electrode, 508 ...... Connection electrode, 510... External electrode, 512... Electrode ball, 514... Wire, 516... Molding agent, 518. , 604... Vibration part, 606 A ... Excitation electrode part, 606 B ... Excitation electrode part, 608 A ... Input / output terminal part, 608 B ... Input / output terminal part, 610 ... ... Slit, 612 ……… Container, 614 ……… Bottom, 616 ……… Adhesive.

Claims (13)

A crystal axis of quartz, an X-axis as an electric axis, a Y-axis as a mechanical axis, and a Z-axis as an optical axis, the X-axis of a Cartesian coordinate system as a rotation axis, and the Z-axis as the rotation axis An axis rotated in the −Y direction of the Y axis is a Z ′ axis, an axis rotated in the + Z direction of the Z axis is a Y ′ axis, and a plane parallel to the X axis and the Z ′ axis Formed by an AT-cut crystal having a thickness parallel to the Y′-axis and having a vibrating portion, and a thick portion provided on the periphery of the thin portion and thicker than the thin portion. A piezoelectric vibrating piece provided,
The piezoelectric vibrating piece is
Z obtained by rotating the + Z ′ axis around the Y ′ axis in the + X axis direction as a positive rotation angle and rotating the Z ′ axis around the Y ′ axis in a range of −120 ° to + 60 °. Each having an edge parallel to the ″ axis and the X ′ axis obtained by rotating the X axis around the Y ′ axis together with the Z ′ axis,
The thick part is connected side by side with a mount part through a buffer part in the direction of the edge,
The buffer part has a slit between the mount part and the thick part,
The mount part is
A chamfered portion is provided at both ends in a direction orthogonal to the direction in which the mount portion, the buffer portion, and the thick portion are aligned,
The piezoelectric vibrating piece according to claim 1, wherein at least part of the longitudinal direction of the slit is parallel to the orthogonal direction.   2. The piezoelectric vibrating piece according to claim 1, wherein a direction in which the thick portion, the buffer portion, and the mount portion are arranged is a direction of an edge parallel to the Z ″ axis.   2. The piezoelectric vibrating piece according to claim 1, wherein a direction in which the thick portion, the buffer portion, and the mount portion are arranged is a direction of an edge parallel to the X ′ axis.   4. The device according to claim 1, wherein both end portions of the slit in the longitudinal direction are bent or curved so as to be positioned closer to the mount portion than the center portion in the longitudinal direction of the slit. The piezoelectric vibrating piece according to Item.   5. The piezoelectric vibrating piece according to claim 1, wherein a reinforcing portion formed in a thin wall is disposed at each of the both ends of the slit. The slit has a shape that is bent or curved so that both ends of the slit in the longitudinal direction are located on the side of the thin portion with respect to the center in the longitudinal direction of the slit,
4. The piezoelectric vibrating piece according to claim 1, wherein a groove is formed at a position where the slit of the buffer portion is sandwiched from both ends in the longitudinal direction. Excitation electrodes for vibrating the vibrating portion are formed on both surfaces of the vibrating portion,
On the mounting surface of the mount portion, a pair of lead electrodes electrically connected to each excitation electrode is formed,
The piezoelectric vibrating piece according to claim 1, wherein the thin-walled portion is connected to the thick-walled portion while being biased toward the opposite surface of the mounting surface.   The piezoelectric vibrating piece according to claim 1, wherein the vibrating portion is formed thicker than the thin-walled portion. Having a substrate,
The mounting surface of the mounting portion of the piezoelectric vibrating piece according to any one of claims 1 to 8 is directed toward the substrate side, and the pair of connection portions of the mount portion and the substrate facing the pair of connection portions A piezoelectric vibrator, wherein the piezoelectric vibrating piece is mounted by bonding a pair of parts using a bonding member.   10. The piezoelectric vibrator according to claim 9, wherein a direction connecting the pair of connection portions is parallel to the X ′ axis or the Z ″ axis. Having a substrate,
The mounting surface of the mounting portion of the piezoelectric vibrating piece according to any one of claims 1 to 8 is directed to the substrate side, the pair of connecting portions of the mounting portion, and the substrate facing the pair of connecting portions. An electronic device comprising: the piezoelectric vibrating piece mounted by bonding with a pair of parts and a bonding member, and comprising at least one electronic component.   The electronic device according to claim 11, wherein a direction connecting the pair of connection portions is parallel to the X ′ axis or the Z ″ axis.   13. The electronic device according to claim 11, wherein the electronic component is any one of a thermistor, a capacitor, a reactance element, and a semiconductor element.

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