JP2012156592A - Piezoelectric vibration piece, piezoelectric vibrator and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric vibration piece which has had its stress to a vibration part when mounted on-board relieved and a piezoelectric vibrator and an electronic device using the vibration piece.SOLUTION: A piezoelectric vibration piece 10 comprises a thin part 21 having a vibration part 22 and a thick part 17 provided on a periphery of the thin part 21 and greater in thickness than the thin part 21. The thick part 17 has a mount part 12 connected in a row thereto via a buffer part 14, characterized in that the buffer part 14 has a slit 16 between the mount part 12 and the thick part 17, the mount part 12 has notched parts 18 at both ends thereof in an orthogonal direction to a direction in which the mount part 12, the buffer part 14 and the thick part 17 are arranged in a row, at least part in a longitudinal direction of the slit 16 being parallel to the orthogonal direction, the width in the orthogonal direction of the mount part 12 being narrower than the width in the longitudinal direction of the slit part 16, and both ends in the longitudinal direction of the slit part 16 being located closer to an outer periphery of the buffer part 14 in the orthogonal direction than are both ends of the mount part 12.

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.

  Further, when attempting to reduce the size of the piezoelectric vibration element piece, the resonance frequency of the piezoelectric vibration element piece may change over time due to the residual stress generated by the curing of the adhesive applied to the support portion of the piezoelectric vibration element piece, or There is a problem in that the area of the excitation electrode has to be reduced, which causes a problem that the electrical characteristics of the piezoelectric vibration element deteriorate. 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. 20 is a schematic diagram of a piezoelectric vibrator according to Patent Document 12. 20A is a top view of the piezoelectric vibrating piece constituting the piezoelectric vibrator, FIG. 20B is a bottom view of the piezoelectric vibrating piece constituting the piezoelectric vibrator, and FIG. FIG. 20D is a cross-sectional view taken along the line AA ′ of FIG. 20C.

  In FIG. 20, 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 indicated by the two-dot chain line in FIG. 20C, residual stress is generated on the piezoelectric vibrator 600. 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).

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

  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. 21 shows a stress distribution when a slit is formed between the mount portion and the vibration portion of the piezoelectric vibrating piece. FIG. 21A shows a case where the width of the slit of the piezoelectric vibrating piece in the Z′-axis direction is 150 μm. FIG. 21B shows the stress distribution when the width in the Z′-axis direction of the slit of the piezoelectric vibrating piece is 250 μm. 22 and FIG. 23, a connecting portion for connecting the mount portion and the vibration portion by forming a notch at a position between the mount portion and the vibration portion on both sides in the width direction of the piezoelectric vibration piece. 22 (a) shows the stress distribution when the width of the connecting portion in the X-axis direction is 400 μm, and FIG. 22 (b) shows the width of the connecting portion in the X-axis direction as 300 μm. FIG. 23A shows the stress distribution when the width of the connecting portion in the X-axis direction is 200 μm, and FIG. 23B shows the stress when the width of the connecting portion in the X-axis direction is 100 μm. Show the distribution.

  21, 22, and 23 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.

  21, 22, and 23, 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 that is normal to 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. 21, 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 portion 702 side to the end of the mount portion 702 is 350 μm in FIG. 21A and 250 μm in FIG. The width of the slit 704 in the Z′-axis direction is 150 μm in FIG. 21A and 250 μm in FIG. That is, in FIG. 21A and FIG. 21B, the position and width of the slit 704 in the Z′-axis direction are changed.

  21, 22, and 23, 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. 21, 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 FIGS. 22 and 23 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 piezoelectric vibrating piece including a thin part having a vibration part and a thick part provided at a periphery of the thin part and thicker than the thin part. Mount portions are connected side by side through the portion, the buffer portion has a slit between the mount portion and the thick portion, and the mount portion includes the mount portion, the buffer portion, and the thick wall portion. The slits have notches at both ends in the direction orthogonal to the direction in which they are aligned, the longitudinal direction of the slit is parallel to the orthogonal direction, and the width of the mount part in the orthogonal direction is set to the length of the slit. The piezoelectric vibrating piece according to claim 1, wherein both ends of the slit in the longitudinal direction are closer to the outer periphery in the orthogonal direction of the buffer portion than the both ends of the mount portion.

  In the above configuration, the mounting portion is coated with two conductive adhesives arranged in the orthogonal direction. Therefore, in the piezoelectric vibrating piece, stress due to thermal strain is generated on the line connecting the conductive adhesives and propagates to the vibrating portion side. However, by interposing the slit at a position in the middle of the propagation, the straight path that propagates the strongest in the stress is cut off, and only the stress component that bypasses the slit can propagate to the vibrating portion side. And since the width | variety of a mount part becomes narrower than the length of the longitudinal direction of a slit like the said structure, the component of the stress which bypasses a slit can be reduced significantly. Therefore, the piezoelectric vibrating piece is reduced in the influence of stress on the vibrating portion.

[Application Example 2] In Application Example 1, wherein both ends of the slit in the longitudinal direction are bent or curved so as to be positioned closer to the mount part than the center part in the longitudinal direction of the slit. The piezoelectric vibrating piece according to the description.
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 3 Application Example 1 or 2 in which the slit is provided with a reinforcing portion that is thinner than the buffer portion and extends from the both end portions of the slit toward the central portion of the slit. The piezoelectric vibrating piece according to 1.
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 4 The slit has a shape that is bent or curved so that both end portions in the longitudinal direction of the slit are positioned on the thin-walled portion side with respect to the center portion in the longitudinal direction of the slit. The piezoelectric vibrating piece according to Application Example 1, wherein a groove extending from the both end portions toward the notch is formed between the notch and the notch.

  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 5 With respect to the X axis of an orthogonal coordinate system including 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 is parallel to the X axis and the Z 'axis. 5. The piezoelectric vibrating piece according to any one of Application Examples 1 to 4, wherein the piezoelectric vibrating piece is made of an AT-cut quartz crystal 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 6 Excitation electrodes are arranged on both main surfaces of the vibration part, and a pair of extraction electrodes each electrically connected to the excitation electrode are arranged on the mounting surface of the mount part. The piezoelectric vibrating piece according to any one of Application Examples 1 to 5, wherein the portion is connected to the thick-walled portion while being biased toward the main surface opposite to 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 7 The piezoelectric vibrating piece according to any one of Application Examples 1 to 6, wherein the vibrating portion is thicker than the thin portion.
With the above configuration, the thickness shear vibration can be confined to the vibration part, and the excitation efficiency can be increased.

Application Example 8 Having a substrate, the mounting surface of the mounting portion of the piezoelectric vibrating piece according to any one of Application Examples 1 to 7 is directed to the substrate side, and the mount portion and the substrate are conductively bonded. A piezoelectric vibrator comprising the piezoelectric vibrating piece mounted by bonding with an agent.
With the above configuration, a piezoelectric vibrator in which stress on the vibration part is relaxed is obtained.

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 7 is directed to the substrate side, and the mount portion and the substrate are conductively bonded. An electronic device comprising: the piezoelectric vibrating piece mounted by bonding with an agent; and at least one electronic component.
With the above configuration, an electronic device in which stress on the vibration part is relaxed is obtained.

Application Example 10 In the electronic device according to Application Example 9, 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.

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 rear view, and FIG. 2C is a cross-sectional view taken along line AA in FIG. FIG. 2 and FIG. 2D are cross-sectional views taken along the line BB of FIG. 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. 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 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 plan 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 plan 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 plan view, and FIG. 11B is a bottom view. FIG. 12A is a schematic diagram of a modification of the piezoelectric vibrating piece according to the fifth embodiment, FIG. 12A is a plan view, and FIG. 12B is a bottom view. It is a figure which shows intensity distribution of the stress at the time of applying a stress to the mount part of the piezoelectric vibrating piece (type 1) of this 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 (type 2) of this embodiment. FIG. 15A is a schematic diagram of a piezoelectric vibrator on which the piezoelectric vibrating piece according to the present embodiment is mounted, FIG. 15A is a plan 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.15 (a). It is a disassembled perspective view of the electronic device carrying the piezoelectric vibrating piece shown in FIG. FIG. 17A is a schematic diagram of an electronic device equipped with the piezoelectric vibrating piece according to the present embodiment, and FIG. 17A is a cross-sectional view taken along line AA in FIG. 16 when the piezoelectric vibrating piece shown in FIG. 17B is a cross-sectional view taken along line AA in FIG. 16 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. The schematic diagram of the 2nd modification of the electronic device of this embodiment is shown, Fig.14 (a) is a side view, FIG.14 (b) is a top view of the board | substrate which comprises an electronic device. FIG. 20A is a schematic diagram of a piezoelectric vibrating element according to Patent Document 12, and FIG. 20A is a top view of a piezoelectric vibrating piece constituting the piezoelectric vibrator, and FIG. 20B is a lower surface of the piezoelectric vibrating piece constituting the piezoelectric vibrator. FIG. 20C is a plan view of a piezoelectric vibrator having a piezoelectric vibrating piece mounted inside the container, and FIG. 20D is a cross-sectional view taken along line AA ′ of FIG. FIG. 21A shows the stress distribution when a slit is formed between the mount portion and the vibrating portion of the piezoelectric vibrating piece. FIG. 21A 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. 22A shows the stress distribution when the width of the connecting portion is 400 μm, and FIG. 22B 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. 23A shows the stress distribution when the width of the connecting portion is 200 μm, and FIG. 23B 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. 1A and 1B are schematic views of the piezoelectric vibrating piece according to the first embodiment. FIG. 1A is a plan view, FIG. 1B is a bottom view, and FIG. 1C shows a cut angle of a quartz substrate. FIG. 2A and 2B are schematic views of the piezoelectric vibrating piece according to the first embodiment. FIG. 2A is a front view, FIG. 2B is a rear view, and FIG. 2C is A in FIG. -A sectional view, FIG.2 (d) is BB sectional drawing of Fig.1 (a).

  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, An axis obtained by tilting the Z axis in the −Y direction of the Y axis (about 35 ° 15 ′) around the X axis of the orthogonal coordinate system comprising the Z axis as an optical axis is defined as the Z ′ axis, and An axis obtained by inclining the Y axis in the + Z direction (about 35 ° 15 ′) of the Z axis is defined as a Y ′ axis, and is configured by a plane parallel to the X axis and the Z ′ axis. Uses an AT-cut quartz with a thickness of. As a result, the piezoelectric vibrating piece 10 capable of efficiently oscillating thickness shear vibration is obtained.

  Then, the above-described AT-cut quartz base plate is used to form the piezoelectric vibrating piece 10 having a rectangular outer shape with the short side direction as the X-axis direction and the long side direction as the Z′-axis direction. The piezoelectric vibrating piece 10 has an inverted mesa type 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. It has a structure having a vibrating portion 22. In addition, 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 in 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 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 whose longitudinal direction is the X-axis direction. Thereby, the connection part 15 which connects the thick part 17 and the mount part 12 is formed in the both ends of the buffer part 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. And as shown in FIG.1 (b), the above-mentioned extraction electrodes 26 and 30 are formed also in the buffer part 14 (connection part 15).

  The mount portion 12 is disposed at an end portion on the −Z′-axis side of the piezoelectric vibrating piece 10, and notches 18 are formed at both ends in the X-axis direction. The notch 18 includes two corners included in the mount 12 in plan view among the four corners of the piezoelectric vibrating piece 10 having a rectangular shape, and is parallel to the X-axis direction. The two corners are respectively cut using a trajectory plane formed by translating a rectangular (or L-shaped) outline having a side parallel to the side and the Z′-axis in the Y′-axis direction. Formed in a manner. At this time, the width of the corner portion of the mount portion 12 cut in the X-axis direction is larger than the width of the connecting portion 15 in the buffer portion 14 in the X-axis direction. Therefore, as shown in FIG. 1B, the width C of the mount portion 12 in the X-axis direction is narrower than the width D of the slit 16 in the X-axis direction. Further, the mount portion 12 is arranged such that the slit 16 protrudes from both ends of the mount portion 12 in the X-axis direction when viewed from the direction in which the mount portion 12, the buffer portion, and the thick portion 17 are arranged, that is, the Z′-axis direction. It will be.

  On one main surface (the surface on the −Y′-axis side) of the mount portion 12 serving as a mounting surface, extraction electrodes 26 and 30 that are electrically connected to excitation electrodes 24 and 28 described later are disposed. A conductive adhesive 32 for adhering to the mounting-side substrate 34 is applied to the extraction electrodes 26 and 30. Therefore, a piezoelectric vibrator is formed by bonding to the substrate 34 using the conductive adhesive 32.

  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 connected to the end surface of the piezoelectric vibrating piece 10 from the −Y′-axis side. The lead electrode 26 is electrically connected to the lead electrode 26 drawn to the + Y′-axis side. Therefore, by applying an AC voltage to the extraction electrodes 26 and 30, the vibration part 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 is lowered after the adhesive is cured, the heat of the piezoelectric vibrating piece 10, the 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. Thermal distortion due to the difference in expansion coefficient occurs, and the stress due to this propagates to the entire piezoelectric vibrating piece 10.

  However, due to the notch portion 18 formed in the mount portion 12, the mount portion 12 is narrower in the X-axis direction in the −Z′-axis direction than the buffer portion 14. 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. Further, the stress generated between the mount portion 12 and the conductive adhesive 32 has the largest stress component that travels straight toward the vibrating portion 22 side (component that travels in the + Z′-axis direction). 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, the stress can be relieved at a large rate because the stress traveling path (propagation path) is bent each time the stress travels toward the vibrating portion 22 side. As described above, the width of the mount portion 12 in the X-axis direction is made narrower than the width of the slit 16 in the X-axis direction, thereby bypassing the slit 12 as described with reference to FIGS. The stress component to be reduced can be greatly reduced. 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 distortion generated in the mount portion 12 can be alleviated in the slit 16, thereby suppressing the frequency fluctuation and increasing the yield of the piezoelectric vibrator using the piezoelectric vibrating piece 10. it can.

  Furthermore, the vibration part 22 is formed thinner than the buffer part 14. As a result, the stress that the vibration part 22 receives from the buffer part 14 is attenuated as described above, and the side wall on the vibration part 22 side of the thick part 17 located between the vibration part 22 and the buffer part 14 is further attenuated. Therefore, the stress on the vibration part 22 can be suppressed very effectively. In other words, as shown in FIG. 1, the thin portion 21 (vibrating portion 22) is connected to the thick portion 17 at the surface from which the extraction electrodes 26 and 30 of the piezoelectric vibrating piece 10 are drawn (on the −Y′-axis side). The surface is unevenly distributed on the surface opposite to the surface (the surface on the + Y′-axis side), and a step is formed on the −Y′-axis side with the thick portion 17. Therefore, since the distance from the conductive adhesive 32 applied to the extraction electrodes 26 and 30 is increased by the above-described step, the stress reaching the vibration part 22 can be more relaxed.

Next, the manufacturing process of the piezoelectric vibrating piece according to 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 and extraction electrodes 26 and 30 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. 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 photosensitive as shown in FIG. 4C. The resist film 42a thus removed 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. As a result, the piezoelectric element plate 10a having the outer shape of the piezoelectric vibrating piece 10 (including the slit 16 and the notch 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 10b 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 10b 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 and the extraction electrodes 26 and 30 on both surfaces of the piezoelectric vibrating piece 10. At this time, the resist film 48 in a portion (not shown) passing through the end face 10b 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 passing through the end face of the extraction electrode 30 remains, and the extraction electrode 30 is electrically connected to the excitation electrode 28 on the opposite surface. 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 of 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. 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 in this order along the Z′-axis direction, and the notch portion 18 is formed in 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 at the −Y′-axis side of the thin part 71. 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 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 piezoelectric vibrating piece 61 according to the modification of the second embodiment, the mesa portion 80 is provided on both surfaces of the thin portion 78. At this time, in the region where the thin portion 78 is formed, the thin portion 78 and the mesa portion 80 are half-etched from both sides until the thickness of the mesa portion 80 is reached, and the region of the thin portion 78 leaving the region of the mesa portion 80. Is formed by a half-etching process from both sides until the thickness of the thin portion 78 is reached. 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. FIG. 8A is a plan 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 plan view and FIG. 9B is a bottom view. The piezoelectric vibrating reeds 90 and 91 according to the third embodiment are basically similar to those of the first embodiment, but both ends of the slits 100 and 102 formed in the buffer portion 94 in the longitudinal direction in the X-axis direction are slits. 100 and 102 differ in that they have a bent or curved shape so as to be positioned closer to the mount portion 92 than the central portion in the longitudinal direction.

  Examples of such a shape include a slit 100 formed in the piezoelectric vibrating piece 90 shown in FIG. 8 and a slit 102 formed in the piezoelectric vibrating piece 91 shown in FIG. In FIG. 8, the slit 100 has a central portion 100b extending in the X-axis direction, and a bent portion 100c connected to both ends of the central portion 100b in the X-axis direction and having a longitudinal direction on the mount portion 92 side. The end of the mounting portion 12 side (notch portion 18 side) is an end portion 100 a of the slit 100. Therefore, the slit 100 as a whole has a shape in which both ends in the X-axis direction are bent toward the mount portion 92 side (notch portion 18 side), and the end portion 100a of the slit 100 is closer to the mount portion 12 side than the central portion 100b of the slit 100. It arrange | positions at the (notch part 18 side).

  In FIG. 9, the slit 102 has an arcuate shape that is curved so that the end portion 102a and the end portion 102a face the mount portion 92 side (notch portion 18 side). Therefore, the end portion 102 a of the slit 102 is disposed on the mount portion 12 side (notch portion 18 side) from the central portion 102 b of the slit 102.

  Therefore, the slit 100 and the slit 102 have a portion extending in the direction perpendicular to the Z′-axis direction (that is, the X-axis direction) at the center in the longitudinal direction. Each of the slits described above can be obtained by opening through holes in the piezoelectric vibrating pieces 90 and 91 following the outer shape of each slit. 8A, the normal line 100d of the side surface forming the end portion 100a out of the side surface of the through hole forming the slit 100 (end surface of the piezoelectric vibrating piece 90) is on the Z ′ axis and the X axis. It faces the direction that intersects at an acute angle. As shown in FIG. 9A, the normal line 102c of the side surface forming the end portion 102a out of the side surface of the through hole forming the slit 102 (end surface of the piezoelectric vibrating piece 91) is on the Z ′ axis and the X axis. It faces the direction that intersects at an acute angle.

  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. There is a possibility that a component that reaches 100 and 102 and bypasses the periphery of the slits 100 and 102 may 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. FIG. 10A is a plan view and FIG. 10B is a bottom view. In the slit 100 of the piezoelectric vibrating piece according to the fourth embodiment, the reinforcing portion 112 is formed thinner than the buffer portion and extends from both end portions (end portion 100a, end portion 100a) of the slit 100 toward the central portion 100b of the slit 100. Is arranged. FIG. 10 shows a case where the present embodiment is applied to the third embodiment, and a part or all of the bent portions 100c, 100c are closed by the reinforcing portion 112 with the end portions 100a, 100a at both ends of the slit 100 as base points. It becomes the shape that was made. 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 portion 96).

  Therefore, by arranging the reinforcing portions 112 as shown in FIG. 10 on both ends of the slit 100, the strength of the buffer portion 94 is increased without impairing the effect of restricting the propagation of stress to the vibrating portion 98 side of the slit 100. Can be secured. 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. 11 (a) is a plan view, and FIG. 11 (b) 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 reeds 120 and 121 according to the fifth embodiment are basically similar to the first embodiment, but the longitudinal ends of the slits 122 and 124 are more than the central portions of the slits 122 and 124 in the longitudinal direction. The difference is that the thin portion 96 has a bent or curved shape. Further, the difference is that a groove 126 extending from the vicinity of both end portions toward the notch portion 18 is formed between the both end portions and the notch portion 18.

  As shown in FIG. 11, the slit 122 formed in the piezoelectric vibrating piece 120 has a shape in which the slit 100 is symmetrically inverted about a line parallel to the X axis. That is, the slit 122 has a central portion 122b extending in the X-axis direction and a bent portion 122c connected to both ends of the central portion 122b in the X-axis direction and having a longitudinal direction on the thin-walled portion 96 side. The end on the side of the portion 96 is an end portion 122 a of the slit 122. Therefore, the end portion 122a is disposed closer to the thin portion 96 than the central portion 122b. Further, the groove 126 is formed thinner than the buffer portion 94, and extends in the longitudinal direction from both ends of the slit 122, that is, from the vicinity of the bent portion 122c or the end 122a of the slit 122 to the mount portion 92 side (notch portion 18 side). Formed to have.

  As shown in FIG. 12, the slit 124 formed in the piezoelectric vibrating piece 121 has a shape in which the slit 102 in FIG. 9 is symmetrically inverted about a line parallel to the X axis. The end portion 124a of the slit 124 is disposed closer to the thin portion 96 than the central portion 124b of the slit 124. In FIG. 12, the groove 126 is formed thinner than the buffer portion 94 and has a longitudinal direction from both ends of the slit 124, that is, from the vicinity of the end 122 a to the mount 92 (the notch 18). The

  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. 11 and 12, the extraction electrodes 26 and 30 may also be formed on the side and bottom surfaces of the groove 126.

  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 dig from (the surface side on the −Y′-axis side).

  FIG. 13 and FIG. 14 show the strength distribution of stress when stress is applied to the mount portion of the piezoelectric vibrating piece (type 1, type 2) 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). However, in the piezoelectric vibrating piece (type 1) shown in FIG. 13 and the piezoelectric vibrating piece (type 2) shown in FIG. 14, the ratio between the width of the slit in the X-axis direction and the width of the mount portion in the X-axis direction is They are set differently. That is, in the type 1 piezoelectric vibrating piece, the “mount width / slit width” is set to 94.1%, and in the type 2 piezoelectric vibrating piece, the “mount width / slit width” is set to 82. 4% is set.

  Then, as shown in FIGS. 13 and 14, when two points at the center of the two circles drawn on the mounting surface of the mount part are applied with a pulling force or a pressing force between the two points. The stress distribution of each type of piezoelectric vibrating piece was simulated. The above two points are positions where the conductive adhesive 32 is applied.

  In FIGS. 13 and 14, the patterns arranged in a vertical line on the left side indicate 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, 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 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 FIGS. 13 and 14 will be described in correspondence with the components of the piezoelectric vibrating piece 10 shown in FIG.

  As shown in FIGS. 13 and 14, strong stress (level 9) is generated on the entire mount portion 12 and the mount portion 12 side of the buffer portion 14 in both the type 1 piezoelectric vibration piece and the type 2 piezoelectric vibration piece. I understand. However, the state of relaxation of the stress generated in the mount part 12 from the slit 16 to the connecting part 15, the thick part 17, and the vibrating part 22 is different between Type 1 and Type 2. It can be seen that the type 1 piezoelectric vibrating piece is subjected to level 9 stress in the range of the mounting portion 12 side of the slit 16, the connecting portion 15, and the thick portion 17 due to the stress generated in the mounting portion 12.

  On the other hand, in the type 2 piezoelectric vibrating piece, most of the slit 16 on the side of the mount portion 12 is subjected to level 9 stress, but the region receiving the level 9 stress in the connecting portion 15 is reduced to level 7 level. The region subjected to the stress of 6 becomes dominant. This is because, in the path where the stress generated in the mount portion 12 reaches the connecting portion 15, the bending angle of the path through which the stress propagates is larger in the type 2 piezoelectric vibrating piece than in the type 1 piezoelectric vibrating piece. This is because the relaxation of the stress is promoted as the angle of bending increases.

  Further, in the thick portion 17 of the type 2 piezoelectric vibrating piece, the region receiving the stress of level 7 and level 8 is dominant, but level 8 is particularly dominant. This is presumably because the stress propagating through the connecting portions 15 formed at both ends of the buffer portion 14 in the X-axis direction merges at the thick portion 17.

  Furthermore, in the thick portion 17 of the type 2 piezoelectric vibrating piece, the region receiving the level 7 stress is dominant on the slit 16 side, but the level 8 (partially level 9) stress is applied on the thin portion 21 side. The receiving area is dominant. 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 21 side of the thick portion 17 is bent. As described above, 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.

  Further, the level 9 is dominant in the stress received on the thin portion 21 side of the thick portion 17 of the type 1 piezoelectric vibrating piece, but the stress received in the region of the boundary of the thin portion 21 with the thick portion 17 is Level 7 is dominant. The stress received on the side of the thin portion 21 of the thick portion 17 of the type 2 piezoelectric vibrating piece is dominant at level 8, but the stress received in the boundary region between the thin portion 21 and the thick portion 17 is Level 5 is dominant.

  The large difference in the level of stress received at the boundary between the thick portion 17 and the thin portion 21 occurs in this way because the thin portion 21 is formed thinner than the thick portion 17. This is because the stress that is received is only a part of the stress received by the thick portion 17. Moreover, the thin part 21 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 is also relaxed in the thickness direction of the piezoelectric vibrating piece, so that the thin portion 21 receives only a part of the stress relaxed in the thickness direction by the thick portion 17.

  In the thin portion 21 of the type 1 piezoelectric vibrating piece, the level of stress received as the distance from the boundary with the thick portion 17 decreases, and level 2 is dominant in the central region of the thin portion 21. On the other hand, in the thin portion 21 of the type 2 piezoelectric vibrating piece, the level of stress received as the distance from the boundary with the thick portion 17 decreases, and level 1 is dominant in the central region of the thin portion 21. In the piezoelectric vibrating piece of the present embodiment, the vibrating portion 22 is formed in the central region of the thin portion 21, so that the vibrating portion 22 of the type 2 piezoelectric vibrating piece is hardly affected by stress and obtains good frequency characteristics. It is thought that. Therefore, as in the type 2 piezoelectric vibrating piece shown in FIG. 14, by setting the “mount width / slit width” to be 82.4% or less, it is hardly affected by stress. A piezoelectric vibrating piece having good frequency characteristics can be constructed.

  As described above, any of the piezoelectric vibrating pieces described in the embodiments is an inverted mesa type piezoelectric vibrating piece configured such that the short side direction of the vibrating portion (thin wall portion) 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 it is needless to say that the present invention can also be applied to an inverted mesa type piezoelectric vibrating piece configured such that the short side direction of the vibrating portion is the Z′-axis direction and the long side direction is the X-axis direction. Yes.

  FIG. 15 is a schematic diagram of a piezoelectric vibrator equipped with the piezoelectric vibrating piece of the present embodiment, FIG. 15A is a plan view of the piezoelectric vibrator when the piezoelectric vibrating piece shown in FIG. FIG. 15B is a cross-sectional view taken along 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 extraction electrodes 26 and 30 of 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.

  16 and 17 show an electronic device on which the piezoelectric vibrating piece according to this embodiment is mounted. FIG. 16 is an exploded perspective view of an electronic device on which the piezoelectric vibrating piece 10 shown in FIG. 1 is mounted. FIG. 17 is a schematic diagram of an electronic device on which the piezoelectric vibrating piece according to this embodiment is mounted. FIG. 17A is a cross-sectional view taken along the line AA when the piezoelectric vibrating piece 60 shown in FIG. FIG. 17B is a cross-sectional view taken along line AA when the piezoelectric vibrating piece 61 shown in FIG. 7 is mounted in FIG.

  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. A connection electrode 318 is formed on the upper step 308 of the recess 304 of the package 302 to connect to the extraction electrodes 26 and 30 of the piezoelectric vibrating reeds 10, 60 and 61 via the conductive adhesive 32.

  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 extraction electrodes 26 and 30 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 piece is relaxed is obtained.

  FIG. 18 shows a schematic diagram of a first modification of the electronic device of the present embodiment. In FIG. 18, 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 extraction electrodes 26 and 30 of the piezoelectric vibrating piece 60 via 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. 19 shows a schematic diagram of a second modification of the electronic device of the present embodiment. FIG. 19A is a side view, and FIG. 19B is a plan view of a substrate constituting the electronic device. In the second modification, for example, the electronic device 500 is formed using the 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.

10 ......... Piezoelectric vibrating piece, 10a ......... Piezoelectric element plate, 11 ......... Piezoelectric element plate, 12 ......... Mount part, 14 ......... Buffer part, 15 ......... Connecting part, 16 ......... Slit , 17 ......... Thick part, 18 ... ... Notch part, 21 ... ... Thin part, 21a ... ... Recessed part, 22 ... ... Vibrating part, 24 ... ... Excitation electrode, 26 ... ... Extraction electrode 28 ......... Excitation electrode, 30 ......... Extraction electrode, 32 ......... Conductive adhesive, 34 ......... Substrate, 36 ......... Quartz substrate, 38 ......... Resist film, 38a ...... Resist film , 40... Photomask 42... Resist film 42 a ... Resist film 44... Photomask 46 46 Metal film 48 Resist film 48 a Resist film 50... Photomask 60... Piezoelectric vibrating piece 61 61 Piezoelectric vibrating piece 62 62 Mount 64 ......... Buffer part, 70 ... ... Thick part, 71 ... ... Thin part, 72 ... ... Mesa part, 74 ... ... Excitation electrode, 76 ... ... Excitation electrode, 78 ... ... Thin part, 80 ......... Mesa portion, 90 ......... Piezoelectric vibrating piece, 91 ......... Piezoelectric vibrating piece, 92 ......... Mount portion, 94 ......... Buffer portion, 96 ......... Thin portion, 98 ......... Vibrating portion 100 ......... Slit, 100a ......... End, 100b ......... Center, 100c ......... Bent, 100d ......... Normal, 102 ......... Slit, 102a ......... End, 102b ... ...... Center part, 102c ......... Normal, 110 ......... Piezoelectric vibrating piece, 112 ......... Reinforcing part, 120 ......... Piezoelectric vibrating piece, 121 ......... Piezoelectric vibrating piece, 122 ......... Slit, 122a ......... End, 122b ......... Center, 122c ......... Bent, 124 ......... Slit, 124 ......... End, 124b ......... Center, 126 ......... Groove, 200 ......... Piezoelectric vibrator, 202 ......... Package, 204 ......... Recess, 206 ......... External electrode, 208 ......... Through electrode, 210... Connection electrode, 212... Lid, 214... Extraction electrode, 215... Extraction electrode, 300... Electronic device, 302. ......... Lower part, 308 ......... Upper part, 310 ......... IC, 312 ......... Lid, 314 ...... External electrode, 316 ......... Connection electrode, 318 ......... Connection electrode, 320 ......... Pad electrode, 322 ......... Adhesive, 400 ......... Electronic device, 402 ......... Package, 404 ......... Recess, 406 ...... Recess, 408 ...... Lid, 410 ...... External electrode, 412 ... ...... Connection electrode, 414 ......... Ear, 416 ... 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 ... Through electrode 600 ... Piezoelectric vibrator 602 ... Supporting part, 604 ......... Vibration part, 606A ......... Excitation electrode part, 606B ......... Excitation electrode part, 608A ......... Input / output terminal part, 608B ......... Input / output terminal part, 610 ......... Slit , 612 ......... Container, 614 ... ... Bottom, 616 ... ... Adhesive, 700 ... ... Piezoelectric vibrating piece, 702 ... ... Mount part, 704 ... ... Slit, 706 ... ... Vibrating part, 708 ... ... notches, 710 ... Part.

Claims (10)

A piezoelectric vibrating piece provided with a thin part having a vibration part and a thick part provided on the periphery of the thin part and thicker than the thin part,
The thick part is connected to the mount part side by side through a buffer part,
The buffer part has a slit between the mount part and the thick part,
The mount part is
Notch portions are 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 longitudinal direction of the slit is parallel to the orthogonal direction,
The width in the orthogonal direction of the mount portion is narrower than the width in the longitudinal direction of the slit,
Both ends of the slit in the longitudinal direction are closer to the outer periphery in the orthogonal direction of the buffer than the both ends of the mount.   2. The piezoelectric vibrating piece according to claim 1, wherein 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. .   3. The piezoelectric vibration according to claim 1, wherein the slit is provided with a reinforcing portion that is thinner than the buffer portion and extends from the both end portions of the slit toward a central portion of the slit. Piece. 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,
2. The piezoelectric vibrating piece according to claim 1, wherein a groove extending from the both end portions toward the notch is formed between the both ends and the notch.   Centering on the X axis of an orthogonal coordinate system consisting of 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 the Y axis. The axis tilted in the -Y direction is the Z 'axis, the Y axis is tilted in the + Z direction of the Z axis as the Y' axis, and is composed of planes parallel to the X axis and the Z 'axis. 5. The piezoelectric vibrating piece according to claim 1, comprising an AT-cut quartz crystal having a thickness in a direction parallel to the Y ′ axis. Excitation electrodes are arranged on both main surfaces of the vibration part,
On the mounting surface of the mount part, a pair of extraction electrodes each electrically connected to the excitation electrode is disposed,
6. The piezoelectric vibrating piece according to claim 1, wherein the thin portion is connected to the thick portion with a bias toward a main surface opposite to the mounting surface.   The piezoelectric vibrating piece according to claim 1, wherein the vibrating portion is thicker than the thin portion. Having a substrate,
The piezoelectric vibrating piece according to claim 1, wherein a mounting surface of the mounting portion of the piezoelectric vibrating piece according to claim 1 is directed to the substrate side, and the mounting portion and the substrate are bonded with a conductive adhesive. A piezoelectric vibrator characterized by being mounted. Having a substrate,
The piezoelectric vibrating piece according to claim 1, wherein a mounting surface of the mounting portion of the piezoelectric vibrating piece according to claim 1 is directed to the substrate side, and the mounting portion and the substrate are bonded with a conductive adhesive. And an electronic device comprising at least one electronic component.   The electronic device according to claim 9, wherein the electronic component is one of a thermistor, a capacitor, a reactance element, and a semiconductor element.

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