JP2013046189A - Piezoelectric vibration element, piezoelectric vibrator, electronic device, and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact high-frequency piezoelectric vibration element that has a small CI value and suppresses nearby spurious frequencies while using a fundamental wave.SOLUTION: A piezoelectric vibration element 1 includes: a piezoelectric substrate 10 that has a rectangular vibration region 12 and a support portion 13; excitation electrodes 25a and 25b; and lead electrodes 27a and 27b. The support portion 13 includes a first support portion 14, a second support portion 15, a third support portion 16, and a fourth support portion. The second support portion 15 has a second inclined portion 15b and a second support portion main body 15a. The second support portion 15 is provided with at least one slit 20.

Description

  The present invention relates to a piezoelectric vibrator that excites a thickness shear vibration mode, and more particularly, to a piezoelectric vibration element, a piezoelectric vibrator, an electronic device, and an electronic device using the piezoelectric vibrator having a so-called inverted mesa structure.

AT-cut quartz resonators have thickness shear vibration as the main vibration mode to be excited, and are suitable for miniaturization and higher frequency, and exhibit a cubic curve with excellent frequency temperature characteristics. Used in many ways.
Patent Document 1 discloses an AT-cut crystal resonator having a so-called inverted mesa structure in which a concave portion is formed on a part of a main surface to increase the frequency. A so-called Z ′ long substrate is used in which the length in the Z′-axis direction of the quartz substrate is longer than the length in the X-axis direction.
Patent Document 2 discloses an AT-cut quartz resonator having an inverted mesa structure in which a thick support portion is connected to three sides of a rectangular thin vibration portion, and one side of the thin vibration portion is exposed. Is disclosed. Further, the quartz crystal resonator piece is an in-plane rotated AT-cut quartz substrate formed by rotating the X-axis and the Z′-axis of the AT-cut quartz substrate in the range of −120 ° to + 60 ° around the Y′-axis, It is said to be a structure that secures a vibration region and is excellent in mass productivity (multiple picking).

In Patent Documents 3 and 4, an AT-cut crystal having an inverted mesa structure in which a thick support portion is connected to three sides of a rectangular thin vibration portion, and one side of the thin vibration portion is exposed. A resonator is disclosed, and a so-called X long substrate in which the length in the X-axis direction of the quartz crystal substrate is longer than the length in the Z′-axis direction is used as the quartz crystal resonator element.
In Patent Document 5, a thick support portion is connected to two adjacent sides of a rectangular thin vibration portion, and a thick portion is provided in an L shape in plan view. An AT-cut crystal resonator having an inverted mesa structure having a structure in which two sides are exposed is disclosed. A Z ′ long substrate is used as the quartz substrate.
However, in Patent Document 5, in order to obtain an L-shaped thick portion, as described in FIGS. 1 (c) and 1 (d) of Patent Document 5, along the line segment α and the line segment β. The thick part is deleted, but the deletion is based on the premise that it will be deleted by machining such as dicing, so the chipping or cracking damage will occur on the cut surface, and the ultra thin part will be damaged. There is. In addition, problems such as generation of unnecessary vibration that causes spurious noise and an increase in CI value occur in the vibration region.
Patent Document 6 discloses an AT-cut crystal resonator having an inverted mesa structure having a structure in which a thick support portion is connected to only one side of a thin vibration portion and three sides of the thin vibration portion are exposed. Yes.

Patent Document 7 discloses an AT-cut vibrator having an inverted mesa structure in which a concave portion is formed so as to be opposed to each other on both main surfaces and front and back surfaces of a quartz substrate. An X long substrate is used as the quartz substrate, and a structure is proposed in which excitation electrodes are provided in a region where the flatness of the vibration region formed in the recessed portion is ensured.
By the way, it is known that the thickness-shear vibration mode excited in the vibration region of the AT-cut crystal resonator has an elliptical shape in which the vibration displacement distribution has a major axis in the X-axis direction due to the anisotropy of the elastic constant. Patent Document 8 discloses a piezoelectric vibrator that excites thickness-shear vibration having a pair of ring-shaped electrodes arranged symmetrically on the front and back surfaces of a piezoelectric substrate. The difference between the outer peripheral diameter and the inner peripheral diameter of the ring electrode is set so that the ring electrode excites only the symmetrical zero-order mode and hardly excites the other nonharmonic higher-order modes.

Patent Document 9 discloses a piezoelectric vibrator in which the shape of a piezoelectric substrate and excitation electrodes provided on the front and back surfaces of the piezoelectric substrate are both elliptical.
Patent Document 10 discloses that both ends of the quartz substrate in the longitudinal direction (X-axis direction) and both ends of the electrode in the X-axis direction are semi-elliptical, and the ratio of the major axis to the minor axis of the ellipse (long) A crystal resonator having an axis / short axis) of approximately 1.26 is disclosed.
Patent Document 11 discloses a crystal resonator in which an elliptical excitation electrode is formed on an elliptical crystal substrate. The ratio of the major axis to the minor axis is preferably 1.26: 1, but considering the variation in manufacturing dimensions, the range of 1.14 to 1.39: 1 is practical.

Patent Document 12 discloses a piezoelectric vibrator having a structure in which a notch or a slit is provided between a vibrating part and a support part in order to further improve the energy confinement effect of the thickness-slip piezoelectric vibrator.
By the way, when the piezoelectric vibrator is miniaturized, there is a case where the electrical characteristics are deteriorated or the frequency aging characteristics are deteriorated due to the residual stress caused by the adhesive. Patent Literature 13 discloses a crystal resonator in which a notch or a slit is provided between a vibrating portion and a support portion of a rectangular flat plate AT-cut crystal resonator. By using such a structure, it is possible to suppress the residual stress from spreading to the vibration region.
Patent Document 14 discloses a vibrator in which a notch or a slit is provided between a vibrating portion and a support portion of an inverted mesa piezoelectric vibrator in order to improve (relax) mount strain (stress). . Patent Document 15 discloses a piezoelectric vibrator in which conduction between electrodes on the front and back surfaces is ensured by providing a slit (through hole) in a support portion of an inverted mesa piezoelectric vibrator.

Patent Document 16 discloses a crystal resonator that suppresses an unnecessary mode of a higher-order contour system by providing a slit in a support portion of an AT-cut crystal resonator in a thickness shear vibration mode.
Further, in Patent Document 17, a spurious structure is provided by providing a slit in a connecting portion of a thin vibrating portion of an inverted mesa AT-cut crystal resonator and a thick holding portion, that is, a residue portion having an inclined surface. A vibrator that suppresses the above is disclosed.

JP 2004-165743 A JP 2009-164824 A JP 2006-203700 A JP 2002-198772 A JP 2002-033640 A JP 2001-144578 A JP 2003-264446 A JP-A-2-079508 JP 9-246903 A JP 2007-158486 A JP 2007-214941 A Japanese Utility Model Publication No. 61-187116 Japanese Patent Laid-Open No. 9-326667 JP 2009-158999 A JP 2004-260695 A JP 2009-188483 A JP 2003-087087 A

In recent years, there has been a strong demand for miniaturization, high frequency, and high performance of piezoelectric devices. However, the piezoelectric vibrator having the above-described structure has the CI value of the main vibration and the adjacent spurious CI value ratio (= CIs / CIm, where CIm is the CI value of the main vibration, and CIs is the CI value of the spurious. It has been found that there is a problem that one example cannot satisfy the requirement.
Therefore, the present invention has been made to solve the above-described problem, and has achieved high frequency (100 to 500 MHz band), reduced the CI value of the main vibration, and satisfied electrical requirements such as a spurious CI value ratio. It is an object of the present invention to provide a piezoelectric vibration element, a piezoelectric vibrator, an electronic device, and an electronic apparatus using the piezoelectric vibrator of the present invention.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A piezoelectric vibration element according to the present invention includes a piezoelectric substrate having a vibration part including a vibration region, and a support part that is integrated with the vibration part and is thicker than the thickness of the vibration part. A piezoelectric vibration element having a pair of excitation electrodes disposed so as to face each other on the front and back sides, wherein the support portion is configured to move the vibration portion along two opposite sides of the main surface of the vibration portion. A first support portion and a second support portion, which are respectively provided so as to be sandwiched, a third support portion which continuously connects one end of each of the first and second support portions, and the first And a fourth support part that continuously connects the other end of each of the second support parts, and the front and back main surfaces of the first and second support parts are the front and back main surfaces of the vibration part And one main surface of the third support portion protrudes from one main surface of the vibration portion, and the other main surface of the third support portion. And the other main surface of the vibration part are the same surface, and one main surface of the fourth support part protrudes from the other main surface of the vibration part, and the other main surface of the fourth support part The piezoelectric vibration element is characterized in that the principal surface of the first vibration member and the one principal surface of the vibration part are the same surface.

  According to this configuration, there is an effect that the piezoelectric vibration element having a high frequency and a fundamental wave is miniaturized, and the support of the vibration region is strengthened, so that a piezoelectric vibration element resistant to vibration, impact, and the like can be obtained. Furthermore, by providing a slit, it is possible to suppress the spread of stress due to adhesion / fixing, so that the frequency temperature characteristic, the CI temperature characteristic, and the frequency aging characteristic are excellent, and the CI value of the main vibration is small. There is an effect that a piezoelectric vibration element having a large ratio of the CI value of adjacent spurious to the CI value of vibration, that is, a large CI value ratio can be obtained.

  Application Example 2 In the piezoelectric vibration element, the piezoelectric substrate includes orthogonal coordinates including an X axis as an electric axis that is a crystal axis of quartz, a Y axis as a mechanical axis, and a Z axis as an optical axis. Centering on the X axis of the system, the Z axis is inclined by a predetermined angle in the −Y direction of the Y axis as a Z ′ axis, and the Y axis is only in the + Z direction of the Z axis by the predetermined angle. An application example 1 is characterized in that the inclined substrate is a quartz substrate having a Y′-axis, a plane parallel to the X-axis and the Z′-axis, and having a thickness in a direction parallel to the Y′-axis. It is a piezoelectric vibration element of description.

  According to this configuration, there is an effect that it is possible to configure a required specification with a more suitable cut angle and frequency, and to obtain a high-frequency fundamental wave piezoelectric vibration element having a frequency temperature characteristic according to the specification.

  Application Example 3 In the piezoelectric vibration element, the protruding portion of the third support portion is on the plus side of the Z ′ axis, and the protruding portion of the fourth support portion is on the Z ′ axis. The piezoelectric vibration element according to Application Example 2, which is on the minus side.

  According to this configuration, there is an effect that the projecting portion enhances the impact resistance and vibration resistance of the piezoelectric vibration element.

  Application Example 4 In the piezoelectric vibration element, the second inclined portion whose thickness increases as the second support portion moves away from one end edge connected to the vibration portion toward the other end edge. And a second support portion main body provided continuously with the other edge of the second inclined portion, wherein the piezoelectric vibration element according to any one of application examples 1 to 3 is provided. .

  According to this configuration, there is an effect that a piezoelectric vibration element having a high frequency and a fundamental wave is miniaturized, and the vibration part is firmly supported, and a piezoelectric vibration element that is strong against vibration, impact, and the like can be obtained.

  Application Example 5 In the piezoelectric vibration element according to Application Example 4, it is preferable that the second support portion is provided with at least one slit.

  According to this configuration, since it is possible to suppress the spread of stress that occurs when the piezoelectric vibration element is bonded and fixed, it is possible to obtain a piezoelectric vibration element having excellent frequency temperature characteristics, CI temperature characteristics, and frequency aging characteristics. There is.

  Application Example 6 In the piezoelectric vibration element, the slit is disposed in the second support portion main body along a boundary portion between the second inclined portion and the second support portion main body. The piezoelectric vibration element according to Application Example 5 which is characterized.

  According to this configuration, since it is possible to suppress the spread of stress that occurs when the piezoelectric vibration element is bonded and fixed, it is possible to obtain a piezoelectric vibration element having excellent frequency temperature characteristics, CI temperature characteristics, and frequency aging characteristics. There is.

  Application Example 7 In the piezoelectric vibration element according to Application Example 5, in which the slit is disposed in the second inclined portion so as to be separated from one side of the vibration region. is there.

  According to this configuration, the slit can be easily formed and the spread of stress generated when the piezoelectric vibration element is bonded and fixed can be suppressed. Therefore, the piezoelectric vibration element having excellent frequency temperature characteristics and CI temperature characteristics can be obtained. There is an effect that it is obtained.

  Application Example 8 In the piezoelectric vibration element, the slit is disposed apart from one side of the vibration region in the second inclined portion and the first slit disposed in the second support body. In addition, the piezoelectric vibration element according to Application Example 5 is provided with a second slit.

  According to this configuration, by providing two slits in the second support portion, it is possible to better suppress the spread of stress that occurs when the piezoelectric vibration element is bonded and fixed. The piezoelectric vibration element is excellent in temperature characteristics, CI temperature characteristics, and frequency aging characteristics.

  Application Example 9 In the piezoelectric vibration element, the first slit is disposed in the second support portion body along a boundary portion between the second inclined portion and the second support portion body. It is a piezoelectric vibration element as described in the application example 8 characterized by the above-mentioned.

  According to this configuration, since the first slit is provided along the boundary portion between the second inclined portion and the second support portion main body, the spread of stress generated when the piezoelectric vibration element is bonded and fixed can be reduced. Further, since it can be further strongly suppressed, there is an effect that a piezoelectric vibration element can be obtained that is excellent in frequency reproducibility, frequency temperature characteristics, CI temperature characteristics, and frequency aging characteristics.

  Application Example 10 A piezoelectric vibrator according to the present invention includes the piezoelectric vibration element according to any one of application examples 1 to 9, and a package that accommodates the piezoelectric vibration element. This is a piezoelectric vibrator.

  According to this configuration, since the piezoelectric vibrator of the fundamental wave at high frequency can be miniaturized and stress caused by adhesion / fixation can be suppressed, frequency reproducibility, frequency temperature characteristics, CI temperature characteristics, and frequency There is an effect that a piezoelectric vibrator having excellent aging characteristics can be obtained. Furthermore, the CI value of the main vibration is reduced, and the ratio of the spurious CI value to the CI value of the main vibration, that is, a piezoelectric vibration element having a large CI value ratio, and a piezoelectric vibrator having a small capacitance ratio are obtained. effective.

  Application Example 11 An electronic device according to the present invention is an electronic device characterized in that the package includes the piezoelectric vibration element according to any one of Application Examples 1 to 9 and an electronic component. .

  According to this configuration, by selecting an electronic device based on customer requirements, the characteristics of the piezoelectric vibration element of the present invention can be utilized. For example, frequency reproducibility, frequency temperature characteristics, aging characteristics are excellent, and small size In addition, an electronic device having a high frequency (for example, 490 MHz band) can be obtained.

  Application Example 12 In the electronic device according to Application Example 11, the electronic component is any one of a variable capacitance element, a thermistor, an inductor, and a capacitor.

  As described above, when an electronic device (piezoelectric device) is configured using any one of a variable capacitance element, a thermistor, an inductor, and a capacitor, an electronic device suitable for the required specifications can be realized in a small size and at low cost. effective.

  Application Example 13 In the electronic device according to Application Example 11 or 12, the electronic device includes an oscillation circuit that excites the piezoelectric vibration element in the package.

  According to this configuration, electronic devices such as a piezoelectric oscillator, a temperature compensation type piezoelectric oscillator, and a voltage control type piezoelectric oscillator can be configured with a fundamental wave and a high frequency. In addition, when a voltage-controlled piezoelectric oscillator is configured, an electronic device having excellent frequency reproducibility and aging characteristics, a wide frequency variable range due to the use of a fundamental wave, and an excellent S / N ratio (signal-to-noise ratio) can be obtained. effective.

  Application Example 14 An electronic apparatus according to the present invention is an electronic apparatus including the piezoelectric vibrator according to Application Example 10.

  According to this configuration, by using the piezoelectric vibrator of the present invention for an electronic device, there is an effect that an electronic device including a reference frequency source having a high frequency and excellent frequency stability and a good S / N ratio can be configured. .

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which showed the structure of the piezoelectric vibration element 1 of the example of 1st Embodiment, (a) is a top view, (b) is sectional drawing which looked at the PP cross section from + X-axis direction, c) is a cross-sectional view of the QQ cross section viewed from the -Z 'direction. The figure explaining the relationship between an AT cut quartz substrate and a crystal axis. The top view which shows the structure of the modification of a piezoelectric vibration element. The top view which shows the structure of the other modification of a piezoelectric vibration element. It is the schematic which showed the structure of the piezoelectric vibration element 2 of 2nd Example, (a) is a top view, (b) is sectional drawing which looked at the PP cross section from + X-axis direction, c) is a cross-sectional view of the QQ cross section viewed from the -Z 'direction. It is the schematic which showed the structure of the piezoelectric vibration element 3 of the example of 3rd Embodiment, (a) is a top view, (b) is sectional drawing which looked at the PP cross section from + X-axis direction, c) is a cross-sectional view of the QQ cross section viewed from the -Z 'direction. (A) And (b) is a top view which shows the structure of the modification of the example of 3rd Embodiment. The manufacturing process figure which shows the manufacturing process of the piezoelectric substrate of this invention. The manufacturing process figure of the excitation electrode and lead electrode of the piezoelectric vibration element of this invention. (A) is a top view of the recessed part formed in the piezoelectric wafer, (b)-(e) is a figure explaining the cut surface (cut surface) of the cross section of the X-axis direction of a recessed part and a groove part. (A) is a top view of the recessed part formed in the piezoelectric wafer, (b)-(e) is sectional drawing explaining the cut surface of one cross section of a Z 'axis direction of a recessed part and a groove part. (A) is a perspective view which shows the structure of the piezoelectric vibration element 1 of the example of 1st Embodiment, (b) is a detailed cutaway figure of the QQ cross section of FIG. The figure which shows the cut surface of the QQ cross section of the piezoelectric vibration element of the example of 4th Embodiment. It is a figure which shows the structure of the piezoelectric vibrator 5 which concerns on this invention, Comprising: (a) is a longitudinal cross-sectional view, (b) is a top view except the cover part. It is a figure which shows the structure of the modification of the piezoelectric vibrator 5, Comprising: (a) is a longitudinal cross-sectional view, (b) is a top view except the cover part. The longitudinal cross-sectional view of the electronic device (piezoelectric device) 6 which concerns on this invention. (A) of the electronic device (piezoelectric device) 7 concerning this invention is a longitudinal cross-sectional view, (b) is a top view. The longitudinal cross-sectional view of the modification of the electronic device 7. FIG. FIG. (A)-(c) is a perspective view of the modification of the piezoelectric substrate which concerns on this invention. (A)-(c) is a perspective view of the modification of the piezoelectric substrate which concerns on this invention. It is a modification of the piezoelectric vibration element 1 which concerns on this invention, (a) is a top view, (b) is an enlarged view of the principal part, (c) is the sectional drawing.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing a configuration of a piezoelectric vibration element according to an embodiment of the present invention. FIG. 4A is a plan view, FIG. 4B is a cross-sectional view of the PP cross section viewed from the + X-axis direction, and FIG. 4C is a cross-sectional view of the QQ cross section viewed from the + Z ′ direction.
The piezoelectric vibration element 1 includes a thin vibration region 12, a piezoelectric substrate 10 having a thick support portion 13 connected to the vibration region 12, and excitation electrodes formed to face both main surfaces of the vibration region 12. 25a, 25b, lead electrodes 27a, 27b formed to extend from the excitation electrodes 25a, 25b to the thick portion support portion 13, respectively, and pad electrodes 29a, 29b connected to the terminal ends of the lead electrodes 27a, 27b, It has. Here, the vibration region means a region where the vibration energy is confined, that is, the inside of the region where the vibration energy is almost zero, and the size of the vibration region in the X-axis direction and the size of the vibration region in the Z′-axis direction are As is well known, the ratio is 1.26: 1. Further, the vibration part refers to the entire piezoelectric substrate including the vibration area and its peripheral part.

The piezoelectric substrate 10 includes a vibration part 12 in a rectangular and thin flat plate-like vibration region, and a square annular thick support part 13 integrated along the four sides of the periphery of the vibration part 12.
The thick support portion 13 includes a first support portion 14 and a second support portion 15 that protrude from the main surfaces of the vibration region 12 along two opposite sides 12a and 12b. The third support is formed by connecting one end portion of each of the first and second support portions 14 and 15 on one main surface side (surface side) of the vibration region 12 and projecting only on the surface side. And a fourth support portion 17 that protrudes along the other main surface side (back surface side) of the other side 12d of the vibration region 12 that faces the third support portion 16. The two sides 12a and 12b are sides arranged in parallel with the vibration region 12 in between.

The first support portion 14 is connected to one side 12a of the thin flat plate-like vibration region 12 and protrudes from both main surfaces. In addition, the first inclined portion 14b whose thickness gradually increases as the distance from the one side 12a of the vibration region 12 increases, and the thick quadrangular columnar first support portion main body 14a that is connected to the other end edge of the first inclined portion 14b. And. That is, as shown in FIG. 1C, the first support portion 14 is formed to project from both main surfaces (front surface and back surface) of the vibration region 12.
Similarly, the second support portion 15 is connected to one side 12b of the thin flat plate-like vibration region 12 and protrudes from both main surfaces. A second inclined portion 15b having a thickness that gradually increases as it is separated from one side 12b of the vibration region 12, and a second support portion main body 15a having a thick quadrangular column shape that is connected to the other end edge of the second inclined portion 15b. And. In other words, as shown in FIG. 1C, the second support portion 15 is formed so as to project on both surfaces (front surface and back surface) of the main surface of the vibration region 12. The support body (first and second support bodies 14a, 15a, etc.) refers to a region having a constant thickness parallel to the Y ′ axis.

The third support portion 16 is connected to one side 12c of the vibration region 12 on the surface side of the thin flat plate-like vibration region 12, and has a third inclined portion 16b whose thickness gradually increases as the distance from the one side 12c increases to the outside. And a thick quadrangular columnar third support portion body 16a provided continuously with the other end edge of the third inclined portion 16b. That is, one main surface of the third support portion 16 is formed so as to protrude from one main surface (surface) of the vibration region 12. The other main surface of the third support portion 16 and the other main surface of the vibration portion are continuously connected to each other and are configured to be the same surface. Even in the case where there is a protruding energy confinement region on the mesa in the vibration region, the main surface of the peripheral portion of the vibration region is continuously connected to the other main surface of the third support portion, and the same What is necessary is just to be comprised so that it may become a surface.
The fourth support portion 17 is connected to the one side 12d of the vibration region 12 so as to face the third support portion 16 on the back surface side of the thin vibration region 12, and as the fourth support portion 17 is separated from the one side 12d of the vibration region 12. A fourth inclined portion 17b having a gradually increasing thickness, and a fourth support portion main body 17a having a thick quadrangular columnar shape provided continuously to the other end edge of the fourth inclined portion 17b are provided. Further, the fourth support portion 17 connects the other end portions of the first support portion 14 and the second support portion 15 on the back surface side of the vibration region. That is, one main surface of the fourth support portion 17 is formed so as to protrude from the other main surface (back surface) of the vibration region 12. The other main surface of the fourth support portion 17 and one main surface of the vibration portion are continuously connected to each other and are configured to be the same surface. Even when there is a protruding energy confinement region on the mesa in the vibration region, the peripheral surface of the vibration region is continuously connected to the other main surface of the fourth support portion 17, What is necessary is just to be comprised so that it may become the same surface.
The third support portion 16 and the fourth support portion 17 are in a point-symmetric relationship with respect to the midpoint of the vibration region 12, and the first, second, third, and fourth support portions are at their respective ends. The parts are connected to form a square ring, and the vibration region 12 is held at the center.

The substantially rectangular vibration region 12 is surrounded by first, second, third, and fourth support portions 14, 15, 16, and 17 on the four sides of the periphery. That is, etching is performed from both main surfaces of the rectangular flat plate-shaped piezoelectric substrate, two concave portions facing both the main surfaces are formed, unnecessary portions are cut to reduce the size, and the thin vibration region 12 is formed. Forming.
Further, in the piezoelectric substrate 10, at least one stress relaxation slit 20 is formed through the second support portion 15. In the embodiment shown in FIG. 1, the slit 20 is formed in the plane of the second support body 16a along the boundary (joint portion) between the second inclined portion 16b and the second support body 16a. Has been.
Thus, since the slit 20 is disposed close to the boundary portion (joining portion) of the second support body 15a, a large area of the supported portion (pad electrode) 29a of the second support portion body 15a is ensured. The diameter of the conductive adhesive to be applied can be increased. On the other hand, when the slit 20 is disposed closer to the supported portion (pad electrode) 29a of the second support body 15a, the area of the supported portion (pad electrode) 29a is reduced, and the diameter of the conductive adhesive is reduced. Must be reduced. As a result, the absolute amount of the conductive filler contained in the conductive adhesive is also reduced, the conductivity is deteriorated, the resonance frequency of the piezoelectric vibration element 1 is not stabilized, and the frequency fluctuation (commonly referred to as F jump) is likely to occur. There is.
Therefore, it is preferable that the slit 20 is arranged close to the boundary portion (joint portion) of the second support body 15a.
In addition, one surface (surface) of each of the first and second support bodies 14a and 15a and one surface (surface) of the third support body 16a are on the same plane, and the first and second surfaces are the same. The other surface (back surface) of each of the support bodies 14a and 15a and the surface (back surface) of the fourth support body 17a are on the same plane.

  A piezoelectric material such as quartz belongs to the trigonal system and has crystal axes X, Y, and Z orthogonal to each other as shown in FIG. The X axis, the Y axis, and the Z axis are referred to as an electric axis, a mechanical axis, and an optical axis, respectively. The AT-cut quartz crystal substrate 10 is a flat plate cut out from the quartz crystal along a plane obtained by rotating the XZ plane around the X axis by an angle θ. In the case of the AT-cut quartz substrate 10, θ is approximately 35 ° 15 ′. Note that the Y-axis and the Z-axis are also rotated by θ around the X-axis to be the Y′-axis and the Z′-axis, respectively. Accordingly, the AT cut quartz crystal substrate 10 has orthogonal crystal axes X, Y ′, and Z ′. The AT-cut quartz substrate 10 has a thickness direction of the Y ′ axis, an XZ ′ plane (a plane including the X axis and the Z ′ axis) orthogonal to the Y ′ axis is a main surface, and thickness shear vibration is the main vibration. Excited.

As shown in FIG. 2, an example of the piezoelectric substrate 10 includes an X-axis of an orthogonal coordinate system composed of an X-axis (electrical axis), a Y-axis (mechanical axis), and a Z-axis (optical axis). The axis tilted in the −Y direction is the Z ′ axis, the Y axis is the Y ′ axis is the axis tilted in the + Z direction of the Z axis, and is composed of surfaces parallel to the X and Z ′ axes. This is an AT-cut quartz substrate having a thickness in a parallel direction.
The piezoelectric substrate according to the present invention is not limited to the AT cut with the angle θ of approximately 35 ° 15 ′, but can be widely applied to a piezoelectric substrate such as a BT cut that excites thickness shear vibration. Needless to say.

As shown in FIG. 1A, the piezoelectric substrate 10 has a direction parallel to the X axis (hereinafter referred to as “X axis”) with a direction parallel to the Y ′ axis (hereinafter referred to as “Y ′ axis direction”) as a thickness direction. It has a rectangular shape having a long side as a “direction” and a short side as a direction parallel to the Z ′ axis (hereinafter referred to as “Z ′ direction”).
In the embodiment shown in FIG. 1, the excitation electrodes 25 a and 25 b that drive the piezoelectric substrate 10 have a quadrangular shape, and are formed so as to face both the front and back surfaces of the substantially central portion of the vibration region 12. As shown in FIG. 1B, the area of the excitation electrode 25b on the back surface side is set sufficiently larger than the area of the excitation electrode 25a on the front surface side. This is because the energy confinement coefficient due to the mass effect of the excitation electrode is not increased more than necessary. That is, by sufficiently increasing the area of the excitation electrode 25b on the back surface side, the plate back amount Δ (= (fs−fe) / fs, where fs is the cutoff frequency of the piezoelectric substrate, and fe is excited on the entire surface of the piezoelectric substrate. The frequency when the electrode is attached depends only on the mass effect of the excitation electrode 25a on the surface side.

The excitation electrodes 25a and 25b are formed by depositing nickel (Ni) on a base and depositing gold (Au) thereon using a vapor deposition apparatus or a sputtering apparatus. The thickness of the gold (Au) is within a range in which the ohmic cross does not increase, and only the main vibration is set as the confinement mode (S0), and the oblique symmetric inharmonic mode (A0, A1,...) And the symmetric inharmonic mode (S1, S3,. •)) should not be in confinement mode. However, for example, in a piezoelectric vibration element of 490 MHz band, it is inevitable that a low-order inharmonic mode is confined to some extent when a film is formed so as to avoid ohmic crossing of the electrode film thickness.
The excitation electrode 25a formed on the surface side is formed on the surface of the second support portion main body 15a by the lead electrode 27a passing from the vibration region 12 through the third inclined portion 16b and the third support portion main body 16a. The pad electrode 29a is electrically connected. In addition, the excitation electrode 25b formed on the back surface side of the second support portion main body 15a is formed by the lead electrode 27b passing from the vibration region 12 through the fourth inclined portion 17b and the fourth support portion main body 17a. The pad electrode 29b formed on the back surface is conductively connected.

The embodiment shown in FIG. 1A is an example of a lead-out structure of the lead electrodes 27a and 27b, and the lead electrode 27a may pass through another support portion. However, it is desirable that the length of the lead electrodes 27a and 27b is the shortest, and it is desirable to suppress an increase in capacitance by considering that the lead electrodes 27a and 27b do not cross each other. The increase in capacitance deteriorates the capacitance ratio γ (ratio of parallel capacitance (capacitance) C0 to series capacitance (motional capacitance) C1) of the piezoelectric vibration element 1.
In the embodiment shown in FIG. 1, an example is shown in which the pad electrodes 29 a and 29 b are formed in proximity to both the front and back surfaces of the piezoelectric substrate 10. When the piezoelectric vibration element 1 is accommodated in the package, the piezoelectric vibration element 1 is turned over, the pad electrode 29a is fixed, and the pad electrode 29b and the electrode terminal of the package are connected by a bonding wire. Thus, when the site | part to support becomes one point, it is possible to make small the stress resulting from a conductive adhesive.
Further, the pad electrodes 29a and 29b of the piezoelectric vibration element 1 may be formed with a larger interval than the above example.

The reason why the slit 20 is provided between the vibration region 12 and the pad electrodes 29a and 29b that are supported portions of the piezoelectric vibration element 1 is to prevent the spread of stress generated when the conductive adhesive is cured.
That is, when the pad electrode of the piezoelectric vibration element is supported on the package using the conductive adhesive, first, the conductive adhesive is applied to the supported portion (pad electrode) 29a of the second support portion main body 15a, This is reversed and placed on an element mounting pad such as a package and pressed a little. In order to cure the conductive adhesive, it is kept in a high temperature furnace for a predetermined time. In the high temperature state, the second support portion main body 16a and the package are both expanded and the adhesive is temporarily softened, so that no stress is generated in the supported portion (pad electrode) 29a. After the conductive adhesive is cured, when the second support body 16a and the package are cooled and the temperature returns to room temperature (25 ° C.), the conductive adhesive, the package, and the second support body 16a. Due to the difference between the linear expansion coefficients, the stress generated from the cured electroconductive adhesive is transmitted to the supported portion (pad electrode) 29a, and further, the first and third support portions 14 and 18 from the second support portion main body 16a. , Spread to the vibration region 12. In order to prevent the spread of stress, a stress relaxation slit 20 is provided.

The relationship between the formation site of the slit 20 and the distribution of stress (strain) generated in the piezoelectric substrate 10 is generally analyzed by simulation using a finite element method. As the stress in the vibration region 12 is reduced, a piezoelectric vibration element having excellent frequency temperature characteristics, frequency reproducibility, and frequency aging characteristics can be obtained.
Examples of the conductive adhesive include silicone-based, epoxy-based, polyimide-based, and bismaleimide-based. A polyimide-based conductive adhesive is used in consideration of frequency aging due to degassing of the piezoelectric vibration element 1. . Since the polyimide-based conductive adhesive is hard, the magnitude of the generated stress can be reduced by supporting the piezoelectric vibration element 1 at one place rather than at two places away from each other. A single support was used for the target piezoelectric vibrating element 1 for a 490 MHz band voltage controlled crystal oscillator (VCXO).
That is, a conductive adhesive is applied to the pad electrode 29a, placed on the element mounting pad of the package to be stored in an inverted manner, dried and fixed and connected, and the other pad electrode 29b is connected and connected using a bonding wire. Decided to connect. As shown in FIG. 1 (a), the pad electrode 29a and the pad electrode 29b are formed so as to face each other, so that they are supported at one place.

The piezoelectric substrate 10 shown in FIG. 1 is so-called X-long in which the length in the X-axis direction is longer than the length in the Z′-axis direction. As is well known, the frequency change when a force is applied to both ends in the X-axis direction of the AT-cut quartz substrate is compared with the frequency change when the same force is applied to both ends in the Z′-axis direction. When the force is applied to both ends in the Z′-axis direction, the frequency change is smaller. That is, it is preferable to provide the support point along the Z′-axis direction because the frequency change due to stress is reduced, and it is preferable as a piezoelectric vibration element.
In the embodiment shown in FIG. 1, the thin vibration region 12 is literally rectangular, but both corners corresponding to both ends of one side 12 c connected to the third support portion 16 of the thin vibration region 12. The corner may be chamfered.

In the embodiment of FIG. 1, the excitation electrodes 25 a and 25 b have a quadrilateral shape, that is, a square shape or a rectangular shape (the long side is the X-axis direction). The electrode need not be limited to this. In the embodiment shown in FIG. 3, the excitation electrode 25a on the front side in the figure is circular, and the excitation electrode 25b on the back side in the figure is a quadrangle sufficiently larger than the excitation electrode 25a. Note that the excitation electrode 25b on the back side may also be a sufficiently large circle.
In the embodiment shown in FIG. 4, the excitation electrode 25a on the front surface side in the drawing is elliptical, and the excitation electrode 25b on the back surface side in the drawing is a quadrangle having a sufficiently larger area than the excitation electrode 25a. The displacement distribution in the X-axis direction differs from the displacement in the Z′-axis direction due to the anisotropy of the elastic constant, and the cut surface obtained by cutting the displacement distribution along a plane parallel to the XZ ′ plane is elliptical. Therefore, the piezoelectric vibration element 1 can be driven most efficiently when the elliptical excitation electrode 25a is used. That is, the capacitance ratio γ (= C0 / C1, where C0 is the capacitance and C1 is the series resonance capacitance) of the piezoelectric vibration element 1 can be minimized.
The excitation electrode 25a may be oval.

FIG. 5 is a schematic diagram illustrating a configuration of the piezoelectric vibration element 2 according to the second embodiment. 5A is a plan view of the piezoelectric vibration element 2, FIG. 5B is a cross-sectional view of the PP cross section viewed from the + X-axis direction, and FIG. 5C is a cross-sectional view of the QQ cross-section of −Z. 'It is a sectional view seen from the axial direction.
The piezoelectric vibration element 2 is different from the piezoelectric vibration element 1 shown in FIG. 1 in the position where the stress relaxation slit 20 is provided. In the present embodiment, the slit 20 is formed in the second inclined portion 15 b that is separated from the one side 12 b of the thin vibration region 12. Rather than forming the slit 20 in the second inclined portion 15b so that one edge of the slit 20 is in contact with the side 12b along one side 12b of the vibration region 12, both ends of the second inclined portion 15b are formed. A slit 20 is provided apart from the edge. That is, in the second inclined portion 15b, an extremely fine strip 15b ′ connected to the edge of the one side 12b of the vibration region 12 is left. In other words, an extremely fine strip 15 b ′ is formed between the side 12 a and the slit 20.

  The reason for leaving the ultra-thin inclined portion 15b 'is as follows. That is, when the excitation electrodes 25a and 25b are formed in the vibration region 12 and a high frequency voltage is applied for excitation, the inharmonic mode (A0, S1, A1, S2,...) Is excited in addition to the main vibration (S0). It is desirable that only the main vibration (S0) mode be a confinement mode, and other inharmonic modes be a propagation mode (unconfinement mode). However, when the vibration region 12 becomes thin and the fundamental frequency becomes several hundred MHz, it is necessary to make the thickness of the excitation electrode equal to or larger than a predetermined thickness in order to avoid ohmic cross of the electrode film. For this reason, the plate back amount becomes large, and the inharmonic mode close to the main vibration becomes the energy confinement mode. In order to suppress the magnitude of the amplitude of the low-order inharmonic mode (proportional to the CI value), it is only necessary to prevent the condition that the standing wave of the inharmonic mode is established. That is, the shape of both end edges in the Z′-axis direction of the vibration region 12 in FIG. 5 is point-symmetric, and the shape of both end edges in the X-axis direction becomes asymmetrical by leaving the ultrathin strip 15b ′. The amplitude of the in-harmonic mode standing wave can be suppressed.

FIG. 6 is a schematic diagram illustrating a configuration of the piezoelectric vibration element 3 according to the third embodiment. 6A is a plan view of the piezoelectric vibration element 3, FIG. 6B is a cross-sectional view of the PP cross section viewed from the + X axis direction, and FIG. 6C is a cross-sectional view of the QQ cross-section of −Z. 'It is a sectional view seen from the axial direction.
The piezoelectric vibrating element 3 is different from the piezoelectric vibrating element 1 shown in FIG. 1 in that two stress relaxation slits are provided in parallel in the second support portion 15. That is, the first slit 20a is provided in the surface of the second support portion main body 15a, and the second slit 20b is formed in the surface of the second inclined portion 15b. Since the formation of individual slits in the surface of the second support portion main body 15a and in the surface of the second inclined portion 15b has already been described, the description thereof is omitted here.
As shown in the plan view of FIG. 6A, the first slit 20a and the second slit 20b are not simply juxtaposed in the X-axis direction as shown in the plan view of FIG. They may be arranged so as to be staggered in the Z′-axis direction. The piezoelectric vibration element 3 provided with the two slits 20a and 20b can enhance the effect of suppressing the stress caused by the conductive adhesive so as not to extend to the vibration region 12. The configuration of the modification shown in FIG. 7B is a piezoelectric vibration element that has the effect of the slit 20 shown in FIG. 1 and FIG. 6, respectively. The slit 20 includes the second inclined portion 15b. The second support main body 15a is straddled.

FIG. 8 is a manufacturing process flowchart relating to the formation of the recesses 11 and 11 ′ on both surfaces of the piezoelectric substrate 10 and the formation of the outer shape of the piezoelectric substrate 10 and the slit 20. Here, a quartz wafer is taken as an example of the piezoelectric wafer, and the cross-sectional view shows only the cross section. In step S1, a quartz wafer 10W having a predetermined thickness polished on both sides, for example, 80 μm, is sufficiently washed and dried, and then chromium (Cr) is ground on the front and back surfaces by sputtering or the like. A metal film (corrosion resistant film) M in which gold (Au) is laminated is formed.
In step S2, a photoresist film (referred to as a resist film) R is applied to both surfaces of the metal film M on the front and back surfaces. In step S3, the resist film R in a portion corresponding to the recessed portions on the front and back surfaces is exposed using an exposure apparatus and a mask pattern. When the exposed resist film R is developed and the exposed resist film is peeled off, the metal films M at positions corresponding to the recessed portions on the front and back surfaces are exposed. When the gold layer films M exposed from the respective resist films R are dissolved and removed using a solution such as aqua regia, the crystal planes at positions corresponding to the recessed portions on the front and back surfaces are exposed.

In step S4, the exposed quartz surface is etched from the front and back surfaces using a mixed liquid of hydrofluoric acid (hydrofluoric acid) and ammonium fluoride until a desired thickness is obtained. In step S5, the resist films R on both sides are peeled off using a predetermined solution, and the exposed metal films M on both sides are removed using aqua regia or the like. At this stage, the quartz wafer 10W is slightly shifted on both main surfaces to form the recessed portions 11 and 11 ′, and the quartz wafers 10W are regularly arranged in a lattice shape. In step S6, a metal film M (Cr + Au) is formed on both surfaces of the quartz wafer 10W obtained in step S5. In step S7, a resist film R is applied to both surfaces of the metal film M (Cr + Au) formed in step S6.
In step S8, each resist film R in a portion corresponding to the outer shape of the piezoelectric substrate 10 and a slit (not shown) is exposed from both the front and back surfaces using an exposure apparatus and a predetermined mask pattern, and developed to develop each resist. The film R is peeled off. Further, the exposed metal film M is removed by dissolving with a solution such as aqua regia.

In step S9, the exposed quartz surface is etched using a mixed liquid of hydrofluoric acid (hydrofluoric acid) and ammonium fluoride to form the outer shape of the piezoelectric substrate 10 and a slit (not shown). In step S10, the remaining resist film R is peeled off, and the exposed excess metal film M is dissolved and removed. At this stage, the crystal wafer 10W is in a state where the piezoelectric substrates 10 are connected by supporting strips and are regularly arranged in a lattice shape. As shown in step S10, the present invention is characterized in that concave portions 11 and 11 ′ are formed on both principal surfaces of the piezoelectric substrate to form a vibration region 12, and third and fourth connected to the vibration region 12 are provided. The support parts 16 and 17 are formed point-symmetrically with respect to the center of the piezoelectric substrate 10.
After step S10 is completed, the thickness of the vibration region 12 of each piezoelectric substrate 10 regularly arranged in a lattice pattern on the quartz wafer 10W is measured using, for example, an optical technique. When the measured thickness of each vibration region 12 is thicker than a predetermined thickness, the thickness is finely adjusted so as to fall within the predetermined thickness range.

  After adjusting the thickness of the vibration region 12 of each piezoelectric substrate 10 formed on the quartz wafer 10W within a predetermined thickness range, the excitation electrodes 25a and 25b and the lead electrodes 27a and 27b are provided on each piezoelectric substrate 10. The forming procedure will be described with reference to a manufacturing process flowchart shown in FIG. In step S11, a nickel (Ni) thin film is formed on the entire front and back surfaces of the quartz wafer 10W by sputtering or the like, and a gold (Au) thin film is stacked thereon to form a metal film M. Next, in step S12, a resist is applied on the metal film M to form a resist film R. In step S13, the resist film R in portions corresponding to the excitation electrodes 25a and 25b and the lead electrodes 27a and 27b is exposed using the mask pattern Mk. In step S14, the exposed resist film R is developed and the unnecessary resist film R is peeled off using a solution. Next, the metal film M exposed by peeling off the resist film R is dissolved and removed with a solution such as aqua regia. In step S15, when the unnecessary resist film R remaining on the metal film M is peeled off, excitation electrodes 25a and 25b, lead electrodes 27a and 27b, and the like are formed on each piezoelectric substrate 10. By dividing the half-etched support strip connected to the quartz wafer 10W, the divided piezoelectric vibration element 1 is obtained.

By the way, when the crystal is wet-etched, the etching proceeds along the Z-axis, but has an etching anisotropy peculiar to the crystal in which the etching rate changes according to the direction of each crystal axis. Therefore, the etching surface that appears due to the anisotropy of this etching appears to vary depending on the direction of each crystal axis. In many academic papers and prior patent literatures that have studied etching anisotropy so far, Has been discussed. Despite this background, there is no clearly organized data on crystal etching anisotropy. Nanofabrication technology will be required more and more in the future in order to manufacture small piezoelectric vibration elements. However, depending on the literature, there are many differences in the crystal planes that appear due to differences in etching conditions (type of etching solution, etching rate, etching temperature, etc.). It is.
Therefore, the present inventor conducted etching simulation, prototype experiment, nano-level surface analysis, and observation in manufacturing the piezoelectric vibration element according to the present invention by using the photolithography technique and the wet etching technique. Repeatedly, it has been found that the piezoelectric vibrator according to the present invention has the following modes, and will be described in detail below.

  FIGS. 10 and 11 are views for explaining the cross-sectional shapes of the recessed portions 11 and 11 ′ on both surfaces of the AT-cut quartz crystal wafer 10 </ b> W formed by etching. FIG. 10A is a plan view of the crystal wafer 10W in step S5 of FIG. At this stage, the recessed portions 11 and 11 ′ are regularly formed in a lattice shape on both the upper and lower surfaces of the crystal wafer 10 </ b> W. FIG. 10B is a cut surface (cut) in the X-axis direction, and each wall surface of the upper recess portion 11 and the lower recess portion 11 ′ is not a vertical wall surface but an inclined wall surface. That is, the wall surface in the −X axis direction of the upper recessed portion 11 forms the inclined wall surface X1, and the wall surface in the + X axis direction forms the inclined wall surface X2. Further, the wall surface in the −X axis direction of the lower recessed portion 11 ′ forms an inclined wall surface X <b> 2, and the wall surface in the + X axis direction forms an inclined wall surface X <b> 1. Each inclined wall surface is etched point-symmetrically with respect to the center of the vibration region 12. Thus, since the progress of etching has anisotropy in the crystal axis direction, the etching openings are generally arranged with a slight shift between the upper and lower surfaces.

FIGS. 10C to 10E are enlarged views of the wall surfaces X1 and X2 of the recessed portions 11 and 11 ′ and the wall surface X3 of the groove portion. The inclined wall surface X1 in the −X-axis direction of the upper recessed portion 11 is etched with an inclination of approximately 62 degrees with respect to the plane of the crystal wafer 10W, as shown in FIG. Further, the inclined wall surface X2 in the + X axis direction is perpendicular to the plane of the crystal wafer 10W (90 degrees), and the etching proceeds slightly, but thereafter, the etching proceeds with a gentle inclination. The wall surface in the −X-axis direction of the lower recessed portion 11 ′ becomes the inclined wall surface X2, and the wall surface in the −X-axis direction becomes the inclined wall surface X1. That is, the inclined wall surface of the upper recessed portion 11 and the inclined wall surface of the lower recessed portion 11 ′ are in point symmetry with respect to the center of the vibration region 12.
Both surfaces of the vibration region 12 formed by the bottom surface of the upper concave portion 11 and the bottom surface of the lower concave portion 11 ′ are etched in parallel with the original plane of the crystal wafer. That is, the vibration region 12 has a flat plate shape whose front and back surfaces are parallel.

FIG. 10D is a cross-sectional view showing the outer shape of the piezoelectric substrate 10 and the slit 20. The outer shape and the slit 20 are formed in the etching step of step S9 in FIG. 8, and the first support portion main body 14a and the first inclined portion 14b are formed at the end portion in the −X axis direction (left side in the drawing). A first support portion 14 is formed, and a second support portion 15 including a second support portion main body 15a and a second inclined portion 15b is formed at an end portion in the + X axis direction (left and right in the drawing). The A slit 20 is formed in the surface of the second support body 15a.
FIG. 10E is a cross-sectional view of the groove portion for breaking formed in the quartz wafer 10W, and is formed by the etching process in step S9 of FIG. The cross section of the groove formed perpendicular to the X axis has a wedge shape. This is because the wall surface X3 of the upper groove portion of the substrate 10 is formed of the wall surface X1 in the −X axis direction and the wall surface X2 in the + X axis direction, and thus has a wedge shape. The lower groove portion of the substrate 10 is formed point-symmetrically with the upper groove with respect to the center of the vibration region 12.
When an electrode is provided on the surface where the recessed portions 11 and 11 ′ are formed, it is necessary to pay attention to the vertical wall surface of the wall surface X2 formed in the + X axis direction. It is desirable to avoid the electrode film because it tends to tear.

  FIG. 11 is a view for explaining the wall surfaces of the front side and back side recessed portions 11, 11 ′ formed on the piezoelectric substrate 10, particularly in the sectional view in the Z′-axis direction. FIG. 11A is a plan view of the crystal wafer 10W in step S5 of FIG. FIG. 11B is a cut surface (cut) along the Z′-axis direction of the upper concave portion 11 and the lower concave portion 11 ′ of the crystal wafer 10 </ b> W. The wall surface in the −Z′-axis direction of the upper concave portion 11 forms an inclined wall surface Z1, and the wall surface in the + Z′-axis direction forms an inclined wall surface Z2. The lower concave portion 11 ′ is formed in a point-symmetric relationship with the upper concave portion 11 with respect to the center of the vibration region 12. That is, the wall surface in the −Z′-axis direction of the lower recessed portion 11 ′ forms the inclined wall surface Z 2, and the wall surface in the + Z′-axis direction forms the inclined wall surface Z 1.

FIGS. 11C to 11E are enlarged views of the wall surfaces Z1 and Z2 of the upper and lower recessed portions 11 and 11 ′ and the wall surface Z3 of the groove portion. The wall surface in the −Z′-axis direction of the upper recessed portion 11 is etched with a relatively gentle inclination with respect to the plane of the crystal wafer 10 </ b> W as shown in the left side of FIG. . The wall surface in the + Z′-axis direction exhibits an inclined wall surface Z2 as shown on the right side of FIG. 11C. That is, the etching is first performed with the steep inclined wall surface Z2a with respect to the plane of the quartz wafer 10W, but thereafter, the etching proceeds with the gentle inclined wall surface Z2b. The wall surface along the Z′-axis direction of the lower recessed portion 11 ′ has a point-symmetric relationship with the upper recessed portion 11 with respect to the center of the vibration region 12.
FIG. 11D is a cross-sectional view of the outer shape of the piezoelectric substrate 10 after the outer shape is processed. The outer shape is processed by etching from the two broken lines Zc1 and Zc2 in FIG. The outer shape is formed in the etching step of step S9 in FIG. 8, and the third support portion is formed of the third support portion main body 16a and the third inclined portion 16b at the end in the −Z ′ axis direction (left side in the drawing). 16 is formed, and a fourth support portion 17 including a fourth support portion main body 17a and a fourth inclined portion 17b is formed at an end portion in the + Z ′ axis direction (left and right in the drawing). The third support part 16 and the fourth support part 17 are formed substantially point-symmetrically with respect to the center of the vibration region 12.

FIG. 11E is a cross-sectional view of the upper and lower grooves formed orthogonal to the Z′-axis direction, and both present a wedge-shaped cross section Z3. The upper and lower grooves are grooves for folding the crystal wafer 10W. The wall surface Z3 of the upper groove portion is formed by the wall surface Z1 in the −Z′-axis direction of the upper recessed portion 11 and the wall surface Z2 (the wall surface Z2a and the wall surface Z2b) in the + Z′-axis direction. Presents. The wall surface Z3 of the lower groove portion is formed substantially symmetrically with respect to the wall surface and the center of the upper groove portion.
If the groove for folding is formed in the X-axis direction and the Z′-axis direction, the cross-sectional shape becomes a wedge shape, and the folding is easy.
A feature of the present invention is that etching is advanced from both main surfaces of the piezoelectric substrate 10 and concave portions 11 and 11 ′ that face both the main surfaces are formed to form a vibration region 12. The processing time required for etching is reduced. It became possible to halve. In addition, as shown in FIG. 11D, one of the features is that the piezoelectric substrate can be miniaturized by removing both the outer sides of the two broken lines indicated by Zc1 and Zc2 by etching. Since etching proceeds from both main surfaces of the piezoelectric substrate 10, the depth dug by etching from the respective main surfaces of the piezoelectric substrate 10 can be reduced, so that regions in which individual pieces in the wafer are laid out at the time of manufacture It was possible to reduce the variation in thickness of the vibrating portion that was thin between the wafers or between the wafers. The reason for this is that if the piezoelectric substrate 10 is immersed in the etching solution for a long time, the concentration of the solution in the etching solution may be different, and the etching of the piezoelectric substrate 10 is caused by the concentration difference. There is a possibility that the uniformity of the vibration may not be maintained, and the thickness of the vibrating part may vary between regions where the individual pieces in the wafer are laid out or between wafers, making it difficult to control the thickness. Because there is.

Further, as shown in FIGS. 11C and 11D, a manufacturing method was established on the premise that both end portions in the drawing which are unnecessary as a vibration region are deleted. Compared to the structure with the conventional thick portion described as the prior art, the size of the piezoelectric vibration element 1 can be reduced while ensuring the area of the flat ultrathin portion that becomes the vibration region. .
Further, as described above, the frequency change when the force is applied to both ends in the X-axis direction of the AT-cut quartz substrate (the stress / strain caused by the mounting is described as the force), and the Z′-axis By comparing the frequency change when the same force is applied to both ends in the direction, the amount of frequency change when the force is applied to both ends in the Z′-axis direction can be reduced. Since the length in the direction is so-called X-long, which is longer than the length in the Z′-axis direction, a large area of the vibration part can be secured in the X-axis direction.
Moreover, since the thick support part is provided in at least one of the front and back with respect to the main surface of a vibration part over the perimeter of the vibration part of the piezoelectric vibration element 1 which concerns on this invention, vibration Since the end of the portion is not exposed to the outside, something is necessary for the piezoelectric vibration element 1 during the manufacture of the piezoelectric vibration element 1 or the process of mounting the piezoelectric vibration element 1 on a container and manufacturing the piezoelectric vibrator Also, from the viewpoint of reliability such as impact resistance of the piezoelectric vibration element 1 due to being hit or the like, the strength is maintained high, so that the reliability can be maintained high.
As a result, the displacement distribution of the thickness-shear vibration mode excited in the vibration region can be designed taking into account that the elliptical shape has a major axis in the X-axis direction due to the anisotropy of the elastic constant, The long axis to short axis ratio is 1.26: 1, and the design can be sufficiently made to be in the range of about 1.14 to 1.39: 1 in consideration of variations in manufacturing dimensions.

12 is a detailed view of the piezoelectric vibration element 1 shown in FIG. 1, FIG. 12 (a) is a perspective view, and FIG. 12 (b) is a cut surface of the QQ section in FIG. 1 (a). is there. As shown in FIG. 12B, in the outer shape of the piezoelectric vibration element 1, an inclined surface appears on the end surface intersecting the X axis, an inclined surface 1 appears on the end surface on the −X axis side, and an end surface on the + X axis side An inclined surface 2 appears. It was found that the cross-sectional shapes parallel to the XY ′ plane of the inclined surface 1 and the inclined surface 2 are different.
Further, in the vicinity where both the inclined surfaces 1 and 2 intersect with the main surface of the piezoelectric substrate, a vertical wall surface of the wall surface X2 formed in the + X-axis direction as shown in FIGS. 10B and 10E appears. Absent. The reason for this is that the time required for forming the inclined surface 1 and the inclined surface 2 is etched from the front and back surfaces of the piezoelectric substrate (quartz substrate) until it penetrates, compared to the etching time required to form the recess 11. Therefore, since the etching time is sufficiently long, the vertical wall surface does not appear due to the overetching action.
The inclined surfaces a1 and a2 constituting the inclined surface 1 are substantially symmetrical with respect to the X axis, and in the inclined surfaces b1, b2, b3 and b4 constituting the inclined surface 2, b1 and b4, b2 and b3 are , Each of which is found to be substantially symmetrical with respect to the X axis. Furthermore, it has been found that the inclination angle α of the inclined surfaces a1 and a2 with respect to the X axis and the inclination angle β of the inclined surfaces b1 and b4 with respect to the X axis have a relationship of β <α.

  A piezoelectric vibration element 4 of the embodiment shown in FIG. 13 is a modification of the piezoelectric vibration element 1 shown in FIG. 1, and the thickness of a part 15a ′ near the outer end of the second support part body 15a is set. The structure is thinned by etching or the like. The reason for this is that when the pad electrode 29b formed on the second support body 15a ′ and the external electrode terminal are connected by the bonding wire BW, the apex portion of the bonding wire does not contact the cover member to be covered. Because.

As shown in the embodiment examples of FIGS. 1, 5, 6, and 7, the high-frequency piezoelectric vibration element is miniaturized and the vibration region is strongly supported, and the piezoelectric vibration element is strong against vibration, impact, and the like. Is effective. Furthermore, by providing a slit, it is possible to suppress the spread of stress due to adhesion / fixing, so that the frequency temperature characteristic, the CI temperature characteristic, and the frequency aging characteristic are excellent, and the CI value of the main vibration is small. There is an effect that a piezoelectric vibration element having a large ratio of the CI value of adjacent spurious to the CI value of vibration, that is, a large CI value ratio can be obtained.
Moreover, when the site | part which supports the piezoelectric vibration element 1 becomes one point, it is possible to make small the stress which originates in a conductive adhesive.
As shown in the embodiment example of FIG. 6, by providing two slits in the second support portion, it is possible to better suppress the spread of stress that occurs when the piezoelectric vibration element is bonded and fixed. There is an effect that a piezoelectric vibration element can be obtained which is excellent in frequency reproducibility, frequency temperature characteristics, CI temperature characteristics, and frequency aging characteristics.
Also, as shown in FIGS. 1, 5, and 6, by providing a protruding portion at the end in contact with the vibration region, there is an effect that the impact resistance and vibration resistance of the piezoelectric vibration element are enhanced.

By forming a piezoelectric substrate rotated around the X axis, it is possible to configure the required specifications with a more suitable cut angle and frequency, and to have a frequency temperature characteristic according to the specifications, and a high-frequency fundamental piezoelectric vibration element Is effective.
In addition, by using a quartz AT-cut quartz substrate as a piezoelectric substrate, many years of experience and experience regarding photolithography technology and etching techniques can be utilized, so that not only mass production of piezoelectric substrates is possible, but also high-precision piezoelectric substrates As a result, the yield of the piezoelectric vibration element is greatly improved.
In addition, as shown in FIG. 1, the second support portion 15 has a second inclined portion 15b that increases in thickness as it moves away from one end edge connected to the vibration portion toward the other end edge, If the second support body 15a connected to the other edge of the second inclined portion 15 is provided, the piezoelectric vibration element having a high frequency and a fundamental wave can be downsized, and the vibration portion This is advantageous in that a piezoelectric vibration element that is strong in support of vibrations and shocks can be obtained.

FIGS. 14A and 14B are diagrams showing the configuration of the piezoelectric vibrator 5 according to the embodiment of the present invention. FIG. 14A is a longitudinal sectional view, and FIG. 14B is a plan view excluding a lid member. . The piezoelectric vibrator 5 includes, for example, the above-described piezoelectric vibration element 1 and a package that accommodates the piezoelectric vibration element 1. The package includes a package main body 40 formed in a rectangular box shape and a lid member 49 made of metal, ceramic, glass, or the like.
As shown in FIG. 14, the package body 40 is formed by laminating a first substrate 41, a second substrate 42, and a third substrate 43, and an aluminum oxide ceramic as an insulating material. -Green sheet is formed into a box shape and then sintered. A plurality of mounting terminals 45 are formed on the outer bottom surface of the first substrate 41. The third substrate 43 is an annular body from which the central portion is removed, and a metal seal ring 44 such as Kovar is formed on the upper peripheral edge of the third substrate 43.

The third substrate 43 and the second substrate 42 form a recess (cavity) that accommodates the piezoelectric vibration element 1. A plurality of element mounting pads 47 that are electrically connected to the mounting terminals 45 by conductors 46 are provided at predetermined positions on the upper surface of the second substrate 42. The position of the element mounting pad 47 is arranged so as to correspond to the pad electrode 29a formed on the second support body 14a when the piezoelectric vibration element 1 is placed.
When fixing the piezoelectric vibrator 5, first, the conductive adhesive 30 is applied to the pad electrode 29 a of the piezoelectric vibration element 1, and this is reversed and placed on the element mounting pad 47 of the package body 40 to apply a load. Call. As a characteristic of the conductive adhesive 30, the magnitude of stress (strain) caused by the adhesive 30 increases in the order of a silicone-based adhesive, an epoxy-based adhesive, and a polyimide-based adhesive. Further, degassing increases in the order of polyimide adhesive, epoxy adhesive, and silicone adhesive. As the conductive adhesive 30, it was decided to use a polyimide adhesive with little degassing in consideration of the secular change.

In order to cure the conductive adhesive 30 of the piezoelectric vibrator 1 mounted on the package body 40, it is placed in a high temperature furnace at a predetermined temperature for a predetermined time. After the conductive adhesive 30 is cured, the pad electrode 29b on the surface side and the electrode terminal 48 of the package body 40 are electrically connected by the bonding wire BW. As shown in FIG. 14B, since the portion for supporting and fixing the piezoelectric vibration element 1 to the package body 40 is one place, the magnitude of the stress generated by the support and fixing can be reduced.
After the annealing treatment, the frequency is adjusted by adding mass to the excitation electrodes 25a and 25b or reducing the mass. A lid member 49 is placed on the seal ring 44 formed on the upper surface of the package body 40, and the lid member 49 is seam welded in a vacuum or nitrogen N2 gas to be sealed. Alternatively, there is also a method in which the lid member 49 is placed on the low melting point glass applied to the upper surface of the package body 40 and melted and adhered. The cavity of the package is evacuated or filled with an inert gas such as nitrogen N 2 gas to complete the piezoelectric vibrator 5.
The pad electrode 29b and the electrode terminal 48 of the package are electrically connected using a bonding wire. Thus, when the site | part which supports the piezoelectric vibration element 1 becomes one point, it is possible to make small the stress resulting from a conductive adhesive.

  The piezoelectric vibration element 1 shown in FIG. 1 is formed with pad electrodes 29a and 29b adjacent to the upper and lower surfaces of the piezoelectric substrate 10, respectively. When the piezoelectric vibration element 1 is accommodated in the package, the piezoelectric vibration element 1 is turned over, and the pad electrode 29a and the terminal electrode of the package are fixed and connected with a conductive adhesive. The pad electrode 29b on the front surface side and the electrode terminal of the package are connected by a bonding wire BW. Thus, when the site | part which supports the piezoelectric vibration element 1 becomes one point, it is possible to make small the stress resulting from a conductive adhesive. Further, when the piezoelectric vibrating element 1 is turned upside down and accommodated in a package, and the larger excitation electrode 25b is placed on the upper surface, fine tuning of the frequency of the piezoelectric vibrating element 1 is facilitated.

FIGS. 15A and 15B are diagrams showing a configuration of a piezoelectric vibrator 5 according to another embodiment. FIG. 15A is a longitudinal sectional view, and FIG. 15B is a plan view excluding a lid member. As shown in the plan view of FIG. 15B, the pad electrodes 29a and 29b are spaced apart and arranged on the same plane. A difference from the embodiment shown in FIG. 14 is a method of supporting the piezoelectric vibrator 1. In the embodiment example of FIG. 14, support is provided at one place, whereas in the embodiment example of FIG. 15, the conductive adhesive is provided at two places (two points) of the second support portion 15 on one surface of the piezoelectric vibration element 1. It is the structure which applied, and intended to conduct, support and fix. Although the structure is suitable for reducing the height, the stress caused by the conductive adhesive may be slightly increased. Therefore, it can be expected that the influence of the stress on the vibration region can be suppressed by employing a piezoelectric vibration element provided with two slits as shown in FIGS. 6 and 7 as the third embodiment. Alternatively, when the hardness of the conductive adhesive is relatively hard, by reducing the distance between the centers of “two places (two points)” where the conductive adhesive is applied, the distortion caused by the mounting between the two points. There is also a technique for reducing (stress). On the other hand, by using a silicone-based adhesive whose conductive adhesive is relatively soft, the conductive adhesive is buffered and the distortion (stress) associated with the mounting between the two points is reduced. There is also a technique.
In the above-described embodiment of the piezoelectric vibrator 5, an example in which a laminated plate is used for the package body 40 has been described. However, a single-layer ceramic plate is used for the package body 40, and a cap that is drawn on the lid is used. A piezoelectric vibrator may be configured.

As shown in the embodiment of FIG. 14, when the high-frequency piezoelectric vibrator 1 is downsized and the portion supporting the piezoelectric vibrating element 1 becomes a single point, the stress caused by the conductive adhesive is reduced. be able to. As a result, there is an effect that a piezoelectric vibrator excellent in frequency reproducibility, frequency temperature characteristics, CI temperature characteristics, and frequency aging characteristics can be obtained. Furthermore, the CI value of the main vibration is reduced, and the ratio of the spurious CI value to the CI value of the main vibration, that is, a piezoelectric vibration element having a large CI value ratio is obtained, and the piezoelectric vibrator 5 having a small capacitance ratio γ is obtained. There is an effect that it is.
Further, as shown in the embodiment of FIG. 15, by configuring the two-point supported piezoelectric vibrator, there is an effect that the piezoelectric vibrator 5 having a reduced height can be obtained. By providing two slits, it is possible to suppress the influence of the supporting stress caused by the two-point support on the vibration part.

  FIG. 16 is a longitudinal sectional view showing an embodiment of the piezoelectric device 6 according to the present invention. The electronic device 6 is one of the piezoelectric vibration element 1 of the present invention (an example of the piezoelectric vibration element 1 is shown in FIG. 16 but may be another piezoelectric vibration element of the present invention) and an electronic component. Thermistor Th, which is a temperature sensing element as a temperature sensor, and a package that accommodates the piezoelectric vibration element 1 and the thermistor Th are schematically provided. The package includes a package main body 40 a and a lid member 49. The package body 40a has a cavity 31 for accommodating the piezoelectric vibration element 1 on the upper surface side, and a recess 32 for accommodating the thermistor Th on the outer back surface side. A plurality of element mounting pads 47 are provided at the end of the inner bottom surface of the cavity 31, and each element mounting pad 47 is electrically connected to the plurality of mounting terminals 45 by an internal conductor 46. The conductive adhesive 30 is applied to the pad electrode 29 a of the piezoelectric vibration element 1, and this is reversed and placed on the element mounting pad 47. A seal ring ring 44 made of Kovar or the like is baked on the upper portion of the package body 40a. A lid member 49 is placed on the seal ring ring 44 and welded using a resistance welding machine or the like, and the cavity 31 is sealed. Seal tightly. The cavity 31 may be evacuated or filled with an inert gas.

In the above embodiment example, the concave portion 32 is formed on the outer lower surface side of the package body 40a and the electronic component is mounted. However, the concave portion 32 is formed on the inner bottom surface of the package body 40a and the electronic component is mounted. May be.
Moreover, although the example which accommodated the piezoelectric vibration element 1 and the thermistor Th in the package 40a was demonstrated, as an electronic component accommodated in the package 40a, at least one of a thermistor, a capacitor | condenser, a reactance element, and a semiconductor element is accommodated. It is desirable to construct an electronic device.

The embodiment shown in FIG. 16 is an example in which the piezoelectric vibration element 1 and the thermistor Th are accommodated in a package 40a. With this configuration, since the thermistor Th of the temperature sensitive element is positioned very close to the piezoelectric vibration element 1, there is an effect that a temperature change of the piezoelectric vibration element 1 can be quickly detected. Moreover, since an electronic device is comprised with the piezoelectric vibration element of this invention and said electronic component, since a high frequency and a small electronic device can be comprised, there exists an effect that it can utilize for various uses.
In addition, when an electronic device (piezoelectric device) is configured using any one of a variable capacitance element, thermistor, inductor, and capacitor as an electronic component, an electronic device suitable for the required specifications can be realized in a small size and at low cost. effective.

FIG. 17 is a view showing a configuration of a piezoelectric oscillator 7 which is a kind of electronic device according to an embodiment of the present invention, where FIG. 17 (a) is a longitudinal sectional view and FIG. 17 (b) is a lid member. FIG. The piezoelectric oscillator 7 includes a package main body 40b, a lid member 49, the piezoelectric vibration element 1, an IC component 51 on which an oscillation circuit for exciting the piezoelectric vibration element 1 is mounted, a variable capacitance element whose capacitance changes with voltage, and temperature. And at least one of electronic components 52 such as a thermistor and an inductor whose resistance changes.
A conductive adhesive (polyimide) 30 is applied to the pad electrode 29 a of the piezoelectric vibration element 1, and this is reversed and placed on the element mounting pad 47 of the package body 40 b, and the pad electrode 29 a and the element mounting pad 47 are connected. Ensuring continuity. The pad electrode 29b on the upper surface side and the other electrode terminal 48 of the package body 40b are connected by a bonding wire, and electrical connection with one electrode terminal 55 of the IC component 51 is achieved. The IC component 51 is fixed at a predetermined position on the package body 40b, and the terminal of the IC component 51 and the electrode terminal 55 of the package body 40b are connected by the bonding wire BW. In addition, the electronic component 52 is placed at a predetermined position on the package body 40b and connected using metal bumps or the like. The package body 40b is filled with an inert gas such as vacuum or nitrogen, and the package body 40b is sealed with a lid member 49 to complete the piezoelectric oscillator 7.
In the method of connecting the pad electrode 29a and the electrode terminal of the package with the bonding wire BW, the site supporting the piezoelectric vibration element 1 becomes one point, and the stress caused by the conductive adhesive can be reduced. . In addition, since the piezoelectric vibrating element 1 is turned upside down and the larger excitation electrode 25b is placed on the upper surface when housed in the package, fine tuning of the frequency of the electronic device (piezoelectric oscillator) 7 is facilitated.

In the piezoelectric oscillator 7 shown in the embodiment of FIG. 17, the piezoelectric vibration element 1, the IC component 51, and the electronic component are arranged on the same piezoelectric substrate. However, the piezoelectric oscillator 7 of the embodiment shown in FIG. Using the package main body 60, the piezoelectric vibration element 1 is accommodated in the cavity 31 formed in the upper part, the inside of the cavity is filled with vacuum or nitrogen N 2 gas, and sealed with the lid member 61. In the lower part, an IC component 51 on which an oscillation circuit, an amplification circuit, etc. for exciting the piezoelectric vibration element 1 are mounted, a variable capacitance element, and an electronic component 52 such as an inductor, thermistor, capacitor, etc., as needed, are provided with metal bumps (Au Conductive and connected to the terminal 67 of the package body 60 via the bumps 68.
The electronic device (piezoelectric oscillator) 7 according to the present invention separates the piezoelectric vibration element 1 from the IC component 51 and the electronic component 52 and hermetically seals the piezoelectric vibration element 1 alone. Excellent frequency aging.

As shown in FIGS. 17 and 18, by configuring a piezoelectric device (for example, a voltage-controlled piezoelectric oscillator), the frequency reproducibility, frequency temperature characteristics, and aging characteristics are excellent, and the voltage is small and has a high frequency (for example, 490 MHz band). There is an effect that a control type piezoelectric oscillator can be obtained. Further, since the piezoelectric device uses the fundamental wave piezoelectric vibration element 1, the capacitance ratio is small, and since the fundamental wave piezoelectric vibration element is used, the frequency variable width is wide and the voltage control type piezoelectric element has a good S / N ratio. There is an effect that an oscillator can be obtained.
In addition, piezoelectric devices such as piezoelectric oscillators, temperature compensated piezoelectric oscillators, and voltage controlled piezoelectric oscillators can be configured as piezoelectric devices. Piezoelectric oscillators with excellent frequency reproducibility and aging characteristics, temperature compensation with excellent frequency temperature characteristics The piezoelectric oscillator has an effect that it is possible to obtain a voltage-controlled piezoelectric oscillator having a stable frequency, a wide variable range, and a good S / N ratio (signal to noise ratio).

FIG. 19 is a schematic configuration diagram showing a configuration of an electronic apparatus according to the present invention. The electronic device 8 includes the piezoelectric vibrator 5 described above. Examples of the electronic device 8 using the piezoelectric vibrator 5 include a transmission device. In these electronic devices 8, the piezoelectric vibrator 6 is used as a reference signal source, a voltage variable piezoelectric oscillator (VCXO), or the like, and can provide a small-sized electronic device having good characteristics.
As shown in the schematic diagram of FIG. 19, by using the piezoelectric vibrator of the present invention for an electronic device, an electronic device having a reference frequency source having a high frequency and excellent frequency stability and a good S / N ratio can be configured. There is an effect.

[Modified Embodiment]
As a technique for further reducing and suppressing the stress caused by mounting the piezoelectric vibration element, the following structure can be adopted.
The piezoelectric substrate 10 in the embodiment of FIG. 20A is a piezoelectric substrate 10 provided with a thin part having a vibration region 12 and a thick part provided at the periphery of the thin part and thicker than the thin part. In the piezoelectric substrate, the mount portion F is connected to the thick support portion 13 side by side through the buffer portion S in the direction of the edge, and the buffer portion S is interposed between the mount portion and the thick support portion. It has a slit 20, and the mount part F has chamfered parts 21 at both ends in a direction orthogonal to the direction in which the mount part F, the buffer part S, and the thick support part 13 are arranged. To do.
The piezoelectric substrate 10 of FIG. 20B is a piezoelectric substrate 10 including a thin portion having a vibration region 12 and a thick support portion 13 provided at the periphery of the thin portion and thicker than the thin portion. Mount portions F are connected to the meat support portion 13 side by side through the buffer portion S, and the buffer portion S has a slit 20 between the mount portion F and the thick wall support portion 13. The mounting portion F, the buffer portion S, and the thick support portion 13 have notches 22 at both ends in the direction orthogonal to the direction in which the mounting portion F, the buffer portion S, and the thick support portion 13 are arranged. The width in the orthogonal direction is narrower than the width in the longitudinal direction of the slit, and both end portions in the longitudinal direction of the slit are closer to the outer periphery in the orthogonal direction of the buffer portion S than both end portions of the mount portion F.
The piezoelectric substrate 10 in FIG. 20C is a piezoelectric substrate 10 including a thin portion having a vibration region 12 and a thick support portion 13 provided on the periphery of the thin portion. The buffer portion S and the mount portion F are sequentially connected, and the buffer portion S has a slit 20 between the mount portion F and the thick wall support portion 13, and the mount portion F includes the mount portion F and the buffer portion S. And the thick-walled support portion 13 are characterized by having cutout portions 22 at both ends in a direction perpendicular to the direction in which the thick support portions 13 are arranged.

FIG. 21 is characterized in that it takes the form of two-point support, that is, the mount portion F1 and the mount portion F2, with respect to the structure of FIG.
In FIGS. 20 and 21, inclined portions are illustrated on the inner walls of the support portions 14, 15, and 16 of the thick support portion 13, while the outer side wall surface of the thick support portion 13 is also illustrated on the inner wall surface of the thick support portion 13. Although the inclined surfaces as shown in FIG. 12 are not shown, these inclined portions and inclined surfaces are formed at corresponding portions as shown in FIG.
In addition, each code | symbol in FIG. 20, FIG. 21 respond | corresponds with the site | part which the same code | symbol of said each embodiment shows.

[Modified Example 2]
22A is a plan view of the piezoelectric vibration element 1, and FIG. 22B is an enlarged plan view of the embodiment of the pad electrode 29a (mount portion F) of the piezoelectric vibration element 1, and FIG. FIG. 3C shows a cross-sectional view of the mount portion F. In this mount part F, the area is gained by making it uneven in order to improve the adhesive strength.

1, 2, 3, 4... Piezoelectric vibrating element 5, 5. Piezoelectric vibrator, 6, 7 ... Piezoelectric device, 8 ... Electronic equipment, 10 ... Piezoelectric substrate, 10W ... Quartz wafer, 11, 11 '... Recessed portion, 12 ... Vibration region, 12a, 12b, 12c, 12d ... one side of vibration region, 13 ... support portion, 14 ... first support portion, 14a ... first support portion main body, 14b ... first inclined portion, 15 ... second 15a ... second support part main body, 15b ... second inclined part, 15b '... extra fine piece, 16 ... third support part, 16a ... third support part main body, 16b ... third inclination 17, fourth support portion, 17 a, fourth support portion main body, 17 b, fourth inclined portion, 20, slit, 20 a, first slit, 20 b, second slit, 21, chamfered portion, 22 ... Notch, 25a, 25b ... Excitation electrode, 27a, 27b ... Lead electrode, 29a 29b ... Pad electrode, 30 ... Conductive adhesive, 31 ... Cavity, 32 ... Recess, 33 ... Electronic component mounting pad, 40, 40a, 40b ... Package body, 41 ... First substrate, 42 ... Second substrate , 43 ... Third substrate, 44 ... Seal ring, 45 ... Mounting terminal, 46 ... Conductor, 47 ... Element mounting pad, 48 ... Electrode terminal, 49 ... Lid member, 51 ... IC component, 52 Electronic component, 55 ... Electrode Terminal, 60 ... Package body, 61 ... Cover member, 65 ... Mounting terminal, 66 ... Conductor, 67 ... Part terminal, 68 ... Metal bump (Au bump), Th ... Thermistor, F, F1, F2 ... Mount, S ... Buffer part

Claims (14)

A vibration part including a vibration region;
A support unit that is integrated with the vibration unit and is thicker than the thickness of the vibration unit;
A piezoelectric substrate having
A pair of excitation electrodes arranged to face the vibration region on the front and back sides;
A piezoelectric vibration element having
The support part is
A first support portion and a second support portion, which are respectively provided so as to sandwich the vibration portion along two opposing sides of the main surface of the vibration portion;
A third support part continuously connecting one end of each of the first and second support parts;
A fourth support part connecting the other end of each of the first and second support parts;
With
The main surfaces of the front and back surfaces of the first and second support portions are protruded from the main surfaces of the front and back surfaces of the vibration portion,
One main surface of the third support part protrudes from one main surface of the vibration part,
The other main surface of the third support portion and the other main surface of the vibration portion are the same surface,
One main surface of the fourth support part protrudes from the other main surface of the vibration part,
The piezoelectric vibration element, wherein the other main surface of the fourth support portion and the one main surface of the vibration portion are the same surface. The piezoelectric substrate is
Centering on the X axis of the orthogonal coordinate system consisting of the X axis as the electrical axis that is the crystal axis of the crystal, the Y axis as the mechanical axis, and the Z axis as the optical axis,
An axis obtained by inclining the Z axis by a predetermined angle in the −Y direction of the Y axis is a Z ′ axis,
An axis obtained by inclining the Y axis by the predetermined angle in the + Z direction of the Z axis is a Y ′ axis,
It is composed of a plane parallel to the X axis and the Z ′ axis,
The piezoelectric vibration element according to claim 1, wherein the piezoelectric vibration element is a quartz substrate having a thickness in a direction parallel to the Y ′ axis. The projecting portion of the third support portion is on the plus side of the Z ′ axis;
The piezoelectric vibration element according to claim 2, wherein the projecting portion of the fourth support portion is on the negative side of the Z ′ axis. The second support part is
A second inclined portion whose thickness increases as the distance from the one edge connected to the vibrating portion increases toward the other edge;
A second support portion main body provided continuously with the other edge of the second inclined portion;
The piezoelectric vibration element according to claim 1, wherein the piezoelectric vibration element is provided. In the second support part,
The piezoelectric vibration element according to claim 4, wherein at least one slit is provided. The slit is
The piezoelectric vibration element according to claim 5, wherein the piezoelectric vibration element is disposed in the second support portion main body along a boundary portion between the second inclined portion and the second support portion main body. The slit is
The piezoelectric vibration element according to claim 5, wherein the piezoelectric vibration element is disposed in the second inclined portion so as to be separated from one side of the vibration region. The slit is
A first slit disposed in the second support body;
A second slit disposed in the second inclined portion and spaced from one side of the vibration region;
The piezoelectric vibration element according to claim 5, comprising: The first slit is
The piezoelectric vibration element according to claim 8, wherein the piezoelectric vibration element is disposed in the second support portion main body along a boundary portion between the second inclined portion and the second support portion main body. The piezoelectric vibration element according to any one of claims 1 to 9,
A package containing the piezoelectric vibration element;
A piezoelectric vibrator characterized by comprising: The piezoelectric vibration element according to any one of claims 1 to 9,
Electronic components,
An electronic device characterized by comprising a package. The electronic component is
The electronic device according to claim 11, wherein the electronic device is any one of a variable capacitance element, a thermistor, an inductor, and a capacitor.   The electronic device according to claim 11, wherein an oscillation circuit for exciting the piezoelectric vibration element is provided in the package.   An electronic apparatus comprising the piezoelectric vibrator according to claim 10.

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