JP2013258452A - Vibration element, vibrator, electronic device, electronic apparatus, mobile body, and manufacturing method of vibration element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a small high frequency piezoelectric vibration element, which has a small CI value and suppresses a spurious emission in a surrounding area, with a fundamental wave.SOLUTION: A piezoelectric vibration element 1 includes: a rectangular vibration part 12; a piezoelectric substrate 10 including a thick part 13; excitation electrodes 25a, 25b; and lead electrodes 27a, 27b. The thick part 13 includes: a fourth thick part 14; a third thick part 15; a first thick part 16; and a second thick part. The third thick part 15 includes: a third inclination part 15b; and a third thickness part body 15a. At least one slit 20 is provided at the third thick part 15.

Description

  The present invention relates to a vibrator that excites a thickness shear vibration mode, and in particular, a vibration element having a so-called inverted mesa structure, a vibrator, an electronic device, an electronic device using the vibrator, a moving body using the vibrator, and a vibration The present invention relates to a method for manufacturing an element.

An AT-cut quartz crystal resonator, which is an example of a resonator, exhibits a cubic curve that excels in frequency and temperature characteristics and is suitable for miniaturization and higher frequency, and the vibration mode of the main vibration to be excited is thickness shear vibration. It is used in various fields such as oscillators and electronic devices.
In recent years, it has been desired to further increase the frequency of the AT cut crystal resonator, and accordingly, it has become necessary to further reduce the thickness of the vibration part of the resonator element used in the AT cut crystal resonator. However, when the vibration part is thinned, the strength of the vibration part is weakened, and there is a possibility that the impact resistance and the like are deteriorated.
In order to cope with this, for example, as shown in Patent Document 1, a so-called reverse is achieved by forming concave portions (vibrating portions) so as to be opposed to each other on both the front and back surfaces of the quartz substrate. An AT-cut vibrator having a mesa structure is disclosed. More specifically, a third thick part is provided in the X-axis direction of the vibration part, and extends from both ends of the third thick part along the outer side in the Z-axis direction so as to sandwich the vibration part. It is the structure by which the 1st thick part to perform and the 2nd thick part are provided. An X long substrate is used as the quartz substrate, and an excitation electrode is provided in a region where the flatness of the vibrating portion formed in the recessed portion is ensured.

JP 2003-264446 A

  However, although the etching process is generally used for forming the AT-cut vibrator having the inverted mesa structure as described above, the first thick part and the second thick part provided in the Z-axis direction. Etching residue (also referred to as “fins”) is generated at the boundary between and the vibrating portion. Due to this etching residue, the effective area of the vibration part is reduced, and 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 of the spurious. It has been found that there is a problem that the value cannot satisfy the requirement in terms of the value.

  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 vibration element according to this application example is provided integrally with the vibration unit along the first outer edge of the vibration unit and the vibration unit, and the first thickness is thicker than the vibration unit. A meat part and a second thick part provided integrally with the vibration part along the second outer edge of the vibration part facing the first outer edge and having a thickness greater than the vibration part. The first thick portion is provided so as to protrude from one main surface of the vibrating portion, and the second thick portion is a main surface on the back side of the one main surface of the vibrating portion. It is characterized by being provided so as to protrude.

  According to the vibration element having this configuration, the first thick portion is provided to protrude from one main surface of the vibration portion, and the second thick portion is provided to protrude from the main surface on the back side of the vibration portion. It has been. Therefore, it is possible to select the main surface on the side where no etching residue is generated and to provide the first thick portion and the second thick portion, and to increase the effective area of the vibration portion. As a result, the CI value of the main vibration, the adjacent spurious CI value ratio (= CIs / CIm, where CIm is the CI value of the main vibration, CIs is the CI value of the spurious, and an example of the standard is 1.8 or more) There is an effect of improving. Furthermore, since the first thick part and the second thick part are provided, the support of the vibration part is strengthened, and there is an effect that a vibration element that is strong against vibration, impact, and the like is obtained.

  Application Example 2 In the vibration element according to the application example described above, along the third outer edge of the vibration unit that connects one end of each of the first outer edge and the second outer edge, A third thick part thicker than the vibration part is provided integrally with the vibration part.

  According to this configuration, since the first thick part to the third thick part are provided along the three outer edges of the vibration part, the support of the vibration part is further strengthened, and vibration, impact, etc. There is an effect that a strong vibration element can be obtained.

  Application Example 3 In the vibration element according to the application example described above, along the fourth outer edge of the vibration unit that connects between the other ends of the first outer edge and the second outer edge, A fourth thick part having a thickness larger than that of the vibration part is provided integrally with the vibration part.

  According to this configuration, since the first thick portion to the fourth thick portion are provided so as to surround the vibrating portion along the four outer edges of the vibrating portion, the vibration portion is supported. Is further strengthened, and there is an effect that it is possible to obtain a vibration element that is stronger in vibration, impact, and the like.

  Application Example 4 In the vibration element according to any one of the application examples described above, the substrate is a rotating Y-cut quartz crystal substrate.

  According to this configuration, it is possible to configure the vibration element having the required specifications with a more suitable cut angle by configuring the vibration element using the quartz crystal substrate cut at the above cutting angle, and There is an effect that a high-frequency vibration element having a frequency-temperature characteristic according to the specification, a small CI value, and a large CI value ratio can be obtained.

  Application Example 5 In the vibration element according to the application example described above, the third thick portion is on the + X axis side in plan view with respect to the vibration portion.

  According to this configuration, there is an advantage that a so-called X-long vibration element having a dimension in the X-axis direction larger than a dimension in the Z′-axis direction can be configured.

  Application Example 6 In the vibration element according to the application example, the fourth thick portion is on the −X axis side in a plan view with respect to the vibration portion.

  According to this configuration, there is an advantage that a so-called X-long vibration element having a dimension in the X-axis direction larger than a dimension in the Z′-axis direction can be configured.

  Application Example 7 In the resonator element according to the application example described above, the thickness of the third thick part increases as the distance from one end edge connected to the vibration part increases toward the other end edge. And a thick-walled portion main body provided continuously with the other end edge of the inclined portion.

  According to this configuration, there is an effect that it is possible to confine the vibration displacement in the vibration part and it is easy to hold the vibration part.

  Application Example 8 In the vibration element according to the application example described above, at least one slit is provided in the third thick portion.

  According to this configuration, by forming at least one slit in the third thick part, it is possible to suppress the spread of stress due to adhesion / fixation, so that the frequency temperature characteristic, the CI temperature characteristic, and the frequency aging characteristic are improved. There is an effect that an excellent vibration element can be obtained.

  Application Example 9 In the resonator element according to the application example, the slit is provided in the thick portion main body along a boundary portion between the inclined portion and the thick portion main body.

  According to this configuration, since the slit is provided in the thick portion main body along the boundary portion between the inclined portion and the thick portion main body, the spread of stress generated when the piezoelectric vibration element is bonded and fixed. Can be suppressed. Therefore, there is an effect that a piezoelectric vibration element having excellent frequency temperature characteristics, CI temperature characteristics, and frequency aging characteristics can be obtained.

  Application Example 10 In the vibration element according to the application example described above, the slit is disposed in the inclined portion so as to be separated from the third outer edge of the vibration portion.

  According to this configuration, since the slit is arranged in the inclined portion and away from the third outer edge of the vibration portion, the slit can be easily formed, and the spread of stress generated when the vibration element is bonded and fixed Therefore, it is possible to obtain a vibration element having excellent frequency temperature characteristics and CI temperature characteristics.

  Application Example 11 In the vibration element according to the application example described above, the slit is separated from the first slit disposed in the thick-walled portion main body and the third outer edge of the vibration portion in the inclined portion. And a second slit arranged.

  According to this configuration, since two slits are provided between the vibration part and the thick part main body, it is possible to better suppress the spread of stress generated when the vibration element is bonded and fixed, There is an effect that a vibration element can be obtained with excellent frequency reproducibility, frequency temperature characteristics, CI temperature characteristics, and frequency aging characteristics.

  Application Example 12 In the resonator element according to the application example, the first slit is disposed in the thick portion main body along the boundary portion between the inclined portion and the thick portion main body. And

  According to this configuration, it is possible to suppress the spread of stress generated when the vibration element is bonded and fixed, and there is an effect that the vibration element is excellent in frequency temperature characteristics and CI temperature characteristics.

  Application Example 13 A vibrator according to this application example includes the vibration element according to any one of the application examples described above and a package that houses the vibration element.

  According to this configuration, since the first thick part and the second thick part are provided, the support of the vibration part including the vibration part is strengthened, and the vibration element strong against vibration, impact, and the like is provided. Therefore, the vibration resistance and impact resistance of the vibrator can be improved. In addition to reducing the size of the fundamental wave vibrator at high frequency and suppressing the stress caused by adhesion and fixation, it has excellent frequency reproducibility, frequency temperature characteristics, CI temperature characteristics, and frequency aging characteristics. There is an effect that a vibrator is 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 vibration element having a large CI value ratio, and a vibrator having a small capacitance ratio can be obtained. is there.

  Application Example 14 An electronic device according to this application example is characterized in that the vibration element according to any one of the application examples described above and an electronic component are provided in a package.

According to this configuration, by selecting an electronic device based on customer requirements, the characteristics of the vibration element of the above application example 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.
Moreover, the electronic device which accommodated the vibration element and the electronic component (for example, thermistor) in the package is comprised. Since the thermistor, which is a temperature sensitive element, is arranged very close to the piezoelectric vibration element, there is an effect that a temperature change of the piezoelectric vibration element can be quickly detected. Further, by incorporating the electronic component, there is an effect that the burden on the device side to be used can be reduced.

  Application Example 15 In the electronic device according to the application example, the electronic component is at least one of a variable capacitance element, a thermistor, an inductor, and a capacitor.

  According to this configuration, when an electronic device (vibration device) is configured using any one of a variable capacitance element, a thermistor, an inductor, and a capacitor, a device suitable for the electronic device of required specifications is small and low cost. There is an effect that can be realized.

  Application Example 16 An electronic device according to this application example includes the vibration element according to any one of the application examples described above and an oscillation circuit that excites the vibration element in the package.

  According to this configuration, by selecting the electronic device based on the customer's request, the characteristics of the vibration element of the application example can be utilized, for example, frequency reproducibility, frequency temperature characteristics, aging characteristics are excellent, There is an effect that a small and high frequency (for example, 490 MHz band) electronic device can be obtained. Further, since the vibration device uses a vibration element of a fundamental wave, the capacitance ratio is small and the frequency variable width is widened. Furthermore, there is an effect that a voltage controlled oscillator having a good S / N ratio can be obtained.

  Application Example 17 An electronic apparatus according to this application example includes the vibration element according to any one of the application examples described above.

  According to this configuration, by using the vibrator according to the application example described above 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. .

  Application Example 18 An electronic apparatus according to this application example includes the electronic device according to the application example described above.

  According to this configuration, by using the electronic device of the application example described above 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. .

  Application Example 19 A moving object according to this application example includes the vibration element according to any one of the application examples described above.

  According to this configuration, since the vibration element used for the moving body is a vibration element resistant to vibration, impact, etc., there is an effect that a moving body with improved vibration resistance and impact resistance can be configured. . In addition, there is an effect that a moving body including a reference frequency source having a high frequency and excellent frequency stability and a good S / N ratio can be configured.

  Application Example 20 A method for manufacturing a vibrating element according to this application example is provided integrally with the vibrating unit along the vibrating unit and the first outer edge and the second outer edge of the vibrating unit facing each other. A first thick part that protrudes from one main surface of the vibration part and is thicker than the vibration part, a first thick part that protrudes from the main surface on the back side of the one main surface of the vibration part, and is thicker than the vibration part. And a step of preparing the substrate, and etching the substrate to etch the first thick portion and the second thickness. A thick portion forming step for forming a thick portion, a vibrating element outer shape forming step for forming an outer shape of the vibrating element by etching the substrate, and an electrode forming step for forming an electrode on the vibrating element. It is characterized by that.

  According to this manufacturing method, the vibration element according to the application example can be manufactured by using a simple processing process. For example, by forming a desired thick part at an arbitrary position on the front and back main surfaces, the vibration part including the vibration part is firmly supported, and a vibration element that is resistant to vibration, impact, etc. can be easily manufactured. There is an effect.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which showed the structure of the piezoelectric vibration element 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, and (d), (e), and (f) are cross sections of the QQ cross section showing a modification of the slit shape viewed from the + Z ′ direction. Figure. The figure explaining the relationship between an AT cut quartz substrate and a crystal axis. The top view which shows the modification of the piezoelectric vibration element of 1st Embodiment. The top view which shows the other modification of the piezoelectric vibration element of 1st Embodiment. It is the schematic which showed the structure of the piezoelectric vibration element 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 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. It is the schematic which showed the structure of the piezoelectric vibration element of the example of 4th Embodiment, (a) is a top view, (b) is sectional drawing which looked at PP cross section from + X-axis direction, c) is a cross-sectional view of the QQ cross section viewed from the + Z′-axis direction, and (d), (e), and (f) are QQ cross-sections showing a modification of the slit shape viewed from the + Z ′ direction. Sectional drawing. (A) is a top view which shows the structure of a lead electrode and a pad electrode, (b) is a top view which shows the structure of an excitation electrode. The top view which shows the modification of the piezoelectric vibration element of the example of 4th Embodiment. The top view which shows the other modification of the piezoelectric vibration element of the example of 4th Embodiment. It is the schematic which showed the structure of the piezoelectric vibration element of 5th 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′-axis direction. It is the schematic which showed the structure of the piezoelectric vibration element of 6th 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′-axis direction. The top view which shows the structure of the modification of the piezoelectric vibration element of 6th Embodiment. The top view which shows the structure of the modification of the piezoelectric vibration element of the example of 4th Embodiment. The schematic manufacturing-process figure which shows the external shape of a piezoelectric substrate, and the formation process of a slit. The schematic manufacturing process figure which shows the formation process of the excitation electrode and lead electrode of a piezoelectric vibration element. The schematic manufacturing process figure which shows the other formation process of the excitation electrode and lead electrode of a piezoelectric vibration element. (A) is a top view of the recessed part formed by the etching, (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 by the etching, (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. FIG. 2A is a perspective view showing a configuration of a piezoelectric vibration element according to a first embodiment, and FIG. 2B is a cross-sectional view of the QQ cross section of FIG. 1 viewed from the −Z′-axis direction. FIG. 6 is a view showing a modification of the piezoelectric vibration element of the first embodiment, and is a cross-sectional view of the QQ cross section of FIG. 1 as viewed from the −Z′-axis direction. It is a figure which shows the structure of a piezoelectric vibrator, Comprising: (a) is a longitudinal cross-sectional view, (b) is a top view except the cover part. The longitudinal cross-sectional view which shows the structure of the modification of a piezoelectric vibrator. The longitudinal cross-sectional view of an electronic device (piezoelectric device). (A) of an electronic device (piezoelectric device) is a longitudinal cross-sectional view, (b) is a top view. The longitudinal cross-sectional view of the modification of an electronic device. FIG. The perspective view which shows the structure of the mobile type personal computer as an example of an electronic device. The perspective view which shows the structure of the mobile telephone as an example of an electronic device. The perspective view which shows the structure of the digital camera as an example of an electronic device. The perspective view which shows the structure of the motor vehicle as an example of a mobile body. (A)-(c) is a perspective view of the modification of a piezoelectric substrate. (A)-(c) is a perspective view of the modification of a piezoelectric substrate. It is a modification of a piezoelectric vibration element, (a) is a top view, (b) is an enlarged view of the principal part, (c) is sectional drawing of the principal part.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment of Vibration Element]
FIG. 1 is a schematic diagram illustrating a configuration of a piezoelectric vibration element according to an embodiment of the vibration element of the present invention. The figure (a) is a top view, (b) is a sectional view which looked at PP section from + X-axis direction, (c) is a sectional view which looked at QQ section from + Z 'direction, (D), (e), and (f) are the sectional views which looked at the QQ section which shows the modification of a slit shape from the + Z 'direction.
The piezoelectric vibration element 1 includes a piezoelectric substrate 10 as a substrate having a thin flat plate-shaped vibrating portion 12 (hereinafter referred to as a vibrating portion 12) including a thin vibrating region and a thick portion 13 connected to the vibrating portion 12. Excitation electrodes 25a and 25b formed to face both main surfaces of the vibrating part 12, lead electrodes 27a and 27b extended from the excitation electrodes 25a and 25b to the thick part 13, respectively, and a lead electrode 27a , 27b, pad electrodes 29a, 29b connected to the respective ends.
Here, the two main surfaces refer to a combination of one main surface (also referred to as the front surface) and a main surface on the back side of the one main surface (also referred to as the back surface or the other main surface). 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. Moreover, the vibration part 12 means the thin part containing a vibration area | region and its peripheral part.

The piezoelectric substrate 10 has a rectangular shape and is a rectangular ring integrally provided with the vibrating portion 12 along the four sides of the vibrating portion 12 and the periphery (outer edge) of the vibrating portion 12, and is thicker than the vibrating portion 12. And a meat part 13. In other words, the thick portion 13 is provided so as to protrude from either of the two main surfaces of the vibrating portion 12.
The thick part 13 includes a first thick part 16, a second thick part 17, a third thick part 15, and a fourth thick part 14.
The first thick part 16 and the second thick part 17 are along the side 12c as the first outer edge and the side 12d as the second outer edge that face each other via the vibration part 12. Is provided. The fourth thick part 14 and the third thick part 15 are provided along the side 12a as the fourth outer edge and the side 12b as the third outer edge that face each other via the vibration part 12. It has been.
The two pairs of opposing sides 12c and 12d and sides 12a and 12b are arranged so as to be substantially parallel to each other with the vibrating part 12 interposed therebetween.

The fourth thick portion 14 is provided continuously along the side 12a of the vibrating portion 12 between the other end portions of the first thick portion 16 and the second thick portion 17, Projected on the main surface side. That is, the fourth thick part 14 is formed on the −X axis side of the vibration part 12. In addition, a fourth inclined portion 14b having a thickness that gradually increases as it is separated from one edge connected to the side 12a of the vibrating portion 12 to the other edge on the −X axis side, and a fourth inclined portion 14b. A fourth thick-walled main body 14a in the shape of a thick quadrangular column that is connected to the other end edge of the second thick-walled portion 14a. That is, as shown in FIG. 1C, the fourth thick portion 14 is formed so as to protrude from both main surfaces (front surface and back surface) of the vibration portion 12.
Similarly, the third thick portion 15 is continuously provided along the side 12b of the vibrating portion 12 between one end of each of the first thick portion 16 and the second thick portion 17. However, it is provided on both main surfaces. That is, the third thick part 15 is formed on the + X axis side of the vibration part 12. The third inclined portion 15b, the thickness of which gradually increases as the distance from the one edge connected to the side 12b of the vibrating portion 12 to the other edge on the + X-axis side, and the other of the third inclined portions 15b And a thick quadrangular columnar third thick portion main body 15a provided continuously with the end edge. That is, as shown in FIG. 1C, the third thick part 15 is formed so as to protrude from both surfaces (the front surface and the back surface) of the main surface of the vibration unit 12.
The thick part main body (the fourth thick part main body 14a, the third thick part main body 15a, etc.) refers to a region having a constant thickness substantially parallel to the Y ′ axis.

The first thick part 16 is provided so as to protrude from one main surface along the side 12 c of the vibration part 12. That is, the first thick part 16 is formed on the + Z ′ axis side of the vibration part 12 on the surface side. In addition, a first inclined portion 16b that gradually increases in thickness as it is separated from one edge connected to the side 12c of the vibrating portion 12 to the other edge on the + Z′-axis side, and a first inclined portion 16b A thick quadrangular columnar first thick portion main body 16a provided continuously with the other end edge. That is, one main surface of the first thick portion 16 is formed so as to protrude from one main surface (surface) of the vibrating portion 12. The other main surface of the first thick portion 16 and the other main surface of the vibrating portion 12 (the main surface on the back side of the one main surface) are continuously connected to be the same surface. It is configured. Even in the case where the vibration region has a protruding energy confinement region on the mesa, the main surface of the peripheral portion of the vibration region is continuously connected to the other main surface of the first thick portion 16 and is the same. What is necessary is just to be comprised so that it may become a surface.
In the present embodiment, the other main surface of the first thick portion 16 and the other main surface of the vibrating portion 12 are continuously connected and configured to be the same surface. Although the influence of the residue on the vibration part 12 is small, i.e., does not affect the effective area of the vibration area of the vibration part 12, the other main surface of the first thick part 16 is vibrated. The portion 12 may slightly protrude from the other main surface.

The second thick portion 17 is provided so as to protrude from the main surface on the back side with respect to one main surface along the side 12 d of the vibration portion 12. That is, the first thick part 16 is formed on the −Z ′ axis side of the vibration part 12 on the back surface side. In addition, a second inclined portion 17b having a thickness that gradually increases from one edge connected to the side 12d of the vibrating portion 12 to the other edge on the −Z′-axis side, and a second inclined And a thick quadrangular columnar second thick portion main body 17a provided continuously with the other end edge of the portion 17b. That is, one main surface of the second thick portion 17 is formed so as to protrude from the other main surface (back surface) of the vibrating portion 12, and the second thick portion 17 is formed in the vibrating portion 12. The other thick portions of the fourth thick portion 14 and the third thick portion 15 are connected to each other on the back side. And the other main surface of the 2nd thick part 17 and one main surface of the vibration part 12 are connected continuously, and it is comprised so that it may become the same surface. Even when 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 second thick portion 17 and is the same. What is necessary is just to be comprised so that it may become a surface.
In the present embodiment, the other main surface of the second thick portion 17 and the other main surface of the vibration portion 12 are continuously connected and configured to be the same surface. Although the influence of the residue on the vibration part 12 is small, that is, the other main surface of the second thick part 17 is vibrated to such an extent that the effective area of the vibration area of the vibration part 12 is not affected. The portion 12 may slightly protrude from the other main surface.

  The first thick part 16 and the second thick part 17 have a point-symmetric relationship with respect to the center of the vibration part 12 as shown in FIG. In addition, one surface (front surface) of each of the fourth thick portion main body 14a and the third thick portion main body 15a is flush with one surface (front surface) of the first thick portion main body 16a. The other surface (back surface) of each of the fourth thick portion main body 14a and the third thick portion main body 15a and the surface (back surface) of the second thick portion main body 17a are on the same plane. . The first, second, third, and fourth thick portions 16, 17, 15, and 14 are connected at their ends to form a square ring shape, and the vibrating portion 12 is held at the center thereof. ing.

The substantially rectangular vibrating portion 12 is surrounded by first, second, third, and fourth thick portions 16, 17, 15, 14 on the four sides of the periphery. That is, etching is performed from both main surfaces of the rectangular flat plate-shaped piezoelectric substrate 10 to form two concave portions opposed to the two main surfaces, and unnecessary portions are cut to reduce the size, and the thin vibrating portion 12 is formed. Is forming.
Further, in the piezoelectric substrate 10, at least one stress relaxation slit 20 is formed through the third thick portion 15. In the embodiment shown in FIG. 1, the slit 20 is formed along the boundary portion (joint portion) between the third inclined portion 15 b and the third thick portion main body 15 a that are separated from the side 12 b of the vibrating portion 12. 3 in the plane of the thick portion main body 15a.
As described above, since the slit 20 is disposed apart from the side 12b of the vibrating portion 12, the slit can be easily formed, and further to the boundary portion (joining portion) of the third thick portion main body 15a. Since they are arranged close to each other, a large area of the supported portion (pad electrode) 29a of the third thick portion main body 15a can be secured, and the diameter of the conductive adhesive to be applied can be increased. On the other hand, when the slit 20 is disposed near the supported portion (pad electrode) 29a of the third thick portion main body 15a, the area of the supported portion (pad electrode) 29a is reduced, and the conductive adhesive The diameter of the 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 disposed close to the boundary portion (connecting portion) of the third thick portion main body 15a.

The slit 20 is not limited to a through-hole formed as shown in FIG. 1C, and may be a groove-shaped slit having a bottom. The groove-shaped slit will be described in detail. For example, as shown in FIG. 1 (d), a first slit 20a ′ having a bottom portion formed from the back surface side of the third thick portion 15 and a third thickness is provided. You may comprise by the slit provided from the front and back both surfaces side of 2nd slit 20b 'which is formed from the surface side of the meat | flesh part 15, and has a bottom part. Moreover, as shown in FIG.1 (e), you may be comprised from 3rd slit 20c 'which is formed from the back surface side of the 3rd thick part 15, and has a bottom part. Moreover, as shown in FIG.1 (f), the structure provided from the surface side of the 3rd thick part 15 and the 4th slit 20d 'which has a bottom part may be provided.
In addition, the slit according to the present invention is surrounded by the third thick portion 15 in plan view, and when the slit as shown in FIGS. 1D to 1F is a bottomed groove, the slit The bottom portion may be thicker than the vibrating portion, or may be thinner.
The shape of the slit 20 described here can be applied to other embodiments, modifications, and application examples described below.

  As an example of the piezoelectric substrate 10, a piezoelectric material such as quartz belongs to a trigonal system, and as shown in FIG. 2, orthogonal coordinates composed of an X axis (electric axis), a Y axis (mechanical axis), and a Z axis (optical axis). Centered on the X axis of the system, the Z axis is tilted in the −Y direction of the Y axis as the Z ′ axis, the Y axis is tilted in the + Z direction of the Z axis as the Y ′ axis, and the X axis and Z ′ This is a rotating Y-cut quartz substrate that is formed of a plane parallel to the axis and has a thickness in a direction parallel to the Y ′ axis. In the present embodiment, an AT cut crystal substrate which is an example of a rotated Y cut crystal substrate is described.

The AT-cut quartz substrate is a flat plate cut out from quartz along a plane obtained by rotating the XZ plane about the X axis by an angle θ as shown in FIG. In the case of an AT-cut quartz substrate, 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 substrate has crystal axes X, Y ′, and Z ′ that are orthogonal to each other. The AT-cut quartz substrate has a Y 'axis in the thickness direction, and an XZ ′ plane (plane including the X axis and Z ′ axis) orthogonal to the Y ′ axis is the main surface, and thickness shear vibration is excited as the main vibration. Is done.
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 unit 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 extends from the vibration part 12 to the surface of the third thick part body 15a via the first inclined part 16b and the surface of the first thick part body 16a. The formed lead electrode 27a is electrically connected to the pad electrode 29a formed on the surface of the third thick portion main body 15a. In addition, the excitation electrode 25b formed on the back surface side is connected to the third thick portion main body 15a from above the vibration portion 12 via the surface of the second inclined portion 17b and the second thick portion main body 17a. The lead electrode 27b formed up to the back surface of the first conductive layer is electrically connected to the pad electrode 29b formed on the back surface of the third thick portion main body 15a.

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 part 12 and the pad electrodes 29a and 29b that are supported parts 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 electrodes 29a and 29b of the piezoelectric vibration element 1 are supported on the package using a conductive adhesive, first, the conductive adhesive is attached to the supported portion (pad electrode) 29a of the third thick portion main body 15a. Apply an agent, reverse it, place it on a device mounting pad such as a package, and hold it down 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 third thick portion main body 15a and the package both expand and the adhesive temporarily softens, so that no stress is generated in the supported portion (pad electrode) 29a. After the conductive adhesive is cured, when the third thick part body 15a and the package are cooled and the temperature returns to room temperature (25 ° C.), the conductive adhesive, the package, and the third thick part Due to the difference between the linear expansion coefficients of the main body 15a, the stress generated from the cured conductive adhesive is transmitted to the supported portion (pad electrode) 29a, and further from the third thick portion main body 15a to the fourth thick portion 14 and the fourth thick portion 14a. 1 thick portion 16 and vibration portion 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. The smaller the stress in the vibration part 12, the better the piezoelectric vibration element with excellent frequency temperature characteristics, frequency reproducibility, and frequency aging characteristics.
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 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. The frequency change is smaller when force is applied to both ends in the Z′-axis direction. 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 vibrating portion 12 is rectangular, but both angles corresponding to both end portions of the side 12 c connected to the first thick portion 16 of the thin vibrating portion 12. The corner may be chamfered.

In the embodiment shown in FIG. 1, the excitation electrodes 25a and 25b 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.

[Second Embodiment of Vibration Element]
FIG. 5 is a schematic diagram illustrating a configuration of the piezoelectric vibration element 2 according to the second embodiment of the vibration element. 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 + Z ′. It is sectional drawing 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 this embodiment, the slit 20 is formed in the third inclined portion 15b that is separated from the side 12b of the thin vibrating portion 12. Instead of forming the slit 20 in the third inclined portion 15b so that one edge of the slit 20 is in contact with the side 12b along the side 12b of the vibrating unit 12 as in the piezoelectric vibration element 1, Slits 20 are provided apart from both end edges of the third inclined portion 15b. That is, in the third inclined portion 15b, an extremely thin inclined portion 15b ′ connected to the edge of the side 12b of the vibrating portion 12 is left. In other words, an extremely fine inclined portion 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 excitation electrodes 25a and 25b are formed on the vibration part 12 and a high-frequency voltage is applied and excited, 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 part 12 becomes thin and the fundamental wave frequency becomes several hundred MHz, it is necessary to make the thickness of the excitation electrodes 25a and 25b 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 part 12 in FIG. 5 is point-symmetric with respect to the center of gravity of the vibration part 12 as shown in FIG. The shape also becomes asymmetric by leaving the extremely thin inclined portion 15b ', and the amplitude of the low-order inharmonic mode standing wave can be suppressed.

[Third Embodiment of Vibration Element]
FIG. 6 is a schematic diagram illustrating a configuration of the piezoelectric vibration element 3 according to the third embodiment of the vibration element. 6A is a plan view of the piezoelectric vibration element 3, FIG. 6B is a cross-sectional view of the P-P cross section viewed from the + X-axis direction, and FIG. 6C is a cross-sectional view of the QQ cross-section + Z ′. It is sectional drawing 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 20 a and 20 b are provided in parallel in the third thick portion 15. That is, the first slit 20a is provided in the surface of the third thick portion main body 15a, and the second slit 20b is formed in the surface of the third inclined portion 15b.
By forming individual slits in the surface of the third thick portion main body 15a and in the surface of the third inclined portion 15b, the spread of stress generated when the piezoelectric vibration element 3 is bonded and fixed is further increased. The piezoelectric vibration element 3 that can be well suppressed and is excellent in frequency reproducibility, frequency temperature characteristics, CI temperature characteristics, and frequency aging characteristics is obtained.

  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 spread to the vibration part 12. Further, the configuration of the modification shown in FIG. 7B is a piezoelectric vibration element 3 that has the effects of the slits 20, 20a, and 20b shown in FIGS. 1 and 6, respectively. Are formed across the inclined portion 15b and the third thick portion main body 15a.

[Fourth Embodiment of Vibration Element]
FIG. 8 is a schematic diagram showing the configuration of the piezoelectric vibration element 4 according to the fourth embodiment of the vibration element. 8A is a plan view of the piezoelectric vibration element 4, FIG. 8B is a cross-sectional view of the PP cross section viewed from the + X axis direction, and FIG. 8C is a cross section of the QQ cross section viewed from the + Z ′ axis direction. It is sectional drawing.
The piezoelectric vibration element 4 includes a rectangular vibration portion 12 including a thin vibration region, a piezoelectric substrate 10 that is integrated with the vibration portion 12 and has a thick portion 13 that is thicker than the vibration portion 12, and the front and back surfaces of the vibration portion 12. Excitation electrodes 25a and 25b respectively disposed on the (both main surfaces) and extending from the respective excitation electrodes 25a and 25b toward the pad electrodes 29a and 29b provided on the respective thick portions 13, respectively. Lead electrodes 27a and 27b.

  The thick portion 13 is provided continuously along the side 12a of the vibration portion 12, and is provided with a third thick portion 15 projecting (protruding) on both main surfaces, and one end portion of the side 12a of the vibration portion 12. The first thick portion 16 is provided continuously along the side 12b, and is connected to one end portion of the third thick portion 15 on one main surface side (surface side) of the vibrating portion 12. And. Furthermore, the thick portion 13 is provided continuously along the side 12c that is continuous with the other end of the side 12a of the vibration portion 12, and the third main thickness side (back side) of the vibration portion 12 has a third thickness. And a second thick part 17 connected to the other end of the meat part 15. That is, the piezoelectric substrate 10 includes the thick-walled thick portion 13 (the first thick-walled portion 16, the second thick-walled portion 17, and the first thick-walled portion 17, integrated along the three sides 12a, 12b, and 12c of the vibrating portion 12. 3, and the first thick part 16 and the second thick part 17 are arranged symmetrically with respect to the center of gravity of the vibration part 12. The two sides 12b and 12c face each other and are arranged so as to be substantially parallel to each other with the vibration part 12 interposed therebetween.

One main surface of the first thick portion 16 is formed so as to protrude from one main surface (surface) of the vibrating portion 12. The other main surface of the first thick portion 16 and the other main surface of the vibrating portion 12 are continuously connected to each other and are configured to be the same surface.
One main surface of the second thick portion 17 is formed so as to protrude from the other main surface (back surface) of the vibrating portion 12. And the other main surface of the 2nd thick part 17 and one main surface of the vibration part 12 are connected continuously, and it is comprised so that it may become the same surface.
Even in the case where there is a mesa-shaped protruding energy confinement region 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 second thick portion 17 and is the same. What is necessary is just to be comprised so that it may become a surface.

The third thick part 15 is connected to the side 12a of the vibration part 12, and extends from one end edge (inner end edge) connected to the side 12a of the vibration part 12 to the other end edge (outer end edge). A third inclined portion 15b having a thickness that gradually increases as the distance from the third inclined portion 15b increases, and a third thick portion main body 15a having a thick quadrangular prism shape that is connected to the other end edge (outer end edge) of the third inclined portion 15b. And.
Similarly, the first thick part 16 is connected to the side 12b of the vibration part 12 and from one edge (inner edge) connected to the side 12b of the vibration part 12 to the other edge (outer edge). The first inclined portion 16b having a thickness that gradually increases as the distance from the first inclined portion 16b increases, and a thick quadrangular prism-shaped first thick portion that is connected to the other end (outer end edge) of the first inclined portion 16b. Part main body 16a.
The second thick part 17 is connected to the side 12c of the vibration part 12 and from one end edge (inner end edge) connected to the side 12c of the vibration part 12 to the other end (outer end edge). A second inclined portion 17b having a thickness that gradually increases as the distance from the second inclined portion 17b increases, and a thick quadrangular prism-shaped second thick portion that is connected to the other end edge (outer end edge) of the second inclined portion 17b. And a main body 17a.
In addition, at least one slit 20 is formed through the third thick portion 15.

One surface (surface side) of each of the third thick portion 15 and the first thick portion 16 is on the same plane, that is, the XZ ′ plane of the coordinate axis shown in FIG. The other surface (back surface side) of the thick portion 15 and the back surface of the second thick portion 17 are on the same plane (on the XZ ′ plane).
In other words, the other main surface (back surface) of the vibration part 12 and the other surface (back surface) of the first thick part 16 are on the same plane, and one main surface (front surface) of the vibration part 12. And the other surface (surface) of the second thick portion 17 is on the same plane. That is, unnecessary thick portions are reduced.
Further, the third thick part 15 protrudes from the front and back surfaces (both sides) of the vibration part 12. In addition, the first thick part 16 and the second thick part 17 are each symmetric with respect to the center of the vibration part 12 as shown in FIG. It protrudes only on one side.
The third thick portion 15 has at least one stress relaxation slit 20 between the vibrating portion 12 and the pad electrodes 29a and 29b, which are supported portions, along the Z′-axis direction. It is formed through. In the embodiment shown in FIG. 8, the slit 20 is formed in the third thick portion main body 15a along the boundary portion (connecting portion) between the third inclined portion 15b and the third thick portion main body 15a. Is formed.
The thick part main body (15a, 16a, 17a) refers to a region having a constant thickness in the Y′-axis direction.

Further, the slit 20 is not limited to a through-hole formed as shown in FIG. 8C, and may be a groove-shaped slit having a bottom. The groove-shaped slit will be described in detail. For example, as shown in FIG. 8D, a first slit 20a ′ having a bottom portion formed from the surface side of the third thick portion 15 and a third thickness is provided. You may comprise by the slit provided from the front and back both surfaces side of 2nd slit 20b 'which is formed from the back surface side of the meat | flesh part 15, and has a bottom part. Moreover, as shown in FIG.8 (e), you may be comprised from 3rd slit 20c 'which is formed from the surface side of the 3rd thick part 15, and has a bottom part. Moreover, as shown in FIG.8 (f), the structure provided with 4th slit 20d 'which is formed from the back surface side of the 3rd thick part 15, and has a bottom may be sufficient.
The shape of the slit 20 described here can be applied to other embodiments, modifications, and application examples described below.

  Descriptions similar to those in the first embodiment, such as the configuration of the electrodes such as the excitation electrodes 25a and 25b and the lead electrodes 27a and 27b that drive the piezoelectric substrate 10 and the reason why the slit 20 is provided, are omitted.

FIG. 9 is a plan view showing components of the piezoelectric vibration element 4. FIG. 9A is a plan view showing the arrangement and configuration of the lead electrodes 27a and 27b and the pad electrodes 29a and 29b formed on the piezoelectric substrate 10, and FIG. 9B shows the excitation electrodes 25a and 25b. It is a top view which shows arrangement | positioning and a structure. The lead electrode 27a extends from the edge of the assumed excitation electrode 25a on the surface side, and is provided on the surface of the central portion of the third thick portion 15 via the surface of the first thick portion 16. It forms so that it may connect with the pad electrode 29a. Further, the lead electrode 27b extends from the end edge of the excitation electrode 25b assumed on the back surface side, passes through the surface of the second thick portion 17 on the back surface side, and reaches the center portion of the third thick portion 15. It forms so that it may connect with the pad electrode 29b provided in the back surface.
Each of the lead electrodes 27a and 27b includes a first layer made of a chromium (Cr) thin film and a second layer made of a gold (Au) thin film laminated on the first layer. A cross-sectional view taken along the line RR, in which a part of the lead electrode 27a is enlarged, is shown in a broken line circle 27A on the left side in FIG. 9A. The lead electrode 27a has a chromium (Cr) thin film 27c as a base on the surface side (upper surface side) of the first thick part 16 and the third thick part 15, and a gold (Au) thin film 27g thereon. Are stacked to form a film. The lead electrode 27b is configured similarly.

The pad electrodes 29a and 29b provided on the front and back surfaces of the central portion of the third thick portion 15 are composed of a first layer made of a chromium (Cr) thin film and gold laminated on the first layer ( And a second layer made of a thin film of Au). A cross-sectional view taken along line T-T in which a part of the pad electrode 29a is enlarged is shown in a lower broken line circle 29A in FIG. 9A. The pad electrode 29a is formed by laminating a chromium (Cr) thin film 29c on the surface side (upper surface side) of the third thick portion 15 and a gold (Au) thin film 29g thereon. The pad electrode 29b is configured similarly.
Since the lead electrodes 27a, 27b and the pad electrodes 29a, 29b are formed in the same process, an example of the film thickness is that the first layer of chromium (Cr) thin films 27c, 29c is 100 mm (1 mm = 0.1 nm). (Nanometer)), the gold (Au) thin films 27g and 29g of the second layer are formed as thick as 2000 mm. For this reason, the ohmic cross of the lead electrodes 27a and 27b and the pad electrodes 29a and 29b does not occur, and the bonding strength is sufficient.
Note that another metal film may be sandwiched between a chromium (Cr) thin film and a gold (Au) thin film.

FIG. 9B is a plan view showing the arrangement and configuration of the excitation electrodes 25a and 25b formed on the piezoelectric substrate 10 so as to be aligned with the lead electrodes 27a and 27b formed in the previous step. The excitation electrode 25a is formed on the front surface side of the piezoelectric substrate 10, and the excitation electrode 25b that is sufficiently larger than the area of the excitation electrode 25a and within which the excitation electrode 25a fits is formed on the back surface side. An example of the configuration of the excitation electrodes 25a and 25b includes a first layer made of a nickel (Ni) thin film and a second layer made of a gold (Au) thin film laminated on the first layer. . A cross-sectional view of the excitation electrodes 25a and 25b and a U-U line of a broken-line circle is shown in a broken-line circle on the right side in FIG. 9B. A nickel (Ni) thin film 25n is formed on the first layer on the front and back surfaces of the vibration unit 12, and a gold (Au) thin film 25g is formed on the second layer. As an example of the film thickness, the first layer of nickel (Ni) thin film 25n is 70 mm, and the second layer of gold (Au) thin film 25g is 600 mm.
Note that another metal film may be sandwiched between a nickel (Ni) thin film and a gold (Au) thin film.

  The reason why the electrode materials and the electrode film thicknesses of the lead electrodes 27a and 27b and the pad electrodes 29a and 29b and the excitation electrodes 25a and 25b are made different will be described below. The fundamental frequency of the vibration part 12 of the piezoelectric substrate 10 is set to 490 MHz, for example. The lead electrodes 27a and 27b, the pad electrodes 29a and 29b, and the excitation electrodes 25a and 25b are composed of, for example, a 70-thick nickel (Ni) thin film as the first layer and a 600-thick gold (Au) thin film as the second layer. Suppose that The main vibration is sufficiently confined and its crystal impedance (CI; equivalent resistance) is expected to be small. However, since the gold (Au) film thickness of the lead electrodes 27a and 27b is thin, a thin film ohmic cross is generated, and the CI value of the piezoelectric vibration element 4 may be increased. Further, if the pad electrodes 29a and 29b are composed of a 70 mm nickel (Ni) thin film and a 600 mm gold (Au) thin film, the wire bonding strength may be insufficient.

  Further, the lead electrodes 27a and 27b, the pad electrodes 29a and 29b, and the excitation electrodes 25a and 25b are formed, for example, as a first layer of 70 ク ロ ム chromium (Cr) thin film and a second layer of 600 金 gold (Au) thin film. In this case, since the gold (Au) thin film is thin, chromium (Cr) is diffused into the gold (Au) thin film by heat, and the thin film ohmic cross is generated, which may increase the CI value of the main vibration. There is.

  Therefore, the formation process of the lead electrodes 27a and 27b, the pad electrodes 29a and 29b, and the excitation electrodes 25a and 25b is separated, and the material and film thickness of each electrode thin film are optimized for the function of each thin film. I decided to set it to be. That is, the excitation electrodes 25a and 25b have the main vibration as a confinement mode, and the adjacent in-harmonic overtone mode becomes a propagation mode (non-confinement mode) as much as possible. A thin film of Ni) was set as thin as 70 mm and a thin film of gold (Au) as 600 mm. On the other hand, the lead electrodes 27a and 27b and the pad electrodes 29a and 29b have a chromium (Cr) film thickness of 100 mm and gold (Au) in order to reduce the film resistance of the thin lead electrode and increase the bonding strength of bonding. The film thickness was set as thick as 2000 mm.

The above film thickness is an example, and the present invention is not limited to this value, and is changed according to the difference in the frequency of the vibrating portion 12. In short, in consideration of the energy confinement theory and the thin film ohmic cross, the excitation electrodes 25a and 25b may be made of a multilayer film of nickel (Ni) and gold (Au) having an optimum film thickness. The lead electrodes 27a and 27b and the pad electrodes 29a and 29b are formed in a laminated film of chromium (Cr) and gold (Au) having a necessary thickness in consideration of the thin film ohmic cross and the bonding strength. May be used.
A method for manufacturing the excitation electrodes 25a and 25b, the lead electrodes 27a and 27b, and the pad electrodes 29a and 29b will be described later.

In the fourth embodiment shown in FIG. 8, the excitation electrodes 25 a and 25 b have a quadrilateral shape, that is, a square shape or a rectangular shape (with the long side in the X-axis direction). Absent.
In the embodiment shown in FIG. 10, the excitation electrode 25a on the front surface side is circular, the excitation electrode 25b on the back surface side is sufficiently larger than the area of the excitation electrode 25a, and the rectangular shape in which the excitation electrode 25a fits within the area. Electrode. Further, the excitation electrode 25b on the back surface side may be a circle having a sufficiently large area.
In the embodiment shown in FIG. 11, the excitation electrode 25a on the front surface side is an ellipse, the excitation electrode 25b on the back surface side is sufficiently larger than the area of the excitation electrode 25a, and the rectangle in which the excitation electrode 25a fits within the area. Electrode. When the piezoelectric substrate 10 is quartz, 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 by a plane parallel to the XZ ′ plane. Becomes oval. Therefore, the piezoelectric vibration element 4 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 4 can be minimized. The excitation electrode 25a may be oval. Further, the excitation electrode 25b on the back surface side may be a circle, an ellipse, an ellipse, or the like that is sufficiently larger than the area of the excitation electrode 25a and within which the excitation electrode 25a fits.

[Fifth Embodiment of Vibration Element]
FIG. 12 is a schematic diagram illustrating a configuration of a piezoelectric vibration element according to the fifth embodiment of the vibration element. 12A is a plan view of the piezoelectric vibration element 6, FIG. 12B is a cross-sectional view of the PP cross section viewed from the + X axis direction, and FIG. 12C is a cross section of the QQ cross section viewed from the + Z ′ axis direction. It is sectional drawing.
The piezoelectric vibrating element 6 is different from the piezoelectric vibrating element 4 shown in FIG. 8 in the position where the stress relaxation slit 20 is provided. In this example, the slit 20 is formed through and formed in the third inclined portion 15b that is separated from the edge of the side 12a of the thin vibrating portion 12. Instead of forming the slit 20 in the third inclined portion 15b so that one end edge of the slit 20 is in contact with the side 12a along the side 12a of the vibrating unit 12 as in the piezoelectric vibration element 4, Slits 20 are provided apart from both end edges of the third inclined portion 15b. That is, in the third inclined portion 15b, an extremely thin inclined portion 15bb connected to the edge of the side 12a of the vibrating portion 12 is left. In other words, an extremely fine inclined portion 15bb is formed between the side 12a and the slit 20.

The reason for leaving the ultra-thin inclined portion 15bb is as follows. That is, when the vibration unit 12 is excited by applying a high frequency voltage to the excitation electrodes 25a and 25b arranged in the vibration unit 12, the inharmonic overtone mode (A0, S1, A1, S2) in addition to the main vibration (S0).・ ・) Is excited. Desirably, only the main vibration (S0) mode is set as the confinement mode, and the other inharmonic overtone mode is set as the propagation mode (unconfined mode). However, when the vibration part 12 becomes thin and the fundamental frequency becomes as high as several hundred MHz, the excitation electrodes 25a and 25b need to have a predetermined thickness or more in order to avoid ohmic cross of the electrode film. For this reason, when the thickness of the excitation electrodes 25a and 25b is equal to or greater than the predetermined thickness, the low-order inharmonic overtone mode close to the main vibration becomes the confinement mode.
In order to suppress the magnitude (CI) of the amplitude of the low-order inharmonic overtone mode, it is only necessary to prevent the condition that the standing wave of the inharmonic overtone mode is established. That is, the shape of the both end edges in the X-axis direction of the vibration part 12 in FIG. 12 becomes asymmetric because the strip (extra fine inclined part 15bb) remains, and the amplitude of the standing wave in the low-order inharmonic overtone mode is Can be suppressed.

[Sixth Embodiment of Vibration Element]
FIG. 13 is a schematic diagram illustrating a configuration of a piezoelectric vibration element according to a sixth embodiment of the vibration element. 13A is a plan view of the piezoelectric vibration element 7, FIG. 13B is a cross-sectional view of the PP cross section viewed from the + X axis direction, and FIG. 13C is a cross section of the QQ cross section viewed from the + Z ′ axis direction. It is sectional drawing.
The piezoelectric vibrating element 7 is different from the piezoelectric vibrating element 4 shown in FIG. 8 in that two stress relaxation slits are provided. That is, the first slit 20a is formed through the third thick portion main body 15a, and the second slit 20b is formed through the third inclined portion 15b. Since the purpose of providing the individual slits 20a and 20b in the third thick portion main body 15a and the third inclined portion 15b has already been described, it is omitted here.

  FIG. 14 is a plan view showing a configuration of a modification of the piezoelectric vibration element 7 shown in FIG. In the piezoelectric vibration element 7 ′, the first slit 20 a is formed to penetrate in the third thick part main body 15 a, and the second slit 20 b is formed to penetrate in the third inclined part 15 b. However, the first slit 20a and the second slit 20b are not arranged in parallel with the first slit 20a and the second slit 20b in the X-axis direction as shown in the plan view of FIG. However, the piezoelectric vibration element 7 is different from the piezoelectric vibration element 7 in that it is staggered in the Z′-axis direction. By providing the two slits 20a and 20b, it is possible to prevent the stress caused by the conductive adhesive from spreading to the vibrating portion 12.

FIG. 15 is a plan view showing a configuration of a modification of the piezoelectric vibration element 4 of the embodiment shown in FIG. In the piezoelectric vibration element 4 ′, the lead electrode 27 a extends from the edge of the excitation electrode 25 a on the surface, passes through the surface (upper surface) of the first thick portion 16, and the surface of the third thick portion 15. The pad electrode 29a is connected to the pad electrode 29a. The lead electrode 27 b extends from the edge of the excitation electrode 25 b on the back surface side, passes through the surface side of the second thick portion 17, and is provided on the back surface side of the third thick portion 15. In this configuration, the electrode 29b is connected.
A difference from the piezoelectric vibration element 4 of the embodiment shown in FIG. 8 is a position where the pad electrodes 29a and 29b are arranged. The pad electrodes 29a and 29b are provided apart from each other on the surface of the third thick portion main body 15a. The pad electrode 29b is formed of a conductive thin film from the back surface to the surface across the edge of the piezoelectric substrate 10 so as to be electrically connected to the lead electrode 27b formed on the back surface. The pad electrodes 29a and 29b are configured so that conduction is easily achieved when a conductive adhesive is applied to the pad electrodes 29a and 29b on the surface side, and is inverted and placed on the element mounting pad of the package. Has been.

[Manufacturing method of vibration element]
(Element outline forming process)
FIG. 16 is a schematic manufacturing process diagram 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 a piezoelectric wafer, and a manufacturing process for forming a plurality of piezoelectric vibrating elements 1 on the quartz wafer 10W will be described. Show.
In step S1, a quartz wafer 10W having a predetermined thickness (for example, 80 μm) on which both (front and back) surfaces are polished 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 thereon.
In step S2, a photoresist film (referred to as a resist film) R is applied to the upper surfaces of the metal films M on the front and back surfaces.
In step S3, the resist film R in a portion corresponding to the recessed portions 11 and 11 ′ on the front and back surfaces is exposed using an exposure apparatus and a mask pattern. When the resist film R exposed by exposure is developed and peeled off, the metal film M at a position corresponding to the recessed portions 11 and 11 ′ on the front and back surfaces is exposed. When each gold layer film M exposed by peeling off the resist film R is dissolved and removed using a solution such as aqua regia, the front and back surfaces of the quartz wafer 10W at positions corresponding to the recessed portions 11 and 11 ′ are exposed.

In step S4, the front and back surfaces of the exposed quartz wafer 10W are etched to a desired thickness using a mixed liquid of hydrofluoric acid (hydrofluoric acid) and ammonium fluoride.
In step S5, the resist film R on the front and back surfaces is removed using a predetermined solution, and the exposed metal film M on the front and back surfaces is removed using aqua regia or the like. In plan view at this stage, the quartz wafer 10W is formed such that the concave and convex portions 11 and 11 ′ on the front and rear surfaces are slightly shifted from each other, and the same surface is regularly arranged in a lattice pattern.
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, using the exposure apparatus and a predetermined mask pattern, the resist film R in a portion corresponding to the outer shape of the piezoelectric substrate 10 and the slit (not shown) is exposed from both the front and back surfaces, developed, Each resist 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, both surfaces of the exposed quartz wafer 10W are etched using a mixed liquid of hydrofluoric acid (hydrofluoric acid) and ammonium fluoride to form the outer shape of the piezoelectric substrate 10 and slits (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 quartz wafer 10W is in a state in which a plurality of piezoelectric substrates 10 are connected by support strips and regularly arranged in a lattice shape. In the present embodiment, as shown in step S <b> 10, the concave portions 11 and 11 ′ are formed on both main surfaces of the piezoelectric substrate 10 to form the vibrating portion 12, and the first and second connected to the vibrating portion 12 are provided. The thick portions 16 and 17 are formed point-symmetrically with respect to the center of gravity of the piezoelectric substrate 10.
After step S10 is completed, the thicknesses of the vibrating portions 12 of the plurality of piezoelectric substrates 10 regularly arranged in a lattice pattern on the quartz wafer 10W are measured using, for example, an optical technique. When the measured thickness of each vibration part 12 is thicker than a predetermined thickness, the thickness is finely adjusted so as to fall within the predetermined thickness range.

(Element Electrode Formation Step-1)
After adjusting the thickness of the vibrating portions 12 of the plurality of piezoelectric substrates 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 applied to each piezoelectric substrate 10. A procedure (process) for forming the substrate will be described with reference to a schematic manufacturing process diagram 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 left, and the unexposed 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 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. Thereafter, the support strips formed by half etching connected to the plurality of piezoelectric substrates 10 of the quartz wafer 10W are broken to obtain the piezoelectric vibration element 1 which is divided into individual pieces.

(Element electrode formation step-2)
After adjusting the thickness of the vibrating portions 12 of the plurality of piezoelectric substrates 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 applied to each piezoelectric substrate 10. Another procedure (process) for forming the film will be described with reference to a schematic manufacturing process diagram shown in FIG.
In step S21, a chromium (Cr) 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 S22, a resist is applied to each of the metal films M to form a resist film R.
In step 23, the resist film R in portions corresponding to the lead electrodes 27a and 27b and the pad electrodes 29a and 29b is exposed using the mask pattern Mk for the lead electrodes and the pad electrodes.
In the next step S24, the exposed resist film R is developed and left, and the unexposed resist film R is peeled off. The metal film M exposed by the peeling is dissolved and removed with a solution such as aqua regia. The resist film R on the lead electrodes 27a and 27b and the pad electrodes 29a and 29b is left as it is.

In the next step S25, 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 laminated thereon to form a metal film M. Further, a resist film R is applied on the metal film M. In the figure of step S25, in order to avoid complication, a layer formed by combining the metal film M for the lead electrodes 27a and 27b and the pad electrodes 29a and 29b and the resist film R is represented by reference numeral C (M + R). . Then, using the mask pattern Mk for the excitation electrode, the resist film R in a portion corresponding to the excitation electrodes 25a and 25b is exposed.
In step S26, the exposed resist film R is developed and left, and the unexposed resist film R is peeled off using a solution.
In the next step S27, the resist film R is peeled off and the exposed metal film M is dissolved and removed with a solution such as aqua regia.
When the unnecessary resist film R remaining on the metal film M is peeled off, (Ni + Au) excitation electrodes 25a and 25b, (Cr + Au) lead electrodes 27a and 27b, and pad electrodes are formed on the front and back surfaces of each piezoelectric substrate 10. 29a and 29b are formed (step S28). After that, the support strips formed by half etching connected to the plurality of piezoelectric substrates 10 of the quartz wafer 10W are broken to obtain the piezoelectric vibration element 1 divided into individual pieces.

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 can be realized as the following aspect, and will be described in detail below.

19 and 20 are diagrams for explaining the recessed portions 11 and 11 ′ formed by etching on both surfaces of the quartz wafer 10W. FIG. 19A is a plan view of the crystal wafer 10W in step S5 of FIG. At this stage, the concave portions 11 and 11 ′ are regularly formed in a lattice shape on both surfaces of the quartz wafer 10W. FIG. 19B is a cut surface (cut) along the X-axis direction passing through the recessed portions 11 and 11 ′ of the quartz wafer 10W, and the recessed portion 11 on the upper side (front side) and the lower side of the quartz wafer 10W. Each wall surface of the recessed portion 11 ′ on the (back side) 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 X1, and the wall surface in the + X axis direction forms an inclined wall surface X2. Each inclined wall surface is etched symmetrically with respect to the X axis passing through the center of the vibrating portion 12 in the Y axis direction. 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. 19C to 19E are enlarged views of the inclined wall surfaces X1 and X2 of the recessed portions 11 and 11 ′ and the inclined 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 ′ is the inclined wall surface X1, and the wall surface in the + X axis direction is the inclined wall surface X2. 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 a line-symmetric relationship with respect to the X axis passing through the center of the vibrating portion 12 in the Y axis direction.
Both surfaces of the vibrating portion 12 formed by the bottom surface of the upper recessed portion 11 and the bottom surface of the lower recessed portion 11 ′ are etched substantially parallel to the plane before the crystal wafer 10W is etched. That is, the vibration part 12 becomes a flat plate shape whose front and back surfaces are substantially parallel.

FIG. 19D 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. 16, and the fourth thick portion main body 14a and the fourth inclined portion 14b are formed at the end portion in the −X axis direction (left direction in the drawing). A fourth thick portion 14 is formed, and a third thick portion comprising a third thick portion main body 15a and a third inclined portion 15b at the end in the + X-axis direction (right direction in the figure). 15 is formed. A slit 20 is formed in the surface of the third thick portion main body 15a.
FIG. 19E is a cross-sectional view of a groove (supporting strip) 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 inclined wall surface X3a of the upper groove portion of the piezoelectric substrate 10 is formed by the inclined wall surface X1 in the −X axis direction and the inclined wall surface X2 in the + X axis direction, and the inclined wall surface X3b of the lower groove portion is the center of the groove portion. On the other hand, since it is formed symmetrically with respect to the X axis passing through the upper inclined wall surface X3a and the center of the quartz wafer 10W in the Y axis direction (thickness direction), it is substantially wedge-shaped.
When providing an electrode 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 inclined wall surface X2. It is desirable to avoid the electrode film because it tends to tear.

  FIG. 20A is a plan view of the crystal wafer 10W in step S5 of FIG. FIG. 20B 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 vibrating portion 12. That is, the wall surface in the −Z′-axis direction of the lower recessed portion 11 ′ forms the inclined wall surface Z <b> 2, and the wall surface in the + Z′-axis direction forms the inclined wall surface Z <b> 1.

  FIGS. 20C to 20E are enlarged views of the inclined wall surfaces Z1 and Z2 of the upper and lower recessed portions 11 and 11 'and the inclined 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 direction in FIG. . The wall surface in the + Z′-axis direction exhibits an inclined wall surface Z2 as shown in the right direction in FIG. 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 inclined wall surfaces Z1 and Z2 along the Z′-axis direction of the lower concave portion 11 ′ are in a point-symmetric relationship with the upper concave portion 11 with respect to the center of the vibrating portion 12.

  FIG. 20D 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. An outer shape is formed in the etching step of step S9 in FIG. 16, and a first thickness consisting of a first thick portion main body 16a and a first inclined portion 16b at the end in the −Z′-axis direction (left direction in the figure). A thick portion 16 is formed, and a second thick portion 17 including a second thick portion main body 17a and a second inclined portion 17b is formed at an end portion in the + Z ′ axis direction (right direction in the drawing). The first thick part 16 and the second thick part 17 are formed substantially symmetrical with respect to the center of the vibration part 12.

FIG. 20E is a cross-sectional view of the upper and lower grooves formed orthogonal to the Z′-axis direction, and both present an inclined wall surface Z3 having a wedge-shaped cross section. The upper and lower grooves are grooves for folding the crystal wafer 10W. The inclined wall surface Z3 of the upper groove portion is formed by the inclined wall surface Z1 in the −Z′-axis direction of the recessed portion 11 and the inclined wall surface Z2 (the wall surface Z2a and the wall surface Z2b) in the + Z′-axis direction. Since the wall surface Z3 is formed point-symmetrically with the upper inclined wall surface Z3 with respect to the center of the groove portion, the wall surface Z3 has a substantially wedge-shaped cross section.
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.

The feature of this aspect is that etching is advanced from both main surfaces of the quartz wafer 10W, and concave portions 11 and 11 'that are opposed to the two main surfaces are formed as the vibrating portion 12, and the processing time required for etching is reduced. It became possible to halve. Another feature is that the piezoelectric substrate 10 can be reduced in size by removing both the outer sides of the broken lines Zc1 and Zc2 shown in FIG. 20D by etching. Since etching can proceed from both main surfaces of the piezoelectric substrate 10 and the etching depth from each main surface of the piezoelectric substrate 10 can be reduced, between the regions in which the individual pieces in the crystal wafer 10W are laid out at the time of manufacture Alternatively, the variation in thickness of the vibrating portion 12 that is thin between the quartz wafers 10W can be reduced.
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. The uniformity of the vibration portion may not be maintained, and variation in the thickness of the vibration part occurs between the areas where the individual pieces in the crystal wafer are laid out or between the crystal wafers, making it difficult to control the thickness. Because there is a problem.

Further, as shown in FIGS. 20C and 20D, a manufacturing method was established on the premise that both ends in the drawing unnecessary for the vibrating portion 12 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 portion. .
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 direction The frequency change amount when the force is applied to both ends in the Z′-axis direction can be reduced. Thereby, since the length of the piezoelectric substrate 10 in the X-axis direction is longer than the length in the Z′-axis direction, so-called X-long, it is possible to secure a large area of the vibrating portion 12 in the X-axis direction.
In addition, a thick part 13 is provided on at least one of the front and back surfaces of the main part of the vibration part 12 over the entire circumference of the vibration part 12 of the piezoelectric vibration element 1 of the present embodiment. Therefore, the end of the vibration part 12 is not exposed to the outside. As a result, the piezoelectric vibration caused by hitting the piezoelectric vibration element 1 against something in the process of manufacturing the piezoelectric vibration element 1 or mounting the piezoelectric vibration element 1 in a package (container) and manufacturing the piezoelectric vibrator. Also from the viewpoint of reliability such as the impact resistance of the element 1, the strength is kept high, so that the reliability can be kept high.
As a result, it becomes possible to design the displacement distribution of the thickness-shear vibration mode excited by the vibration part with sufficient consideration that it becomes an ellipse having 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.

21 is a detailed view of the piezoelectric vibration element 1 shown in FIG. 1, FIG. 21 (a) is a perspective view, and FIG. 21 (b) is a cross-sectional view taken along the line Q-Q in FIG. 'It is a sectional view seen from the axial direction. As shown in FIG. 21A, an inclined surface appears on the outer end surface that intersects the X axis of the piezoelectric vibration element 1. That is, as shown in FIG. 21B, the inclined surface 1 (inclined surfaces a1, a2) appears on the end surface on the −X axis side, and the inclined surface 2 (inclined surface b1) appears on the end surface on the + X axis side. , B2, b3, b4) appear. 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 10, the vertical wall surface of the inclined wall surface X2 formed in the + X axis direction as shown in FIGS. 19B and 19E is present. Not out. This is because the time required to form the inclined surfaces 1 (a1, a2) and the inclined surface 2 is determined by the outer shape of the piezoelectric substrate (quartz substrate) 10 compared to the etching time required to form the recessed portions 11, 11 ′. Since etching is performed until it penetrates, the etching time is sufficiently long, so that the vertical wall surface does not appear due to overetching.
The inclined surfaces a1 and a2 constituting the inclined surface 1 are substantially symmetrical with respect to the X axis, and the inclined surfaces b1, b2, b3 and b4 constituting the inclined surface 2 are inclined with respect to the inclined surfaces b1 and b4. It has been found that the surface b2 and the inclined surface b3 are 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.

  The piezoelectric vibration element 1 ′ of the embodiment shown in FIG. 22 is a modification of the piezoelectric vibration element 1 shown in FIG. 1, and is a part near the outer end of the third thick portion main body 15a. 3 has a structure in which the thickness of the thick portion main body 15a ′ is reduced by etching or the like. The reason for this is that when the pad electrode 29b formed on the third thick portion main body 15a ′ and the external electrode terminal are connected by the bonding wire BW, the apex portion in the + Y-axis direction of the bonding wire covers the package. This is to prevent contact with the member.

As shown in the embodiments of FIGS. 1, 5, 6, and 7, the high-frequency piezoelectric vibration element is downsized, and the thick-walled portion that supports the vibration portion is strong, and vibration, impact, etc. There is an effect that a strong piezoelectric vibration element 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.
In addition, when the portion that supports the piezoelectric vibration element becomes one point, it is possible to reduce the stress caused by the conductive adhesive.
Also, as shown in FIGS. 1, 5, and 6, there is an effect that the shock resistance and vibration resistance of the piezoelectric vibration element are enhanced by providing a thick portion at the end portion in contact with the vibration portion.

  As shown in the embodiment examples of FIGS. 8, 12, and 13, since the thick portion is reduced, the high-frequency piezoelectric vibration element using the fundamental wave can be reduced in size and the impact resistance can be enhanced. Mass production is possible. Furthermore, by forming at least one slit between the support portion and the vibration region, it is possible to suppress the spread of stress due to adhesion and fixation, so that the piezoelectric material has excellent frequency temperature characteristics, CI temperature characteristics, and frequency aging characteristics. There is an effect that a vibration element is obtained.

  9, the excitation electrodes 25a and 25b, the lead electrodes 27a and 27b, and the pad electrodes 29a and 29b are different metal materials, that is, the excitation electrodes 25a and 25b are nickel. The lead electrodes 27a and 27b and the pad electrodes 29a and 29b are formed of a chromium and gold laminated film. By doing so, there is an effect that a piezoelectric vibration element having a small CI value of the main vibration and a ratio of the CI value of the adjacent spurious to the CI value of the main vibration, that is, a large CI value ratio can be obtained.

  8, 12, and 13, the piezoelectric vibration element 1 includes the other main surface (back surface) of the vibration portion 12 and the other surface (back surface) of the first thick portion 16. Are on the same plane, and one main surface (surface) of the vibrating portion 12 and the other surface (surface) of the second thick portion 17 are formed on the same plane. For this reason, unnecessary thick portions are reduced, which is effective in reducing the size and improving the impact resistance. Further, the etching time is shortened by etching the piezoelectric substrate 10 from both the front and back surfaces to form the vibration region. Further, by eliminating the unnecessary thick portion, there is an effect that the miniaturization can be achieved and a high frequency fundamental wave piezoelectric vibration element having excellent frequency temperature characteristics can be obtained.

  Further, as shown in the embodiment examples of FIGS. 6 and 13, by providing two slits in the third thick portion 15, the spread of stress generated when the piezoelectric vibration element is bonded and fixed can be improved. Since suppression is possible, 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.

In addition, since the piezoelectric substrate 10 is formed as shown in the cutting angle diagram of FIG. 2, it is possible to configure the piezoelectric vibration element of the required specification with a more suitable cut angle and in accordance with the specification. There is an effect that a high-frequency piezoelectric vibration element having frequency temperature characteristics, a small CI value, and a large CI value ratio can be obtained.
In addition, by using a rotating Y-cut quartz substrate as a piezoelectric substrate, many years of experience and experience regarding photolithography 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 third thick portion 15 b increases in thickness as the third thick portion 15 moves away from one end edge connected to the vibrating portion 12 toward the other end edge. And the third thick portion main body 15a connected to the other end edge of the third inclined portion 15b, the piezoelectric vibration element of the fundamental wave at high frequency can be miniaturized. In addition, the support of the vibration part is strong, and there is an effect that a piezoelectric vibration element that is strong against vibration, impact and the like can be obtained.

[Vibrator]
(Form of vibrator 1)
FIG. 23 is a diagram showing a configuration of a piezoelectric vibrator as an embodiment of the vibrator according to the present invention, where FIG. 23 (a) is a longitudinal sectional view and FIG. 23 (b) is a plan view excluding a lid member. FIG. The piezoelectric vibrator 50 is, for example, the piezoelectric vibration element 4 of the fourth embodiment described above (in FIG. 23, an example using the piezoelectric vibration element 4 is shown, but the piezoelectric vibration element 4 according to another embodiment may be used. And a package for accommodating the piezoelectric vibration element 4. 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. 23, 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 4. 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 third thick portion main body 15a when the piezoelectric vibration element 4 is placed.
When the piezoelectric vibration element 4 is fixed to the package body 40, first, the conductive adhesive 30 is applied to the pad electrode 29 a of the piezoelectric vibration element 4, and this is reversed (inverted) and placed on the element mounting pad 47. Apply a load. As a characteristic of the conductive adhesive 30, the magnitude of stress (strain) due to the conductive 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 vibration element 4 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 that is inverted to 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. 23 (b), the portion for supporting and fixing the piezoelectric vibration element 4 to the package body 40 is one place (one point), that is, only one point of the conductive adhesive 30, and thus is generated by supporting and fixing. The magnitude of the stress can be reduced.
After the annealing treatment, the frequency is adjusted by adding mass to the excitation electrode 25b or reducing the mass. A lid member 49 is placed on the metal seal ring 44 formed on the upper surface of the package body 40, and the lid member 49 is sealed by seam welding in a vacuum or in an atmosphere of nitrogen N ₂ gas. 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 50.

  The piezoelectric vibrating element 4 is formed with pad electrodes 29a and 29b in proximity to the upper and lower surfaces of the piezoelectric substrate on which the piezoelectric vibrating element 4 is formed. When the piezoelectric vibration element 4 is accommodated in the package body 40, the piezoelectric vibration element 4 is turned over, and the pad electrode 29 a and the element mounting pad 47 of the package body 40 are fixed and connected by the conductive adhesive 30. The pad electrode 29b on the front surface side and the electrode terminal 48 of the package are connected by a bonding wire BW. Thus, when the site | part which supports the piezoelectric vibration element 4 becomes one point, it is possible to make small the stress resulting from the conductive adhesive 30. FIG. Further, when the piezoelectric vibration element 4 is turned upside down and accommodated in the package body 40 and the larger excitation electrode 25b is placed on the upper surface, fine adjustment of the frequency of the piezoelectric vibration element 4 is facilitated.

(Form of vibrator 2)
FIG. 24 is a longitudinal sectional view showing a configuration of a piezoelectric vibrator 50 ′ according to another embodiment of the vibrator. A difference from the embodiment shown in FIG. 23 is a method of supporting the piezoelectric vibration element 4. In the embodiment of FIG. 23, support is provided at one place, whereas in the embodiment of FIG. 24, conductive bonding is performed at two places (two points) of the third thick portion 15 on one surface of the piezoelectric vibration element 4. It is a structure in which the agent 30 is applied to achieve conduction, support and fixation. Although the structure is suitable for reducing the height, the stress caused by the conductive adhesive 30 may be slightly increased.

  Therefore, by adopting the piezoelectric vibrating elements 3, 7, 7 ′ provided with two slits as shown in FIGS. 6, 7, 13 and 14 as the third and sixth embodiments, It can be expected that the influence of stress on the vibration part can be suppressed. 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 embodiments of the piezoelectric vibrators 50 and 50 ′, an example in which a laminated plate is used for the package body 40 has been described. However, a cap using a single-layer ceramic plate for the package body 40 and the lid body being subjected to drawing processing. A piezoelectric vibrator may be configured by using.

  As described above, since the piezoelectric vibration element 4 shown in the above-described embodiment is used, the high-frequency piezoelectric vibrators 50 and 50 ′ are downsized and a piezoelectric vibrator having improved impact resistance is obtained. effective. Further, there is only one point for supporting the piezoelectric vibration element 4, and at least one slit 20 is formed between the supported portion (pad electrode 29 a) and the vibration portion 12, resulting in the conductive adhesive 30. The stress generated can be reduced. 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. In addition, a piezoelectric vibrator 50, 50 having a small CI value of the main vibration, a ratio of the CI value of the adjacent spurious to the CI value of the main vibration, that is, a large CI value ratio, and a small capacitance ratio γ is obtained. There is an effect that 'is obtained.

  Further, as shown in the embodiment of FIG. 24, by configuring a two-point supported piezoelectric vibrator, there is an effect that a piezoelectric vibrator 50 '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.

  Further, as shown in the embodiment examples of FIGS. 1 and 3 to 6, the electrode materials of the excitation electrodes 25 a and 25 b are made different from the electrode materials of the lead electrodes 27 a and 27 b and the pad electrodes 29 a and 29 b, In addition, since the piezoelectric vibration elements 1, 2, and 3 configured so that their film thicknesses are optimal for the respective functions are used, the CI value of the main vibration is small, and the CI value of the spurious adjacent to the CI value of the main vibration The piezoelectric vibration elements 1, 2, and 3 having a large CI ratio, that is, a large CI value ratio can be obtained.

[Piezoelectric devices as electronic devices]
FIG. 25 is a longitudinal sectional view showing an embodiment of an electronic device according to the present invention. A piezoelectric device 60 as an electronic device is one of the electronic components of the piezoelectric vibration element 1 of the first embodiment, the thermistor Th as a temperature sensor as a temperature sensor, the piezoelectric vibration element 1 and the thermistor. And a package for housing Th. In addition, although the example using the piezoelectric vibration element 1 was shown in this example, the piezoelectric vibration element shown in other embodiments may be used.

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. An element mounting pad 47 is provided at an end of the inner bottom surface of the cavity 31, and the element mounting pad 47 is electrically connected to the plurality of mounting terminals 45 by a conductor 46 disposed inside the package body 40 a.
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. The pad electrode 29b that is reversed and becomes the surface side is connected to the electrode terminal 48 by a bonding wire BW. A metal seal 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 metal seal 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. The terminal of the thermistor Th is connected to the electronic component mounting pad 33 in the concave portion 32 on the back surface using a solder ball or the like to complete the piezoelectric device 60.

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 main body 40a was demonstrated, as an electronic component accommodated in the package main body 40a, at least one of a thermistor, a capacitor | condenser, a reactance element, and a semiconductor element is included. It is desirable to configure the electronic device by accommodating the.

The embodiment shown in FIG. 25 is an example in which the piezoelectric vibration element 1 and the thermistor Th are accommodated in the package body 40a. With this configuration, since the thermistor Th of the temperature sensitive element is located 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. In addition, by configuring an electronic device (piezoelectric device) with the piezoelectric vibration element according to the present invention and the above-described electronic component, a high-frequency and small-sized electronic device (piezoelectric device) can be configured. There is an effect that can be done.
In addition, when an electronic device (piezoelectric device) is configured by 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. There is an effect.

  FIG. 26 is a diagram showing a configuration of a piezoelectric oscillator 70 which is a kind of electronic device according to an embodiment of the present invention, where FIG. 26 (a) is a longitudinal sectional view and FIG. 26 (b) is a lid member. FIG. The piezoelectric oscillator 70 includes a package main body 40b, a lid member 49, the piezoelectric vibration element 1 according to the first embodiment, an IC component 51 on which an oscillation circuit for exciting the piezoelectric vibration element 1 is mounted, and a capacitance that varies depending on voltage. And at least one of electronic components 52 such as a variable capacitance element, a thermistor whose resistance changes with temperature, and an inductor. In addition, although the example which used the piezoelectric vibration element 1 was shown in this example, the piezoelectric vibration element shown in other embodiment may be sufficient.

A conductive adhesive (polyimide) 30 is applied to the pad electrode 29a of the piezoelectric vibration element 1, and this is reversed and placed on the element mounting pad 47a of the package body 40b, and the pad electrode 29a and the element mounting pad 47a are Ensuring continuity. The pad electrode 29b that is inverted and turned to the upper surface side and the other electrode terminal 48 of the package body 40b are connected by the bonding wire BW to achieve conduction. The IC component 51 is fixed to a predetermined position of 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. Further, the electronic component 52 is placed at a predetermined position of the package body 40b and connected using metal bumps or the like. The package body 40 b is filled with an inert gas such as vacuum or nitrogen, and the package body 40 b is sealed with a lid member 49 to complete the piezoelectric oscillator 70.
In the method of connecting the pad electrode 29b and the electrode terminal 48 of the package with the bonding wire BW, the portion supporting the piezoelectric vibration element 1 becomes one point, and the stress caused by the conductive adhesive 30 can be reduced. It is. Further, since the piezoelectric vibrating element 1 is turned over (inverted) and the larger excitation electrode 25b is placed on the upper surface when housed in the package body 40b, frequency fine adjustment of the piezoelectric oscillator 70 as an electronic device is facilitated.

In the piezoelectric oscillator 70 shown in FIG. 26, the piezoelectric vibration element 1, the IC component 51, and the electronic component 52 are arranged on the inner bottom surface of the same package body 40b. However, the piezoelectric oscillator 70 ′ of the embodiment shown in FIG. Uses an H-shaped package main body 40 a, and the piezoelectric vibration element 1 is accommodated in a cavity 31 formed in the upper portion, and the cavity 31 is filled with vacuum or nitrogen N ₂ gas and sealed with a lid member 61. In the lower part, an IC component 51 on which an oscillation circuit, an amplifier 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 necessary are provided with metal bumps ( Through the (Au bumps) 68, they are conducted and connected to the terminals 67 of the package body 40a.
The electronic device (piezoelectric oscillator) 70 ′ of the present embodiment separates the piezoelectric vibration element 1 from the IC component 51 and the electronic component 52, and the piezoelectric vibration element 1 is hermetically sealed alone. Excellent frequency aging of 70.

By configuring piezoelectric oscillators 70 and 70 ′ (for example, voltage controlled piezoelectric oscillators) which are a kind of electronic devices as shown in FIGS. 26 and 27, the frequency reproducibility, frequency temperature characteristics, and aging characteristics are excellent, and the size is small. In addition, there is an effect that a voltage controlled piezoelectric oscillator having a high frequency (for example, 490 MHz band) can be obtained. Further, since the piezoelectric oscillators 70 and 70 'use 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 S / N ratio is good. There is an effect that a voltage controlled piezoelectric oscillator can be obtained.
In addition, it is possible to configure piezoelectric oscillators, temperature compensated piezoelectric oscillators, voltage controlled piezoelectric oscillators, etc. as electronic devices, piezoelectric oscillators with excellent frequency reproducibility and aging characteristics, and 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).

[Electronics]
FIG. 28 is a schematic configuration diagram showing a configuration of an electronic apparatus according to an embodiment of the present invention. The electronic device 8 includes the above-described piezoelectric vibrators 50 and 50 ′. Examples of the electronic device 8 using the piezoelectric vibrator 50 include a transmission device. In these electronic devices 8, the piezoelectric vibrators 50, 50 ′ are used as a reference signal source, a voltage variable piezoelectric oscillator (VCXO), or the like, and can provide a small electronic device with good characteristics.
By using the piezoelectric vibrator according to 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.

  Next, an electronic device to which the resonator element according to an embodiment of the invention is applied will be described in detail with reference to FIGS.

  FIG. 29 is a schematic perspective view illustrating a configuration of a mobile (or notebook) personal computer as an electronic apparatus including the resonator element according to the embodiment of the invention. In this figure, a personal computer 1100 includes a main body portion 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display portion 100. The display unit 1106 is rotated with respect to the main body portion 1104 via a hinge structure portion. It is supported movably. Such a personal computer 1100 incorporates a vibration element 1 that functions as a filter, a resonator, a reference clock, and the like.

  FIG. 30 is a schematic perspective view illustrating a configuration of a mobile phone (including PHS) as an electronic apparatus including the resonator element according to an embodiment of the invention. In this figure, a cellular phone 1200 includes a plurality of operation buttons 1202, an earpiece 1204, and a mouthpiece 1206, and the display unit 100 is disposed between the operation buttons 1202 and the earpiece 1204. Such a cellular phone 1200 incorporates the vibration element 1 that functions as a filter, a resonator, or the like.

FIG. 31 is a schematic perspective view illustrating a configuration of a digital camera as an electronic apparatus including the resonator element according to an embodiment of the invention. In this figure, connection with an external device is also simply shown. Here, a normal camera sensitizes a silver salt photographic film with a light image of a subject, whereas a digital camera 1300 captures a light image of a subject by photoelectrically converting it with an image sensor such as a CCD (Charge Coupled Device). A signal (image signal) is generated.
A display unit 100 is provided on the back surface of a case (body) 1302 in the digital camera 1300, and is configured to perform display based on an imaging signal from the CCD. The display unit 100 displays a subject as an electronic image. Function as. A light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided on the front side (the back side in the drawing) of the case 1302.
When the photographer confirms the subject image displayed on the display unit 100 and presses the shutter button 1306, the CCD image pickup signal at that time is transferred and stored in the memory 1308. In the digital camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side surface of the case 1302. As shown in the figure, a television monitor 1430 is connected to the video signal output terminal 1312 and a personal computer (PC) 1440 is connected to the input / output terminal 1314 for data communication as necessary. Further, the imaging signal stored in the memory 1308 is output to the television monitor 1430 or the personal computer 1440 by a predetermined operation. Such a digital camera 1300 incorporates a vibration element 1 that functions as a filter, a resonator, or the like.

  The electronic device including the vibration element according to the embodiment of the present invention includes, for example, an ink jet type in addition to the personal computer (mobile personal computer) in FIG. 29, the mobile phone in FIG. 30, and the digital camera in FIG. Discharge device (for example, inkjet printer), laptop personal computer, TV, video camera, video tape recorder, car navigation device, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic game device, word processor, Workstations, videophones, crime prevention TV monitors, electronic binoculars, POS terminals, medical equipment (for example, electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasonic diagnostic devices, electronic endoscopes), fish detectors, various types Measuring equipment, instruments (eg cars , Aircraft, gauges of a ship), can be applied to a flight simulator or the like.

[Moving object]
FIG. 32 is a perspective view schematically showing an automobile as an example of a moving body. The automobile 106 is equipped with a vibrator or an electronic device having the above-described vibration element. For example, keyless entry, immobilizer, car navigation system, car air conditioner, anti-lock brake system (ABS), air bag, tire pressure monitoring system (TPMS), engine control, hybrid car and electric car It can be widely applied to electronic control units (ECUs) such as battery monitors and vehicle body posture control systems.

[Modified Embodiment: Part 1]
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 FIG. 33A includes a thin portion having the vibrating portion 12 and a thick portion 13 that is provided on the periphery of the thin portion and is thicker than the thin portion. In one thick part of the thick part 13, a slit 20 is provided along the vibration part 12, and the mount part F is connected side by side through the buffer part S in the direction of the edge. The mount portion F has chamfered portions 21 at both ends in a direction orthogonal to the direction in which the mount portion F, the buffer portion S, and the thick portion 13 are arranged.

  The piezoelectric substrate 10 of FIG. 33B includes a thin portion having the vibrating portion 12 and a thick portion 13 provided on the periphery of the thin portion and thicker than the thin portion. In one thick part of the thick part 13, a slit 20 is provided along the vibration part 12, and the mount part F is connected side by side through the buffer part S in the direction of the edge. The mount portion F has notches 22 at both ends in a direction orthogonal to the direction in which the mount portion F, the buffer portion S, and the thick portion 13 are arranged. The longitudinal direction of the slit 20 is substantially parallel to the orthogonal direction, and the width of the mounting part F in the orthogonal direction is formed to be narrower than the longitudinal direction width of the slit 20. Furthermore, both end portions in the longitudinal direction of the slit 20 are closer to the outer periphery in the orthogonal direction than both end portions of the mount portion F.

  The piezoelectric substrate 10 shown in FIG. 33C includes a thin portion having the vibrating portion 12 and a thick portion 13 that is provided on the periphery of the thin portion and is thicker than the thin portion. One thick portion of the thick portion 13 is provided with a slit 20 along the vibrating portion 12, and the buffer portion S and the mount portion F are connected side by side in the direction of the edge. The mount portion F has notches 22 at both ends in a direction orthogonal to the direction in which the mount portion F, the buffer portion S, and the thick portion 13 are arranged. The thick portion where the slit 20 and the buffer portion S are provided has an end portion orthogonal to the direction in which the mount portion F and the buffer portion S are aligned, and the end portion of the vibrating portion 12 and the thick portion. It protrudes from the end of the other thick part provided in the direction orthogonal to the extending direction.

FIG. 34 is characterized in that the structure of FIG. 33 is in the form of two-point support, that is, in the form of a mount part F1 and a mount part F2 instead of the mount part F.
In FIGS. 33 and 34, there is an inclined portion on the inner wall of each thick portion of the thick portion 13 (the first thick portion 16, the third thick portion 15, and the fourth thick portion 14). On the other hand, the inclined wall as shown in FIG. 21 is not shown on the outer side wall surface of the thick portion 13, but these inclined portions and inclined surfaces are as shown in FIG. It will be formed at the corresponding site.
In addition, each code | symbol in FIG. 33, FIG. 34 respond | corresponds with the site | part which the same code | symbol of said each embodiment shows.

[Modified Embodiment: Part 2]
FIG. 35 is a modified example of the piezoelectric vibration element 1. FIG. 35A is a plan view, and FIG. 35B is an enlarged plan view of the pad electrode 29 a (mount portion F) of the piezoelectric vibration element 1. FIG. 3C shows a cross-sectional view of the mount portion F. In the mount portion F, the area to be bonded is expanded by making the surface uneven to improve the adhesive strength.

  DESCRIPTION OF SYMBOLS 1,1 ', 2,3,4,6,7 ... Piezoelectric vibration element, 8 ... Electronic device, 10 ... Piezoelectric substrate, 10W ... Quartz wafer, 11, 11' ... Recessed part, 12 ... Vibration part, 12a, 12b , 12c, 12d ... one side of the vibration part, 13 ... thick part, 14 ... fourth thick part, 14a ... fourth thick part body, 14b ... fourth inclined part, 15 ... third thick part 15a ... third thick part main body, 15b ... third inclined part, 15b ', 15bb ... extremely slanted part, 16 ... first thick part, 16a ... first thick part main body, 16b ... 1st inclined part, 17 ... 2nd thick part, 17a ... 2nd thick part main body, 17b ... 2nd inclined part, 20 ... slit, 20a ... 1st slit, 20b ... 2nd Slit, 21 ... chamfered portion, 22 ... notched portion, 25a, 25b ... excitation electrode, 27a, 27b ... lead electrode, 29a, 29b ... 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 ... metal seal ring, 45 ... mounting terminal, 46 ... conductor, 47 ... element mounting pad, 48 ... electrode terminal, 49 ... lid member, 50, 50 '... piezoelectric vibrator, 51 ... IC component , 52 electronic components, 55 ... electrode terminals, 60, 70 ... piezoelectric devices, 61 ... lid members, 65 ... mounting terminals, 66 ... conductors, 67 ... component terminals, 68 ... metal bumps (Au bumps), Th ... thermistors, F, F1, F2 ... mount part, S ... buffer part.

Claims (20)

A vibrating part;
A first thick portion provided integrally with the vibrating portion along a first outer edge of the vibrating portion, and having a thickness greater than the vibrating portion;
A substrate including a second thick portion provided integrally with the vibrating portion along a second outer edge of the vibrating portion facing the first outer edge, and having a thickness greater than the vibrating portion;
The first thick part is provided to protrude from one main surface of the vibration part,
The vibration element according to claim 1, wherein the second thick portion is provided so as to protrude from a main surface on the back side with respect to one main surface of the vibration portion. In claim 1,
Along with the third outer edge of the vibration part connecting between one end of each of the first outer edge and the second outer edge, the thickness is larger than the vibration part integrally with the vibration part. A vibration element characterized in that a thick third portion is provided. In claim 2,
Along with the fourth outer edge of the vibrating part connecting the other end of each of the first outer edge and the second outer edge, the thickness of the vibrating part is integrated with the vibrating part. A vibration element, characterized in that a thick fourth portion is provided. In any one of Claims 1 thru | or 3,
The vibrating element according to claim 1, wherein the substrate is a rotating Y-cut quartz substrate. In claim 4,
The vibration element according to claim 3, wherein the third thick part is on the + X axis side in a plan view with respect to the vibration part. In claim 5,
The vibration element according to claim 4, wherein the fourth thick part is on the −X axis side in a plan view with respect to the vibration part. In claim 5 or 6,
The third thick part is an inclined part that increases in thickness as it is separated from one end edge connected to the vibration part toward the other end edge;
A vibration element comprising: a thick portion main body provided continuously with the other edge of the inclined portion. In claim 7,
The vibration element, wherein the third thick part is provided with at least one slit. In claim 8,
The vibration element according to claim 1, wherein the slit is provided in the thick portion main body along a boundary portion between the inclined portion and the thick portion main body. In claim 8,
The vibration element according to claim 1, wherein the slit is disposed in the inclined portion so as to be separated from the third outer edge of the vibration portion. In claim 8,
The slit is
A first slit disposed in the thick part body;
And a second slit disposed in the inclined portion so as to be separated from the third outer edge of the vibration portion. In claim 11,
The first slit is
The vibration element is arranged in the thick part main body along the boundary part between the inclined part and the thick part main body. The vibration element according to any one of claims 1 to 3,
And a package for housing the vibration element. The vibration element according to any one of claims 1 to 3,
An electronic device comprising an electronic component and a package. In claim 14,
The electronic device is at least one of a variable capacitance element, a thermistor, an inductor, and a capacitor. The vibration element according to any one of claims 1 to 3,
An electronic device comprising: an oscillation circuit that excites the vibration element; and a package.   An electronic device comprising the vibration element according to claim 1.   An electronic apparatus comprising the electronic device according to claim 16.   A moving body comprising the vibration element according to claim 1. The vibration part is provided integrally with the vibration part along the first outer edge and the second outer edge of the vibration part facing each other, protrudes from one main surface of the vibration part, and is thicker than the vibration part. A vibration element manufacturing method comprising: a thick first thick portion; and a second thick portion that protrudes from a main surface on the back side with respect to one main surface of the vibration portion and is thicker than the vibration portion. And
Preparing a substrate;
A thick part forming step of forming the first thick part and the second thick part by etching the substrate;
A vibrating element outer shape forming step of forming an outer shape of the vibrating element by etching the substrate;
And an electrode forming step of forming an electrode on the vibration element.

Images