Vibration element, vibrator and oscillator

Abstract

To provide a high-frequency, low-CI-value vibration element, vibrator, and oscillator.SOLUTION: A vibration element 1 comprises a crystal substrate 10 having a vibration portion 11 containing a vibration region 13 and a support portion 12 with a thickness greater than that of the vibration portion 11, and excitation electrodes 31, 32 positioned in the vibration region 13, and when the thickness variation y[nm] in the vibration region 13 of the crystal substrate 10 is taken as the variable and the oscillation frequency x[MHz] is taken as the variable, the relationship y≤329.8exp(-x / 76.7)+4.0 is satisfied.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a vibration element, a vibrator, and an oscillator. [Background technology]

[0002] Patent Document 1 discloses a vibration element that has the objective of realizing a small, high-frequency piezoelectric vibration element with a small CI value and suppressing nearby spurious signals at the fundamental wave, and that includes a rectangular vibration part, an L-shaped thick part formed integrally with the vibration part, and a slit arranged in the thick part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-7693 Summary of the Invention [Problem to be solved by the invention]

[0004] Communications devices are being required to achieve higher speeds and larger capacity communications, and the demand for higher frequencies is also increasing for vibration elements. However, as frequencies increase, the CI value tends to increase, and there are increasing cases where the required performance of oscillators cannot be met. Therefore, there are limits to achieving higher frequencies and lower CI values ​​simply by devising the arrangement of the vibrating part and thick part, as in the piezoelectric vibration element of Patent Document 1. [Means for solving the problem]

[0005] The vibration element comprises a quartz substrate having a vibration part including a vibration region and a support part that is thicker than the vibration part, and an excitation electrode arranged in the vibration region, and satisfies the relationship y≦329.8exp(-x / 76.7)+4.0, where y [nm] is the thickness variation in the vibration region of the quartz substrate and x [MHz] is the oscillation frequency.

[0006] The vibrator includes the above-described vibration element and a container that houses the vibration element.

[0007] The oscillator includes the above-described vibration element, an oscillation circuit that excites the vibration element, and a container that houses the vibration element and the oscillation circuit. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a configuration of a vibration element according to a first embodiment. [Figure 2] 1 is a diagram illustrating the relationship between an AT-cut quartz crystal substrate and the crystal axes of quartz crystal. [Figure 3] FIG. 2 is a plan view of the vibration element shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line A1-A1 in FIG. 3. [Figure 5] FIG. 10 is a diagram showing the relationship between oscillation frequency and thickness variation in the vibration region. [Figure 6] FIG. 10 is a plan view showing the configuration of a vibration element according to a second embodiment. [Figure 7] FIG. 7 is a cross-sectional view taken along line A2-A2 in FIG. [Figure 8] FIG. 10 is a plan view showing the configuration of a vibration element according to a third embodiment. [Figure 9] FIG. 9 is a cross-sectional view taken along line A3-A3 in FIG. 8. [Figure 10] FIG. 10 is a plan view showing the configuration of a vibration element according to a fourth embodiment. [Figure 11] FIG. 11 is a cross-sectional view taken along line A4-A4 in FIG. [Figure 12] FIG. 10 is a plan view showing the configuration of a vibration element according to a fifth embodiment. [Figure 13] 13 is a cross-sectional view taken along line A5-A5 in FIG. 12. [Figure 14] FIG. 10 is a plan view showing the configuration of a vibration element according to a sixth embodiment. [Figure 15] 15 is a cross-sectional view taken along line A6-A6 in FIG. 14. [Figure 16] FIG. 13 is a plan view showing the configuration of a vibrator according to a seventh embodiment. [Figure 17] 17 is a cross-sectional view taken along line A7-A7 in FIG. 16. [Figure 18]FIG. 13 is a plan view showing the configuration of an oscillator according to an eighth embodiment. [Figure 19] 19 is a cross-sectional view taken along line A8-A8 in FIG. 18. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1. First embodiment A vibration element 1 according to a first embodiment will be described with reference to FIGS.

[0010] For ease of explanation, in each of the subsequent figures except for Figures 2, 5, 18, and 19, three mutually orthogonal axes are illustrated as the X-axis, Y'-axis, and Z'-axis. The longitudinal direction of the vibration element 1 is referred to as the "X-direction" along the X-axis, the thickness direction of the vibration element 1 is referred to as the "Y'-direction" along the Y'-axis, and the direction perpendicular to the X-axis and Y'-axis is referred to as the "Z'-direction" along the Z'-axis. The arrow side of each axis is referred to as the "plus side," and the opposite side of the arrow is referred to as the "minus side."

[0011] As shown in Figure 1, the vibration element 1 of this embodiment comprises a quartz crystal substrate 10 having a vibration portion 11 including a vibration region 13 and a support portion 12 that is thicker than the vibration portion 11, and excitation electrodes 31 and 32 arranged in the vibration region 13.

[0012] The quartz crystal substrate 10 is a plate-shaped substrate. The quartz crystal used for the quartz crystal substrate 10 belongs to the trigonal crystal system and has mutually orthogonal crystal axes X, Y, and Z, as shown in FIG. 2. The X, Y, and Z axes are referred to as the electrical, mechanical, and optical axes, respectively. The quartz crystal substrate 10 of this embodiment is a "rotated Y-cut quartz crystal substrate" cut along a plane obtained by rotating the XZ plane by a predetermined angle θ around the X axis. For example, a substrate cut along a plane rotated by θ = 35°15' is called an "AT-cut quartz crystal substrate." Using such a quartz crystal substrate 10 results in a vibrating element 1 with excellent temperature characteristics.

[0013] However, the quartz crystal substrate 10 is not limited to an AT-cut quartz crystal substrate, and may be, for example, a BT-cut quartz crystal substrate, as long as it can excite thickness-shear vibration. In the following description, the Y and Z axes rotated around the X axis by the angle θ are referred to as the Y' and Z' axes. That is, the quartz crystal substrate 10 has a thickness in the Y' direction and an extent in the XZ' plane direction.

[0014] The quartz crystal substrate 10 has a longitudinal shape with its long side in the X direction and its short side in the Z' direction in plan view. The quartz crystal substrate 10 has its tip end in the minus X direction and its base end in the plus X direction.

[0015] As shown in Figures 1 and 3, the quartz substrate 10 comprises a vibrating portion 11 including a vibrating region 13, which is an area where vibration energy is trapped, and a supporting portion 12 that is integrated with the vibrating portion 11 and is thicker than the vibrating portion 11.

[0016] The vibrating portion 11 is biased toward the negative side in the X direction and the negative side in the Z' direction with respect to the center of the quartz substrate 10, and part of its outer edge is exposed from the support portion 12. In other words, part of the outer edge of the vibrating portion 11 forms part of the outer edge of the quartz substrate 10. In a plan view of the vibrating element 1, the area of ​​the vibrating portion 11 is preferably equal to or less than half the area of ​​the quartz substrate 10. This allows the support portion 12, which has high mechanical strength, to be formed sufficiently wide, thereby ensuring sufficient rigidity of the vibrating portion 11.

[0017] The support part 12 protrudes beyond the vibrating part 11 on the side of one surface 14 of the vibrating part 11. Specifically, as shown in Figures 1, 3, and 4, the main surface of the support part 12 on the positive side in the Y' direction is provided to protrude toward the positive side in the Y' direction beyond one surface 14, which is the main surface of the vibrating part 11 on the positive side in the Y' direction. On the other hand, the main surface of the support part 12 on the negative side in the Y' direction is provided on the same plane as the other surface 15, which is the main surface of the vibrating part 11 on the negative side in the Y' direction.

[0018] The support portion 12 has a support portion 12 that connects to the outer edge of the vibrating portion 11 on the positive side in the X direction, and a support portion 12 that connects to the outer edge of the vibrating portion 11 on the positive side in the Z' direction. Therefore, the support portion 12 has a structure that is bent along the vibrating portion 11 in a plan view, and is substantially L-shaped. Therefore, it is possible to reduce the mass of the tip side of the vibrating element 1 while maintaining the rigidity of the vibrating portion 11 of the vibrating element 1. It is also possible to reduce the size of the vibrating element 1.

[0019] Supporting section 12 is provided with: connecting section 16, which connects supporting section 12 and vibrating section 11; connecting section 16 is connected to the outer edge of vibrating section 11 on the positive side in the Z' direction and has a sloped section whose thickness gradually increases in the positive Z' direction; and connecting section 17 is connected to the outer edge of vibrating section 11 on the positive side in the X direction and has a sloped section whose thickness gradually increases in the positive X direction. In addition, supporting section 12 on the connecting section 17 side serves as a mount, and is fixed to a container or the like using a conductive adhesive or the like.

[0020] On the quartz crystal substrate 10, a pair of excitation electrodes 31 and 32, a pair of pad electrodes 33 and 34, and a pair of extraction electrodes 35 and 36 are formed.

[0021] The excitation electrodes 31 and 32 are arranged in the vibration region 13 of the vibration part 11. The excitation electrode 31 is arranged on one surface 14 of the vibration part 11. On the other hand, the excitation electrode 32 is arranged on the other surface 15 of the vibration part 11 so as to face the excitation electrode 31. The excitation electrodes 31 and 32 are each a substantially rectangular shape with the long side extending in the X direction and the short side extending in the Z' direction.

[0022] The pad electrodes 33 and 34 are arranged at the base end of the support part 12 on the connection part 17 side. The pad electrode 33 is arranged on one surface 14 side of the vibrating part 11. On the other hand, the pad electrode 34 is arranged on the other surface 15 side of the vibrating part 11 so as to face the pad electrode 33.

[0023] The extraction electrodes 35 and 36 are arranged on the vibrating part 11 and the support part 12. The extraction electrode 35 electrically connects the excitation electrode 31 and the pad electrode 33. On the other hand, the extraction electrode 36 electrically connects the excitation electrode 32 and the pad electrode 34. The extraction electrodes 35 and 36 are arranged so as not to overlap with each other via the quartz substrate 10. This makes it possible to reduce the electrostatic capacitance between the extraction electrodes 35 and 36.

[0024] Next, the relationship between the oscillation frequency of the vibration element 1 and the thickness variation of the vibration region 13 in order to achieve a higher frequency and a lower CI value will be described with reference to FIG. FIG. 5 is a graph plotting the actual measurements of the thickness variation of the vibration region 13 where the CI value satisfies the specified value for the oscillation frequency of the vibration element 1, and shows an approximation curve Y calculated from the three plots by the least squares method.

[0025] The approximate curve Y satisfies the relationship y≦329.8exp(−x / 76.7)+4.0, where y [nm] is the thickness variation in the vibration region 13 of the quartz substrate 10 and x [MHz] is the oscillation frequency. The thickness of the vibration region 13 of the quartz substrate 10 was measured using a spectroscopic interferometric laser displacement meter in the area where the excitation electrodes 31 and 32 are arranged at a pitch of 1.6 μm, and the standard deviation Σ of the measured values ​​was used to determine the thickness.

[0026] As can be seen from FIG. 5, the vibration element 1 having a low CI value can be obtained by setting the thickness variation in the vibration region 13 to the value of the approximation curve Y at each oscillation frequency.

[0027] Furthermore, if the thickness variation in the vibration region 13 is set to 12 nm or less, it is possible to obtain a vibration element 1 having a low CI value at an oscillation frequency of 285 MHz or less.

[0028] Furthermore, if the thickness variation in the vibration region 13 is set to 5 nm or less, it is possible to obtain a vibration element 1 having a low CI value at an oscillation frequency of 492 MHz or less.

[0029] Furthermore, if the thickness variation in the vibration region 13 is set to 4 nm or less, it is possible to obtain a vibration element 1 having a low CI value at an oscillation frequency of 700 MHz or less.

[0030] That is, the vibration element 1 having a low CI value can be obtained by making the thickness variation in the vibration region 13 equal to or less than the value of the approximation curve Y at each oscillation frequency.

[0031] As described above, the resonator element 1 of this embodiment satisfies the relationship y≦329.8exp(−x / 76.7)+4.0, where y [nm] is the thickness variation in the resonating region 13 of the quartz substrate 10 and x [MHz] is the oscillation frequency, and therefore can achieve a low CI value even at high frequencies. Therefore, it can meet the performance requirements of oscillators used in communication devices for high-speed, large-capacity communication.

[0032] 2. Second embodiment Next, a vibration element 1a according to a second embodiment will be described with reference to FIGS.

[0033] The vibration element 1a of this embodiment is similar to the vibration element 1 of the first embodiment except that the structure of the quartz substrate 10a is different from that of the vibration element 1 of the first embodiment. The following description will focus on the differences from the first embodiment described above, and similar items will be denoted by the same reference numerals and their description will be omitted.

[0034] As shown in Figures 6 and 7, the vibration element 1a comprises a quartz crystal substrate 10a having a vibration portion 11 including a vibration region 13 and a support portion 12a that is thicker than the vibration portion 11, and excitation electrodes 31 and 32 arranged in the vibration region 13.

[0035] Support portion 12a protrudes from vibrating portion 11 on one surface 14 side of vibrating portion 11, and also protrudes from vibrating portion 11 on the other surface 15 side, which is the back side of one surface 14. In other words, since vibrating portion 11 is formed by etching vibrating portion 11 from both one surface 14 and the other surface 15, the amount of etching on one surface can be reduced, and vibrating element 1a with small plate thickness variations in vibrating region 13 can be obtained.

[0036] Support portion 12a is provided with: connecting portion 16a, which connects support portion 12a and vibration portion 11; connecting portion 16a connected to the outer edge of vibration portion 11 on the positive side of the Z' direction and having an inclined portion whose thickness gradually increases in the positive Z' direction; connecting portion 17a connected to the outer edge of vibration portion 11 on the positive X direction and having an inclined portion whose thickness gradually increases in the positive X direction; and connecting portion 18a connected to the outer edge of vibration portion 11 on the negative Z' direction and having an inclined portion whose thickness gradually increases in the negative Z' direction.

[0037] The vibrating part 11 is connected to the support part 12a at its outer edge on the positive side in the X direction, its outer edge on the positive side in the Z' direction, and its outer edge on the negative side in the Z' direction, which is part of the outer edge of the vibrating part 11, forms part of the outer edge of the quartz crystal substrate 10a. This further improves the rigidity of the vibrating part 11 of the vibrating element 1a.

[0038] In this embodiment, the support parts 12a are connected to the three outer edges of the vibration part 11, but as in the first embodiment, the support parts 12a may be connected to two outer edges of the vibration part 11.

[0039] With this configuration, the vibration element 1a has a low CI value at high frequencies, the thickness variation of the vibration region 13 can be reduced, and the vibration element 1a with the vibration part 11 having improved rigidity can be obtained.

[0040] 3. Third embodiment Next, a vibration element 1b according to a third embodiment will be described with reference to FIGS.

[0041] The vibration element 1b of this embodiment is similar to the vibration element 1 of the first embodiment except that the structure of the quartz crystal substrate 10b is different from that of the vibration element 1 of the first embodiment. The following description will focus on the differences from the first embodiment described above, and similar items will be denoted by the same reference numerals and their description will be omitted.

[0042] As shown in Figures 8 and 9, the vibration element 1b comprises a quartz crystal substrate 10b having a vibration portion 11 including a vibration region 13 and a support portion 12b that is thicker than the vibration portion 11, and excitation electrodes 31 and 32 arranged in the vibration region 13.

[0043] The support portion 12b includes a first support portion 121 arranged along one outer edge of the vibrating portion 11, which is the outer edge on the plus Z' side, and a second support portion 122 arranged along the other outer edge, which is the minus Z' side, opposite to the one outer edge of the vibrating portion 11, the first support portion 121 protruding from one surface 14 side of the vibrating portion 11, and the second support portion 122 protruding from the vibrating portion 11 on the other surface 15 side behind the one surface 14. In other words, since the vibrating portion 11 is formed by etching from both sides, the amount of etching on one surface can be reduced, and a vibrating element 1b with small plate thickness variations in the vibrating region 13 can be obtained.

[0044] The first support portion 121 and the vibrating portion 11 are connected by a connecting portion 16b that is connected to the outer edge 111 on the positive side of the Z' direction of the vibrating portion 11 and has an inclined portion whose thickness gradually increases in the positive Z' direction. The support portion 12b and the vibrating portion 11 are connected by a connecting portion 17b that is connected to the outer edge of the vibrating portion 11 on the positive side of the X direction and has an inclined portion whose thickness gradually increases in the positive X direction. The second support portion 122 and the vibrating portion 11 are connected by a connecting portion 18b that is connected to the outer edge 112 on the negative side of the Z' direction of the vibrating portion 11 and has an inclined portion whose thickness gradually increases in the negative Z' direction. This allows the vibration region 13 of the vibrating portion 11 to be widened.

[0045] Only the outer edge of the vibrating part 11 on the negative side in the X direction, which is part of the outer edge of the vibrating part 11, forms part of the outer edge of the quartz crystal substrate 10b, which further improves the rigidity of the vibrating part 11 of the vibrating element 1b.

[0046] By adopting such a configuration, the vibration element 1b has a low CI value at high frequencies, the thickness variation of the vibration region 13 can be reduced, the vibration region 13 of the vibration part 11 can be widened, and a vibration element 1b with improved rigidity of the vibration part 11 can be obtained.

[0047] 4. Fourth embodiment Next, a vibration element 1c according to a fourth embodiment will be described with reference to FIGS.

[0048] The vibration element 1c of this embodiment is similar to the vibration element 1 of the first embodiment except that the structure of the quartz crystal substrate 10c is different from that of the vibration element 1 of the first embodiment. The following description will focus on the differences from the first embodiment described above, and similar items will be denoted by the same reference numerals and their description will be omitted.

[0049] As shown in Figures 10 and 11, the vibration element 1c comprises a quartz crystal substrate 10c having a vibration portion 11 including a vibration region 13 and a support portion 12c that is thicker than the vibration portion 11, and excitation electrodes 31 and 32 arranged in the vibration region 13.

[0050] The support portion 12c protrudes from the vibrating portion 11 on the side of one surface 14 of the vibrating portion 11. In addition, support portion 12c is provided with: connection portion 16c, which connects support portion 12c and vibration portion 11; connection portion 16c, which is connected to the outer edge of vibration portion 11 on the positive side in the Z' direction and has an inclined portion whose thickness gradually increases in the positive Z' direction; connection portion 17c, which is connected to the outer edge of vibration portion 11 on the positive side in the X direction and has an inclined portion whose thickness gradually increases in the positive X direction; and connection portion 18c, which is connected to the outer edge of vibration portion 11 on the negative side in the X direction and has an inclined portion whose thickness gradually increases in the negative X direction.

[0051] The vibrating part 11 is connected to the support part 12c at its outer edge on the positive Z' side, the positive X side, and the negative X side, and the negative Z' side outer edge, which is part of the outer edge of the vibrating part 11, forms part of the outer edge of the quartz crystal substrate 10c. This further improves the rigidity of the vibrating part 11 of the vibrating element 1c.

[0052] In this embodiment, the vibration part 11 is formed by etching from one surface 14 side, but similar to the second and third embodiments, the vibration part 11 may also be formed by simultaneously etching from the other surface 15 side.

[0053] By adopting such a configuration, the vibration element 1c has a low CI value at high frequencies, and the vibration element 1c in which the rigidity of the vibration part 11 is further improved can be obtained.

[0054] 5. Fifth embodiment Next, a vibration element 1d according to a fifth embodiment will be described with reference to FIGS.

[0055] The vibration element 1d of this embodiment is similar to the vibration element 1 of the first embodiment except that the structure of the quartz crystal substrate 10d is different from that of the vibration element 1 of the first embodiment. The following description will focus on the differences from the first embodiment described above, and similar items will be denoted by the same reference numerals and their description will be omitted.

[0056] As shown in Figures 12 and 13, the vibration element 1d comprises a quartz crystal substrate 10d having a vibration portion 11 including a vibration region 13 and a support portion 12d that is thicker than the vibration portion 11, and excitation electrodes 31 and 32 arranged in the vibration region 13.

[0057] The support portion 12d protrudes from the vibrating portion 11 on the side of one surface 14 of the vibrating portion 11. In addition, the support portion 12d is provided with a connection portion 17d that is connected to the outer edge of the vibrating portion 11 on the positive side in the X direction, connecting the support portion 12d and the vibrating portion 11, and has an inclined portion whose thickness gradually increases toward the positive X direction.

[0058] The outer edge of the vibrating part 11 on the positive side in the X direction is connected to the support part 12d, and the outer edge on the positive side in the Z' direction, the outer edge on the negative side in the X direction, and the outer edge on the negative side in the Z' direction, which are part of the outer edge of the vibrating part 11, form part of the outer edge of the quartz crystal substrate 10d. This allows the vibrating region 13 of the vibrating part 11 to be wide.

[0059] In this embodiment, the vibration part 11 is formed by etching from one surface 14 side, but similar to the second and third embodiments, the vibration part 11 may also be formed by simultaneously etching from the other surface 15 side.

[0060] With this configuration, the vibration element 1d has a low CI value at high frequencies, and the vibration region 13 of the vibration part 11 is wide.

[0061] 6. Sixth embodiment Next, a vibration element 1e according to a sixth embodiment will be described with reference to FIGS.

[0062] The vibration element 1e of this embodiment is similar to the vibration element 1 of the first embodiment except that the structure of the quartz substrate 10e is different from that of the vibration element 1 of the first embodiment. The following description will focus on the differences from the first embodiment described above, and similar items will be assigned the same reference numerals and their description will be omitted.

[0063] As shown in Figures 14 and 15, the vibration element 1e comprises a quartz substrate 10e having a vibration portion 11 including a vibration region 13 and a support portion 12e that is thicker than the vibration portion 11, and excitation electrodes 31 and 32 arranged in the vibration region 13.

[0064] The support portion 12e protrudes from the vibrating portion 11 on the side of one surface 14 of the vibrating portion 11. Furthermore, the support portion 12e surrounds the vibrating portion 11 in a plan view. That is, the support portion 12e includes the following components that connect the support portion 12e and the vibrating portion 11: a connecting portion 16e that is connected to the outer edge of the vibrating portion 11 on the positive side in the Z' direction and has an inclined portion whose thickness gradually increases in the positive Z' direction; a connecting portion 17e that is connected to the outer edge of the vibrating portion 11 on the positive side in the X direction and has an inclined portion whose thickness gradually increases in the positive X direction; a connecting portion 18e that is connected to the outer edge of the vibrating portion 11 on the negative side in the X direction and has an inclined portion whose thickness gradually increases in the negative X direction; and a connecting portion 19e that is connected to the outer edge of the vibrating portion 11 on the negative side in the Z' direction and has an inclined portion whose thickness gradually increases in the negative Z' direction. This further improves the rigidity of the vibrating portion 11 of the vibration element 1e.

[0065] In this embodiment, the vibration part 11 is formed by etching from one surface 14 side, but similar to the second and third embodiments, the vibration part 11 may also be formed by simultaneously etching from the other surface 15 side.

[0066] With this configuration, the vibration element 1e has a low CI value at high frequencies, and the vibration part 11 has improved rigidity.

[0067] 7. Seventh embodiment Next, a vibrator 2 according to a seventh embodiment will be described with reference to Fig. 16 and Fig. 17. In this description, a vibrator 2 including the above-described vibrating element 1 will be described as an example. In Fig. 16, for convenience of explaining the internal configuration of the vibrator 2, the lid 21 is shown removed.

[0068] As shown in FIGS. 16 and 17, the vibrator 2 includes the vibrating element 1, a container 20 that houses the vibrating element 1, and a lid 21 that forms a housing space 23 together with the container 20.

[0069] The container 20 has a recess 22 that opens to the lid 21 side, and the lid 21 that closes the opening of the recess 22 is joined to an upper surface 27. By closing the recess 22 of the container 20 with the lid 21, an accommodation space 23 that accommodates the vibration element 1 is formed. The accommodation space 23 may be in a reduced pressure or vacuum state, or may be filled with an inert gas such as nitrogen (N), helium (He), or argon (Ar).

[0070] The material of the container 20 is not particularly limited, but various ceramics such as aluminum oxide can be used. The material of the lid 21 is not particularly limited, but it is preferable that the material has a linear expansion coefficient similar to that of the material of the container 20. The method of joining the container 20 and the lid 21 is not particularly limited, and they may be joined, for example, via an adhesive or by seam welding or the like.

[0071] Internal terminals 28 are formed on the inner bottom surface 24 of the container 20, and the internal terminals 28 are formed on a base portion 25 that protrudes from the inner bottom surface 24 toward the lid 21. In addition, a plurality of external terminals 29 are formed on the bottom surface 26 of the container 20. The internal terminals 28 on the inner bottom surface 24 are electrically connected to the external terminals 29 via through electrodes (not shown) formed in the container 20, and the internal terminals 28 on the base portion 25 are electrically connected to the external terminals 29 via through electrodes (not shown) formed in the container 20.

[0072] The vibration element 1 accommodated in the accommodation space 23 has one surface 14 of the vibrating part 11 facing the inner bottom surface 24 of the container 20, and is fixed to the container 20 at the support part 12 with a bonding member 50, which is a conductive adhesive. The bonding member 50 is provided in contact with the internal terminal 28 and the pad electrode 33. This electrically connects the internal terminal 28 and the pad electrode 33 via the bonding member 50. By supporting the vibration element 1 at one location or at one point using the bonding member 50, it is possible to suppress stress generated in the vibration element 1 due to, for example, the difference in thermal expansion coefficient between the container 20 and the quartz substrate 10.

[0073] The pad electrode 34 of the vibration element 1 is electrically connected to the internal terminal 28 via the bonding wire 60. As described above, the pad electrode 34 is disposed opposite the pad electrode 33, and is therefore located directly above the bonding member 50 when the vibration element 1 is fixed to the container 20. This makes it possible to suppress leakage of ultrasonic vibrations applied to the pad electrode 34 during wire bonding, and enables the bonding wire 60 to be connected to the pad electrode 34 more reliably.

[0074] With this configuration, the vibrator 2 includes the vibrating element 1 having a low CI value at high frequencies, so that the vibrator 2 can have a low CI value at high frequencies.

[0075] In the seventh embodiment, various ceramics have been mentioned as materials for forming the container 20 and the lid 21, but the present invention is not limited to these, and a semiconductor substrate may also be used.

[0076] 8. Eighth embodiment Next, an oscillator 3 according to an eighth embodiment will be described with reference to Figs. 18 and 19. In this description, an oscillator 3 including a vibrator 2 having the above-described vibrating element 1 will be described as an example. Also, in Fig. 18, for the convenience of explaining the internal configuration of the oscillator 3, a state in which the lid 41 is removed is illustrated. Also, in Fig. 19, the cross-sectional structure of the vibrator 2 is omitted from illustration, as it has been explained in Fig. 17 above.

[0077] As shown in Figures 18 and 19, the oscillator 3 includes a vibrator 2 having a vibration element 1, an oscillation circuit 70 that excites the vibration element 1, a container 40 that houses the vibrator 2 and the oscillation circuit 70, and a lid 41 that forms a housing space 43 with the container 40.

[0078] The container 40 has a recess 42 that opens to the lid 41 side, and the lid 41 that closes the opening of the recess 42 is joined to an upper surface 47. By closing the recess 42 of the container 40 with the lid 41, an accommodation space 43 that accommodates the vibrator 2 and the oscillation circuit 70 is formed.

[0079] The material of the container 40 is not particularly limited, but various ceramics such as aluminum oxide can be used. The material of the lid 41 is not particularly limited. The method of joining the container 40 and the lid 41 is not particularly limited, and they may be joined by, for example, an adhesive or by seam welding.

[0080] A plurality of internal terminals 48 are formed on the inner bottom surface 44 of the container 40. A plurality of external terminals 49 are formed on the bottom surface 46 of the container 40. Of the internal terminals 48 on the inner bottom surface 44, those arranged around the oscillation circuit 70 in a plan view are electrically connected to the external terminals 49 via wiring or through electrodes (not shown) formed in the container 40. Furthermore, those internal terminals 48 arranged at positions overlapping with the vibrator 2 in a plan view are electrically connected to the internal terminals 48 arranged around the oscillation circuit 70 via wiring (not shown).

[0081] The vibrator 2 housed in the housing space 43 is fixed to the container 40 at the external terminal 29 by a bonding member 51 such as a conductive adhesive or solder. The external terminal 29 and the internal terminal 48 are electrically connected via the bonding member 51.

[0082] The oscillator circuit 70 housed in the housing space 43 is fixed to the container 40 by a bonding member 52 such as an adhesive. A plurality of circuit terminals 71 are provided on the surface of the oscillator circuit 70 facing the lid 41, and the circuit terminals 71 are electrically connected to internal terminals 48 arranged around the oscillator circuit 70 via bonding wires 61. Some of the circuit terminals 71 are electrically connected to external terminals 29 of the vibrator 2 via the internal terminals 48, so that the vibrating element 1 can be excited. In addition, some of the circuit terminals 71 are electrically connected to external terminals 49 via the internal terminals 48, so that power can be input from the external terminals 49 and the oscillation frequency output from the oscillator circuit 70 can be output from the external terminals 49.

[0083] With this configuration, the oscillator 3 includes the vibration element 1 with a low CI value at high frequencies, so that the oscillator 3 has excellent oscillation characteristics at high frequencies.

[0084] In the eighth embodiment, the vibrator 2, in which the vibrating element 1 is housed in the container 20, is fixed to the container 40, but the vibrating element 1 itself may be attached to the container 40. Although not shown, a semiconductor substrate on which an oscillation circuit 70 is formed may also be used as the container 40. By mounting the vibrating element 1 on the semiconductor substrate, space for the oscillation circuit 70 in the housing space 43 is not required, and the oscillator 3 can be made smaller. [Explanation of symbols]

[0085] 1, 1a, 1b, 1c, 1d, 1e... vibration element, 2... vibrator, 3... oscillator, 10... quartz crystal substrate, 11... vibration part, 12... support part, 13... vibration area, 14... one surface, 15... other surface, 16... connection part, 17... connection part, 20... container, 21... lid, 22... recess, 23... accommodation space, 24... inner bottom surface, 25... base part, 26... lower surface, 27... upper surface, 28... internal terminal, 2 9...external terminal, 31, 32...excitation electrode, 33, 34...pad electrode, 35, 36...extraction electrode, 40...container, 41...lid, 42...recess, 43...accommodation space, 44...inner bottom surface, 46...lower surface, 47...upper surface, 48...internal terminal, 49...external terminal, 50, 51, 52...bonding member, 60, 61...bonding wire, 70...oscillator circuit, 71...circuit terminal, Y...approximate curve.

Claims

1. a quartz crystal substrate having a vibration part including a vibration region and a support part having a thickness greater than that of the vibration part; an excitation electrode disposed in the vibration region; The thickness variation in the vibration region of the quartz crystal substrate is defined as y [nm], When the oscillation frequency is x [MHz], y≦329.8exp(-x / 76.7)+4.0 Satisfy the relationship of Vibration element.

2. The thickness variation is 12 nm or less, and the oscillation frequency is 285 MHz or less. The vibration element according to claim 1 .

3. The thickness variation is 5 nm or less, and the oscillation frequency is 492 MHz or less. The vibration element according to claim 1 .

4. The thickness variation is 4 nm or less, and the oscillation frequency is 700 MHz or less. The vibration element according to claim 1 .

5. The support portion protrudes from the vibration portion on one surface side of the vibration portion. The vibration element according to claim 1 .

6. The support portion also protrudes further than the vibration portion on the other surface side, which is the back side of the one surface. The vibration element according to claim 5 .

7. The support portion is a first support portion disposed along one outer edge of the vibration portion; a second support portion disposed along the other outer edge opposite to the one outer edge with respect to the vibration portion, the first support portion protrudes from the vibration portion on one surface side of the vibration portion, The second support portion protrudes from the vibration portion on the other surface side behind the one surface. The vibration element according to claim 1 .

8. A part of the outer edge of the vibrating part constitutes a part of the outer edge of the quartz crystal substrate. The vibration element according to claim 1 .

9. The support portion surrounds the vibration portion in a plan view. The vibration element according to claim 1 .

10. The vibration element according to any one of claims 1 to 4, a container that accommodates the vibration element; Equipped with Vibrator.

11. The vibration element according to any one of claims 1 to 4, an oscillation circuit that excites the vibration element; a container that accommodates the vibration element and the oscillation circuit; Equipped with Oscillator.

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