Vibration device
By optimizing the shape spacing between the vibration part and the excitation electrode and using the metal bump to the base, and forming a storage space with the cover, the problems of deterioration of vibration characteristics and lowering of Q value in the prior art are solved, and high Q value is achieved Vibration device.
Patent Information
- Application Number
- CN202410759335.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-06-16
- Filing Date
- 2024-06-13
- Publication Date
- 2024-12-17
AI Technical Summary
When using metal bumps as joints, the existing vibrating devices have higher hardness, resulting in deterioration of vibration characteristics and lowering of Q value.
By optimizing the shape distance between the vibration part and the excitation electrode, ensuring that the distances D1/L1 and D2/L1 are between 0.03 and 0.07, the metal bumps and the base are engaged to reduce the influence of the metal bumps on the vibration characteristics, and through The cover forms a storage space to reduce viscosity resistance and improve oscillation characteristics.
The Q value of the vibrating device is significantly improved, the closing efficiency of the vibration energy is increased, and even when the metal bumps with high hardness are bonded, a high Q value vibrating element can be obtained.
Smart Images
Figure CN119154824A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a vibrating device. Background Art
[0002] The following vibration device is well known: the vibration device has a vibration element with a table-type structure, the vibration element with a table-type structure has a vibrating part that vibrates and a thin-walled part that is thinner than the vibration part and integrated with the outer edge of the vibration part. The vibration device confines the vibration energy in the vibration part to improve the Q value.
[0003] For example, Patent Document 1 discloses a vibrator as a vibration device in which the amplitude of bending vibration generated in a vibrating piece having a mesa structure as a vibration element is attenuated by optimizing the size of a bonding material for bonding a base substrate.
[0004] Patent Document 1: Japanese Patent Application Publication No. 2016-152477
[0005] However, when the vibration device described in Patent Document 1 uses metal bumps as bonding materials, the metal bumps have a higher hardness than the conductive adhesive, and thus have a greater influence on the vibration state of the vibration element, resulting in deterioration of vibration characteristics and reduction of Q value. Summary of the invention
[0006] The vibration device includes: a base; and a vibration element, which has a vibration part and a thin-walled part thinner than the vibration part, when viewed from above, an excitation electrode is formed at a position closer to the inside than the outer shape of the vibration part, the vibration element includes a first side and a second side opposite to the first side, when viewed from above, the first side and the vibration part are connected to the base by means of a metal bump, the vibration part includes a third side located on the first side and a fourth side located on the second side, the excitation electrode includes a fifth side along the third side and a sixth side along the fourth side, and when the distance between the third side and the fourth side is L1, the distance between the third side and the fifth side is D1, and the distance between the fourth side and the sixth side is D2, at least one of 0.03≤D1 / L1≤0.07 and 0.03≤D2 / L1≤0.07 is satisfied. BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Figure 1 It is a plan view showing a schematic structure of the vibration device according to the first embodiment.
[0008] Figure 2 yes Figure 1 Cross-sectional view at line A1-A1.
[0009] Figure 3It is a plan view showing a schematic structure of a vibration element included in the vibration device according to the first embodiment.
[0010] Figure 4 yes Figure 3 Cross-sectional view at line A2-A2.
[0011] Figure 5 This is a diagram showing the Q value of the vibration element with respect to the distance between the outer shape of the vibration part and the outer shape of the excitation electrode.
[0012] Figure 6 It is a plan view showing a schematic structure of a vibration device according to a second embodiment.
[0013] Figure 7 yes Figure 6 Cross-sectional view at line B1-B1.
[0014] Figure 8 It is a plan view showing a schematic structure of a vibration element included in the vibration device according to the second embodiment.
[0015] Fig. 9 yes Figure 8 Cross-sectional view at line B2-B2.
[0016] Fig.10 It is a plan view showing a schematic structure of a vibration device according to a third embodiment.
[0017] Fig.11 yes Fig.10 Cross-sectional view at line C1-C1.
[0018] Fig.12 It is a plan view showing a schematic structure of a vibration element included in the vibration device according to the third embodiment.
[0019] Fig.13 yes Fig.12 Cross-sectional view at line C2-C2.
[0020] Fig.14 It is a plan view showing a schematic structure of a vibration device according to a fourth embodiment.
[0021] Fig.15 yes Fig.14 Cross-sectional view at line DD.
[0022] Description of symbols
[0023] 1, 1a, 1b, 1c: vibration device; 10: base; 11: first surface; 12: second surface; 13: oscillation circuit; 14: internal terminal; 15: external terminal; 16: cover; 17: bonding component; 18: quartz substrate; 19: bonding component; 20: vibration element; 21: substrate; 22: vibration part; 23: thin-walled part; 24: supporting part; 25: recessed part; 26: storage space; 27: metal bump; 31: excitation electrode; 32: pad electrode; 33: lead electrode; 34: side electrode; 41: first side; 42: second side; 43: third side; 44: fourth side; 45: fifth side; 46: sixth side; D1, D2, L1: distance. DETAILED DESCRIPTION
[0024] 1. First Implementation
[0025] First, refer to Figure 1 to Figure 5 The vibration device 1 according to the first embodiment will be described.
[0026] In addition, for the sake of convenience, in the following figures, the X-axis, Y-axis, and Z-axis are illustrated as three axes perpendicular to each other. In addition, the direction along the X-axis is referred to as the "X direction", the direction along the Y-axis is referred to as the "Y direction", and the direction along the Z-axis is referred to as the "Z direction". In addition, the front end side of the arrow in each axis direction is also referred to as the "positive side", the base end side is referred to as the "negative side", the positive side in the Z direction is referred to as "upper", and the negative side in the Z direction is referred to as "lower".
[0027] like Figure 1 and Figure 2 As shown, the vibration device 1 has: a base 10; a vibration element 20, which is arranged on the first surface 11 of the base 10; a metal bump 27, which connects the vibration element 20 to the base 10; and a cover 16, which covers the vibration element 20 and is connected to the first surface 11 of the base 10.
[0028] The base 10 is a silicon substrate having a first surface 11 and a second surface 12 in a positive and negative relationship. The vibration element 20 is bonded to the first surface 11 by means of a metal bump 27, and the base 10 is provided with two internal terminals 14. In addition, an oscillation circuit 13 electrically connected to the vibration element 20 is provided on the silicon substrate. In addition, in the present embodiment, the oscillation circuit 13 is provided on the side of the first surface 11 of the silicon substrate, i.e., the base 10. In other words, the base 10 is a semiconductor integrated circuit substrate having the first surface 11 as an active surface. The oscillation circuit 13 causes the vibration element 20 to oscillate and generates the frequency of a reference signal such as a clock signal. In addition, the oscillation circuit 13 is electrically connected to the internal terminal 14.
[0029] A plurality of external terminals 15 for outputting the frequency of the reference signal are provided on the second surface 12 of the base 10. The external terminals 15 are electrically connected to the oscillation circuit 13 via wiring or through-electrodes (not shown). In addition, the external terminals 15 may be arranged with the base 10 interposed with an insulating layer (not shown).
[0030] The cover 16 is provided with a recess 25 opened toward the side of the base 10, and is joined to the first surface 11 of the base 10 via the joining member 17, and together with the base 10, forms a storage space 26 for storing the vibration element 20. In addition, the storage space 26 is in a reduced pressure state, preferably a state closer to a vacuum. As a result, the viscous resistance is reduced, and the oscillation characteristics of the vibration element 20 are improved. In addition, as a constituent material of the cover 16, silicon is preferred, and glass, ceramics, etc. may also be used.
[0031] like Figure 3 and Figure 4 As shown, the vibration element 20 includes: a substrate 21 having a vibration portion 22, a thin-walled portion 23, and a support portion 24; an excitation electrode 31 provided on the upper and lower surfaces of the vibration portion 22; and two pad electrodes 32 provided on the lower surface of the support portion 24. In addition, the vibration element 20 includes a first side 41 on the negative side in the X direction and a second side 42 on the opposite side to the first side 41, that is, on the positive side in the X direction, and is bonded to the base 10 at the support portion 24 between the first side 41 and the vibration portion 22 by means of a metal bump 27.
[0032] The substrate 21 is a rectangular shape having a long length in the X direction, and has a vibration portion 22, a thin-walled portion 23 having a thickness thinner than the vibration portion 22, and a support portion 24 having a thickness thicker than the thin-walled portion 23. The support portion 24 is connected to the vibration portion 22 via the thin-walled portion 23, and is bonded to the base 10 by means of a metal bump 27. In addition, the thin-walled portion 23 is configured to surround the vibration portion 22 when viewed from above, and is recessed from the upper surface and the lower surface of the vibration portion 22 to the same depth. Therefore, the substrate 21 has a double-sided mesa structure. In addition, the constituent material of the substrate 21 is quartz, preferably an AT-cut quartz substrate.
[0033] The excitation electrodes 31 provided on the upper and lower surfaces of the vibration part 22 are formed at positions further inside than the outer shape of the vibration part 22 in a plan view, and the two excitation electrodes 31 are arranged in an overlapping manner. The excitation electrode 31 provided on the upper surface of the vibration part 22 is electrically connected to one pad electrode 32 via a lead electrode 33 extending to the negative side in the X direction and a side electrode 34 provided on the side surface on the negative side in the X direction of the substrate 21. In addition, the excitation electrode 31 provided on the lower surface of the vibration part 22 is electrically connected to the other pad electrode 32 via a lead electrode 33 extending to the negative side in the X direction.
[0034] The two pad electrodes 32 of the vibration element 20 are arranged at positions overlapping the two internal terminals 14 provided on the first surface 11 of the base 10, and are mechanically and electrically bonded together via the metal bumps 27. Therefore, the excitation electrodes 31 provided on the upper and lower surfaces of the vibration part 22 are electrically connected to the oscillation circuit 13 provided on the base 10, so that the vibration element 20 can be oscillated.
[0035] The vibration element 20 is formed into a cantilever beam structure in which the support portion 24 arranged on the first side 41 is joined to the base 10 by the metal bump 27, and the interval from the metal bump 27 to the vibration portion 22 can be extended, and the influence of the residual stress of the metal bump 27 accompanying the joining on the vibration characteristics can be reduced. Therefore, the longer the interval from the metal bump 27 to the vibration portion 22, the less the influence on the vibration characteristics can be. However, the length of the vibration element 20 in the X direction becomes longer, and miniaturization becomes a problem.
[0036] Therefore, as a method of improving the Q value of the vibration element 20 while miniaturizing the vibration element 20 , the influence of the distance between the outer shape of the vibration portion 22 serving as the mesa portion and the outer shape of the excitation electrode 31 on the Q value of the vibration element 20 was investigated.
[0037] like Figure 3 As shown in FIG. 1 , assuming that the distance between the third side 43 of the vibration portion 22 located on the first side 41 side and the fourth side 44 located on the second side 42 side is L1, the distance between the fifth side 45 of the excitation electrode 31 along the third side 43 and the third side 43 of the vibration portion 22 is D1, and the distance between the sixth side 46 of the excitation electrode 31 along the fourth side 44 and the fourth side 44 of the vibration portion 22 is D2, in Figure 5 2 shows the result of simulation of the Q value of the vibration element 20 when the distance D1 or the distance D2 is changed.
[0038] In addition, the vibration element 20 used in the simulation Figure 3 as well as Figure 4 The dimensions of the parts shown are set to L=720μm, L1=453μm, L2=89μm, L3=90μm, M=493μm, M1=31.5μm, t1=28.5μm, h1=2μm, and the simulation is performed by changing D1 and D2 to 0μm to 43.5μm.
[0039] exist Figure 5In the figure, the horizontal axis represents D1 / L1 or D2 / L1 based on the distance L1, and the vertical axis represents Q / Q0 based on the Q value of the vibration element 20 when the distance D1 and the distance D2 are zero, and the results of the simulation of the Q value relative to D1 / L1 or D2 / L1 are plotted to show an approximate curve. In addition, in this simulation, the case where the distance D1 and the distance D2 are the same value and the case where the step difference of the upper surface, that is, the length h1 and the step difference of the lower surface are the same value are simulated.
[0040] Figure 5 The approximate curve shown shows that Q / Q0 increases from around 0.025 as D1 / L1 or D2 / L1 increases, and Q / Q0 reaches a maximum value around 0.048. After that, Q / Q0 shows a tendency to decrease as D1 / L1 or D2 / L1 increases.
[0041] according to Figure 5 When the relationship between the distance L1 and the distance D1 and the distance D2 satisfies 0.03≤D1 / L1≤0.07 and 0.03≤D2 / L1≤0.07, the Q value can be increased by more than 1.2 times compared with the Q0 value of the vibration element 20 when the distance D1 and the distance D2 are zero.
[0042] In addition, according to Figure 5 When the relationship between the distance L1 and the distance D1 and the distance D2 satisfies 0.036≤D1 / L1≤0.062 and 0.036≤D2 / L1≤0.062, the Q value can be increased by more than three times compared with the Q0 value of the vibration element 20 when the distance D1 and the distance D2 are zero.
[0043] In addition, according to Figure 5 When the relationship between the distance L1 and the distance D1 and the distance D2 satisfies 0.04≤D1 / L1≤0.058 and 0.04≤D2 / L1≤0.058, the Q value can be increased by more than 5 times compared with the Q0 value of the vibration element 20 when the distance D1 and the distance D2 are zero.
[0044] Therefore, by setting the distances D1 and D2 between the outer shape of the vibration part 22 and the outer shape of the excitation electrode 31 to the above range, the vibration energy can be efficiently confined in the region of the excitation electrode 31, and therefore, even when bonding is performed using the metal bump 27 having a higher hardness than the conductive adhesive, the Q value of the vibration element 20 can be increased compared to the Q0 value of the vibration element 20 when the distance D1 and the distance D2 are zero. In addition, even when either the distance D1 or the distance D2 is set to the above range, the Q value of the vibration element 20 can be increased compared to the Q0 value of the vibration element 20 when the distance D1 and the distance D2 are zero.
[0045] As described above, in the vibration device 1 of the present embodiment, the relationship between the distance L1 between the third side 43 and the fourth side 44, the distance D1 between the third side 43 and the fifth side 45, and the distance D2 between the fourth side 44 and the sixth side 46 satisfies at least one of 0.03≤D1 / L1≤0.07 and 0.03≤D2 / L1≤0.07, and therefore, the Q value can be increased compared to the Q0 value of the vibration element 20 when the distance D1 and the distance D2 are zero. Therefore, compared to the degradation of the Q value caused by bonding the vibration element 20 of the mesa structure to the base 10 using the metal bump 27 having a higher hardness than the conductive adhesive, the Q value can be improved based on the vibration energy confinement effect, and the vibration device 1 having the vibration element 20 with a high Q value can be obtained.
[0046] Furthermore, since the relationship between the distance L1 and the distance D1 and the distance D2 satisfies at least one of 0.036≤D1 / L1≤0.062 and 0.036≤D2 / L1≤0.062, the Q value can be further increased compared to the Q0 value when the distance D1 and the distance D2 are zero.
[0047] Furthermore, since the relationship between the distance L1 and the distances D1 and D2 satisfies at least one of 0.04≤D1 / L1≤0.058 and 0.04≤D2 / L1≤0.058, the Q value can be increased more significantly than the Q0 value when the distances D1 and D2 are zero.
[0048] 2. Second Implementation
[0049] Next, refer to Figure 6 to Figure 9 A resonator device 1 a according to the second embodiment will be described.
[0050] The resonator device 1a of this embodiment is the same as the resonator device 1 of the first embodiment except that the structure of the resonator element 20a is different from that of the first embodiment. The description will focus on the differences from the first embodiment, and the description of the same matters will be omitted.
[0051] like Figure 6 and Figure 7 As shown, the vibration device 1a has: a base 10; a vibration element 20a, which is arranged on the first surface 11 of the base 10; a metal bump 27, which connects the vibration element 20a to the base 10; and a cover 16, which covers the vibration element 20a and is connected to the first surface 11 of the base 10.
[0052] like Figure 8 and Fig. 9 As shown, the substrate 21a of the vibration element 20a is a rectangular shape having a long length in the X direction, and has a vibration portion 22, a thin portion 23 thinner than the vibration portion 22, and a support portion 24a having the same thickness as the thin portion 23. The support portion 24a is connected to the vibration portion 22 via the thin portion 23.
[0053] Although the support portion 24a and the thin-walled portion 23 of the vibration element 20a of the vibration device 1a of this embodiment have the same thickness, the same effect as the first embodiment can be obtained by setting the distances D1 and D2 between the outer shape of the vibration portion 22 and the outer shape of the excitation electrode 31 to a specified range.
[0054] 3. Third Implementation
[0055] Next, refer to Figure 10 to Figure 13 A resonator device 1 b according to the third embodiment will be described.
[0056] The resonator device 1b of this embodiment is the same as the resonator device 1 of the first embodiment except that the structure of the resonator element 20b is different from that of the resonator device 1 of the first embodiment. The description will focus on the differences from the first embodiment, and the description of the same matters will be omitted.
[0057] like Fig.10 and Fig.11 As shown, the vibration device 1b has: a base 10; a vibration element 20b, which is arranged on the first surface 11 of the base 10; a metal bump 27, which connects the vibration element 20b to the base 10; and a cover 16, which covers the vibration element 20b and is connected to the first surface 11 of the base 10.
[0058] like Fig.12 and Fig.13 As shown, the substrate 21b of the vibration element 20b is a rectangular shape having a long length in the X direction, and has a vibration part 22b, a thin-walled part 23b thinner than the vibration part 22b, and a support part 24b thicker than the thin-walled part 23b. The support part 24b is connected to the vibration part 22b via the thin-walled part 23b.
[0059] The thin wall portion 23b of the vibration element 20b is arranged to surround the vibration portion 22b in a plan view and to be recessed from the lower surface of the vibration portion 22b. Therefore, the substrate 21b has a single-sided mesa structure having a flat upper surface and a mesa portion on the lower surface.
[0060] Although the vibration element 20b of the vibration device 1b of this embodiment has a single-sided mesa structure, the same effect as that of the first embodiment can be obtained by setting the distances D1 and D2 between the outer shape of the vibration part 22b and the outer shape of the excitation electrode 31 to a predetermined range.
[0061] 4. Fourth Implementation
[0062] Next, refer to Fig.14 and Fig.15 A resonator device 1 c according to a fourth embodiment will be described.
[0063] The resonator device 1c of this embodiment is the same as the resonator device 1 of the first embodiment except that a quartz substrate 18 is arranged between the metal bump 27 and the base 10. The description will focus on the differences from the first embodiment, and the description of the same matters will be omitted.
[0064] like Fig.14 and Fig.15 As shown, the vibration device 1c includes: a base 10; a vibration element 20 disposed on the first surface 11 of the base 10; a metal bump 27 that joins the vibration element 20 to the base 10; a quartz substrate 18 disposed between the metal bump 27 and the base 10; and a cover 16 that covers the vibration element 20 and joins to the first surface 11 of the base 10. In addition, the vibration element 20 is a quartz vibration element.
[0065] The vibration device 1c has a quartz substrate 18 disposed between the metal bump 27 and the base 10. The quartz substrate 18 is bonded to the base 10 via a bonding member 19. Therefore, compared with a case where the vibration element 20 is directly bonded to the base 10 via the metal bump 27, stress generated by the difference in linear expansion coefficient between the base 10 and the vibration element 20 can be reduced. In addition, it is preferable that the crystal direction of the quartz substrate 18 is the same as that of the vibration element 20. By making the crystal directions the same, stress generated by the difference in linear expansion coefficient between the base 10 and the vibration element 20 can be further reduced.
[0066] The vibration device 1c of this embodiment has a quartz substrate 18 arranged between the metal bump 27 and the base 10, so that the stress generated by the difference in linear expansion coefficient between the base 10 and the vibration element 20 can be reduced. By making the distance between the outer shape of the vibration part 22 and the outer shape of the excitation electrode 31, that is, the distance D1 and the distance D2, within the specified range, the same effect as the first embodiment can be obtained.
[0067] 5. Modifications
[0068] In addition, the present invention is not limited to the above-mentioned embodiment, and various modifications can be implemented within the scope of the gist of the present invention.
[0069] In the first to fourth embodiments described above, the oscillation circuit 13 is formed on the first surface 11 side of the base 10, but the oscillation circuit 13 may be formed on the second surface 12 side of the base 10. In this case, a through electrode may be formed on the base 10, the through electrode penetrating from the first surface 11 to the second surface 12 of the base 10 to electrically connect the vibration element 20 and the oscillation circuit 13.
Claims
1. A vibration device, comprising: a base; and A vibration element having a vibration portion and a thin-walled portion thinner than the vibration portion, wherein an excitation electrode is formed at a position inside the outer shape of the vibration portion in a plan view, The vibration element includes a first side and a second side opposite to the first side, and is bonded to the base via a metal bump between the first side and the vibration part when viewed from above. The vibration portion includes a third side located on the first side and a fourth side located on the second side, The excitation electrode includes a fifth side along the third side and a sixth side along the fourth side, When the distance between the third side and the fourth side is L1, the distance between the third side and the fifth side is D1, and the distance between the fourth side and the sixth side is D2, At least one of 0.03≤D1 / L1≤0.07 and 0.03≤D2 / L1≤0.07 is satisfied.
2. The vibration device according to claim 1, wherein The L1, the D1, and the D2 satisfy at least one of 0.036≤D1 / L1≤0.062 and 0.036≤D2 / L1≤0.
062.
3. The vibration device according to claim 1, wherein The L1, the D1, and the D2 satisfy at least one of 0.04≤D1 / L1≤0.058 and 0.04≤D2 / L1≤0.
058.
4. The vibration device according to claim 1, wherein The vibration device includes a support portion, the support portion is connected to the vibration portion via the thin-walled portion and is thicker than the thin-walled portion. The support portion is engaged with the base by means of the metal bump.
5. The vibration device according to any one of claims 1 to 4, wherein: The base includes a silicon substrate.
6. The vibration device according to claim 5, wherein: The vibration device further includes a cover body, the cover body is bonded to the silicon substrate, and the vibration element is accommodated between the cover body and the silicon substrate. The silicon substrate includes a first surface and a second surface opposite to the first surface. The vibration element is bonded to the first surface side via the metal bump, and an oscillation circuit electrically connected to the vibration element is formed on the silicon substrate.
7. The vibration device according to claim 1, wherein The vibration element is a quartz vibration element, A quartz substrate is provided between the metal bump and the base.