Vibrating element

Abstract

To provide a vibrating element in which a damage due to an impact or the like can be suppressed.SOLUTION: A vibrating element includes: a vibrating substrate having a plate shape with a first surface and a second surface in a front and back relation and including a vibrating part, a supporting part, and a coupling part that couples the vibrating part and the supporting part and has a part being thinner than the supporting part; an electrode layer including a first excitation electrode disposed on the first surface of the vibrating part, a second excitation electrode disposed on the second surface of the vibrating part, a first pad electrode disposed on the supporting part, a second pad electrode disposed on the supporting part, a first connection electrode disposed on the coupling part and connecting the first excitation electrode and the first pad electrode, and a second connection electrode disposed on the coupling part and connecting the second excitation electrode and the second pad electrode; a first metal film disposed in an upper layer of the first connection electrode existing in the coupling part and being thicker than the electrode layer; and a second metal film disposed in an upper layer of the second connection electrode existing in the coupling part and being thicker than the electrode layer.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a vibration element. [Background technology]

[0002] The vibration element described in Patent Document 1 has a vibration substrate and an electrode arranged on the vibration substrate. The vibration substrate has a vibration section, a support section that supports the vibration section, and a connecting section that connects the vibration section and the support section, and the connecting section is thinner than the support section and the vibration section. Such a vibration element is fixed to a fixing object such as a package at the support section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-141317 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the vibration element of Patent Document 1, the connecting portion is thinner than the support portion and the vibration portion, and therefore there is a problem in that the connecting portion is easily damaged by an external impact or the like. [Means for solving the problem]

[0005] The vibration element of the present invention includes a vibration substrate having a plate shape with a first surface and a second surface that are reversed, the vibration substrate having a vibration section, a support section, and a connecting section that connects the vibration section and the support section and has a portion that is thinner than the support section; an electrode layer including a first excitation electrode arranged on the first surface of the vibration section, a second excitation electrode arranged on the second surface of the vibration section, a first pad electrode arranged on the support section, a second pad electrode arranged on the support section, a first connection electrode arranged on the connecting section and connecting the first excitation electrode and the first pad electrode, and a second connection electrode arranged on the connecting section and connecting the second excitation electrode and the second pad electrode; a first metal film disposed on an upper layer of the first connection electrode located at the coupling portion and having a thickness greater than that of the electrode layer; The second metal film is disposed in an upper layer of the second connection electrode located in the coupling portion and has a thickness greater than that of the electrode layer. [Brief description of the drawings]

[0006] [Figure 1] 1 is a cross-sectional view showing a vibrator according to a first embodiment of the present invention. [Diagram 2] 2 is a top view showing a vibration element of the vibrator of FIG. 1. [Diagram 3] FIG. [Figure 4] 3 is a cross-sectional view taken along line AA in FIG. 2. [Diagram 5] FIG. 3 is a cross-sectional view taken along line BB in FIG. [Figure 6] FIG. 4 is a top view of the vibration element with the metal film omitted. [Figure 7] FIG. 13 is a top view showing a modified example of the vibration element. [Figure 8] FIG. 13 is a top view showing a modified example of the vibration element. [Figure 9] FIG. 13 is a top view showing a modified example of the vibration element. [Figure 10] FIG. 13 is a top view showing a modified example of the vibration element. [Figure 11] 5A to 5C are cross-sectional views illustrating a method for manufacturing the vibration element. [Figure 12] 5A to 5C are cross-sectional views illustrating a method for manufacturing the vibration element. [Figure 13] 5A to 5C are cross-sectional views illustrating a method for manufacturing the vibration element. [Figure 14] 5A to 5C are cross-sectional views illustrating a method for manufacturing the vibration element. [Figure 15] 5A to 5C are cross-sectional views illustrating a method for manufacturing the vibration element. [Figure 16] 5A to 5C are cross-sectional views illustrating a method for manufacturing the vibration element. [Figure 17] FIG. 4 is a cross-sectional view showing a vibration element according to a second embodiment of the present invention. [Figure 18] FIG. 4 is a cross-sectional view showing a vibration element according to a second embodiment of the present invention. [Figure 19] FIG. 4 is a cross-sectional view showing a vibration element according to a third embodiment of the present invention. [Figure 20] FIG. 4 is a cross-sectional view showing a vibration element according to a third embodiment of the present invention. [Figure 21] FIG. 11 is a plan view showing a vibration element according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a vibration element of the present invention will be described in detail based on embodiments shown in the accompanying drawings.

[0008] First Embodiment FIG. 1 is a cross-sectional view showing a vibrator according to a first embodiment of the present invention. FIG. 2 is a top view showing a vibration element included in the vibrator of FIG. 1. FIG. 3 is a perspective view of the vibration element. FIG. 4 is a cross-sectional view taken along line AA in FIG. 2. FIG. 5 is a cross-sectional view taken along line BB in FIG. 2. FIG. 6 is a top view of the vibration element with the metal film omitted. FIGS. 7 to 10 are top views showing modified examples of the vibration element. FIGS. 11 to 16 are cross-sectional views for explaining a manufacturing method of the vibration element.

[0009] The vibrator 1 shown in FIG. 1 has a package 2 and a vibrating element 3 housed in the package 2.

[0010] The package 2 also has a base 21 and a lid 22. The base 21 is box-shaped and has a recess 211 that opens on its upper surface. The vibration element 3 is mounted on the bottom surface of the recess 211 by bonding members B1 and B2. On the other hand, the lid 22 is plate-shaped and is bonded to the upper surface of the base 21 via a sealing member 23 such as a seal ring or low-melting glass so as to close the opening of the recess 211. This makes the recess 211 airtightly sealed, and a storage space S is formed in the package 2. The storage space S is airtight and in a reduced pressure state, preferably a vacuum or a state close to it. This reduces viscous resistance and improves the oscillation characteristics of the vibration element 3.

[0011] There are no particular limitations on the materials that make up the base 21 and the lid 22. For example, the base 21 can be made of various ceramic materials such as alumina and titania, and the lid 22 can be made of various metal materials such as kovar. This reduces the difference in linear expansion coefficient between the base 21 and the lid 22, resulting in a package 2 that is less susceptible to thermal stress.

[0012] Further, a pair of internal terminals 241, 242 are arranged on the bottom surface of the recess 211, and a pair of external terminals 251, 252 are arranged on the lower surface of the base 21. The internal terminal 241 is electrically connected to the external terminal 251 via an internal wiring (not shown) formed in the base 21. Similarly, the internal terminal 242 is electrically connected to the external terminal 252 via the internal wiring. Further, the internal terminal 241 is electrically connected to the vibration element 3 via a conductive bonding member B1, and the internal terminal 242 is electrically connected to the vibration element 3 via a conductive bonding member B2.

[0013] The bonding members B1 and B2 are not particularly limited as long as they have both electrical conductivity and bonding properties. For example, various metal bumps such as gold bumps, silver bumps, copper bumps, solder bumps, etc., various conductive pastes such as silver paste and copper paste, conductive adhesives in which conductive fillers such as silver fillers are dispersed in various adhesives such as polyimide, epoxy, silicone, and acrylic adhesives, etc. can be used. When the former metal bumps are used as the bonding members B1 and B2, gas generation from the bonding members B1 and B2 can be suppressed, and environmental changes in the storage space S, particularly pressure increases, can be effectively suppressed. In addition, since the bonding members B1 and B2 do not wet and spread, the bonding members B1 and B2 can be arranged at a narrow pitch, and the vibrator 1 can be made smaller. On the other hand, when the latter conductive adhesive is used as the bonding members B1 and B2, the bonding members B1 and B2 become softer than the metal bumps, and stress is less likely to be transmitted to the vibration element 3.

[0014] As shown in Fig. 2 and Fig. 3, the vibration element 3 has a vibration substrate 4 which is an AT-cut quartz substrate, and an electrode layer 5 and a metal film 6 arranged on the vibration substrate 4. The AT-cut quartz substrate has a thickness-shear vibration mode and has a third-order frequency-temperature characteristic. Therefore, the vibration element 3 has excellent temperature characteristics. However, the cut angle of the vibration substrate 4 is not particularly limited.

[0015] To briefly explain the AT-cut quartz substrate, the quartz substrate has crystal axes X, Y, and Z that are perpendicular to each other. The X-axis, Y-axis, and Z-axis are called the electrical axis, mechanical axis, and optical axis, respectively. The AT-cut quartz substrate is a "rotated Y-cut quartz substrate" cut along a plane obtained by rotating the XZ plane around the X-axis by a certain angle θ, and a substrate cut along a plane rotated θ=35°15' is called an "AT-cut quartz substrate". In the following, the Y-axis and Z-axis rotated around the X-axis corresponding to the angle θ are called the Y'-axis and Z'-axis. In other words, the quartz substrate has a thickness in the Y'-axis direction and a spread in the X-Z'-plane direction. In the following, the arrow tip side of each axis is also called the "plus side", and the opposite side is also called the "minus side".

[0016] The vibrating substrate 4 is plate-shaped and has an upper surface 4a as the first surface and a lower surface 4b as the second surface, which are in a front-back relationship. Also, in plan view, the vibrating substrate 4 is rectangular, particularly a rectangle with its longitudinal direction along the X-axis direction. However, the shape of the vibrating substrate 4 in plan view is not particularly limited, and for example, it may be square, or may have a shape other than a rectangle such as circular or elliptical. Further, the vibrating substrate 4 has a vibrating portion 41, a supporting portion 42 that supports the vibrating portion 41, and a connecting portion 43 that is located between the vibrating portion 41 and the supporting portion 42 and connects them. Also, the supporting portion 42 is located on the minus side in the X-axis direction of the vibrating portion 41. Such a vibrating element 3 is fixed to the base 21 via joining members B1 and B2 at the supporting portion 42 as shown in FIG. 2.

[0017] In this embodiment, the vibrating portion 41 has a configuration with a uniform thickness throughout, but it is not limited to this, and it may be a so-called "mesa type" or "inverted mesa type".

[0018] Also, the supporting portion 42 and the vibrating portion 41 have the same thickness as each other. In contrast, the connecting portion 43 has a smaller thickness than the supporting portion 42. That is, as shown in FIGS. 4 and 5, when the thickness of the vibrating portion 41 is t1, the thickness of the supporting portion 42 is t2, and the thickness of the connecting portion 43 is t3, then t3 < t1 and t3 < t2. Thereby, the connecting portion 43 becomes the thinnest portion within the vibrating substrate 4. Therefore, the connecting portion 43 is easily deformed, and the stress applied from the base 21, particularly the thermal stress caused by the difference in the linear expansion coefficients between the base 21 and the vibrating substrate 4, can be effectively absorbed and relaxed. Therefore, it becomes difficult for stress to be transmitted to the vibrating portion 41, and fluctuations in the vibration characteristics can be effectively suppressed. Thus, a vibrating element 3 having excellent vibration characteristics is obtained.

[0019] t1 and t2 are not particularly limited and may vary depending on the frequency of the vibration element 3, but may be, for example, about 30 μm or more and 100 μm or less. t3 is not particularly limited and may vary depending on the dimensions of the vibration part 41, but may be, for example, about 5 μm or more and 15 μm or less, and more preferably about 10 μm. This makes the connecting part 43 sufficiently soft, and the stress from the base 21 can be absorbed and relaxed more effectively. In this embodiment, the entire connecting part 43 is thinner than the support part 42 and the vibration part 41, but is not limited thereto, and it is sufficient that at least a part of the connecting part 43 is thinner than the support part 42 and the vibration part 41.

[0020] The connecting portion 43 is formed with a recess on both the top and bottom sides. That is, the top surface 4a of the connecting portion 43 is located below the top surface 4a of the supporting portion 42, and the bottom surface 4b of the connecting portion 43 is located above the bottom surface 4b of the supporting portion 42. The thickness center of the connecting portion 43 and the thickness centers of the supporting portion 42 and the vibrating portion 41 are located on the same X-Z' plane. Therefore, the vibrating substrate 4 has a vertically symmetrical shape. This allows the vibrating element 3 to be mounted on the base 21 in either the upside or downside direction, making it easy to manufacture the vibrator 1.

[0021] As shown in FIG. 6, the support 42 is divided into two parts, a first support 421 and a second support 422 arranged in a line in the Z'-axis direction and spaced apart from each other. The first and second support parts 421 and 422 are arranged symmetrically with respect to a center line that passes through the center of the vibration part 41 and extends in the X-axis direction. The first support part 421 is joined to a joining member B1, and the second support part 422 is joined to a joining member B2. According to this configuration, the connecting part 43 is mainly deformed to move the first and second support parts 421 and 422 away from each other or closer to each other, so that the stress applied from the base 21 can be absorbed and relaxed more effectively. Therefore, the stress from the base 21 is less likely to be transmitted by the vibration part 41, and the fluctuation of the vibration characteristics can be effectively suppressed. Therefore, the vibration element 3 has excellent vibration characteristics.

[0022] Similarly, the connecting portion 43 is divided into two parts and has a first connecting portion 431 and a second connecting portion 432 that are arranged side by side in the Z'-axis direction and spaced apart from each other. The first connecting portion 431 connects the first support portion 421 and the vibrating portion 41, and the second connecting portion 432 connects the second support portion 422 and the vibrating portion 41. Further, the first and second connecting portions 431 and 432 are symmetrically arranged with respect to a center line that passes through the center of the vibrating portion 41 and extends in the X-axis direction. With such a configuration, the connecting portion 43 is more likely to be deformed, and the first and second support portions 421 and 422 are more likely to be separated or approximated. Therefore, the stress applied from the base 21 can be more effectively absorbed and relaxed. For this reason, the stress from the base 21 is less likely to be transmitted by the vibrating portion 41, and fluctuations in vibration characteristics can be effectively suppressed. Therefore, the vibration element 3 having excellent vibration characteristics is obtained.

[0023] In particular, the width W31 of the first connecting portion 431 is smaller than the width W21 of the first support portion 421. That is, W31 < W21. Similarly, the width W32 of the second connecting portion 432 is smaller than the width W22 of the second support portion 422. That is, W32 < W22. Thereby, the first and second connecting portions 431 and 432 that contact the root portions of the first and second support portions 421 and 422 become soft, respectively, and the first support portion 421 and the second support portion 422 are more likely to be separated or approximated. Therefore, the stress applied from the base 21 can be more effectively absorbed and relaxed. For this reason, the stress from the base 21 is less likely to be transmitted by the vibrating portion 41, and fluctuations in vibration characteristics can be effectively suppressed. Therefore, the vibration element 3 having excellent vibration characteristics is obtained.

[0024] As shown in Fig. 3, Fig. 4 and Fig. 5, the electrode layer 5 has a first excitation electrode 511 arranged on the upper surface 4a of the vibrating part 41, a second excitation electrode 521 arranged on the lower surface 4b of the vibrating part 41 so as to face the first excitation electrode 511, a first pad electrode 512 arranged on the first support part 421, a second pad electrode 522 arranged on the second support part 422, a first connection electrode 513 electrically connecting the first excitation electrode 511 and the first pad electrode 512, and a second connection electrode 523 electrically connecting the second excitation electrode 521 and the second pad electrode 522. The first pad electrode 512 is electrically connected to the internal terminal 241 via the bonding member B1, and the second pad electrode 522 is electrically connected to the internal terminal 242 via the bonding member B2. This electrically connects the package 2 and the vibration element 3.

[0025] Moreover, the first pad electrode 512 is formed on the entire surface of the first support portion 421, and the first connection electrode 513 is formed on the entire surface of the first coupling portion 431. Similarly, the second pad electrode 522 is formed on the entire surface of the second support portion 422, and the second connection electrode 523 is formed on the entire surface of the second coupling portion 432. However, the arrangement of the first and second pad electrodes 512, 522 and the first and second connection electrodes 513, 523 is not particularly limited.

[0026] Such an electrode layer 5 is formed by patterning a metal film formed on the surface of the vibration substrate 4 using photolithography and etching techniques. The configuration of the electrode layer 5 is not particularly limited as long as it has conductivity, but it can be configured, for example, as a laminate of a Cr (chromium) underlayer and a Au (gold) surface layer. The thickness of the electrode layer 5 is not particularly limited, but is about 3000 Å.

[0027] As described above, in the vibration element 3, the stress applied from the base 21 is absorbed and alleviated by making the connecting portion 43 thinner than the support portion 42 and the vibration portion 41, but the mechanical strength is accordingly reduced, and there is a risk of breakage due to impact. Therefore, the vibration element 3 further has a metal film 6 for reinforcing the connecting portion 43.

[0028] 2 to 5, the metal film 6 has a first metal film 61 disposed on the first connection electrode 513 located on the first connection portion 431 and reinforcing the first connection portion 431, and a second metal film 62 disposed on the second connection electrode 523 located on the second connection portion 432 and reinforcing the second connection portion 432. This increases the strength of the connection portion 43 and improves the impact resistance of the vibration element 3. In addition, by making the connection portion 43 thin and using the first and second metal films 61 and 62 to compensate for the insufficient strength, the toughness of the connection portion 43 is increased, and it is possible to achieve a good balance between absorbing and mitigating stress and ensuring mechanical strength.

[0029] In this embodiment, the metal film 6 is disposed directly on the first and second connection electrodes 513, 514 located at the first and second coupling portions 431, 432, but is not limited thereto. In other words, the metal film 6 may be disposed between the first and second connection electrodes 513, 514 and another metal layer therebetween. In other words, it is sufficient that the metal film 6 is disposed in an upper layer of the first and second connection electrodes 513, 514 located at the first and second coupling portions 431, 432.

[0030] Moreover, the first metal film 61 covers the entire surface of the first connecting portion 431. This allows the first connecting portion 431 to be effectively reinforced. Moreover, the first metal film 61 is formed across the first connecting portion 431 and the first support portion 421. Moreover, the first metal film 61 is formed across the first connecting portion 431 and the vibrating portion 41. This allows the boundary portion between the first connecting portion 431 and the first support portion 421 and the boundary portion between the first connecting portion 431 and the vibrating portion 41, which are locations where stress is likely to concentrate, to be covered with the first metal film 61, improving the mechanical strength of the relevant portions.

[0031] Moreover, the second metal film 62 covers the entire surface of the second connecting portion 432. This allows the second connecting portion 432 to be effectively reinforced. Moreover, the second metal film 62 is formed across the second connecting portion 432 and the second supporting portion 422. Moreover, the second metal film 62 is formed across the second connecting portion 432 and the vibrating portion 41. As a result, the boundary between the second connecting portion 432 and the second supporting portion 422 and the boundary between the second connecting portion 432 and the vibrating portion 41, which are places where stress is likely to concentrate, are covered with the second metal film 62, improving the mechanical strength of those portions.

[0032] The thickness t6 of the first and second metal films 61, 62 is larger than the thickness t5 of the electrode layer 5. That is, t6>t5. The thicknesses t6, t5 refer to average thicknesses. This allows the first and second metal films 61, 62 to effectively reinforce the connecting portion 43. The thickness t6 is not particularly limited and varies depending on the dimensions of the vibration substrate 4, but is preferably, for example, 5 μm or more and 50 μm or less. This makes the first and second metal films 61, 62 sufficiently thick, and the reinforcing effect of the vibration substrate 4 becomes more pronounced.

[0033] The first and second metal films 61, 62 are not particularly limited to a specific material, but in this embodiment, they are made of nickel (Ni). This provides the first and second metal films 61, 62 with high strength. Furthermore, by using a plating method, the first and second metal films 61, 62 can be easily formed to be thick.

[0034] The configuration of the vibration element 3 has been described above. However, the configuration of the vibration element 3 is not particularly limited, and may be, for example, the configurations shown in Figures 7 to 10. For convenience of explanation, the electrode layer 5 and the metal film 6 are omitted in Figures 7 to 10.

[0035] For example, in this embodiment, the first connecting portion 431 is positioned biased toward the outer edge of the vibration substrate 4 relative to the first support portion 421, and the second connecting portion 432 is positioned biased toward the outer edge of the vibration substrate 4 relative to the second support portion 422, but this is not limited to this, and as shown in Figure 7, the first connecting portion 431 may be positioned biased toward the inner side of the vibration substrate 4 relative to the first support portion 421, and the second connecting portion 432 may be positioned biased toward the inner side of the vibration substrate 4 relative to the second support portion 422.

[0036] 8, the width of the first connecting portion 431 may be equal to the width of the first supporting portion 421, and the width of the second connecting portion 432 may be equal to the width of the second supporting portion 422. As shown in Fig. 9, the first and second connecting portions 431, 432 may be formed in plurality and aligned in the Z'-axis direction. As shown in Fig. 10, the first and second connecting portions 431, 432 may be bent or curved one or more times along the way.

[0037] Next, a manufacturing method of the vibration element 3 will be described. First, as shown in FIG. 11, an AT-cut quartz crystal substrate 400, which is a base material of the vibration substrate 4, is prepared. The quartz crystal substrate 400 is larger than the vibration substrate 4, and a plurality of vibration substrates 4 can be formed from the quartz crystal substrate 400. Next, as shown in FIG. 12, the quartz crystal substrate 400 is patterned using a photolithography technique and an etching technique to form the vibration substrate 4. Next, as shown in FIG. 13, an electrode layer 5 is formed on the vibration substrate 4. The electrode layer 5 can be formed by forming a metal film on the surface of the vibration substrate 4 and patterning the formed metal film using a photolithography technique and an etching technique. Next, as shown in FIG. 14, a mask M is formed on the vibration substrate 4, which opens the areas where the first and second metal films 61 and 62 are to be formed. Next, as shown in FIG. 15, a metal film 6 is formed on the surface of the vibration substrate 4 by electroless plating. Finally, as shown in FIG. 16, the mask M is removed. As a result, the vibration element 3 is obtained. According to such a manufacturing method, the vibration element 3 can be easily manufactured.

[0038] The above has described the vibrator 1. As described above, the vibration element 3 of such a vibrator 1 is in the form of a plate having an upper surface 4a, which is a first surface, and a lower surface 4b, which is a second surface, which are in a front-back relationship, and includes a vibration substrate 4 having a vibration section 41, a support section 42, and a connecting section 43 that connects the vibration section 41 and the support section 42 and has a portion that is thinner than the support section 42, a first excitation electrode 511 arranged on the upper surface 4a of the vibration section 41, a second excitation electrode 521 arranged on the lower surface 4b of the vibration section 41, a first pad electrode 512 arranged on the support section 42, and a second excitation electrode 521 arranged on the support section 42. The electrode layer 5 has a second pad electrode 522 that is connected to the first excitation electrode 511 and the first pad electrode 512, a first connection electrode 513 that is arranged on the connecting portion 43 and connects the first excitation electrode 511 and the first pad electrode 512, and a second connection electrode 523 that is arranged on the connecting portion 43 and connects the second excitation electrode 521 and the second pad electrode 522, a first metal film 61 that is arranged on the upper layer of the first connection electrode 513 located on the connecting portion 43 and has a thickness larger than that of the electrode layer 5, and a second metal film 62 that is arranged on the upper layer of the second connection electrode 523 located on the connecting portion 43 and has a thickness larger than that of the electrode layer 5. With this configuration, the connecting portion 43 becomes easily deformed, and the stress applied from the base 21 can be effectively absorbed and relaxed. Therefore, the stress is not easily transmitted to the vibration portion 41, and the fluctuation of the vibration characteristics caused by the stress can be effectively suppressed. Therefore, the vibration element 3 has excellent vibration characteristics. Furthermore, by arranging the first and second metal films 61, 62 on the connecting portion 43, the connecting portion 43 is reinforced, and the vibration element 3 has excellent impact resistance.

[0039] As described above, the first metal film 61 and the second metal film 62 are disposed across the connecting portion 43 and the supporting portion 42, respectively. With this configuration, the boundary between the connecting portion 43 and the supporting portion 42, where stress is likely to concentrate, is covered with the first and second metal films 61, 62, improving the mechanical strength of that portion.

[0040] As described above, the first metal film 61 and the second metal film 62 are disposed across the connecting portion 43 and the vibrating portion 41, respectively. With this configuration, the boundary between the connecting portion 43 and the vibrating portion 41, where stress is likely to concentrate, is covered with the first and second metal films 61, 62, improving the mechanical strength of that portion.

[0041] As described above, the connecting portion 43 has a portion that is thinner than the vibrating portion 41. With this configuration, the connecting portion 43 becomes easier to deform, and can effectively absorb and reduce the stress applied from the base 21. Therefore, the stress is less likely to be transmitted to the vibrating portion 41, and fluctuations in vibration characteristics caused by the stress can be effectively suppressed.

[0042] As described above, the support portion 42 has the first support portion 421 and the second support portion 422 that are spaced apart from each other, the first pad electrode 512 is disposed on the first support portion 421, and the second pad electrode 522 is disposed on the second support portion 422. As a result, the first and second support portions 421, 422 are spaced apart or close to each other, so that the stress applied from the base 21 can be more effectively absorbed and alleviated. Therefore, the stress from the base 21 is less likely to be transmitted by the vibrating portion 41, and fluctuations in vibration characteristics can be effectively suppressed.

[0043] As described above, the connecting portion 43 has the first connecting portion 431 that connects the first support portion 421 and the vibration portion 41, and the second connecting portion 432 that connects the second support portion 422 and the vibration portion 41. This makes it easier for the connecting portion 43 to deform, and makes it easier for the first and second support portions 421, 422 to move apart or approach each other. Therefore, the stress applied from the base 21 can be absorbed and alleviated more effectively.

[0044] As described above, the first connecting portion 431 is narrower than the first supporting portion 421, and the second connecting portion 432 is narrower than the second supporting portion 422. This makes the first and second connecting portions 431 and 432 softer, and makes it easier for the first supporting portion 421 and the second supporting portion 422 to move apart or approach each other. Therefore, the stress applied from the base 21 can be absorbed and alleviated more effectively.

[0045] <Second embodiment> Fig. 17 and Fig. 18 are cross-sectional views showing a vibration element according to a second embodiment of the present invention, respectively. Fig. 17 is a cross-sectional view taken along line AA in Fig. 2, and Fig. 18 is a cross-sectional view taken along line BB in Fig. 2.

[0046] The vibration element 3 according to this embodiment is similar to the vibration element 3 according to the first embodiment, except that the first metal film 61 and the second metal film 62 are formed on the entire side and upper and lower surfaces of the first and second support parts 421 and 422, and that the vibration element 3 according to this embodiment has a third metal film 63 and a fourth metal film 64. In the following description, the vibration element 3 according to this embodiment will be described with a focus on the differences from the first embodiment, and the description of the same points will be omitted. In addition, in each drawing of this embodiment, the same reference numerals are used for the same configurations as those in the above-mentioned embodiment.

[0047] 17 and 18, a first metal film 61 is further formed on the entire side surface and upper and lower surfaces of the first support portion 421. Specifically, the first metal film 61 is formed on the side surface located on the negative side in the X-axis direction of the first support portion 421, the upper surface 4a of the first support portion 421, and the lower surface 4b of the first support portion 421, via a first pad electrode 512.

[0048] 17 and 18, the second metal film 62 is formed on the entire side surface and upper and lower surfaces of the second support portion 422. Specifically, the second metal film 62 is formed on the side surface located on the negative side in the X-axis direction of the second support portion 422, the upper surface 4a of the first support portion 422, and the lower surface 4b of the second support portion 422, via the second pad electrode 522.

[0049] Moreover, the vibration element 3 shown in FIG. 17 and FIG. 18 has a third metal film 63 arranged on the first metal film 61 and a fourth metal film 64 arranged on the second metal film 62. With these configurations, the support portion 42 can be reinforced more effectively. The third metal film 63 and the fourth metal film 64 are not particularly limited, but are made of Au (gold) in this embodiment. This makes it possible to suppress corrosion and oxidation of the first and second metal films 61 and 62. In addition, they are compatible with the gold bumps used as the bonding members B1 and B2, and the vibration element 3 can be bonded more firmly to the base 21.

[0050] In this embodiment, the third metal film 63 is disposed directly on the first metal film 61, and the fourth metal film 64 is disposed directly on the second metal film 62, but this is not limited to the above. That is, the third metal film 63 may be disposed on the first metal film 61 via another metal layer, and the fourth metal film 64 may be disposed on the second metal film 62 via another metal layer. In other words, it is sufficient that the third metal film 63 is disposed in an upper layer above the first metal film 61, and it is sufficient that the fourth metal film 64 is disposed in an upper layer above the second metal film 62.

[0051] As described above, the vibration element 3 of this embodiment has the third metal film 63 disposed on the upper layer of the first metal film 61, and the fourth metal film 64 disposed on the upper layer of the second metal film 62. This makes it possible to more effectively reinforce the support portion 42. In particular, by forming the third metal film 63 and the fourth metal film 64 from Au (gold), it is possible to suppress corrosion and oxidation of the first and second metal films 61 and 62. In addition, this has good compatibility with the gold bumps used as the bonding members B1 and B2, and the vibration element 3 can be bonded more firmly to the base 21.

[0052] The second embodiment as described above can also achieve the same effects as the first embodiment described above.

[0053] <Third embodiment> Fig. 19 and Fig. 20 are cross-sectional views showing a vibration element according to a third embodiment of the present invention, respectively. Fig. 19 is a cross-sectional view taken along line AA in Fig. 2, and Fig. 20 is a cross-sectional view taken along line BB in Fig. 2.

[0054] The vibration element 3 according to this embodiment is similar to the vibration element 3 according to the first embodiment described above, except that the shape of the vibration substrate 4 is different. In the following description, the vibration element 3 according to this embodiment will be described with a focus on the differences from the first embodiment described above, and a description of the similar points will be omitted. In addition, in each drawing of this embodiment, the same reference numerals are used for the same configurations as those in the above-mentioned embodiment.

[0055] The vibration element 3 shown in FIG. 19 and FIG. 20 is configured such that the lower surface 4b of the connecting portion 43, the lower surface 4b of the support portion 42, and the lower surface 4b of the vibration portion 41 are continuous flat surfaces. The first metal film 61 is disposed on the lower surface 4b of the second connecting portion 431, and the second metal film 62 is disposed on the lower surface 4b of the second connecting portion 432. In other words, the first and second metal films 61 and 62 are not disposed on the upper surface 4a or side surface of the connecting portion 43. With this configuration, the first and second metal films 61 and 62 can be formed before the outer shape of the vibration substrate 4 is formed. Therefore, the accuracy of forming the first and second metal films 61 and 62 is improved.

[0056] In addition, in this embodiment, the first metal film 61 and the second metal film 62 are disposed on a part of the lower surface 4b of the first and second support parts 421, 422, but are not limited to this. In other words, the first metal film 61 and the second metal film 62 may be disposed on the entire lower surface 4b of the first and second support parts 421, 422. This can improve the mechanical strength of the boundary parts between the first and second connection parts 431, 432 and the first and second support parts 421, 422, which are locations where stress is likely to concentrate.

[0057] In this embodiment, the first metal film 61 and the second metal film 62 are disposed on both the upper surface 4a and the lower surface 4a of the first and second connecting parts 431 and 432, but are not limited to this. In other words, the first metal film 61 and the second metal film 62 may be disposed on only one of the upper surface 4a and the lower surface 4a of the first and second connecting parts 431 and 432. In this case, the first metal film 61 and the second metal film 62 may be disposed on the entirety of one of the upper surface 4a and the lower surface 4b of the first and second supporting parts 421 and 422.

[0058] As described above, in the vibration element 3 of this embodiment, the lower surface 4b of the connecting portion 43, the lower surface 4b of the support portion 42, and the lower surface 4b of the vibration portion 41 are continuous flat surfaces, and the first metal film 61 and the second metal film 62 are disposed on the lower surface 4b side. This allows the first and second metal films 61, 62 to be formed before the outer shape of the vibration substrate 4 is formed. Therefore, the accuracy of forming the first and second metal films 61, 62 is improved.

[0059] The third embodiment as described above can also achieve the same effects as the first embodiment described above.

[0060] <Fourth embodiment> Fig. 21 is a plan view showing a vibration element according to a fourth embodiment of the present invention. For the sake of convenience, the metal film 6 is omitted in Fig. 21.

[0061] The vibration element 3 according to this embodiment is similar to the vibration element 3 according to the first embodiment described above, except that the shape of the vibration substrate 4, particularly the shape of the connecting portion 43, is different. In the following description, the vibration element 3 according to this embodiment will be described with a focus on the differences from the first embodiment described above, and description of similar points will be omitted. In addition, in each drawing of this embodiment, the same reference numerals are used for configurations similar to those of the above-mentioned embodiment.

[0062] In the vibration element 3 shown in FIG. 21, the connecting portion 43 has a first partitioning portion 43a located between the support portion 42 and the vibration portion 41 and separating them, and a second partitioning portion 43b located between the first support portion 421 and the second support portion 422 and separating them. The first partitioning portion 43a extends in the Z'-axis direction, and the second partitioning portion 43b extends in the X-axis direction and has one end connected to the first partitioning portion 43a. Therefore, the connecting portion 43 is T-shaped. According to this configuration, compared to the configuration of the first embodiment described above, the first and second support portions 421 and 422 are less likely to approach or separate from each other, but the mechanical strength of the vibration substrate 4 can be increased.

[0063] As described above, in the vibration element 3 of this embodiment, the support portion 42 has the first support portion 421 on which the first pad electrode 512 is arranged and the second support portion 422 on which the second pad electrode 522 is arranged, and the connecting portion 43 has the first partition portion 43a located between the support portion 42 and the vibration portion 41 and separating the support portion 42 and the vibration portion 41, and the second partition portion 43b located between the first support portion 421 and the second support portion 422 and separating the first support portion 421 and the second support portion 422. According to this configuration, compared to the configuration of the first embodiment described above, the first and second support portions 421 and 422 are less likely to approach or separate from each other, but the mechanical strength of the vibration substrate 4 can be increased.

[0064] The fourth embodiment as described above can also achieve the same effects as the first embodiment described above.

[0065] Although the vibration element of the present invention has been described above based on the illustrated embodiment, the present invention is not limited thereto, and the configuration of each part can be replaced with any configuration having a similar function. In addition, any other configuration may be added to the present invention. In addition, the present invention may be a combination of any two or more configurations of the above-mentioned embodiments.

[0066] In the above-described embodiment, the support portion 42 is divided into the first and second support portions 421 and 422, but this is not limited thereto. In other words, the first and second pad electrodes 512 and 522 may be disposed together on one support portion 42.

[0067] In addition, in the above-described embodiment, the vibration element 3 is applied to the vibrator 1, but this is not limited to this, and it can also be applied to an oscillator in which an oscillation circuit that oscillates the vibration element 3 is implemented within the package 2. [Explanation of symbols]

[0068] 1...vibrator, 2...package, 21...base, 211...recess, 22...lid, 23...sealing member, 241...internal terminal, 242...internal terminal, 251...external terminal, 252...external terminal, 3...vibration element, 4...vibration substrate, 4a...upper surface, 4b...lower surface, 400...quartz substrate, 41...vibration portion, 42...support portion, 421...first support portion, 422...second support portion, 43...connection portion, 43a...first partition portion, 43b...second partition portion, 431...first connection portion, 432...second connection portion, 5...electrode layer, 511...first excitation electrode, 512...first pad electrode, 513...first connection electrode, 521...second excitation electrode, 522...second pad electrode, 523...second connection electrode, 6...metal film, 61...first metal film, 62...second metal film, 63...third metal film, 64...fourth metal film, B1...joining member, B2...joining member, M...mask, S...accommodation space, t1...thickness, t2...thickness, t3...thickness, t5...thickness, t6...thickness, W21...width, W22...width, W31...width, W32...width

Claims

1. a vibration substrate having a plate shape with a first surface and a second surface which are in a front-back relationship, the vibration substrate having a vibration section, a support section, and a connecting section which connects the vibration section and the support section and has a portion having a thickness smaller than that of the support section; an electrode layer including a first excitation electrode disposed on the first surface of the vibration section, a second excitation electrode disposed on the second surface of the vibration section, a first pad electrode disposed on the support section, a second pad electrode disposed on the support section, a first connection electrode disposed on the connecting section and connecting the first excitation electrode and the first pad electrode, and a second connection electrode disposed on the connecting section and connecting the second excitation electrode and the second pad electrode; a first metal film disposed on the first connection electrode located at the coupling portion and having a thickness greater than that of the electrode layer; A vibration element comprising: a second metal film arranged on an upper layer of the second connection electrode located at the connecting portion, the second metal film being thicker than the electrode layer.

2. The vibration element according to claim 1 , wherein the first metal film and the second metal film are disposed across the connecting portion and the supporting portion, respectively.

3. The vibration element according to claim 2 , wherein the first metal film and the second metal film are disposed across the connecting portion and the vibration portion, respectively.

4. The vibration element according to claim 1 , wherein the connecting portion has a portion having a thickness smaller than that of the vibration portion.

5. the support portion includes a first support portion on which the first pad electrode is disposed and a second support portion on which the second pad electrode is disposed, The vibration element described in claim 1, wherein the connecting portion has a first partition portion located between the support portion and the vibration portion and separating the support portion and the vibration portion, and a second partition portion located between the first support portion and the second support portion and separating the first support portion and the second support portion.

6. The support portion includes a first support portion and a second support portion that are spaced apart from each other, the first pad electrode is disposed on the first support portion, The vibration element according to claim 1 , wherein the second pad electrode is disposed on the second support portion.

7. The vibration element according to claim 6 , wherein the connecting portion has a first connecting portion that connects the first support portion and the vibration portion, and a second connecting portion that connects the second support portion and the vibration portion.

8. The first connecting portion has a width narrower than that of the first supporting portion, The vibration element according to claim 7 , wherein the second connecting portion has a width narrower than that of the second supporting portion.

9. the second surface of the connecting portion, the second surface of the supporting portion, and the second surface of the vibrating portion are continuous flat surfaces, The vibration element according to claim 1 , wherein the first metal film and the second metal film are disposed on the second surface side.

10. a third metal film disposed on an upper layer of the first metal film; The vibration element according to claim 1 , further comprising: a fourth metal film disposed on an upper layer of the second metal film.

Images