Vibration device

Abstract

To provide a vibration device that has excellent vibration characteristics.SOLUTION: A vibration device has: a base that has a first surface and a second surface in the front and back relationship; a vibration element that is located on the first surface side with respect to the base and includes a vibration substrate and an electrode; a conductive layer that is arranged on the first surface; a metal bump that is arranged between the base and the vibration element, and joins the base and the vibration element to each other and electrically connects the conductive layer and the electrode to each other; and at least one of a first low elastic modulus layer that is interposed between the base and the conductive layer, overlaps the metal bump in plan view of the base, and has a smaller modulus of elasticity than that of the metal bump, and a second low elastic modulus layer that is interposed between the vibration substrate and the electrode, overlaps the metal bump in plan view of the base, and has a smaller modulus of elasticity than that of the metal bump.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a quartz crystal resonator as a resonator device in which a quartz crystal resonator element is fixed to a package via metal bumps. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-127469 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because metal bumps have a high elastic modulus (Young's modulus) and are hard, they are prone to plastic deformation due to, for example, thermal stress caused by the difference in the linear expansion coefficient between the crystal resonator element and the package. If the metal bumps undergo plastic deformation, unwanted vibrations and frequency hysteresis may occur in the crystal resonator element, deteriorating the vibration characteristics. [Means for solving the problem]

[0005] The vibration device of the present invention comprises a base having a first surface and a second surface which are opposite surfaces, a vibration element located on the first surface side of the base and including a vibration substrate and an electrode arranged on the base side surface of the vibration substrate, a conductive layer arranged on the first surface, a metal bump arranged between the base and the vibration element, joining the base and the vibration element and electrically connecting the conductive layer and the electrode, and at least one of a first low elastic modulus layer interposed between the base and the conductive layer, overlapping the metal bump in a planar view of the base, and having a modulus of elasticity smaller than that of the metal bump, and a second low elastic modulus layer interposed between the vibration substrate and the electrode, overlapping the metal bump in a planar view of the base, and having a modulus of elasticity smaller than that of the metal bump. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a cross-sectional view showing a vibration device according to a first embodiment. [Figure 2] FIG. 2 is a plan view showing the top surface of the base. [Figure 3] FIG. 3 is a cross-sectional view taken along line BB in FIG. 2. [Figure 4] FIG. 10 is a cross-sectional view showing a modified example. [Figure 5] FIG. 2 is a plan view showing a vibration element. [Figure 6] FIG. 4 is a cross-sectional view showing a vibration device according to a second embodiment. [Figure 7] FIG. 10 is a cross-sectional view showing a modified example. [Figure 8] FIG. 10 is a cross-sectional view showing a vibration device according to a third embodiment. [Figure 9] 1 is a graph showing the relationship between Young's modulus ratio and stress ratio. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, preferred embodiments of the vibration device will be described with reference to the accompanying drawings. For ease of explanation, the upper side of the paper in Figures 1, 3, 4, 6, 7, and 8 will also be referred to as "top," and the lower side of the paper will also be referred to as "bottom." Furthermore, the front side of the paper in Figures 2 and 5 will also be referred to as "top," and the back side of the paper will also be referred to as "bottom."

[0008] First Embodiment FIG. 1 is a cross-sectional view showing a vibration device according to a first embodiment. FIG. 2 is a plan view showing the upper surface of a base. FIG. 3 is a cross-sectional view taken along line BB in FIG. 2. FIG. 4 is a cross-sectional view showing a modified example. FIG. 5 is a plan view showing a vibration element. Note that FIG. 1 is a cross-sectional view taken along line AA in FIG. 2.

[0009] 1 includes a package 10 having a housing portion S, and a vibration element 4 housed in the housing portion S. The package 10 also includes a base 2 to which the vibration element 4 is bonded via a pair of metal bumps 81 and 82, and a lid 3 that covers the vibration element 4 and is bonded to an upper surface 2a of the base 2. An integrated circuit 6 including an oscillation circuit 6A is also formed on the base 2.

[0010] The base 2 is a silicon substrate, particularly a P-type silicon substrate. However, the base 2 is not particularly limited and may be an N-type silicon substrate. Also, a semiconductor substrate other than silicon, such as a semiconductor substrate of Ge, GaP, GaAs, or InP, may be used, or a substrate other than a semiconductor substrate, such as a ceramic substrate, may be used.

[0011] As shown in FIG. 1, the base 2 is plate-shaped and has an upper surface 2a as a first surface and a lower surface 2b as a second surface, which are opposite surfaces. An insulating film 20 is formed on the surface of the base 2. An integrated circuit 6 electrically connected to the vibration element 4 is formed on the lower surface 2b of the base 2. By forming the integrated circuit 6 on the base 2, the base 2 can be used more effectively. In particular, by forming the integrated circuit 6 on the lower surface 2b, there is no bonding area with the lid 3, so a larger space can be secured for forming the integrated circuit 6 compared to when the integrated circuit 6 is formed on the upper surface 2a. However, the integrated circuit 6 may be formed on the upper surface 2a of the base 2 instead of the lower surface 2b. The integrated circuit 6 may also be omitted.

[0012] The integrated circuit 6 includes an oscillator circuit 6A that is electrically connected to the vibrating element 4 and that oscillates the vibrating element 4 to generate an oscillation signal such as a clock signal. The integrated circuit 6 may include other circuits in addition to the oscillator circuit 6A. An example of such a circuit is a processing circuit that processes an output signal from the oscillator circuit 6A, and an example of such a processing circuit is a PLL circuit.

[0013] A laminate 60 is formed on the lower surface 2b, and is formed by laminating a wiring layer 62, an insulating layer 63, a passivation film 64, and a terminal layer 65. A plurality of active elements (not shown) formed on the lower surface 2b are electrically connected via wiring included in the wiring layer 62 to form the integrated circuit 6. The terminal layer 65 also has a plurality of mounting terminals 651 electrically connected to the oscillator circuit 6A. While the illustrated configuration shows a single wiring layer 62 in the laminate 60, this is not limiting, and multiple wiring layers 62 may be laminated with insulating layers 63 interposed therebetween. In other words, the wiring layers 62 and the insulating layers 63 may be alternately laminated multiple times. This, for example, can increase the flexibility in routing the wiring within the circuit and in arranging the multiple mounting terminals 651.

[0014] The base 2 is also formed with a pair of through holes 21, 22 that penetrate the base 2 in the thickness direction. A conductive material is filled inside each of the through holes 21, 22, and through electrodes 210, 220 are formed therein. As shown in FIGS. 1 and 2, a pair of wirings 28, 29 are arranged on the upper surface 2a of the base 2 as a conductive layer electrically connected to the vibration element 4. The wiring 28 is electrically connected to the oscillation circuit 6A via the through electrode 210, and the wiring 29 is electrically connected to the oscillation circuit 6A via the through electrode 220.

[0015] In addition, first low elastic modulus layers 51 and 52 are disposed on the upper surface 2a of the base 2. The elastic modulus of these first low elastic modulus layers 51 and 52 is smaller than that of the metal bumps 81 and 82. Therefore, the first low elastic modulus layers 51 and 52 are softer than the metal bumps 81 and 82. Note that the "elastic modulus" refers to Young's modulus. The elastic modulus of the first low elastic modulus layers 51 and 52 is preferably 1 / 10 or less, more preferably 1 / 50 or less, and even more preferably 1 / 100 or less of that of the metal bumps 81 and 82.

[0016] A more detailed description will be given with reference to the graph shown in FIG. 9. In the graph shown in FIG. 9, the horizontal axis indicates the Young's modulus ratio, and the vertical axis indicates the stress ratio of the vibrating portion. The graph shown in FIG. 9 shows a case where a low elastic modulus layer is arranged on the base 2 side, and a case where a low elastic modulus layer is arranged on the vibrator side. The low elastic modulus layer corresponds to the first low elastic modulus layers 51 and 52. The vibrating portion corresponds to the vibrating element 4.

[0017] In addition, the graph shown in Figure 9 plots the change in stress when the metal bumps 81 and 82 are made of gold (Au), the elastic modulus of the low elastic modulus layer is the same as that of the metal bumps 81 and 82 (horizontal axis = 1), and the stress generated in the vibrating part is set to 1 (vertical axis = 1).

[0018] When the first low elastic modulus layers 51 and 52 are disposed on the upper surface of the base 2 (described as "base side" in FIG. 9) as in this embodiment, the above-mentioned preferable numerical range can be obtained.

[0019] The material of the first low elastic modulus layers 51, 52 is not particularly limited as long as it has a lower elastic modulus than the metal bumps 81, 82. For example, a resin material is preferable. That is, the first low elastic modulus layers 51, 52 are preferably formed containing a resin material. This allows the first low elastic modulus layers 51, 52 to be sufficiently soft with respect to the metal bumps 81, 82. Furthermore, among resin materials, a photosensitive resin material, such as an ultraviolet-curable resin, is particularly preferable. This enables microfabrication of the first low elastic modulus layers 51, 52, allowing for accurate formation of the first low elastic modulus layers 51, 52 and miniaturization of the resonator device 1. Furthermore, since the first low elastic modulus layers 51, 52 can be formed using a semiconductor process, the resonator device 1 can be efficiently manufactured. In this embodiment, the first low elastic modulus layers 51, 52 are made of an epoxy resin. This allows the first low elastic modulus layers 51, 52 to have appropriate flexibility. In addition to epoxy resin, polyimide resin or phenolic resin (a thermosetting resin material) may also be used. Additives such as metal fillers may be mixed into the resin material for the purpose of adjusting the linear expansion coefficient, imparting conductivity, or other purposes.

[0020] As shown in FIG. 3 , the entire surface of the first low elastic modulus layer 51, i.e., the top surface and side surfaces, is covered with wiring 28. Similarly, the entire surface of the first low elastic modulus layer 52, i.e., the top surface and side surfaces, is covered with wiring 29. By covering the first low elastic modulus layers 51 and 52 with the wiring 28 and 29 in this way, gas (outgassing) generated from the first low elastic modulus layers 51 and 52 can be confined within the wiring 28 and 29, and the gas can be prevented from being released into the housing section S. Therefore, for example, it is possible to prevent changes or deterioration in the vibration characteristics of the vibration element 4 due to contamination of the atmosphere in the housing section S caused by gas, pressure changes, etc. This results in a vibration device 1 with excellent reliability.

[0021] In the present embodiment, the first low elastic modulus layers 51, 52 are disposed on the upper surface 2a of the base 2, but the present invention is not limited to this, and another layer may be interposed between the first low elastic modulus layers 51, 52 and the base 2. For example, as shown in Fig. 4, the wirings 28, 29 may have a two-layer structure of lower layers 281, 291 and upper layers 282, 292, with the lower layers 281, 291 disposed on the upper surface 2a, the first low elastic modulus layers 51, 52 disposed on the lower layers 281, 291, and the upper layers 282, 292 disposed thereon to cover the first low elastic modulus layers 51, 52.

[0022] The lid 3 is a silicon substrate, just like the base 2. This makes the linear expansion coefficients of the base 2 and the lid 3 equal, suppressing the generation of thermal stress due to thermal expansion, resulting in a resonator device 1 with excellent vibration characteristics. Furthermore, since the resonator device 1 can be formed by a semiconductor process, the resonator device 1 can be manufactured with high precision and can be made smaller. However, the lid 3 is not particularly limited, and a semiconductor substrate other than silicon, such as a semiconductor substrate of Ge, GaP, GaAs, or InP, may also be used. Furthermore, a substrate other than a semiconductor substrate, such as a metal substrate such as Kovar, or a glass substrate, may also be used.

[0023] As shown in FIG. 1, the lid 3 has an opening on its lower surface and a bottomed recess 31 for accommodating the vibration element 4 therein. The lid 3 is directly bonded at its lower surface to the upper surface 2a of the base 2 via a bonding member 7. This forms an accommodating section S, which is a space for accommodating the vibration element 4, between the lid 3 and the base 2. In this embodiment, the lid 3 and the base 2 are bonded using diffusion bonding, which utilizes the diffusion between metals, among other direct bonding methods. However, the method for bonding the lid 3 and the base 2 is not particularly limited.

[0024] The housing section S is airtight and in a reduced pressure state, preferably a state closer to a vacuum, which reduces viscous resistance and improves the oscillation characteristics of the vibration element 4. However, the atmosphere in the housing section S is not particularly limited, and may be, for example, an atmosphere filled with an inert gas such as nitrogen or Ar, or may be in an atmospheric pressure state or a pressurized state instead of a reduced pressure state.

[0025] As shown in FIG. 5, the vibration element 4 includes a vibration substrate 41 and an electrode 42 disposed on the surface of the vibration substrate 41. The vibration substrate 41 has a thickness-shear vibration mode and is formed of an AT-cut quartz crystal substrate in this embodiment. The AT-cut quartz crystal substrate has a third-order frequency-temperature characteristic, which provides the vibration element 4 with excellent temperature characteristics. The electrode 42 includes an excitation electrode 421 disposed on the upper surface of the vibration substrate 41 and an excitation electrode 422 disposed on the lower surface opposite the excitation electrode 421. The electrode 42 also includes a pair of terminals 423 and 424 disposed on the lower surface of the vibration substrate 41, a wiring 425 electrically connecting the terminal 423 and the excitation electrode 421, and a wiring 426 electrically connecting the terminal 424 and the excitation electrode 422.

[0026] The configuration of the vibration element 4 is not limited to the above-described configuration. For example, the vibration element 4 may be a mesa type in which the vibration region sandwiched between the excitation electrodes 421 and 422 protrudes from its surroundings, or conversely, may be an inverted mesa type in which the vibration region is recessed from its surroundings. In addition, the vibration substrate 41 may be subjected to bevel processing in which the periphery is ground, or convex processing in which the upper and lower surfaces are made convex.

[0027] Furthermore, the vibration element 4 is not limited to one that vibrates in a thickness-shear vibration mode, and may be, for example, a tuning-fork type vibration element in which multiple vibrating arms vibrate in an in-plane flexural direction. In other words, the vibration substrate 41 is not limited to one formed from an AT-cut quartz crystal substrate, and may be formed from a quartz crystal substrate other than an AT-cut quartz crystal substrate, such as an X-cut quartz crystal substrate, a Y-cut quartz crystal substrate, a Z-cut quartz crystal substrate, a BT-cut quartz crystal substrate, an SC-cut quartz crystal substrate, or an ST-cut quartz crystal substrate.

[0028] Furthermore, the constituent material of the vibration substrate 41 is not limited to quartz crystal, and may be, for example, a piezoelectric single crystal such as lithium niobate, lithium tantalate, lithium tetraborate, langasite, potassium niobate, gallium phosphate, or other piezoelectric single crystals. Furthermore, the vibration element 4 is not limited to a piezoelectrically driven vibrating piece, but may be an electrostatically driven vibrating piece using electrostatic force.

[0029] 3, the vibration element 4 as described above is joined to the base 2 by a pair of metal bumps 81 and 82 and is electrically connected to the wirings 28 and 29. The metal bumps 81 and 82 are stud bumps, plated bumps, or the like.

[0030] The metal bump 81 is disposed on a portion of the wiring 28 that is located on the first low elastic modulus layer 51. That is, the metal bump 81 is disposed on the wiring 28 so as to overlap the first low elastic modulus layer 51 in a plan view of the base 2. The metal bump 81 is bonded to the wiring 28 on its lower surface and to the terminal 423 on its upper surface. As a result, the metal bump 81 bonds the vibration element 4 and the base 2, and electrically connects the wiring 28 and the terminal 423. Similarly, the metal bump 82 is disposed on a portion of the wiring 29 that is located on the first low elastic modulus layer 52. That is, the metal bump 82 is disposed on the wiring 29 so as to overlap the first low elastic modulus layer 52 in a plan view of the base 2. The metal bump 82 is bonded to the wiring 29 on its lower surface and to the terminal 424 on its upper surface. As a result, the vibration element 4 and the base 2 are joined by the metal bumps 82, and the wiring 29 and the terminals 424 are electrically connected.

[0031] These metal bumps 81 and 82 are bonded to the wirings 28 and 29 by ultrasonic bonding, and are bonded to the terminals 423 and 424 by thermocompression bonding. However, the bonding method is not particularly limited.

[0032] Such metal bumps 81, 82 are not particularly limited, and may be, for example, gold bumps, silver bumps, copper bumps, solder bumps, etc. The constituent material of the metal bumps 81, 82 is preferably the same as the material of the outermost layer of the wirings 28, 29 and the material of the outermost layer of the terminals 423, 424. For example, if the outermost layers of the wirings 28, 29 and the terminals 423, 424 are made of gold (Au), the metal bumps 81, 82 are preferably gold bumps. This increases the affinity between the wirings 28, 29 and the terminals 423, 424 and the metal bumps 81, 82, and provides high bonding strength.

[0033] In this way, by using the metal bumps 81 and 82 to bond the vibration element 4 and the base 2, the vibration device 1 can be miniaturized. Simply put, if a paste-like conductive adhesive were used instead of the metal bumps 81 and 82 to bond them, the diameter of the conductive adhesive would expand when the conductive adhesive was applied to the base 2 or when the vibration element 4 was pressed against the conductive adhesive. This makes it difficult to reduce the diameter of the conductive adhesive. Furthermore, this expansion of the diameter could cause contact between the conductive adhesives. To avoid this risk, the conductive adhesives must be spaced apart sufficiently. This requires a large space to place the conductive adhesive, resulting in an increase in the size of the vibration device 1. In contrast, the metal bumps 81 and 82 hardly expand in diameter like the conductive adhesive. Therefore, the diameter of the metal bumps 81 and 82 can be made sufficiently small, and the distance between them can also be made shorter. As a result, the metal bumps 81 and 82 can be placed in a small space, allowing the vibration device 1 to be miniaturized. Furthermore, since gas generation is reduced compared to conductive adhesives, it is possible to suppress changes and deterioration in the vibration characteristics of the vibration element 4 due to gas-caused contamination of the atmosphere in the housing section S, pressure changes, etc. Therefore, the vibration device 1 has excellent reliability.

[0034] While using the metal bumps 81, 82 to bond the vibration element 4 and the base 2 has the advantages of enabling the vibration device 1 to be miniaturized and suppressing gas generation, it also has the following disadvantages: The metal bumps 81, 82 are made of a metal material and have a high Young's modulus. Therefore, for example, the metal bumps 81, 82 may be plastically deformed due to thermal stress applied during the manufacturing process of the vibration device 1, particularly thermal stress caused by the difference in linear expansion coefficients between the base 2 and the vibration element 4, or due to impacts received after manufacturing. This plastic deformation may apply unintended stress to the vibration element 4, which may deteriorate the frequency characteristics of the vibration element 4 or cause unwanted vibrations or frequency hysteresis.

[0035] Therefore, in the resonator device 1, in order to suppress such plastic deformation of the metal bumps 81, 82, the metal bumps 81, 82 are disposed on the first low elastic modulus layers 51, 52. In other words, the first low elastic modulus layers 51, 52, which are softer than the metal bumps 81, 82, are interposed between the metal bumps 81, 82 and the base 2. This allows the first low elastic modulus layers 51, 52 to absorb and mitigate the thermal stress and impact described above, thereby suppressing plastic deformation of the metal bumps 81, 82. Therefore, deterioration of the frequency characteristics of the resonator element 4 and the occurrence of unwanted vibrations and frequency hysteresis can be effectively suppressed.

[0036] The above describes the resonator device 1. As described above, the resonator device 1 includes a base 2 having an upper surface 2a as a first surface and a lower surface 2b as a second surface, which are opposite surfaces; a resonator element 4 located on the upper surface 2a side of the base 2 and including a resonator substrate 41 and an electrode 42 disposed on the surface of the resonator substrate 41 facing the base 2; wiring 28, 29 as conductive layers disposed on the upper surface 2a; metal bumps 81, 82 disposed between the base 2 and the resonator element 4 and joining and electrically connecting the base 2 and the resonator element 4; and first low-elasticity layers 51, 52 interposed between the base 2 and the wiring 28, 29, overlapping the metal bumps 81, 82 in a plan view of the base 2 and having a lower elasticity than the metal bumps 81, 82. With this configuration, the first low-elasticity layers 51, 52 absorb and relieve stress, thereby effectively suppressing plastic deformation of the metal bumps 81, 82. This effectively prevents deterioration of the frequency characteristics of the vibration element 4 and the occurrence of unwanted vibrations and frequency hysteresis, resulting in a vibration device 1 with excellent reliability.

[0037] Furthermore, as described above, the first low elastic modulus layers 51, 52 are covered with the wirings 28, 29. This allows gas generated from the first low elastic modulus layers 51, 52 to be confined within the wirings 28, 29, and prevents the gas from being released into the accommodation section S. This prevents changes and deterioration in the vibration characteristics of the vibration element 4 due to gas-induced contamination of the atmosphere in the accommodation section S, pressure changes, etc. As a result, the vibration device 1 has excellent reliability.

[0038] As described above, the first low elastic modulus layers 51 and 52 are formed to contain a resin material, which makes the first low elastic modulus layers 51 and 52 sufficiently soft with respect to the metal bumps 81 and 82.

[0039] As described above, the resonator device 1 has an oscillator circuit 6A disposed on the lower surface 2b and electrically connected to the resonator elements 4. This allows for effective use of the base 2. It also allows for a shorter wiring length between the oscillator circuit 6A and the resonator elements 4, making it less susceptible to noise.

[0040] Second Embodiment Fig. 6 is a cross-sectional view showing a vibration device according to a second embodiment. Fig. 7 is a cross-sectional view showing a modified example. Fig. 6 corresponds to Fig. 3 of the first embodiment.

[0041] This embodiment is similar to the first embodiment described above, except that it has second low elastic modulus layers 53 and 54 instead of the first low elastic modulus layers 51 and 52. In the following description, differences between this embodiment and the previous embodiment will be mainly described, and similar points will not be described again. In addition, in FIG. 6, the same reference numerals are used to designate the same components as those in the previous embodiment.

[0042] 6, the resonator device 1 of this embodiment does not include the first low elastic modulus layers 51 and 52. Instead, the resonator element 4 includes second low elastic modulus layers 53 and 54 disposed on the lower surface of the resonator substrate 41. A terminal 423 is disposed on the lower surface of the second low elastic modulus layer 53, and a terminal 424 is disposed on the lower surface of the second low elastic modulus layer 54. In other words, the second low elastic modulus layer 53 is interposed between the resonator substrate 41 and the terminal 423, and the second low elastic modulus layer 54 is interposed between the resonator substrate 41 and the terminal 424. The second low elastic modulus layers 53 and 54 can have the same configuration as the first low elastic modulus layers 51 and 52, and therefore a description thereof will be omitted.

[0043] The metal bump 81 overlaps the second low elastic modulus layer 53 in a plan view of the base 2. The metal bump 81 is bonded to the wiring 28 on its lower surface, and is bonded to a portion of the terminal 423 on the second low elastic modulus layer 53 on its upper surface. As a result, the metal bump 81 bonds the vibration element 4 to the base 2 and electrically connects the wiring 28 to the terminal 423. Similarly, the metal bump 82 overlaps the second low elastic modulus layer 54 in a plan view of the base 2. The metal bump 82 is bonded to the wiring 29 on its lower surface, and is bonded to a portion of the terminal 424 on the second low elastic modulus layer 54 on its upper surface. As a result, the metal bump 82 bonds the vibration element 4 to the base 2 and electrically connects the wiring 29 to the terminal 424.

[0044] Second low elastic modulus layers 53 and 54 are disposed on the lower surface of the vibration substrate 41. The elastic modulus of these second low elastic modulus layers 53 and 54 is smaller than that of the metal bumps 81 and 82. Therefore, the second low elastic modulus layers 53 and 54 are softer than the metal bumps 81 and 82. Note that the "elastic modulus" mentioned above refers to Young's modulus. The elastic modulus of the second low elastic modulus layers 53 and 54 is preferably 1 / 10 or less, more preferably 1 / 50 or less, and even more preferably 1 / 100 or less of that of the metal bumps 81 and 82.

[0045] More details will be described with reference to the graph shown in Fig. 9. As described above, the graph shown in Fig. 9 has the Young's modulus ratio on the horizontal axis and the stress ratio of the vibrating portion on the vertical axis. The low elastic modulus layer corresponds to the second low elastic modulus layers 53 and 54. The vibrating portion corresponds to the vibrating element 4.

[0046] As described above, when the metal bumps 81 and 82 were made of gold (Au) and the elastic modulus of the low elastic modulus layer was the same as that of the metal bumps 81 and 82 (horizontal axis = 1), the stress change was plotted when the stress generated in the vibrating part was set to 1 (vertical axis = 1).

[0047] When the second low elastic modulus layers 53 and 54 are disposed on the lower surface of the vibration element 4 (described as "vibrator side" in FIG. 9) as in this embodiment, the above-described preferable numerical range can be obtained.

[0048] In this way, by interposing the second low elastic modulus layers 53, 54, which are softer than the metal bumps 81, 82, between the metal bumps 81, 82 and the vibration substrate 41, similarly to the first embodiment described above, thermal stress and impact are absorbed and alleviated by the second low elastic modulus layers 53, 54, and plastic deformation of the metal bumps 81, 82 can be suppressed. Therefore, deterioration of the frequency characteristics of the vibration element 4 and the occurrence of unwanted vibrations and frequency hysteresis can be effectively suppressed.

[0049] In particular, the surface of the second low elastic modulus layer 53, i.e., the lower surface and side surfaces, is covered with the terminal 423, and the surface of the second low elastic modulus layer 54, i.e., the lower surface and side surfaces, is covered with the terminal 424. By covering the second low elastic modulus layers 53 and 54 with the terminals 423 and 424 in this manner, gas (outgas) generated from the second low elastic modulus layers 53 and 54 can be confined within the terminals 423 and 424, and the gas can be prevented from being released into the housing section S. As a result, it is possible to prevent changes or deterioration in the vibration characteristics of the vibration element 4 due to, for example, gas-caused contamination of the atmosphere in the housing section S or pressure changes. This results in a vibration device 1 with excellent reliability. However, the configuration of the second low elastic modulus layers 53 and 54 is not particularly limited, and portions thereof may be exposed from the terminals 423 and 424.

[0050] In the present embodiment, the second low elastic modulus layers 53, 54 are disposed on the lower surface of the vibration substrate 41, but the present invention is not limited to this, and another layer may be interposed between the second low elastic modulus layers 53, 54 and the vibration substrate 41. For example, as shown in Fig. 7, the terminals 423, 424 may have a two-layer structure of lower layers 423a, 424a and upper layers 423b, 424b, in which the lower layers 423a, 424a are disposed on the lower surfaces, the second low elastic modulus layers 53, 54 are disposed on the lower layers 423a, 424a, and the upper layers 423b, 424b are disposed from above to cover the second low elastic modulus layers 53, 54.

[0051] The above describes the resonator device 1. As described above, the resonator device 1 includes a base 2 having an upper surface 2a as a first surface and a lower surface 2b as a second surface, which are opposite surfaces; a resonator element 4 located on the upper surface 2a side of the base 2 and including a resonator substrate 41 and an electrode 42 disposed on the surface of the resonator substrate 41 facing the base 2; wiring 28, 29 as a conductive layer disposed on the upper surface 2a; metal bumps 81, 82 disposed between the base 2 and the resonator element 4 and joining and electrically connecting the base 2 and the resonator element 4; and second low-elasticity layers 53, 54 interposed between the resonator substrate 41 and the electrode 42, overlapping the metal bumps 81, 82 in a plan view of the base 2 and having a lower elasticity than the metal bumps 81, 82. With this configuration, the second low-elasticity layers 53, 54 absorb and relieve stress, thereby effectively suppressing plastic deformation of the metal bumps 81, 82. This effectively prevents deterioration of the frequency characteristics of the vibration element 4 and the occurrence of unwanted vibrations and frequency hysteresis, resulting in a vibration device 1 with excellent reliability.

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

[0053] <Third embodiment> Fig. 8 is a cross-sectional view showing a resonation device according to a third embodiment, which corresponds to Fig. 3 of the first embodiment.

[0054] This embodiment is similar to the first embodiment described above, except that it includes second low elastic modulus layers 53 and 54 in addition to first low elastic modulus layers 51 and 52. In other words, this embodiment is a combination of the first and second embodiments described above. In the following description, differences between this embodiment and the previous embodiments will be mainly described, and similar points will not be described again. In addition, in FIG. 8, the same reference numerals are used to designate the same components as those in the previous embodiments.

[0055] 8 , in the vibration device 1 of this embodiment, the vibration element 4 has second low elastic modulus layers 53 and 54 arranged on the lower surface of the vibration substrate 41. The second low elastic modulus layers 53 and 54 can have the same configuration as the first low elastic modulus layers 51 and 52, and therefore a description thereof will be omitted. A terminal 423 is arranged on the lower surface of the second low elastic modulus layer 53, and a terminal 424 is arranged on the lower surface of the second low elastic modulus layer 54. In other words, the second low elastic modulus layer 53 is interposed between the vibration substrate 41 and the terminal 423, and the second low elastic modulus layer 54 is interposed between the vibration substrate 41 and the terminal 424.

[0056] As described above, in the resonator device 1 of this embodiment, the first low elastic modulus layers 51, 52, which are softer than the metal bumps 81, 82, are interposed between the metal bumps 81, 82 and the base 2, and the second low elastic modulus layers 53, 54, which are softer than the metal bumps 81, 82, are interposed between the metal bumps 81, 82 and the resonator substrate 41. This allows thermal stress and impact to be absorbed and mitigated by the first low elastic modulus layers 51, 52 and the second low elastic modulus layers 53, 54, and plastic deformation of the metal bumps 81, 82 can be more effectively suppressed. Therefore, deterioration of the frequency characteristics of the resonator element 4 and the occurrence of unwanted vibrations and frequency hysteresis can be effectively suppressed.

[0057] The above has described the vibration device 1. As described above, the vibration device 1 includes the base 2 having an upper surface 2a as a first surface and a lower surface 2b as a second surface, which are opposite surfaces, the vibration element 4 located on the upper surface 2a side of the base 2 and including a vibration substrate 41 and an electrode 42 arranged on the surface of the vibration substrate 41 facing the base 2, wirings 28 and 29 as conductive layers arranged on the upper surface 2a, metal bumps 81 and 82 arranged between the base 2 and the vibration element 4 and joining and electrically connecting the base 2 and the vibration element 4, first low-elasticity layers 51 and 52 interposed between the base 2 and the wirings 28 and 29, overlapping with the metal bumps 81 and 82 in a plan view of the base 2 and having a lower elasticity than the metal bumps 81 and 82, and second low-elasticity layers 53 and 54 interposed between the vibration substrate 41 and the electrode 42, overlapping with the metal bumps 81 and 82 in a plan view of the base 2 and having a lower elasticity than the metal bumps 81 and 82. With this configuration, the first low elastic modulus layers 51, 52 and the second low elastic modulus layers 53, 54 absorb and relieve stress, thereby effectively suppressing plastic deformation of the metal bumps 81, 82. This effectively suppresses deterioration of the frequency characteristics of the vibrating element 4 and the occurrence of unwanted vibrations and frequency hysteresis. As a result, the vibrating device 1 has excellent reliability.

[0058] The third embodiment as described above can also achieve the same effects as the first embodiment.

[0059] While the vibration device 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. Furthermore, any other components may be added to the present invention. Furthermore, each embodiment may be combined as appropriate. [Explanation of symbols]

[0060] 1...Vibration device, 10...Package, 2...Base, 2a...Upper surface, 2b...Lower surface, 20...Insulating film, 21...Through hole, 210...Through electrode, 22...Through hole, 220...Through electrode, 28...Wiring, 281...Lower layer, 282...Upper layer, 29...Wiring, 291...Lower layer, 292...Upper layer, 3...Lid, 31...Recess, 4...Vibration element, 41...Vibration substrate, 42...Electrode, 421...Excitation electrode, 422...Excitation electrode, 423...Terminal, 423a...Lower layer, 42 3b...upper layer, 424...terminal, 424a...lower layer, 424b...upper layer, 425...wiring, 426...wiring, 51...first low elastic modulus layer, 52...first low elastic modulus layer, 53...second low elastic modulus layer, 54...second low elastic modulus layer, 6...integrated circuit, 6A...oscillating circuit, 60...laminated body, 62...wiring layer, 63...insulating layer, 64...passivation film, 65...terminal layer, 651...mounting terminal, 7...joining member, 81...metal bump, 82...metal bump, S...accommodating portion.

Claims

1. A base having a first surface and a second surface, which are opposite surfaces, and an insulating film formed on the first surface. Su and a vibration substrate and the base of the vibration substrate, the vibration substrate being located on the first surface side of the base; a vibration element having an electrode disposed on a side surface thereof; a conductive layer disposed on the first surface; The vibration element is disposed between the base and the vibration element and is bonded to the base and the vibration element. a metal bump that electrically connects the conductive layer and the electrode together; The metal insulating film is interposed between the insulating film and the conductive layer of the base, and is formed in a plan view of the base. a first lower layer that overlaps the bump and is made of a resin material having a modulus of elasticity smaller than that of the metal bump; an elastic modulus layer; The first low elastic modulus layer is entirely surrounded by the conductive layer and the base. A vibration device characterized by:

2. a through electrode is formed in the base, the through electrode penetrating from the first surface to the second surface; 2. The method of claim 1, wherein the through electrode does not overlap the first low elastic modulus layer in a plan view of the base. The vibration device according to claim 1.

3. 2. The method according to claim 1, wherein the elastic modulus of the first low elastic modulus layer is 1 / 10 or less of the elastic modulus of the metal bump.

2. The vibration device according to claim 1.

4. an oscillation circuit disposed on the second surface and electrically connected to the vibration element; Item 4. The vibration device according to any one of items 1 to 3.

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