Vibration element, vibration device, and method for manufacturing a vibration device

Abstract

To provide a vibration element, a vibration device, and a method for manufacturing a vibration device that can reduce thermal stress.SOLUTION: A vibration element has a piezoelectric substrate including a vibration part, first and second excitation electrodes arranged on the piezoelectric substrate across the vibration part, and first and second connection electrodes arranged on the piezoelectric substrate and electrically connected with the first and second excitation electrodes, wherein the first and second connection electrodes are connected with a mounting substrate. The first connection electrode is joined to the mounting substrate with a first joint member therebetween including a first adhesive and a first bump group including at least one first bump covered by the first adhesive. The second connection electrode is joined to the mounting substrate with a second joint member therebetween including a second adhesive and a second bump group including at least one second bump covered by the second adhesive. When the width of the vibration part along a direction in which the first and second joint members are arranged side by side is defined as L1, and the maximum clearance between the first and second bumps as L2, L1≥L2 is satisfied.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a vibration element, a vibration device, and a method for manufacturing a vibration device.

Background Art

[0002] For example, Patent Document 1 describes a vibrator in which an insulating substrate and a crystal vibration element are mechanically and electrically joined via a pair of conductive adhesives. In this vibrator, a pair of metal bumps are arranged between the pair of conductive adhesives, and a predetermined space is secured between the insulating substrate and the crystal vibration element by these metal bumps. Therefore, the conductive adhesive does not collapse, and the crystal vibration element can be stably mounted on the insulating substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the vibrator of Patent Document 1, since a pair of metal bumps are arranged between the pair of conductive adhesives, the pair of conductive adhesives are largely separated. Therefore, thermal stress due to the difference in the linear expansion coefficient between the insulating substrate and the crystal vibration element is likely to be applied to the crystal vibration element, and there is a problem that, for example, it affects vibration characteristics such as hysteresis.

Means for Solving the Problems

[0005] [[ID=4l]] The vibration element of the present invention comprises a piezoelectric substrate including a vibrating portion, a first excitation electrode and a second excitation electrode disposed on the piezoelectric substrate with the vibrating portion in between, a first connecting electrode disposed on the piezoelectric substrate and electrically connected to the first excitation electrode, and a second connecting electrode disposed on the piezoelectric substrate and electrically connected to the second excitation electrode, wherein the first connecting electrode and the second connecting electrode are each bonded to a mounting substrate. The first connecting electrode is bonded to the mounting substrate via a first bonding member comprising a first adhesive and a group of first bumps including at least one first bump covered by the first adhesive. The second connecting electrode is joined to the mounting substrate via a second bonding member comprising a second adhesive and a second bump group including at least one second bump covered by the second adhesive. When L1 is the width of the vibrating portion along the direction in which the first and second joining members are aligned, and L2 is the maximum distance between the first and second bumps, then L1 ≥ L2.

[0006] The vibration device of the present invention comprises a piezoelectric substrate including a vibrating portion, a first excitation electrode and a second excitation electrode disposed on the piezoelectric substrate with the vibrating portion in between, a first connecting electrode disposed on the piezoelectric substrate and electrically connected to the first excitation electrode, and a second connecting electrode disposed on the piezoelectric substrate and electrically connected to the second excitation electrode, and a vibration element having these elements. The mounting substrate on which the vibration element is mounted, A first joining member that joins the first connecting electrode and the mounting substrate, comprising a first adhesive and a group of first bumps including at least one first bump covered by the first adhesive, The second connecting electrode and the mounting substrate are joined together, and the second joining member comprises a second adhesive and a second bump group including at least one second bump covered by the second adhesive, When L1 is the width of the vibrating portion along the direction in which the first and second joining members are aligned, and L2 is the maximum distance between the first and second bumps, then L1 ≥ L2.

[0007] The present invention provides a method for manufacturing a vibration device comprising a bump formation step of forming a first bump group including at least one first bump and a second bump group including at least one second bump on a mounting substrate, An adhesive application step of applying a first adhesive to cover the first bump group to form a first joint member, and applying a second adhesive to cover the second bump group to form a second joint member, The method includes preparing a vibrating element having a piezoelectric substrate including a vibrating portion, a first excitation electrode and a second excitation electrode disposed on the piezoelectric substrate with the vibrating portion in between, a first connecting electrode disposed on the piezoelectric substrate and electrically connected to the first excitation electrode, and a second connecting electrode disposed on the piezoelectric substrate and electrically connected to the second excitation electrode, and a vibrating element bonding step of bonding the first connecting electrode to the mounting substrate via a first bonding member and bonding the second connecting electrode to the mounting substrate via a second bonding member, When L1 is the width of the vibrating portion along the direction in which the first and second joining members are aligned, and L2 is the maximum distance between the first and second bumps, then L1 ≥ L2. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing a vibration device according to the first embodiment. [Figure 2] Figure 1 is a plan view of the vibration device shown. [Figure 3] This is a longitudinal cross-sectional view showing the first and second joining members. [Figure 4] This is a cross-sectional view showing the first and second joining members. [Figure 5] This is a cross-sectional view showing a modified example of the first and second joining members. [Figure 6] This is a cross-sectional view showing a modified example of the first and second joining members. [Figure 7] This is a cross-sectional view showing a modified example of the first and second joining members. [Figure 8]It is a cross-sectional view showing a modified example of the first joining member and the second joining member. [Figure 9] It is a cross-sectional view showing a modified example of the first joining member and the second joining member. [Figure 10] It is a cross-sectional view showing a modified example of the first joining member and the second joining member. [Figure 11] It is a plan view showing a modified example of the vibration element. [Figure 12] It is a flowchart showing the manufacturing process of the vibration device. [Figure 13] It is a cross-sectional view for explaining the manufacturing method of the vibration device. [Figure 14] It is a cross-sectional view for explaining the manufacturing method of the vibration device. [Figure 15] It is a cross-sectional view for explaining the manufacturing method of the vibration device. [Figure 16] It is a cross-sectional view for explaining the manufacturing method of the vibration device. [Figure 17] It is a cross-sectional view for explaining the manufacturing method of the vibration device. [Figure 18] It is a cross-sectional view showing the vibration device according to the second embodiment. [Figure 19] It is a cross-sectional view showing the vibration device according to the third embodiment. [Figure 20] It is a plan view of the vibration device shown in FIG. 19.

Mode for Carrying Out the Invention

[0009] Hereinafter, preferred embodiments of the vibration element, vibration device, and manufacturing method of the vibration device of the present invention will be described in detail based on the accompanying drawings.

[0010] <First Embodiment> Figure 1 is a cross-sectional view showing a vibration device according to the first embodiment. Figure 2 is a plan view of the vibration device shown in Figure 1. Figure 3 is a longitudinal cross-sectional view showing the first and second joining members. Figure 4 is a transverse cross-sectional view showing the first and second joining members. Figures 5 to 9 are transverse cross-sectional views showing modified examples of the first and second joining members, respectively. Figure 10 is a cross-sectional view showing modified examples of the first and second joining members. Figure 11 is a plan view showing modified examples of the vibration element. Figure 12 is a flowchart showing the manufacturing process of the vibration device. Figures 13 to 17 are cross-sectional views illustrating the manufacturing method of the vibration device, respectively.

[0011] For the sake of clarity, each diagram shows mutually orthogonal X, Y, and Z axes. Furthermore, below, the direction along the X-axis will be referred to as the "X-axis direction," the direction along the Y-axis as the "Y-axis direction," and the direction along the Z-axis as the "Z-axis direction." Also, the side of each axis indicated by the arrow will be referred to as the "positive side," and the opposite side as the "negative side." Additionally, the positive side of the Z-axis direction will be referred to as "up," and the negative side of the Z-axis direction as "down."

[0012] The vibration device 100 shown in Figure 1 is an oscillator and comprises a vibration element 1, a circuit element 8 including an oscillation circuit 80 that causes the vibration element 1 to oscillate, and a package 9 that houses the vibration element 1 and the circuit element 8. The package 9 has a base 91 as a mounting substrate with a recess 911 opening on its upper surface, and a plate-shaped lid 92 that is joined to the upper surface of the base 91 via a bonding member 93 so as to close the opening of the recess 911. Inside the package 9, an airtight internal space S is formed by the recess 911, and the vibration element 1 and the circuit element 8 are housed in this internal space S, respectively.

[0013] For example, the base 91 is made of a ceramic such as alumina, and the lid 92 is made of a metallic material such as Kovar. This results in a package 9 with excellent mechanical strength. Furthermore, the difference in their coefficients of thermal expansion can be kept small, thereby suppressing the generation of thermal stress. However, the constituent materials of the base 91 and the lid 92 are not particularly limited. In addition, the internal space S is in a reduced pressure state, preferably a state closer to a vacuum. This reduces viscous resistance and improves the vibration characteristics of the vibrating element 1. However, the atmosphere of the internal space S is not particularly limited.

[0014] The recess 911 includes a first recess 911a opening on the upper surface of the base 91, a second recess 911b opening on the bottom surface of the first recess 911a and smaller than the first recess 911a, and a third recess 911c opening on the bottom surface of the second recess 911b and smaller than the second recess 911b. A circuit element 8 is placed on the bottom surface of the third recess 911c, and a vibration element 1 is placed on the bottom surface of the first recess 911a.

[0015] Furthermore, a plurality of internal terminals 951 are arranged on the bottom surface of the second recess 911b, electrically connected to the circuit element 8 via bonding wire BW1; a pair of internal terminals 952 and 953 are arranged on the bottom surface of the first recess 911a, electrically connected to the vibration element 1 via conductive first and second joining members 6 and 7; and a plurality of external terminals 954 are arranged on the lower surface of the base 91. The plurality of internal terminals 951 are electrically connected to the internal terminals 952 and 953 and the external terminals 954 via internal wiring (not shown). As a result, the vibration element 1 and the circuit element 8 are electrically connected, and the circuit element 8 is electrically connected to the external terminals 954.

[0016] As shown in Figure 2, the vibrating element 1 has a piezoelectric substrate 11 and an electrode pattern arranged on the surface of the piezoelectric substrate 11. As will be described later, the vibrating element 1 is joined to the base 91 at the end on the negative side in the X-axis direction, so in the following, the end on the negative side in the X-axis direction will also be called the base end, and the end on the positive side in the X-axis direction will also be called the tip.

[0017] The piezoelectric substrate 11 is an AT-cut quartz substrate. The piezoelectric substrate 11 is plate-shaped and has an upper and lower surface that are in a front-back relationship. Furthermore, in a plan view from the thickness direction, i.e., the Z-axis direction (hereinafter simply referred to as "plan view"), the piezoelectric substrate 11 has a roughly rectangular shape with the X-axis direction as the longitudinal direction and the Y-axis direction as the transverse direction. The piezoelectric substrate 11 also includes a vibrating section 111 that is roughly rectangular in shape in a plan view.

[0018] The electrode pattern includes a first excitation electrode 121 positioned on the upper surface as an excitation electrode, a second excitation electrode 122 positioned on the lower surface opposite the first excitation electrode 121 as an excitation electrode, a first connecting electrode 123 and a second connecting electrode 124 positioned on the lower surface, a first lead electrode 125 connecting the first excitation electrode 121 and the first connecting electrode 123, and a second lead electrode 126 connecting the second excitation electrode 122 and the second connecting electrode 124. The first and second connecting electrodes 123 and 124 are arranged side by side in the Y-axis direction at the base end of the piezoelectric substrate 11.

[0019] The first excitation electrode 121 and the second excitation electrode 122 are positioned on either side of the vibrating part 111. In other words, the vibrating part 111 is positioned so as to overlap with both the first excitation electrode 121 and the second excitation electrode 122 in a plan view. The vibrating part 111 undergoes thickness-sliding vibration due to the voltage applied between the first excitation electrode 121 and the second excitation electrode 122.

[0020] The vibration element 1 has been described above, but its configuration is not particularly limited. For example, the planar shape of the piezoelectric substrate 11 is not limited to a rectangle, but may be circular, elliptical, semicircular, or other polygonal. Furthermore, the outer edge of the piezoelectric substrate 11 may be beveled, or the upper and lower surfaces of the piezoelectric substrate 11 may be convex. In addition, a mesa or inverted mesa may be formed. Moreover, instead of an AT-cut quartz oscillator, an SC-cut quartz oscillator, a BT-cut quartz oscillator, a tuning fork-type quartz oscillator, a surface acoustic wave resonator, other piezoelectric vibration elements, MEMS resonant elements, etc., may be used as the vibration element 1.

[0021] The vibrating element 1, configured in this way, is joined to the base 91 via a first joining member 6 and a second joining member 7. The first joining member 6 and the second joining member 7 are arranged side by side in the Y-axis direction. As shown in Figure 3, the first joining member 6 is located between the internal terminal 952 and the first connecting electrode 123, electrically connecting them. On the other hand, the second joining member 7 is located between the internal terminal 953 and the second connecting electrode 124, electrically connecting them. As a result, the vibrating element 1 and the base 91 are mechanically joined by the first and second joining members 6 and 7, and the vibrating element 1 and the circuit element 8 are electrically connected.

[0022] The first joining member 6 has a first adhesive 61 and a first bump group 62 covered by the first adhesive 61. The first bump group 62 also includes a plurality of first bumps 621. Similarly, the second joining member 7 has a second adhesive 71 and a second bump group 72 covered by the second adhesive 71. The second bump group 72 also includes a plurality of second bumps 721.

[0023] The first adhesive 61 is conductive and mechanically joins the internal terminal 951 and the first connecting electrode 123, while also providing an electrical connection. Similarly, the second adhesive 71 is conductive and mechanically joins the internal terminal 952 and the second connecting electrode 124, while also providing an electrical connection. This facilitates the electrical connection between the base 91 and the vibrating element 1. The first and second adhesives 61 and 71 are not particularly limited as long as they are conductive; for example, various epoxy, acrylic, and silicone resin adhesives containing conductive fillers such as metal particles can be used. This simplifies the construction of the first adhesive 61 and the second adhesive 71.

[0024] Each first bump 621 is embedded in the first adhesive 61. Similarly, each second bump 721 is embedded in the second adhesive 71. Each of these first bumps 621 and each of the second bumps 721 is rigid and functions as a spacer to ensure a predetermined distance D between the base 91 and the vibrating element 1. Therefore, when mounting the vibrating element 1 on the base 91, excessive deformation of the first adhesive 61 and the second adhesive 71 is restricted, suppressing the expansion of the diameter of the first adhesive 61 and the second adhesive 71, and allowing for easy control of the diameter. In this way, the first adhesive 61 and the second adhesive 71 can be controlled to a small diameter and a predetermined size, allowing the first joining member 6 and the second joining member 7 to be placed closer together while preventing contact between them. Therefore, the thermal stress applied to the vibrating element 1 due to the difference in the coefficient of linear expansion between the vibrating element 1 and the base 91 can be kept to a minimum. As a result, it is possible to effectively suppress the deterioration of vibration characteristics, such as hysteresis.

[0025] In particular, by embedding each first bump 621 within the first adhesive 61, the amount of first adhesive 61 applied can be reduced. As a result, the wetting and spreading of the first adhesive 61 is suppressed, and the diameter of the first adhesive 61 can be made smaller. Furthermore, the surface tension with each first bump 621 suppresses the wetting and spreading of the first adhesive 61, and the diameter of the first adhesive 61 can be made smaller. In other words, each first bump 621 has the function of an anchor that suppresses the wetting and spreading of the first adhesive 61, in addition to the function of a spacer as described above.

[0026] The same applies to the second bumps 721. In other words, by embedding each second bump 721 within the second adhesive 71, the amount of second adhesive 71 applied can be reduced. As a result, the wetting and spreading of the second adhesive 71 is suppressed, and the diameter of the second adhesive 71 can be made smaller. In addition, the surface tension with each second bump 721 suppresses the wetting and spreading of the second adhesive 71, and the diameter of the second adhesive 71 can be made smaller. In other words, each second bump 721 has the function of an anchor that suppresses the wetting and spreading of the second adhesive 71, in addition to the function of a spacer as described above.

[0027] Here, the number of first bumps 621 in the first bump group 62 and the number of second bumps 721 in the second bump group 72 are not particularly limited, but it is preferable that there be multiple, i.e., two or more. This increases the strength of the first and second bump groups 62 and 72, and allows them to perform their function as spacers more reliably. The upper limit of the number of first and second bumps 621 and 721 is not particularly limited, but it is preferable that there be 10 or fewer, and more preferably 5 or fewer, for each. This prevents the first and second joining members 6 and 7 from becoming excessively large in diameter.

[0028] In this embodiment, as shown in Figure 4, four first bumps 621 and four second bumps 721 are arranged in a substantially square shape. This allows the number and arrangement of the first bumps 621 and second bumps 721 to be optimal, while keeping the diameters of the first and second connecting members 6 and 7 sufficiently small, and allowing them to fully perform their functions as spacers and anchors, respectively. However, the number and arrangement of the first bumps 621 and second bumps 721 are not particularly limited and can be appropriately set depending on the size of the vibrating element 1, the arrangement of the first and second connecting electrodes 123 and 124, etc. For example, as shown in Figure 5, one more bump may be added to the center of the first bumps 621 and second bumps 721, as shown in Figure 6, three may be arranged in a substantially equilateral triangle shape, as shown in Figure 7, two may be arranged in the X-axis direction, as shown in Figure 8, two may be arranged in the Y-axis direction, or only one may be arranged, as shown in Figure 9. Furthermore, the number and arrangement of the first bump 621 and the second bump 721 may differ.

[0029] Each first bump 621 is harder than the first adhesive 61, and each second bump 721 is harder than the second adhesive 71. In other words, each first bump 621 has a higher Young's modulus than the first adhesive 61, and each second bump 721 has a higher Young's modulus than the second adhesive 71. In particular, in this embodiment, each first and second bump 621, 721 is made of a metal bump. This makes each first and second bump 621, 721 sufficiently rigid, allowing them to more reliably perform their function as spacers as described above. Each first and second bump 621, 721 is made of, for example, a stud bump using wire bonding technology, a plated bump, etc. However, the constituent materials and forming methods of each first and second bump 621, 721 are not particularly limited.

[0030] Furthermore, as shown in Figure 3, each first bump 621 is composed of multiple bumps 621a stacked on top of each other. With this configuration, the height of the first bump 621 can be easily controlled by the number of bumps 621a stacked. This makes it easier to control the spacing D. Moreover, by stacking multiple bumps 621a, the surface area of ​​the first bump 621 can be increased, and irregularities can be formed on the surface of the first bump 621. This further improves the anchoring effect mentioned above.

[0031] Similarly, each second bump 721 is composed of multiple bumps 721a stacked on top of each other. With this configuration, the height of the second bump 721 can be easily controlled by the number of bumps 721a stacked. This makes it easier to control the spacing D. Furthermore, by stacking multiple bumps 721a, the surface area of ​​the second bump 721 can be increased, and irregularities can be formed on the surface of the second bump 721. This further improves the aforementioned anchoring effect.

[0032] However, the configuration of the first and second bumps 621 and 721 is not particularly limited, and for example, they may be composed of one bump 621a, 721a.

[0033] Furthermore, in this embodiment, the first bump group 62, that is, each first bump 621, is spaced apart from the first connecting electrode 123. In other words, each first bump 621 and the first connecting electrode 123 are not in contact. Similarly, the second bump group 72, that is, each second bump 721, is spaced apart from the second connecting electrode 124. In other words, each second bump 721 and the second connecting electrode 124 are not in contact. This makes it possible to suppress a decrease in the contact area between the first and second adhesives 61, 71 and the first and second connecting electrodes 123, 124, and to increase the bonding strength between them.

[0034] However, this is not limited to this. For example, as shown in Figure 10, the first bump group 62 may be in contact with the first connecting electrode 123, and the second bump group 72 may be in contact with the second connecting electrode 124. This allows the internal terminal 951 to be electrically connected to the first connecting electrode 123 via the first bump group 62, and the internal terminal 952 to be electrically connected to the second connecting electrode 124 via the second bump group 72. Therefore, it becomes possible to use insulating adhesives as the first and second adhesives 61 and 71, increasing the range of material options.

[0035] Furthermore, when L1 is the width of the vibrating section 111 along the direction in which the first joining member 6 and the second joining member 7 are aligned, i.e., along the Y-axis direction, and L2 is the maximum separation distance between the first bump 621 and the second bump 721, the relationship L1 ≥ L2 is satisfied. As a result, the separation distance L3 between the first joining member 6 and the second joining member 7 can be reduced, and the thermal stress applied to the vibrating element 1 due to the difference in the coefficient of linear expansion between the vibrating element 1 and the base 91 can be kept to a minimum. Therefore, for example, the deterioration of the vibration characteristics of the vibrating element 1, such as hysteresis, can be effectively suppressed. Note that the maximum separation distance L2 refers to the separation distance along the Y-axis direction between the first bump 621 that is furthest from the second joining member 7 in the Y-axis direction among the multiple first bumps 621, and the second bump 721 that is furthest from the first joining member 6 in the Y-axis direction among the multiple second bumps 721.

[0036] As shown in Figure 3, the separation distance includes the widths of the first bump 621 and the second bump 721 themselves. That is, the maximum separation distance L2 between the first bump 621 and the second bump 721 is the sum of the width of the first bump 621 along the Y-axis, the width of the second bump 721 along the Y-axis, and the distance between the first bump 621 and the second bump 721 along the Y-axis.

[0037] As described above, it is sufficient to satisfy the relationship L1≧L2, but it is preferable to satisfy the relationship 0.9L1≧L2, and even more preferable to satisfy the relationship 0.8L1≧L2. This allows the separation distance L3 to be further reduced, and the deterioration of the vibration characteristics of the vibration element 1 can be suppressed even more effectively.

[0038] In this embodiment, since the first and second excitation electrodes 121 and 122 have the same shape, L1 may be the width of the first excitation electrode 121 or the width of the second excitation electrode 122. On the other hand, if the first and second excitation electrodes 121 and 122 have different shapes, for example as shown in Figure 11, then L1 may be the width of the smaller of the two excitation electrodes 121 and 122, i.e., the width of the second excitation electrode 122.

[0039] Furthermore, if the first and second excitation electrodes 121 and 122 do not completely overlap and are partially offset, the width of the overlapping portion of the first and second excitation electrodes 121 and 122 should be defined as L1. In this embodiment, the first joining member 6 and the second joining member 7 are arranged so as to be within the range of the vibrating portion 111 in the Y-axis direction, but this arrangement is not necessarily required, as long as the relationship L1 ≥ L2 is satisfied. Also, the plan view shape of the first excitation electrode 121, the second excitation electrode 122, and the vibrating portion 111 is not limited to a rectangle, but may be circular, elliptical, oblong, semicircular, or other polygonal. In that case, the maximum width of the vibrating portion 111 in the Y-axis direction should be defined as L1.

[0040] Next, a method for manufacturing the vibration device 100 will be described. As shown in Figure 12, the method for manufacturing the vibration device 100 includes a bump formation step S1, an adhesive application step S2, a vibration element bonding step S3, and a lid bonding step S4.

[0041] <<Bump formation process S1>> First, as shown in Figure 13, a base 91 is prepared. Although not shown, a circuit element 8 is already mounted on this base 91. Next, as shown in Figure 14, a plurality of first bumps 621 are formed on the base 91 to obtain a first bump group 62, and a plurality of second bumps 721 are formed to obtain a second bump group 72. The first and second bumps 621 and 721 can be formed using stud bumps or plated bumps, respectively, using wire bonding technology. In this step, the first and second bump groups 62 and 72 are formed such that the maximum separation distance L2 between the first bump 621 and the second bump 721 is smaller than the width L1 of the vibrating section 111.

[0042] ≪Adhesive application process S2≫ Next, as shown in Figure 15, an uncured first adhesive 61 is applied to the first bump group 62, and an uncured second adhesive 71 is applied to the second bump group 72. This results in a first joint member 6 in which the first bump group 62 is covered with the first adhesive 61, and a second joint member 7 in which the second bump group 72 is covered with the second adhesive 71.

[0043] ≪Vibration element bonding process S3≫ Next, the vibrating element 1 is prepared. Then, as shown in Figure 16, the vibrating element 1 is placed on the first and second joining members 6 and 7 so as to be pressed against the first and second bump groups 62 and 72. As mentioned above, at this time, the first and second bump groups 62 and 72 function as spacers to secure a predetermined distance D between the base 91 and the vibrating element 1. Therefore, excessive crushing of the first and second adhesives 61 and 71 can be suppressed, and contact between the first and second adhesives 61 and 71 can be effectively suppressed. Next, the first and second adhesives 61 and 71 are cured. As a result, the first connecting electrode 123 is joined to the base 91 via the first joining member 6, and the second connecting electrode 124 is joined to the base 91 via the second joining member 7.

[0044] ≪Lid joining process S4≫ Next, prepare the lid 92. Then, as shown in Figure 17, join the lid 92 to the upper surface of the base 91 via the joining member 93. This completes the vibration device 100.

[0045] According to the manufacturing method described above, the relationship L1 ≥ L2 is satisfied, so the separation distance L3 between the first joining member 6 and the second joining member 7 can be reduced, and the thermal stress applied to the vibrating element 1 due to the difference in the coefficient of linear expansion between the vibrating element 1 and the base 91 can be kept to a minimum. Therefore, the deterioration of the vibration characteristics of the vibrating element 1, such as hysteresis, can be effectively suppressed.

[0046] The vibration device 100 and the method for manufacturing the vibration device 100 have been described above. As described above, the vibration element 1 of the vibration device 100 includes a piezoelectric substrate 11 including a vibrating part 111, first and second excitation electrodes 121 and 122 arranged on the piezoelectric substrate 11 with the vibrating part 111 in between, a first connecting electrode 123 arranged on the piezoelectric substrate 11 and electrically connected to the first excitation electrode 121, and a second connecting electrode 124 arranged on the piezoelectric substrate 11 and electrically connected to the second excitation electrode 122, with the first connecting electrode 123 and the second connecting electrode 124 each being bonded to the base 91 which is a mounting substrate. Furthermore, the first connecting electrode 123 is joined to the base 91 via a first joining member 6 which comprises a first adhesive 61 and a first bump group 62 including at least one first bump 621 covered by the first adhesive 61, and the second connecting electrode 124 is joined to the base 91 via a second joining member 7 which comprises a second adhesive 71 and a second bump group 72 including at least one second bump 721 covered by the second adhesive 71. Also, when L1 is the width of the vibrating portion 111 along the Y-axis direction in which the first joining member 6 and the second joining member 7 are aligned, and L2 is the maximum separation distance between the first bump 621 and the second bump 721, then L1 ≥ L2. This makes it possible to reduce the separation distance L3 between the first joining member 6 and the second joining member 7 while preventing contact between the first and second joining members 6 and 7. Therefore, the thermal stress applied to the vibrating element 1 due to the difference in the coefficient of linear expansion between the vibrating element 1 and the base 91 can be kept to a minimum. As a result, the deterioration of the vibration characteristics of the vibrating element 1, such as hysteresis, can be effectively suppressed.

[0047] Furthermore, as mentioned above, the first bump group 62 includes multiple first bumps 621, and the second bump group 72 includes multiple second bumps 721. This increases the strength of the first and second bump groups 62 and 72, allowing them to more reliably perform their function as spacers as described above.

[0048] Furthermore, as mentioned above, the first bump 621 and the second bump 721 are each composed of multiple bumps 621a and 721a stacked on top of each other. This makes it easy to control the height of the first and second bumps 621 and 721 by the number of bumps 621a and 721a that are stacked. As a result, the spacing D becomes easier to control. Moreover, by stacking multiple bumps 621a and 721a, the surface area of ​​the first and second bumps 621 and 721 can be increased, and irregularities can be formed on the surface of the first and second bumps 621 and 721. As a result, the aforementioned anchoring effect is further improved.

[0049] Furthermore, as mentioned above, the first adhesive 61 and the second adhesive 71 are both electrically conductive. This facilitates the electrical connection between the base 91 and the vibrating element 1.

[0050] Furthermore, as mentioned above, the first bump 621 is spaced apart from the first connecting electrode 123, and the second bump 721 is spaced apart from the second connecting electrode 124. This suppresses a reduction in the contact area between the first and second adhesives 61 and 71 and the first and second connecting electrodes 123 and 124, thereby increasing the bonding strength.

[0051] As mentioned above, the vibration device 100 includes a vibration element 1 having a piezoelectric substrate 11 including a vibrating part 111, first and second excitation electrodes 121 and 122 arranged on the piezoelectric substrate 11 with the vibrating part 111 in between, a first connecting electrode 123 arranged on the piezoelectric substrate 11 and electrically connected to the first excitation electrode 121, and a second connecting electrode 124 arranged on the piezoelectric substrate 11 and electrically connected to the second excitation electrode 122; a base 91 which is a mounting substrate on which the vibration element 1 is mounted; a first joining member 6 which joins the first connecting electrode 123 and the base 91 and includes a first adhesive 61 and a first bump group 62 including at least one first bump 621 covered by the first adhesive 61; and a second joining member 7 which joins the second connecting electrode 124 and the base 91 and includes a second adhesive 71 and a second bump group 72 including at least one second bump 721 covered by the second adhesive 71. Furthermore, when L1 is the width of the vibrating section 111 along the Y-axis direction in which the first joining member 6 and the second joining member 7 are aligned, and L2 is the maximum separation distance between the first bump 621 and the second bump 721, then L1 ≥ L2. This makes it possible to reduce the separation distance L3 between the first joining member 6 and the second joining member 7 while preventing contact between the first and second joining members 6 and 7. As a result, the thermal stress applied to the vibrating element 1 due to the difference in the coefficient of linear expansion between the vibrating element 1 and the base 91 can be kept to a minimum. Consequently, the deterioration of the vibration characteristics of the vibrating element 1, such as hysteresis, can be effectively suppressed.

[0052] Furthermore, as mentioned above, the manufacturing method of the vibration device 100 includes a bump forming step S1 in which a first bump group 62 including at least one first bump 621 and a second bump group 72 including at least one second bump 721 are formed on a base 91 which is a mounting substrate; an adhesive coating step S2 in which a first adhesive 61 is applied to cover the first bump group 62 to form a first joining member 6 and a second adhesive 71 is applied to cover the second bump group 72 to form a second joining member 7; a piezoelectric substrate 11 including a vibrating part 111; and a vibrating part 1 The manufacturing method includes preparing a vibrating element 1 having first and second excitation electrodes 121 and 122 arranged on the piezoelectric substrate 11 with 11 in between, a first connecting electrode 123 arranged on the piezoelectric substrate 11 and electrically connected to the first excitation electrode 121, and a second connecting electrode 124 arranged on the piezoelectric substrate 11 and electrically connected to the second excitation electrode 122, and a vibrating element joining step S3 in which the first connecting electrode 123 is joined to the base 91 via a first joining member 6 and the second connecting electrode 124 is joined to the base 91 via a second joining member 7. Furthermore, when the width of the vibrating portion 111 along the Y-axis direction, which is the direction in which the first joining member 6 and the second joining member 7 are aligned, is L1, and the maximum separation distance between the first bump 621 and the second bump 721 is L2, then L1 ≥ L2. With such a manufacturing method, it is possible to reduce the separation distance L3 between the first joining member 6 and the second joining member 7 while preventing contact between the first and second joining members 6 and 7. Therefore, the thermal stress applied to the vibrating element 1 due to the difference in the coefficient of linear expansion between the vibrating element 1 and the base 91 can be kept to a minimum. As a result, the deterioration of the vibration characteristics of the vibrating element 1, such as hysteresis, can be effectively suppressed.

[0053] <Second Embodiment> Figure 18 is a cross-sectional view showing a vibration device according to the second embodiment.

[0054] The vibration device 100 of this embodiment is the same as the vibration device 100 of the first embodiment described above, except that the configuration of the first and second joining members 6 and 7 is different. Therefore, in the following description, this embodiment will be described mainly in terms of the differences from the first embodiment described above, and similar matters will not be described. Also, in the figures of this embodiment, the same reference numerals are used for components that are the same as those in the previously described embodiment.

[0055] As shown in Figure 18, in the vibration device 100 of this embodiment, of the four first bumps 621 included in the first joint member 6, the height of the two first bumps 621 located on the base end side (negative side in the X-axis direction) is lower than the height of the two first bumps 621 located on the tip end side (positive side in the X-axis direction). Similarly, of the four second bumps 721 included in the second joint member 7, the height of the two second bumps 721 located on the base end side is lower than the height of the two second bumps 721 located on the tip end side. With this configuration, the vibration element 1 can be placed on the base 91 in an inclined position with its tip end facing upward. This suppresses sinking of the tip of the vibration element 1 and suppresses contact between the vibration element 1 and the base 91.

[0056] The height and placement of the first and second bumps 621 and 721 can be appropriately set depending on the orientation in which the vibration element 1 is mounted.

[0057] As described above, in the vibration device 100 of this embodiment, the first bump group 62 includes first bumps 621 of different heights, and the second bump group 72 includes second bumps 721 of different heights. This allows the vibration element 1 to be mounted in an inclined position relative to the base 91.

[0058] This second embodiment can also achieve the same effects as the first embodiment described above.

[0059] <Third Embodiment> Figure 19 is a cross-sectional view showing a vibration device according to the third embodiment. Figure 20 is a plan view of the vibration device shown in Figure 19.

[0060] The vibration device 100 of this embodiment is the same as the vibration device 100 of the first embodiment described above, except that it is an oven-controlled crystal oscillator (OCXO). Therefore, in the following description, this embodiment will be described mainly for the differences from the first embodiment described above, and similar matters will not be described. Also, in the figures of this embodiment, the same reference numerals are used for components that are the same as in the previously described embodiment.

[0061] As shown in Figure 19, in the vibration device 100 of this embodiment, the recess 911 of the base 91 has a first recess 911a opening on the upper surface of the base 91, a second recess 911b opening on the bottom surface of the first recess 911a and smaller than the first recess 911a, a third recess 911c opening on the bottom surface of the second recess 911b and smaller than the second recess 911b, and a fourth recess 911d opening on the bottom surface of the third recess 911c and smaller than the third recess 911c. A circuit element 8 is arranged on the bottom surface of the fourth recess 911d, and a vibration element 1 is arranged on the bottom surface of the second recess 911b via a temperature control element 2 acting as a heater. In this embodiment, the temperature control element 2 corresponds to the mounting substrate.

[0062] Furthermore, as shown in Figure 20, the bottom surface of the third recess 911c is provided with a plurality of internal terminals 951 that are electrically connected to the circuit element 8 via bonding wire BW1, and the bottom surface of the first recess 911a is provided with a pair of internal terminals 952 and 953 that are electrically connected to the vibration element 1 via bonding wire BW2 and relay electrodes 28 and 29 on the temperature control element 2, and a plurality of internal terminals 955 that are electrically connected to the temperature control element 2 via bonding wire BW3.

[0063] The temperature control element 2 includes a temperature sensor 21 and a heating circuit 22. The temperature sensor 21 functions as a temperature detection unit that detects the ambient temperature, particularly the temperature of the vibration element 1, and the heating circuit 22 functions as a heating unit that heats the vibration element 1. The heating circuit 22 is controlled based on the detection result of the temperature sensor 21 to maintain the vibration element 1 at a predetermined temperature. By housing the temperature control element 2 in the same internal space S as the vibration element 1 in this way, the difference between the detection result of the temperature sensor 21 and the actual temperature of the vibration element 1 is reduced, resulting in a vibration device 100 with excellent frequency-temperature characteristics.

[0064] Furthermore, the first connecting electrode 123 of the vibrating element 1 is mechanically and electrically connected to the relay electrode 28 via the first joining member 6, and the second connecting electrode 124 is mechanically and electrically connected to the relay electrode 29 via the second joining member 7.

[0065] This third embodiment can also achieve the same effects as the first embodiment described above. In this embodiment, the vibration device 100 is applied to an oven-controlled crystal oscillator (OCXO), but it is not limited to this and may be applied to any oscillator, such as a temperature-compensated crystal oscillator (TCXO) or a voltage-controlled crystal oscillator (VCXO).

[0066] Although the vibration element, vibration device, and method for manufacturing the vibration device of the present invention have been described above based on the illustrated embodiments, the present invention is not limited thereto, and the configuration of each part can be replaced with any configuration having a similar function. Furthermore, other arbitrary components may be added to the present invention. In addition, the embodiments described above may be combined as appropriate. [Explanation of Symbols]

[0067] 1...Vibration element, 100...Vibration device, 11...Piezoelectric substrate, 111...Vibration part, 121...First excitation electrode, 122...Second excitation electrode, 123...First connecting electrode, 124...Second connecting electrode, 125...First extraction electrode, 126...Second extraction electrode, 2...Temperature control element, 21...Temperature sensor, 22...Heating circuit, 28...Intermediate electrode, 29...Intermediate electrode, 6...First joining member, 61...First adhesive, 62...First bump group, 621...First bump, 621a...Bump, 7...Second joining member, 71...Second adhesive, 72...Second bump group, 721...Second bump, 721a...Bump, 8...Circuit element, 80...Electric Vibration circuit, 9...package, 91...base, 911...recess, 911a...first recess, 911b...second recess, 911c...third recess, 911d...fourth recess, 92...lid, 93...joining member, 951...internal terminal, 952...internal terminal, 953...internal terminal, 954...external terminal, 955...internal terminal, BW1...bonding wire, BW2...bonding wire, BW3...bonding wire, D...width, L1...width, L2...maximum separation distance, L3...separation distance, S...internal space, S1...bump formation process, S2...adhesive application process, S3...vibration element bonding process, S4...lid bonding process

Claims

1. A vibrating element comprising a piezoelectric substrate including a vibrating portion, a first excitation electrode and a second excitation electrode disposed on the piezoelectric substrate with the vibrating portion in between, a first connecting electrode disposed on the piezoelectric substrate and electrically connected to the first excitation electrode, and a second connecting electrode disposed on the piezoelectric substrate and electrically connected to the second excitation electrode, wherein the first connecting electrode and the second connecting electrode are each bonded to a mounting substrate, The first connecting electrode is joined to the mounting substrate via a first bonding member comprising a first adhesive and a first bump group consisting of four first bumps covered by the first adhesive. The second connecting electrode is joined to the mounting substrate via a second bonding member comprising a second adhesive and a second bump group consisting of four second bumps covered by the second adhesive. The direction in which the first joining member and the second joining member are aligned is defined as the first direction. The four first bumps are arranged in two rows of two along the first direction and are arranged in a substantially square shape. The four second bumps are arranged in two rows of two along the first direction and are arranged in a substantially square shape. Let L1 be the width of the vibrating portion along the first direction. A vibrating element characterized in that, when L2 is the maximum distance between the end of the first bump furthest from the second joining member and the end of the second bump furthest from the first joining member and the end of the second bump furthest from the first joining member and the end of the second bump furthest from the first joining member and the end of the second bump furthest from the first joining member and the end of the second bump furthest from the first joining member, L1 ≥ L2.

2. The aforementioned first bump group includes the aforementioned first bumps of different heights, The vibration element according to claim 1, wherein the second bump group includes second bumps of different heights.

3. The vibration element according to claim 1 or claim 2, wherein the first bump and the second bump are each composed of multiple bumps stacked on top of each other.

4. The vibration element according to any one of claims 1 to 3, wherein the first adhesive and the second adhesive are each electrically conductive.

5. The first bump is spaced apart from the first connecting electrode. The vibrating element according to any one of claims 1 to 4, wherein the second bump is spaced apart from the second connecting electrode.

6. A vibrating element comprising: a piezoelectric substrate including a vibrating portion; a first excitation electrode and a second excitation electrode disposed on the piezoelectric substrate with the vibrating portion in between; a first connecting electrode disposed on the piezoelectric substrate and electrically connected to the first excitation electrode; and a second connecting electrode disposed on the piezoelectric substrate and electrically connected to the second excitation electrode; The mounting substrate on which the vibration element is mounted, A first joining member that joins the first connecting electrode and the mounting substrate, and comprises a first adhesive and a first bump group consisting of four first bumps covered by the first adhesive, The second connecting electrode and the mounting substrate are joined together, and the second joining member comprises a second adhesive and a second bump group consisting of four second bumps covered by the second adhesive, The direction in which the first joining member and the second joining member are aligned is defined as the first direction. The four first bumps are arranged in two rows of two along the first direction and are arranged in a substantially square shape. The four second bumps are arranged in two rows of two along the first direction and are arranged in a substantially square shape. Let L1 be the width of the vibrating portion along the first direction. A vibration device characterized in that, when L2 is the maximum distance between the end of the first bump furthest from the second joining member and the end of the second bump furthest from the first joining member and the end of the second bump furthest from the first joining member and the end of the second bump furthest from the first joining member and the end of the second bump furthest from the first joining member and the end of the second bump furthest from the first joining member, L1 ≥ L2.

7. A bump formation step in which a first bump group including four first bumps and a second bump group including four second bumps are formed on the mounting substrate, An adhesive application step of applying a first adhesive to cover the first bump group to form a first joint member, and applying a second adhesive to cover the second bump group to form a second joint member, The method includes preparing a vibrating element having a piezoelectric substrate including a vibrating portion, a first excitation electrode and a second excitation electrode disposed on the piezoelectric substrate with the vibrating portion in between, a first connecting electrode disposed on the piezoelectric substrate and electrically connected to the first excitation electrode, and a second connecting electrode disposed on the piezoelectric substrate and electrically connected to the second excitation electrode, and a vibrating element bonding step of bonding the first connecting electrode to the mounting substrate via a first bonding member and bonding the second connecting electrode to the mounting substrate via a second bonding member, The direction in which the first joining member and the second joining member are aligned is defined as the first direction. The four first bumps are arranged in two rows of two along the first direction and are arranged in a substantially square shape. The four second bumps are arranged in two rows of two along the first direction and are arranged in a substantially square shape. Let L1 be the width of the vibrating portion along the first direction. A method for manufacturing a vibration device, characterized in that when L2 is the maximum distance between the end of the first bump furthest from the second joining member and the end of the second bump furthest from the first joining member and the end of the second bump furthest from the first joining member and the end of the second bump furthest from the first joining member and the end of the second bump furthest from the first joining member and the end of the second bump furthest from the first joining member, L1 ≥ L2.

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