vibrating device
By introducing a soft stress-relieving layer into the vibration device, the plastic deformation caused by the difference in linear expansion coefficients is alleviated, the problem of vibration characteristic degradation caused by metal bumps is solved, and higher vibration stability and frequency accuracy are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SEIKO EPSON CORP
- Filing Date
- 2022-04-14
- Publication Date
- 2026-07-24
AI Technical Summary
In existing vibration devices, the metal bumps have a high elastic modulus and are hard, making them prone to plastic deformation due to thermal stress. This causes the quartz vibration element to produce unwanted vibrations and frequency lag, resulting in deterioration of vibration characteristics.
A soft stress-relieving layer with a lower elastic modulus than the conductive layer and conductive components is placed between the base and the conductive layer. The stress-relieving layer alleviates plastic deformation caused by the difference in linear expansion coefficients and suppresses unwanted vibrations and frequency hysteresis.
It effectively suppresses the plastic deformation of the conductive layer and conductive components caused by thermal stress, improves the vibration characteristics and frequency stability of the vibration element, and avoids cracking and wire breakage of the metal bumps.
Smart Images
Figure CN115225059B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to vibration devices. Background Technology
[0002] Patent document 1 discloses a quartz oscillator, which is a vibrating device in which a quartz vibrating element is fixed on a package by metal bumps.
[0003] Patent Document 1: Japanese Patent Application Publication No. 2016-127469
[0004] However, in the vibrating device described in Patent Document 1, the metal bump has a high elastic modulus (Young's modulus) and is relatively hard. Therefore, it is prone to plastic deformation due to thermal stress caused by the difference in the coefficients of linear expansion between the quartz vibrating element and the package. The problem is that when the metal bump undergoes plastic deformation, unwanted vibrations and frequency hysteresis are generated in the quartz vibrating element, resulting in deterioration of the vibration characteristics. Summary of the Invention
[0005] The vibrating element comprises: a base having a first surface and a second surface in a positive-negative relationship; a vibrating element located on the first surface side relative to the base, having a vibrating substrate and an electrode disposed on the base side surface of the vibrating substrate; a conductive layer disposed on the first surface, having a joint portion that engages with the electrode; and a stress-relieving layer disposed between the base and the conductive layer, at least a portion of which overlaps with the joint portion when the base is viewed from above, the stress-relieving layer having an exposed portion that protrudes from the conductive layer. Attached Figure Description
[0006] Figure 1 This is a top view showing the outline structure of the vibration device according to the first embodiment.
[0007] Figure 2 yes Figure 1 Sectional view along line AA in the diagram.
[0008] Figure 3 This is a top view showing the general structure of the vibrating device.
[0009] Figure 4 This is a top view showing the outline structure of the vibration device according to the second embodiment.
[0010] Figure 5 This is a top view showing the outline structure of the vibration device according to the third embodiment.
[0011] Figure 6 This is a top view showing the outline structure of the vibration device according to the fourth embodiment.
[0012] Figure 7 yes Figure 6 BB line section view.
[0013] Figure 8 This is a top view showing the outline structure of the vibration device according to the fifth embodiment.
[0014] Figure 9 yes Figure 8 The CC line section view.
[0015] Figure 10 This is a top view showing the outline structure of the vibration device according to the fifth embodiment.
[0016] Label Explanation
[0017] 1. Vibrating device, 1a, 1b, 1c, 1d; 10. Package; 11. Base; 11a. First side; 11b. Second side; 12. Cover; 13. Connecting component; 14. External terminal; 15. Insulating film; 16. Conductive layer; 17. Connecting part; 18. Wiring part; 19. Connection part; 20. Through hole; 21. Through electrode; 22. Wiring; 24. Stress relief layer; 25. Exposed part; 27. Recess; 28. Conductive component; 29. Internal space; 30. Vibrating element; 31. Vibrating substrate; 32. Excitation electrode; 33. Lead electrode; 34. Electrode; 66. Integrated circuit; 67. Oscillating circuit. Detailed Implementation
[0018] 1. First Implementation Method
[0019] First, refer to Figure 1 , Figure 2 as well as Figure 3 The vibration device 1 of the first embodiment will be described.
[0020] In addition, Figure 1 In order to facilitate the explanation of the internal structure of the vibrating device 1, the diagram shows the state with the cover 12 removed. Additionally, in... Figure 3 In this diagram, to facilitate explanation of the internal structure of the vibrating device 1, the state with the cover 12 and the vibrating element 30 removed is shown. Furthermore, for ease of explanation, in the following figures, the X-axis, Y-axis, and Z-axis are shown as three mutually orthogonal axes. The direction along the X-axis is referred to as the "X-direction," the direction along the Y-axis as the "Y-direction," and the direction along the Z-axis as the "Z-direction." The side opposite to the arrow on each axis is referred to as the "positive side," and the side opposite to the arrow is referred to as the "negative side." The positive side of the Z-direction is also referred to as "up," and the negative side of the Z-direction is referred to as "down." In this embodiment, the X-direction is the first direction, and the Y-direction is the second direction.
[0021] like Figure 1 and Figure 2As shown, the vibration device 1 has: a package 10 consisting of a base 11 and a cover 12; and a vibration element 30 housed in the internal space 29 of the package 10.
[0022] The package 10 has a base 11 and a cover 12 that engages with the base 11, and a vibrating element 30 is housed in an internal space 29 formed between the base 11 and the cover 12.
[0023] The base 11 is a semiconductor substrate containing single-crystal silicon, and in this embodiment, it is a silicon substrate. In addition, the base 11 is not particularly limited, and semiconductor substrates other than silicon can be used, such as semiconductor substrates of germanium, gallium arsenide, gallium phosphide, gallium nitride, silicon carbide, etc., or substrates other than semiconductor substrates such as ceramic substrates can be used.
[0024] The base 11 is plate-shaped and has a first surface 11a on which the vibrating element 30 is disposed and a second surface 11b opposite to the first surface 11a. In addition, an insulating film 15 is formed on the surface of the base 11 except for the area where it is joined with the cover 12.
[0025] A conductive layer 16 is disposed on the first surface 11a of the base 11, having a joint portion 17 that engages with an electrode 34 disposed on the surface of the vibrating substrate 31 of the vibrating element 30 on the base 11 side via conductive components 28 such as metal bumps; and a stress-relieving layer 24, which is disposed between the base 11 and the conductive layer 16, such as... Figure 2 and Figure 3 As shown, when viewed from above, i.e., from the Z direction, the base 11 overlaps with the joint 17 at least partially. Furthermore, "distributed on the first surface 11a" means "joined on the first surface 11a." Therefore, a stress-relieving layer 24, a conductive layer 16, a conductive component 28, and an electrode 34 are sequentially stacked and joined on the first surface 11a.
[0026] The conductive layer 16 has a joint portion 17 as a region for joining with the conductive component 28, a wiring portion 18 disposed on the first surface 11a of the base 11, and a connecting portion 19 connecting the joint portion 17 and the wiring portion 18.
[0027] The stress-relieving layer 24 is formed of a resin material, such as epoxy resin, acrylic resin, polyimide resin, phenolic resin, or other heat-resistant materials. By sandwiching a soft stress-relieving layer 24 with an elastic modulus smaller than that of the conductive layer 16 or the conductive component 28 between the base 11 and the conductive layer 16, a higher stress-relieving effect can be obtained. This can suppress unwanted vibrations or frequency hysteresis of the vibrating element 30 caused by plastic deformation of the conductive layer 16 or the conductive component 28 due to the difference in the coefficients of linear expansion between the vibrating element 30 and the package 10, or the deterioration of its vibration characteristics.
[0028] Furthermore, when viewed from above in the Z direction, the stress-relieving layer 24 has an exposed portion 25 on the negative side of the X direction, which is the first direction, that protrudes from the conductive layer 16. Therefore, compared to the case where the conductive layer 16 is formed to cover the entire stress-relieving layer 24, it is possible to suppress cracking or breakage of the conductive layer 16 caused by deformation of the stress-relieving layer 24 during heat cooling applied when the electrode 34 of the vibration element 30 and the conductive layer 16 are joined via the conductive member 28.
[0029] In this embodiment, the conductive layer 16 and the electrode 34 are joined via the conductive member 28, but the conductive layer 16 and the electrode 34 can also be joined directly. In this case, the joint portion 17 of the conductive layer 16 is the area joined with the electrode 34.
[0030] An external terminal 14 is formed on the second surface 11b of the base 11, which is electrically connected to the excitation electrode 32 of the vibration element 30 via the electrode 34, the conductive layer 16, etc.
[0031] Additionally, a pair of through holes 20 extending through the base 11 in the thickness direction are formed on the base 11. Conductive material is filled into the through holes 20 to form through electrodes 21. Furthermore, as... Figure 2 and Figure 3 As shown, a conductive layer 16 electrically connected to the vibrating element 30 is disposed on the first surface 11a of the base 11. The conductive layer 16 is electrically connected to the external terminal 14 via the through electrode 21 and the wiring 22 formed on the second surface 11b of the base 11. Therefore, by applying a voltage from the external terminal 14, the vibrating element 30 can be vibrated via the excitation electrode 32, and a vibration signal can be output to the outside from the external terminal 14.
[0032] The vibration element 30 housed in the internal space 29 is located on the first surface 11a side of the base 11, and has a vibration substrate 31, an excitation electrode 32 that causes the vibration substrate 31 to vibrate, an electrode 34 that outputs vibration signals to the outside and is disposed on the surface of the vibration substrate 31 on the base 11 side, and a lead electrode 33 that electrically connects the excitation electrode 32 and the electrode 34.
[0033] The vibrating element 30 is disposed on the first surface 11a of the package 10 via the conductive component 28. In addition, the vibrating substrate 31 can be an AT-cut quartz substrate, an SC-cut quartz substrate, a BT-cut quartz substrate, etc.
[0034] Both the cover 12 and the base 11 are made of silicon substrate. Therefore, the base 11 and the cover 12 have the same coefficient of linear expansion, suppressing the generation of thermal stress caused by thermal expansion, resulting in a vibrating device 1 with excellent vibration characteristics. Furthermore, the vibrating device 1 can be formed using semiconductor processes, thus enabling high-precision manufacturing and miniaturization. However, the cover 12 is not particularly limited, and semiconductor substrates other than silicon can be used, such as those made of germanium, gallium arsenide, gallium phosphide, gallium nitride, silicon carbide, etc. Alternatively, non-semiconductor substrates such as metal substrates like Kovar alloys or glass substrates can also be used.
[0035] The cover 12 has a recessed portion 27 with a bottom, which opens on the side of the base 11 and houses the vibrating element 30 inside. Furthermore, the cover 12 is joined to the base 11 via a joining member 13 on its lower surface. Therefore, the cover 12 and the base 11 together form an internal space 29 for housing the vibrating element 30. Alternatively, the base 11 and the cover 12 can be joined without the joining member 13, but using a diffusion bonding method or similar method between the metals contained in the base 11 or the cover 12.
[0036] Furthermore, the internal space 29 is airtight, in a depressurized state, preferably closer to a vacuum. This reduces viscous resistance and improves the oscillation characteristics of the vibrating element 30. However, the environment of the internal space 29 is not particularly limited; for example, it can be an environment sealed with inert gases such as nitrogen or argon, or it can be in a state other than depressurization, such as atmospheric pressure or pressurization.
[0037] As described above, the vibration device 1 of this embodiment has a stress-relieving layer 24 with a smaller elastic modulus and a softer elastic modulus than the conductive layer 16 and the conductive component 28 disposed between the base 11 and the conductive layer 16. Therefore, a higher stress-relieving effect can be obtained, and unwanted vibration of the vibration element 30, frequency hysteresis and deterioration of vibration characteristics caused by plastic deformation of the conductive layer 16 and the conductive component 28 due to the difference in the coefficient of linear expansion between the vibration element 30 and the package 10 can be suppressed.
[0038] Furthermore, since the stress buffer layer 24 has an exposed portion 25 that protrudes from the conductive layer 16, compared to the case where the conductive layer 16 covers the entire stress buffer layer 24, it is possible to suppress the reduction in the adhesion between the conductive layer 16 and the stress buffer layer 24 caused by the deformation of the stress buffer layer 24 during the heat cooling applied when the electrodes 34 of the vibration element 30 and the conductive layer 16 are joined via the conductive member 28, resulting in peeling and wire breakage due to cracking.
[0039] 2. Second Implementation Method
[0040] Next, refer to Figure 4 The vibration device 1a of the second embodiment will be described. Furthermore, in Figure 4 In order to facilitate the explanation of the internal structure of the vibrating device 1a, the diagram shows the state with the cover 12 and the vibrating element 30 removed.
[0041] Compared to the vibration device 1 of the first embodiment, the vibration device 1a of this embodiment has a first connecting portion 191 and a second connecting portion 192 extending from the joint portion 17 of the conductive layer 16a toward the positive and negative sides of the X direction, respectively. The exposed portions 25a of the stress-relieving layer 24a are located on both sides of the joint portion 17 in the Y direction. Apart from this, it is the same as the vibration device 1 of the first embodiment. In addition, the description will focus on the differences from the first embodiment described above, and the same reference numerals will be used for the same items, and their descriptions will be omitted.
[0042] like Figure 4 As shown, the vibrating device 1a has a first connecting portion 191 extending from the joint 17 of the conductive layer 16a in the positive X direction and connected to the first wiring portion 181, and a second connecting portion 192 extending from the joint 17 of the conductive layer 16a in the negative X direction and connected to the second wiring portion 182. Furthermore, the exposed portions 25a of the stress-relieving layer 24a are located on both sides of the joint 17 in the Y direction.
[0043] By adopting this structure, the adhesion between the conductive layer 16a and the stress-relieving layer 24a can be improved, and the same effect as the vibration device 1 of the first embodiment can be obtained.
[0044] 3. Third Implementation Method
[0045] Next, refer to Figure 5 The vibration device 1b of the third embodiment will be described. Furthermore, in Figure 5 In order to facilitate the explanation of the internal structure of the vibrating device 1b, the diagram shows the state with the cover 12 and the vibrating element 30 removed.
[0046] Compared to the vibration device 1 of the first embodiment, the vibration device 1b of this embodiment has a first connecting portion 191 and a second connecting portion 192 extending from the joint portion 17 of the conductive layer 16b toward the positive and negative sides of the X direction (a first direction), respectively; and a third connecting portion 193 and a fourth connecting portion 194 extending from the joint portion 17 of the conductive layer 16b toward the positive and negative sides of the Y direction (a second direction intersecting the first direction), respectively. The exposed portions 25b of the stress-relieving layer 24b are located at the four corners of the upper surface of the stress-relieving layer 24b. Otherwise, it is the same as the vibration device 1 of the first embodiment. In addition, the description focuses on the differences from the first embodiment described above, and the same reference numerals are used for the same items, and their descriptions are omitted.
[0047] like Figure 5As shown, the vibrating device 1b has a first connecting portion 191 extending from the joint 17 of the conductive layer 16b in the positive X direction and connected to the first wiring portion 181; a second connecting portion 192 extending from the joint 17 of the conductive layer 16b in the negative X direction and connected to the second wiring portion 182; a third connecting portion 193 extending from the joint 17 of the conductive layer 16b in the positive Y direction and connected to the third wiring portion 183; and a fourth connecting portion 194 extending from the joint 17 of the conductive layer 16b in the negative Y direction and connected to the fourth wiring portion 184. Additionally, the exposed portions 25b of the stress-relieving layer 24b are located at the four corners of the upper surface of the stress-relieving layer 24b.
[0048] By adopting this structure, the adhesion between the conductive layer 16b and the stress-relieving layer 24b can be further improved, and the same effect as the vibration device 1 of the first embodiment can be obtained.
[0049] 4. Fourth Implementation Method
[0050] Next, refer to Figure 6 as well as Figure 7 The vibration device 1c of the fourth embodiment will be described. Furthermore, in Figure 6 In order to facilitate the explanation of the internal structure of the vibrating device 1c, the diagram shows the state with the cover 12 and the vibrating element 30 removed.
[0051] Compared to the vibration device 1 of the first embodiment, the vibration device 1c of this embodiment has the following features: the first stress-relieving layer 241 and the second stress-relieving layer 242 are integrated; the exposed portions 25c of the first stress-relieving layer 241 and the second stress-relieving layer 242 are disposed between the first conductive layer 161 and the second conductive layer 162; otherwise, it is the same as the vibration device 1 of the first embodiment. Furthermore, the description will focus on the differences from the first embodiment described above, using the same reference numerals for identical items, and omitting their descriptions.
[0052] like Figure 6 and Figure 7 As shown, the vibration device 1c has a first conductive layer 161 bonded to the first electrode 341 via a conductive member 28, a second conductive layer 162 bonded to the second electrode 342 via a conductive member 28, a first stress-relieving layer 241 located between the base 11 and the first conductive layer 161, and a second stress-relieving layer 242 located between the base 11 and the second conductive layer 162. The first stress-relieving layer 241 and the second stress-relieving layer 242 are integrated. Furthermore, the exposed portions 25c of the first stress-relieving layer 241 and the second stress-relieving layer 242 are located between the first conductive layer 161 and the second conductive layer 162.
[0053] By adopting this structure, it is possible to make the manufacturing of stress relief layers 241 and 242 easier, further miniaturize them, and achieve the same effect as the vibration device 1 of the first embodiment.
[0054] 5. Fifth Implementation Method
[0055] Next, as an example of the vibration device 1d in the fifth embodiment, an oscillator having an oscillation circuit 67 that oscillates the vibration element 30 will be described, referring to... Figure 8 , Figure 9 as well as Figure 10 Please provide an explanation. Additionally, in Figure 8 To better illustrate the internal structure of the vibrating device 1d, the diagram shows the state with the cover 52 removed. Additionally, in... Figure 10 In order to facilitate the explanation of the internal structure of the vibrating device 1d, the diagram shows the state with the cover 52 and the vibrating element 30 removed.
[0056] The vibration device 1d of this embodiment is the same as the vibration device 1 of the first embodiment, except that an integrated circuit 66 including an oscillation circuit 67 is formed on the second surface 51b of the base 51. Furthermore, the description will focus on the differences from the first embodiment described above, and identical items will be marked with the same reference numerals, with their descriptions omitted.
[0057] like Figure 8 as well as Figure 9 As shown, the vibrating device 1d has: a package 50, which consists of a base 51 and a cover 52 that is engaged with the base 51 via a coupling member 53; and a vibrating element 30 housed in the internal space 60 of the package 50.
[0058] The base 51 and cover 52 are semiconductor substrates containing single-crystal silicon, and in this embodiment, they are silicon substrates. In addition, the base 51 and cover 52 are not particularly limited, and semiconductor substrates other than silicon can also be used, such as semiconductor substrates of germanium, gallium arsenide, gallium phosphide, gallium nitride, silicon carbide, etc.
[0059] The base 51 is plate-shaped and has a first surface 51a on which the vibrating element 30 is disposed and a second surface 51b opposite to the first surface 51a. In addition, an insulating film 55 is formed on the surface of the base 51 except for the area where it is joined with the cover 52.
[0060] A stress-relieving layer 24 and a conductive layer 16 are stacked on the first surface 51a of the base 51 and are connected to the vibration element 30 via a conductive component 28.
[0061] An integrated circuit 66 comprising an oscillation circuit 67 electrically connected to the oscillation element 30 is disposed on the second surface 51b of the base 51. By forming the integrated circuit 66 on the base 51, the base 51 can be utilized effectively. In particular, by forming the integrated circuit 66 on the second surface 51b, compared with the case where the integrated circuit 66 is formed on the first surface 51a, there is no engagement area with the cover 52, and a wider forming space for the integrated circuit 66 can be ensured accordingly. However, the integrated circuit 66 may also be formed on the first surface 51a instead of the second surface 51b of the base 51.
[0062] Integrated circuit 66 includes an oscillation circuit 67 electrically connected to the vibrating element 30, causing the vibrating element 30 to oscillate and generate an oscillation signal such as a clock signal. In addition to the oscillation circuit 67, integrated circuit 66 may also include other circuitry. Such circuitry could include, for example, a processing circuit that processes the output signal from the oscillation circuit 67, such as a PLL circuit.
[0063] A stacked body 61, consisting of a wiring layer 62, an insulating layer 63, a passivation film 64, and a terminal layer 65, is formed on the second surface 51b. Furthermore, multiple active components (not shown) formed on the second surface 51b are electrically connected via wiring 56 included in the wiring layer 62 to form an integrated circuit 66. Additionally, the terminal layer 65 has multiple mounting terminals 54 electrically connected to an oscillation circuit 67. While the stacked body 61 in the illustrated structure includes one wiring layer 62, it is not limited to this; multiple wiring layers 62 may be stacked with an insulating layer 63 in between. That is, the wiring layer 62 and the insulating layer 63 may be stacked alternately multiple times. This, for example, increases the flexibility of routing the wiring 56 within the circuit and the placement of the multiple mounting terminals 54.
[0064] Additionally, a pair of through holes 57 are formed in the base 51, extending through the base 51 along its thickness direction. Conductive material is filled into the through holes 57 to form through electrodes 58. Furthermore, as... Figure 9 and Figure 10 As shown, a conductive layer 16 electrically connected to the vibrating element 30 is disposed on the through electrode 58 on the first surface 51a side. Therefore, the conductive layer 16 can be electrically connected to the oscillation circuit 67 via the through electrode 58, enabling the vibrating element 30 to oscillate.
[0065] The cover 52 has a recessed portion 59 with a bottom, which opens on the side of the base 51 and houses the vibrating element 30 inside. Moreover, the cover 52 is engaged with the base 51 on its lower surface via a coupling member 53. Thus, the cover 52 and the base 51 together form an internal space 60 for housing the vibrating element 30.
[0066] Furthermore, the internal space 60 is airtight, in a depressurized state, preferably closer to a vacuum. This reduces viscous resistance and improves the oscillation characteristics of the vibrating element 30. However, the environment of the internal space 60 is not particularly limited; for example, it can be an environment sealed with inert gases such as nitrogen or argon, or it can be in a state other than depressurization, such as atmospheric pressure or pressurization.
[0067] By adopting this structure, the vibration device 1d with oscillation circuit 67 can be miniaturized, and the same effect as the vibration device 1 of the first embodiment can be obtained.
Claims
1. A vibrating device, comprising: The base has a first side and a second side that are in a positive-negative relationship; A vibrating element, located on the first side relative to the base, has a vibrating substrate and electrodes disposed on the base side of the vibrating substrate; A conductive layer disposed on the first surface, having a junction portion for engaging with the electrode; and A stress-relief layer, situated between the base and the conductive layer, at least partially overlaps the joint when the base is viewed from above. The stress-relieving layer has an exposed portion that protrudes from the conductive layer. The conductive layer has the bonding portion, the wiring portion disposed on the first surface, and the connecting portion connecting the bonding portion and the wiring portion. The wiring portion includes a first wiring portion disposed in the positive direction of the first direction of the joint portion, a second wiring portion disposed in the negative direction of the first direction of the joint portion, a third wiring portion disposed in the positive direction of the second direction of the joint portion intersecting with the first direction, and a fourth wiring portion disposed in the negative direction of the second direction of the joint portion. The connecting portion has a first connecting portion extending from the joint portion toward the positive side in the first direction and connected to the first wiring portion, a second connecting portion extending from the joint portion toward the negative side in the first direction and connected to the second wiring portion, a third connecting portion extending from the joint portion toward the positive side in the second direction and connected to the third wiring portion, and a fourth connecting portion extending from the joint portion toward the negative side in the second direction and connected to the fourth wiring portion.
2. The vibration device according to claim 1, wherein, The stress-relieving layer is formed by comprising a resin material.
3. The vibration device according to claim 1 or 2, wherein, The electrode has a first electrode and a second electrode. The conductive layer has a first conductive layer bonded to the first electrode and a second conductive layer bonded to the second electrode. The stress-relieving layer has a first stress-relieving layer between the base and the first conductive layer, and a second stress-relieving layer between the base and the second conductive layer. The first stress-relieving layer and the second stress-relieving layer are integrated.
4. The vibration device according to claim 1 or 2, wherein, The vibrating device has an oscillation circuit, which is disposed on the second surface and electrically connected to the vibrating element.