Vibration device

Abstract

The reliability of the vibration device and the electric connection is excellent. A resonator device (1) is provided with: a semiconductor substrate (10) that includes a first surface (11) and a second surface (12) that is in positive and negative relationship with the first surface (11), and in which a first through-hole (13) that penetrates from the first surface (11) to the second surface (12) is formed; a first conductive layer (15) that is disposed on the second surface (12) side of the semiconductor substrate (10) and that overlaps the first through-hole (13) in plan view; an organic resin (23) that is formed on a side surface of the first through-hole (13) and on a portion of the first surface (11) of the semiconductor substrate (10) that is located around an opening of the first through-hole (13) on the first surface (11) side; a first wiring (17) that is formed on the surface of the first conductive layer (15) exposed from the first through-hole (13), the surface of the organic resin (23), and a first region (19) of the first surface (11) of the semiconductor substrate (10) that does not overlap the organic resin (23); and a vibration element (30) bonded to a portion of the first wiring (17) disposed in the first region (19) by a first bonding member (21).

Description

Technical Field

[0001] The present invention relates to a vibrating device. Background Art

[0002] For example, Patent Document 1 discloses a vibration device in which a first terminal is arranged on a first surface of a silicon substrate having a through hole, a second terminal is arranged on a second surface, a resin layer is arranged between a wiring that passes through the through hole and electrically connects the first terminal and the second terminal and the inner wall of the through hole, and a vibration element is bonded to the first terminal. By arranging the resin layer between the wiring and the inner wall of the through hole, it is possible to reduce the parasitic capacitance formed between the silicon substrate and the wiring.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-195116

[0004] However, in the vibration device described in Patent Document 1, a resin layer is also arranged between the first terminal and the first surface. Therefore, when the vibration element is heated and pressurized to be joined on the first terminal, the electrode film of the first terminal is deformed due to the softness of the resin layer, and cracks may occur in the electrode film, resulting in breakage. Summary of the invention

[0005] The vibration device comprises: a semiconductor substrate, which includes a first surface and a second surface that is in a positive and negative relationship with the first surface, and has a first through hole that passes from the first surface to the second surface; a first conductive layer, which is arranged on the second surface side of the semiconductor substrate and overlaps with the first through hole when viewed from above; an organic resin, which is formed on the side of the first through hole and a portion of the first surface of the semiconductor substrate around the opening of the first through hole on the first surface side; a first wiring, which is formed on the surface of the first conductive layer exposed from the first through hole, the surface of the organic resin, and a first area of ​​the first surface of the semiconductor substrate that does not overlap with the organic resin; and a vibration element, which is joined to the portion of the first wiring arranged in the first area through a first joining component. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a perspective view showing a schematic structure of the vibration device according to the first embodiment.

[0007] Figure 2 It is a plan view showing a schematic structure of the vibration device according to the first embodiment.

[0008] Figure 3 yes Figure 2 A1-A1 line section view.

[0009] Figure 4 yes Figure 2A2-A2 line section view.

[0010] Figure 5 It is a plan view showing a schematic structure of a vibration device according to a second embodiment.

[0011] Figure 6 yes Figure 5 A3-A3 line section view.

[0012] Figure 7 yes Figure 5 A4-A4 line section view.

[0013] Description of symbols

[0014] 1. 1a: vibration device; 2: package; 10: semiconductor substrate; 11: first surface; 12: second surface; 13: first through hole; 14: second through hole; 15: first conductive layer; 16: second conductive layer; 17: first wiring; 18: second wiring; 19: first region; 20: second region; 21: first bonding member; 22: second bonding member; 23: organic resin; 25: cover; 26: recess; 27: storage space; 28: external terminal ; 29: Joining part; 30: Vibration element; 31: Vibration substrate; 32: Excitation electrode; 33: Lead electrode; 34: Pad electrode; 35: Side electrode; 36: Main surface; 50: Silicon substrate; 51: Silicon oxide layer; 52: Oscillation circuit; 61: First part; 62: Second part; 63: Corner; 65: Imaginary line; 131, 141: Side; 171: First wiring layer; 172: Second wiring layer; 301: One end; 302: The other end. DETAILED DESCRIPTION

[0015] 1. First Implementation

[0016] As the vibration device 1 of the first embodiment, an oscillator including a vibration element 30 and an oscillation circuit 52 is taken as an example. Figure 1 to Figure 4 Provide explanation.

[0017] exist Figure 2 and Figure 4 In order to facilitate the explanation of the internal structure of the vibration device 1, the state in which the cover 25 is removed is illustrated. In the subsequent stereoscopic views, top views and cross-sectional views, for the convenience of explanation, the X-axis, Y-axis and Z-axis are illustrated as three axes that are orthogonal to each other. The direction along the X-axis is called the "X direction", the direction along the Y-axis is called the "Y direction", and the direction along the Z-axis is called the "Z direction". The arrow side of each axis is also called the "positive side", and the side opposite to the arrow is called the "negative side". The positive side of the Z direction is also called "up", and the negative side of the Z direction is called "down". In this embodiment, the first direction is the X direction, and the second direction is the Y direction.

[0018] like Figure 1 , Figure 2 and Figure 3 As shown, the vibration device 1 includes a semiconductor substrate 10, a cover 25, and a vibration element 30. The semiconductor substrate 10 and the cover 25 constitute a package 2 that houses the vibration element 30.

[0019] The semiconductor substrate 10 is composed of a silicon substrate 50 and a silicon oxide layer 51, and the silicon oxide layer 51 is arranged on the upper surface of the silicon substrate 50. When viewed from above in the Z direction, the semiconductor substrate 10 is a rectangular flat plate. The semiconductor substrate 10 includes a first surface 11 that becomes the upper surface of the silicon oxide layer 51 and a second surface 12 that is in a positive and negative relationship with the first surface 11, and is formed with a first through hole 13 and a second through hole 14 that penetrate from the first surface 11 to the second surface 12. When viewed from above, the first through hole 13 and the second through hole 14 are arranged in the Y direction on the negative side of the X direction of the semiconductor substrate 10, the first through hole 13 is arranged on the positive side of the Y direction, and the second through hole 14 is arranged on the negative side of the Y direction.

[0020] An oscillation circuit 52 is formed on the second surface 12 side of the semiconductor substrate 10, and a first conductive layer 15 is provided at a position overlapping with the first through hole 13 when viewed from above, and a second conductive layer 16 is provided at a position overlapping with the second through hole 14 when viewed from above. The first conductive layer 15 and the second conductive layer 16 are electrically connected to the oscillation circuit 52. The oscillation circuit 52 oscillates the vibration element 30 to generate the frequency of a reference signal such as a clock signal. A plurality of external terminals 28 for supplying voltage to the oscillation circuit 52 and outputting an oscillation frequency are provided on the lower surface of the oscillation circuit 52.

[0021] On the first surface 11 of the semiconductor substrate 10, there are provided a first wiring 17 electrically connecting the first bonding component 21 of the bonding vibration element 30 to the first conductive layer 15, and a second wiring 18 electrically connecting the second bonding component 22 of the bonding vibration element 30 to the second conductive layer 16. The first wiring 17 is arranged at a position overlapping with the first through hole 13 when viewed from above, and extends in the positive Y direction, and the second wiring 18 is arranged at a position overlapping with the second through hole 14 when viewed from above, and extends in the negative Y direction. The first bonding component 21 is arranged in a first region 19 extending in the positive Y direction of the first wiring 17 and not arranged with an organic resin 23 described later, and the second bonding component 22 is arranged in a second region 20 extending in the negative Y direction of the second wiring 18 and not arranged with an organic resin 23 described later. In addition, as the constituent material of the first bonding component 21 and the second bonding component 22, metal bumps such as Au (gold) and solder are preferred. The first wiring 17 is led out from the region where the organic resin 23 is arranged to the outside thereof. The first region 19 is a region where the organic resin 23 is not arranged and is a region where the first wiring 17 is provided. That is, the first region 19 is a region that does not overlap with the organic resin 23 in the region where the first wiring 17 is arranged. The second wiring 18 is led outward from the region where the organic resin 23 is arranged. The second region 20 is a region where the organic resin 23 is not arranged and is a region where the second wiring 18 is provided. That is, the second region 20 is a region that does not overlap with the organic resin 23 in the region where the second wiring 18 is arranged.

[0022] When the direction from one end 301 toward the other end 302 of the vibration element 30 is taken as the first direction and the direction perpendicular to the first direction and along the main surface 36 of the vibration element is taken as the second direction, the first bonding member 21 is located on one side of the Y direction as the second direction, that is, the positive side of the Y direction, when viewed from above, and the second bonding member 22 is located on the other side of the Y direction as the second direction, that is, the negative side of the Y direction, when viewed from above. In the Y direction, the first through hole 13 and the second through hole 14 are arranged between the first bonding member 21 and the second bonding member 22, and in the X direction as the first direction, the range where the first through hole 13 and the second through hole 14 are arranged overlaps with the range where the first bonding member 21 is arranged and the range where the second bonding member 22 is arranged.

[0023] When viewed from above in the Z direction, the cover 25 is rectangular in shape and has a recess 26 that opens toward the semiconductor substrate 10. The cover 25 is bonded to the first surface 11 of the semiconductor substrate 10 via a bonding member 29. The vibration element 30 is accommodated in the storage space 27, which is a space surrounded by the cover 25 and the semiconductor substrate 10. In addition, the storage space 27 is airtight and is in a reduced pressure state, preferably a state closer to a vacuum. As a result, the viscous resistance is reduced and the vibration characteristics of the vibration element 30 are improved. However, the atmosphere of the storage space 27 is not particularly limited.

[0024] Silicon is preferably used as a constituent material of the cover 25. By making the semiconductor substrate 10 and the cover 25 of silicon, the linear expansion coefficients are equal, and the generation of thermal stress caused by thermal expansion is suppressed, resulting in a vibration device 1 having excellent vibration characteristics. In addition, since the vibration device 1 can be formed by a semiconductor process, the vibration device 1 can be manufactured with high precision and miniaturization can be achieved.

[0025] The semiconductor substrate 10 and the cover body 25 are bonded by a bonding member 29 such as glass frit, but are not limited thereto. A metal eutectic bonding method may be used to bond the metal film formed on the first surface 11 of the semiconductor substrate 10 and the surface of the cover body 25 in contact with the semiconductor substrate 10. Alternatively, an activation bonding method may be used to bond the surface of the first surface 11 of the semiconductor substrate 10 and the surface of the metal film such as Au formed on the surface of the cover body 25 in contact with the semiconductor substrate 10 by activating them through plasma irradiation. Alternatively, direct bonding without inclusions may be used between two bonding surfaces of the same material.

[0026] The vibration element 30 has one end 301 and the other end 302. The one end 301 is bonded by the first bonding member 21 and the second bonding member 22. The vibration element 30 has a vibration substrate 31 made of a quartz substrate, and an excitation electrode 32 and a pad electrode 34 provided on a principal surface 36 of the vibration substrate 31.

[0027] An excitation electrode 32 is provided on the upper surface of the vibration substrate 31, and an excitation electrode 32 and two pad electrodes 34 at positions overlapping with the first bonding member 21 and the second bonding member 22 when viewed from above are provided on the lower surface of the vibration substrate 31. The excitation electrode 32 provided on the upper surface of the vibration substrate 31 is electrically connected to the pad electrode 34 provided on the negative side in the Y direction of the lower surface of the vibration substrate 31 via the lead electrode 33 and the side electrode 35 on the one end 301 side. The excitation electrode 32 provided on the lower surface of the vibration substrate 31 is electrically connected to the pad electrode 34 on the positive side in the Y direction via the lead electrode 33. The two pad electrodes 34 are bonded to the semiconductor substrate 10 via the first bonding member 21 and the second bonding member 22, respectively. The area of ​​the excitation electrode 32 on the upper surface is the same as that of the excitation electrode 32 on the lower surface, and they are arranged to overlap when viewed from above.

[0028] In the present embodiment, the vibration substrate 31 is made of quartz, but is not limited thereto, and may be made of piezoelectric single crystals such as lithium niobate, lithium tantalate, lithium tetraborate, lanthanum gallium silicate, potassium niobate, gallium phosphate, or other piezoelectric single crystals. The vibration element 30 is not limited to a piezoelectrically driven vibration element, but may be an electrostatically driven vibration element using electrostatic force.

[0029] Next, refer to Figure 4 The structures of the first through hole 13 and the first wiring 17 will be described.

[0030] like Figure 4 As shown, the semiconductor substrate 10 has the first through hole 13 formed therein so as to overlap with the first conductive layer 15 in a plan view.

[0031] An organic resin 23 serving as an insulating layer is formed on the side surface 131 of the first through hole 13 and on the first surface 11 of the semiconductor substrate 10 around the opening of the first through hole 13 on the first surface 11 side. By using the organic resin 23 as the insulating layer, the organic resin 23 can be formed in such a manner that the opening width on the second surface 12 side of the semiconductor substrate 10 is narrower than the opening width on the first surface 11 side of the semiconductor substrate 10.

[0032] Thus, the organic resin 23 has a tapered shape with a larger opening width on the first surface 11 side, so that coverage of the first wiring 17 arranged on the organic resin 23 can be improved, and the resistance of the first wiring 17 can be reduced.

[0033] On the organic resin 23, in other words, on the surface of the organic resin 23, the first wiring 17 is formed over the first conductive layer 15. The first wiring 17 is formed on the surface of the first conductive layer 15 exposed from the first through hole 13, the surface of the organic resin 23, and the first region 19 of the first surface 11 of the semiconductor substrate 10 that does not overlap with the organic resin 23. A portion of the first region 19 overlaps with the first bonding member 21. Therefore, the vibration element 30 is bonded to the portion of the first wiring 17 arranged in the first region 19 through the first bonding member 21. That is, the vibration element 30 can be bonded to the first bonding member 21 at a position of the first surface 11 of the semiconductor substrate 10 that is separated from the portion around the opening of the first through hole 13 in which the organic resin 23 is formed and does not overlap with the organic resin 23.

[0034] The first wiring 17 includes a second wiring layer 172 disposed on a first wiring layer 171. The first wiring layer 171 is a laminated film composed of, for example, TiW (titanium tungsten) / Cu (copper). Alternatively, the first wiring layer 171 may contain, for example, at least one of Cu (copper) and Al (aluminum) instead of Cu (copper).

[0035] The second wiring layer 172 is formed to cover the entire first wiring layer 171. The second wiring layer 172 is, for example, a stacked film composed of TiW (titanium tungsten) / Au (gold).

[0036] In this way, the first wiring layer 171 uses a Cu (copper) material, and the second wiring layer 172 uses an Au (gold) material, so that the resistance can be reduced and the degradation of the vibration characteristics of the vibration element 30 can be suppressed. In addition, since the first wiring 17 is formed into a two-layer structure of the first wiring layer 171 and the second wiring layer 172, the resistance of the first wiring 17 that electrically connects the vibration element 30 and the first conductive layer 15 can be reduced.

[0037] Furthermore, since the first wiring layer 171 made of Cu (copper) or the like is formed under the second wiring layer 172, the cost can be suppressed compared to the case where the conductive layer is formed only of Au (gold) having a low resistance.

[0038] The structures of the second through hole 14 and the second wiring 18 are also the same as those of the first through hole 13 and the first wiring 17 , and the second through hole 14 is formed so as to overlap with the second conductive layer 16 in a plan view.

[0039] The organic resin 23 is formed on the side surface 141 of the second through hole 14 and a portion of the first surface 11 of the semiconductor substrate 10 around the opening of the second through hole 14 on the first surface 11 side.

[0040] The second wiring 18 is formed on the surface of the second conductive layer 16 exposed from the second through hole 14 , the surface of the organic resin 23 , and the second region 20 of the first surface 11 of the semiconductor substrate 10 that does not overlap with the organic resin 23 .

[0041] The vibration element 30 is bonded to the portion of the second wiring 18 arranged in the second region 20 through the second bonding member 22. That is, the vibration element 30 can be bonded to the portion of the first surface 11 of the semiconductor substrate 10 that is separated from the portion around the opening of the second through hole 14 in which the organic resin 23 is formed and does not overlap with the organic resin 23 through the second bonding member 22.

[0042] As described above, in the vibration device 1 of the present embodiment, the first bonding member 21 and the second bonding member 22 are arranged in the first area 19 and the second area 20 of the first wiring 17 and the second wiring 18 that do not overlap with the organic resin 23, and the first wiring 17 and the second wiring 18 electrically connect the first conductive layer 15 and the second conductive layer 16 that are electrically connected to the oscillation circuit 52 and the first bonding member 21 and the second bonding member 22 that are bonded to the vibration element 30. Therefore, when the vibration element 30 is heated and pressurized on the first wiring 17 and the second wiring 18 and bonded via the first bonding member 21 and the second bonding member 22, disconnection due to deformation, cracks, etc. of the first wiring 17 and the second wiring 18 can be reduced. Therefore, the vibration device 1 with excellent reliability of electrical connection can be obtained.

[0043] 2. Second Implementation

[0044] Next, refer to Figure 5 , Figure 6 and Figure 7 A resonator device 1 a according to the second embodiment will be described.

[0045] exist Figure 5 and Figure 7 In order to facilitate the description of the internal structure of the vibration device 1, a state in which the cover 25 is removed is shown.

[0046] The vibration device 1a of this embodiment is the same as the vibration device 1 of the first embodiment, except for the configuration positions of the first through hole 13 and the second through hole 14 and the structures of the first wiring 17 and the second wiring 18. In addition, the description will focus on the differences from the above-mentioned first embodiment, and the same items are marked with the same numbers and their descriptions are omitted.

[0047] like Figure 5 and Figure 6 As shown, the vibration device 1a includes a semiconductor substrate 10a, a cover 25, and a vibration element 30. The semiconductor substrate 10a and the cover 25 constitute a package 2a that houses the vibration element 30.

[0048] On the first surface 11 of the semiconductor substrate 10a, there are provided a first wiring 17a that electrically connects the first bonding component 21 of the bonding vibration element 30 and the first conductive layer 15, and a second wiring 18a that electrically connects the second bonding component 22 of the bonding vibration element 30 and the second conductive layer 16. The first wiring 17a is arranged at a position overlapping with the first through hole 13a when viewed from above, and extends in the positive Y direction and then in the negative X direction, and the second wiring 18a is arranged at a position overlapping with the second through hole 14a when viewed from above, and extends in the negative Y direction and then in the negative X direction.

[0049] The first bonding member 21 is arranged in the first region 19 a extending in the negative X direction of the first wiring 17 a and not provided with the organic resin 23 . The second bonding member 22 is arranged in the second region 20 a extending in the negative X direction of the second wiring 18 and not provided with the organic resin 23 .

[0050] The first through hole 13a and the second through hole 14a are arranged in the Y direction between the first bonding member 21 and the second bonding member 22. In the X direction, the range where the first through hole 13 and the second through hole 14 are arranged is arranged closer to the other end 302 of the vibration element 30 than the range where the first bonding member 21 and the second bonding member 22 are arranged, that is, the positive side in the X direction.

[0051] like Figure 7As shown, when observed in cross section, the length between the first surface 11 of the semiconductor substrate 10a and the end portion of the surface of the first bonding component 21 on the side of the vibration element 30, that is, the first portion 61 on the side of the other end 302 is set to H1, the distance between the first portion 61 and the second portion 62 on the imaginary line 65 that passes through the first portion 61 and is tangent to the second portion 62 of the first wiring 17a on the organic resin 23 formed on the first surface 11 around the first through hole 13a and intersects the first surface 11 is set to L1, the length between the first surface 11 of the semiconductor substrate 10 and the second portion 62 is set to H2, and the distance between the first portion 61 and the corner portion 63 of the other end 302 of the vibration element 30 on the side of the semiconductor substrate 10 is set to L2, the vibration device 1a of this embodiment satisfies (H1-H2)×L2 / H1>L1. By satisfying (H1-H2)×L2 / H1>L1, it is possible to reduce the contact between the excitation electrode 32 provided on the lower surface of the vibration element 30 and the first wiring 17a or the second wiring 18a when the vibration element 30 is bonded to the semiconductor substrate 10a or when an impact is applied to the vibration device 1a.

[0052] By adopting such a structure, it is possible to reduce the contact between the excitation electrode 32 and the first wiring 17 a or the second wiring 18 a when the vibration element 30 is bonded or when an impact is applied, and it is possible to obtain the same effects as those of the first embodiment.

Claims

1. A vibration device, comprising: A semiconductor substrate comprising a first surface and a second surface that is opposite to the first surface, and having a first through hole extending from the first surface to the second surface; a first conductive layer disposed on the second surface side of the semiconductor substrate and overlapping the first through hole when viewed from above; an organic resin formed on a side surface of the first through hole and a portion of the first surface of the semiconductor substrate around an opening of the first through hole on the first surface side; a first wiring formed on a surface of the first conductive layer exposed from the first through hole, a surface of the organic resin, and a first region of the first surface of the semiconductor substrate that does not overlap with the organic resin; as well as A vibration element is bonded to a portion of the first wiring arranged in the first region via a first bonding member.

2. The vibration device according to claim 1, wherein: The vibration element has one end and the other end, the one end side is joined by the first joining member, When the first through hole is arranged closer to the other end side than the first bonding member, When observing the section, The length between the first surface of the semiconductor substrate and the first portion of the surface of the first bonding member on the vibration element side, which is the end portion on the other end side, is denoted as H1. The distance between the first portion and the second portion on an imaginary line that passes through the first portion and is tangent to the second portion of the first wiring formed on the organic resin on the first surface around the first through hole and intersects the first surface is defined as L1, The length between the first surface and the second portion of the semiconductor substrate is set to H2, When the distance between the first portion and the corner of the other end of the vibration element on the semiconductor substrate side is defined as L2, (H1-H2)×L2 / H1>L1.

3. The vibration device according to claim 1, wherein The vibration device further includes a second conductive layer and a second wiring. A second through hole is formed in the semiconductor substrate and passes through from the first surface to the second surface. The second conductive layer is disposed on the second surface side of the semiconductor substrate and overlaps with the second through hole when viewed from above. The organic resin is formed on the side surface of the second through hole and a portion of the first surface of the semiconductor substrate around the opening of the second through hole on the first surface side. The second wiring is formed on a surface of the second conductive layer exposed from the second through hole, a surface of the organic resin, and a second region of the first surface of the semiconductor substrate that does not overlap with the organic resin. The vibration element is bonded to a portion of the second wiring arranged in the second region via a second bonding member.

4. The vibration device according to claim 3, wherein: When a direction from one end toward the other end of the vibration element is defined as a first direction, and a direction perpendicular to the first direction and along a main surface of the vibration element is defined as a second direction, When viewed from above, the first joining component is located on one side of the second direction. When viewed from above, the second joining member is located on the other side of the second direction. In the second direction, the first through hole and the second through hole are arranged between the first bonding member and the second bonding member.

5. The vibration device according to claim 3, wherein: When a direction from one end toward the other end of the vibration element is defined as a first direction, and a direction perpendicular to the first direction and along a main surface of the vibration element is defined as a second direction, When viewed from above, the first joining component is located on one side of the second direction. When viewed from above, the second joining member is located on the other side of the second direction. In the first direction, a range where the first through hole and the second through hole are arranged overlaps a range where the first bonding member is arranged. In the first direction, a range where the first through-hole and the second through-hole are arranged overlaps a range where the second bonding member is arranged.

6. The vibration device according to claim 1 or 2, wherein: The semiconductor substrate includes an oscillation circuit formed on the second surface side and electrically connected to the first conductive layer.

7. The vibration device according to any one of claims 3 to 5, wherein: The semiconductor substrate includes an oscillation circuit formed on the second surface side and electrically connected to the first conductive layer and the second conductive layer.

8. The vibration device according to any one of claims 1 to 5, wherein: The vibration device further includes a cover body bonded to the first surface side of the semiconductor substrate. The vibration element is accommodated in a space surrounded by the cover and the semiconductor substrate.

9. The vibration device according to claim 6, wherein: The vibration device further includes a cover body bonded to the first surface side of the semiconductor substrate. The vibration element is accommodated in a space surrounded by the cover and the semiconductor substrate.

10. The vibration device according to claim 7, wherein: The vibration device further includes a cover body bonded to the first surface side of the semiconductor substrate. The vibration element is accommodated in a space surrounded by the cover and the semiconductor substrate.

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