Vibration device

Abstract

To provide a vibration device excellent in electrical connection reliability.SOLUTION: A vibration device 1 has: a semiconductor substrate 10 which includes a first surface 11 and a second surface 12 that is in a front-and-rear relationship with the first surface 11, and which is provided with a first through-hole 13 penetrating the semiconductor substrate from the first surface 11 to the second surface 12; a first conductive layer 15, disposed on the second surface 12 side of the semiconductor substrate 10, which overlaps the first through-hole 13 in plan view; organic resin 23 which is formed on a lateral surface of the first through-hole 13 and on the first surface 11 of the semiconductor substrate 10 around an opening, of the first through-hole 13, on the first surface 11 side; first wiring 17 which is formed on a surface of the first conductive layer 15 exposed from the first through-hole 13, a surface of the organic resin 23, and in a first region 19 that is a portion of the first surface 11 of the semiconductor substrate 10 not overlapping the organic resin 23; and a vibration element 30 which is bonded by a first bonding member 21 to a portion of the first wiring 17 disposed in the first region 19.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] For example, Patent Document 1 discloses a vibration device in which a first terminal is disposed on a first surface of a silicon substrate having a through hole, a second terminal is disposed on a second surface, a wiring that electrically connects the first terminal and the second terminal through the through hole, and a resin layer is disposed between the inner wall of the through hole and the first terminal, and a vibration element is bonded on the first terminal. By disposing a resin layer between the wiring and the inner wall of the through hole, the parasitic capacitance formed between the silicon substrate and the wiring can be reduced.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the vibration device described in Patent Document 1, since a resin layer is also disposed between the first terminal and the first surface, when the vibration element is heated and pressed onto the first terminal for bonding, the resin layer is soft, so the electrode film of the first terminal may be deformed, and there is a risk that cracks will occur in the electrode film and disconnection will occur.

Means for Solving the Problems

[0005] The vibration device includes a semiconductor substrate having a first surface and a second surface that is in a front-back relationship with the first surface, and a first through hole formed to penetrate 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 in plan view, an organic resin formed on the side surface of the first through hole and the first surface of the semiconductor substrate around the opening on the first surface side of the first through hole, a first wiring formed on the surface of the first conductive layer exposed from the first through hole, the surface of the organic resin, and a first region of the first surface of the semiconductor substrate that does not overlap the organic resin, and a vibration element joined to a portion of the first wiring disposed in the first region by a first joining member.

Brief Description of the Drawings

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0007] 1. First Embodiment As the vibration device 1 according to the first embodiment, an oscillator including a vibration element 30 and an oscillation circuit 52 is taken as an example, and will be described with reference to FIGS. 1 to 4. In FIGS. 2 and 4, for the convenience of explaining the internal structure of the vibration device 1, the state in which the lid body 25 is removed is illustrated. In the subsequent perspective views, plan views, and cross-sectional views, for the convenience of explanation, the X-axis, Y-axis, and Z-axis are illustrated as three axes orthogonal to each other. The direction along the X-axis is referred to as the "X direction", the direction along the Y-axis is referred to as the "Y direction", and the direction along the Z-axis is referred to as the "Z direction". The arrow side of each axis is also referred to as the "plus side", and the side opposite to the arrow is also referred to as the "minus side". The plus side in the Z direction is also referred to as "up", and the minus side in the Z direction is also referred to as "down". In the present embodiment, the first direction is the X direction, and the second direction is the Y direction.

[0008] As shown in FIGS. 1, 2, and 3, the vibration device 1 includes a semiconductor substrate 10, a lid body 25, and a vibration element 30. The semiconductor substrate 10 and the lid body 25 constitute a package 2 that houses the vibration element 30.

[0009] The semiconductor substrate 10 is composed of a silicon substrate 50 and a silicon oxide layer 51, and the silicon oxide layer 51 is disposed on the upper surface of the silicon substrate 50. The semiconductor substrate 10 is a rectangular flat plate in a plan view from the Z direction. The semiconductor substrate 10 includes a first surface 11 that is the upper surface of the silicon oxide layer 51 and a second surface 12 that is in a front-back relationship with the first surface 11, and a first through hole 13 and a second through hole 14 that penetrate from the first surface 11 to the second surface 12 are formed. The first through hole 13 and the second through hole 14 are arranged side by side in the Y direction on the minus side in the X direction of the semiconductor substrate 10 in a plan view. The first through hole 13 is disposed on the plus side in the Y direction, and the second through hole 14 is disposed on the minus side in the Y direction.

[0010] An oscillation circuit 52 is formed on the second surface 12 side of the semiconductor substrate 10. A first conductive layer 15 is provided at a position overlapping the first through hole 13 in a plan view, and a second conductive layer 16 is provided at a position overlapping the second through hole 14 in a plan view. 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 the oscillation frequency are provided on the lower surface of the oscillation circuit 52.

[0011] On the first surface 11 of the semiconductor substrate 10, there are provided a first wiring 17 that electrically connects a first bonding member 21 for bonding the vibration element 30 and the first conductive layer 15, and a second wiring 18 that electrically connects a second bonding member 22 for bonding the vibration element 30 and the second conductive layer 16. The first wiring 17 is disposed at a position overlapping the first through hole 13 in plan view and extends in the plus Y direction, and the second wiring 18 is disposed at a position overlapping the second through hole 14 in plan view and extends in the minus Y direction. The first bonding member 21 extends in the plus Y direction of the first wiring 17 and is disposed in a first region 19 where an organic resin 23 to be described later is not disposed, and the second bonding member 22 extends in the minus Y direction of the second wiring 18 and is disposed in a second region 20 where the organic resin 23 to be described later is not disposed. Incidentally, as the constituent materials of the first bonding member 21 and the second bonding member 22, metal bumps such as Au (gold) and solder are preferable. The first wiring 17 is drawn out from the region where the organic resin 23 is disposed to the outside thereof. The first region 19 is a region where the organic resin 23 is not disposed and where the first wiring 17 is provided. That is, the first region 19 is a region of the disposed region of the first wiring 17 that does not overlap the organic resin 23. The second wiring 18 is drawn out from the region where the organic resin 23 is disposed to the outside thereof. The second region 20 is a region where the organic resin 23 is not disposed and where the second wiring 18 is provided. That is, the second region 20 is a region of the disposed region of the second wiring 18 that does not overlap the organic resin 23.

[0012] When the direction from one end 301 to the other end 302 of the vibration element 30 is defined as the first direction, and the direction orthogonal to the first direction and along the main surface 36 of the vibration element is defined as the second direction, in a plan view, the first joining member 21 is located on the plus side in the Y direction, which is one side in the second direction (Y direction), and in a plan view, the second joining member 22 is located on the minus side in the Y direction, which is the other side in the second direction (Y direction). In the Y direction, the first through hole 13 and the second through hole 14 are disposed between the first joining member 21 and the second joining member 22, and in the X direction, which is the first direction, the range where the first through hole 13 and the second through hole 14 are disposed overlaps with the range where the first joining member 21 is disposed and the range where the second joining member 22 is disposed.

[0013] The lid 25 is rectangular in a plan view from the Z direction, and a recess 26 that opens to the semiconductor substrate 10 side is formed. The lid 25 is joined to the first surface 11 of the semiconductor substrate 10 via a joining member 29. The vibration element 30 is accommodated in an accommodation space 27, which is a space surrounded by the lid 25 and the semiconductor substrate 10. Note that the accommodation space 27 is airtight and is in a reduced pressure state, preferably a state closer to a vacuum state. As a result, the viscous resistance is reduced, and the vibration characteristics of the vibration element 30 are improved. However, the atmosphere in the accommodation space 27 is not particularly limited.

[0014] Silicon is preferably used as the constituent material of the lid 25. By using silicon for both the semiconductor substrate 10 and the lid 25, the linear expansion coefficients become equal, the generation of thermal stress due to thermal expansion is suppressed, and the vibration device 1 having excellent vibration characteristics is obtained. 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 miniaturized.

[0015] The joining of the semiconductor substrate 10 and the lid 25 is a method of joining through a joining member 29 such as glass frit, but is not limited thereto. A metal eutectic joining method in which metal films formed on the first surface 11 of the semiconductor substrate 10 and the surface of the lid 25 in contact with the semiconductor substrate 10 are joined may also be used. Alternatively, an activation joining method in which the surface of the first surface 11 of the semiconductor substrate 10 and the surface of a metal film such as Au formed on the surface of the lid 25 in contact with the semiconductor substrate 10 are activated by plasma irradiation and joined may also be used. Or, a direct joining method that does not require an inclusion between two joining surfaces of the same material may also be used.

[0016] The vibrating element 30 has one end 301 and the other end 302, and one end 301 side is joined by the first joining member 21 and the second joining member 22. The vibrating element 30 includes a vibrating substrate 31 made of a crystal substrate, and an exciting electrode 32 and a pad electrode 34 provided on the main surface 36 of the vibrating substrate 31.

[0017] The exciting electrode 32 is provided on the upper surface of the vibrating substrate 31, and on the lower surface of the vibrating substrate 31, the exciting electrode 32 and two pad electrodes 34 are provided at positions overlapping the first joining member 21 and the second joining member 22 in plan view. The exciting electrode 32 provided on the upper surface of the vibrating substrate 31 is electrically connected to the pad electrode 34 on the minus side in the Y direction provided on the lower surface of the vibrating substrate 31 via the lead electrode 33 and the side electrode 35 on the one end 301 side. The exciting electrode 32 provided on the lower surface of the vibrating substrate 31 is electrically connected to the pad electrode 34 on the plus side in the Y direction via the lead electrode 33. The two pad electrodes 34 are each joined to the semiconductor substrate 10 via the first joining member 21 and the second joining member 22. The area of the exciting electrode 32 on the upper surface and the area of the exciting electrode 32 on the lower surface are the same and are arranged to overlap in plan view.

[0018] In this embodiment, the vibrating substrate 31 is made of quartz, but it is not limited thereto. For example, it may be made of a piezoelectric single crystal such as lithium niobate, lithium tantalate, lithium tetraborate, langasite, potassium niobate, or gallium phosphate, or may be made of a piezoelectric single crystal other than these. The vibrating element 30 is not limited to a piezoelectric drive type vibrating element, and may be an electrostatic drive type vibrating element using electrostatic force.

[0019] Next, the configurations of the first through hole 13 and the first wiring 17 will be described with reference to FIG. 4.

[0020] As shown in FIG. 4, the semiconductor substrate 10 has a first through hole 13 formed therein so as to overlap the first conductive layer 15 in a plan view.

[0021] 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 on the first surface 11 side of the first through hole 13. By using the organic resin 23 as the insulating layer, the organic resin 23 can be formed so that the opening width on the second surface 12 side is narrower than the opening width on the first surface 11 side of the semiconductor substrate 10.

[0022] Thus, since the organic resin 23 has a tapered shape with a wider opening width on the first surface 11 side, it is possible to improve the coverage of the first wiring 17 disposed on the organic resin 23, and the electrical resistance of the first wiring 17 can be reduced.

[0023] On the organic resin 23, in other words, on the surface of the organic resin 23, the first wiring 17 is formed across 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, on the surface of the organic resin 23, and on the first region 19 of the first surface 11 of the semiconductor substrate 10 that does not overlap with the organic resin 23. A part of the first region 19 overlaps with the first bonding member 21. Therefore, the vibration element 30 is joined by the first bonding member 21 to the portion of the first wiring 17 disposed in the first region 19. That is, the vibration element 30 can be joined by the first bonding member 21 at a position away from the first surface 11 of the semiconductor substrate 10 around the opening of the first through hole 13 in which the organic resin 23 is formed and not overlapping with the organic resin 23.

[0024] The first wiring 17 has a second wiring layer 172 disposed on the first wiring layer 171. The first wiring layer 171 is, for example, a laminated film made of TiW (titanium - tungsten) / Cu (copper). Incidentally, instead of Cu (copper), for example, at least one of Cu (copper) and Al (aluminum) may be included.

[0025] The second wiring layer 172 is formed so as to cover the entire first wiring layer 171. The second wiring layer 172 is, for example, a laminated film made of TiW (titanium - tungsten) / Au (gold).

[0026] Thus, since the material of Cu (copper) is used for the first wiring layer 171 and the material of Au (gold) is used for the second wiring layer 172, it is possible to lower the electrical resistance and suppress the deterioration of the vibration characteristics of the vibration element 30. Also, since the first wiring 17 has 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.

[0027] 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 as compared with the case where the conductive layer is formed only of Au (gold) with low resistance.

[0028] The configurations of the second through-hole 14 and the second wiring 18 are 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.

[0029] The organic resin 23 is formed on the side surface 141 of the second through-hole 14 and on the first surface 11 of the semiconductor substrate 10 around the opening on the first surface 11 side of the second through-hole 14.

[0030] The second wiring 18 is formed on the surface of the second conductive layer 16 exposed from the second through-hole 14, on the surface of the organic resin 23, and on the second region 20 of the first surface 11 of the semiconductor substrate 10 that does not overlap with the organic resin 23.

[0031] The vibration element 30 is joined by the second joining member 22 to a portion of the second wiring 18 disposed in the second region 20. That is, the vibration element 30 can be joined by the second joining member 22 at a position away from the first surface 11 of the semiconductor substrate 10 around the opening of the second through-hole 14 where the organic resin 23 is formed and not overlapping with the organic resin 23.

[0032] As described above, in the vibration device 1 of the present embodiment, the first joining member 21 and the second joining member 22 are arranged in the first region 19 and the second region 20 that do not overlap with the organic resin 23 of the first wiring 17 and the second wiring 18 that 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 joining member 21 and the second joining member 22 that join the vibration element 30. Therefore, when heating and pressing the vibration element 30 via the first joining member 21 and the second joining member 22 on the first wiring 17 and the second wiring 18, disconnection due to deformation, cracks, or the like occurring in the first wiring 17 and the second wiring 18 can be reduced. Thus, a vibration device 1 with excellent electrical connection reliability can be obtained.

[0033] 2. Second Embodiment Next, the vibration device 1a according to the second embodiment will be described with reference to FIGS. 5, 6, and 7. In FIGS. 5 and 7, for the convenience of explaining the internal configuration of the vibration device 1, the state where the lid body 25 is removed is illustrated.

[0034] The vibration device 1a of the present embodiment is the same as the vibration device 1 of the first embodiment, except that the arrangement positions of the first through hole 13 and the second through hole 14 and the configurations of the first wiring 17 and the second wiring 18 are different. Note that the description will focus on the differences from the above-described first embodiment, and the same matters will be denoted by the same reference numerals and their description will be omitted.

[0035] As shown in FIGS. 5 and 6, the vibration device 1a includes a semiconductor substrate 10a, a lid body 25, and a vibration element 30. The semiconductor substrate 10a and the lid body 25 constitute a package 2a that houses the vibration element 30.

[0036] On the first surface 11 of the semiconductor substrate 10a, there are provided a first wiring 17a that electrically connects a first bonding member 21 for bonding the vibration element 30 and a first conductive layer 15, and a second wiring 18a that electrically connects a second bonding member 22 for bonding the vibration element 30 and a second conductive layer 16. The first wiring 17a is disposed at a position overlapping the first through hole 13a in plan view, extends in the plus Y direction, and then extends in the minus X direction. The second wiring 18a is disposed at a position overlapping the second through hole 14a in plan view, extends in the minus Y direction, and then extends in the minus X direction.

[0037] The first bonding member 21 extends in the minus X direction of the first wiring 17a and is disposed in a first region 19a where the organic resin 23 is not disposed. The second bonding member 22 extends in the minus X direction of the second wiring 18 and is disposed in a second region 20a where the organic resin 23 is not disposed.

[0038] The first through hole 13a and the second through hole 14a are arranged between the first joining member 21 and the second joining member 22 in the Y direction. The range where the first through hole 13 and the second through hole 14 are arranged is arranged on the plus side in the X direction, which is the other end 302 side of the vibration element 30 in the X direction, compared to the range where the first joining member 21 and the second joining member 22 are arranged.

[0039] As shown in FIG. 7, in a cross-sectional view, the length between the first surface 11 of the semiconductor substrate 10a and the first portion 61, which is the end on the other end 302 side of the surface of the first joining member 21 on the vibration element 30 side, is defined as H1. Passing through the first portion 61, it contacts 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 at the virtual line 65 that intersects the first surface 11, the distance between the first portion 61 and the second portion 62 is defined as L1. The length between the first surface 11 of the semiconductor substrate 10 and the second portion 62 is defined as H2. When the distance between the first portion 61 and the corner portion 63 on the semiconductor substrate 10 side of the other end 302 of the vibration element 30 is defined as L2, the vibration device 1a of the present embodiment satisfies (H1 - H2) × L2 / H1 > L1. By satisfying (H1 - H2) × L2 / H1 > L1, when the vibration element 30 is joined to the semiconductor substrate 10a or when an impact is applied to the vibration device 1a, 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.

[0040] With such a configuration, it is possible to reduce the contact between the excitation electrode 32 and the first wiring 17a or the second wiring 18a when the vibration element 30 is joined or when an impact is applied, and the same effects as those of the first embodiment can be obtained.

Explanation of Reference Numerals

[0041] 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 joining member, 22... second joining member, 23... organic resin, 25... cover, 26... recess, 27... accommodation space, 28... external terminal, 29... joining member, 30... vibration element, 31... vibration substrate, 32... exciting 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... virtual line, 131, 141... side surface, 171... first wiring layer, 172... second wiring layer, 301... one end, 302... the other end.

Claims

1. A semiconductor substrate including a first surface and a second surface having a front-back relationship with the first surface, and having a first through hole formed therethrough 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 in a plan view; An organic resin formed on a side surface of the first through hole and on the first surface of the semiconductor substrate around an opening on the first surface side of the first through hole; A first wiring formed on a surface of the first conductive layer exposed from the first through hole, on a surface of the organic resin, and on a first region of the first surface of the semiconductor substrate that does not overlap with the organic resin; A vibration element bonded by a first bonding member to a portion of the first wiring disposed in the first region. A vibration device.

2. The vibration element has one end and the other end, and the one end side is bonded by the first bonding member. When the first through hole is disposed on the other end side of the first bonding member. In a cross-sectional view, Let the length between the first surface of the semiconductor substrate and a first portion which is an end on the other end side of the surface of the first bonding member on the vibration element side be H1. Let the distance between the first portion and a second portion of the first wiring on the organic resin formed on the first surface around the first through hole, which is in contact with the second portion and intersects the first surface, be L1. Let the length between the first surface of the semiconductor substrate and the second portion be H2. When the distance between the first portion and a corner portion on the semiconductor substrate side of the other end of the vibration element is L2, (H1 - H2) × L2 / H1 > L1 is satisfied. The vibration device according to Claim 1.

3. Further including a second conductive layer and a second wiring, A second through hole is formed in the semiconductor substrate, penetrating 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 the second through hole in a plan view. The organic resin is formed on a side surface of the second through hole and on the first surface of the semiconductor substrate around an opening on the first surface side of the second through hole. The second wiring is formed on a surface of the second conductive layer exposed from the second through hole, on a surface of the organic resin, and on a second region of the first surface of the semiconductor substrate that does not overlap with the organic resin. The vibration element is bonded by a second bonding member to a portion of the second wiring disposed in the second region. The vibration device according to claim 1.

4. When the direction from one end to the other end of the vibration element is defined as the first direction, and the direction orthogonal to the first direction and along the main surface of the vibration element is defined as the second direction, In a plan view, the first joining member is located on one side in the second direction, In a plan view, the second joining member is located on the other side in the second direction, In the second direction, the first through hole and the second through hole are disposed between the first joining member and the second joining member. The vibration device according to claim 3.

5. When the direction from one end to the other end of the vibration element is defined as the first direction, and the direction orthogonal to the first direction and along the main surface of the vibration element is defined as the second direction, In a plan view, the first joining member is located on one side in the second direction, In a plan view, the second joining member is located on the other side in the second direction, In the first direction, the range where the first through hole and the second through hole are disposed overlaps with the range where the first joining member is disposed, In the first direction, the range where the first through hole and the second through hole are disposed overlaps with the range where the second joining member is disposed. The vibration device according to claim 3.

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

7. 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. The vibration device according to any one of claims 3 to 5.

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

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

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

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