JP2024003642A - Electronic component and method for manufacturing the same, filter and multiplexer - Google Patents

Abstract

To provide an electronic component capable of suppressing deflection of a lid.SOLUTION: An electronic component includes a substrate 10, a functional element provided on the substrate 10, a lid 20 provided above the substrate 10, and an annular layer. The lid 20 and the substrate 10 are bonded to each other, and the functional element is sealed in a gap 26 by the substrate and the lid 20. A first distance L2 in plan view between a first end 34a located on a center 37 side of the substrate 10 in a first region 33 of the annular layer bonded to the substrate 10 and a second terminal 36a located on the center 37 side of the substrate 10 in a second region 35 of the annular layer bonded to the lid 20 is larger than a second distance L4 in plan view between a third end 34b located on the opposite side of the first region 33 with respect to the center 37 of the substrate 10 and a fourth end 36b located on the opposite side of the second region 35 with respect to the center 37 of the substrate 10, and the thickness of the annular layer at a position between the first end 34a and the second end 36a is smaller than the thickness of the annular layer at the first end 34a and larger than the thickness of the annular layer at the second end 36a.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electronic component, a method for manufacturing the same, a filter, and a multiplexer.

A functional element such as an acoustic wave element is provided on a substrate, an annular layer is provided on the substrate to surround the functional element, and a lid is bonded to the annular layer, thereby sealing the functional element in a gap between the lid and the annular layer. Electronic components are known. It is known to provide a columnar body surrounded by a gap in an annular layer and connecting a substrate and a lid (for example, Patent Document 1).

JP 2021-52359 Publication

When pressure is applied to the lid, the lid bends, and as the distance between the lid and the functional element approaches, the characteristics of the functional element deteriorate. By providing a columnar body as in Patent Document 1, deflection of the lid can be suppressed. However, when the columnar bodies are provided, an area for providing functional elements is provided on the upper surface of the substrate, which increases the size of the electronic component.

The present invention has been made in view of the above problems, and an object of the present invention is to suppress the deflection of the lid.

The present invention provides a substrate, a functional element provided on the substrate, a lid provided above the substrate, the lid and the substrate, and the lid seals the functional element in a gap. A first distance in plan view between a first end on the center side of the substrate in a first region bonded to the substrate and a second end on the center side of the substrate in a second region bonded to the lid is, The first end is larger than a second distance in plan view between a third end of the substrate opposite to the center in the first region and a fourth end of the substrate opposite to the center in the second region. and an annular layer having a thickness at a position between the first end and the second end that is smaller than the thickness at the first end and larger than the thickness at the second end.

In the above configuration, the first distance may be 0.1 times or more and 0.7 times or less a third distance between the center of the substrate and the first end in a plan view.

In the above configuration, the first distance may be 2.5 times or more the second distance.

In the above structure, the width of the second region in the direction orthogonal to the direction in which the annular layer extends is at least twice the width of the first region in the orthogonal direction.

In the above configuration, the thickness of the annular layer may be configured to gradually decrease from the first end toward the second end.

In the above structure, the surface of the annular layer on the void side may be a curved surface concave toward the lid.

In the above structure, the lid may include a ferromagnetic element.

In the above structure, the annular layer may be a metal layer.

The above configuration may include a columnar body joined to the substrate and the lid and surrounded by the gap in plan view.

In the above configuration, the functional element may be an acoustic wave element.

The present invention is a filter including the electronic component described above.

The present invention is a multiplexer including the above filter.

The present invention is provided on a substrate provided with a functional element on the surface thereof, and is not provided in an annular region of the substrate that covers the functional element and surrounds the functional element, and that the thickness of the peripheral region increases as the thickness of the peripheral region increases inward. a step of forming a sacrificial layer having a curved surface whose surface in the peripheral region bulges outward; and a step of forming a sacrificial layer on the substrate and the sacrificial layer from at least a region on the functional element side of the annular region of the substrate. forming a mask layer having an opening extending to the peripheral region of the sacrificial layer and provided in the central region of the sacrificial layer; forming an annular layer bonded to the substrate within the opening of the mask layer; and a method for manufacturing an electronic component, including the steps of: removing the sacrificial layer; and bonding a lid that seals the functional element in a gap with the annular layer to the annular layer.

According to the present invention, deflection of the lid can be suppressed.

1(a) and 1(b) are a cross-sectional view and a plan view of an acoustic wave device according to Example 1. FIG. FIG. 2 is a plan view of the acoustic wave element in Example 1. 3(a) to 3(c) are cross-sectional views showing a method of manufacturing an acoustic wave device in Example 1. FIG. 4(a) and 4(b) are cross-sectional views showing a method for manufacturing an acoustic wave device in Example 1. FIG. 5(a) and 5(b) are cross-sectional views showing a method for manufacturing an acoustic wave device in Example 1. FIG. 6(a) and 6(b) are cross-sectional views showing a method for manufacturing an acoustic wave device in Example 1. FIG. FIG. 7 is a cross-sectional view showing a method for manufacturing an acoustic wave device in Example 1. FIGS. 8(a) and 8(b) are diagrams showing the passage characteristics of the multiplexer in simulation 1. 9(a) and 9(b) are cross-sectional views of the elastic wave device in simulation 2. FIGS. 10(a) to 10(c) are diagrams showing the results of simulation 2. FIGS. 11A and 11B are cross-sectional views of acoustic wave devices according to Modifications 1 and 2 of Example 1, respectively. 12(a) and 12(b) are cross-sectional views of an acoustic wave device according to Comparative Example 1. FIG. FIGS. 13A and 13B are cross-sectional views of acoustic wave devices according to Modifications 1 and 2 of Example 1, respectively. 14(a) and 14(b) are a cross-sectional view and a plan view of an acoustic wave device according to a third modification of the first embodiment. 15(a) and 15(b) are a cross-sectional view and a plan view of an acoustic wave device according to a fourth modification of the first embodiment. 16(a) is a cross-sectional view of an acoustic wave device according to a fifth modification of the first embodiment, and FIG. 16(b) is a cross-sectional view of an acoustic wave element according to a fifth modification of the first embodiment. 17(a) is a circuit diagram of a filter according to a second embodiment, and FIG. 17(b) is a circuit diagram of a duplexer according to a first modification of the second embodiment.

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 is an example of an acoustic wave device having an acoustic wave element as a functional element as an electronic component. 1(a) and 1(b) are a cross-sectional view and a plan view of an acoustic wave device according to Example 1. FIG. FIG. 1(a) corresponds to the AA cross section in FIG. 1(b). In FIG. 1(b), illustration of the acoustic wave element 12, metal layer 14, via wiring 16, and terminal 18 is omitted. The dimensions of each member in FIG. 1(a) and FIG. 1(b) do not necessarily correspond. The thickness direction of the substrate 10 is the Z direction, and the plane direction of the substrate 10 is the X direction and the Y direction.

As shown in FIGS. 1(a) and 1(b), the substrate 10 includes a supporting substrate 10a, a piezoelectric layer 10c provided on the supporting substrate 10a, and a piezoelectric layer 10c provided between the supporting substrate 10a and the piezoelectric layer 10c. and an insulating layer 10b. An acoustic wave element 12 and a metal layer 14 are provided as functional elements on the piezoelectric layer 10c. The acoustic wave element 12 is, for example, a surface acoustic wave element. The metal layer 14 functions as a wiring and a pad electrically connected to the acoustic wave element 12. In the peripheral region of the substrate 10 and the region of the substrate 10 where the via wiring 16 is provided, the piezoelectric layer 10c and the insulating layer 10b are removed, and the upper surface of the substrate 10 is the upper surface of the supporting substrate 10a. Via wiring 16 penetrates support substrate 10a. Terminals 18 are provided on the lower surface of the substrate 10. Via wiring 16 electrically connects metal layer 14 and terminal 18 using alternating current or direct current.

An annular layer 30 is provided on the support substrate 10a at the peripheral edge of the substrate 10 so as to surround the acoustic wave element 12. The annular layer 30 includes a metal layer 30a provided on the substrate 10 and a metal layer 30b provided on the metal layer 30a. The annular layer 30 and the lid 20 are bonded together by a bonding layer 24 . Lid 20 and annular layer 30 seal acoustic wave element 12 in air gap 26 . When the annular layer 30 is a metal layer and the lid 20 is a metal plate, the annular layer 30 and the lid 20 function as a shield by supplying a ground potential to the annular layer 30 via via wiring.

A region where the annular layer 30 is bonded to the substrate 10 (support substrate 10a) is a region 33, and a region where the annular layer 30 is bonded to the lid 20 is a region 35. The region 35 is a region where the annular layer 30 and the lid 20 face each other with the bonding layer 24 in between. The inner end of the region 33 (that is, the side toward the center 37 of the substrate 10) is an end 34a, and the outer end (that is, the side opposite to the center 37 of the substrate) is an end 34b. The inner end of the region 35 is an end 36a, and the outer end is an end 36b. The inner surface of the annular layer 30 is 38a, and the outer surface is 38b. The surface 38a is a curved surface recessed toward the annular layer 30 side. A portion of the annular layer 30 between the end 34a and the end 36a is a protruding portion 31. The surface 38b is substantially perpendicular or slightly inclined to the upper surface of the support substrate 10a. In plan view, the end 36b and the end 34b almost match.

The support substrate 10a is, for example, a sapphire substrate, an alumina substrate, a quartz substrate, a crystal substrate, a spinel substrate, a SiC substrate, or a silicon substrate. The insulating layer 10b is, for example, a single layer of a silicon oxide layer, an aluminum oxide layer, a silicon nitride layer, or an aluminum nitride layer, or a stack of these layers. The piezoelectric layer 10c is, for example, a piezoelectric substrate such as a single crystal lithium tantalate substrate, a single crystal lithium niobate substrate, or a single crystal quartz substrate. The single-crystal lithium tantalate substrate and the single-crystal lithium niobate substrate are, for example, rotating Y-cut, X-propagating substrates. The metal layer 14, the via wiring 16, and the terminal 18 are, for example, a single layer of metal layers such as a copper layer, a gold layer, a silver layer, a titanium layer, a nickel layer, a tungsten layer, or a stack of these layers. The lid 20 is a metal layer such as Kovar, or an insulating layer such as a sapphire substrate, an alumina substrate, a quartz substrate, a crystal substrate, a spinel substrate, a SiC substrate, or a silicon substrate. Another functional element may be provided on the lower surface of the lid 20. In this case, another functional element is sealed in the cavity 26.

The bonding layer 24 is, for example, gold-tin solder, tin-silver solder, or tin-silver-copper solder. When the metal layer 30a is to function as a shield, it is preferable to use a material with low resistivity, such as a copper layer or a gold layer. The metal layer 30b is a barrier layer for suppressing diffusion of elements between the bonding layer 24 and the metal layer 30a, and is, for example, a nickel layer. The metal layer 30b may not be provided. The resistivity of metal layer 30a is lower than that of metal layer 30b. The thickness of the metal layer 30a is, for example, five times or more than the thickness of the metal layer 30b. The annular layer 30 may be an insulating layer such as a resin layer. If it is difficult to bond the bonding layer 24 and the lid 20, a metal layer (for example, a gold layer) to which the bonding layer 24 is easily bonded may be provided on the lower surface of the lid 20.

FIG. 2 is a plan view of the acoustic wave element in Example 1. As shown in FIG. 2, the acoustic wave element 12 is a surface acoustic wave resonator or a Lamb wave resonator. An IDT (Interdigital Transducer) 40 and a reflector 42 are formed on the piezoelectric layer 10c. The IDT 40 has a pair of comb-shaped electrodes 40a facing each other. The comb-shaped electrode 40a has a plurality of electrode fingers 40b and a bus bar 40c connecting the plurality of electrode fingers 40b. Reflectors 42 are provided on both sides of the IDT 40. The IDT 40 excites surface acoustic waves in the piezoelectric layer 10c. The wavelength of the elastic wave is approximately equal to the pitch of the electrode fingers 40b of one of the pair of comb-shaped electrodes 40a. That is, the wavelength of the elastic wave is approximately equal to twice the pitch of the electrode fingers 40b of the pair of comb-shaped electrodes 40a. The IDT 40 and the reflector 42 are formed of, for example, an aluminum film, a copper film, or a molybdenum film. A protective film or a temperature compensation film may be provided on the piezoelectric layer 10c so as to cover the IDT 40 and the reflector 42. The elastic wave element 12 includes electrodes that excite elastic waves. Therefore, the acoustic wave element 12 is covered with a void 26 so as not to limit the elastic waves.

[Production method of Example 1]
3A to 7 are cross-sectional views showing a method for manufacturing an acoustic wave device in Example 1. FIG. As shown in FIG. 3(a), an insulating layer 10b is formed on a support substrate 10a. A piezoelectric layer 10c is bonded onto the insulating layer 10b. The support substrate 10a is, for example, a sapphire substrate. The insulating layer 10b is, for example, an aluminum oxide layer and a silicon oxide layer provided on the aluminum oxide layer. The piezoelectric layer 10c is, for example, a lithium tantalate layer. An acoustic wave element 12 is formed on the piezoelectric layer 10c. The piezoelectric layer 10c and the insulating layer 10b in a predetermined region of the substrate 10 are removed. Via wiring 16 is formed in the support substrate 10a in the area where the piezoelectric layer 10c and the insulating layer 10b have been removed. A metal layer 14 is formed on the substrate 10 and the piezoelectric layer 10c.

As shown in FIG. 3(b), a sacrificial layer 50 is formed on the support substrate 10a so as to cover the insulating layer 10b, the piezoelectric layer 10c, the acoustic wave element 12, and the metal layer 14. The sacrificial layer 50 is, for example, a photoresist. As shown in FIG. 3(c), an opening 51 is formed in the sacrificial layer 50. When the sacrificial layer 50 is a photoresist, the opening 51 is formed by, for example, exposure and development. The opening 51 is provided in a region 57 surrounding the acoustic wave element 12 in the substrate 10 . In the central region 58 of the sacrificial layer 50, the thickness of the sacrificial layer 50 is approximately constant, and in the peripheral region 56 of the sacrificial layer 50, the thickness of the sacrificial layer 50 increases as the surface of the sacrificial layer 50 goes inward. It is a curved surface that looks like this. For example, when the sacrificial layer 50 is a photoresist, the surface of the sacrificial layer 50 becomes curved by heat treatment.

As shown in FIG. 4A, a seed layer 30c is formed on the support substrate 10a and the sacrificial layer 50. The seed layer 30c is a layer that serves as a plating seed, and is, for example, a titanium layer and a copper layer from the substrate 10 side. A mask layer 52 is formed on the seed layer 30c. Mask layer 52 is, for example, photoresist. As shown in FIG. 4(b), an opening 53 is formed in the mask layer 52. The opening 53 is provided from the region 57 to the peripheral region 56, and the mask layer 52 in the central region 58 remains. When the mask layer 52 is a photoresist, the opening 51 is formed by, for example, exposure and development.

As shown in FIG. 5A, metal layers 30a, 30b and bonding layer 24 are formed in opening 53 using electric field plating by supplying current from seed layer 30c. The metal layer 30a is, for example, a copper layer, the metal layer 30b is, for example, a nickel layer, and the bonding layer 24 is, for example, a gold-tin layer. When the side surfaces of the mask layer 52 are inclined with respect to the normal direction of the upper surface of the substrate 10 , part of the side surfaces of the annular layer 30 and the bonding layer 24 are inclined with respect to the normal direction of the upper surface of the substrate 10 . Depending on the conditions of the electrolytic plating method, the center portions of the upper surfaces of each of the metal layers 30a, 30b and the bonding layer 24 may have a curved shape that protrudes upward. As shown in FIG. 5(b), the mask layer 52 is removed. Seed layer 30c is removed using bonding layer 24 and metal layers 30b and 30a as masks. Thereby, an annular layer 30 is formed by the metal layers 30a, 30b and the seed layer 30c. The inner surface 38a of the annular layer 30 is a curved surface along the opening 51 of the sacrificial layer 50, and the outer surface 38b of the annular layer 30 is a surface along the side surface of the opening 53 of the mask layer 52. In FIG. 1A and the like, illustration of the seed layer 30c is omitted.

As shown in FIG. 6A, the substrate 10 is heated so that the temperature of the bonding layer 24 is equal to or higher than the melting point. The lid 20 is pressed against the bonding layer 24 from above. Bonding layer 24 is bonded to lid 20 . The acoustic wave element 12 is sealed in the air gap 26 by the lid 20 and the annular layer 30 . The lid 20 is, for example, a Kovar layer. As shown in FIG. 6(b), the lower surface of the support substrate 10a is ground or polished, for example. As a result, the supporting substrate 10a becomes thinner, and the via wiring 16 is exposed from the lower surface of the supporting substrate 10a. Terminals 18 connected to via wiring 16 are formed on the lower surface of support substrate 10a.

As shown in FIG. 7, the lid 20 and substrate 10 are cut in the direction of arrow 54. For cutting, a laser dicing method or a dicing method using a blade is used. Through the above steps, the acoustic wave device in Example 1 is manufactured.

[Simulation 1]
When sealing the acoustic wave device using mold resin, pressure is applied to the lid 20. In this way, when pressure is applied to the lid 20, the lid flexes and the lid 20 approaches the acoustic wave element 12. As a result, the characteristics of the acoustic wave element 12 may deteriorate. When a multiplexer using the acoustic wave element 12 was formed on the top surface of the piezoelectric layer 10c, the characteristics of the multiplexer were simulated by changing the distance between the lid 20 and the piezoelectric layer 10c.

In simulation 1, a duplexer having a reception filter and a transmission filter for band 7 of LTE (Long Term Evolution) was used as the multiplexer. The receiving filter and the transmitting filter were ladder type filters having a surface acoustic wave resonator using a lithium tantalate layer as the piezoelectric layer 10c. The lid 20 was made of Kovar (an alloy of iron, nickel, and cobalt) with a thickness of 20 μm. The distance D between the top surface of the piezoelectric layer 10c and the bottom surface of the lid 20 was set to 3.8 μm, 8.8 μm, and 58.8 μm. The lid 20 was set at a ground potential, and the influence of ferromagnetic elements (iron, nickel, and cobalt) within the lid 20 was also taken into consideration.

FIGS. 8(a) and 8(b) are diagrams showing the passage characteristics of the multiplexer in simulation 1. FIG. 8(b) is an enlarged view of FIG. 8(a). FIGS. 8(a) and 8(b) show the pass characteristics of the transmission filter TxF and the reception filter RxF. TxB indicates a band 7 transmission band, and RxB indicates a band 7 reception band. As shown in FIGS. 8A and 8B, the transmission band TxB and the reception band RxB overlap with the passband of the transmission filter TxF and the reception filter RxF, respectively. When the distance D is 58.8 μm, the passband insertion loss of both the transmission filter TxF and the reception filter RxF is small. When the distance D becomes 8.8 μm, the insertion loss within the passband of both the transmission filter TxF and the reception filter RxF becomes large, and a ripple Ri is formed. When the distance D becomes 3.8 μm, the ripple Ri within the passband of both the transmission filter TxF and the reception filter RxF becomes larger.

The reason why the insertion loss within the passband of both the transmission filter TxF and the reception filter RxF increases as the lid 20 approaches the multiplexer is considered to be the influence of the magnetic field caused by the ferromagnetic element of the lid 20. Furthermore, the influence of parasitic capacitance between the lid 20 and the multiplexer is also considered.

As in simulation 1, when the lid 20 includes a ferromagnetic element, the characteristics of the acoustic wave element 12 deteriorate when the lid 20 approaches the elastic wave element 12 due to the influence of the magnetic field caused by the ferromagnetic element. When the lid 20 is made of metal, the characteristics of the acoustic wave element 12 deteriorate when the lid 20 approaches the acoustic wave element 12 due to parasitic capacitance between the lid 20 and the acoustic wave element 12. Further, when the lid 20 comes into contact with the acoustic wave element 12, the elastic wave element 12 is short-circuited. If the lid 20 is an insulator, there is a possibility that the acoustic wave element 12 will be destroyed if the lid 20 comes into contact with the acoustic wave element 12.

[Simulation 2]
The distance between the lid 20 and the annular layer 30 and the piezoelectric layer 10c when pressure is applied to the lid 20 was simulated using a two-dimensional finite element method. 9(a) and 9(b) are cross-sectional views of the elastic wave device in simulation 2. 9(a) shows the lid 20 before pressure is applied, and FIG. 9(b) shows the lid 20 with pressure applied. As shown in FIGS. 9(a) and 9(b), in simulation 2, a straight line passing through the center 37 of the substrate 10 and the lid 20 was used as a mirror surface condition, and the simulation was performed in a half region of the acoustic wave device in the X direction. Insulating layer 10b is not provided.

As shown in FIG. 9A, before pressure is applied to the lid 20, the thickness of the support substrate 10a is T10a, and the thickness of the piezoelectric layer 10c is T10c. The length of the support substrate 10a in the X direction (the distance between the center 37 of the support substrate 10a and the end of the support substrate 10a) is L0. The width of the region 33 where the annular layer 30 is bonded to the support substrate 10a is Wa. The width of the region 35 where the annular layer 30 joins the lid 20 is Wb. The distance in the X direction between the end 34a of the region 33 on the center 37 side and the center 37 is L1. The distance in the X direction between the end 34a of the region 33 on the center 37 side and the end 36a of the region 35 on the center 37 side (that is, the width of the protruding portion 31) is L2. The distance between the end 34a and the +X side end 39 of the piezoelectric layer 10c is L3. The thickness of the metal layer 30a at the end 34a is Ta. The thickness of the metal layer 30a at the end 36a is Tb. The thickness of the metal layer 30a at the midpoint between the ends 34a and 36a (at a distance L2/2 from the end 34a) is Td. The thicknesses of metal layer 30b, bonding layer 24, and lid 20 are T30b, T24, and T20, respectively. The gap between the upper surface of the piezoelectric layer 10c and the lower surface of the lid 20 at the center 37 is G1a. The gap between the upper surface of the piezoelectric layer 10c and the lower surface of the metal layer 30b at the end 36a is G2a. The gap between the upper surface of the piezoelectric layer 10c and the lower surface of the metal layer 30a at the end 39 of the piezoelectric layer 10c is G3a.

As shown in FIG. 9(b), pressure is uniformly applied to the upper surface of the lid 20 as indicated by an arrow 55. The pressure deforms the lid 20 and the annular layer 30. After deformation, the gap between the upper surface of the piezoelectric layer 10c and the lower surface of the lid 20 at the center 37 is G1b. The gap between the upper surface of the piezoelectric layer 10c and the lower surface of the metal layer 30b at the end 36a is G2b. The gap between the upper surface of the piezoelectric layer 10c and the lower surface of the metal layer 30a at the end 39 is G3b.

The dimensions and materials of each member in simulation 2 are as follows.
Support substrate 10a: length L0 is 492 μm, thickness T10a is 75 μm, material is single crystal sapphire Piezoelectric layer 10c: thickness T10c is 6 μm, material is lithium tantalate, distance L3 is 10.5 μm
Metal layer 30a: Thickness Ta is 27 μm, width Wa is 26 μm, L1 is 466 μm, material is copper Metal layer 30b: thickness T30b is 2.5 μm, material is nickel Bonding layer 24: thickness T24 is 5 μm, material is gold Tin lid 20: length L0 is 492 μm, thickness T20 is 30 μm, material is Kovar The cross section of surface 38a of metal layer 30a is 1/4 of an ellipse.

Table 1 shows the Young's modulus, Poisson's ratio, bulk modulus, and shear modulus of each material.

The simulation was performed by changing the thickness Tb at the end 36a of the metal layer 30a to 1 μm, 2 μm, 4 μm, and 6 μm, and changing the distance ratio L2/L1 from 0.2 to 0.65. The simulation was performed with a pressure uniformly applied to the upper surface of the lid 20 of 3 MPa, a mirror surface condition at the center 37, and a fixed condition at the region 33, taking only elastic deformation into consideration. Since the region 33 is set as a fixed condition, deformation of the substrate 10 is not taken into account.

FIGS. 10(a) to 10(c) are diagrams showing the results of simulation 2. 10(a) shows gaps G1a, G1b and ΔG1=G1a-G1b, FIG. 10(b) shows gaps G2a, G2b and ΔG2=G2a-G2b, and FIG. 10(c) shows gaps G3a, G3b and ΔG3=G3a−G3b are shown. Blank columns are not simulated.

As shown in FIG. 10(a), in any case of thickness Tb, when L2/L1 is increased, ΔG1 becomes smaller. That is, when L2/L1 is increased, the gap G1b between the lid 20 and the piezoelectric layer 10c after the lid 20 is deformed becomes larger. In either case of L2/L1, when the thickness Tb is increased, ΔG1 becomes smaller and G1b becomes larger. In this way, from the viewpoint of increasing the gap G1b, it is better that L2/L1 is larger and the thickness Tb is larger. When the lid 20 contains a ferromagnetic element, as in simulation 1, the gap G1b is preferably larger. For example, in order to make the gap G1b 15 μm or more, L2/L1 is preferably 0.25 or more.

As shown in FIG. 10(b), in any case of the thickness Tb, when L2/L1 is increased, ΔG2 becomes larger and the gap G2b becomes smaller. In either case of L2/L1, when the thickness Tb is increased, ΔG2 becomes smaller and G2b becomes larger. Thus, from the viewpoint of increasing the gap G2b, it is better that L2/L1 is smaller and the thickness Tb is larger. This is because the position of the end 36a approaches the center 37 as L2/L1 increases. When the metal layer 30b contains a ferromagnetic element, as in simulation 1, it is better for the gap G2b to be large. For example, in order to make the gap G2b 15 μm or more, L2/L1 is preferably 0.25 or more.

As shown in FIG. 10(c), in any case of the thickness Tb, when L2/L1 is increased, ΔG3 becomes larger and the gap G3b becomes smaller. In any case of L2/L1, when the thickness Tb is increased, ΔG3 becomes smaller and G3b becomes smaller. Thus, from the viewpoint of increasing the gap G3b, it is better that L2/L1 is smaller and the thickness Tb is smaller. This is because when L2/L1 is small, the lid 20 near the center 37 bends a lot, but near the end 39 the lid 20 does not bend much, and when L2/L1 is large, the lid 20 near the center 37 does not bend much. This is thought to be because the lid 20 bends near the edge 39 of the object. Furthermore, it is thought that this is because the gap G3a at the end 39 becomes smaller as L2/L1 becomes larger before applying pressure. If the metal layer 30a does not contain a ferromagnetic element, the gap G3b will be larger than 0 μm so that the metal layer 30a does not come into contact with the piezoelectric layer 10c. For example, in order to make the gap G3b larger than 0 μm, L2/L1 is preferably 0.60 or less.

[Modification 1 of Example 1]
FIGS. 11A and 11B are cross-sectional views of acoustic wave devices according to Modifications 1 and 2 of Example 1, respectively. The illustration of the acoustic wave element 12, metal layer 14, via wiring 16, and terminal 18 is omitted. As shown in FIG. 11A, in the first modification of the first embodiment, the surface 38a of the metal layer 30a on the center 37 side in the protruding portion 31 is stepped. The thickness of the metal layer 30a of the portion 31b on the center 37 side of the protruding portion 31 is Tb, and the thickness of the outer portion 31a of the protruding portion 31 is Tc. Thickness Tc is smaller than thickness Ta of metal layer 30a in region 33 and larger than thickness Tb. As in the first modification of the first embodiment, the surface 38a may have a stepped shape. The other configurations are the same as those in the first embodiment, and their explanation will be omitted.

[Modification 2 of Example 1]
As shown in FIG. 11(b), in the second modification of the first embodiment, the surface 38a of the metal layer 30a on the center 37 side in the protruding portion 31 is a flat surface. As in the second modification of the first embodiment, the surface 38a may be a flat surface. The other configurations are the same as those in Example 1, and their explanation will be omitted.

[Comparative example 1]
12(a) and 12(b) are cross-sectional views of an acoustic wave device according to Comparative Example 1. FIG. 5 is a diagram showing a case where uniform pressure is applied to the upper surface of the lid 20. FIG. As shown in FIGS. 12A and 12B, in Comparative Example 1, the thickness Tb or Tc of the metal layer 30a at the protruding portion 31 is uniform. The thickness Tb in FIG. 12(a) is smaller than the thickness Tc in FIG. 12(b). As shown in FIG. 12A, when the thickness Tb is small, the lid 20 tends to bend when pressure is applied to the lid 20. Therefore, the gap G1b between the piezoelectric layer 10c and the lid 20 at the center 37 becomes smaller. The gap G4b between the piezoelectric layer 10c and the lid 20 at the end 36a is large. In this way, the lid 20 approaches the piezoelectric layer 10c at the center 37, and the characteristics of the acoustic wave element deteriorate.

As shown in FIG. 12(b), when the thickness Tc is large, even if pressure is applied to the lid 20, the protruding portion 31 can suppress the lid 20 from bending. Thereby, the gap G1b at the center 37 can be increased. However, since the thickness Tc is large, the gap G4b at the end 36a becomes small. Thereby, there is a possibility that the protruding portion 31 comes into contact with the piezoelectric layer 10c. In Comparative Example 1, when the thickness Tb is decreased, the gap G1b is decreased, and when the thickness Tc is increased, the gap G4b is decreased.

FIGS. 13A and 13B are cross-sectional views of acoustic wave devices according to Modifications 1 and 2 of Example 1, respectively. 5 is a diagram showing a case where uniform pressure is applied to the upper surface of the lid 20. FIG. As shown in FIG. 13(a), in the first modification of the first embodiment, the thickness Tc of the metal layer 30a in the portion 31a is larger than the thickness Tb in FIG. 12(a). As a result, the deflection of the lid 20 is smaller than in FIG. 12(a), and the gap G1b at the center 37 can be made larger than in FIG. 12(a). Furthermore, since the thickness Tb of the metal layer 30a in the portion 31b is smaller than the thickness Tc in FIG. 12(b), the gap G4b at the end 36a can be made larger than in FIG. 12(b). Further, the smallest gap G5b between the piezoelectric layer 10c and the annular layer 30 can also be made larger than the gap G4b in FIG. 12(b).

As shown in FIG. 13(b), in the second modification of the first embodiment, the thickness of the metal layer 30a at the protruding portion 31 changes uniformly. As a result, the deflection of the lid 20 is smaller than in FIG. 12(a), and the gap G1b at the center 37 can be made larger than in FIG. 12(a). Furthermore, since the thickness Tb of the metal layer 30a at the end 36a is smaller than the thickness Tc in FIG. 12(b), the gap G4b at the end 36a can be made larger than that in FIG. 12(b). When the surface 38a is a flat surface, the gap G3b at the end 39 of the piezoelectric layer 10c becomes smaller.

In Example 1, the surface 38a is a curved surface as shown in FIG. 9(b). Therefore, the gap G3b at the end 39 can be made larger than that shown in FIG. 13(b).

As described above, according to the first embodiment and the first and second variations thereof, the first distance L2 is between the first end 34a on the center 37 side of the substrate 10 in the first region 33 where the annular layer 30 is bonded to the substrate 10. , is the distance in plan view from the second end 36a on the center 37 side in the second region 35 where the annular layer 30 is joined to the lid 20. The second distance L4 is the distance between the third end 34b on the opposite side of the center 37 in the first region 33 and the fourth end 36b on the opposite side of the center 37 in the second region 35 in plan view. At this time, the first distance L2 is larger than the second distance L4. Thereby, when pressure is applied to the lid 20, the deflection of the lid 20 can be reduced. The thickness of the annular layer 30 at a location between the first end 34a and the second end 36a is less than the thickness of the annular layer 30 at the first end 34a and greater than the thickness of the annular layer 30 at the second end 36a. Thereby, the deflection of the lid 20 can be reduced. Furthermore, as explained in FIGS. 13(a) and 13(b), gaps G1b and G4b can be made larger than in comparative example 1. Furthermore, the number of columnar bodies can be reduced compared to Patent Document 1. Thereby, the area where the acoustic wave element 12 is provided on the upper surface of the substrate 10 can be enlarged. Therefore, the area of the substrate 10 can be reduced, and the acoustic wave device can be made smaller.

From the viewpoint of suppressing deflection of the lid 20, the first distance L2 is preferably 2.5 times or more, more preferably 3 times or more, and even more preferably 5 times or more the second distance L4. The width Wb of the second region 35 (the width in the direction perpendicular to the direction in which the annular layer 30 extends) is preferably at least twice the width Wa of the first region 33 (the width in the direction perpendicular to the direction in which the annular layer 30 extends), It is more preferably 3 times or more, and even more preferably 5 times or more. Note that the second distance L4 may be 0. That is, the outer surface 38b of the annular layer 30 may be perpendicular to the upper surface of the substrate 10. In this case as well, the first distance L2 is assumed to be larger than the second distance L4.

As in simulation 2, the first distance L2 is preferably 0.1 times or more, more preferably 0.2 times or more, and 0.3 times the third distance L1 between the center 37 and the first end 34a in plan view. The above is more preferable. Thereby, as shown in FIG. 10(a), the gap G1b between the lid 20 and the piezoelectric layer 10c can be increased. The first distance L2 is preferably 0.7 times or less than the third distance L1, more preferably 0.6 times or less, and even more preferably 0.5 times or less. Thereby, as shown in FIG. 10(c), the gaps G3b to G5b between the annular layer 30 and the piezoelectric layer 10c can be increased.

As in the first embodiment and the second modification thereof, the thickness of the annular layer 30 gradually decreases from the first end 34a toward the second end 36a. Thereby, deflection of the lid 20 can be suppressed.

As in the first embodiment, the surface 38a of the annular layer 30 on the void 26 side is a curved surface concave toward the lid 20. Thereby, as shown in FIG. 9(b), the gap G3b can be made larger than in FIG. 13(b). The thickness of the annular layer 30 at the midpoint of the first end 34a and the second end 36a in plan view (Td+the thickness of the metal layer 30b) is the thickness of the annular layer 30 at the first end 34a and the thickness at the second end 36a. The difference in thickness of the annular layer 30 (Ta-Tb) is preferably smaller than 0.5 times, more preferably 0.4 times or less, and even more preferably 0.3 times or less. Thereby, the gap G5b can be increased. The thickness of the annular layer 30 (the thickness of the Td+metal layer 30b) is preferably 0.05 times or more, more preferably 0.1 times or more, the thickness of Ta--Tb. Thereby, the deflection of the lid 20 can be reduced.

As a method for manufacturing an acoustic wave device in which the surface 38a is a curved surface, as shown in FIG. 3C, a sacrificial layer 50 covering the acoustic wave element 12 is formed on the substrate 10 on which the acoustic wave element 12 is provided. . The sacrificial layer 50 is not provided in a region 57 (annular region) of the substrate 10 surrounding the acoustic wave element 12. The thickness of the peripheral region 56 of the sacrificial layer 50 becomes smaller toward the inside, and the surface of the sacrificial layer 50 in the peripheral region 56 swells outward. As shown in FIG. 4(b), a mask layer 52 is formed on the substrate 10 and the sacrificial layer 50. The mask layer 52 has an opening 53 extending from at least a region 57 of the substrate 10 on the acoustic wave element 12 side to a peripheral region 56 of the sacrificial layer 50 and is provided in a central region 58 of the sacrificial layer 50 . As shown in FIG. 5A, an annular layer 30 bonded to the substrate 10 is formed within the opening 53 of the mask layer 52. As shown in FIG. 5(b), the sacrificial layer 50 and the mask layer 52 are removed. As shown in FIG. 6(a), the lid 20 is joined to the annular layer 30. As a result, the surface 38a of the annular layer 30 becomes a curved surface concave toward the lid.

As in the first modification of the first embodiment, the surface 38a of the annular layer 30 may have a stepped shape. In the first modification of the first embodiment, the annular layer 30 has two thicknesses, but the annular layer 30 may have three or more thicknesses.

When the lid 20 contains a ferromagnetic element, as in simulation 1, the characteristics of the acoustic wave element 12 tend to deteriorate. Therefore, it is preferable to suppress the bending of the lid 20 by providing the protruding portion 31. Ferromagnetic elements are, for example, iron, nickel and cobalt. The concentration of the ferromagnetic element in the lid 20 is preferably 50 atom % or more, more preferably 80 atom % or more.

When the annular layer 30 is a metal layer, when the annular layer 30 contacts the piezoelectric layer 10c, the acoustic wave element 12 is electrically short-circuited. Therefore, it is preferable that the thickness of the annular layer 30 at the position between the ends 34a and 36a is smaller than the thickness of the annular layer 30 at the end 34a and larger than the thickness of the annular layer 30 at the end 36a.

The substrate 10 includes a support substrate 10a and a piezoelectric layer 10c provided on the support substrate 10a. The piezoelectric layer 10c in the region where the annular layer 30 was provided is removed, and the acoustic wave element 12 is provided on the piezoelectric layer 10c. In such a structure, the piezoelectric layer 10c and the annular layer 30 are likely to come into contact with each other. Therefore, it is preferable that the thickness of the annular layer 30 at the position between the ends 34a and 36a is smaller than the thickness of the annular layer 30 at the end 34a and larger than the thickness of the annular layer 30 at the end 36a.

[Modification 3 of Example 1]
14(a) and 14(b) are a cross-sectional view and a plan view of an acoustic wave device according to a third modification of the first embodiment. FIG. 14(a) corresponds to the AA cross section in FIG. 14(b). The illustration of the acoustic wave element 12, metal layer 14, via wiring 16, and terminal 18 is omitted. The dimensions of each member in FIG. 14(a) and FIG. 14(b) do not necessarily correspond. As shown in FIGS. 14(a) and 14(b), in the third modification of the first embodiment, a columnar body 32 (pillar) surrounded by a void 26 is provided. The piezoelectric layer 10c is removed in the region where the columnar bodies 32 are provided. The columnar body 32 includes a metal layer 30a provided on the support substrate 10a and a metal layer 30b provided on the metal layer 30a. The metal layers 30a and 30b of the columnar body 32 and the metal layers 30a and 30b of the annular layer 30 are formed by the same manufacturing process and are made of the same material. The columnar body 32 and the lid 20 are bonded by a bonding layer 24. The columnar body 32 is provided at or near the center 37 of the substrate 10 in plan view. The other configurations are the same as those in the first embodiment, and their explanation will be omitted. By providing the columnar bodies 32, deflection of the lid 20 can be further suppressed.

[Modification 4 of Example 1]
15(a) and 15(b) are a cross-sectional view and a plan view of an acoustic wave device according to a fourth modification of the first embodiment. FIG. 15(a) corresponds to the AA cross section in FIG. 15(b). The illustration of the acoustic wave element 12, metal layer 14, via wiring 16, and terminal 18 is omitted. The dimensions of each member in FIGS. 15(a) and 15(b) do not necessarily correspond. As shown in FIGS. 15(a) and 15(b), in the fourth modification of the first embodiment, two columnar bodies 32 surrounded by a gap 26 are provided. The planar shape of the substrate 10 is a rectangle with long sides in the X direction and short sides in the Y direction. The columnar bodies 32 are arranged in the X direction at or near the center of the substrate 10 in the Y direction. The other configurations are the same as the third modification of the first embodiment, and the explanation will be omitted.

As in Modifications 3 and 4 of Embodiment 1, a columnar body 32 may be provided that is joined to the substrate 10 and the lid 20 and surrounded by the void 26 in plan view. Thereby, deflection of the lid 20 can be further suppressed. When providing one columnar body 32, it is preferable that the columnar body 32 be provided near the center 37 of the substrate 10. When a plurality of columnar bodies 32 are provided, it is preferable that the plurality of columnar bodies 32 are arranged at the center in the short side direction of the substrate 10 in the long side direction.

As an example, when the width of the substrate 10 in the long side direction is 1000 μm or less, the columnar bodies 32 are not provided as in the first embodiment. When the width of the substrate 10 in the long side direction is 1000 μm or more and 2000 μm or less, one columnar body 32 is provided as in the third modification of the first embodiment. When the width of the substrate 10 in the long side direction is 2000 μm or more, a plurality of columnar bodies 32 are provided as in the fourth modification of the first embodiment.

[Modification 5 of Example 1]
FIG. 16(a) is a cross-sectional view of an acoustic wave device according to a fifth modification of the first embodiment. As shown in FIG. 16(a), an acoustic wave element 12a is provided on a substrate 10. The substrate 10 is, for example, a sapphire substrate, an alumina substrate, a quartz substrate, a crystal substrate, a spinel substrate, a SiC substrate, or a silicon substrate. The other configurations are the same as in FIG. 1(a) of the first embodiment.

FIG. 16(b) is a cross-sectional view of an acoustic wave element in a fifth modification of the first embodiment. As shown in FIG. 16(b), in the acoustic wave element 12a, which is a piezoelectric thin film resonator, a piezoelectric film 46 is provided on the substrate 10. A lower electrode 44 and an upper electrode 48 are provided so as to sandwich the piezoelectric film 46 therebetween. A gap 45 is formed between the lower electrode 44 and the substrate 10. A region where the lower electrode 44 and the upper electrode 48 face each other with at least a portion of the piezoelectric film 46 in between is a resonance region 47 . In the resonance region 47, the lower electrode 44 and the upper electrode 48 excite an elastic wave in the thickness longitudinal vibration mode or the thickness shear vibration mode within the piezoelectric film 46. The lower electrode 44 and the upper electrode 48 are, for example, metal films such as ruthenium films. The piezoelectric film 46 is, for example, an aluminum nitride film, a lithium tantalate film, or a lithium niobate film. Instead of the void 45, an acoustic reflection film that reflects elastic waves may be provided. The other configurations are the same as those in Example 1, and their explanation will be omitted. Like Modification 5 of Embodiment 1, in Embodiment 1 and Modifications 1 to 4 thereof, the acoustic wave element may be a piezoelectric thin film resonator.

In Embodiment 1 and its modifications, the example of the acoustic wave elements 12 and 12a (surface acoustic wave resonator or piezoelectric thin film resonator) was explained as the functional element, but the functional element may be a passive element such as an inductor or a capacitor, or a transistor. The active device may be an active device including , or a MEMS (Micro Electro Mechanical Systems) device.

FIG. 17(a) is a circuit diagram of a filter according to the second embodiment. As shown in FIG. 17(a), one or more series resonators S1 to S4 are connected in series between the input terminal Tin and the output terminal Tout. One or more parallel resonators P1 to P4 are connected in parallel between the input terminal Tin and the output terminal Tout. The acoustic wave elements 12 and 12a of the first embodiment and its modifications can be used for at least one of the series resonators S1 to S4 and the parallel resonators P1 to P4. The number of series resonators and parallel resonators can be set as appropriate. Although the filter has been described using a ladder filter as an example, the filter may be a multimode filter.

FIG. 17(b) is a circuit diagram of a duplexer according to a first modification of the second embodiment. As shown in FIG. 17(b), a transmission filter 60 is connected between the common terminal Ant and the transmission terminal Tx. A reception filter 62 is connected between the common terminal Ant and the reception terminal Rx. The transmission filter 60 passes a signal in the transmission band among the high-frequency signals inputted from the transmission terminal Tx to the common terminal Ant as a transmission signal, and suppresses signals of other frequencies. The reception filter 62 passes a signal in the reception band among the high-frequency signals inputted from the common terminal Ant to the reception terminal Rx as a reception signal, and suppresses signals at other frequencies. At least one of the transmission filter 60 and the reception filter 62 can be the filter of the second embodiment.

Although a duplexer has been described as an example of a multiplexer, a triplexer or a quadplexer may also be used.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention as described in the claims. Changes are possible.

10 Substrate 10a Support substrate 10b Insulating layer 10c Piezoelectric layer 12, 12a Acoustic wave element 14, 30a, 30b Metal layer 16 Via wiring 18 Terminal 20 Lid 24 Bonding layer 26 Gap 30 Annular layer 31 Projecting portion 32 Column 33, 35 Region 34a , 34b, 36a, 36b, 39 End 37 Center 38a, 38b Surface 50 Sacrificial layer 51, 53 Opening 52 Mask layer 60 Transmission filter 62 Reception filter

Claims (13)

A substrate and
a functional element provided on the substrate;
a lid provided above the substrate;
the lid and the substrate are bonded, the functional element is sealed in a gap with the lid, a first end on the center side of the substrate in a first region bonded to the substrate and a second end bonded to the lid; The first distance in a plan view between the second end of the substrate on the center side of the region is the distance between the third end of the substrate on the opposite side of the center in the first region and the center of the substrate in the second region. The thickness at a position between the first end and the second end is greater than the second distance in plan view from the opposite fourth end, and the thickness at the second end is smaller than the thickness at the first end. an annular layer greater than the thickness;
Electronic components with. The electronic component according to claim 1, wherein the first distance is 0.1 times or more and 0.7 times or less a third distance between the center of the substrate and the first end in a plan view. The electronic component according to claim 1 or 2, wherein the first distance is 2.5 times or more the second distance. 3. The electronic component according to claim 1, wherein the width of the second region in the direction orthogonal to the direction in which the annular layer extends is at least twice the width of the first region in the orthogonal direction. The electronic component according to claim 1 or 2, wherein the thickness of the annular layer gradually decreases from the first end toward the second end. 6. The electronic component according to claim 5, wherein the surface of the annular layer on the void side is a curved surface concave toward the lid. The electronic component according to claim 1 or 2, wherein the lid contains a ferromagnetic element. The electronic component according to claim 1 or 2, wherein the annular layer is a metal layer. The electronic component according to claim 1 or 2, further comprising a columnar body joined to the substrate and the lid and surrounded by the gap in plan view. The electronic component according to claim 1 or 2, wherein the functional element is an acoustic wave element. A filter comprising the electronic component according to claim 10. A multiplexer comprising a filter according to claim 11. On a substrate provided with a functional element on the surface thereof, the annular region of the substrate covering the functional element and surrounding the functional element is not provided, and the thickness of the peripheral region becomes smaller as it goes inward; forming a sacrificial layer whose surface in the peripheral region is a curved surface that bulges outward;
A mask layer is formed on the substrate and the sacrificial layer, the mask layer having an opening extending from at least a region on the functional element side of the annular region of the substrate to the peripheral region of the sacrificial layer and provided in a central region of the sacrificial layer. The process of
forming an annular layer bonded to the substrate within the opening of the mask layer;
removing the mask layer and the sacrificial layer;
a step of joining a lid that seals the functional element in a gap with the annular layer to the annular layer;
A method of manufacturing electronic components including

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