Electronic components, filters and multiplexers

Abstract

To provide an electronic component capable of suppressing the lack of a metal bonding layer between an annular metal layer and a lid.SOLUTION: An electronic component comprises a substrate 10, a functional element provided on the substrate 10, an annular metal layer 30 provided on the substrate 10 so as to surround the functional element in a plan view, a lid 20 provided on the annular metal layer 30 and sealing the functional element in a void 26 with the annular metal layer 30, a convex portion 34 provided on a first surface of the annular metal layer 30 opposite the lid 20 or on a second surface of the lid 20 opposite the annular metal layer 30 and extending in the direction of extension of the annular metal layer 30 in a plan view, and a metal bonding layer 24 bonding the first side and the second side at least on the center side of the substrate 10 of the convex portion 34.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electronic component, a method for manufacturing the same, a filter, and a multiplexer.

Background Art

[0002] There is known an electronic component in which a functional element such as an elastic wave element is provided on a substrate, an annular metal layer is provided on the substrate so as to surround the functional element, and a lid is joined onto the annular metal layer, and the functional element is sealed in a void by the lid and the annular metal layer (for example, Patent Documents 1 to 4).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] When joining the lid and the annular metal layer by melting a bonding material such as solder, the melted bonding material tends to gather where the area of the annular metal layer is large. Therefore, there is a possibility that a portion where the bonding layer between the annular metal layer and the lid is locally insufficient may occur.

[0005] The present invention has been made in view of the above problems, and an object thereof is to suppress a shortage of the metal bonding layer between the annular metal layer and the lid.

Means for Solving the Problems

[0006] The present invention relates to an electronic component comprising: a substrate; a functional element provided on the substrate; an annular metal layer provided on the substrate so as to surround the functional element in a plan view; a lid provided on the annular metal layer and sealing the functional element within a gap with the annular metal layer; a convex portion provided on a first surface of the annular metal layer facing the lid or on a second surface of the lid facing the annular metal layer, extending in the direction in which the annular metal layer extends in a plan view; and a metal bonding layer that joins the first surface and the second surface at least on the center side of the convex portion of the substrate.

[0007] In the above configuration, the protrusion can be provided in a portion of the region in which the annular metal layer surrounds the functional element, and not in the remaining portion of the region.

[0008] In the above configuration, the protrusions can be provided at locations within the region corresponding to the corners of the substrate.

[0009] In the above configuration, the annular metal layer comprises a first portion and a second portion that is wider in a direction perpendicular to the direction extending from the first portion, and the protrusion is provided in the second portion of the region.

[0010] In the above configuration, the planar shape of the annular metal layer is a substantially rectangular shape provided along the outer circumference of the substrate, the annular metal layer comprises a first portion provided on the first side of the substantially rectangular shape, and a second portion provided on the first side and wider in a direction perpendicular to the direction extending from the first portion, and the convex portion is provided on a third portion of the second side of the substantially rectangular shape opposite to the first side, corresponding to the second portion.

[0011] In the above configuration, the width of the protrusion in the direction perpendicular to the direction of extension can be set to be 1 / 2 or less of the width of the annular metal layer in the direction perpendicular to that direction.

[0012] In the above configuration, the thickness of the metal bonding layer between the annular metal layer or the lid and the convex portion can be set to be not more than the height of the convex portion.

[0013] In the above configuration, on the side of the convex portion opposite to the center of the substrate, a configuration can be adopted in which the metal bonding layer is not provided at least partially between the annular metal layer and the lid.

[0014] In the above configuration, a configuration can be adopted in which at least a part of the side surface of the lid substantially coincides with at least a part of the side surface of the metal bonding layer on the side opposite to the center of the substrate.

[0015] In the above configuration, the functional element can be an elastic wave element.

[0016] The present invention is a filter including the above-described electronic component.

[0017] The present invention is a multiplexer including the above-described filter.

[0018] The present invention is a method for manufacturing an electronic component, including a step of sealing a plurality of functional elements in a void with a plurality of annular metal layers and a lid by joining, via a metal bonding layer, a first surface of a plurality of annular metal layers provided on a substrate so as to surround the plurality of functional elements provided on the substrate in a plan view, and a second surface of one lid facing the plurality of annular metal layers, on at least the center side of a convex portion provided on the first surface or the second surface and extending in a direction in which the plurality of annular metal layers extend in a plan view; and a step of cutting the substrate and the lid between the plurality of annular metal layers.

Advantages of the Invention

[0019] According to the present invention, it is possible to suppress a shortage of the metal bonding layer between the annular metal layer and the lid.

Brief Description of the Drawings

[0020] [Figure 1] FIG. 1(a) and FIG. 1(b) are a cross-sectional view and a plan view of an elastic wave device according to Example 1. [Figure 2] FIG. 2 is a plan view of an elastic wave element in Example 1. [Figure 3] FIG. 3 is a plan view showing a manufacturing method of an elastic wave device in Example 1. [Figure 4] FIGS. 4(a) to 4(c) are cross-sectional views showing a manufacturing method of an elastic wave device in Example 1. [Figure 5] FIGS. 5(a) and 5(b) are cross-sectional views showing a manufacturing method of an elastic wave device in Comparative Example 1. [Figure 6] FIGS. 6(a) and 6(b) are cross-sectional views showing a manufacturing method of an elastic wave device in Example 1. [Figure 7] FIGS. 7(a) to 7(c) are enlarged views of the vicinity of an annular metal layer of an elastic wave device in Modifications 1 to 3 of Example 1. [Figure 8] FIGS. 8(a) to 8(c) are enlarged views of the vicinity of an annular metal layer of an elastic wave device in Modifications 4 to 6 of Example 1. [Figure 9] FIG. 9 is a plan view showing a manufacturing method of an elastic wave device in Modification 7 of Example 1. [Figure 10] FIGS. 10(a) and 10(b) are plan views showing manufacturing methods of elastic wave devices in Modifications 8 and 9 of Example 1, respectively. [Figure 11] FIGS. 11(a) to 11(c) are cross-sectional views showing a manufacturing method of an elastic wave device according to Modification 10 of Example 1. [Figure 12] FIGS. 12(a) to 12(c) are cross-sectional views showing a manufacturing method of an elastic wave device according to Modification 10 of Example 1. [Figure 13] FIGS. 13(a) and 13(b) are cross-sectional views showing a manufacturing method of an elastic wave device according to Modification 10 of Example 1. [Figure 14]Figures 14(a) to 14(d) are cross-sectional views showing a method for manufacturing an elastic wave device according to a modified example 11 of Example 1. [Figure 15] Figures 15(a) and 15(b) are cross-sectional views showing a method for manufacturing an elastic wave device according to a modified example 11 of Example 1. [Figure 16] Figures 16(a) and 16(b) are cross-sectional views showing a method for manufacturing an elastic wave device according to a modified example 12 of Example 1. [Figure 17] Figures 17(a) and 17(b) are cross-sectional views showing a method for manufacturing an elastic wave device according to a modified example 12 of Example 1. [Figure 18] Figure 18(a) is a cross-sectional view of the elastic wave device according to modified example 13 of Example 1, and Figure 18(b) is a cross-sectional view of the elastic wave element in modified example 13 of Example 1. [Figure 19] Figure 19(a) is a circuit diagram of the filter according to Example 2, and Figure 19(b) is a circuit diagram of the duplexer according to Modification 1 of Example 2. [Modes for carrying out the invention]

[0021] The embodiments of the present invention will be described below with reference to the drawings. [Examples]

[0022] Example 1 is an example of an elastic wave device having an elastic wave element as an electronic component. Figures 1(a) and 1(b) are a cross-sectional view and a plan view of the elastic wave device according to Example 1. Figure 1(b) mainly shows the substrate 10, the annular metal layer 30, and the protrusion 34. The thickness direction of the substrate 10 is the Z direction, and the planar directions of the substrate 10 are the X and Y directions.

[0023] As shown in Figures 1(a) and 1(b), the substrate 10 comprises a support substrate 10a, a piezoelectric layer 10c provided on the support substrate 10a, and an insulating layer 10b provided between the support substrate 10a and the piezoelectric layer 10c. A functional element, an elastic wave element 12, and a metal layer 14 are provided on the piezoelectric layer 10c. The elastic wave element 12 is, for example, a surface acoustic wave element. The metal layer 14 functions as wiring and pads electrically connected to the elastic wave element 12. The piezoelectric layer 10c and the insulating layer 10b are removed in the peripheral area of ​​the substrate 10 and in the region where the via wiring 16 is provided on the substrate 10, and the upper surface of the substrate 10 is the upper surface of the support substrate 10a. The via wiring 16 penetrates the support substrate 10a. A terminal 18 is provided on the lower surface of the substrate 10. The via wiring 16 electrically connects the metal layer 14 and the terminal 18. An annular metal layer 30 is provided on a support substrate 10a at the periphery of the substrate 10, surrounding the elastic wave element 12. A protrusion 34 is provided on the annular metal layer 30. The width of the protrusion 34 is narrower than the width of the annular metal layer 30. A lid 20 is provided above the substrate 10. A metal layer 22 is provided on the lower surface of the lid 20. The annular metal layer 30 and the metal layer 22 are joined by a bonding layer 24. The lid 20 and the annular metal layer 30 seal the elastic wave element 12 in the gap 26.

[0024] The planar shape of the substrate 10 is approximately rectangular. The planar shape of the annular metal layer 30 is also approximately rectangular and extends along the outer circumference of the substrate 10. The planar shape of the protrusion 34 is also approximately rectangular and is provided in an annular shape on the upper surface of the annular metal layer 30. The planar shapes of the annular metal layer 30 and the protrusion 34 are rounded rectangles with rounded corners.

[0025] The support substrate 10a is, for example, a sapphire substrate, alumina substrate, quartz substrate, crystal substrate, spinel substrate, SiC substrate, or silicon substrate. The insulating layer 10b is, for example, a single layer or a stack of silicon oxide layer, aluminum oxide layer, silicon nitride layer, or aluminum nitride layer. 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 crystal substrate. The single-crystal lithium tantalate substrate and the single-crystal lithium niobate substrate are, for example, rotational Y-cut X-propagation substrates. The metal layer 14, via wiring 16, and terminals 18 are, for example, a single layer or a stack of metal layers such as a copper layer, gold layer, silver layer, titanium layer, nickel layer, or tungsten layer. The lid 20 is, for example, a metal layer such as Kovar, or an insulating layer such as a sapphire substrate, alumina substrate, quartz substrate, crystal substrate, spinel substrate, SiC substrate, or 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 gap 26.

[0026] The metal layer 22 is provided when the bonding layer 24 and the lid 20 cannot be directly joined, and is a layer that provides good wettability to the bonding layer 24. If the bonding layer 24 is gold-tin, the metal layer 22 is, for example, a gold layer. If the bonding layer 24 and the lid 20 can be directly joined, the metal layer 22 may not be provided. The bonding layer 24 is, for example, gold-tin solder, tin-silver solder, or tin-silver-copper solder. The annular metal layer 30 functions as a shield, so it is preferable to use a material with low resistivity, such as a copper layer or a gold layer. The protrusions 34 may be made of the same material as the annular metal layer 30, or a different material. The protrusions 34 are, for example, metal layers such as a copper layer, gold layer, nickel layer, titanium layer, or Kovar layer. The protrusions 34 may also be an insulating layer such as resin.

[0027] Figure 2 is a plan view of the elastic wave element in Embodiment 1. As shown in Figure 2, the elastic 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 electrodes 40a have a plurality of electrode fingers 40b and a busbar 40c connecting the plurality of electrode fingers 40b. The reflector 42 is 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 from, for example, an aluminum film, a copper film, or a molybdenum film. A protective film or 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. For this reason, the elastic wave element 12 is covered with an air gap 26 so as not to restrict the elastic waves.

[0028] [Manufacturing method of Example 1] Figure 3 is a plan view showing the manufacturing method of the elastic wave device in Example 1, and is a plan view of the substrate 10 before the lid 20 is bonded to the annular metal layer 30. Figures 4(a) to 4(c) are cross-sectional views showing the manufacturing method of the elastic wave device in Example 1, and correspond to cross-section AA in Figure 3. As shown in Figure 3, the substrate 10 has a plurality of regions 36 arranged in a matrix. Regions 36 are regions that will become elastic wave devices. The dashed lines are cutting lines 38. The annular metal layers 30 provided in adjacent regions 36 are provided adjacent to each other via the cutting lines 38.

[0029] As shown in Figure 4(a), an annular metal layer 30 and a protrusion 34 are provided in the region of the substrate 10 from which the piezoelectric layer 10c and insulating layer 10b have been removed, and a bonding material 23 is provided on the annular metal layer 30 and the protrusion 34. A lid 20 is placed on the substrate 10. A metal layer 22 is provided on the lower surface of the lid 20. When the annular metal layer 30 is formed using the electroplating method, the sides of the annular metal layer 30 may be inclined. Also, the upper surface of the annular metal layer 30 may be curved with the central part protruding upward.

[0030] As shown in Figure 4(b), the substrate 10 is heated so that the bonding material 23 reaches a temperature above its melting point. When the bonding material 23 is gold-tin (with a tin composition of 20% by mass), the melting point of gold-tin is approximately 270°C. Therefore, the temperature of the bonding material 23 is heated to, for example, approximately 300°C. The lid 20 is pressed against the bonding material 23 from above. The bonding material 23 is bonded to the metal layer 22. After that, by returning the substrate 10 to room temperature, the bonding material 23 solidifies, and the lid 20 is bonded to the annular metal layer 30 via the bonded layer 24 formed by the solidified bonding material 23. When the bonded layer 24 is gold-tin, the bonded layer 24 becomes a eutectic of gold and tin. In addition, the gold in the metal layer 22 and the gold-tin in the bonding material 23 may become one to form the gold-tin of the bonded layer 24.

[0031] As shown in Figure 4(c), the lid 20 and substrate 10 are cut along the cutting line 38. Laser dicing or blade dicing is used for cutting. This completes the fabrication of the elastic wave device in Example 1.

[0032] [Comparative Example 1] Figures 5(a) and 5(b) are cross-sectional views showing the manufacturing method of the elastic wave device in Comparative Example 1. As shown in Figure 5(a), in Comparative Example 1, no protrusions are provided on the annular metal layer 30. Similar to Figure 4(b) of Example 1, the lid 20 is joined to the annular metal layer 30 via a bonding material 23. At this time, the molten bonding material 23, such as gold-tin solder, tends to accumulate in areas of the annular metal layer 30 with a large surface area due to surface tension. For example, in Figure 3, the molten bonding material 23 tends to accumulate at the point 55 where the corners of the four annular metal layers 30 meet. As indicated by the arrow 50 in Figure 5(a), the bonding material 23 moves between adjacent annular metal layers 30, and there is a shortage of bonding material 23 in the area 52 between the annular metal layer 30 on the +X side and the lid 20.

[0033] As shown in Figure 5(b), after the molten bonding material 23 solidifies and the bonding layer 24 is formed, the lid 20, bonding layer 24, and substrate 10 are cut along the cutting line 38. In range 52, the bonding layer 24 is not provided between the annular metal layer 30 and the lid 20. As a result, the airtightness of the void 26 deteriorates.

[0034] [Example 1] Figures 6(a) and 6(b) are cross-sectional views showing the method for manufacturing an elastic wave device in Example 1. As shown in Figure 6(a), in Example 1, even if the bonding material 23 attempts to move between adjacent annular metal layers 30 as indicated by arrow 50, the bonding material 23 at location 54 on the central side of the substrate 10 relative to the protrusion 34 does not move between the annular metal layers 30 because the protrusion 34 acts as a dam.

[0035] As shown in Figure 6(b), after the molten bonding material 23 solidifies and the bonding layer 24 is formed, the lid 20, the bonding layer 24, and the substrate 10 are cut along the cutting line 38. At location 54, the bonding layer 24 is provided between the annular metal layer 30 and the lid 20. This ensures that the airtightness of the gap 26 is maintained. The side surface 39a of the lid 20 and the side surface 39b of the bonding layer 24 are approximately coincident.

[0036] [Example 1 Modification 1] Figures 7(a) to 8(c) are enlarged views of the vicinity of the annular metal layer of the elastic wave device in modified examples 1 to 6 of Example 1. As shown in Figure 7(a), in modified example 1 of Example 1, the protrusion 34 is located outside the center line 58 of the annular metal layer 30 (on the -X side, opposite the center of the substrate 10). The other configurations are the same as in Example 1 and will not be described.

[0037] [Modification 2 of Example 1] As shown in Figure 7(b), in the modified example 2 of Example 1, the protrusion 34 is located inside the center line 58 of the annular metal layer 30 (on the +X side, towards the center of the substrate 10). The other configurations are the same as in Example 1 and will not be described.

[0038] As shown in Modifications 1 and 2 of Example 1, the protrusion 34 may be provided either outside or inside the center line 58 of the annular metal layer 30. In Modification 2 of Example 1, as shown in Figure 6(b), if the bonding layer 24 outside the protrusion 34 is insufficient, the planar area of ​​the bonding layer 24 inside the protrusion 34 becomes smaller. For this reason, it is preferable that the protrusion 34 overlaps with the center line 58 of the annular metal layer 30 or is located outside the center line 58.

[0039] [Modification 3 of Example 1] As shown in Figure 7(c), in Modification 3 of Example 1, multiple protrusions 34 are provided in the width direction of the annular metal layer 30. The other configurations are the same as in Example 1 and will not be described. As in Modification 3 of Example 1, multiple protrusions 34 may be provided in the direction in which the annular metal layer 30 extends (the direction intersecting the Y direction in Figure 7(c)). This further suppresses the movement of the bonding material 23 between the annular metal layer 30 and the lid 20.

[0040] [Modification 4 of Example 1] As shown in Figure 8(a), in Modification 4 of Example 1, the thickness T2 of the protrusion 34 is smaller than the thickness T1 between the annular metal layer 30 and the metal layer 22. A bonding layer 24 with a thickness T3 is provided between the protrusion 34 and the metal layer 22. The other configurations are the same as in Example 1 and will not be described.

[0041] [Modification 5 of Example 1] As shown in Figure 8(b), in Modification 5 of Example 1, the protrusion 34 is provided on the lower surface of the lid 20. The thickness T2 of the protrusion 34 is smaller than the thickness T1 between the annular metal layer 30 and the metal layer 22. A bonding layer 24 with a thickness T3 is provided between the protrusion 34 and the annular metal layer 30. The other configurations are the same as in Example 1 and will not be described. As in Modification 5 of Example 1, the protrusion 34 may be provided on the lower surface of the lid 20.

[0042] As shown in Modifications 4 and 5 of Example 1, a bonding layer 24 may be provided between the protrusion 34 and the lid 20 or between the protrusion 34 and the annular metal layer 30. If the thickness T3 of the bonding layer 24 between the protrusion 34 and the lid 20 or the annular metal layer 30 is large, the dam effect of the protrusion 34 in suppressing the movement of the bonding material 23 will be reduced. From this viewpoint, the thickness T3 is preferably less than or equal to the thickness T2 of the protrusion 34, more preferably less than or equal to 1 / 2 times the thickness T2, and even more preferably less than or equal to 1 / 5 times the thickness T2. As shown in Figure 4(c), a bonding layer 24 may not be provided between the protrusion 34 and the lid 20 or between the protrusion 34 and the annular metal layer 30. The thickness T1 between the annular metal layer 30 and the lid 20 is, for example, 1 μm to 5 μm, and the thickness T2 of the protrusion 34 is, for example, 0.5 μm to 5 μm.

[0043] [Modification 6 of Example 1] As shown in Figure 8(c), in Modification 6 of Example 1, the annular metal layer 30 comprises an annular metal layer 30a provided on the substrate 10 and an annular metal layer 30b provided on the annular metal layer 30a. The annular metal layer 30a functions as a shield, so it is preferable to use a material with low resistivity, such as a copper layer, gold layer, aluminum layer, or silver layer. The annular metal layer 30b functions as a diffusion prevention layer to prevent the diffusion of elements between the bonding layer 24 and the annular metal layer 30a, and is such as a nickel layer, titanium layer, or chromium layer. The other components are the same as in Example 1 and will not be described. Modifications 1 to 5 of Example 1 may also include annular metal layers 30a and 30b.

[0044] In Figures 4(c), 7(a) to 8(c) of Example 1 and its modified examples 1 to 6, the width W1 (e.g., maximum width) of the annular metal layer 30 in the X direction is, for example, 10 μm to 30 μm. The width W2 (e.g., maximum width) of the protrusion 34 in the X direction is, for example, 1 μm to 15 μm. The thickness (e.g., maximum thickness) of the annular metal layer 30 is, for example, 10 μm to 30 μm. The thickness (e.g., maximum thickness) of the annular metal layer 30b in Figure 8(c) is, for example, 1 μm to 5 μm. The thickness of the support substrate 10a is, for example, 50 μm to 200 μm, and the thickness of the lid 20 is, for example, 10 μm to 50 μm.

[0045] From the viewpoint of increasing the bonding strength between the annular metal layer 30 and the lid 20 in areas other than the protrusion 34, the width W2 of the protrusion 34 in the X direction (the direction intersecting the direction in which the annular metal layer 30 extends) is preferably 1 / 2 or less, more preferably 1 / 3 or less, and even more preferably 1 / 5 or less, of the width W1 of the annular metal layer 30 in the X direction. From the viewpoint of ensuring the strength of the protrusion 34, the width W2 is preferably 1 / 10 or more of the width W1.

[0046] [Example 1 Modification 7] Figure 9 is a plan view showing a method for manufacturing an elastic wave device in a modified example 7 of Example 1. As shown in Figure 9, the bonding material 23 tends to accumulate at the points 55 where the corners of the annular metal layer 30 meet. Therefore, protrusions 34 are provided at the roughly rectangular corners 57 of the annular metal layer 30. The bonding between the annular metal layer 30 and the lid 20 becomes weaker at the points where the protrusions 34 are provided. Therefore, protrusions 34 are not provided in the central parts of the roughly rectangular sides of the annular metal layer 30. This suppresses the deficiency of the bonding layer 24 between the annular metal layer 30 and the lid 20 at the roughly rectangular corners 57 of the annular metal layer 30, and strengthens the bonding between the annular metal layer 30 and the lid 20 in the central parts of the roughly rectangular sides of the annular metal layer 30. The other configurations are the same as in Example 1 and will not be described further.

[0047] [Modification 8 of Example 1] Figure 10(a) is a plan view showing a method for manufacturing an elastic wave device in a modified example 8 of Example 1. As shown in Figure 10(a), a wide portion 32b may be provided in the annular metal layer 30. The width W3 of the wide portion 32b is wider than the width W1 of the portion 32a of the annular metal layer 30 other than the wide portion 32b. As a result, the bonding material 23 tends to accumulate in the wide portion 32b, and there is a possibility that the bonding material 23 will be insufficient in the range 56 of the annular metal layer 30 adjacent to the wide portion 32b. Therefore, a protrusion 34 is provided in the annular metal layer 30 adjacent to the range 56. This suppresses the shortage of bonding layer 24 in the range 56. The protrusion 34 is not provided in at least a part of the portion 32a of the annular metal layer 30 other than the wide portion 32b. This strengthens the bond between the annular metal layer 30 and the lid 20 in the portion 32a. The other configurations are the same as in Example 1 and are omitted from the explanation.

[0048] [Modification 9 of Example 1] Figure 10(b) is a plan view showing a method for manufacturing an elastic wave device in a modified example 9 of Example 1. As shown in Figure 10(b), a protrusion 34 may be provided in a range 56 of the annular metal layer 30 adjacent to the wide portion 32b. This suppresses a shortage of bonding material 23 on the -X side of the protrusion 34 within range 56, and strengthens the bond between the annular metal layer 30 and the lid 20 in the annular metal layer 30 outside of range 56. The other configurations are the same as in Example 1 and will not be described. A protrusion 34 may be provided in the annular metal layer 30 adjacent to range 56, and a protrusion 34 may also be provided in the range 56 of the annular metal layer 30.

[0049] [Example 10: Modified Version] Modifications 10 to 12 of Example 1 are examples of methods for forming the protrusions 34. Figures 11(a) to 13(b) are cross-sectional views showing a method for manufacturing an elastic wave device according to modification 10 of Example 1. As shown in Figure 11(a), a substrate 10 is prepared in which a support substrate 10a, an insulating layer 10b, and a piezoelectric layer 10c are laminated. The support substrate 10a, insulating layer 10b, and piezoelectric layer 10c are, for example, a sapphire substrate, an aluminum oxide layer, and a lithium tantalate layer, respectively.

[0050] As shown in Figure 11(b), a mask layer 60 having an opening 61 is formed on the substrate 10. The mask layer 60 is, for example, a photoresist. Using the mask layer 60 as a mask, the piezoelectric layer 10c and the upper part of the insulating layer 10b are etched. This forms a recess 53a in the insulating layer 10b.

[0051] As shown in Figure 11(c), the mask layer 60 is removed. Then, a mask layer 62 having an opening 63 that overlaps the recess 53a is formed on the substrate 10. The insulating layer 10b is etched using the mask layer 62 as a mask. This forms a protrusion 35 from the insulating layer 10b. An opening 53 is formed from the recess 53a other than the protrusion 35, penetrating the piezoelectric layer 10c and the insulating layer 10b.

[0052] As shown in Figure 12(a), a seed layer 31 is formed on the substrate 10 so as to cover the insulating layer 10b, the piezoelectric layer 10c, and the protrusions 35. The seed layer 31 is, for example, a titanium layer and a copper layer from the substrate 10 side. As shown in Figure 12(b), a mask layer 64 having an opening 65 is formed on the seed layer 31. The opening 65 is formed within the opening 53. The mask layer 64 is, for example, a photoresist layer. An annular metal layer 30a, an annular metal layer 30b, and a bonding material 23 are formed within the opening 65 using an electroplating method. A protrusion 34 corresponding to the protrusions 35 is formed on the upper surface of the annular metal layer 30. The annular metal layers 30a, 30b, and bonding material 23 are, for example, a copper layer, a nickel layer, and a gold-tin layer, respectively. As shown in Figure 12(c), the mask layer 64 is removed. The seed layer 31 is removed using the annular metal layer 30 and the bonding material 23 as a mask. From here on, the illustration of the seed layer 31 between the annular metal layer 30 and the support substrate 10a is omitted.

[0053] As shown in Figure 13(a), similar to Figure 4(b), the lid 20 is joined to the annular metal layer 30 via the bonding layer 24 formed by the solidified bonding material 23. The lid 20 is, for example, a Kovar plate. As shown in Figure 13(b), similar to Figure 4(c), the lid 20 and the substrate 10 are cut along the cutting line 38. This completes the formation of the elastic wave device in the modified example 10 of Example 1. As in the modified example 10 of Example 1, the protrusion 34 may be part of the annular metal layer 30.

[0054] [Example 11: Modified Version] Figures 14(a) to 15(b) are cross-sectional views showing a method for manufacturing an elastic wave device according to a modified example 11 of Example 1. As shown in Figure 14(a), a protrusion 34 is formed on the lid 20 (-Z side). The protrusion 34 is formed, for example, by a plating method. The lid 20 is, for example, a Kovar plate, and the protrusion 34 is, for example, a nickel layer. As shown in Figure 14(b), a metal layer 22 is formed on the lid 20 so as to cover the protrusion 34. The metal layer 22 is, for example, a nickel layer and a gold layer from the lid 20 side.

[0055] As shown in Figure 14(c), a mask layer 60 having an opening 61 is formed on the piezoelectric layer 10c of Figure 11(a). The piezoelectric layer 10c and the insulating layer 10b are etched using the mask layer 60 as a mask. This forms an opening 53 that penetrates the piezoelectric layer 10c and the insulating layer 10b. As shown in Figure 14(d), a seed layer 31 is formed on the substrate 10 so as to cover the insulating layer 10b and the piezoelectric layer 10c, similar to Figure 12(a). A mask layer 64 having an opening 65 is formed, similar to Figure 12(b). The opening 65 is formed within the opening 53. An annular metal layer 30 and a bonding material 23 are formed within the opening 65, for example, using an electroplating method similar to that in Figure 12(b). No protrusions are formed on the upper surface of the annular metal layer 30.

[0056] As shown in Figure 15(a), the mask layer 64 is removed and the seed layer 31 is etched, similar to Figure 12(c). Hereafter, the seed layer 31 between the annular metal layer 30 and the support substrate 10a will not be shown. Similar to Figure 4(b), the lid 20 is joined to the annular metal layer 30 via the bonding layer 24 in which the bonding material 23 has solidified. As shown in Figure 15(b), the lid 20 and the substrate 10 are cut along the cutting line 38, similar to Figure 4(c). This completes the formation of the elastic wave device in Modification 11 of Example 1. As in Modification 11 of Example 1, the convex portion 34 may be formed on the lid 20.

[0057] [Modification 12 of Example 1] Figures 16(a) to 17(b) are cross-sectional views showing a method for manufacturing an elastic wave device according to a modified example 12 of Example 1. As shown in Figure 16(a), a mask layer 64 having an opening 65 is formed on a seed layer 31, similar to Figure 14(d). An annular metal layer 30 and a bonding material 23 are formed within the opening 65 using electroplating. The bonding material 23 is not formed on the annular metal layer 30.

[0058] As shown in Figure 16(b), the mask layer 64 is removed. A mask layer 66 having an opening 67 is formed. The opening 67 is provided on a part of the upper surface of the annular metal layer 30. The mask layer 66 is, for example, a photoresist. A protrusion 34 is formed in the opening 67 using an electroplating method. The protrusion 34 is, for example, a nickel layer.

[0059] As shown in Figure 17(a), the mask layer 66 is removed. A mask layer 68 having an opening 69 is formed. The opening 69 is formed to substantially coincide with the annular metal layer 30. The mask layer 68 is, for example, a photoresist. A bonding material 23 is formed on the annular metal layer 30 and the protrusion 34 within the opening 69 using an electroplating method.

[0060] As shown in Figure 17(b), the mask layer 68 is removed. The seed layer 31 is removed using the annular metal layer 30 and the bonding material 23 as a mask. The seed layer 31 between the annular metal layer 30 and the support substrate 10a is not shown. Subsequently, the elastic wave device in modified example 12 of Example 1 is formed by performing the same steps as in Figures 4(b) and 4(c). As in modified example 12 of Example 1, the convex portion 34 may be formed on the annular metal layer 30.

[0061] [Example 13: Modified Example] Figure 18(a) is a cross-sectional view of an elastic wave device according to a modified example 13 of Example 1. As shown in Figure 18(a), an elastic 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 Figure 1(a) of Example 1.

[0062] Figure 18(b) is a cross-sectional view of the elastic wave element in modified example 13 of Embodiment 1. As shown in Figure 18(b), in the elastic 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. A gap 45 is formed between the lower electrode 44 and the substrate 10. The 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 the resonance region 47. In the resonance region 47, the lower electrode 44 and the upper electrode 48 excite elastic waves in the thickness longitudinal vibration mode or thickness shear vibration mode within the piezoelectric film 46. The lower electrode 44 and the upper electrode 48 are 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 gap 45, an acoustic reflective film that reflects elastic waves may be provided. The other configurations are the same as in Embodiment 1 and will not be described. As shown in Modification 13 of Example 1, in Example 1 and its Modifications 1 to 12, the elastic wave element may be a piezoelectric thin-film resonator.

[0063] In Example 1 and its modified form, as shown in Figure 3, in a plan view, the multiple annular metal layers 30 are arranged to surround each of the multiple elastic wave elements 12 (see Figure 1(a)) provided on the substrate 10. The protrusions 34 are provided on the upper surface (first surface) of the annular metal layer 30 opposite the substrate 10, or on the lower surface (second surface) of one lid 20 facing the annular metal layer 30, and extend in the direction in which the annular metal layer 30 extends in a plan view. As shown in Figures 4(a) and 4(b), the upper surface of the annular metal layer 30 and the lower surface of one lid 20 are joined via a bonding layer 24 (metal bonding layer) at least on the center side of the substrate 10 of the protrusions 34. In this way, the multiple annular metal layers 30 and the lid 20 seal the multiple elastic wave elements 12 in the gap 26. As shown in Figure 4(c), the substrate 10 and the lid 20 are cut between the multiple annular metal layers 30. As a result, as shown in Figure 6(a), even if the bonding material 23 between the annular metal layer 30 and the lid 20 moves between the annular metal layer 30, the bonding material 23 between the annular metal layer 30 and the lid 20 at the central part 54 of the protrusion 34 on the substrate 10 does not move. Therefore, a shortage of bonding layer 24 between the annular metal layer 30 and the lid 20 can be suppressed.

[0064] As shown in Figures 9 to 10(b) of Modifications 7 to 9 of Example 1, the protrusions 34 are provided in a portion of the region where the annular metal layer 30 surrounds the elastic wave element 12. This suppresses the deficiency of the bonding layer 24 by providing the protrusions 34 in a portion of the region where a deficiency of the bonding layer 24 is a problem. In the region where the protrusions 34 are provided, the bonding between the annular metal layer 30 and the lid 20 becomes weaker. Therefore, by not providing the protrusions 34 in the remaining region where a deficiency of the bonding layer 24 is not a problem, the bonding between the annular metal layer 30 and the lid 20 can be strengthened.

[0065] As shown at location 55 in Figure 9 of Modification 7 of Example 1, the bonding material 23 tends to accumulate at location 55 where the corners of the annular metal layer 30 meet. Therefore, a protrusion 34 is provided at a location corresponding to the corner of the substrate 10. This suppresses a shortage of bonding layer 24 at the corner 37 of the annular metal layer 30.

[0066] As shown in Figure 10(a), the annular metal layer 30 comprises a portion 32a (first portion) and a wider portion 32b (second portion) which is wider in the Y direction (a direction perpendicular to the direction in which the annular metal layer 30 extends) than portion 32a. The protrusion 34 is provided on the wider portion 32b. This makes it possible to suppress the deficiency of the bonding layer 24 in the annular metal layer 30 adjacent to the wider portion 32b.

[0067] After the substrate 10 in Figure 10(b) has been cut, the planar shape of the annular metal layer 30 is a substantially rectangular shape provided along the outer circumference of the substrate 10. The annular metal layer 30 comprises a portion 32a and a wide portion 32b provided on the first side 37a of the substantially rectangular shape. The convex portion 34 is provided on the portion 32c (third portion) of the second side 37b of the substantially rectangular shape, which is opposite the first side 37a and corresponds to the wide portion 32b. That is, the wide portion 32b and portion 32c are symmetrical with respect to a straight line 37d that passes through the center 37c of the substrate 10 and is parallel to the first side 37a and the second side 37b. This prevents a shortage of bonding layer 24 in the annular metal layer 30 adjacent to the wide portion 32b. Note that the rectangle does not have to be a geometric rectangle or square. The rectangle (substantially rectangular) includes a rounded rectangle with rounded corners and a rectangle where the angle between opposite sides is ±10° or less. In Figures 10(a) and 10(b), if the width W3 is, for example, 1.2 times or more, or 1.5 times or more, the bonding layer 24 tends to be insufficient. Therefore, it is preferable to provide the protrusions 34.

[0068] As shown in Figure 6(a), when the bonding material 23 moves between adjacent annular metal layers 30, at least a portion of the bonding layer 24 is not provided between the annular metal layer 30 and the lid 20 on the opposite side of the center of the substrate 10 of the protrusion 34. As shown in Figure 6(b), when the lid 20 is cut, the side surface 39a of the lid 20 and at least a portion of the outer side surface 39b of the bonding layer 24 coincide to the extent of manufacturing tolerance. In such cases, providing the protrusion 34 can suppress the shortage of bonding layer 24 at location 54.

[0069] The bonding layer 24 is, for example, solder. The melting point of the bonding layer 24 is lower than that of the annular metal layer 30. For example, the melting point of gold-tin (tin concentration is 20% by mass) is approximately 270°C. Thus, the melting point of solder is 300°C or lower. In contrast, the melting points of copper, nickel, gold, aluminum, and silver used in the annular metal layer 30 are 1085°C, 1455°C, 1064°C, 660°C, and 962°C, respectively, which are more than 300°C higher than the melting point of the bonding layer 24.

[0070] The resistivity of copper, gold, aluminum, and silver used in the annular metal layer 30a is 1.68 × 10⁻⁶, respectively. -8 Ω·m, 2.44 × 10 -8 Ω·m, 2.65 × 10 -8 Ω·m and 1.59 × 10 -8 The resistivity is Ω·m. The resistivity of nickel, titanium, and chromium used in the annular metal layer 30b is 7.0 × 10⁻⁶, respectively. -8 Ω·m, 4.2 × 10 -7 Ω·m and 1.3 × 10 -7 The resistivity is Ω·m. Thus, the resistivity of the annular metal layer 30b is more than twice and more than three times the resistivity of the annular metal layer 30a. Also, the thickness of the annular metal layer 30b is less than or equal to half the thickness of the annular metal layer 30a and less than or equal to one-fifth the thickness of the annular metal layer 30a.

[0071] In Example 1 and its modifications, examples of elastic wave elements 12 and 12a (surface acoustic wave resonators or piezoelectric thin-film resonators) were described as functional elements. However, the functional elements may also be passive elements such as inductors or capacitors, active elements including transistors, or MEMS (Micro Electro Mechanical Systems) elements. [Examples]

[0072] Figure 19(a) is a circuit diagram of the filter according to Embodiment 2. As shown in Figure 19(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. Elastic wave elements 12 and 12a of Embodiment 1 and its modified versions 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 and parallel resonators can be set as appropriate. A ladder filter has been described as an example of a filter, but a multimode filter may also be used.

[0073] Figure 19(b) is a circuit diagram of a duplexer according to Modification 1 of Example 2. As shown in Figure 19(b), a transmit filter 70 is connected between the common terminal Ant and the transmit terminal Tx. A receive filter 72 is connected between the common terminal Ant and the receive terminal Rx. The transmit filter 70 allows the transmit band signal from the high-frequency signal input from the transmit terminal Tx to pass to the common terminal Ant as the transmit signal, and suppresses signals of other frequencies. The receive filter 72 allows the receive band signal from the high-frequency signal input from the common terminal Ant to pass to the receive terminal Rx as the receive signal, and suppresses signals of other frequencies. At least one of the transmit filter 70 and the receive filter 72 can be the filter of Example 2.

[0074] I used Duplexa as an example of a multiplexer, but Triplexa or Quadplexa would also work.

[0075] Although 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 changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of symbols]

[0076] 10 circuit boards 10a support board 10b Insulating layer 10c piezoelectric layer 12, 12a Elastic wave element 14, 22 metal layer 16 via wiring 18 terminals 20 Lid 23 Bonding material 24 Bonding layer 26 void 30 Annular metal layer 32a, 32c part 32b Wide section 37 Corner 70 Sending Filter 72 Receiving Filter

Claims

1. circuit board and A functional element provided on the substrate, An annular metal layer is provided on the substrate so as to surround the functional element in a plan view, A lid provided on the annular metal layer, which seals the functional element within the gap with the annular metal layer, A convex portion is provided on the first surface of the annular metal layer facing the lid or on the second surface of the lid facing the annular metal layer, and extends in the direction in which the annular metal layer extends when viewed in plan, At least on the central side of the protruding portion of the substrate, a metal bonding layer is provided to join the first surface and the second surface, Equipped with, The aforementioned protrusion is provided in a portion of the region where the first surface and the second surface face each other, in the direction of extension, and not in the remaining portion of the direction of extension. The annular metal layer comprises a first portion and a second portion that is wider than the first portion in a direction perpendicular to the direction of extension. The aforementioned protrusion is an electronic component provided in the second portion of the region.

2. circuit board and A functional element provided on the substrate, An annular metal layer is provided on the substrate so as to surround the functional element in a plan view, A lid provided on the annular metal layer, which seals the functional element within the gap with the annular metal layer, A convex portion is provided on the first surface of the annular metal layer facing the lid or on the second surface of the lid facing the annular metal layer, and extends in the direction in which the annular metal layer extends when viewed in plan, At least on the central side of the protruding portion of the substrate, a metal bonding layer is provided to join the first surface and the second surface, Equipped with, The aforementioned protrusion is provided in a portion of the region where the first surface and the second surface face each other, in the direction of extension, and not in the remaining portion of the direction of extension. The planar shape of the annular metal layer is substantially rectangular and is provided along the outer circumference of the substrate. The annular metal layer comprises a first portion provided on the first side of the substantially rectangular shape, and a second portion provided on the first side and wider in a direction perpendicular to the direction extending from the first portion. The aforementioned protrusion is an electronic component provided on a third portion of the second side of the substantially rectangular shape that is opposite the first side, corresponding to the second portion.

3. The electronic component according to claim 1 or 2, wherein the width of the protrusion in a direction perpendicular to the direction of extension is 1 / 2 or less of the width of the annular metal layer in the direction perpendicular to that direction.

4. The electronic component according to claim 1 or 2, wherein the thickness of the metal bonding layer between the annular metal layer or the lid and the protrusion is less than or equal to the height of the protrusion.

5. The electronic component according to claim 1 or 2, wherein the side surface of the lid substantially coincides with at least a portion of the side surface of the metal bonding layer opposite the center of the substrate.

6. The electronic component according to claim 1 or 2, wherein the functional element is an elastic wave element.

7. A filter comprising the electronic component described in claim 6.

8. A multiplexer comprising the filter described in claim 7.

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