Electronic component

Abstract

To provide an electronic component capable of preventing a reduction in airtightness in a gap.SOLUTION: An acoustic wave device 100 comprises: a support substrate 10; an acoustic wave element 30 which is provided on the support substrate 10; a metal frame body 40 which is provided on the support substrate 10 while surrounding the acoustic wave element 30 in plan view; a lid 60 which is provided on the frame body 40 so as to sandwich a gap 20 together with the support substrate 10; a solder bonding layer 44 which seals the acoustic wave element 30 inside the gap 20 by bonding the frame body 40 to the lid 60, and has a shape widened at the bottom with its width gradually increasing from the frame body 40 toward the lid 60 in cross-sectional view; a metal columnar body 50 which is provided between the support substrate 10 and the lid 60 inside the gap 20, and in which a height from the support substrate 10 is higher than that of the frame body 40; and a solder bonding layer 54 which bonds the columnar body 50 to the lid 60, and has a shape widened at the bottom with its width gradually increasing from the columnar body 50 toward the lid 60 in cross-sectional view.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electronic component.

Background Art

[0002] There is known an electronic component in which a lid is provided on a frame surrounding a functional element, and the functional element is sealed in a gap between the lid and a support substrate (for example, Patent Documents 1 to 4). In order to suppress the lid from bending even when pressure is applied to the lid, it is known to provide a columnar body between the support substrate and the lid in the gap (for example, Patent Document 5).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when a columnar body is provided between the support substrate and the lid, a bonding failure may occur between the frame and the lid, resulting in a decrease in the airtightness of the gap.

[0005] The present invention has been made in view of the above problems, and an object thereof is to suppress a decrease in the airtightness of the gap.

Means for Solving the Problems

[0006] The present invention relates to a substrate, a functional element provided on the substrate, a metal frame provided on the substrate so as to surround the functional element in plan view, a lid provided on the frame and sandwiching a gap with the substrate, and joining the frame and the lid to seal the functional element in the gap. In a cross-section in the thickness direction of the substrate a first solder joint layer having a flared shape whose width gradually increases from the frame toward the lid, a metal columnar body provided between the substrate and the lid in the gap and having a height higher than that of the frame from the substrate, and joining the columnar body and the lid. In a cross-section in the thickness direction of the substrate The electronic component includes a second solder joint layer having a flared shape whose width gradually increases from the columnar body toward the lid.

[0007] In the above configuration, at least one of the lid and the substrate may be configured to have a step such that the distance from the substrate directly below the columnar body to the lid directly above the columnar body is longer than the distance from the substrate directly below the frame to the lid directly above the frame.

[0008] In the above configuration, at least one of the lid and the substrate has a distance is from the substrate directly below the columnar body to the lid directly above the columnar body longer than with a step , and the total height of the step(s) possessed by at least one of the lid and the substrate is 0.5 times or more and 1.5 times or less the difference between the height of the columnar body and the height of the frame and can be configured.

[0009] In the above configuration, the total height of the steps of at least one of the lid and the substrate can be configured to be substantially the same as the difference between the height of the columnar body and the height of the frame.

[0010] In the above configuration, the lid can be configured to have a step having a height substantially the same as the difference between the height of the columnar body and the height of the frame.

[0011] In the above configuration, the substrate can be configured to have the step with substantially the same height as the difference between the height of the columnar body and the height of the frame body.

[0012] In the above configuration, the frame body and the columnar body are plating layers , the of the above columnar body maximum The width can be configured to be larger than the maximum width of the frame body.

[0013] In the above configuration, a via wiring provided on the substrate and positioned directly below the columnar body and electrically connected to the columnar body, and a wiring between the functional element and the columnar body and the via wiring provided over can be provided.

[0014] In the above configuration, the functional element can be configured to be an elastic wave element.

[0015] In the above configuration, a filter can be formed by the elastic wave element.

[0016] In the above configuration, a multiplexer can be formed by the filter.

Advantages of the Invention

[0017] According to the present invention, it is possible to suppress a decrease in airtightness of the gap.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, with reference to the drawings, embodiments of the present invention will be described by taking the case of a surface acoustic wave device as an example of an electronic component.

EXAMPLE

[0020] Fig. 1(a) is a plan view of the surface acoustic wave device 100 according to Example 1, and Fig. 1(b) is a cross-sectional view taken along line A-A of Fig. 1(a). Fig. 1(a) shows mainly the support substrate 10, the piezoelectric layer 12, the via wiring 16, the frame 40, and the columnar body 50 through the lid 60. In Fig. 1(a), for clarity of the drawing, the piezoelectric layer 12 and the frame 40 are hatched. As shown in Figs. 1(a) and 1(b), in the surface acoustic wave device 100, the piezoelectric layer 12 is bonded to the upper surface of the support substrate 10.

[0021] The support substrate 10 is, for example, a sapphire substrate, an alumina substrate, a spinel substrate, a quartz substrate, a quartz crystal substrate, or a silicon substrate, and its thickness is 50 μm to 300 μm. The sapphire substrate is a substrate mainly composed of single-crystalline Al2O3. The alumina substrate is a substrate mainly composed of polycrystalline Al2O3. The spinel substrate is a substrate mainly composed of single-crystalline or polycrystalline MgAl2O4. The quartz substrate is a substrate mainly composed of amorphous SiO2. The quartz crystal substrate is a substrate mainly composed of single-crystalline SiO2.

[0022] The piezoelectric layer 12 is, for example, a single-crystalline lithium tantalate layer or a single-crystalline lithium niobate layer, and its thickness is 0.5 μm to 30 μm. The thickness of the piezoelectric layer 12 is, for example, smaller than the wavelength of the elastic wave of the main mode excited by the elastic wave device 30. The linear expansion coefficient of the support substrate 10 is smaller than the linear expansion coefficient of the piezoelectric layer 12. Thereby, the frequency temperature coefficient of the elastic wave device 100 can be reduced. An insulating layer such as silicon oxide or aluminum nitride may be provided between the piezoelectric layer 12 and the support substrate 10. Thus, the piezoelectric layer 12 is directly or indirectly bonded to the support substrate 10.

[0023] One or more elastic wave devices 30 are provided on the upper surface of the piezoelectric layer 12. Terminals 14 are provided on the lower surface of the support substrate 10. The terminals 14 are foot pads for electrically connecting the elastic wave devices 30 to the outside. Via wirings 16 penetrating the support substrate 10 are provided. One end of the via wiring 16 is connected to the terminal 14. The other end of the via wiring 16 is connected to a wiring 18 extending from the upper surface of the piezoelectric layer 12 to the upper surface of the support substrate 10. Thereby, the elastic wave devices 30 are electrically connected to the terminals 14 via the wiring 18 and the via wiring 16. The terminals 14, the via wirings 16, and the wiring 18 are metal layers including, for example, a titanium layer, a copper layer, an aluminum layer, a platinum layer, a nickel layer, and / or a gold layer, etc. The terminals 14, the via wirings 16, and the wiring 18 may be a single-layer metal layer or a laminated metal layer in which a plurality of layers are laminated.

[0024] The piezoelectric layer 12 is not provided in the peripheral region of the support substrate 10. In plan view, a frame body 40 is provided on the support substrate 10 so as to surround the piezoelectric layer 12 and the surface acoustic wave device 30. The frame body 40 is provided on the support substrate 10 away from the piezoelectric layer 12. An annular solder joint layer 44 is provided on the annular frame body 40.

[0025] The frame body 40 is, for example, a laminated film of a seed layer (not shown), a metal layer 40a mainly composed of a first metal element, and a metal layer 40b mainly composed of a second metal element. The first metal element is, for example, copper or aluminum. The second metal element is, for example, nickel or platinum. The metal layers 40a and 40b are plating layers formed by an electrolytic plating method.

[0026] The metal layer 40a is thicker than the seed layer and the metal layer 40b, and is the thickest metal layer among the metal layers constituting the frame body 40. The thickness of the seed layer is, for example, 0.5 μm or less. The thickness of the metal layer 40a is about 15 μm to 25 μm, for example. The thickness of the metal layer 40b is about 2 μm to 5 μm. The maximum width of the metal layer 40a is about 20 μm to 25 μm, for example.

[0027] A lid 60 is provided on the frame body 40 so that a gap 20 is formed between the lid 60 and the support substrate 10. The lid 60 includes a metal layer 62 and a main body 64. The lid 60 is generally flat and rectangular in plan view. The upper surface of the lid 60 is flat. The lid 60 is joined to the frame body 40 by the metal layer 62 reacting with the solder joint layer 44 to form an alloy. The surface acoustic wave device 30 is sealed in the gap 20 by the lid 60, the frame body 40, and the solder joint layer 44. A part of the metal layer 62 of the lid 60 has reacted with the solder joint layer 44 to form an alloy layer. The solder joint layer 44 has a flare shape in which the width gradually increases from the frame body 40 toward the lid 60. Since the solder joint layer 44 has such a flare shape, the joining reliability between the frame body 40 and the lid 60 can be improved, and a decrease in airtightness in the gap 20 can be suppressed. The starting point of the flare shape of the solder joint layer 44 is the end of the frame body 40.

[0028] The main body 64 of the lid 60 is thicker than the metal layer 62 and is formed of a metal material harder than the metal layer 62 so that the lid 60 is difficult to be crushed. The metal layer 62 is a metal layer that joins with the solder joint layer 44 and a solder joint layer 54 to be described later, and is, for example, a laminated metal layer of a nickel layer and a gold layer. The main body 64 is a metal layer with a small coefficient of linear expansion, for example, a kovar layer, and its thickness is 20 μm to 100 μm. Note that the main body 64 may be a silicon layer or a sapphire layer.

[0029] The frame body 40 may be electrically connected to a ground terminal provided on the lower surface of the support substrate 10 via a via wiring that penetrates the support substrate 10. Since the frame body 40, the solder joint layer 44, and the lid 60 are made of metal, a shielding effect can be imparted to the frame body 40, the solder joint layer 44, and the lid 60 by supplying a ground potential. Further, since the frame body 40, the solder joint layer 44, and the lid 60 are made of metal, the elastic wave element 30 can be hermetically sealed in the gap 20. Note that the frame body 40, the solder joint layer 44, and the lid 60 are not electrically connected to the elastic wave element 30 on the support substrate 10.

[0030] The piezoelectric layer 12 has an opening 22 that penetrates from the upper surface to the lower surface near the center of the support substrate 10. In the opening 22, for example, the upper surface of the support substrate 10 is exposed. In the opening 22, a columnar body 50 is provided between the support substrate 10 and the lid 60. The columnar body 50 is located in the gap 20, is provided away from the piezoelectric layer 12, and is in contact with, for example, the upper surface of the support substrate 10. The height of the columnar body 50 measured from the support substrate 10 is higher than that of the frame body 40. A solder joint layer 54 is provided on the columnar body 50. The columnar body 50 is joined to the lid 60 by the metal layer 62 of the lid 60 reacting with the solder joint layer 54 to form an alloy.

[0031] By providing the columnar body 50 between the support substrate 10 and the lid 60, even when pressure is applied to the lid 60 from above, the deflection generated in the lid 60 can be suppressed. For this reason, it is possible to suppress the lid 60 from contacting the elastic wave element 30 or the like and deteriorating the characteristics.

[0032] The columnar body 50 is, for example, a laminated film including a seed layer (not shown), a metal layer 50a mainly composed of a first metal element, and a metal layer 50b mainly composed of a second metal element. As described with respect to the frame body 40, the first metal element is, for example, copper or aluminum, and the second metal element is, for example, nickel or platinum. The columnar body 50 has the same layer structure and is made of the same material as the frame body 40. The metal layers 50a and 50b are plating layers formed by an electrolytic plating method.

[0033] A part of the metal layer 62 of the lid 60 has reacted with the solder joint layer 54 to form an alloy layer. The solder joint layer 54 has a flared shape with a gradually increasing width as it extends from the columnar body 50 toward the lid 60. Since the solder joint layer 54 has such a flared shape, the bonding reliability between the columnar body 50 and the lid 60 is improved, and the deflection of the lid 60 can be effectively reduced. The starting point of the flared shape of the solder joint layer 54 is the end of the columnar body 50.

[0034] The metal layer 50a is thicker than the seed layer and the metal layer 50b, and is the thickest metal layer among the metal layers constituting the columnar body 50. Also, the metal layer 50a is thicker than the metal layer 40a of the frame body 40. The thickness of the seed layer is, for example, 0.5 μm or less. The thickness of the metal layer 50a is, for example, about 20 μm to 30 μm. The thickness of the metal layer 50b is about 2 μm to 5 μm. The maximum width of the metal layer 50a is, for example, about 40 μm to 50 μm. Thus, the width of the metal layer 50a is larger than the width of the metal layer 40a of the frame body 40, for example, 1.5 times or more larger, for example, 2 times or more larger.

[0035] The reason why the width of the columnar body 50 is larger than the width of the frame body 40 is as follows. That is, it is preferable for the columnar body 50 to have a large width from the viewpoint of suppressing the deflection of the lid 60, and it is preferable for the frame body 40 to have a narrow width from the viewpoints of miniaturization of the device and securing the formation region of the elastic wave element 30.

[0036] The reason why the height of the columnar body 50 from the support substrate 10 is higher than the height of the frame body 40 from the support substrate 10 is as follows. That is, since the columnar body 50 is wider than the frame body 40, when the columnar body 50 and the frame body 40 are formed simultaneously using the electroplating method, the columnar body 50 becomes higher than the frame body 40 in terms of current density.

[0037] On the lower surface of the lid 60, a step 66 is provided where the distance from the support substrate 10 directly below the columnar body 50 to the lid 60 directly above the columnar body 50 is longer than the distance from the support substrate 10 directly below the frame body 40 to the lid 60 directly above the frame body 40. For example, the step 66 is formed by digging a location directly above the columnar body 50. By forming the step 66 on the lid 60, the difference in height between the columnar body 50 and the frame body 40 can be absorbed. From the point of absorbing the difference in height between the columnar body 50 and the frame body 40, the height of the step 66 is preferably less than twice the difference in height between the columnar body 50 and the frame body 40, more preferably 0.5 times or more and 1.5 times or less, even more preferably 0.7 times or more and 1.3 times or less, and most preferably substantially the same.

[0038] Fig. 2(a) is a bottom view of the lid 60 in Example 1, and Fig. 2(b) is a bottom view of the lid 60a in a modified example of Example 1. As shown in Fig. 2(a), in the lid 60 of Example 1, one recess 68 is formed by the step 66 for a plurality of columnar bodies 50. As shown in Fig. 2(b), in the lid 60a in the modified example of Example 1, one recess 68 is formed by the step 66 for each of the plurality of columnar bodies 50. In the lid 60 of Fig. 2(a), manufacturing becomes easy due to relaxation of the positional accuracy of the recess 68 and the like. In the lid 60a of Fig. 2(b), since the formation area of the recess 68 becomes smaller, the strength of the lid 60 is improved.

[0039] For example, the support substrate 10 is a sapphire substrate with a thickness of 75 μm. The piezoelectric layer 12 is a 42° rotated Y-cut X-propagation lithium tantalate layer with a thickness of 0.6 μm. The seed layer of the frame 40 is a laminate of a titanium layer with a thickness of 0.05 μm and a copper layer with a thickness of 0.325 μm from the support substrate 10 side. The metal layer 40a is a copper layer with a thickness of 21 μm, and the metal layer 40b is a nickel layer with a thickness of 2.5 μm. The solder joint layer 44 is a gold-tin solder layer with a thickness of 4 μm. The maximum width of the metal layer 40a is 23 μm. The seed layer of the columnar body 50 is a laminate of a titanium layer with a thickness of 0.05 μm and a copper layer with a thickness of 0.325 μm from the support substrate 10 side. The metal layer 50a is a copper layer with a thickness of 23 μm to 25 μm, and the metal layer 50b is a nickel layer with a thickness of 2.5 μm. The solder joint layer 54 is a gold-tin solder layer with a thickness of 4 μm. The maximum width of the metal layer 50a is 46 μm. The metal layer 62 of the lid 60 is a laminate of a nickel layer with a thickness of 1 μm and a gold layer with a thickness of 1 μm from the main body 64 side. The main body 64 is a kovar plate with a thickness of 30 μm. The via wiring 16 is a copper layer with a diameter of 40 μm. The terminal 14 is a laminate of a copper layer with a thickness of 2 μm, a nickel layer with a thickness of 5 μm, and a gold layer with a thickness of 0.3 μm from the support substrate 10 side.

[0040] Figure 3 is a plan view of the surface acoustic wave device 30 in Example 1. As shown in Figure 3, the surface acoustic wave device 30 is a surface acoustic wave resonator. An IDT (Interdigital Transducer) 31 and reflectors 32 are provided on the upper surface of the piezoelectric layer 12. The IDT 31 has a pair of opposing comb-shaped electrodes 33. The comb-shaped electrode 33 has a plurality of electrode fingers 34 and a bus bar 35 to which the plurality of electrode fingers 34 are connected. The reflectors 32 are provided on both sides of the IDT 31. The IDT 31 excites surface acoustic waves in the piezoelectric layer 12. The pitch of the electrode fingers 34 of one of the pair of comb-shaped electrodes is approximately equal to the wavelength λ of the acoustic wave. That is, the wavelength λ of the acoustic wave is approximately equal to twice the pitch of the electrode fingers 34 of the pair of comb-shaped electrodes 33. The IDT 31 and the reflectors 32 are formed of a metal film such as aluminum, copper, or molybdenum, for example. A protective film or temperature compensation film covering the IDT 31 and the reflectors 32 may be provided on the upper surface of the piezoelectric layer 12. The comb-shaped electrode 33 may have dummy electrode fingers.

[0041] A filter may be formed by a plurality of surface acoustic wave devices 30 formed on the upper surface of the piezoelectric layer 12, or a duplexer may be formed. FIG. 4(a) is a circuit diagram of the filter, and FIG. 4(b) is a block diagram of the duplexer.

[0042] As shown in FIG. 4(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 P3 are connected in parallel between the input terminal Tin and the output terminal Tout. The series resonators S1 to S4 and the parallel resonators P1 to P3 are surface acoustic wave devices 30. The number of series resonators and parallel resonators can be set as appropriate. Although a ladder filter is described as an example of the filter, the filter may be a multi-mode filter.

[0043] As shown in FIG. 4(b), a transmit filter 90 is connected between the common terminal Ant and the transmit terminal Tx. A receive filter 92 is connected between the common terminal Ant and the receive terminal Rx. The transmit filter 90 passes the signal in the transmit band of the high-frequency signal input from the transmit terminal Tx as a transmit signal to the common terminal Ant, and suppresses signals of other frequencies. The receive filter 92 passes the signal in the receive band of the high-frequency signal input from the common terminal Ant as a receive signal to the receive terminal Rx, and suppresses signals of other frequencies. Although a duplexer is shown as an example of the multiplexer, it may be a triplexer or a quadruplexer.

[0044] [Manufacturing Method] Figs. 5(a) to 6(c) are cross-sectional views showing a method for manufacturing the elastic wave device 100 according to Embodiment 1. As shown in Fig. 5(a), for example, a laser beam is irradiated onto the upper surface of the support substrate 10 to form via holes, and a metal layer such as copper is formed in the via holes using, for example, an electrolytic plating method. Then, the upper surface of the metal layer is planarized using, for example, a CMP (Chemical Mechanical Polishing) method so that the upper surface of the support substrate 10 is exposed. Thereby, via wiring 16 is formed on the support substrate 10. Next, a piezoelectric substrate is bonded to the upper surface of the support substrate 10 at room temperature using, for example, a surface activation method. The support substrate 10 and the piezoelectric substrate may be directly bonded via an amorphous layer of several nm, or may be indirectly bonded via an insulating layer. Then, the upper surface of the piezoelectric substrate is polished using, for example, a CMP method. Thereby, a piezoelectric layer 12 bonded directly or indirectly to the upper surface of the support substrate 10 is formed.

[0045] As shown in Fig. 5(b), a part of the piezoelectric layer 12 is removed using, for example, an etching method. Thereby, the piezoelectric layer 12 in the peripheral region of the support substrate 10 is removed, and the via wiring 16 is exposed. Also, an opening 22 is formed in the piezoelectric layer 12. In the opening 22, for example, the upper surface of the support substrate 10 is exposed. Next, an elastic wave element 30 is formed on the upper surface of the piezoelectric layer 12. A wiring 18 that extends from the upper surface of the piezoelectric layer 12 to the via wiring 16 and electrically connects the elastic wave element 30 and the via wiring 16 is formed.

[0046] As shown in Fig. 5(c), a mask layer 94 having an opening 96 is formed on the upper surface of the support substrate 10 in a region where a frame body 40 and a columnar body 50 are to be formed. The mask layer 94 is formed of, for example, a photoresist.

[0047] As shown in FIG. 6(a), a metal layer is formed in the opening 96 of the mask layer 94, for example, by electrolytic plating. Thereby, a frame body 40 including a seed layer (not shown), a metal layer 40a, and a metal layer 40b, and a solder joint layer 44 on the frame body 40 are formed. Further, a columnar body 50 including a seed layer (not shown), a metal layer 50a, and a metal layer 50b, and a solder joint layer 54 on the columnar body 50 are formed. In this way, the frame body 40 and the columnar body 50 are formed simultaneously by electrolytic plating. Since the columnar body 50 is wider than the frame body 40, the columnar body 50 is formed at a higher height from the support substrate 10 than the frame body 40 in terms of the current density in the electrolytic plating method. In particular, the thickest metal layer 50a among the metal layers of the columnar body 50 is formed thicker than the thickest metal layer 40a among the metal layers of the frame body 40.

[0048] As shown in FIG. 6(b), after removing the mask layer 94, a lid 60 is joined to the solder joint layer 44 on the frame body 40 and the solder joint layer 54 on the columnar body 50. The metal layer 62 of the lid 60 reacts with the solder joint layers 44 and 54 to form an alloy. The elastic wave element 30 is sealed in the gap 20 by the lid 60, the frame body 40, and the solder joint layer 44. A step 66 is formed in the lid 60 in advance. The columnar body 50 is joined to the recessed surface 70 by the step 66 with the solder joint layer 54, and the frame body 40 is joined to the surface 72 protruding from the surface 70 with the solder joint layer 44. Thereby, the height difference between the columnar body 50 and the frame body 40 is absorbed by the height of the step 66. For this reason, the solder joint layer 44 has a flaring shape in which the width gradually increases from the frame body 40 toward the lid 60, and the solder joint layer 54 has a flaring shape in which the width gradually increases from the columnar body 50 toward the lid 60.

[0049] As shown in FIG. 6(c), the lower surface of the support substrate 10 is polished, for example, by CMP method. Thereby, the via wiring 16 is exposed from the lower surface of the support substrate 10. Next, a terminal 14 connected to the via wiring 16 is formed on the lower surface of the support substrate 10. Thus, the elastic wave device 100 according to Example 1 is manufactured.

[0050] [Comparative Example] FIG. 7 is a cross-sectional view of the elastic wave device 500 according to the comparative example. As shown in FIG. 7, in the elastic wave device 500, a lid 60b without a step is used. Since other configurations are the same as those in the first embodiment, the description thereof is omitted.

[0051] In the elastic wave device 500 of the comparative example, the solder joint layer 54 that joins the columnar body 50 and the lid 60b has a flaring shape in which the width gradually increases from the columnar body 50 toward the lid 60b. On the other hand, the solder joint layer 44 that joins the frame body 40 and the lid 60b has a constricted shape with a constriction where the width narrows between the frame body 40 and the lid 60b.

[0052] It is considered that the reason why the solder joint layer 44 has a constricted shape is as follows. Since the columnar body 50 is higher than the frame body 40, when a lid 60b without a step is used, when the distance between the columnar body 50 and the lid 60b becomes about the thickness of the solder joint layer 54, the distance between the frame body 40 and the lid 60b becomes larger than the thickness of the solder joint layer 44. For this reason, the columnar body 50 and the lid 60b are joined in a state where an appropriate load is applied to the solder joint layer 54, while the frame body 40 and the lid 60b are joined in a state where an appropriate load is not applied to the solder joint layer 44. For this reason, it is considered that the solder joint layer 54 has an appropriate flaring shape in which the width gradually increases from the columnar body 50 toward the lid 60b, while the solder joint layer 44 has a constricted shape in which the width narrows between the frame body 40 and the lid 60b.

[0053] When the solder joint layer 44 has a constricted shape, a narrow portion is formed, resulting in a decrease in the airtightness of the gap 20. In addition, the formation of a narrow portion causes a decrease in mechanical strength, for example, a decrease in reliability against dropping.

[0054] On the one hand, according to Example 1, as shown in FIG. 1(b), the solder joint layer 54 (the second solder joint layer) has a flared shape with a gradually increasing width from the columnar body 50 toward the lid 60 in a cross-sectional view. Thereby, the joinability between the columnar body 50 and the lid 60 is improved, and the deflection of the lid 60 can be effectively suppressed. Further, the solder joint layer 44 (the first solder joint layer) has a flared shape with a gradually increasing width from the frame body 40 toward the lid 60 in a cross-sectional view. Thereby, even when the columnar body 50 is higher from the support substrate 10 than the frame body 40, the joinability between the frame body 40 and the lid 60 is improved, and a decrease in the airtightness of the gap 20 can be suppressed. Also, since the joinability between the frame body 40 and the lid 60 is improved, even if the width of the frame body 40 is narrowed, a decrease in the airtightness of the gap 20 can be suppressed, so that the device can be miniaturized and the formation region of the surface acoustic wave element 30 can be expanded. Further, since the solder joint layers 44 and 54 have a flared shape and the joinability is improved, a decrease in mechanical strength can also be suppressed.

[0055] Also, in Example 1, the lid 60 has a step 66 in which the distance from the support substrate 10 directly below the columnar body 50 to the lid 60 directly above the columnar body 50 is longer than the distance from the support substrate 10 directly below the frame body 40 to the lid 60 directly above the frame body 40. Thereby, the height difference between the columnar body 50 and the frame body 40 can be absorbed by the height of the step 66 provided in the lid 60, and the solder joint layers 44 and 54 can have a flared shape with a gradually increasing width from the frame body 40 or the columnar body 50 toward the lid 60.

[0056] From the perspective of absorbing the height difference between the columnar body 50 and the frame body 40 and making both the solder joint layers 44 and 54 fan-shaped, the lid 60 preferably has a step 66 such that the difference between the distance from the support substrate 10 directly below the columnar body 50 to the lid 60 directly above the columnar body 50 and the distance from the support substrate 10 directly below the frame body 40 to the lid 60 directly above the frame body 40 is 0.5 times or more and 1.5 times or less the difference between the height of the columnar body 50 and the height of the frame body 40. More preferably, the lid 60 has a step 66 with substantially the same height as the difference between the height of the columnar body 50 and the height of the frame body 40. "Substantially the same" means within 5% of the difference between the height of the columnar body 50 and the height of the frame body 40, that is, 95% to 105% when the difference between the height of the columnar body 50 and the height of the frame body 40 is taken as 100%.

[0057] Also, in Example 1, the frame body 40 and the columnar body 50 are plating layers, and in a cross-sectional view, the width of the columnar body 50 is larger than the width of the frame body 40. When the frame body 40 and the columnar body 50 are simultaneously formed by the electroplating method, since the width of the columnar body 50 is larger than the width of the frame body 40, the columnar body 50 becomes higher than the frame body 40. Therefore, in such a case, it is preferable that the lid 60 has a step 66 such that the distance from the support substrate 10 directly below the columnar body 50 to the lid 60 directly above the columnar body 50 is longer than the distance from the support substrate 10 directly below the frame body 40 to the lid 60 directly above the frame body 40.

[0058] Also, in Example 1, for the frame body 40 and the columnar body 50, the thickest metal layers 40a and 50a are copper plating layers. When the copper plating layers have different widths, they are likely to be formed with different heights. Therefore, when the thickest metal layers 40a and 50a are copper plating layers, it is preferable that the lid 60 has a step 66 such that the distance from the support substrate 10 directly below the columnar body 50 to the lid 60 directly above the columnar body 50 is longer than the distance from the support substrate 10 directly below the frame body 40 to the lid 60 directly above the frame body 40.

Example

[0059] FIG. 8 is a cross-sectional view of the elastic wave device 200 according to Embodiment 2. As shown in FIG. 8, in the elastic wave device 200, a lid 60b without a step is used, but on the upper surface of the support substrate 10a, a step 11 is formed on the support substrate 10 directly below the columnar body 50 to the lid 60 directly above the columnar body 50, and the distance is longer than the distance from the support substrate 10 directly below the frame body 40 to the lid 60 directly above the frame body 40. For example, the step 11 is formed by digging a location directly below the columnar body 50 of the support substrate 10a. By forming the step 11 on the support substrate 10a, the difference in height between the columnar body 50 and the frame body 40 is absorbed. Therefore, the solder joint layer 44 has a flared shape with a gradually increasing width from the frame body 40 toward the lid 60, and the solder joint layer 54 has a flared shape with a gradually increasing width from the columnar body 50 toward the lid 60. From the point of absorbing the difference in height between the columnar body 50 and the frame body 40, the height of the step 11 is preferably less than twice the difference in height between the columnar body 50 and the frame body 40, more preferably 0.5 times or more and 1.5 times or less, still more preferably 0.7 times or more and 1.3 times or less, and even more preferably substantially the same. Since other configurations are the same as those in Embodiment 1, the description thereof is omitted.

[0060] FIG. 9(a) is a top view of the support substrate 10a in Embodiment 2, and FIG. 9(b) is a top view of the support substrate 10b in a modified example of Embodiment 2. As shown in FIG. 9(a), in the support substrate 10a in Embodiment 2, one recess 13 is formed by the step 11 for each of the plurality of columnar bodies 50. As shown in FIG. 9(b), in the support substrate 10b in the modified example of Embodiment 2, one recess 13 is formed by the step 11 for the plurality of columnar bodies 50. In the support substrate 10a of FIG. 9(a), since the piezoelectric layer 12 and the wiring 18 do not need to be formed on the step 66, the piezoelectric layer 12 and the wiring 18 are not damaged by being provided on the step. In the support substrate 10b of FIG. 9(b), manufacturing becomes easy due to relaxation of the positional accuracy of the recess 13 and the like.

[0061] The elastic wave device 200 according to Embodiment 2 is manufactured by the same method as the method described with reference to FIGS. 5(a) to 6(c), except that after forming the opening 22 in the piezoelectric layer 12, a part of the support substrate 10 is removed using, for example, an etching method to form the recess 13 by the step 11, and a lid 60b without a formed step is used.

[0062] According to Embodiment 2, as shown in FIG. 8, the solder joint layer 54 (second solder joint layer) has a flared shape in which the width gradually increases from the columnar body 50 toward the lid 60 in a cross-sectional view. The solder joint layer 44 (first solder joint layer) has a flared shape in which the width gradually increases from the frame body 40 toward the lid 60 in a cross-sectional view. Thereby, similarly to Embodiment 1, the joinability between the columnar body 50 and the lid 60 is improved, and the joinability between the frame body 40 and the lid 60 is improved, suppressing a decrease in the airtightness of the gap 20.

[0063] Further, in Embodiment 2, the support substrate 10a has a step 11 in which the distance from the support substrate 10 directly below the columnar body 50 to the lid 60 directly above the columnar body 50 is longer than the distance from the support substrate 10 directly below the frame body 40 to the lid 60 directly above the frame body 40. Thereby, the height difference between the columnar body 50 and the frame body 40 can be absorbed by the height of the step 11 provided in the support substrate 10a, and the solder joint layers 44 and 54 can have a flared shape in which the width gradually increases from the frame body 40 or the columnar body 50 toward the lid 60.

[0064] From the perspective of absorbing the height difference between the columnar body 50 and the frame body 40 and making both the solder joint layers 44 and 54 fan-shaped, it is preferable that the support substrate 10a has a step 11 such that the difference between the distance from the support substrate 10 directly below the columnar body 50 to the lid 60 directly above the columnar body 50 and the distance from the support substrate 10 directly below the frame body 40 to the lid 60 directly above the frame body 40 is 0.5 times or more and 1.5 times or less the difference between the height of the columnar body 50 and the height of the frame body 40. More preferably, the support substrate 10a has a step 11 with a height substantially the same as the difference between the height of the columnar body 50 and the height of the frame body 40. Substantially the same means within 5% of the difference between the height of the columnar body 50 and the height of the frame body 40, that is, 95% to 105% when the difference between the height of the columnar body 50 and the height of the frame body 40 is taken as 100%.

[0065] In Example 1, the case where the lid 60 provided with the step 66 was used, and in Example 2, the case where the support substrate 10a provided with the step 11 was used were shown as examples, but both the lid 60 and the support substrate 10a may be used. In this case, it is preferable that the total height of the step 66 and the step 11 is less than twice the difference between the height of the columnar body 50 and the height of the frame body 40, more preferably 0.5 times or more and 1.5 times or less, even more preferably 0.7 times or more and 1.3 times or less, and even more preferably substantially the same.

Example

[0066] FIG. 10 is a cross-sectional view of the surface acoustic wave device 300 according to Example 3. As shown in FIG. 10, in the surface acoustic wave device 300, via wirings 16 are provided on the support substrate 10 directly below the columnar body 50, and wirings 18 extending between the surface acoustic wave element 30 and the columnar body 50 and the via wirings 16 are provided. When the terminal 14 connected to the via wiring 16 directly below the columnar body 50 is a ground terminal, a ground potential is supplied to the lid 60 to provide a shielding effect. Since the other configurations are the same as those in Example 1, the description thereof is omitted. The surface acoustic wave device 300 according to Example 3 is manufactured by the same method as the method described with reference to FIGS. 5(a) to 6(c).

[0067] According to Example 3, as shown in FIG. 10, via wiring 16 is provided on the support substrate 10 located directly below the columnar body 50. Wiring 18 is provided to connect between the columnar body 50 and the via wiring 16 directly below the columnar body 50 from the elastic wave element 30. In this case, the height difference between the columnar body 50 and the frame body 40 becomes even larger. Therefore, in such a case, it is preferable that a step 66 is provided on the lid 60. Note that the support substrate 10a shown in Example 2 may be used instead of the support substrate 10. That is, instead of or in addition to using the lid 60 provided with the step 66, the support substrate 10a provided with the step 11 may be used.

[0068] In Examples 1 to 3, the case where the piezoelectric layer 12 is provided on the support substrates 10 and 10a is shown as an example, but the piezoelectric layer 12 may be a thick piezoelectric substrate without the support substrates 10 and 10a.

Example

[0069] FIG. 11(a) is a cross-sectional view of an elastic wave device 400 according to Example 4, and FIG. 11(b) is a cross-sectional view of the elastic wave element 30a in Example 4. As shown in FIGS. 11(a) and 11(b), in the elastic wave device 400, an elastic wave element 30a is provided on the support substrate 10 instead of the elastic wave element 30. The elastic wave element 30a is a piezoelectric thin film resonator. The elastic wave element 30a includes a piezoelectric layer 82 provided on the support substrate 10, and a lower electrode 81 and an upper electrode 83 sandwiching the piezoelectric layer 82. A gap 84 is formed between the lower electrode 81 and the support substrate 10. A region where the lower electrode 81 and the upper electrode 83 face each other with at least a part of the piezoelectric layer 82 interposed therebetween is a resonance region 87. In the resonance region 87, the lower electrode 81 and the upper electrode 83 excite an elastic wave in the thickness longitudinal vibration mode in the piezoelectric layer 82. Note that an insertion film for increasing the Q value or for temperature compensation may be inserted in the outer peripheral region of the resonance region 87 of the piezoelectric layer 82.

[0070] The lower electrode 81 and the upper electrode 83 are metal films including, for example, a ruthenium film or the like. The piezoelectric layer 82 is, for example, an aluminum nitride layer or a zinc oxide layer. An acoustic reflection film that reflects elastic waves may be provided instead of the void 84. The elastic wave element 30a is manufactured by a generally known method.

[0071] As in Examples 1 to 3, the functional element provided on the support substrate 10 may be the elastic wave element 30 including the comb-shaped electrode 33 provided on the piezoelectric layer 12 which is a single crystal lithium tantalate layer or a single crystal lithium niobate layer. As in Example 4, the functional element may be the elastic wave element 30a which is a piezoelectric thin film resonator provided with the lower electrode 81 and the upper electrode 83 sandwiching the piezoelectric layer 82. Further, the functional element may be other than the elastic wave element, such as a piezoelectric element such as a MEMS (Micro Electro Mechanical System) element, or other cases.

[0072] As described above in detail, the embodiments of the present invention have been described, but the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Explanation of Reference Numerals

[0073] 10, 10a, 10b Support substrate 11 Step 12 Piezoelectric layer 13 Recess 14 Terminal 16 Via wiring 18 Wiring 20 Void 22 Opening 30, 30a Elastic wave element 31 IDT 32 Reflector 33 Comb-shaped electrode 34 Electrode finger 35 Bus bar 40 Frame 40a, 40b Metal layer 44 Solder joint layer 50 Columnar body Metal layers 50a and 50b Soldering layer 54 Lids 60, 60a, and 60b Metal layer 62 Body 64 Step 66 Recess 68 Surfaces 70 and 72 Lower electrode 81 Piezoelectric layer 82 Upper electrode 83 Void 84 Resonance region 87 Transmission filter 90 Receiving filter 92 Mask layer 94 Opening 96 Elastic wave devices 100, 200, 300, 400, and 500

Claims

1. A substrate, functional elements provided on the substrate, a metal frame provided on the substrate so as to surround the functional elements in a plan view, a lid provided on the frame and sandwiching a gap with the substrate, a first solder joint layer that joins the frame and the lid to seal the functional elements in the gap and has a flared shape in which the width increases gradually from the frame toward the lid in a cross-section in the thickness direction of the substrate, a metal columnar body provided between the substrate and the lid in the gap and having a height higher than that of the substrate from the frame, a second solder joint layer that joins the columnar body and the lid and has a flared shape in which the width increases gradually from the columnar body toward the lid in a cross-section in the thickness direction of the substrate, and an electronic component comprising the same.

2. The electronic component according to claim 1, wherein at least one of the lid and the substrate has a step in which the distance from the substrate directly below the columnar body to the lid directly above the columnar body is longer than the distance from the substrate directly below the frame to the lid directly above the frame.

3. At least one of the lid and the substrate has a step in which the distance from the substrate directly below the columnar body to the lid directly above the columnar body is longer than the distance from the substrate directly below the frame to the lid directly above the frame, The electronic component according to claim 1, wherein the total height of the steps of at least one of the lid and the substrate is 0.5 times or more and 1.5 times or less the difference between the height of the columnar body and the height of the frame.

4. The electronic component according to claim 2 or 3, wherein the total height of the steps of at least one of the lid and the substrate is substantially the same as the difference between the height of the columnar body and the height of the frame.

5. The electronic component according to claim 2 or 3, wherein the lid has a step having a height substantially the same as the difference between the height of the columnar body and the height of the frame.

6. The electronic component according to claim 2 or 3, wherein the substrate has a step having a height substantially the same as the difference between the height of the columnar body and the height of the frame.

7. The frame and the columnar body are plating layers, The electronic component according to any one of claims 1 to 6, wherein the maximum width of the columnar body is larger than the maximum width of the frame.

8. A via wiring provided on the substrate and positioned directly below the columnar body and electrically connected to the columnar body, The electronic component according to any one of claims 1 to 7, comprising wiring provided between the functional element and the columnar body and the via wiring.

9. The electronic component according to any one of claims 1 to 8, wherein the functional element is an elastic wave element.

10. The electronic component according to claim 9, wherein a filter is formed by the elastic wave element.

11. The electronic component according to claim 10, wherein a multiplexer is formed by the filter.

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