JP7466723B2 - Electronic Devices - Google Patents

Description

The present disclosure relates to an electronic device in which a space is located between a substrate and a chip.

For example, Patent Document 1 (surface acoustic wave device) is known as an electronic device using an acoustic wave chip. The surface acoustic wave device disclosed in Patent Document 1 has a circuit wiring board, a surface acoustic wave element mounted on the circuit wiring board, and a sealing resin that surrounds the outer periphery of the surface acoustic wave element and is joined to the circuit wiring board. A space is located between the circuit wiring board and the surface acoustic wave element.

JP 2017-175427 A

There is a need for durable electronic devices.

An electronic device according to one aspect of the present disclosure includes a base having a first surface and a first pad located on the first surface;
a bonding member bonded to the first surface and having a first opening surrounding the first pad;
a first chip facing the first surface through the first opening and connected to the first pad;
a sealing portion that covers an outer peripheral surface of the first chip and is joined to the base body via the joining member;
having
The glass transition temperature of the joining member is higher than the glass transition temperature of the sealing portion.

The above configuration makes it possible to provide a durable electronic device.

FIG. 1 is a perspective view of a base structure according to an embodiment. 2 is a cross-sectional view of the substrate structure shown in FIG. 1 taken along line II-II. FIG. 3 is an enlarged view of III shown in FIG. 2. FIG. 3 is a perspective view of the first chip or the second chip shown in FIG. 2 . FIG. 5A is a diagram explaining the process of forming first and second bumps on the base structure and placing a mounting body on the base structure, FIG. 5B is a diagram explaining the process of mounting the mounting body on the base structure, and FIG. 5C is an enlarged view of Vc in FIG. 5B. 6A is a diagram showing the periphery of a first chip in a first modified example of the electronic device shown in FIG. 2, and FIG. 6B is a diagram showing the periphery of the first chip in a second modified example of the electronic device shown in FIG. 2. FIG. 3 shows a third variant of the electronic device shown in FIG. 2 .

Embodiments of the present disclosure will be described below with reference to the attached drawings. With respect to the front, back, left, right, top and bottom directions, Fr indicates front, Rr indicates rear, Le indicates left, Ri indicates right, Up indicates top, and Dn indicates bottom, based on FIG. 1. Note that each of the drawings referred to is shown diagrammatically, and some details may be omitted.

[Embodiment]
(Electronic Devices)
Please refer to Fig. 1. The electronic device 1 has, for example, a plurality of external terminals 23A-23F (details will be described later) that are connected to an external device. The electronic device 1 is mounted on the external device by connecting these external terminals 23A-23F to the external device. The electronic device 1 shown in Fig. 1 has a base structure 10 and a mounting body 2 mounted on this base structure 10.

(Base Structure)
The base structure 10 has, for example, a flat plate shape. The base structure 10 having a flat plate shape may have, for example, a rectangular shape, a circular shape, or an elliptical shape when viewed in the thickness direction. Furthermore, the base structure 10 may be larger than the mounting body 2, may be smaller than the mounting body 2, or may be the same size as the mounting body 2. The thickness of the base structure 10 may be, for example, 70 μm or more, 200 μm or more, 400 μm or more, or 700 μm or more. The size and shape of the base structure 10 are arbitrary.

Refer to Figures 1 and 2. For example, the base structure 10 has a base 20 and a joining member 30 joined to the base 20.

(Base)
The substrate 20 shown in Fig. 2 is a multilayer board having three or more conductor layers. However, in other embodiments, the substrate 20 may be a double-sided board having a total of two conductor layers only on the upper and lower surfaces, or a single-layer board having a conductor layer only on the upper surface. The substrate 20 of the multilayer board will be described below.

The base 20 is, for example, a substrate having a flat plate shape. The base 20 occupies, for example, a large portion (e.g., 80% or more) of the base structure 10. In one embodiment, the size and shape of the base 20 can be the same as those of the base structure 10. However, the base 20 may occupy, for example, 80% or less of the base structure 10.

The linear expansion coefficient of the base 20 can be set to any value. For example, the linear expansion coefficient of the base 20 may be 4 to 12 ppm/K, or 5 to 10 ppm/K. For example, the linear expansion coefficient of the base 20 in the horizontal direction (front-back and left-right directions) may be 4 to 8 ppm/K, and the linear expansion coefficient of the base 20 in the vertical direction may be 6 to 12 ppm/K. That is, the linear expansion coefficient of the base 20 may be different in the horizontal direction and the vertical direction. The linear expansion coefficient of the base 20 can be determined, for example, by changing the temperature of the base 20 according to a program and measuring the dimensional change of the base 20 while applying a uniform pressure to the base 20 in the process. Thermomechanical analysis (TMA method) can be used as one such measurement method.

The glass transition temperature of the substrate 20 may be, for example, 270°C or less, 260°C or less, 250°C or less, or 240°C or less. In one embodiment, the glass transition temperature of the substrate 20 may be set within the range of 240 to 270°C. The material of the substrate 20 is arbitrary. For example, the material of the substrate 20 may be selected so that the glass transition temperature is a predetermined value. The glass transition temperature of the substrate 20 can be determined, for example, by thermomechanical analysis (TMA method) in which the temperature of the substrate 20 is changed according to a program and the change in physical properties at that time is measured. The same method may be used to measure the glass transition temperature of the joining member 30 and the sealing portion 60, etc., which will be described later.

The Young's modulus of the base body 20 is arbitrary. For example, the Young's modulus of the base body 20 may be 12 to 40 GPa, or 15 to 33 GPa.

The base 20 shown in FIG. 2 has an insulating base body 21, a number of pads 22A-22D located on the upper surface 21a of the base body 21, a number of external terminals 23A-23F (see FIG. 1) located on the lower surface 21b of the base body 21, an internal conductor 24 that connects the pads 22A-22D and the external terminals 23A-23F and is located inside the base body 21, and a fibrous body 25 located inside the base body 21.

The material of the base body 21 is arbitrary. For example, the material of the base body 21 may be an inorganic material or an organic material. Examples of inorganic materials include ceramics and amorphous materials in which multiple inorganic particles are bonded to each other. Examples of organic materials include thermosetting resins. Examples of thermosetting resins include epoxy resins, phenolic resins, melamine resins, bismaleimide triazine resins, urea resins, and unsaturated polyester resins. In this embodiment, the case where the material of the base body 21 is an organic material is taken as an example.

The base body part 21 shown in FIG. 2 has a first surface 21a to which the joining member 30 is joined, a second surface 21b located on the opposite side of the first surface 21a, and a third surface 21c connecting the first surface 21a and the second surface 21b. The first surface 21a constitutes the upper surface of the base body part 21, the second surface 21b constitutes the lower surface of the base body part 21, and the third surface 21c constitutes the side surface of the base body part 21.

See FIG. 2 and FIG. 3. The thickness and shape of the pads 22A to 22D are arbitrary. For example, the thickness (vertical direction) of the pads 22A to 22D is 1 μm or more and 50 μm or less. The pads 22A to 22D may all have the same thickness, or may have different thicknesses, or only some of the pads may have a different thickness in relation to the other pads. The shape of the pads 22A to 22D in a plan view may be, for example, circular, elliptical, or rectangular. The pads 22A to 22D may all have the same shape, or only some of the pads may have a different shape in relation to the other pads. Hereinafter, one arbitrarily selected from the multiple pads 22A to 22D may simply be referred to as pad 22.

See Figures 1 and 2. The number of pads 22 can be set arbitrarily. For example, the number of pads 22 may be four or more, or eight or more. The number of pads 22 may be set to match the number of external terminals 23.

The external terminals 23A-23F may have any size and shape. The external terminals 23A-23F may have, for example, a rectangular flat plate shape, or a needle shape with a predetermined length in the vertical direction. The multiple external terminals 23A-23F may all be the same size, or may have different sizes, or there may be a mixture of external terminals of different sizes and external terminals of the same size. The external terminals 23A-23F shown in FIG. 2 each have a rectangular flat plate shape. Hereinafter, an arbitrarily selected one of the multiple external terminals 23A-23F may simply be referred to as external terminal 23.

The number of external terminals 23 can be set arbitrarily. For example, the number of external terminals 23 may be 3 or more, 6 or more, or 12 or more.

The internal conductor 24 is composed of a via conductor and a conductor pattern. The via conductor and the conductor pattern are continuous with each other. The diameter of the via conductor may be, for example, 60 μm or more and 200 μm or less. The via conductor may have, for example, a circular or rectangular cross-sectional shape. The conductor pattern has a layered shape. The thickness of the conductor pattern may be, for example, 10 μm or more and 100 μm or less.

The fibrous body 25 is, for example, a nonwoven fabric or a woven fabric. FIG. 2 shows a fibrous body 25 including a woven fabric. The fibrous body 25 shown in FIG. 2 has warp threads 25a made of fibers extending in the front-rear direction and weft threads 25b made of weft threads 25b extending left-right. The warp threads 25a and weft threads 25b may be made only of glass fibers, or may be made only of carbon fibers, or may be made partially of glass fibers and the remaining part of a material other than glass (e.g., carbon fiber). When the fibrous body 25 includes glass fibers, it can be said that the fibrous body 25 is a glass cloth. Glass cloth includes glass fibers. Glass fibers (glass) include, for example, silicon dioxide (SiO2) as a main component.

In addition to the above configuration, a solder resist may be applied to the first surface 21a of the base 20.

(Joining member)
The joining member 30 shown in Fig. 2 is located between the base body 20 and the mounting body 2, and joins them together. The shape of the joining member 30 is arbitrary. The joining member 30 shown in Fig. 1 has a layered shape (including a flat plate shape). The joining member 30 may have a rectangular shape or a circular shape in a planar perspective view. The shape of the joining member 30 may be changed to match the surface of the base body 20 to which the joining member 30 is joined.

Refer to Figures 2 and 3. In a plan view, the joining member 30 may be slightly larger than the first surface 21a, may be smaller than the first surface 21a of the base 20, or may be the same size as the first surface 21a of the base 20. The thickness of the joining member 30 may be 1/2 or less, 1/4 or less, 1/8 or less, 1/16 or less, 1/32 or less, or 1/2 or more of the thickness of the base 20. It may be thicker or thinner than the pads 22A to 22D. The thickness of the joining member 30 is, for example, 10 μm or more and 100 μm or less.

The linear expansion coefficient of the joining member 30 can be set arbitrarily. For example, the linear expansion coefficient of the joining member 30 may be 1 to 8 ppm/K, or 3 to 5 ppm/K. For example, the linear expansion coefficient of the joining member 30 may be different in the horizontal direction and the vertical direction, or may be the same in the horizontal direction and the vertical direction. For example, the linear expansion coefficient of the joining member 30 may be smaller than the linear expansion coefficient of the base body 20. More specifically, the linear expansion coefficient of the joining member 30 may be smaller than the linear expansion coefficient of the base body 20 in the horizontal direction and the vertical direction.

The glass transition temperature of the joining member 30 may be, for example, 250°C or higher, 260°C or higher, or 270°C or higher. For example, the glass transition temperature of the joining member 30 may be higher than the glass transition temperature of the base 20. However, the glass transition temperature of the joining member 30 may be the same as the glass transition temperature of the base 20, or may be lower than the glass transition temperature of the base 20. For example, the material of the joining member 30 may be selected so that the glass transition temperature is a desired value.

The Young's modulus of the joining member 30 is arbitrary. The Young's modulus of the joining member 30 may be greater than the Young's modulus of the base body 20, may be the same as the Young's modulus of the base body 20, or may be smaller than the Young's modulus of the base body 20. For example, the Young's modulus of the joining member 30 may be set within the range of 15 to 150 GPa, may be set within the range of 30 to 100 GPa, or may be set within the range of 45 to 100 GPa.

The joining member 30 shown in FIG. 2 has two openings 31 and 32 that open on the upper and lower surfaces of the joining member 30. One opening 31 (the opening 31 located on the left side in FIG. 2) is called the first opening 31, and the other opening 32 (the opening 32 located on the right side in FIG. 2) is called the second opening 32. A space of a predetermined size is formed inside the first opening 31, and pads 22A and 22B (hereinafter referred to as "first pads 22A and 22B") are located therein. On the other hand, a space of a predetermined size is formed inside the second opening 32, and pads 22C and 22D (hereinafter referred to as "second pads 22C and 22D") are located therein. The inner wall 31a of the first opening 31 surrounds the first pads 22A and 22B, and the inner wall 32a of the second opening 32 surrounds the second pads 22C and 22D. The first opening 31 and the second opening 32 are opened, for example, by a laser or punching. The portion of the joining member 30 excluding the first opening 31 and the second opening 32 (the portion filled with the material that constitutes the joining member 30) is called the solid portion 33.

The size and shape of the first opening 31 and the second opening 32 are arbitrary. The first opening 31 and the second opening 32 may be the same size or different sizes. In planar perspective, the first opening 31 and the second opening 32 may be rectangular, circular, or elliptical. In planar perspective, the first opening 31 and the second opening 32 may have the same shape or different shapes.

The joining member 30 has a reinforcing material 34 and a base material 35 impregnated in the reinforcing material 34.

(Reinforcing material)
For example, the reinforcing material 34 is a cloth. The cloth may be a woven cloth or a non-woven cloth. Fig. 2 shows the reinforcing material 34 that is a woven cloth. The density of the reinforcing material 34 may be set arbitrarily.

The size and shape of the reinforcing material 34 are arbitrary. In planar perspective, the reinforcing material 34 may be larger than the base material 35, may be the same size as the base material 35, or may be smaller than the base material 35. Furthermore, the reinforcing material 34 may be thinner or thicker than the base material 35 in the vertical direction. The thickness of the reinforcing material 34 is, for example, 10 μm or more and 100 μm or less. In planar perspective, the reinforcing material 34 may have, for example, a rectangular shape or a circular shape.

The reinforcing material 34 shown in FIG. 2 has warp threads 34a extending in the front-to-rear direction and weft threads 34b that cross the warp threads 34a and extend in the left-to-right direction. Please also refer to FIG. 3. The warp threads 34a are made up of a number of fibers that extend in the front-to-rear direction. On the other hand, the weft threads 34b are made up of a number of fibers that extend in the left-to-right direction. Note that the weaving method of the reinforcing material 34 is not limited to a woven fabric including the warp threads 34a and the weft threads 34b.

The warp threads 34a and the weft threads 34b may be made of, for example, only glass fiber, or only carbon fiber. Furthermore, the warp threads 34a and the weft threads 34b may be made of a part of glass fiber, and the remaining part of a material other than glass (for example, carbon fiber). When the warp threads 34a and the weft threads 34b contain glass fiber, it can be said that the reinforcing material 34 (cloth) is glass cloth. The glass cloth may contain, for example, glass containing silicon dioxide (SiO ₂ ) as a main component.

For example, the fibers constituting the reinforcing material 34 may be selected from the viewpoint of improving the glass transition temperature. For example, the glass transition temperature may be improved by making the reinforcing material 34 out of glass fibers. Furthermore, the glass transition temperature may be improved by changing the density of the reinforcing material 34 (density of the warp threads 34a and the weft threads 34b). For example, the glass transition temperature may be improved by increasing the warp thread density and/or the weft thread density.

The warp threads 34a may have an elongated shape with multiple fibers arranged horizontally when viewed in a cross section perpendicular to the direction in which the warp threads 34a extend. On the other hand, the weft threads 34b may have an elongated shape with multiple fibers arranged horizontally when viewed in a cross section perpendicular to the direction in which the weft threads 34b extend. By having the warp threads 34a and weft threads 34b in such shapes, the glass cloth (fabric) can be made thin. This makes the base structure 10 compact.

The reinforcing material 34 shown in FIG. 2 is entirely located inside the base material 35. However, in other embodiments, the reinforcing material 34 may be, for example, partially (e.g., most of) located inside the base material 35, with the remainder exposed from the surface of the base material 35 to the outside of the base material 35.

(Base material)
The base material 35 shown in Fig. 2 generally constitutes the outer shape of the joining member 30. Therefore, the size and shape of the base material 35 shown in Fig. 2 can be based on the size and shape of the joining member 30. However, the base material 35 may be smaller in its entirety than the reinforcing material 34 and may not constitute the outer shape of the reinforcing material 34.

Refer to FIG. 2. The base material 35 is, for example, a resin. Examples of the resin include thermosetting resins such as epoxy resin, phenolic resin, melamine resin, bismaleimide triazine resin, urea resin, and unsaturated polyester resin.

(Implementation body)
The mounting body 2 is joined to the base 20 via a joining member 30. The size of the mounting body 2 is arbitrary. The mounting body 2 may be larger than the base structure 10, may be smaller than the base structure 10, or may be the same size as the base structure 10. The shape of the mounting body 2 is arbitrary. For example, the mounting body 2 may have a rectangular plate shape, or may not have a rectangular shape.

The mounting body 2 shown in FIG. 2 has a first chip 40 connected to the first pads 22A and 22B, a second chip 50 connected to the second pads 22C and 22D, and a sealing portion 60 that covers the outer surfaces of the first chip 40 and the second chip 50 and is joined to the joining member 30 (base structure 10).

The first chip 40 and the second chip 50 are, for example, elastic wave chips that can output a predetermined electrical signal by utilizing the characteristic that an elastic wave propagates when an electrical signal is input. The elastic wave may be, for example, a SAW (Surface Acoustic Wave) or a BAW (Bulk Acoustic Wave). Furthermore, the elastic wave chip may simply be called a chip. The elastic wave chip may be, for example, a chip having an elastic wave resonator or a chip having an elastic wave filter. The first chip 40 and the second chip 50 may be MEMS (Micro Electro Mechanical Systems). Please also refer to FIG. 4. FIG. 4 shows a schematic diagram of a chip having a one-port SAW resonator. For example, such a first chip 40 and a second chip 50 are connected to the first pads 22A, 22B and the second pads 22C, 22D and mounted on the base structure 10.

(First chip)
2, the first chip 40 is located above a first opening 31 formed in the bonding member 30, faces the first surface 21a through the first opening 31, and is bonded to the first pads 22A and 22B. The first chip 40 is bonded to the first pads 22A and 22B through bumps 3A and 3B (first bumps 3A and 3B described below).

Refer to FIG. 4. The first chip 40 shown in FIG. 4 has a first chip substrate 41, a first excitation electrode 42 located on the surface (lower surface) of the first chip substrate 41, a pair of first reflectors 43A, 43B sandwiching the first excitation electrode 42, two first terminals 44A, 44B located away from the first excitation electrode 42, and first connection portions 45A, 45B connecting the first terminals 44A, 44B and the first excitation electrode 42.

The size and shape of the first chip substrate 41 are arbitrary. The first chip substrate 41 may have a rectangular flat plate shape or a circular flat plate shape. The thickness of the first chip substrate 41 is, for example, 100 μm or more and 500 μm or less.

See also FIG. 2. The first chip substrate 41 has a first opposing surface 41a facing the base 20, a first opposing surface 41b located on the opposite side of the first opposing surface 41a, and a first side surface 41c connecting the first opposing surface 41a and the first opposing surface 41b. The first terminals 44A and 44B are located on the first opposing surface 41a.

Refer to FIG. 3 and FIG. 4. The first opposing surface 41a shown in FIG. 3 is the lower surface of the first chip substrate 41, and faces the first surface 21a through the first opening 31. FIG. 3 shows a diagram in which a part of the sealing portion 60 is interposed between the first opposing surface 41a and the joining member 30. However, a part of the sealing portion 60 may not be interposed between the first opposing surface 41a and the joining member 30. In other words, the first opposing surface 41a may not abut the upper surface of the joining member 30, or may abut the upper surface of the joining member 30. A part of the sealing portion 60 (first extension portion 66) located between the first opposing surface 41a and the joining member 30 will be described later. The distance from the first opposing surface 41a to the first surface 21a is, for example, 10 μm or more and 100 μm or less. The first opposing surface 41a is exposed from the sealing portion 60.

Refer to Figures 2 and 4. The first opposite surface 41b is the upper surface of the first chip substrate 41, and is entirely in contact with the sealing portion 60. The first side surface 41c shown in Figure 2 has a portion located outside the first opening 31 formed in the joining member 30 in a planar perspective view. From another perspective, it can be said that the first chip 40 (first side surface 41c) has a portion overlapping the solid portion 33 of the joining member 30 in a planar perspective view of the first surface 21a.

Here, when focusing on the first side surface 41c and the first opening 31, the first side surface 41c may be entirely located outside the first opening 31, or 70% or more of the first side surface 41c may be entirely located outside the first opening 31, or 40% or more of the first side surface 41c may be entirely located outside the first opening 31, or 40% or less of the first side surface 41c may be entirely located outside the first opening 31. When the entire first side surface 41c is located outside the first opening 31, the first opening 31 is blocked by the first chip 40 in the planar perspective.

At least a portion of the first chip substrate 41, including the first opposing surface 41a, is made of a piezoelectric material. For example, the first chip substrate 41 may be entirely made of a piezoelectric material, or may not be entirely made of a piezoelectric material. Examples of a first chip substrate 41 that is not entirely made of a piezoelectric material include a substrate in which a plate-shaped piezoelectric material is attached to a first base portion 41d, which will be described later, and a substrate in which a piezoelectric film is formed on the surface of the first base portion 41d. The first chip substrate 41 shown in FIG. 4 has a structure in which a first piezoelectric portion 41e is fixed to a flat (including layered) first base portion 41d.

The first base portion 41d may be made of, for example, a semiconductor such as silicon, a ceramic such as aluminum oxide, or a single crystal material such as sapphire. The first base portion 41d may be made of, for example, only one substrate, or may be made of two or more substrates stacked together. In a first base portion 41d including two or more substrates, these substrates may be made of different materials. The linear expansion coefficient of the first base portion 41d may be, for example, 1 to 9 ppm/K, or 2 to 4 ppm/K.

The material of the first base portion 41d is arbitrary. For example, the material of the first base portion 41d may be selected so that the first base portion 41d has a desired Young's modulus. The Young's modulus of the first base portion 41d is, for example, 160 to 210 GPa.

The first piezoelectric part 41e shown in FIG. 4 has a flat plate shape (including a layer shape). The first piezoelectric part 41e is a member that generates an elastic wave on its surface when a signal is input to the first excitation electrode 42 (when a voltage is applied). The material of the first piezoelectric part 41e is, for example, quartz crystal, lead zirconate titanate, barium titanate, potassium niobate, lithium niobate, lithium tantalate, etc. The Young's modulus of the first piezoelectric part 41e is, for example, 210 to 250 GPa.

The linear expansion coefficient of the first piezoelectric part 41e may be, for example, greater than the linear expansion coefficient of the first base part 41d. The linear expansion coefficient of the first piezoelectric part 41e is, for example, 10 to 18 ppm/K. The linear expansion coefficient of the first piezoelectric part 41e may be different in each of the up-down, front-back, left-right and right directions. For example, the linear expansion coefficient in the up-down direction may be smaller than the linear expansion coefficient in the front-back and/or left-right directions, or may be greater than the linear expansion coefficient in the front-back and left-right directions. In one embodiment, the linear expansion coefficient of the first piezoelectric part 41e in the up-down direction may be 8 to 15 ppm/K, the linear expansion coefficient in the left-right direction may be 12 to 18 ppm/K, and the linear expansion coefficient in the front-back direction may be 10 to 16 ppm/K.

Figure 4 shows the first piezoelectric part 41e attached (fixed) to the entire lower surface of the first base part 41d. However, the first piezoelectric part 41e may be provided, for example, on only a portion of the lower surface of the first base part 41d. The first piezoelectric part 41e may be thinner than the first base part 41d, for example. The first piezoelectric part 41e may be fixed to the first base part 41d by an adhesive containing an organic material or an inorganic material, or may be fixed (bonded) directly to the first base part 41d.

The first excitation electrode 42 is, for example, an IDT electrode including two interdigitated comb-like (lattice-like) metal layers. The first excitation electrode 42 may be, for example, an electrode in one metal layer, or an electrode in two or more metal layers. The metal layers may be, for example, aluminum, copper, or an alloy thereof. The first excitation electrode 42 is connected to the first terminals 44A, 44B via the first connection portions 45A, 45B.

The first excitation electrode 42 shown in FIG. 4 has two first bus bars 42a, 42b that extend in a predetermined direction (e.g., the propagation direction of the elastic wave) and whose ends face a pair of first reflectors 43A, 43B, and first electrode fingers 42c, 42d that are perpendicular to the two first bus bars 42a, 42b.

The first electrode finger 42c extends from the first bus bar 42a toward the first bus bar 42b, and the first electrode finger 42d extends from the first bus bar 42b toward the first bus bar 42a. The first electrode finger 42c is connected only to the first bus bar 42a, and the first electrode finger 42d is connected only to the first bus bar 42b.

The number of first electrode fingers 42c, 42d is arbitrary. The first electrode fingers 42c, 42d are arranged alternately so that they interdigitate with each other. The distance (pitch) between adjacent first electrode fingers 42c and 42d is arbitrary. By changing this distance (pitch), the frequency of the elastic wave propagating through the first piezoelectric portion 41e can be changed. An elastic wave with a half-wavelength of the distance between the first electrode fingers 42c and 42d propagates through the first piezoelectric portion 41e. The distance between adjacent first electrode fingers 42c and 42d may be set appropriately so that an elastic wave at a desired frequency is generated.

The first reflectors 43A and 43B can reflect the elastic waves propagating from the first excitation electrode 42 toward the first excitation electrode 42. The first reflectors 43A and 43B are located on the lower surface of the first piezoelectric portion 41e together with the first excitation electrode 42 and face the base 20. However, the first excitation electrode 42 and the first reflectors 43A and 43B may each be covered by an insulating protective film together with the first connection portions 45A and 45B, for example.

The first reflectors 43A and 43B shown in FIG. 4 each have two first bus bars 43a and 43b extending in a predetermined direction (the direction in which the elastic wave propagates) and a first strip electrode 43c that is perpendicular to the two first bus bars 43a and 43b and connected to the two first bus bars 43a and 43b. Each of the first reflectors 43A and 43B is provided with a plurality of first strip electrodes 43c.

See also FIG. 2. The first excitation electrode 42 and the pair of first reflectors 43A, 43B are located inside the first opening 31 in a planar perspective view. This means that the first excitation electrode 42 and the first reflectors 43A, 43B are located in the space between the first chip substrate 41 and the base 20 (first region Re1, described below). As a result, propagation of elastic waves in the first piezoelectric portion 41e is facilitated.

Refer only to FIG. 4. FIG. 4 shows a first chip 40 having only one first excitation electrode 42 and one pair of first reflectors 43A, 43B. However, the first chip 40 may have multiple first excitation electrodes 42 and pairs of first reflectors 43A, 43B. Furthermore, a ladder type filter or a multimode type filter may be formed by multiple first excitation electrodes 42. The same applies to the second chip 50 described later.

(Second chip)
The description of the first chip may be used in the description of the second chip 50. In this case, the first chip substrate 41 can be read as the second chip substrate 51, the first excitation electrode 42 as the second excitation electrode 52, the first reflectors 43A and 43B as the second reflectors 53A and 53B, the first terminals 44A and 44B as the second terminals 54A and 54B, and the first connection portions 45A and 45B as the second connection portions 55A and 55B. The first bus bars 42a and 42b and the first electrode fingers 42c and 42d constituting the first excitation electrode 42 can be read as the second bus bars 52a and 52b and the second electrode fingers 52c and 52d. Furthermore, the first bus bars 43a and 43b and the first strip electrode 43c constituting the first reflectors 43A and 43B can be read as the second bus bars 53a and 53b and the second strip electrode 53c. The second chip 50 will be described below, but parts common to the first chip 40 will be omitted.

Refer to FIG. 2. The second chip 50 is located above the second opening 32 formed in the joining member 30, faces the first surface 21a through the second opening 32, and is joined to the second pads 22C and 22D. The second chip 50 is joined to the second pads 22C and 22D through the bumps 3C and 3D (second bumps 3C and 3D described below).

2 has a portion located outside the second opening 32 formed in the joining member 30 in planar perspective. From another perspective, it can be said that the second chip 50 (second side 51c) has a portion overlapping the solid portion 33 of the joining member 30 in planar perspective of the first surface 21a. The proportion of the second side 51c located outside the second opening 32 in planar perspective may be the same as or different from the proportion of the first side 41c located outside the first opening 31 in planar perspective.

(Relationship between the first chip and the second chip)
The shape and dimensions of the first chip 40 and the shape and dimensions of the second chip 50 may be the same as or different from each other.

In one embodiment, the first chip 40 and the second chip 50 may be electrically connected via the external terminal 23. By connecting the first chip 40 and the second chip 50 via the external terminal 23, the electronic device 1 can form, for example, a splitter (e.g., a duplexer). For example, the first chip 40 may be a filter that passes only electrical signals having a frequency in the transmission passband, and the second chip 50 may be a filter that passes only electrical signals having a frequency in the reception passband. Note that the transmission communication band and the reception communication band do not overlap with each other.

The first chip 40 and the second chip 50 are electrically connected to the first pads 22A, 22B and the second pads 22C, 22D via bumps 3A to 3D, respectively. Hereinafter, the bumps 3A, 3B connecting the first chip 40 and the first pads 22A, 22B will be referred to as the first bumps 3A, 3B, and the bumps 3C, 3D connecting the second chip 50 and the second pads 22C, 22D will be referred to as the second bumps 3C, 3D.

(First bump)
2 and 3. The first bumps 3A and 3B are located between the base 20 and the first chip 40, and electrically connect the first pads 22A and 22B to the first terminals 44A and 44B. The heights of the first bumps 3A and 3B (the distances from the first pads 22A and 22B to the first terminals 44A and 44B) are smaller than the thickness of the bonding member 30, for example. The heights of the first bumps 3A and 3B may be, for example, 1 time or less, 4/5 times or less, 3/5 times or less, 2/5 times or less, or 1/5 times or less of the thickness of the bonding member 30. The first bumps 3A and 3B shown in FIG. 2 are entirely located inside the first opening 31, and are surrounded by the inner wall 31a of the first opening 31.

The size and shape of the first bumps 3A, 3B are arbitrary. For example, the first bumps 3A, 3B may be larger than the first pads 22A, 22B and/or the first terminals 44A, 44B in a cross section along the horizontal direction, or may be smaller than the first pads 22A, 22B and the first terminals 44A, 44B. Furthermore, the first bumps 3A, 3B may have a rectangular shape, a circular shape, or an elliptical shape in a cross section along the horizontal direction.

The first bumps 3A and 3B are, for example, solder. The solder may be solder containing lead or solder not containing lead. An example of solder containing lead is Pb-Sn alloy solder. An example of solder not containing lead is Au-Sn alloy solder, Au-Ge alloy solder, Sn-Ag alloy solder, Sn-Cu alloy solder, etc. The first bumps 3A and 3B may be a conductive adhesive material made by mixing a conductive filler into a thermosetting resin or the like.

The linear expansion coefficient of the first bumps 3A and 3B may be set, for example, in the range of 18 to 25 ppm/K, or in the range of 20 to 23 PPm/K. For example, the linear expansion coefficient of the first bumps 3A and 3B is greater than the linear expansion coefficient of the bonding member 30. In other words, it can be said that the first bumps 3A and 3B are surrounded by the bonding member 30, which has a smaller linear expansion coefficient than the first bumps 3A and 3B. The linear expansion coefficient of the first bumps 3A and 3B may be greater than the linear expansion coefficient of the first piezoelectric portion 41e, for example. The linear expansion coefficient of the first bumps 3A and 3B may be greater than the linear expansion coefficient of the sealing portion 60, or may be smaller than the linear expansion coefficient of the sealing portion 60.

(Second bump)
See Fig. 2. For example, the first bumps 3A and 3B can be used as the second bumps 3C and 3D. The second bumps 3C and 3D will be described below, but the parts common to the first bumps 3A and 3B will be omitted. The second bumps 3C and 3D are located between the base 20 and the second chip 50, and electrically connect the second pads 22C and 22D and the second terminals 54A and 54B. The second bumps 3C and 3D may be higher than the first bumps 3A and 3B, lower than the first bumps 3A and 3B, or may have the same height as the first bumps 3A and 3B.

The second bumps 3C and 3D shown in FIG. 2 are entirely located inside the second opening 32 and are surrounded by the inner wall 32a of the second opening 32. The second bumps 3C and 3D do not have any portion located outside the second opening 32 formed in the joining member 30. The explanation for the height of the first opening 31 can be used to explain the height of the second opening 32.

(Sealing part)
2 covers the upper surfaces and outer peripheral surfaces of the first chip 40 and the second chip 50 so that the lower surfaces of the first chip 40 and the second chip 50 are exposed. The sealing portion 60 covers the entire first chip 40 and the second chip 50 together with the base structure 10.

The linear expansion coefficient of the sealing portion 60 can be set arbitrarily. For example, the linear expansion coefficient of the sealing portion 60 may be 6 to 80 ppm/K. The linear expansion coefficient of the sealing portion 60 may be different in the horizontal direction (front/back/left/right direction) and the vertical direction. For example, the linear expansion coefficient in the horizontal direction may be 6 to 30 ppm/K, and the linear expansion coefficient in the vertical direction may be 20 to 80 ppm/K. The linear expansion coefficient of the sealing portion 60 may be greater than the linear expansion coefficient of the joining member 30. More specifically, the linear expansion coefficient of the sealing portion 60 in the horizontal and vertical directions may be greater than the linear expansion coefficient of the joining member 30 in the horizontal and/or vertical directions.

The glass transition temperature of the sealing portion 60 is set lower than the glass transition temperature of the joining member 30. In other words, the glass transition temperature of the joining member 30 is higher than the glass transition temperature of the sealing portion 60. For this reason, it can be said that the joining member 30 is less likely to become glassy (less likely to become soft) even when heat is applied compared to the sealing portion 60.

The glass transition temperature of the sealing portion 60 may be set, for example, within the range of 110 to 200°C. For example, under the condition that the glass transition temperature of the sealing portion 60 is set lower than the glass transition temperature of the joining member 30, the difference between the glass transition temperature of the sealing portion 60 and the joining member 30 may be set to 140°C or less, the difference between the glass transition temperature of the sealing portion 60 and the joining member 30 may be set to 90°C or less, the difference between the glass transition temperature of the sealing portion 60 and the joining member 30 may be set to 70°C or less, or the difference between the glass transition temperature of the sealing portion 60 and the joining member 30 may be set to 40°C or less.

The material of the sealing portion 60 may be, for example, an organic material. Examples of organic materials include resins (thermosetting resins). Examples of thermosetting resins include epoxy resins, phenolic resins, melamine resins, bismaleimide triazine resins, urea resins, and unsaturated polyester resins. To repeat, the glass transition temperature of the sealing portion 60 is lower than the glass transition temperature of the joining member 30. Under such conditions, the material of the sealing portion 60 is selected. The Young's modulus of the sealing portion 60 may be, for example, in the range of 0.05 to 17 GPa. Furthermore, the Young's modulus of the sealing portion 60 may vary depending on the temperature. For example, the Young's modulus of the sealing portion 60 may be 10 to 20 GPa at room temperature (for example, 15 to 30°C) and 1.5 GPa or less at high temperatures (for example, 220°C to 270°C). The Young's modulus of the sealing portion 60 may be smaller than the Young's modulus of the joining member 30. The material of the sealing portion 60 may be the same as the material of the base material 35, or may be different from the material of the base material 35. The sealing portion 60 may contain a filler.

The sealing portion 60 shown in FIG. 2 has a lower surface portion 61 joined to the base structure 10 (joint member 30), an upper surface portion 62 located on the opposite side of the lower surface portion 61, a side portion 63 connecting the lower surface portion 61 and the upper surface portion 62, a first recess 64 recessed from the lower surface portion 61 toward the upper surface portion 62 and having the first chip 40 located therein, a second recess 65 recessed from the lower surface portion 61 toward the upper surface portion 62 and having the second chip 50 located therein, a first extension portion 66 (see FIG. 3) extending from the inner surface of the first recess 64 along the joint member 30, and a second extension portion 67 extending from the inner surface of the second recess 65 along the joint member 30.

2, the entire lower surface portion 61 is joined to the joining member 30. The depths of the first recess 64 and the second recess 65 are each arbitrary. The depth of the first recess 64 may be the same as the thickness of the first chip 40, or may be smaller than the thickness of the first chip 40. In FIG. 2, the inner surface of the first recess 64 abuts against the side surface 41c of the first chip 40. However, the inner surface of the first recess 64 may be separated from the side surface 41c of the first chip 40. On the other hand, the depth of the second recess 65 may be the same as the thickness of the second chip 50, or may be smaller than the thickness of the second chip 50. In FIG. 2, the inner surface of the second recess 65 abuts against the side surface 51c of the second chip 50. However, the inner surface of the second recess 65 may be separated from the side surface 51c of the second chip 50.

The first extension 66 shown in FIG. 3 extends from the inner surface of the first recess 64 along the surface of the joining member 30 to the inner wall 31a of the first opening 31 opened in the joining member 30. The first extension 66 is joined to the upper surface of the joining member 30 and the inner wall 31a of the first opening 31 opened in the joining member 30. However, the first extension 66 may not extend to the inner wall 31a of the first opening 31 opened in the joining member 30 and may be joined only to the upper surface of the joining member 30. The thickness of the first extension 66 along the surface of the joining member 30 may be, for example, 1 μm or less or 1 μm or more.

The description of the first extension 66 can be used to describe the second extension 67 shown in FIG. 2. The second extension 67 may extend along the surface of the joining member 30 to the inner wall 32a of the second opening 32, or may not extend to the inner wall 32a of the second opening 32. The thickness of the second extension 67 along the surface of the joining member 30 may be, for example, 1 μm or less, or 1 μm or more.

(region)
The electronic device 1 is provided with a first region Re1 for accommodating the first bumps 3A and 3B, and a second region Re2 for accommodating the second bumps 3C and 3D. The first region Re1 is an area surrounded by the first chip 40 (first opposing surface 41a), the bonding member 30 (inner wall 31a), and the base body 20 (first surface 21a). On the other hand, the second region Re2 is an area surrounded by the second chip 50 (second opposing surface 51a), the bonding member 30 (inner wall 32a), and the base body 20 (first surface 21a). The height of the first region Re1 may be the same as the thickness of the bonding member 30, or may be slightly larger than the thickness of the bonding member 30 (by the thickness of the first extension portion 66). The same applies to the height of the second region Re2. The first region Re1 and the second region Re2 may be in a vacuum state or may be filled with a predetermined gas (for example, nitrogen). This reduces direct exposure of the first bumps 3A, 3B and the second bumps 3C, 3D to the outside, thereby improving the durability of the electronic device 1.

Next, we will explain the manufacturing method of electronic devices.

Refer to FIG. 5. FIG. 5 shows a diagram for explaining a method for manufacturing an electronic device 1 according to one example. Refer to FIG. 5A only. As shown in FIG. 5A, a base structure 10 is prepared in which a bonding member 30 is layered on the base 20. The bonding member 30 may be in a semi-cured (uncured) state or in a cured state. Furthermore, the bonding member 30 may be in a state where it is bonded to the base 20 or in a state where it is not bonded to the base 20. The bonding member 30 can be created by opening through holes (first opening 31 and second opening 32) by laser or punching, etc. in a sheet-like member containing a cloth such as glass cloth inside.

Refer to Figures 5A and 5B. After the base structure 10 is prepared, for example, the first bumps 3A, 3B and the second bumps 3C, 3D are formed on the base structure 10. Specifically, the first bumps 3A, 3B are bonded to the first pads 22A, 22B, and the second bumps 3C, 3D are bonded to the second pads 22C, 22D. Next, a mounting body 2 including a first chip 40 and a second chip 50 is prepared, and the mounting body 2 is mounted on the base structure 10. The mounting body 2 is mounted on the base structure 10 by connecting the first and second terminals 44A, 44B, 54A, 54B to the first and second bumps 3A to 3D and bonding the sealing portion 60 to the bonding member 30.

Refer only to FIG. 5B. In one embodiment, the sealing portion 60 can be joined to the joining member 30 by abutting the sealing portion 60 against the upper surface of the joining member 30 in an uncured state and curing the joining member 30. In one embodiment, the sealing portion 60 can be joined to the joining member 30 by abutting the sealing portion 60 against the upper surface of the joining member 30 in a cured state, melting it, and then curing it again.

5A and 5B, a method of directly bonding the mounting body 2 including the first chip 40 and the second chip 50 to the base structure 10 has been described. However, the bonding of the mounting body 2 to the base structure 10 is not limited to the above method. For example, after bonding the first and second chips 40, 50 to the first and second pads 22A to 22D, the mounting body 2 may be mounted on the base structure 10 by forming a sealing portion 60 covering the first and second chips 40, 50 on the upper surface of the bonding member 30. In one embodiment, the method of forming the sealing portion 60 includes, for example, a method of supplying resin (uncured) to the upper surface of the base structure 10 (bonding member 30) so as to cover the first chip 40 and the second chip 50 mounted on the base structure 10, and curing the resin to form the sealing portion 60. In one embodiment, the method of forming the sealing portion 60 includes a method of placing a sheet-like resin (uncured) on the upper surface of the joining member 30 so as to cover the first chip 40 and the second chip 50 mounted on the base structure 10, and curing the resin by applying pressure and heat to form the sealing portion 60 bonded to the joining member 30. In one embodiment, the method of forming the sealing portion 60 includes a method of supplying molten resin to the upper surface of the joining member 30 by screen printing or a dispenser so as to cover the first chip 40 and the second chip 50 mounted on the base structure 10, and curing the resin to form the sealing portion 60 bonded to the base structure 10. Note that powdered resin may be used instead of the uncured resin.

See also FIG. 5C. In forming the sealing portion 60, for example, a part of the sealing portion 60 (hereinafter, sometimes referred to as "resin") may melt and flow onto the upper surface of the joining member 30. The molten resin may flow along the upper surface of the joining member 30 and may flow into the inside of the first opening 31 and/or the second opening 32 opened in the joining member 30. The resin supplied to the upper surface of the joining member 30 is then cured, so that the resin that has flowed into the inside of the first opening 31 and/or the second opening 32 is cured. At this time, the resin that has flowed into the inside of the first opening 31 and/or the second opening 32 is bonded to the inner wall 31a and/or the inner wall 32a.

Refer to Figures 5A to 5C. Figures 5A to 5C show a method for bonding one mounting body 2 to one base structure 10. However, for example, multiple mounting bodies 2 (in a wafer-like or individualized state) may be bonded simultaneously to a wafer including multiple arranged base structures 10.

Refer to Figures 2 and 3. The glass transition temperature of the joining member 30 is higher than the glass transition temperature of the sealing portion 60. As a result, the joining member 30 is prevented from becoming glassy (softening) more easily than the sealing portion 60 even when heat is applied to the electronic device 1. Therefore, the joining member 30 is less likely to become glassy and can maintain a hard state even when heat is applied. Since the sealing portion 60 is joined to the joining member 30, which can maintain this hard state, a force is applied to the sealing portion 60 in the opposite direction to the direction of thermal expansion by the joining member 30. This reduces the thermal expansion of the sealing portion 60 via the joining member 30. As a result, a durable electronic device 1 can be provided.

The linear expansion coefficient of the joining member 30 is smaller than that of the sealing portion 60. As a result, the amount of thermal expansion (volume) of the joining member 30 is smaller than that of the sealing portion 60 even when heat is applied to the electronic device 1. Because the sealing portion 60 is joined to the joining member 30, which has small thermal expansion, a force is applied to the sealing portion 60 in the opposite direction to the direction of thermal expansion attempted by the joining member 30. This reduces the thermal expansion of the sealing portion 60 via the joining member 30. As a result, a more durable electronic device 1 can be provided.

The linear expansion coefficient of the joining member 30 is smaller than that of the base 20. Furthermore, the glass transition temperature of the joining member 30 is higher than that of the base 20. Since the linear expansion coefficient of the joining member 30 is smaller than that of the base 20, the joining member 30 expands less than the base 20 when heat is applied. Since the glass transition temperature of the joining member 30 is higher than that of the base 20, the joining member 30 is prevented from becoming glassy more easily than the base 20. Since the base 20 is joined to the joining member 30, which has a small thermal expansion and a high glass transition temperature, the thermal expansion of the base 20 is reduced via the joining member 30. Therefore, a more durable electronic device 1 can be provided.

The first opposing surface 41a is exposed from the sealing portion 60. By exposing the first opposing surface 41a from the sealing portion 60, the electrical connection between the first chip 40 and the first pads 22A and 22B can be made favorable in the first chip 40 whose outer peripheral surface is covered.

In a planar perspective of the first surface 21a, the first chip 40 has a portion located outside the first opening 31 opened in the joining member 30. As a result, even if the first chip 40 is enlarged, it is not necessary to enlarge the first opening 31 so that the first chip 40 is located inside the first opening 31 in a planar perspective of the first surface 21a. As a result, the reduction in the volume of the joining member 30 (solid portion 33) can be reduced. Therefore, a durable electronic device 1 can be provided.

The sealing portion 60 has a portion that is bonded to the inner wall 31a of the first opening 31 formed in the joining member 30. Since the sealing portion 60 has a portion that is bonded to the inner wall 31a of the first opening 31, the sealing portion 60 is more strongly bonded to the joining member 30. As a result, a durable electronic device 1 can be provided.

The joining member 30 has a reinforcing material 34 and a base material 35 impregnated in the reinforcing material 34. By having the reinforcing material 34 in the joining member 30, the strength of the joining member 30 is improved compared to when the reinforcing material 34 is only the base material 35. As a result, a durable electronic device 1 can be provided.

By increasing the strength of the bonding member 30, it is possible to enlarge the first opening 31 formed in the bonding member 30 while ensuring the strength of the electronic device 1. This improves the degree of freedom in the arrangement positions of the first pads 22A, 22B located inside the first opening 31. This improves the degree of freedom in the design of the first chip 40.
In addition, the first bumps 3A and 3B can be partially surrounded by the strong bonding member 30, which reduces the load applied to the first bumps 3A and 3B. As a result, a durable electronic device 1 can be provided.

The reinforcing material 34 is glass cloth. By using glass cloth as the reinforcing material 34, the strength of the joining member 30 can be further improved. As a result, a more durable electronic device 1 can be provided.

The bonding member 30 has a second opening 32 at the location where the second pads 22C and 22D are located. Furthermore, the second chip 50 is connected to the second pads 22C and 22D via the second opening 32. Since the second opening 32 is provided at the location where the second pads 22C and 22D are located, it is not necessary to position all of the first pads 22A and 22B and the second pads 22C and 22D inside the first opening 31. This eliminates the need to enlarge only the first opening 31. As a result, the reduction in the volume of the bonding member 30 can be reduced. Therefore, a durable electronic device 1 can be provided.

Next, we will explain the electronic device in the first modified example.

Refer to FIG. 6A. FIG. 6A shows an electronic device 101 according to a first modified example of the present disclosure. The same reference numerals are used for parts common to the electronic device 1 of the embodiment, and detailed descriptions are omitted.

(Joining member)
In the bonding member 130 shown in FIG. 6A, the first opening 131 and the second opening 132 are larger than the first chip 40 and the second chip 50 in a planar perspective of the first surface 21a. From another perspective, the inner wall 131a of the first opening 131 surrounds the first side surface 41c of the first chip 40, and the inner wall 132a of the second opening 132 surrounds the second side surface 51c of the second chip 50 in a planar perspective of the first surface 21a. From another perspective, it can be said that the solid portion 33 of the bonding member 130 does not have a portion overlapping the first chip 40 and the second chip 50 in a planar perspective of the first surface 21a. This allows the bonding member 130 and the sealing portion 60 to be bonded more strongly. As a result, a durable electronic device 101 can be provided.

Next, we will explain the electronic device in the second modified example.

Refer to FIG. 6B. FIG. 6B shows an electronic device 201 according to a second modified example of the present disclosure. The same reference numerals are used for parts common to the electronic device 1 of the embodiment, and detailed descriptions are omitted.

(Joining member)
In the bonding member 230 shown in FIG. 6B, in a planar perspective of the first surface 21a, the first opening 231 and the second opening 232 have the same size as the first chip 40 and the second chip 50. From another perspective, in a planar perspective of the first surface 21a, the side surface (first side surface 41c) of the first chip 40 entirely overlaps the inner wall 231a of the first opening 231, and the second side surface 51c of the second chip 50 entirely overlaps the inner wall 232a of the second opening 232. This makes it possible to ensure a sufficient area for bonding the sealing portion 60 to the bonding member 230 in a planar perspective. As a result, a durable electronic device 201 can be provided. In addition, in a planar perspective of the first surface 21a, for example, the sealing portion 60 is less likely to be located between the first chip 40 and the inner wall 231a of the first opening 231, so that the region Re1 in which the first bumps 3A, 3B and the first pads 22A, 22B are located can be sufficiently secured. This improves the degree of freedom in designing the first chip 40. Note that, in a planar perspective of the first surface 21a, the overlapping of the side surfaces of the first chip 40 and the second chip 50 with the inner walls 231a, 232a of the first opening 231 and the second opening 232 refers to a case in which the respective deviations are 10 μm or less.

Next, we will explain the electronic device in the third modified example.

Refer to FIG. 7. FIG. 7 shows an electronic device 301 according to a third modified example of the present disclosure. The same reference numerals are used for parts common to the electronic device 1 of the embodiment, and detailed descriptions are omitted.

The base 320 shown in FIG. 6 has a ceramic base body 321, a number of pads 22A-22D located on the upper surface 21a of the base body 321, a number of external terminals 23A-23F (see FIG. 1) located on the lower surface 21b of the base body 321, and an internal conductor 24 that connects the pads 22A-22D and the external terminals 23A-23F and is located inside the base body 321.

The linear expansion coefficient of the base 320 may be, for example, 4 to 12 ppm/K, or 5 to 10 ppm/K. For example, the linear expansion coefficient of the base 320 may be greater than the linear expansion coefficient of the joining member 30. The Young's modulus of the base 320 may be, for example, 250 to 420 GPa, or 280 to 350 GPa.

The substrate structure and electronic device in this disclosure are not limited to the embodiments and modifications described above, and may be implemented in various forms. Below, we introduce some examples of substrate structures and electronic devices with modified forms.

In the embodiment, an example of a joining member composed only of a reinforcing material and a base material has been described. However, the joining member may contain fillers and the like in addition to these. Also, in the joining member 30, an example in which a base material is impregnated into one cloth (glass cloth) has been described. However, the joining member may be a member in which a plurality of cloths (glass cloths) are laminated and impregnated with the base material. Furthermore, the joining member may be composed only of a resin that does not contain glass cloth, or may be composed of a resin containing a filler inside.

In the embodiment, an example of a joining member having a first opening and a second opening has been described. However, the joining member may have only one opening, or may have three or more openings. In planar perspective, two or more openings may be provided that overlap only one chip, or only one opening may be provided that overlaps two chips. The number of openings may be changed as appropriate.

In the present embodiment, an example has been described in which an electronic device includes two acoustic wave chips. However, the number of acoustic wave chips included in an electronic device may be only one, or may be three or more. Furthermore, in the embodiment, an acoustic wave chip in which the first chip and the second chip are one-port resonators has been described. However, the first chip and/or the second chip may be two-port resonators. In other words, the first chip and the second chip do not necessarily have to be the same acoustic wave chip. Furthermore, the electronic device in the present disclosure may include electronic components (electronic elements) other than acoustic waves.

In the embodiment, an example has been described in which the sealing portion has a first extension portion and a second extension portion that extend along the surface of the base body. However, the first extension portion and the second extension portion are not essential components of the sealing portion. If necessary, the first extension portion and/or the second extension portion can be eliminated. The sealing portion may cover only the outer peripheral surface (side surface) of the first chip and/or the second chip.

REFERENCE SIGNS LIST 1, 101, 201, 301...electronic device 3A, 3B...first bump 3C, 3D...second bump 10, 110, 210, 310...base structure 20, 320...base 21a...first surface 22A, 22B...first pad 22C, 22D...second pad 30, 130, 230...joining member 30a, 130a, 230a...first opening 30b, 130b, 230b...second opening 31a, 131a, 231a...inner wall 32a, 132a, 232a...inner wall 40...first chip 50...second chip 60...sealing portion

Claims (3)

a substrate having a first surface;
a joining member joined to the first surface and having a first opening;
a first chip facing the first surface through the first opening;
having
The linear expansion coefficient of the bonding member is smaller than the linear expansion coefficient of the base body,
The joining member has a glass transition temperature higher than a glass transition temperature of the substrate. a substrate having a first surface;
a joining member joined to the first surface and having a first opening;
a first chip bonded to the substrate by bumps in the first opening;
a sealing portion that covers the first chip and the base;
having
the bonding member is located between the base and the first chip,
The linear expansion coefficient of the joining member is smaller than the linear expansion coefficient of the sealing portion.
Electronic devices. a substrate having a first surface;
a joining member joined to the first surface and having a first opening;
a first chip bonded to the substrate by bumps in the first opening;
a sealing portion that covers the first chip and the base;
having
the bonding member is located between the base and the first chip,
The glass transition temperature of the bonding member is higher than the glass transition temperature of the sealing portion.
Electronic devices.

Images