CN114499437A - Electronic component and elastic wave device - Google Patents

Electronic component and elastic wave device Download PDF

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Publication number
CN114499437A
CN114499437A CN202110868105.9A CN202110868105A CN114499437A CN 114499437 A CN114499437 A CN 114499437A CN 202110868105 A CN202110868105 A CN 202110868105A CN 114499437 A CN114499437 A CN 114499437A
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CN
China
Prior art keywords
substrate
elastic wave
bump
wave device
recess
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Pending
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CN202110868105.9A
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Chinese (zh)
Inventor
笹冈康平
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Sanyan Japan Technology Co ltd
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Sanyan Japan Technology Co ltd
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Publication date
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Publication of CN114499437A publication Critical patent/CN114499437A/en
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02535—Details of surface acoustic wave devices
    • H03H9/02543—Characteristics of substrate, e.g. cutting angles
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02535—Details of surface acoustic wave devices
    • H03H9/02614—Treatment of substrates, e.g. curved, spherical, cylindrical substrates ensuring closed round-about circuits for the acoustical waves
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02535—Details of surface acoustic wave devices
    • H03H9/02637—Details concerning reflective or coupling arrays
    • H03H9/02653—Grooves or arrays buried in the substrate
    • H03H9/02661—Grooves or arrays buried in the substrate being located inside the interdigital transducers

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
  • Semiconductor Integrated Circuits (AREA)

Abstract

An electronic component comprising a wiring substrate, a functional element substrate arranged on the wiring substrate so as to face the wiring substrate, a functional element provided on the functional element substrate, a bump pad electrically connected to the functional element provided on the functional element substrate, and a bump electrically connected to the bump pad and the wiring substrate, wherein a recess is formed in the functional element substrate in a region where the bump pad is formed, whereby a miniaturized and thinned electronic component can be provided.

Description

Electronic component and elastic wave device
Technical Field
The present invention relates to an electronic component, and an elastic wave device.
Background
High functionality of smart phones and the like, which represent mobile communication terminals, is being developed year by year. Therefore, the number of electronic components used therein also tends to increase. On the other hand, since it is a mobile communication terminal, miniaturization and thinning are required. Therefore, electronic components used in mobile communication terminals and acoustic wave devices as examples of the electronic components are also required to be miniaturized and thinned.
Patent document 1 (japanese patent laid-open No. 2020-53812) discloses an example of a technique relating to a miniaturized elastic wave device.
However, further miniaturization and thinning are still required for conventional electronic components and elastic wave devices as examples of the electronic components. In addition, in the structure of the acoustic wave device substrate, a support substrate such as sapphire bonded to the piezoelectric substrate is expensive, and therefore, the acoustic wave device substrate itself is also reduced in size to reduce the cost.
Disclosure of Invention
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a miniaturized and thin electronic module and an acoustic wave device.
In order to solve the technical problem, an electronic component of the present invention includes:
a wiring substrate;
a functional element substrate disposed on the wiring substrate so as to face the wiring substrate;
a functional element provided on the functional element substrate;
a bump pad electrically connected to a functional element disposed on the functional element substrate; and a bump electrically connected to the bump pad and the wiring substrate,
wherein a recess is formed on the functional element substrate in a region where the bump pad is formed.
In one aspect of the present invention, the bump is formed only in a region where the recess is formed.
In an aspect of the present invention, the bump pad covers the concave portion.
In one aspect of the present invention, the bump pad is provided only in a region where the recess is formed.
In one aspect of the present invention, the recess is formed in a substantially circular shape or a substantially elliptical shape.
In one aspect of the present invention, the recess is formed at an end portion of the functional element substrate.
In one aspect of the present invention, the wiring substrate is formed with a recess, and the bump is electrically connected to the wiring substrate in a region where the recess is formed on the wiring substrate.
The elastic wave device of the present invention is formed by the above-described electronic component, wherein the functional element substrate is an elastic wave element substrate, and the functional element is an elastic wave element.
In one aspect of the present invention, the elastic wave element substrate includes a piezoelectric substrate and a support substrate, and the support substrate is a substrate made of sapphire, alumina, spinel, or silicon.
In one aspect of the present invention, the elastic wave element is formed of an interdigital transducer that excites a surface acoustic wave.
In one aspect of the present invention, the elastic wave element is formed of a piezoelectric thin film resonator.
The invention has the beneficial effects that: according to the present invention, a miniaturized and thin electronic component and an elastic wave device can be provided.
Drawings
Fig. 1 is a sectional view showing an elastic wave device as an electronic component of the first embodiment.
Fig. 2 is a diagram showing the structure of an elastic wave device substrate.
Fig. 3 is a plan view illustrating that the acoustic wave device is a surface acoustic wave resonator.
Fig. 4 is a sectional view illustrating that the elastic wave device is a piezoelectric thin film resonator.
Fig. 5(a) is a diagram illustrating a bump pad and a bump of an acoustic wave device substrate in a conventional acoustic wave device.
Fig. 5(b) is a diagram showing the bump expansion in fig. 5(a) after flip chip bonding.
Fig. 6(a) is a diagram illustrating a bump pad and a bump of an acoustic wave device substrate of an acoustic wave device according to the present invention.
Fig. 6(b) is a diagram showing the expansion of the bump in fig. 6(a) after flip chip bonding.
Fig. 7 is a sectional view showing an elastic wave device according to a second embodiment of the present invention.
Fig. 8 is a sectional view showing an elastic wave device according to a third embodiment of the present invention.
Detailed Description
The following describes embodiments of the present invention with reference to the drawings.
(first embodiment)
Fig. 1 is a sectional view of an electronic component of the first embodiment, that is, an elastic wave device 1.
As shown in fig. 1, acoustic wave device 1 of the present embodiment includes wiring board 3 and acoustic wave device substrate 5 as a functional device substrate mounted on wiring board 3.
The wiring substrate 3 is, for example, a multilayer substrate formed of resin, or a Low Temperature Co-fired ceramic (LTCC) multilayer substrate composed of a plurality of dielectric layers. The wiring substrate 3 includes a plurality of external connection terminals 31.
As the elastic wave device substrate 5, for example, a piezoelectric single crystal such as lithium tantalate, lithium niobate, or quartz, or a substrate formed using piezoelectric ceramics can be used.
In addition, a substrate in which a piezoelectric substrate and a supporting substrate are bonded may be used as elastic wave device substrate 5. The support substrate may be, for example, a sapphire substrate, an alumina substrate, a spinel substrate, or a silicon substrate.
The acoustic wave device substrate 5 is mounted on the wiring substrate 3 by flip-chip bonding (flip-chip bonding) via the bumps 15.
The bump 15 may be a gold bump, for example. The height of the bump 15 is, for example, 20 μm to 50 μm.
In the region where the bump 15 is formed on the acoustic wave device substrate 5, the recess 7 and the bump pad 9 are formed. Although not shown in fig. 1, the elastic wave device substrate 5 has formed thereon an elastic wave device and a wiring pattern for electrically connecting the elastic wave device and the bump pads 9. The bump pad 9 may be formed only in the region of the recess 7, or may include a region other than the recess 7 so as to cover the recess 7.
The recess 7 may be formed by dry etching (dry etching) or wet etching (wet etching) using photolithography (photolithography). Further, the metal layer may be formed by laser processing or the like. The recess 7 is formed in advance in the region where the bump 15 is arranged. The recess 7 may be, for example, substantially circular or substantially oval. Further, the shape may be substantially quadrangular.
The depth of the recess 7 can be set to 0.5 μm to 2 μm, for example. The depth of the region where the recess 7 is formed is not necessarily uniform, and for example, may be formed to be deeper closer to the central portion of the recess 7 and gradually shallower toward the outward extending portion. With such a structure, disconnection of the wiring pattern electrically connecting the bump pads 9 and the elastic wave device can be prevented.
The depth of the concave portion 7 can be appropriately adjusted according to the thickness of the acoustic wave device substrate 5. In the case where a substrate in which a piezoelectric substrate and a support substrate are bonded is used as the elastic wave device substrate 5, the recess 7 may be formed so that the support substrate is exposed by completely removing a portion of the piezoelectric substrate.
The sealing portion 17 is formed so as to cover the acoustic wave device substrate 5. The closing portion 17 may be formed of an insulating material such as synthetic resin, or may be formed of metal. Examples of the synthetic resin include, but are not limited to, epoxy resin, polyimide, and the like. Preferably, the closing portion 17 is formed in a low temperature hardening process using an epoxy resin.
Fig. 2 is a diagram showing the structure of acoustic wave device substrate 5. As shown in fig. 2, bump pads 9, an acoustic wave device 52 as a functional device, and a wiring pattern 54 are formed on the acoustic wave device substrate 5. As shown by the dotted line, the bump pad 9 and a part of the wiring pattern 54 are formed in the region of the recess 7.
An insulator 56 is formed on the wiring pattern 54. The insulator 56 may be made of polyimide, for example. The insulator 56 may be formed as a thin film having a thickness of 1000nm, for example.
The wiring pattern 54 is also formed on the insulator 56, and wirings that intersect each other in a three-dimensional manner are formed through the insulator 56.
The bump pads 9, the elastic wave elements 52, and the wiring patterns 54 may be made of an appropriate metal such as silver, aluminum, copper, titanium, palladium, or an alloy of these metals. These metal patterns may be formed of a laminated metal film in which a plurality of metal layers are laminated. The thickness of the bump pad 9, the elastic wave element 52, and the wiring pattern 54 may be, for example, 150nm to 400 nm.
The bump pad 9 includes an input pad In, an output pad Out, and a ground pad GND. Further, the bump pads 9 and the wiring pattern 54 are electrically connected to the acoustic wave device 52.
As shown in fig. 2, by forming a plurality of elastic wave elements 52, a band pass filter, for example, can be formed. The band pass filter is designed such that only an electronic signal In a desired frequency band passes among electronic signals input from the input pad In.
An electronic signal inputted from the input pad In passes through the band pass filter, and only an electronic signal In a desired frequency band is outputted to the output pad Out.
The electronic signal output to the output pad Out is output to the external connection terminal 31 of the wiring substrate 3 via the bump 15.
Fig. 3 is a plan view illustrating that the acoustic wave element 52 is a surface acoustic wave resonator.
As shown in fig. 3, an IDT (inter digital Transducer) 52a and a reflector 52b for exciting a surface acoustic wave are formed on the elastic element substrate 5. The IDT52a has a pair of comb electrodes 52c facing each other. Each comb electrode 52c has a plurality of electrode fingers 52d and bus bars 52e respectively connected to the plurality of electrode fingers 52 d. Reflectors 52b are provided on both sides of the IDT52 a.
The IDT52a and the reflectors 52b are formed of an alloy of aluminum and copper, for example. The IDT52a and the reflector 52b are thin films having a thickness of 150nm to 400nm, for example. IDT52a and reflectors 52b may also contain other suitable metals such as titanium, palladium, and silver, alloys containing these metals, or alloys formed from these metals. The IDT52a and the reflectors 52b may be formed of a laminated metal film in which a plurality of metal layers are laminated.
Fig. 4 is a sectional view illustrating that elastic wave element 52 is a piezoelectric thin film resonator.
As shown in fig. 4, a piezoelectric film 62 is provided on the chip substrate 60. The lower electrode 64 and the upper electrode 66 are provided so as to sandwich the piezoelectric film 62. A gap 68 is formed between the lower electrode 64 and the chip substrate 60. The lower electrode 64 and the upper electrode 66 excite an elastic wave in a thickness longitudinal vibration mode in the piezoelectric film 62.
The chip substrate 60 may be a semiconductor substrate such as silicon, or an insulating substrate such as sapphire, alumina, spinel, or glass. For example, aluminum nitride may be used for the piezoelectric film 62. For the lower electrode 64 and the upper electrode 66, a metal such as ruthenium can be used.
Elastic wave element 52 may be a multimode filter or a ladder filter as appropriate to obtain a desired band-pass filter characteristic.
The effects of the present invention are explained herein. Before explaining the effects of the present invention, a conventional elastic wave device will be explained. Fig. 5(a) -5(b) are diagrams illustrating a BUMP PAD and a BUMP of an acoustic wave device substrate in a conventional acoustic wave device.
Fig. 5(a) is a diagram showing a conventional acoustic wave device in which a BUMP is formed on a BUMP PAD of an acoustic wave element substrate 5.
As shown in fig. 5(a), the bump PAD of the conventional elastic wave device is, for example, a substantially quadrangular shape having a long side of 130 μm and a short side of 110 μm. Further, the diameter of the BUMP is, for example, 60 μm. The reason why the diameter of the BUMP PAD is set larger than that of the BUMP is because the BUMP is expanded when the flip chip bonding is performed.
Ultrasonic waves are generated by vibration in the longitudinal direction, and pressure is applied to secure the bonding of the BUMP and the wiring substrate.
Fig. 5(b) is a diagram showing the BUMP expansion after flip chip bonding.
As shown in fig. 5(b), the BUMP after flip chip bonding is expanded to 100 μm in the long side direction of the BUMP PAD and expanded to 80 μm in the short side direction of the BUMP PAD.
Thus, when designing the BUMP PAD of the conventional elastic wave device, the expansion of the BUMP diameter during flip chip bonding and the manufacturing error must be considered.
Fig. 6(a) -6(b) are views illustrating bump pads 9 and bumps 15 of acoustic wave device substrate 5 of acoustic wave device 1 according to the present invention.
Fig. 6(a) shows a bump 15 formed on a bump pad 9 of an elastic wave device 1 according to the present invention.
As shown in fig. 6(a), the bump pad 9 is, for example, a substantially square having a side of 90 μm. In addition, in the region where the bump pad 9 is formed, a substantially circular recess 7 having a diameter of, for example, 80 μm is formed. The diameter of the bump 15 is, for example, 60 μm.
Fig. 6(b) is a diagram showing the expansion of the bump 15 after flip chip bonding.
As shown in fig. 6(b), after flip chip bonding, the bump 15 expands into a substantially circular shape having a diameter of approximately 80 μm. In other words, the bump 15 is still located within the area of the recess 7 even after flip chip bonding.
The electronic component of the present invention is described above by taking an elastic wave device as an example. Of course, the present invention is not limited to the elastic wave Device, and may be applied to an IPD (Integrated Passive Device) or the like, for example, and an electronic component having a functional element on a substrate and mounted on a wiring substrate in a flip-chip bonding manner.
According to the elastic wave device of the present invention, the bump can suppress the expansion of the flip chip during bonding, so that the elastic wave device substrate can be miniaturized. Further, the electronic component and the acoustic wave device can be miniaturized and thinned.
(second embodiment)
Fig. 7 is a sectional view showing elastic wave device 101 according to a second embodiment of the present invention.
As shown in fig. 7, elastic wave device 101 of the present embodiment includes wiring board 103 and elastic wave element substrate 105 mounted on wiring board 103.
The acoustic wave device substrate 105 has a recess 107 formed at an end thereof. The bumps 115 are formed to protrude from the epitaxial portion of the elastic wave device substrate 105 by pressure and vibration at the time of flip chip bonding.
Although the example in which the bumps 115 protrude from the extension portion of the acoustic wave device substrate 105 is shown in the present embodiment, the bumps 115 may not protrude from the extension portion of the acoustic wave device substrate 105 by adjusting the amount and height of the bumps 115, the vibration width during flip chip bonding, and the like.
The other structures are not repeated as described in the first embodiment.
(third embodiment)
Fig. 8 is a cross-sectional view showing elastic wave device 201 according to a third embodiment of the present invention.
As shown in fig. 8, acoustic wave device 201 of the present embodiment includes a wiring substrate 203 and an acoustic wave device substrate 205 mounted on wiring substrate 203.
A recess 207 is formed in the acoustic wave device substrate 205.
The wiring substrate 203 has a recess 2037 formed at a position corresponding to the recess 207. The bump 215 is electrically connected to the wiring substrate 203 in a region where the recess 2037 is formed on the wiring substrate 203. By providing the concave portion 2037 also on the wiring substrate 203, the bump 215 can be suppressed from spreading on the wiring substrate 203 side. Further, acoustic wave device 201 can also be made thinner.
The other structures are not repeated as described in the first embodiment or the second embodiment.
As described above, according to the present invention, it is possible to provide a further miniaturized and thin electronic component and an acoustic wave device.
It is needless to say that the present invention is not limited to the embodiments described above, and includes all embodiments that can achieve the object of the present invention.
Furthermore, while at least one embodiment has been described above, it is to be appreciated various alterations, modifications, or improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the scope of the invention. It is to be understood that the aspects of the method or apparatus described herein are not limited in their application to the details of construction and the arrangements of the components set forth in the above description or illustrated in the drawings. The methods and apparatus may be practiced in other embodiments or with other embodiments. The examples are given by way of illustration only and not by way of limitation. Furthermore, the descriptions and words used herein are for the purpose of illustration only and are not intended to be limiting. The use of "including," "comprising," "having," "containing," and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The use of the term "or any other term in the description using the term" or "may be interpreted to mean one, more than one, or all of the recited term. Front, back, left, right, top, bottom, up, down, and horizontal and vertical references are for convenience of description and do not limit the position and spatial configuration of any of the components of the present invention. Accordingly, the foregoing description and drawings are by way of example only.

Claims (11)

1. An electronic assembly, characterized by: the electronic component includes:
a wiring substrate;
a functional element substrate disposed on the wiring substrate so as to face the wiring substrate;
a functional element provided on the functional element substrate;
a bump pad electrically connected to a functional element disposed on the functional element substrate; and
a bump electrically connected to the bump pad and the wiring substrate,
wherein a recess is formed on the functional element substrate in a region where the bump pad is formed.
2. The electronic assembly of claim 1, wherein: the bump is formed only in a region where the recess is formed.
3. The electronic assembly of claim 1, wherein: the bump pad covers the recess.
4. The electronic assembly of claim 1, wherein: the bump pads are disposed only in a region where the recess is formed.
5. The electronic assembly of claim 1, wherein: the recess is formed in a substantially circular shape or a substantially elliptical shape.
6. The electronic assembly of claim 1, wherein: the recess is formed at an end of the functional element substrate.
7. The electronic assembly of claim 1, wherein: the wiring substrate is formed with a recess, and the bump is electrically connected to the wiring substrate in a region where the recess is formed on the wiring substrate.
8. An elastic wave device characterized by being constituted by the electronic component according to any one of claims 1 to 7, wherein the functional element substrate is an elastic wave element substrate, and the functional element is an elastic wave element.
9. The elastic wave device according to claim 8, wherein: the elastic wave element substrate includes a piezoelectric substrate and a support substrate, and the support substrate is a substrate made of sapphire, alumina, spinel, or silicon.
10. The elastic wave device according to claim 8, wherein: the elastic wave element is composed of an interdigital transducer for exciting a surface acoustic wave.
11. The elastic wave device according to claim 8, wherein: the elastic wave element is formed of a piezoelectric thin film resonator.
CN202110868105.9A 2020-10-28 2021-07-30 Electronic component and elastic wave device Pending CN114499437A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2020-180221 2020-10-28
JP2020180221A JP2022071324A (en) 2020-10-28 2020-10-28 Electronic component

Publications (1)

Publication Number Publication Date
CN114499437A true CN114499437A (en) 2022-05-13

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110868105.9A Pending CN114499437A (en) 2020-10-28 2021-07-30 Electronic component and elastic wave device

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JP (1) JP2022071324A (en)
CN (1) CN114499437A (en)

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JP2022071324A (en) 2022-05-16

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