JP2022051614A - module - Google Patents

Abstract

To provide a low-loss module that is impedance-matched by an optimum inductance value at a low cost.SOLUTION: A module has: a wiring board; and an inductor mounted on the wiring board and that has a plurality of bump pads at least at one of an input terminal side and an output terminal side, an arbitrary one of the plurality of bump pads serving as an input terminal or an output terminal.SELECTED DRAWING: Figure 2

Description

The present invention relates to modules, including front-end modules.

Smartphones represented by mobile communication terminals are required to support communication in a plurality of high frequency bands. For this reason, a front-end module equipped with a plurality of bandpass filters that pass communication in a high frequency band is used.

Further, in the front-end module, an inductor for impedance matching the bandpass filter and the low noise amplifier is used between the bandpass filter and the low noise amplifier (Low Noise Amplifier).

Further, in recent years, there has been a strong demand for miniaturization of front-end modules due to the demand for thinner and more integrated smartphones, and the inductor for impedance matching is becoming IPD (Integrated Passive Device).

Patent Document 1 discloses an example of a technique relating to impedance matching of a front-end module.

JP-A-2019-199292

The main problem to be solved by the present invention will be described.

In recent years, inductors for impedance matching have become almost indispensable for integrated circuits such as bandpass filters and low noise amplifiers mounted on front-end modules.

However, the optimum value of the inductance value required for impedance matching differs depending on the combination of the bandpass filter and the low noise amplifier, and it is necessary to prepare an inductor having a number of inductance values according to the number of combinations having different optimum values.

Increasing the cost of production, testing, and management for each number of inductors required is also a major issue in production control of actual front-end modules.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a module and a front-end module which are impedance-matched by an optimum inductance value at low cost.

In order to achieve the above problems, in the present invention,
Wiring board and
It is mounted on the wiring board and has a plurality of bump pads on at least one of an input terminal or an output terminal, and any one of the plurality of bump pads has an inductor as an input terminal or an output terminal. It was made into a module, which is characterized by this.

Wiring board and
A first inductor mounted on the wiring board, having a plurality of bump pads on at least one of an input terminal or an output terminal, and any one of the plurality of bump pads is an input terminal or an output terminal. When,
A second inductor mounted on the wiring board, having a plurality of bump pads on at least one of an input terminal or an output terminal, and any one of the plurality of bump pads is an input terminal or an output terminal. When,
The first bandpass filter connected to the first inductor and
One embodiment of the present invention is a module having a second bandpass filter connected to the second inductor.

It is one embodiment of the present invention that the wiring board includes a plurality of bump pads corresponding to the plurality of bump pads.

It is one embodiment of the present invention that the inductor is an IPD (Integrated Passive Device).

It is one embodiment of the present invention to include a first low noise amplifier connected to the first inductor and a second low noise amplifier connected to the second inductor.

One embodiment of the present invention is that the input terminal or output terminal of the first inductor is formed of a bump pad different from the input terminal or output terminal of the second inductor.

It is one embodiment of the present invention that the input terminal or the output terminal of the first inductor is formed by the same bump pad as the input terminal or the output terminal of the second inductor.

It is one embodiment of the present invention that at least one of the first bandpass filter or the second bandpass filter is a surface acoustic wave filter.

It is one embodiment of the present invention that at least one of the first bandpass filter or the second bandpass filter is a filter using an elastic thin film resonator.

According to the present invention, it is possible to provide a front-end module that is impedance-matched with an optimum inductance value at low cost.

FIG. 1 is a cross-sectional view of the module 1 according to the present embodiment. FIG. 2 is a diagram showing an outline of the structure of the inductor 3. FIG. 3 is a diagram showing a configuration example of a SAW filter that can be used for the bandpass filter 5. FIG. 4 is a plan view showing an example in which the surface acoustic wave element 52 is an elastic surface wave resonator. FIG. 5 is a cross-sectional view showing an example of a piezoelectric thin film resonator in which the elastic wave element 52 is a piezoelectric thin film resonator. FIG. 6 is a diagram showing an outline of the circuit configuration of the front-end module 100 according to the second embodiment. FIG. 7 is a cross-sectional view of the front end module 100 according to the second embodiment.

Hereinafter, the present invention will be clarified by explaining specific embodiments of the present invention with reference to the drawings.

(Example 1)
FIG. 1 is a cross-sectional view of the module 1 according to the present embodiment.

As shown in FIG. 1, the module 1 according to this embodiment includes a wiring board 2, an inductor 3 and a bandpass filter 5 mounted on the wiring board 2.

The inductor 3 and the bandpass filter 5 are mounted on the wiring board 2 by flip-chip bonding via the bumps 7.

As the bump 7, for example, a gold bump can be used. The height of the bump 7 is, for example, 20 μm to 50 μm.

A sealing portion 9 is formed so as to cover the inductor 3 and the bandpass filter 5. The sealing portion 9 may be formed of, for example, an insulator such as a synthetic resin, or a metal may be used. As the synthetic resin, for example, epoxy resin, polyimide and the like can be used, but the synthetic resin is not limited thereto. Preferably, an epoxy resin is used and a low temperature curing process is used to form the sealing portion 9.

As the wiring board 2, for example, a multilayer substrate made of resin, a low temperature co-fired ceramics (LTCC) multilayer substrate made of a plurality of dielectric layers, or the like is used.

A metal pattern is formed on the mounting surface of the wiring board 2 so as to correspond to the plurality of bump pads 32 of the inductor 3. As will be described later, this is to enable electrical connection regardless of which of the bump pads 32 of the plurality of bump pads 32 of the inductor 3 the bumps are formed and the flip chip bonding is performed.

FIG. 2 is a diagram showing an outline of the structure of the inductor 3.

The inductor 3 can be, for example, an inductor having an inductance value of about 0.5 nH to 2 nH when the frequency is 5 GHz. The inductor can be an IPD for the miniaturization and integration of the module.

As shown in FIG. 2, the inductor 3 has a winding 33 formed on a substrate 31 made of an insulator or a semiconductor so as to be electrically connected to a plurality of bump pads 32.

As the substrate 31, high resistance silicon, gallium arsenide, sapphire, polycrystalline alumina, glass and the like can be used. However, the material of the substrate 31 is not limited to these materials. The thickness of the substrate 31 can be, for example, 200 μm.

Instead of directly forming the plurality of bump pads 32 and windings 33 on the substrate 31, a layer of another material may be provided between the substrate 31 and the plurality of bump pads 32 and windings 33. For example, in order to secure insulation, silicon dioxide or the like may be provided between the substrate 31 and the plurality of bump pads 32 and the winding 33 as an insulating layer.

The plurality of bump pads 32 and windings 33 may use a metal or alloy containing gold, copper, aluminum or the like as a main component, or other metals or alloys may be used.

The thickness of the plurality of bump pads 32 and the winding 33 can be, for example, 3 μm to 5 μm. Further, the width of the pattern of the winding 33 can be, for example, 35 μm to 70 μm. Further, the interval between the patterns of the windings 33 can be, for example, 20 μm to 40 μm.

The width and spacing of the winding 33 pattern can be increased or decreased from the middle of the winding 33 pattern. For example, when the frequency is 5 GHz, a desired inductance value in each of the plurality of bump pads can be realized.

The winding 33 is electrically connected to the output terminal 37 from the central portion via the insulating layer 39. Wiring may be formed with a hollow structure without using an insulating layer.

This embodiment shows an example in which the bump pad having the longest winding 33 among the plurality of bump pads 32 is adopted as the input terminal 35 and mounted.

However, the example shown in FIG. 2 is only one example. Depending on whether the inductor is connected to the receive filter or the transmit filter of the bandpass filter, the low noise amplifier, the power amplifier, etc., the inductor is actually connected by a bump among a plurality of bump pads. The terminal can be both an output terminal and an input terminal.

In some cases, the optimum inductance value can be achieved by using another bump pad. The bump pad having the optimum inductance value can be appropriately selected depending on which component in the circuit of the front-end module the module of the first embodiment is mounted.

Next, a configuration example of the bandpass filter 5 will be described.

FIG. 3 is a diagram showing a configuration example of a SAW filter that can be used for the bandpass filter 5.

As shown in FIG. 3, the elastic wave element 52 and the wiring pattern 54 are formed on the piezoelectric substrate 50.

For the piezoelectric substrate 50, for example, a piezoelectric single crystal such as lithium tantalate, lithium niobate, or quartz, or piezoelectric ceramics can be used. Further, the piezoelectric substrate 50 may be joined to the support substrate. As the support substrate, for example, a sapphire substrate, an alumina substrate, a spinel substrate, or a silicon substrate can be used.

The wiring pattern 54 includes wiring constituting the input pad In, the output pad Out, and the ground pad GND. Further, the wiring pattern 54 is electrically connected to the elastic wave element 52.

An insulator 56 is formed on the wiring pattern 54. As the insulator 56, for example, polyimide can be used. The insulator 56 is formed, for example, with a film thickness of 1000 nm.

A second wiring pattern 58 is formed on the insulator 56. The second wiring pattern 58 is formed so as to three-dimensionally intersect the wiring pattern 54 via the insulator 56.

The elastic wave element 52, the wiring pattern 54, and the second wiring pattern 58 are made of an appropriate metal or alloy such as silver, aluminum, copper, titanium, and palladium. Further, these metal patterns may be formed by a laminated metal film formed by laminating a plurality of metal layers. The thickness of the elastic wave element 52, the wiring pattern 54, and the second wiring pattern 58 can be, for example, 150 nm to 400 nm.

FIG. 4 is a plan view showing an example in which the surface acoustic wave element 52 is an elastic surface wave resonator.

As shown in FIG. 4, an IDT (Interdigital Transducer) 52a and a reflector 52b that excite surface acoustic waves are formed on the piezoelectric substrate 50. The IDT 52a has a pair of comb-shaped electrodes 52c facing each other. The comb-shaped electrode 52c has a bus bar 52e that connects a plurality of electrode fingers 52d and a plurality of electrode fingers 52d. Reflectors 52b are provided on both sides of the IDT 52a.

The IDT 52a and the reflector 52b are made of, for example, an alloy of aluminum and copper. The IDT 52a and the reflector 52b are thin films having a thickness of, for example, 150 nm to 400 nm. The IDT 52a and the reflector 52b may contain other metals, such as any suitable metal such as titanium, palladium, silver or alloys thereof, or may be formed of these alloys. Further, the IDT 52a and the reflector 52b may be formed of a laminated metal film formed by laminating a plurality of metal layers.

The elastic wave element 52 can be appropriately adopted in DMS design or ladder design so as to obtain desired characteristics as a bandpass filter.

FIG. 5 is a cross-sectional view showing an example of a piezoelectric thin film resonator in which the elastic wave element 52 is a piezoelectric thin film resonator.

As shown in FIG. 5, the 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 elastic waves in the thickness longitudinal vibration mode in the piezoelectric film 62.

As the chip substrate 60, for example, a semiconductor substrate such as silicon or an insulating substrate such as sapphire, alumina, spinel or glass can be used. For the piezoelectric film 62, for example, aluminum nitride can be used. For the lower electrode 64 and the upper electrode 66, for example, a metal such as ruthenium can be used.

According to one embodiment of the present invention described above, it is possible to provide a low-loss module with impedance matching. That is, according to the module of the present invention, a low-mix, mass-produced inductor can be used, and a low-cost, low-loss module is provided.

(Example 2)
FIG. 6 is a diagram showing an outline of the circuit configuration of the front-end module 100 according to the second embodiment.

As shown in FIG. 6, the common input terminal 101 of the front end module 100 is connected to the antenna terminal ANT. Although not shown, the first output terminal 103 and the second output terminal 105 are connected to a signal processing circuit.

From the common input terminal, the signal passing through the first bandpass filter BPF1 and the signal passing through the second bandpass filter BPF2 are separated by the switching circuit SW.

The signal that has passed through the first bandpass filter BPF1 is impedance-matched by the first inductor 107, amplified by the first low noise amplifier LNA1, and output from the first output terminal 103.

The signal that has passed through the second bandpass filter BPF2 is impedance-matched by the second inductor 109, amplified by the second low noise amplifier LNA2, and output from the second output terminal 105.

FIG. 7 is a cross-sectional view of the front end module 100 according to the second embodiment.

As shown in FIG. 7, in the front-end module 100, a first bandpass filter BPF1, a second bandpass filter BPF2, a first inductor 107, and a second inductor 109 are mounted on the main surface of the substrate 110. Has been done.

The integrated circuit component IC is mounted on the other main surface of the board 110. The integrated circuit component IC includes a switching circuit SW, a first low noise amplifier LNA1 and a second low noise amplifier LNA2.

Further, a common input terminal 101, a first output terminal 103, and a second output terminal 105 (not shown in FIG. 7) are formed on the other main surface of the board 110, and are mounted on the motherboard of the mobile communication terminal. It has a structure of

Here, since the first bandpass filter BPF1 and the second bandpass filter BPF2 have different frequency bands to pass through, the inductance required for impedance matching between the first bandpass filter BPF1 and the first low noise amplifier LNA1. The value and the inductance value required for impedance matching between the second bandpass filter BPF2 and the second low noise amplifier LNA2 may differ.

Since the first inductor 107 and the second inductor 109 have the same configurations as those described with reference to FIG. 2 in the first embodiment, the description thereof will be omitted. Further, the first inductor 107 and the second inductor 109 are the same products before mounting, except for manufacturing errors.

At the time of mounting, the bump pad having the smallest inductance value was selected for the first inductor 107 and used as the input terminal of the first inductor 107. The specific inductance value was 1.0 nH.

At the time of mounting, the bump pad having the largest inductance value was selected for the second inductor 109 and used as the input terminal of the second inductor 109. The specific inductance value was 1.5 nH.

In this embodiment, the bump pads used as the input terminals of the first inductor 107 and the second inductor 109 are bump pads formed at different positions, but depending on the design conditions of the module and the like, the first The input or output terminals of the inductor and the second inductor may be the same bump pad.

A metal pattern is formed on the main surface of the substrate 110 so as to correspond to a plurality of bump pads of the first inductor 107 and the second inductor 109, respectively. This is to enable electrical connection even if a bump is formed on any of the plurality of bump pads of the first inductor 107 and the second inductor 109 and flip-chip bonding is performed. be.

Other configurations are omitted because they overlap with the contents described in the first embodiment.

According to the second embodiment of the present invention described above, it is possible to provide a low-loss front-end module that is impedance-matched by an optimum inductance value at low cost.

As a matter of course, the present invention is not limited to the embodiments described above, but includes all embodiments that can achieve the object of the present invention.

Also, although some aspects of at least one embodiment have been described above, it should be appreciated that various modifications, modifications and improvements are readily recalled to those of skill in the art. Such modifications, modifications and improvements are intended to be part of this disclosure and are intended to be within the scope of the invention. It should be understood that the methods and embodiments of the apparatus described herein are not limited to application to the details of the structure and arrangement of the components described above or illustrated in the accompanying drawings. Methods and devices can be implemented in other embodiments and implemented or implemented in various embodiments. Specific implementation examples are given herein for illustrative purposes only and are not intended to be limited. Also, the expressions and terms used herein are for explanatory purposes only and should not be considered limiting. The use of "include", "provide", "have", "include" and variations thereof herein means inclusion of the items listed below and their equivalents and additional items. References to "or (or)" shall be construed so that any term described using "or (or)" refers to one, more than, and all of the terms in the description. Can be done. References to front-back, left-right, top-bottom top-bottom, and horizontal-vertical are intended for convenience of description, and the components of the present invention are not limited to any one of the positional or spatial orientations. Therefore, the above description and drawings are merely examples.

1 module 2 wiring board 3 inductor 31 board 32 bump pad 33 winding 35 input terminal 37 output terminal 39 insulation layer 5 bandpass filter 50 piezoelectric board 52 elastic wave element 54 wiring pattern 56 insulator 58 second wiring pattern 60 chip board 62 Piezoelectric film 64 Lower electrode 66 Upper electrode 68 Void 7 Bump 9 Sealing part 100 Front end module 101 Common input terminal 103 1st output terminal 105 2nd output terminal 107 1st inductor 109 2nd inductor 110 Board ANT antenna terminal SW Switching circuit BPF1 1st bandpass filter BPF2 2nd bandpass filter LNA1 1st low noise amplifier LNA2 2nd low noise amplifier IC integrated circuit component

Claims (9)

Wiring board and
It is mounted on the wiring board and has a plurality of bump pads on at least one of an input terminal or an output terminal, and any one of the plurality of bump pads has an inductor as an input terminal or an output terminal. module. Wiring board and
A first inductor mounted on the wiring board, having a plurality of bump pads on at least one of an input terminal or an output terminal, and any one of the plurality of bump pads is an input terminal or an output terminal. When,
A second inductor mounted on the wiring board, having a plurality of bump pads on at least one of an input terminal or an output terminal, and any one of the plurality of bump pads is an input terminal or an output terminal. When,
The first bandpass filter connected to the first inductor and
A module having a second bandpass filter connected to the second inductor. The module according to claim 1 or 2, wherein the wiring board includes a plurality of bump pads corresponding to the plurality of bump pads. The module according to claim 1 or 2, wherein the inductor is an IPD (Integrated Passive Device). The module according to claim 2, further comprising a first low noise amplifier connected to the first inductor and a second low noise amplifier connected to the second inductor. The module according to claim 2, wherein the input terminal or output terminal of the first inductor is formed of a bump pad different from the input terminal or output terminal of the second inductor. The module according to claim 2, wherein the input terminal or output terminal of the first inductor is formed of the same bump pad as the input terminal or output terminal of the second inductor. The module according to claim 2, wherein at least one of the first bandpass filter or the second bandpass filter is a surface acoustic wave filter. The module according to claim 2, wherein at least one of the first bandpass filter or the second bandpass filter is a filter using an elastic thin film resonator.

Images