JP2015015546A - High frequency module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency module that has a smaller size and a lower height.SOLUTION: A high frequency module 1 includes: a mounting substrate 2 with mounting electrodes 3 formed on one main surface 2a thereof; a plurality of first components 5a-5d, 4a, 4b having piezoelectric substrates 10a-10d with interdigital electrodes 11a-11d formed on one main surface thereof, and connection terminals 12a-12d electrically connected to the interdigital electrodes 11a-11d, respectively, and mounted on the mounting substrate 2 in such a manner that there is a gap between the one main surface of the piezoelectric substrates 10a-10d and the mounting substrate 2; a plurality of second components 6, 7 mounted on the mounting substrate 2 together with the first components 5a-5d, 4a, 4b; a sealing film 8a sealing in the first components 5a-5d, 4a, 4b so as to seal the gap between the piezoelectric substrates 10a-10d and the mounting substrate 2; and a sealing resin layer 9 covering the one main surface 2a of the mounting substrate 2, the sealing film 8a and the second components 6, 7.

Description

The present invention relates to a high-frequency module formed by sealing a component mounted on a mounting board.

  In a high-frequency module mounted on a portable terminal or the like, a surface acoustic wave filter (so-called SAW filter) may be used as a component mounted on a mounting board in order to extract a communication signal in a specific frequency band. This SAW filter generally has a comb electrode (IDT) formed as a functional element on one main surface of an element substrate formed of a piezoelectric body. By the way, a method for mounting this type of SAW filter includes face down bonding in which a SAW filter is disposed and mounted such that one main surface of the element substrate on which the functional element is formed faces the mounting substrate, and the functional element includes There is face-up bonding in which a SAW filter is arranged and mounted so that one main surface of the formed element substrate faces the side opposite to the mounting substrate. However, in recent years, a SAW filter is mounted due to a demand for downsizing of a high-frequency module. As the method, face-down bonding, which is advantageous for reducing the size and height of high-frequency modules, is widely used.

  In this type of high-frequency module, a sealing resin layer may be provided on one main surface of the mounting substrate on which the component is mounted for the purpose of protecting the mounted component. However, the above-described SAW filter loses its function when the functional element is covered with resin. For example, when the SAW filter is mounted by face-down bonding, one main substrate of the element substrate on which the functional element is formed is used. It is necessary to seal the SAW filter with the sealing resin layer in a state where the gap between the surface and the mounting substrate is hollow. Therefore, conventionally, as shown in FIG. 7, an electronic device including a SAW filter has been proposed (see Patent Document 1).

  The electronic device 100 includes a base substrate 101, a SAW filter 102 mounted on one main surface of the base substrate 101, and a resin film 103 that covers the one main surface of the base substrate 101 and the SAW filter 102, and includes a SAW filter. 102 is mounted on the base substrate 101 and packaged. This SAW filter 102 has a surface acoustic wave element of a comb-like electrode formed as a functional element on one main surface 102b of an element substrate 102a formed of a piezoelectric body. The one main surface 102b of the element substrate 102a The SAW filter 102 is disposed on the base substrate 101 so as to face the base substrate 101, and the SAW filter 102 is mounted on the base substrate 101 by face-down bonding. Further, a resin film 103 that covers the SAW filter 102 and the base substrate 101 is provided so as to be in close contact with the surface of the element substrate 102 a opposite to the base substrate 101 in the SAW filter 102. In this case, unlike the case where the sealing resin layer is formed by curing the liquid resin, the resin of the resin film 103 is formed between the main surface 102b on which the functional element of the element substrate 102a is formed and the base substrate 101. The gap can be sealed with the resin film 103 in a hollow state without flowing into the gap. Therefore, it is possible to protect the SAW filter 102 while ensuring the functionality of the SAW filter 102.

Japanese Patent Laid-Open No. 2002-184884 (see paragraphs 0021 to 0025, FIG. 1, etc.)

  Incidentally, some high-frequency modules include not only SAW filters but also other components such as a chip inductor, a chip capacitor, and an IC. In such a case, the above-described SAW filter 102 is conventionally packaged. The electronic device 100 is mounted on a mounting substrate together with other components, and the resin film 103 and other components are covered with a liquid resin to form a sealing resin layer, thereby obtaining a high frequency module. According to such a configuration, since the gap between the base substrate 101 and the SAW filter 102 is already sealed in the electronic device 100 with the resin film 103 in a hollow state, the liquid resin that forms the sealing resin layer can be obtained. The high frequency module can be formed without entering the gap and without impairing the function of the SAW filter 102. However, since the base substrate 101 is further required to mount the SAW filter 102 on the mounting substrate, the height of the high-frequency module is increased by the thickness of the base substrate 101.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a high-frequency module that can be reduced in size and height.

  In order to achieve the above object, a high-frequency module according to the present invention includes a mounting substrate having a connection electrode formed on one main surface thereof, an element substrate having a functional element formed on one main surface thereof, A connection terminal formed on one main surface and electrically connected to the functional element, wherein one main surface of the element substrate faces the one main surface of the mounting substrate, and one main surface of the mounting substrate The connection terminal is connected to the connection electrode of the mounting substrate and mounted in a predetermined region of the one main surface of the mounting substrate with a gap provided between the surface and the one main surface of the element substrate. A first component; a second component that is mounted together with the first component in a region other than the predetermined region of the one main surface of the mounting substrate; and the first component covering the first component and the one main surface of the mounting substrate. Provided in a predetermined region, one main surface of the element substrate and the A sealing film that seals the gap between the main surface of the packaging substrate in a sealed state, at least a part of the sealing film that covers the first main surface of the mounting substrate, the first component, and the first And a sealing resin layer provided so as to cover the two parts.

  In this case, a first component having an element substrate having a functional element formed on one main surface thereof and a connection terminal formed on one main surface of the element substrate and electrically connected to the functional element is a mounting substrate. The one main surface of the element substrate is opposed to the one main surface, and is mounted on the mounting substrate with a gap provided between the one main surface of the mounting substrate and the one main surface of the element substrate. Then, the first component is sealed with the sealing film in a state where the gap between the one main surface of the element substrate and the one main surface of the mounting substrate is sealed.

  For example, when the first component is a SAW filter, a comb-shaped electrode serving as a functional element is formed on one main surface of a piezoelectric substrate serving as an element substrate, and one main surface of the piezoelectric substrate is opposed to one main surface of the mounting substrate. In addition, the SAW filter is mounted on the mounting substrate in a state where a gap is provided between the one main surface of the mounting substrate and the one main surface of the piezoelectric substrate. In other words, the bare chip structure SAW filter is directly mounted on the mounting substrate by face-down bonding, and the SAW filter is sealed with the sealing film. At this time, the sealing film seals the SAW filter in a state where the gap between one main surface of the piezoelectric substrate on which the functional element (comb-shaped electrode) of the SAW filter is formed and one main surface of the mounting substrate is sealed. Therefore, the function of the SAW filter in the high frequency module is maintained. Also, the structure in which the bare chip structure SAW filter is directly mounted on the mounting substrate is different from the configuration in which the packaged electronic device is mounted on the mounting substrate by mounting the conventional SAW filter on the base substrate. Since the inner base substrate is not required, the height of the high-frequency module can be reduced by the thickness of the base substrate.

  In addition, in the conventional electronic device, it is necessary to make the size of the base substrate (area in plan view) larger than that of the SAW filter in order to mount the SAW filter. Although a mounting area corresponding to the size of the SAW filter may be secured on the mounting substrate when the bare chip structure SAW filter is directly mounted on the mounting substrate, the mounting substrate needs to be secured. It is possible to reduce the area of the main surface, and hence the high-frequency module.

  Further, since the second component mounted on the one main surface of the mounting substrate together with the first component is covered with the sealing resin layer, the connection reliability between the second component and the mounting substrate is improved.

  In addition, a plurality of the first components may be mounted on the predetermined region of the one main surface of the mounting substrate, and the plurality of first components may be covered with a single sealing film. In this case, the mounting interval between the first components can be narrowed compared to the case where the plurality of first components are sealed with individual sealing films. Moreover, the work man-hour which forms a sealing film can be reduced by sealing each 1st part collectively with a single sealing film.

  The first component includes a transmission filter and a reception filter, and the sealing film is provided to cover the transmission filter and a first sealing film provided to cover the transmission filter. You may provide the 2nd sealing film. Thus, when a 1st component is provided with a transmission filter and a reception filter, by sealing both filters with a 1st sealing film and a 2nd sealing film separately, it is with a transmission filter and a reception filter. Since the first and second sealing films are interposed therebetween, the isolation characteristics between the two filters are improved.

  The first component includes a first duplexer and a second duplexer in which a communication signal having a frequency band different from that of the communication signal used in the first duplexer is used, and the sealing film includes the first duplexer. A third sealing film provided by coating and a fourth sealing film provided by covering the second duplexer may be provided. As described above, when the first component includes the first duplexer and the second duplexer in which a communication signal having a frequency band different from that of the communication signal used in the first duplexer is used, both duplexers are connected to the third sealing film. Since the third and fourth sealing films are interposed between the first duplexer and the second duplexer by individually sealing with the fourth sealing film, the isolation characteristics between the duplexers are improves.

  Further, the sealing film may be formed of a thermosetting conductive resin, and the sealing film may be connected to a ground electrode formed on the mounting substrate. In this case, since the first component is covered with the sealing film made of the thermosetting conductive resin connected to the ground electrode formed on the mounting substrate, the shielding performance of the first component is improved.

  Moreover, the thermal conductivity of the sealing film may be higher than the thermal conductivity of the sealing resin layer. If it does in this way, the thermal conductivity of the heat | fever which generate | occur | produces from 1st components will improve compared with the case where the thermal conductivity of a sealing film is equivalent to the thermal conductivity of a sealing resin layer, or is low.

  Moreover, the said sealing resin layer may be formed with a thermosetting resin, and the elasticity modulus of the said sealing film may be lower than the elasticity modulus of the said sealing resin layer. When the first component is sealed with the sealing film, the thickness of the portion of the first component that contacts the edge portion of the element substrate in the first component of the sealing film is reduced, or the sealing film is the portion that contacts the edge portion of the element substrate. May be torn. Therefore, by making the elastic modulus of the sealing film lower than the elastic modulus of the sealing resin layer, stress applied to the portion of the sealing film that contacts the edge portion of the element substrate is easily dispersed throughout the sealing film. Further, it is possible to prevent the portion of the sealing film that contacts the edge portion of the element substrate from being thinned or torn. Further, since the thermosetting resin generally has higher hardness and mechanical strength than the thermoplastic resin, the protective function of the second component can be achieved by forming the sealing resin layer with the thermosetting resin. improves.

  In addition, the sealing film is formed so as to surround the first component, and has a glue margin that is in close contact with one main surface of the mounting substrate, and a width of the glue margin is equal to or greater than a thickness of the sealing film. Is preferred. In this way, the adhesive film has a width equal to or larger than the thickness of the sealing film, and the adhesion strength between the sealing film and the mounting substrate is increased by providing the adhesive margin in close contact with the one main surface of the mounting substrate. The hermeticity of sealing the gap between the one main surface of the element substrate of the first component and the one main surface of the mounting substrate in a hollow state is improved.

  The sealing resin layer may cover a portion other than the other main surface of the element substrate of the sealing substrate in a state where the sealing film on the other main surface of the element substrate is exposed. Good. In this case, the height of the high-frequency module can be reduced as compared with the case where the sealing resin layer also covers a portion of the sealing film on the other main surface of the element substrate.

  According to the present invention, there is provided a first component having an element substrate having a functional element formed on one main surface thereof and a connection terminal formed on the one main surface of the element substrate and electrically connected to the functional element. The one main surface of the element substrate faces the one main surface of the mounting substrate, and is mounted on the mounting substrate with a gap provided between the one main surface of the mounting substrate and the one main surface of the element substrate. . Then, the first component is sealed with the sealing film in a state where the gap between the one main surface of the element substrate and the one main surface of the mounting substrate is sealed.

  For example, when the first component is a SAW filter, a comb-shaped electrode serving as a functional element is formed on one main surface of a piezoelectric substrate serving as an element substrate, and one main surface of the piezoelectric substrate is opposed to one main surface of the mounting substrate. In addition, the SAW filter is mounted on the mounting substrate in a state where a gap is provided between the one main surface of the mounting substrate and the one main surface of the piezoelectric substrate. In other words, the bare chip structure SAW filter is directly mounted on the mounting substrate by face-down bonding, and the SAW filter is sealed with the sealing film. At this time, the SAW filter is sealed from the sealing film in a state where the gap between the one main surface of the piezoelectric substrate on which the functional element (comb-shaped electrode) of the SAW filter is formed and the one main surface of the mounting substrate is sealed. Therefore, the function of the SAW filter in the high frequency module is maintained. Also, by adopting a structure in which a bare chip structure SAW filter is directly mounted on a mounting substrate, unlike a conventional configuration in which an electronic device packaged with a SAW filter is mounted on a mounting substrate, a base substrate in the package is not required. Therefore, the height of the high-frequency module can be reduced by the thickness of the base substrate.

It is a top view of the high frequency module concerning a 1st embodiment of the present invention. It is sectional drawing of the high frequency module of FIG. It is a figure for demonstrating the manufacturing method of the high frequency module of FIG. It is a top view of the high frequency module concerning a 2nd embodiment of the present invention. It is sectional drawing of the high frequency module of FIG. It is sectional drawing of the high frequency module concerning 3rd Embodiment of this invention. It is sectional drawing of the electronic device mounted in the conventional high frequency module.

<First Embodiment>
A high-frequency module 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. 1 is a plan view of the high-frequency module 1 according to the first embodiment, FIG. 2 is a cross-sectional view of the high-frequency module 1, and shows a cross-sectional view taken along the line AA of FIG. Moreover, in FIG. 1, the sealing resin layer provided on the one main surface of the mounting substrate is not shown.

  As shown in FIGS. 1 and 2, the high-frequency module 1 according to this embodiment includes a mounting substrate 2 in which a mounting electrode 3 for component mounting (corresponding to the connection electrode of the present invention) is formed on one main surface 2a. The first and second duplexers 4a and 4b, the two transmission filters 5a and 5b, and the two reception filters 5c and 5d, which are mounted together in a predetermined region on the one main surface 2a of the mounting substrate 2, respectively, A plurality of (four in this embodiment) chip components 6 and ICs 7 mounted in a region other than the predetermined region of the first main surface 2a, the first and second duplexers 4a and 4b, and both transmission filters 5a and 5b. The sealing film 8a that covers both the receiving filters 5c and 5d and is provided in the predetermined region of the one main surface 2a of the mounting substrate 2, the one main surface 2a of the mounting substrate 2, the sealing film 8a, each chip And a sealing resin layer 9 provided to cover the part 6 and IC 7, for example, is mounted on a mother board the portable terminal apparatus.

  The mounting substrate 2 is a glass epoxy resin multilayer substrate, a low temperature co-fired ceramic (LTCC) multilayer substrate, a flexible multilayer wiring substrate, or the like. As described above, a plurality of component mounting electrodes 3 are mounted on one main surface 2a. It is formed. In addition, various wiring electrodes (not shown), via conductors (not shown), and the like are also formed therein. The mounting substrate 2 may have a single layer structure.

  Both transmission filters 5a and 5b and both reception filters 5c and 5d have the same configuration and are surface acoustic wave filters (so-called SAW filters) having a bare chip structure. For example, the transmission filter 5a will be specifically described as an example. The transmission filter 5a is formed on one main surface of the piezoelectric substrate 10a (corresponding to the element substrate of the present invention) such as LiTiO3, LiNbO3, and sapphire, and the piezoelectric substrate 10a. FIG. 2 shows a comb-shaped electrode 11a (corresponding to the functional element of the present invention) and a connection terminal 12a formed on one main surface of the piezoelectric substrate 10a and electrically connected to the comb-shaped electrode 11a. As described above, the one main surface of the piezoelectric substrate 10a faces the one main surface 2a of the mounting substrate 2, and a gap is provided between the one main surface 2a of the mounting substrate 2 and the one main surface of the piezoelectric substrate 10a. In this state, the connection terminal 12a is connected to the mounting electrode 3 of the mounting substrate 2 via the solder bump 13 and mounted on one main surface 2a of the mounting substrate 2, that is, mounted on the mounting substrate 2 by face-down bonding. It is. The other transmission filters 5b and both reception filters 5c and 5d also have piezoelectric substrates 10b to 10d, comb-shaped electrodes 11b to 11d, and connection terminals 12b to 12d, respectively, like the transmission filter 5a. It is mounted on one main surface 2a of the mounting substrate 2 by bonding.

  The first and second duplexers 4a and 4b are surface acoustic wave duplexers having a bare chip structure (so-called SAW duplexers). Like the transmission and reception filters 5a to 5d described above, a piezoelectric substrate and a piezoelectric substrate are used as element substrates, respectively. One main surface of the piezoelectric substrate having a comb-shaped electrode as a functional element formed on one main surface of the substrate and a connection terminal formed on one main surface of the piezoelectric substrate and electrically connected to the comb-shaped electrode And mounted on the one main surface 2a of the mounting substrate 2 with a gap provided between the main surface 2a and the one main surface 2a of the mounting substrate 2. At this time, a communication signal having a frequency band different from that of the communication signal used for the first duplexer is used for the second duplexer. Each of the transmission and reception filters 5a to 5d and the first and second duplexers 4a and 4b are fixedly mounted on a predetermined region of the one main surface 2a of the mounting board 2. Each of the transmission and reception filters 5a to 5d and the first and second duplexers 4a and 4b correspond to the first component of the present invention. Hereinafter, the transmission and reception filters 5a to 5d and the first and second duplexers 4a and 4b may be collectively referred to as the first components 5a to 5d, 4a, and 4b.

  Each chip component 6 is, for example, a chip capacitor or a chip inductor for impedance matching, and IC 7 is, for example, a switch IC, a power amplifier, an RF-IC, or the like, and each transmission on the one main surface 2a of the mounting substrate 2 is performed. The reception filters 5a to 5d and the first and second duplexers 4a and 4b are mounted using a known surface mounting technique in a region different from the predetermined region of the one main surface 2a of the mounting substrate 2. Each chip component 6 and IC 7 correspond to a second component of the present invention. Hereinafter, the chip parts 6 and the ICs 7 may be collectively referred to as the second parts 6 and 7.

  The sealing film 8a is formed of a thermosetting resin mainly composed of epoxy resin, silicon resin, polyimide, polyamide, or the like. Moreover, as shown in FIG. 1, the sealing film 8a is provided in the predetermined area | region of the one main surface 2a of the mounting substrate 2 in which each 1st components 5a-5d, 4a, 4b were mounted, and each 1st components 5a. .About.5d, 4a, 4b are coated at once. At this time, as shown in FIG. 2, the sealing film 8 a includes, on each of the first components 5 a to 5 d, 4 a and 4 b, one main surface of the piezoelectric substrates 10 a to 10 d on which the comb-shaped electrodes 11 a to 11 d are formed. The gap between the main surface 2a of the mounting substrate 2 is sealed, that is, the gap is sealed in a hollow state. The sealing film 8a may contain a filler such as SiO2 in order to adjust its linear expansion coefficient and elastic modulus. Moreover, in this embodiment, the thickness of the sealing film 8a is 10-500 micrometers.

  As shown in FIG. 2, the sealing film 8a is formed so as to surround each of the first components 5a to 5d, 4a, and 4b, and has a margin 8a1 that is in close contact with the one main surface 2a of the mounting substrate 2. The width W of the glue allowance 8a1 is formed to be equal to or greater than the thickness d of the sealing film 8a (W> d). When the adhesive force between the sealing film 8a and the mounting substrate 2 is small, peeling occurs at the interface between the sealing film 8a and the mounting substrate 2, and when the sealing resin layer 9 described later is formed, the sealing resin layer 9 The resin enters the gap generated by the interface peeling between the sealing film 8a and the mounting substrate 2, and one main surface of each of the first components 5a to 5d, 4a and 4b and one of the mounting substrates 2 is mounted. It may be difficult to maintain the gap between the main surface 2a in a hollow state. Therefore, by setting the width W of the adhesive margin 8a1 of the sealing film 8a to be equal to or greater than the thickness of the sealing film 8a, the contact area (sealing) where the adhesion between the sealing film 8a and the mounting substrate 2 becomes a desired value. Since the contact area between the film 8 and the mounting substrate 2 can be ensured, the above-described hollow sealing properties of the first components 5a to 5d, 4a, and 4b are improved.

  In addition, it is preferable that the thermal conductivity of the sealing film 8a is higher than the thermal conductivity of the sealing resin layer 9. As described above, each of the first components 5a to 5d, 4a and 4b is mounted by face-down bonding, and a gap between one main surface of the piezoelectric substrates 10a to 10d and one main surface 2a of the mounting substrate 2 is mounted. Is sealed by the sealing film 8a in a hollow state. In this case, air exists in the gap, but the air has lower thermal conductivity than the mounting substrate provided with the wiring electrode made of metal. Therefore, the first parts 5a to 5d, 4a, and 4b are sealed with the sealing film 8a while the gap between the one main surface of the piezoelectric substrates 10a to 10d and the one main surface 2a of the mounting substrate 2 is hollow. Then, the face-up in which the first components 5a to 5d, 4a and 4b are mounted in a state where the piezoelectric substrates 10a to 10d of the first components 5a to 5d, 4a and 4b are in contact with the one main surface 2a of the mounting substrate 2. Compared with the high-frequency module having a bonding configuration, heat generated from each of the first components 5a to 5d, 4a, and 4b is hardly released to the outside. Therefore, by making the thermal conductivity of the sealing film 8a higher than the thermal conductivity of the sealing resin layer 9, the heat dissipation characteristics of the first components 5a to 5d, 4a, and 4b are improved.

  Further, the elastic modulus of the sealing film 8 a is preferably lower than the elastic modulus of the sealing resin layer 9. As described above, since the sealing film 8a is formed with a thickness of 10 to 500 μm and is relatively thin, the first components 5a to 5d, 4a, and 4b are sealed with the sealing film 8a. As a result, the portions of the first parts 5a to 5d, 4a, and 4b of the sealing film 8a that are in contact with the edge portions of the piezoelectric substrates 10a to 10d may be thinned, or the sealing film 8a may be torn at that portion. . Therefore, by making the elastic modulus of the sealing film 8a lower than the elastic modulus of the sealing resin layer 9, the stress applied to the portion of the sealing film 8a that contacts the edge portions of the piezoelectric substrates 10a to 10d is reduced. Since it becomes easy to disperse | distribute to the whole, it can prevent that the part which contacts the edge part of piezoelectric substrate 10a-10d of the sealing film 8a becomes thin, or the sealing film 8a is torn at the part. Moreover, the same effect can be acquired also by making the linear expansion coefficient of the sealing film 8a larger than the linear expansion coefficient of the sealing resin layer 9.

  Further, a filler formed of a metal such as Ag or Cu is contained in the sealing film 8a, the sealing film 8a is formed of a thermosetting conductive resin, and the sealing film 8a is formed on the mounting substrate 2. It may be configured to be connected to the ground electrode. In this case, an electrode connected to the ground electrode may be formed on at least a part of the portion of the mounting substrate 2 that contacts the sealing film 8a, and the electrode and the sealing film 8a are electrically connected. . If it does in this way, the shielding characteristic of each 1st components 5a-5d, 4a, 4b will improve.

  The sealing resin layer 9 is formed of, for example, an epoxy resin, a phenol resin, a cyanate resin, a polyimide resin, a bismaleimide resin, and the like. The one main surface 2a of the mounting substrate 2, the sealing film 8a, and the second components 6 and 7 are used. Is provided. In addition, the sealing resin layer 9 in this embodiment is formed with a thermosetting epoxy resin.

(Manufacturing method of the high frequency module 1)
Next, the manufacturing method of the high frequency module 1 is demonstrated with reference to FIG. FIG. 3 is a diagram for explaining a method of manufacturing the high-frequency module 1 and corresponds to FIG. Moreover, (a)-(d) shows each process. Also, this manufacturing method can be applied to the high-frequency modules 1a and 1b according to the second and third embodiments described below.

  First, first and second duplexers 4a and 4b having a bare chip structure and transmission and reception filters 5a to 5d are prepared as first components. For example, the transmission filter 5a will be described as an example. The comb-shaped electrode 11a and each connection terminal 12a are formed on one main surface of the piezoelectric substrate 10a formed of LiTiO3, LiNbO3, sapphire, etc. with a thickness of about 4 μm. At this time, the comb-shaped electrode 11a and each connection terminal 12a are electrically connected. Next, solder bumps 13 are formed on each connection terminal 12a to form a transmission filter 5a having a bare chip structure. The other transmission and reception filters 5b to 5d and the first and second duplexers 4a and 4b can be formed by substantially the same process. Each chip component 6 and IC 7 are also prepared in advance as each second component.

  Next, as shown in FIG. 3A, the first components 5 a to 5 d, 4 a, 4 b and the second components 6, 7 are mounted on the one main surface 2 a of the mounting substrate 2. For example, the mounting method of the first components 5a to 5d, 4a, 4b will be described as an example. A solder paste is applied in advance on each mounting electrode 3 of the mounting substrate 2 by a printing method, a dispensing method, a transfer method, etc. After mounting the first components 5a to 5d, 4a and 4b with the solder bumps 13 thereon, the mounting substrate 2 and the first components 5a to 5d, 4a and 4b are connected by reflow. As another example of the method of mounting the first components 5a to 5d, 4a, 4b on the mounting substrate 2, a flux is applied to the mounting substrate 2 in advance by a printing method, a dispensing method, a transfer method, or the like. A method of mounting the first parts 5a to 5d, 4a and 4b with the solder bumps 13 thereon, and transferring the flux to the solder bumps 13 of the first parts 5a to 5d, 4a and 4b, A method of mounting the one component 5a-5d, 4a, 4b on the mounting substrate 2, and transferring the solder paste containing flux to the solder bump 13 of each first component 5a-5d, 4a, 4b, There is a method of mounting 5a to 5d, 4a, 4b on the mounting substrate 2. In each of the first components 5a to 5d, 4a, and 4b, a gap is formed between one main surface of the piezoelectric substrates 10a to 10d and one main surface 2a of the mounting substrate 2 in a state of being mounted on the mounting substrate 2. In order to form, the solder bumps 13 of the first components 5a to 5d, 4a and 4b are formed to have a height of 70 to 100 μm.

  Next, the mounting substrate 2 on which the first components 5a to 5d, 4a, 4b and the second components 6, 7 are mounted is cleaned. As a cleaning method, the mounting substrate 2 is dipped in a glycol-based / alcohol-based cleaning solution for about 10 minutes, and then the mounting substrate 2 is dried by washing with pure water. The mounting substrate 2 is acetone, isopropyl alcohol (IPA). For example, there are a method in which the mounting substrate 2 is dried by further cleaning with pure water after being immersed in a solvent such as 10 minutes, and a method in which cleaning is performed using oxygen plasma. The first parts 5a to 5d, 4a and 4b cannot be sufficiently cleaned if there are flux residues and cleaning liquid residues at the comb-shaped electrodes 11a to 11d. There is a need to.

  Next, as shown in FIG. 3B, a semi-cured flat plate-like seal is formed on a predetermined region of the one main surface 2a of the mounting substrate 2 on which the first components 5a to 5d, 4a, and 4b are mounted. By placing the film 8a and heating and pressing in a vacuum state using a predetermined pressing member 14 from above the sealing film 8a, each of the first films is sealed by the sealing film 8a as shown in FIG. Only the parts 5a to 5d, 4a and 4b are sealed together. Thus, when each 1st components 5a-5d, 4a, 4b are sealed with the sealing film 8a, each above-mentioned clearance gap between each 1st components 5a-5d, 4a, 4b will be sealed in a hollow state. At this time, a margin 8a1 is formed on the sealing film 8a so as to be in close contact with the one main surface 2a of the mounting substrate 2. In addition, the sealing film 8a in this embodiment contains a filler such as SiO 2 with an epoxy resin, polyimide, polyimide amide or the like as a main component.

  Moreover, regarding the mounting of the first components 5a to 5d, 4a, and 4b on the mounting substrate 2, for example, each of the first components 5a to 5d, 4a, and 4b is placed at a predetermined position on the flat sealing film 8a. A sealing film with a first component to which the other main surface of the piezoelectric substrates 10 a to 10 d is attached may be prepared, and the sealing film with the first component may be mounted on the mounting substrate 2.

  Next, as shown in FIG. 3 (d), a liquid epoxy resin containing a filler such as SiO2 covers the one main surface 2a of the mounting substrate 2, the sealing film 8a, and the second components 6 and 7. After the application and vacuum defoaming to remove bubbles inside the epoxy resin, the epoxy resin is cured to form the sealing resin layer 9, and the high frequency module 1 is manufactured. At this time, the sealing resin layer 9 can be formed by a coating method, a printing method, a compression mold method, a transfer mold method, or the like. Note that the sealing resin layer 9 may be formed using a solid resin or a sheet-like resin instead of the liquid resin.

  Therefore, according to the above-described embodiment, in each of the first components 5a to 5d, 4a and 4b, the comb-shaped electrodes 11a to 11d are formed on one main surface of the piezoelectric substrates 10a to 10d, and the one main component of the mounting substrate 2 is formed. Each main surface of the piezoelectric substrates 10a to 10d faces the surface 2a, and a gap is provided between the one main surface 2a of the mounting substrate 2 and the one main surface of the piezoelectric substrates 10a to 10d. One component 5a to 5d, 4a, 4b is mounted on one main surface 2a of the mounting substrate 2. In other words, each first component 5a to 5d, 4a, 4b having a bare chip structure is directly mounted on the mounting substrate 2 by face-down bonding. And since the sealing film 8a seals the above-described gaps of the respective first components, the function as the filter or duplexer of each of the first components 5a to 5d, 4a, 4b is maintained. The Further, the conventional SAW filter 102 shown in FIG. 7 is mounted on the base substrate 101 by adopting a structure in which the first components 5a to 5d, 4a, and 4b having the bare chip structure are directly mounted on the mounting substrate 2. Unlike the configuration in which the packaged electronic device 100 is mounted on the mounting substrate 2, the base substrate 101 in the package is not required, so that the height of the high-frequency module 1 can be reduced by the thickness of the base substrate 101. .

  Further, in the conventional electronic device 100 shown in FIG. 7, the size (area in plan view) of the base substrate 101 needs to be larger than that of the SAW filter 102 in order to mount the SAW filter 102. 2, when the electronic device 100 is mounted, a mounting area corresponding to the size of the base substrate 101 must be secured on the mounting substrate 2. Therefore, when the first components 5a to 5d, 4a and 4b having the bare chip structure are directly mounted on the mounting substrate 2 as in the high-frequency module 1 of this embodiment, the first components 5a to 5d, Since a mounting area corresponding to the sizes of 4a and 4b may be ensured on the one main surface 2a of the mounting substrate 2, the area of the main surface of the mounting substrate 2 can be reduced, and consequently the high-frequency module 1 can be reduced. it can.

  In addition, the sealing resin layer 9 of this embodiment is formed of a thermosetting epoxy resin, but the thermosetting resin generally has higher hardness and mechanical strength than the thermoplastic resin. Therefore, by forming the sealing resin layer 9 with the thermosetting resin in this way, the protection function for the second components 6 and 7 is improved. Further, when each of the second components 6 and 7 is covered with a liquid resin that forms the sealing resin layer 9, each of the second components 6 and 7 is sealed in the gap between the main surface 2 a of each mounting substrate 2. Since the resin of the layer 9 is filled with the sealing resin layer 9, the connection reliability between the second components 6 and 7 and the mounting substrate 2 is improved.

  Moreover, since each 1st components 5a-5d, 4a, 4b are collectively mounted in the predetermined area | region of the one main surface 2a of the mounting substrate 2, and are sealed collectively with the same sealing film 8a, each 1st Compared with the case where the components 5a to 5d, 4a, and 4b are sealed with individual films, the mounting interval between the first components 5a to 5d, 4a, and 4b can be narrowed. Moreover, the work man-hour which forms the sealing film 8a can be reduced by collectively sealing each 1st components 5a-5d, 4a, 4b with the same sealing film 8a.

Second Embodiment
A high frequency module 1a according to a second embodiment of the present invention will be described with reference to FIGS. 4 is a plan view of the high-frequency module 1a, and FIG. 5 is a cross-sectional view taken along line BB in FIG. In FIG. 4, the sealing resin layer 9 is not shown.

  The high-frequency module 1a according to this embodiment differs from the high-frequency module 1 of the first embodiment described with reference to FIGS. 1 and 2 in that the first components 5a to 5d, 4a, and 4b are individually sealed. It is a point that has been. Since other configurations are the same as those of the high-frequency module 1 of the first embodiment, description thereof is omitted by attaching the same reference numerals.

  In this case, as shown in FIGS. 4 and 5, the two transmission filters 5a and 5b are collectively sealed by the first sealing film 8b, and the two reception filters 5c and 5d are the second sealing film 8c. Are collectively sealed. The first and second duplexers 4a and 4b are individually sealed with the third and fourth sealing films 8d and 8e, respectively. The two transmission filters 5a and 5b and the two reception filters 5c and 5d may be individually sealed with another sealing film.

  With this configuration, for example, the first sealing film 8b and the second sealing film 8c are interposed between the transmission filters 5a and 5b and the reception filters 5c and 5d, so that the transmission filters 5a and 5b Isolation characteristics between the reception filters 5c and 5d are improved. Similarly, the isolation characteristics between the first and second duplexers 4a and 4b using communication signals of different frequency bands are improved.

<Third Embodiment>
A high frequency module 1b according to a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view of the high-frequency module 1b and corresponds to FIG.

  The high-frequency module 1b according to this embodiment is different from the high-frequency module 1 according to the first embodiment described with reference to FIGS. 1 and 2 as shown in FIG. In a state where the sealing film 8a on the other main surface of the piezoelectric substrates 10a to 10d of the one component 5a to 5d, 4a and 4b is exposed, a portion other than the exposed portion of the sealing film 8a is covered. is there. Since other configurations are the same as those of the high-frequency module 1 of the first embodiment, description thereof is omitted by attaching the same reference numerals.

  In this case, the sealing resin layer 9 is a piezoelectric substrate that is opposite to the main surface on which the comb electrodes 11a to 11d of the piezoelectric substrates 10a to 10d are formed in each of the first components 5a to 5d, 4a, and 4b. With the sealing film 8a on the other main surface of 10a to 10d exposed, the other part of the sealing film 8a is covered and provided. If it does in this way, compared with the structure which the sealing resin layer 9 coat | covers the whole sealing film 8a like the high frequency module 1 of 1st Embodiment, the height reduction of the high frequency module 1b can be achieved. .

  Moreover, when the colors of the sealing film 8a and the sealing resin layer 9 are different, the portion exposed from the sealing resin layer 9 of the sealing film 8a can be used as a direction recognition mark of the high-frequency module 1b.

  Note that the present invention is not limited to the above-described embodiments, and various modifications other than those described above can be made without departing from the spirit of the invention. In the method of manufacturing the high-frequency modules 1, 1a, 1b, the case where the solder bumps 13 are formed on the connection terminals 12a-12d of the first components 5a-5d, 4a, 4b has been described. The stud bumps made of Au may be provided on the connection terminals 12a to 12d of the first components 5a to 5d, 4a and 4b, or the post electrodes may be provided by Au plating or the like. In this case, the height of each Au stud bump and Au post electrode is formed to about 70 μm, and pressure, heating, and ultrasonic vibration are applied when the first components 5a to 5d, 4a, and 4b are mounted on the mounting substrate 2. By doing so, the first components 5a to 5d, 4a, and 4b may be connected to the mounting board 2. When connected in this way, the height of the Au stud bump or Au post electrode after connecting the first components 5a to 5d, 4a, 4b to the mounting substrate 2 is about 15 μm. Since the comb-shaped electrodes 11a to 11d of the first components 5a to 5d, 4a and 4b are formed with a thickness of about 4 μm, even after the first components 5a to 5d, 4a and 4b are connected to the mounting substrate 2. The comb-shaped electrodes 11a to 11d of the first components 5a to 5d, 4a and 4b do not come into contact with the one main surface 2a of the mounting substrate 2. Therefore, a gap is provided between one main surface of the piezoelectric substrates 10a to 10d of each of the first components 5a to 5d, 4a, and 4b and one main surface of the mounting substrate 2, and each of the first components 5a to 5d. The function as a filter or duplexer of 5d, 4a, 4b is not impaired.

  Further, in each of the above-described embodiments, when mounted by face-down bonding, the one main surface of the element substrate (piezoelectric substrates 10a to 10d) and the one main surface 2a of the mounting substrate 2 are used in order to exhibit the function. The first parts that need to be sealed in a hollow state are surface acoustic wave filters (respective transmission and reception filters 5a to 5d) and surface acoustic wave duplexers (first and second duplexers 4a and 4b). Although a certain case has been described, a BAW filter or MEMS (Micro Electro Mechanical Systems) may be used as the other first component.

  Moreover, in the manufacturing method of the high frequency module 1, 1a, 1b according to each of the above-described embodiments, the case where the solder bumps 13 are provided on the connection terminals 12a-12d of the first components 5a-5d, 4a, 4b has been described. Solder bumps may be provided on the mounting electrodes 3 of the mounting substrate 2.

  Further, the present invention can be applied to various high-frequency modules formed by sealing the components having the above-described configuration mounted on a mounting board.

1, 1a, 1b High-frequency module 2 Mounting substrate 3 Mounting electrode (connection electrode)
4a First duplexer (first part)
4b Second diplexer (first part)
5a, 5b Transmission filter (first part)
5c, 5d Receive filter (first part)
6 Chip parts (second part)
7 IC (second part)
8a sealing film 8b first sealing film 8c second sealing film 8d third sealing film 8e fourth sealing film 9 sealing resin layer 10a to 10d piezoelectric substrate (element substrate)
11a to 11d Comb electrodes (functional elements)
12a-12d connection terminal 8a1 paste allowance

Claims (9)

A mounting substrate having a connection electrode formed on one main surface thereof;
It has an element substrate having a functional element formed on one main surface thereof, and a connection terminal formed on one main surface of the element substrate and electrically connected to the functional element, on one main surface of the mounting substrate. The connection terminal is connected to the mounting substrate in a state where the one main surface of the element substrate faces and a gap is provided between the one main surface of the mounting substrate and the one main surface of the element substrate. A first component connected to an electrode and mounted on a predetermined region of one main surface of the mounting substrate;
A second component that is mounted together with the first component in a region other than the predetermined region on one main surface of the mounting substrate;
Covering the first component, provided in the predetermined region of the one main surface of the mounting substrate, and sealing the gap between the one main surface of the element substrate and the one main surface of the mounting substrate in a sealed state Sealing film to be
A high-frequency module, comprising: one main surface of the mounting substrate; at least a part of the sealing film covering the first component; and a sealing resin layer provided covering the second component. A plurality of the first components are mounted on the predetermined region of the one main surface of the mounting substrate,
The high-frequency module according to claim 1, wherein the plurality of first parts are covered with a single sealing film. The first component includes a transmission filter and a reception filter,
The sealing film is
A first sealing film provided to cover the transmission filter;
The high-frequency module according to claim 1, further comprising a second sealing film provided so as to cover the reception filter. The first component includes a first duplexer and a second duplexer in which a communication signal having a frequency band different from that of the communication signal used in the first duplexer is used.
The sealing film is
A third sealing film provided to cover the first duplexer;
The high-frequency module according to claim 1, further comprising a fourth sealing film provided so as to cover the second duplexer. The sealing film is formed of a thermosetting conductive resin,
The high-frequency module according to claim 1, wherein the sealing film is connected to a ground electrode formed on the mounting substrate.   The high frequency module according to claim 1, wherein a thermal conductivity of the sealing film is higher than a thermal conductivity of the sealing resin layer. The sealing resin layer is formed of a thermosetting resin;
The high-frequency module according to claim 1, wherein an elastic modulus of the sealing film is lower than an elastic modulus of the sealing resin layer.   The sealing film is formed so as to surround the first component, and has a glue margin that is in close contact with one main surface of the mounting substrate, and the width of the glue margin is equal to or greater than the thickness of the sealing film. The high frequency module according to claim 1, wherein the high frequency module is characterized in that:   The sealing resin layer covers a portion of the sealing film other than on the other main surface of the element substrate in a state where the sealing film on the other main surface of the element substrate is exposed. A high-frequency module according to any one of claims 1 to 8.

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