High-frequency module and communication device

Abstract

The present invention improves reliability in a high-frequency module. A high-frequency module (1) comprises: a mounting substrate having a first main surface, a second main surface, and a side surface; an electronic component disposed on the first main surface of the mounting substrate; a resin layer covering the first main surface of the mounting substrate and the electronic component; and a metal layer (4) covering the side surface of the mounting substrate and the resin layer. The metal layer (4) has: a third main surface facing the resin layer; and a fourth main surface. The metal layer (4) includes: a side surface section (462) facing the side surface of the mounting substrate; a top surface section (461) facing the first main surface of the mounting substrate; and a connection section (463) connecting the side surface section (462) and the top surface section (461). The metal layer (4) includes: a first metal layer (41) exposed to the outside; and a second metal layer (42) disposed between the first metal layer (41) and the resin layer. The material of the second metal layer (42) has higher ductility than the material of the first metal layer (41). The connection section (463) includes an exposure section at which the second metal layer (42) is exposed to the outside.

Description

High frequency module and communication device

[0001] The present invention relates to a high-frequency module and a communication device, and more particularly to a high-frequency module including a metal layer and a communication device including the high-frequency module.

[0002] Patent Document 1 discloses a module component (high-frequency module) including a circuit board (mounting board), components (electronic components), a sealing portion (resin layer), and a metal film (metal layer). In the module component of Patent Document 1, a chamfered portion is provided at the edge of the boundary where the top surface and side surface of the sealing portion are connected. The metal film of Patent Document 1 has a multi-layer structure and includes a base layer, a copper layer formed on the base layer, and an upper layer provided on the copper layer.

[0003] International Publication No. 2010 / 103756

[0004] However, the module component disclosed in Patent Document 1 has high solder wettability due to the material of the upper layer. Therefore, when the module component disclosed in Patent Document 1 is mounted on a circuit board, excessive solder may adhere to the metal layer, which may cause the module component to crack due to thermal stress. In the module component disclosed in Patent Document 1, there is a possibility that the metal layer may peel off.

[0005] An object of the present invention is to provide a radio frequency module and a communication device with improved reliability.

[0006] A high-frequency module according to one aspect of the present invention includes a mounting substrate, electronic components, external connection terminals, a resin layer, and a metal layer covering the side surfaces of the mounting substrate and the resin layer. The mounting substrate has a first main surface and a second main surface facing each other, and a side surface connecting the first main surface and the second main surface. The electronic components are disposed on the first main surface of the mounting substrate. The external connection terminals are disposed on the second main surface of the mounting substrate. The resin layer covers the first main surface of the mounting substrate and the electronic components. The metal layer has a third main surface and a fourth main surface facing the resin layer. The metal layer includes a side surface portion facing the side surface of the mounting substrate, a top surface portion facing the first main surface of the mounting substrate, and a connection portion connecting the side surface portion and the top surface portion. The metal layer includes a first metal layer and a second metal layer disposed between the first metal layer and the resin layer. The material of the second metal layer is more ductile than the material of the first metal layer, and the connection portion includes an exposed portion where the second metal layer is exposed to the outside.

[0007] A communication device according to one aspect of the present invention includes the high-frequency module and a signal processing circuit connected to the high-frequency module.

[0008] According to the high-frequency module and the communication device according to the above aspect, it is possible to improve reliability.

[0009] FIG. 1 is a perspective view of a high-frequency module according to a first embodiment. FIG. 2 is a cross-sectional view of the high-frequency module, corresponding to the X1-X1 cross section in FIG. 1. FIG. 3 is a partially enlarged view of the high-frequency module according to the first embodiment. FIG. 4 is a circuit configuration diagram of a communication device including the high-frequency module according to the first embodiment. FIG. 5 is a partially enlarged view of a high-frequency module according to a second embodiment. FIG. 6 is a partially enlarged view of a high-frequency module according to a third embodiment. FIG. 7 is a cross-sectional view of a high-frequency module according to a fourth embodiment. FIG. 8 is a cross-sectional view of a high-frequency module according to a fifth embodiment.

[0010] Hereinafter, high-frequency modules and communication devices according to embodiments will be described with reference to the drawings. The drawings referred to in the following embodiments are all schematic diagrams, and the ratios of the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensional ratios.

[0011] (Embodiment 1) (1) High-Frequency Module As shown in FIG. 4 , the high-frequency module 1 is used in, for example, a communication device 100. The communication device 100 is, for example, a mobile phone such as a smartphone. Note that the communication device 100 is not limited to a mobile phone and may be, for example, a wearable device such as a smartwatch. The high-frequency module 1 is a high-frequency module that is compatible with, for example, 4G (fourth generation mobile communication) standards, 5G (fifth generation mobile communication) standards, etc. The 4G standard is, for example, 3GPP (registered trademark, Third Generation Partnership Project) LTE (registered trademark, Long Term Evolution) standards. The 5G standard is, for example, 5G NR (New Radio). The high-frequency module 1 is compatible with, for example, carrier aggregation and dual connectivity.

[0012] (2) Circuit Configuration of High-Frequency Module Hereinafter, the circuit configuration of the high-frequency module 1 according to the first embodiment will be described with reference to FIG.

[0013] 4 , the high-frequency module 1 according to the first embodiment includes a plurality of external connection terminals 10, a switch 110, a first matching circuit 121, a second matching circuit 122, a transmit filter 131, a receive filter 132, a third matching circuit 141, a fourth matching circuit 142, a power amplifier 151, and a low-noise amplifier 152. The plurality of external connection terminals 10 include an antenna terminal 11, a signal input terminal 12, and a signal output terminal 13. Of the high-frequency module 1, the first matching circuit 121, the transmit filter 131, the third matching circuit 141, and the power amplifier 151 are included in the transmit path. Of the high-frequency module 1, the second matching circuit 122, the receive filter 132, the fourth matching circuit 142, and the low-noise amplifier 152 are included in the receive path.

[0014] (2.1) Power Amplifier The power amplifier 151 is an amplifier that amplifies a transmission signal. The power amplifier 151 has an input terminal (not shown) and an output terminal (not shown). The input terminal of the power amplifier 151 is connected to the signal processing circuit 17 via the signal input terminal 12. The output terminal of the power amplifier 151 is connected to the transmission filter 131 via the third matching circuit 141.

[0015] (2.2) Transmit Filter The transmit filter 131 is a filter that passes a transmit signal. The transmit filter 131 is, for example, an acoustic wave filter including multiple series arm resonators and multiple parallel arm resonators. The acoustic wave filter is, for example, a SAW (Surface Acoustic Wave) filter that uses surface acoustic waves. The transmit filter 131 has an input terminal (not shown) and an output terminal (not shown). The input terminal of the transmit filter 131 is connected to the output terminal of the power amplifier 151 via a third matching circuit 141. The output terminal of the transmit filter 131 is connected to the switch 110 via a first matching circuit 121.

[0016] (2.3) Low-Noise Amplifier The low-noise amplifier 152 is an amplifier that amplifies the received signal. The low-noise amplifier 152 has an input terminal (not shown) and an output terminal (not shown). The output terminal of the low-noise amplifier 152 is connected to the signal processing circuit 17 via the signal output terminal 13. The input terminal of the low-noise amplifier 152 is connected to the receive filter 132 via the fourth matching circuit 142.

[0017] (2.4) Receiving Filter The receiving filter 132 is a filter that passes the received signal. The receiving filter 132 is, for example, an acoustic wave filter including multiple series arm resonators and multiple parallel arm resonators. The acoustic wave filter is, for example, a SAW filter that uses surface acoustic waves. The receiving filter 132 has an input terminal (not shown) and an output terminal (not shown). The input terminal of the receiving filter 132 is connected to the switch 110 via the second matching circuit 122. The output terminal of the receiving filter 132 is connected to the input terminal of the low-noise amplifier 152 via the fourth matching circuit 142.

[0018] (2.5) Switch The switch 110 switches between the transmit filter 131 and the receive filter 132 to be connected to the antenna terminal 11. In other words, the switch 110 is a switch for connecting either the receive path or the transmit path to the antenna terminal 11. The switch 110 has a common terminal 111 and multiple (two in the illustrated example) select terminals 112 and 113. The common terminal 111 is connected to the antenna terminal 11. The select terminal 112 is connected to the transmit filter 131 via a first matching circuit 121. The select terminal 113 is connected to the receive filter 132 via a second matching circuit 122.

[0019] (2.6) Matching Circuit The first matching circuit 121 is a circuit for achieving impedance matching between the output terminal of the transmit filter 131 and the selection terminal 112 of the switch 110. The first matching circuit 121 includes at least one of one or more capacitors and one or more inductors.

[0020] The second matching circuit 122 is a circuit for achieving impedance matching between the selection terminal 113 of the switch 110 and the input terminal of the receive filter 132. The second matching circuit 122 includes at least one of one or more capacitors and one or more inductors.

[0021] The third matching circuit 141 is a circuit for achieving impedance matching between the output terminal of the power amplifier 151 and the input terminal of the transmit filter 131. The third matching circuit 141 includes at least one of one or more capacitors and one or more inductors.

[0022] The fourth matching circuit 142 is a circuit for achieving impedance matching between the output terminal of the receive filter 132 and the input terminal of the low-noise amplifier 152. The fourth matching circuit 142 includes at least one of one or more capacitors and one or more inductors.

[0023] (3) Structure of the High-Frequency Module The structure of the high-frequency module 1 according to the first embodiment will be described below with reference to the drawings.

[0024] 1 and 2, the high-frequency module 1 according to the first embodiment includes a mounting substrate 2, a resin layer 3, a metal layer 4, electronic components 51, 52, and a plurality of external connection terminals 10. Note that the dotted hatching in Fig. 1 indicates a portion of the main surface 44 of the metal layer 4 (see Fig. 2) where the second metal layer 42 is exposed, and does not indicate a cross section.

[0025] (3.1) Mounting Board As shown in Fig. 2 , the mounting board 2 has a first main surface 21 and a second main surface 22. The first main surface 21 and the second main surface 22 face each other in a first direction D1, which is the thickness direction of the mounting board 2. The mounting board 2 also has a side surface 23. The side surface 23 connects the first main surface 21 and the second main surface 22.

[0026] 1 and 2, the mounting substrate 2 has a rectangular shape in a plan view from a first direction D1. In the mounting substrate 2, the side surface 23 includes, for example, two portions parallel to a second direction D2 perpendicular to the first direction D1 and two portions parallel to a third direction D3 perpendicular to the first direction D1 and the second direction D2.

[0027] A resin layer 3 , a metal layer 4 , an electronic component 51 , and an electronic component 52 are arranged on a first main surface 21 of the mounting substrate 2 .

[0028] A plurality of external connection terminals 10 are arranged on the second main surface 22 of the mounting substrate 2 .

[0029] The mounting substrate 2 is, for example, a multilayer substrate including multiple dielectric layers and multiple conductive layers. The multiple dielectric layers and multiple conductive layers are stacked in a first direction D1. The multiple conductive layers are formed in a predetermined pattern determined for each layer. Each of the multiple conductive layers includes one or multiple conductor portions in a plane perpendicular to the first direction D1. The material of each conductive layer is, for example, copper. The multiple conductive layers include a ground electrode to which a ground potential is applied. The mounting substrate 2 is, for example, a resin multilayer substrate. The mounting substrate 2 is, for example, selected from a paper phenolic substrate, a paper epoxy substrate, a glass composite substrate, a glass epoxy substrate, and a composite substrate.

[0030] The first main surface 21 and the second main surface 22 of the mounting substrate 2 are separated in the first direction D1 and intersect with the first direction D1. The first main surface 21 of the mounting substrate 2 is, for example, perpendicular to the first direction D1. The second main surface 22 of the mounting substrate 2 is, for example, perpendicular to the first direction D1. The first main surface 21 and the second main surface 22 of the mounting substrate 2 may have minute irregularities, recesses, or protrusions.

[0031] Furthermore, it is preferable that the ground electrode is exposed on at least a part of the side surface 23 of the mounting substrate 2. This connects the metal layer 4 to the ground electrode, thereby improving the electromagnetic wave shielding effect of the metal layer 4 on the electronic components 51 and 52.

[0032] (3.2) Electronic Components As shown in FIG. 2 , the electronic components 51 are disposed on the first main surface 21 of the mounting substrate 2. The electronic components 51 include elements included in the transmission path of the high-frequency module 1. The electronic components 51 are, for example, transmission filters 131.

[0033] The electronic component 51 is, for example, flip-chip mounted on the first main surface 21 of the mounting substrate 2. The electronic component 51 is connected to the mounting substrate 2 by, for example, a plurality of conductive bumps. The conductive bumps are made of, for example, solder, gold, or copper.

[0034] 2 , the electronic component 52 is disposed on the first main surface 21 of the mounting substrate 2. The electronic component 51 includes an element included in the reception path of the high-frequency module 1. The electronic component 51 is, for example, a chip inductor included in the fourth matching circuit 142.

[0035] The electronic component 52 is, for example, flip-chip mounted on the first main surface 21 of the mounting substrate 2. The electronic component 52 is connected to the mounting substrate 2 by, for example, a plurality of conductive bumps. The conductive bumps are made of, for example, solder, gold, or copper.

[0036] Each of the electronic component 51 and the electronic component 52 corresponds to the electronic component of the present disclosure.

[0037] (3.3) External Connection Terminals The plurality of external connection terminals 10 are terminals for electrically connecting the mounting substrate 2 to an external substrate (not shown).

[0038] As shown in FIG. 2 , the plurality of external connection terminals 10 are arranged on the second main surface 22 of the mounting substrate 2. The phrase "the external connection terminals 10 are arranged on the second main surface 22 of the mounting substrate 2" means that the external connection terminals 10 are mechanically connected to the second main surface 22 of the mounting substrate 2 and that the external connection terminals 10 are electrically connected to (appropriate conductor portions of) the mounting substrate 2. The material of the plurality of external connection terminals 10 is, for example, a metal (e.g., copper, copper alloy, etc.). Each of the plurality of external connection terminals 10 is a columnar electrode. The columnar electrode is joined to the conductor portion of the mounting substrate 2, for example, by solder, but is not limited thereto. For example, the columnar electrode may be joined using a conductive adhesive (e.g., a conductive paste) or directly.

[0039] (3.4) Resin Layer As shown in FIG. 2 , the resin layer 3 is disposed on the first main surface 21 of the mounting substrate 2. The resin layer 3 covers the electronic components 51 and 52. The resin layer 3 also covers a portion of the first main surface 21 of the mounting substrate 2 on which the electronic components 51 and 52 are not disposed. In other words, the resin layer 3 covers the first main surface 21 of the mounting substrate 2 and the electronic components 51 and 52.

[0040] The resin layer 3 includes, for example, an epoxy resin and a filler.

[0041] (3.5) Metal Layer As shown in Fig. 2, the metal layer 4 covers the side surface 23 of the mounting substrate 2. The metal layer 4 also covers the resin layer 3. The metal layer 4 covers a main surface 31 of the resin layer 3 opposite to the mounting substrate 2, an outer peripheral surface 32 of the resin layer 3, and the side surface 23 of the mounting substrate 2. The metal layer 4 has the effect of protecting the electronic components 51 and 52 from impact and shielding electromagnetic waves, for example.

[0042] The metal layer 4 has, for example, a rectangular parallelepiped shape with one end in the first direction D1 open. The metal layer 4 includes a top surface portion 461 facing the first main surface 21 of the mounting substrate 2, a side surface portion 462 facing the side surface 23 of the mounting substrate 2, and a connection portion 463 connecting the top surface portion 461 and the side surface portion 462. More specifically, the top surface portion 461 of the metal layer 4 is a rectangular portion whose thickness direction is the first direction D1. The side surface portion 462 of the metal layer 4 is formed along the side surface 23 of the mounting substrate 2. The side surface portion 462 includes a plurality of flat portions 466. The plurality of flat portions 466 are rectangular portions and include two flat surfaces 466 whose thickness direction is the second direction D2 and two flat surfaces 466 whose thickness direction is the third direction D3. The connection portion 463 is provided along the outer periphery of the top surface portion 461.

[0043] The metal layer 4 has a main surface 44 and a main surface 45. The main surface 45 of the metal layer 4 faces the resin layer 3. The main surface 44 of the metal layer 4 is exposed to the outside.

[0044] The metal layer 4 has a multilayer structure in which a plurality of metal layers are stacked. More specifically, as shown in Fig. 2, the metal layer 4 includes a first metal layer 41, a second metal layer 42, and a third metal layer 43. In the metal layer 4, the third metal layer 43, the second metal layer 42, and the first metal layer 41 are stacked in this order from the side closest to the resin layer 3.

[0045] The first metal layer 41 is exposed to the outside and is, for example, a corrosion-resistant layer for reducing oxidation and corrosion of the second metal layer 42. The material of the first metal layer 41 has higher corrosion resistance than the material of the second metal layer 42. Furthermore, it is preferable that the material of the second metal layer 42 has lower solder wettability than the material of the first metal layer 41.

[0046] The material of the first metal layer 41 is selected from, for example, stainless steel and titanium. In the high-frequency module 1 according to the first embodiment, the material of the first metal layer 41 is stainless steel. This makes it possible to improve the corrosion resistance of the metal layer 4 even when the corrosion resistance of the second metal layer 42 is not high.

[0047] The second metal layer 42 is, for example, a conductive layer for reducing the influence of electromagnetic waves on the electronic components 51 and 52. The second metal layer 42 is disposed between the first metal layer 41 and the resin layer 3.

[0048] The material of the second metal layer 42 is more ductile than the material of the first metal layer 41. Here, "the material of the second metal layer 42 is more ductile than the material of the first metal layer 41" means, for example, that when a uniaxial tensile test is performed on each of the materials of the second metal layer 42 and the first metal layer 41, the fracture strain of the material of the second metal layer 42 is greater than that of the material of the first metal layer 41. Also, "the material of the second metal layer 42 is more ductile than the material of the first metal layer 41" means, for example, that when a uniaxial tensile test is performed on each of the materials of the second metal layer 42 and the first metal layer 41, the reduction of area of ​​the material of the second metal layer 42 is greater than that of the material of the first metal layer 41. In other words, "the material of the second metal layer 42 is more ductile than the material of the first metal layer 41" means that when a tensile stress is applied, the second metal layer 42 is less likely to fracture than the first metal layer 41. As a result, even if a crack or the like occurs in the first metal layer 41, the second metal layer 42 is less likely to break, and the impact resistance of the metal layer 4 can be improved.

[0049] The material of the second metal layer 42 is, for example, a metal selected from copper, silver, gold, aluminum, and iron, or an alloy containing a metal. In the high-frequency module 1 according to the first embodiment, the material of the second metal layer 42 is copper. The high conductivity of the material of the second metal layer 42 improves the electromagnetic wave shielding effect of the metal layer 4. Furthermore, the material of the second metal layer 42 has lower solder wettability than the material of the first metal layer 41, making it possible to reduce excessive solder wetting of the main surface 44 of the metal layer 4.

[0050] The third metal layer 43 is, for example, an adhesion layer for improving the adhesion between the resin layer 3 and the second metal layer 42. The material of the third metal layer 43 is selected from, for example, stainless steel and titanium. In the high-frequency module 1 according to the first embodiment, the material of the third metal layer 43 is stainless steel. This makes it possible to improve the adhesion between the metal layer 4 and the resin layer 3 even when the adhesion between the material of the second metal layer 42 and the material of the resin layer 3 is not high. The third metal layer 43 is disposed between the second metal layer 42 and the resin layer 3. More specifically, the third metal layer 43 is in contact with the main surface 31 and the outer peripheral surface 32 of the resin layer 3 and the side surface 23 of the mounting substrate 2.

[0051] As shown in FIGS. 1 and 3 , in the connection portion 463 of the metal layer 4, the main surface 44 includes an exposed portion 441 where the second metal layer 42 is exposed. More specifically, in the main surface 44 of the metal layer 4, the connection portion 463 between the top surface portion 461 and one side surface portion 462 includes the exposed portion 441 and a portion where the first metal layer 41 covers the second metal layer 42. The exposed portion 441 extends, for example, in the second direction D2 or the third direction D3. Therefore, when solder comes into contact with the main surface 44 of the metal layer 4, the exposed portion 441 and the portion where the first metal layer 41 covers the second metal layer 42 have different wettability. This makes it possible to reduce the phenomenon of excessive solder wetting and spreading on the main surface 44 of the metal layer 4. Furthermore, since the film thickness of the first metal layer 41 is not uniform at the connection portion 463 of the metal layer 4, when the thermal expansion coefficients of the material of the first metal layer 41 and the material of the second metal layer 42 are different, thermal stress is less likely to concentrate at the connection portion 463 of the metal layer 4. Therefore, it is possible to reduce the occurrence of peeling of the first metal layer 41 from the second metal layer 42 in the metal layer 4.

[0052] In the metal layer 4, the main surface 44 includes exposed portions 441 between any one flat portion 466 of the side surface portions 462 of the connection portion 463 and the top surface portion 461. That is, the multiple exposed portions 441 are arranged along the outer periphery of the top surface portion 461. This makes it less likely that the exposed portions of the second metal layer 42 will be unevenly distributed on the main surface 44 of the connection portion 463 of the metal layer 4.

[0053] In the metal layer 4, at a connection portion 464 (see FIG. 1 ) between two of the side surface portions 462, the main surface 44 may include a portion where the second metal layer 42 is exposed from the first metal layer 41. This makes it possible to reduce the phenomenon in which the wettability of the solder becomes excessively high on the main surface 44 of the metal layer 4.

[0054] As shown in FIG. 2 , the metal layer 4 has a bent portion 47 at the connection portion 463 on the side opposite the resin layer 3. The bent portion 47 has an arc-shaped cross-section at a cross section intersecting the top surface portion 461 and one of the flat portions 466. Note that the bent portion 47 is omitted in FIG. 3 . This prevents the metal layer 4 from having sharp edges at the connection portion 463. This reduces the risk of chipping of the high-frequency modules 1 due to collisions between the high-frequency modules 1 during transportation of multiple high-frequency modules 1. Furthermore, since the metal layer 4 does not have sharp edges, electric field concentration is less likely to occur in the metal layer 4, thereby reducing the impact of the metal layer 4 on electronic components 51 and the like. The cross section of the bent portion 47 is, for example, arc-shaped with a radius of 5 μm or less.

[0055] Furthermore, the bent portion of the metal layer 4 at the vertex 465 connecting the side surface portions 462 and the top surface portion 461 is spherical. Here, the radius of the cross section of the bent portion 47 at the vertex 465 is equal to or greater than the radius of the cross section of the bent portion 47 at the side portions 467 (see FIG. 3 ) other than the vertex 465. This makes it less likely that the metal layer 4 will be deformed or chipped due to collision with other high-frequency modules 1 when multiple high-frequency modules 1 are transported.

[0056] Here, the exposed portions 441 and the portions where the first metal layer 41 covers the second metal layer 42 are preferably arranged alternately in the second direction D2 or the third direction D3. Furthermore, the area occupied by the exposed portions 441 in the connection portion 463 is preferably 40% or less. This makes it possible to reduce deterioration of the metal layer 4 due to oxidation and corrosion caused by excessive exposure of the second metal layer 42. It also makes it possible to reduce the occurrence of peeling of the first metal layer 41 from the second metal layer 42.

[0057] The bent portion 47 of the metal layer 4 includes an exposed portion 441 and a portion where the first metal layer 41 covers the second metal layer 42. That is, the exposed portions 441 and the portion where the first metal layer 41 covers the second metal layer 42 are alternately arranged in the second direction D2 or the third direction D3 in the bent portion 47 of the metal layer 4. This makes it possible to reduce the phenomenon of the first metal layer 41 peeling off from the second metal layer 42. Furthermore, by polishing the material of the metal layer 4 where the bent portion 47 is not formed, it is possible to simultaneously form the bent portion 47 and the exposed portion 441 of the second metal layer 42, thereby facilitating the manufacture of the metal layer 4.

[0058] (4) Manufacturing Method A manufacturing method for the high-frequency module 1 according to the first embodiment will be described below.

[0059] First, prepare a substrate that will be the material for the mounting substrate 2. The substrate is, for example, a single resin multilayer substrate in which a plurality of mounting substrates 2 are connected in the second direction D2 and the third direction D3.

[0060] Next, electronic components 51, 52, and external connection terminals 10 are mounted on the main surfaces of the substrate. Specifically, electronic components 51 and 52 are mounted on one of the two main surfaces of the substrate. Furthermore, external connection terminals 10 are mounted on the other of the two main surfaces of the substrate.

[0061] Next, the resin layer 3 is formed. The resin layer 3 is formed, for example, by a transfer molding method. More specifically, after plasma cleaning of the substrate, a mold is pressed against one of the two main surfaces of the substrate on which the electronic components 51 and 52 are mounted, and molten material for the resin layer 3 is poured between the mold and the substrate. The surface roughness of the mold is, for example, Ra of 2 μm or more and 20 μm or less. Alternatively, the substrate and the mold may be aligned by inserting alignment pins of the mold into alignment holes previously formed in the substrate. Furthermore, after the resin layer 3 is formed, bumps may be provided on the external connection terminals 10. The bumps are formed, for example, by solder printing. The bump height is, for example, 30 μm or more and 120 μm or less.

[0062] Next, the substrate is cut to form the mounting substrate 2. Specifically, the substrate is cut using a dicer or a laser cutter to form the mounting substrate 2.

[0063] Next, the metal layer 4 is formed. The metal layer 4 is produced, for example, by stacking the material of the metal layer 4 by sputtering and then polishing the material of the metal layer 4. In the sputtering, the material of the third metal layer 43, the material of the second metal layer 42, and the material of the first metal layer 41 are deposited in this order on the side surface 23 of the mounting substrate 2 and the resin layer 3. Then, the position of the metal layer 4 that will become the connection portion 463 is polished to form the bent portion 47, and the exposed portion 441 is formed in part of the bent portion 47. The polishing may be performed by either a dry process or a wet process.

[0064] Through the above manufacturing method, the high frequency module 1 is produced.

[0065] (5) Communication Device As shown in FIG. 4 , the communication device 100 includes the high-frequency module 1, a signal processing circuit 17, and an antenna 16.

[0066] The antenna 16 is connected to the antenna terminal 11 of the high-frequency module 1. The antenna 16 has a transmitting function of emitting a transmission signal output from the high-frequency module 1 as radio waves, and a receiving function of receiving a reception signal from outside as radio waves and outputting it to the high-frequency module 1.

[0067] The signal processing circuit 17 includes an RF signal processing circuit 171 and a baseband signal processing circuit 172. The signal processing circuit 17 processes signals passing through the high-frequency module 1. More specifically, the signal processing circuit 17 processes transmission signals and reception signals.

[0068] The RF signal processing circuit 171 is, for example, an RFIC (Radio Frequency Integrated Circuit), and performs signal processing on high frequency signals.

[0069] The RF signal processing circuit 171 performs signal processing such as up-conversion and amplification on the transmission signal transmitted from the baseband signal processing circuit 172, and outputs the processed transmission signal to the high-frequency module 1. The RF signal processing circuit 171 also performs signal processing such as amplification and down-conversion on the reception signal output from the high-frequency module 1, and outputs the processed reception signal to the baseband signal processing circuit 172.

[0070] The baseband signal processing circuit 172 is, for example, a baseband integrated circuit (BBIC). The baseband signal processing circuit 172 performs predetermined signal processing on a transmission signal from outside the signal processing circuit 17. The received signal processed by the baseband signal processing circuit 172 is used, for example, as an image signal for image display or as an audio signal for telephone calls.

[0071] The RF signal processing circuit 171 also functions as a control unit that controls the connection of the switch 110 of the high-frequency module 1 based on the transmission and reception of high-frequency signals (transmission signal, reception signal). Specifically, the RF signal processing circuit 171 switches the connection of the switch 110 of the high-frequency module 1 using a control signal (not shown). The control unit may be provided outside the RF signal processing circuit 171, and may be provided in the high-frequency module 1 or the baseband signal processing circuit 172, for example.

[0072] (6) Effects The high-frequency module 1 according to the first embodiment includes a mounting substrate 2, electronic components 51 and 52, an external connection terminal 10, a resin layer 3, and a metal layer 4. The mounting substrate 2 has a first main surface 21 and a second main surface 22 that face each other, and a side surface 23 that connects the first main surface 21 and the second main surface 22. The electronic components 51 and 52 are disposed on the first main surface 21 of the mounting substrate 2. The external connection terminal 10 is disposed on the second main surface 22 of the mounting substrate 2. The resin layer 3 covers the first main surface 21 and the electronic components 51 and 52 of the mounting substrate 2. The metal layer 4 covers the side surface 23 of the mounting substrate 2 and the resin layer 3. The metal layer 4 has a third main surface 45 that faces the resin layer 3, and a fourth main surface 44. The metal layer 4 includes a side portion 462 facing the side surface 23 of the mounting substrate 2, a top surface portion 461 facing the first main surface 21 of the mounting substrate 2, and a connection portion 463 connecting the side surface portion 462 and the top surface portion 461. The metal layer 4 includes a first metal layer 41 exposed to the outside and a second metal layer 42 disposed between the first metal layer 41 and the resin layer 3. The material of the second metal layer 42 is more ductile than the material of the first metal layer 41. The connection portion 463 includes an exposed portion 441 where the second metal layer 42 is exposed to the outside. This makes it possible to reduce excessive spreading of the solder because the wettability of the fourth main surface 44 of the metal layer 4 is not uniform at least in the connection portion 463. Furthermore, since the film thickness of the first metal layer 41 is not uniform at the connection portion 463 of the metal layer 4, thermal stress is less likely to concentrate at the connection portion 463 of the metal layer 4, making it possible to reduce peeling of the first metal layer 41 from the second metal layer 42.

[0073] Furthermore, in the radio-frequency module 1 according to the first embodiment, the connection portion 463 of the metal layer 4 has a bent portion 47 on the side opposite to the resin layer 3. This makes it less likely for the metal layer 4 to be deformed or chipped due to collision with other radio-frequency modules 1 when multiple radio-frequency modules 1 are transported. Furthermore, because electric field concentration is less likely to occur in the metal layer 4, it is possible to improve the noise resistance of the radio-frequency module 1.

[0074] Furthermore, in the high-frequency module 1 according to the first embodiment, the cross section of the bent portion 47 at the connection portion 463 of the metal layer 4 is arc-shaped with a radius of 5 μm or less, which can reduce the formation of protrusions on the metal layer 4. It can also reduce the exposure of the resin layer 3 due to the metal layer 4 being too thin.

[0075] Furthermore, in the radio-frequency module 1 according to the first embodiment, the side surface portion 462 of the metal layer 4 includes a plurality of flat surfaces 466. In the connection portion 463, the radius of the cross section of the bent portion 47 at the vertex 465 that connects the top surface portion 461 to two of the plurality of flat surfaces 466 is equal to or greater than the radius of the cross section of the bent portion 47 at the side portion 467 that connects the top surface portion 461 to one of the plurality of flat surfaces 466. This makes it possible to reduce the formation of protrusions on the metal layer 4.

[0076] Furthermore, in the high-frequency module 1 according to the first embodiment, the bent portion 47 includes a portion where the first metal layer 41 covers the second metal layer, and an exposed portion 441. This reduces the phenomenon in which the first metal layer 41 peels off from the second metal layer 42. Furthermore, by polishing the material of the metal layer 4 where the bent portion 47 is not formed, the bent portion 47 and the exposed portion 441 can be formed simultaneously, which facilitates the manufacture of the metal layer 4.

[0077] Furthermore, in the radio-frequency module 1 according to the first embodiment, the side surface portion 462 of the metal layer 4 includes a plurality of flat portions 466. The main surface 44 of the metal layer 4 includes an exposed portion 441 in a portion of the connection portion 463 that connects the top surface portion 461 to any one of the plurality of flat portions 466. This makes it possible to reduce uneven distribution of the exposed portion 441 on the main surface 44 of the connection portion 463 of the metal layer 4.

[0078] Furthermore, in the high-frequency module 1 according to the first embodiment, the metal layer 4 functions as a shield electrode that reduces electromagnetic waves reaching the electronic components 51 and 52. This makes it possible to improve the noise resistance of the high-frequency module 1.

[0079] In the high-frequency module 1 according to the first embodiment, the material of the first metal layer 41 includes stainless steel or titanium. The material of the second metal layer 42 includes copper. This improves the electromagnetic shielding effect of the second metal layer 42 and prevents the solder wettability on the main surface 44 of the metal layer 4 from becoming excessively high. Furthermore, the presence of the first metal layer 41 makes it possible to reduce oxidation of the second metal layer 42.

[0080] The communication device 100 according to the first embodiment also includes the high-frequency module 1 and a signal processing circuit 17 connected to the high-frequency module 1. This allows the communication device 100 to improve the reliability of the metal layer 4 of the high-frequency module 1.

[0081] Second Embodiment In a high-frequency module 1 according to a second embodiment, as shown in FIG. 5, the shape of the exposed portion 441 of the second metal layer 42 at the connection portion 463 of the metal layer 4 is different from that of the high-frequency module 1 according to the first embodiment.

[0082] 5 , in the connection portion 463 of the metal layer 4, the exposed portion 441 of the second metal layer 42 is elongated in a direction intersecting the second direction D2, which further reduces the wettability of the solder on the main surface 44 of the metal layer 4. Note that the exposed portion 441 of the second metal layer 42 includes a portion that is elongated in a direction intersecting the third direction D3.

[0083] Third Embodiment In a high-frequency module 1 according to a third embodiment, as shown in FIG. 6, the shape of the exposed portion 441 of the second metal layer 42 at the connection portion 463 of the metal layer 4 is different from that of the high-frequency module 1 according to the first embodiment.

[0084] 6, in the connection portion 463 of the metal layer 4, the exposed portion 441 of the second metal layer 42 is elongated in a direction intersecting the second direction D2. Furthermore, on the main surface 44 of the metal layer 4, the shape of the outer periphery of the exposed portion 441 of the second metal layer 42 may be any shape and does not have to be smooth as shown in FIG. 6. This further reduces the wettability of the solder on the main surface 44 of the metal layer 4.

[0085] Fourth Embodiment (1) Configuration In a high-frequency module 1 a according to the fourth embodiment, the resin layer 3 has a bent portion 35 in a portion facing the connection portion 463 of the metal layer 4 .

[0086] 7 , in the high-frequency module 1a according to the fourth embodiment, the resin layer 3 has a connection portion 33 that connects the main surface 31 and the outer peripheral surface 32. The connection portion 33 of the resin layer 3 faces the connection portion 463 of the metal layer 4. The connection portion 33 of the resin layer 3 includes a bent portion 35. The bent portion 35 has, for example, an arc-shaped cross section in a cross section intersecting the main surface 31 and the outer peripheral surface 32.

[0087] In the high-frequency module 1a according to the fourth embodiment, the resin layer 3 has a bent portion 35, so that the main surface 45 of the metal layer 4 has a smooth shape. Therefore, the main surface 44 of the metal layer 4 has a smoother shape than the high-frequency module 1 according to the first embodiment. Therefore, in the high-frequency module 1a, damage to the metal layer 4 can be further reduced when multiple high-frequency modules 1a are transported. Furthermore, when the exposed portion 441 of the second metal layer 42 is formed by polishing, the thickness of the metal layer 4 does not become excessively thin.

[0088] (2) Effects In the radio-frequency module 1a according to the fourth embodiment, the resin layer 3 has a bent portion 35 at a portion facing the connection portion 463 of the metal layer 4. This makes it possible to further reduce damage to the metal layer 4 when transporting a plurality of radio-frequency modules 1a. Furthermore, when the exposed portion 441 of the second metal layer 42 is formed by polishing, the thickness of the metal layer 4 is not excessively reduced.

[0089] Fifth Embodiment (1) Configuration In a high-frequency module 1 b according to the fifth embodiment, the connection portion 463 of the metal layer 4 includes the portion 34 where the resin layer 3 is exposed from the metal layer 4 .

[0090] In the radio-frequency module 1b according to the fifth embodiment, a portion 34 of the resin layer 3 is exposed on the main surface 44 at the connection portion 463 of the metal layer 4. This configuration also makes it possible to further reduce damage to the metal layer 4 of the radio-frequency module 1a when transporting a plurality of radio-frequency modules 1a. Furthermore, because the connection portion 463 of the metal layer 4 has a portion where the thickness of the metal layer 4 is zero, there is no need to thicken the metal layer 4.

[0091] (2) Effects In the radio-frequency module 1b according to the fifth embodiment, the connection portion 463 of the metal layer 4 includes a portion where the resin layer 3 is exposed from the metal layer 4. This configuration also makes it possible to further reduce damage to the metal layer 4 of the radio-frequency module 1a when transporting a plurality of radio-frequency modules 1a. Furthermore, because the connection portion 463 of the metal layer 4 has a portion where the thickness of the metal layer 4 is zero, there is no need to thicken the metal layer 4.

[0092] (Modifications) Modifications of the embodiment will be described below.

[0093] In the high-frequency modules 1, 1a, and 1b according to embodiments 1 to 5, the mounting substrate 2 is a resin multilayer substrate, but the mounting substrate 2 may also be, for example, a low-temperature co-fired ceramics (LTCC) substrate, a printed wiring board, or a high-temperature co-fired ceramics (HTCC) substrate.

[0094] Furthermore, the mounting substrate 2 is not limited to a resin multilayer substrate, and may be, for example, a wiring structure. The wiring structure is, for example, a multilayer structure. The multilayer structure includes at least one insulating layer and at least one conductive layer. The insulating layer is formed in a predetermined pattern. When there are multiple insulating layers, the multiple insulating layers are formed in a predetermined pattern defined for each layer. The conductive layer is formed in a predetermined pattern different from the predetermined pattern of the insulating layer. When there are multiple conductive layers, the multiple conductive layers are formed in a predetermined pattern defined for each layer. The conductive layer may include one or more rewiring portions. In the wiring structure, the multilayer structure has two surfaces facing each other in the thickness direction, of which the first surface is the first main surface 21 of the mounting substrate 2 and the second surface is the second main surface 22 of the mounting substrate 2. The wiring structure may be, for example, an interposer. The interposer may be an interposer using a silicon substrate or a substrate configured of multiple layers.

[0095] In the high-frequency modules 1, 1a, and 1b according to the first to fifth embodiments, the third metal layer 43 of the metal layer 4 is not essential, and the second metal layer 42 may be in contact with the resin layer 3. Furthermore, the metal layer 4 may have two or more layers between the second metal layer 42 and the resin layer 3.

[0096] The high-frequency modules 1, 1a, and 1b according to the first to fifth embodiments do not need to have both a transmission path and a reception path, and may have either a transmission path or a reception path. Furthermore, the high-frequency modules 1, 1a, and 1b according to the first to fifth embodiments may have multiple transmission paths or multiple reception paths.

[0097] (Summary) A high-frequency module (1; 1a; 1b) according to a first aspect includes a mounting substrate (2), electronic components (51, 52), an external connection terminal (10), a resin layer (3), and a metal layer (4). The mounting substrate (2) has a first main surface (21) and a second main surface (22) facing each other, and a side surface (23) connecting the first main surface (21) and the second main surface (22). The electronic components (51, 52) are disposed on the first main surface (21) of the mounting substrate (2). The external connection terminal (10) is disposed on the second main surface (22) of the mounting substrate (2). The resin layer (3) covers the first main surface (21) and the electronic components (51, 52) of the mounting substrate (2). The metal layer (4) covers the side surface (23) of the mounting substrate (2) and the resin layer (3). The metal layer (4) has a third main surface (45) facing the resin layer (3) and a fourth main surface (44). The metal layer (4) includes a side portion (462) facing the side surface (23) of the mounting substrate (2), a top surface portion (461) facing the first main surface (21) of the mounting substrate (2), and a connection portion (463) connecting the side portion (462) and the top surface portion (461). The metal layer (4) includes a first metal layer (41) exposed to the outside and a second metal layer (42) disposed between the first metal layer (41) and the resin layer (3). The material of the second metal layer (42) is more ductile than the material of the first metal layer (41). The connection portion (463) includes an exposed portion (441) where the second metal layer (42) is exposed to the outside.

[0098] According to the high-frequency module (1; 1a; 1b) of the above aspect, excessive spreading of the solder can be reduced because the wettability of the fourth main surface (44) of the metal layer (4) to the solder is not uniform at least at the connection portion (463). Also, because the film thickness of the first metal layer (41) is not uniform at the connection portion (463) of the metal layer (4), thermal stress is less likely to concentrate at the connection portion (463) of the metal layer (4), and peeling of the first metal layer (41) from the second metal layer (42) can be reduced.

[0099] In the high-frequency module (1; 1a; 1b) according to the second aspect, in the first aspect, the connection portion (463) of the metal layer (4) has a bent portion (47) on the side opposite to the resin layer (3).

[0100] According to the high-frequency module (1; 1a; 1b) of the above aspect, when a plurality of high-frequency modules (1; 1a; 1b) are transported, the metal layer (4) is less likely to be deformed or chipped due to collision with other high-frequency modules (1; 1a; 1b). Furthermore, since electric field concentration is less likely to occur in the metal layer (4), it is possible to improve the noise resistance of the high-frequency module (1; 1a; 1b).

[0101] In the high frequency module (1a) according to the third aspect, in the second aspect, the resin layer (3) has a bent portion (35) in a portion facing the connection portion (463) of the metal layer (4).

[0102] According to the high-frequency module (1 a) of the above aspect, it is possible to further reduce damage to the metal layer (4) when transporting a plurality of high-frequency modules (1 a). Furthermore, when the exposed portion (441) of the second metal layer (42) is formed by polishing, the thickness of the metal layer (4) is not excessively reduced.

[0103] In the high frequency module (1b) according to the fourth aspect, in the second aspect, the connection portion (463) of the metal layer (4) includes a portion (34) where the resin layer (3) is exposed.

[0104] According to the high-frequency module (1b) of the above aspect, it is possible to further reduce damage to the metal layer (4) when transporting a plurality of high-frequency modules (1b). In addition, since the thickness of the metal layer (4) is zero at the connection portion (463) of the metal layer (4), there is no need to thicken the metal layer (4).

[0105] In the high-frequency module (1; 1a; 1b) according to the fifth aspect, in any of the second to fourth aspects, the cross section of the bent portion (47) at the connection portion (463) of the metal layer (4) is arc-shaped with a radius of 5 μm or less.

[0106] The high-frequency module (1; 1a; 1b) according to the above-described embodiment can reduce the formation of protrusions on the metal layer (4) and can also reduce exposure of the resin layer (3) due to the metal layer (4) being too thin.

[0107] In a radio-frequency module (1; 1a; 1b) according to a sixth aspect, in any of the second to fifth aspects, the side portion (462) of the metal layer (4) includes a plurality of flat portions (466). The radius of the cross section of the bent portion (47) at the vertex (465) of the connection portion (463) connecting the top surface portion (461) and two of the plurality of flat portions (466) is equal to or greater than the radius of the cross section of the bent portion (47) at the side portion (467) connecting the top surface portion (461) and one of the plurality of flat portions (466).

[0108] According to the high-frequency module (1; 1a; 1b) of the above aspect, it is possible to reduce the formation of protrusions on the metal layer (4).

[0109] In the high-frequency module (1; 1a; 1b) according to the seventh aspect, in any of the second to sixth aspects, the bent portion (47) of the metal layer (4) includes a portion where the first metal layer (41) covers the second metal layer (42) and an exposed portion (441).

[0110] The high-frequency module (1; 1a; 1b) according to the above aspect can reduce the phenomenon of the first metal layer (41) peeling off from the second metal layer (42). Furthermore, by polishing the material of the metal layer (4) where the bent portion (47) is not formed, the bent portion (47) and the exposed portion (441) of the second metal layer (42) can be formed simultaneously, which makes it easier to manufacture the metal layer (4).

[0111] In a high-frequency module (1; 1a; 1b) according to an eighth aspect, in any of the first to seventh aspects, the side portion (462) of the metal layer (4) has a plurality of flat portions (466). The fourth main surface (44) of the metal layer (4) includes an exposed portion (441) in a portion of the connection portion (463) that connects the top surface portion (461) and any one of the plurality of flat portions (466).

[0112] According to the high-frequency module (1; 1a; 1b) of the above aspect, it is possible to reduce uneven distribution of the exposed portion (441) on the fourth main surface (44) of the connection portion (463) of the metal layer (4).

[0113] In a high-frequency module (1; 1a; 1b) according to a ninth aspect, in any one of the first to eighth aspects, the metal layer (4) functions as a shield electrode.

[0114] According to the high-frequency module (1; 1a; 1b) of the above aspect, the metal layer (4) functions as a shield electrode that reduces electromagnetic waves reaching the electronic components (51, 52), thereby improving the noise resistance of the high-frequency module (1; 1a; 1b).

[0115] In a high-frequency module (1; 1a; 1b) according to a tenth aspect, in any one of the first to ninth aspects, the material of the first metal layer (41) includes stainless steel or titanium, and the material of the second metal layer (42) includes copper.

[0116] According to the high-frequency module (1; 1a; 1b) of the above aspect, the electromagnetic shielding effect of the second metal layer (42) is improved, and the solder wettability on the fourth main surface (44) of the metal layer (4) is not excessively high. Furthermore, the presence of the first metal layer (41) makes it possible to reduce oxidation of the second metal layer (42).

[0117] A communication device (100) according to an eleventh aspect includes a high-frequency module (1; 1a; 1b) according to any one of the first to tenth aspects, and a signal processing circuit (17) connected to the high-frequency module (1; 1a; 1b).

[0118] According to the communication device (100) of the above aspect, it is possible to improve the reliability of the metal layer (4) of the high frequency module (1; 1a; 1b).

[0119] REFERENCE SIGNS 1, 1a, 1b High frequency module 2 Mounting substrate 21 First main surface 22 Second main surface 23 Side surface 3 Resin layer 31 Main surface 32 Outer peripheral surface 33 Connection portion 34 Part 35 Bent portion 4 Metal layer 41 First metal layer 42 Second metal layer 43 Third metal layer 44 Main surface (fourth main surface) 441 Exposed portion 45 Main surface (third main surface) 461 Top surface portion 462 Side surface portion 463 Connection portion 464 Connection portion 465 Vertex portion 466 Planar portion 467 Side portion 47 Bent portion 51 Electronic component 52 Electronic component 100 Communication device 10 External connection terminal 11 Antenna terminal 12 Signal input terminal 13 Signal output terminal 110 Switch 111 Common terminal 112 Selection terminal 113 Selection terminal 16 Antenna 121 First matching circuit 122 Second matching circuit 131 Transmit filter 132 Receiving filter 141 Third matching circuit 142 Fourth matching circuit 151 Power amplifier 152 Low noise amplifier 17 Signal processing circuit 171 RF signal processing circuit 172 Baseband signal processing circuit D1 First direction D2 Second direction D3 Third direction

Claims

1. A mounting substrate having a first main surface and a second main surface opposing each other and a side surface connecting the first main surface and the second main surface; electronic components arranged on the first main surface of the mounting substrate; external connection terminals arranged on the second main surface of the mounting substrate; a resin layer covering the first main surface of the mounting substrate and the electronic components; and a metal layer covering the side surface of the mounting substrate and the resin layer, wherein the metal layer has a third main surface facing the resin layer and a fourth main surface, the metal layer including: a side portion facing the side surface of the mounting substrate; a top surface portion facing the first main surface of the mounting substrate; and a connection portion connecting the side surface and the top surface, the metal layer including: a first metal layer exposed to the outside; and a second metal layer arranged between the first metal layer and the resin layer, the material of the second metal layer being more ductile than the material of the first metal layer, the connection portion includes an exposed portion where the second metal layer is exposed to the outside.

2. The high frequency module according to claim 1, wherein the connecting portion of the metal layer has a bent portion on the side opposite to the resin layer.

3. The high-frequency module according to claim 2, wherein the resin layer has a bent portion in a portion facing the connection portion of the metal layer.

4. The high-frequency module according to claim 2, wherein the connection portion of the metal layer includes a portion where the resin layer is exposed.

5. The high-frequency module according to any one of claims 2 to 4, wherein the cross section of the bent portion in the connection portion of the metal layer is arc-shaped with a radius of 5 μm or less.

6. A radio frequency module according to any one of claims 2 to 5, wherein the side surface portion of the metal layer includes a plurality of flat surfaces, and the radius of the cross section of the bent portion of the connecting portion at the vertex portion connecting the top surface portion to two of the plurality of flat surfaces is equal to or greater than the radius of the cross section of the bent portion at the side portion connecting the top surface portion to one of the plurality of flat surfaces.

7. The high-frequency module according to any one of claims 2 to 6, wherein the bent portion of the metal layer includes a portion where the first metal layer covers the second metal layer, and the exposed portion.

8. A radio frequency module according to any one of claims 1 to 7, wherein the side surface portion of the metal layer includes a plurality of flat surfaces, and the fourth main surface of the metal layer includes the exposed portion in a portion of the connection portion that connects the top surface portion to any one of the plurality of flat surfaces.

9. The high-frequency module according to any one of claims 1 to 8, wherein the metal layer functions as a shield electrode.

10. The high frequency module according to any one of claims 1 to 9, wherein the material of the first metal layer includes stainless steel or titanium, and the material of the second metal layer includes copper.

11. A communication device comprising: a high-frequency module according to any one of claims 1 to 10; and a signal processing circuit connected to said high-frequency module.

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