Antenna module and resin composition for the antenna module

Abstract

To provide an antenna module capable of obtaining a good antenna characteristic, and provide an electromagnetic wave absorption paste composition for the antenna module.SOLUTION: An antenna module 1 comprises: a wiring substrate 2 having a multi-layer structure; a first antenna; a second antenna; and a semiconductor element 3. Each of the first antenna and the second antenna is overlapped to the first main surface 21 of the wiring substrate 2. The semiconductor element 3 is mounted onto the second main surface 22 of the wiring substrate 2. The first antenna and the semiconductor element 3 are electrically connected with a first via, and the second antenna and the semiconductor element 3 are electrically connected with a second via. An electromagnetic wave absorption via in the wiring substrate 2 contains an electromagnetic wave absorption material. The electromagnetic wave absorption material contains: a hardening material of a thermosetting compound containing at least one kind selected from an epoxy compound, a silicone compound, an acrylic compound, and an urethane resin; and a magnetic iron oxide which carries out magnetic resonance with a frequency of a millimeter wave band or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an antenna module and a resin composition for an antenna module.

Background Art

[0002] In Patent Document 1, in order to reduce noise in a circuit board, a laminated substrate in which a plurality of dielectric layers are laminated is provided on a base material, and a shield via having a maximum peak of electromagnetic wave absorption amount within a 30 to 300 GHz band is provided inside the laminated substrate. It is disclosed. According to Patent Document 1, unnecessary electromagnetic waves generated inside the circuit board can be not only reflected and reduced by the shield via, but also absorbed by the shield via, so that the noise in the circuit board can be reduced accordingly.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to provide an antenna module capable of obtaining good antenna characteristics and an electromagnetic wave absorbing resin composition for an antenna module.

Means for Solving the Problems

[0005] An antenna module according to one aspect of the present disclosure includes a wiring board having a multilayer structure, a first antenna, a second antenna, and a semiconductor element. The wiring board has a first main surface, a second main surface on the side opposite to the first main surface, a first via, a second via, and an electromagnetic wave absorption via. Each of the first antenna and the second antenna overlaps the first main surface. The semiconductor element is mounted on the second main surface. The first antenna and the semiconductor element are electrically connected by the first via, and the second antenna and the semiconductor element are electrically connected by the second via. The electromagnetic wave absorption via contains an electromagnetic wave absorbing material. The electromagnetic wave absorbing material contains a cured product of a thermosetting compound containing at least one selected from the group consisting of an epoxy compound, a silicone compound, an acrylic compound, and a urethane resin, and magnetic iron oxide that magnetically resonates at a frequency of a millimeter wave band or higher.

[0006] A resin composition for an antenna module according to one aspect of the present disclosure is a resin composition for an antenna module for producing an electromagnetic wave absorbing material in an antenna module. The antenna module includes a wiring board having a multilayer structure, a first antenna, a second antenna, and a semiconductor element. The wiring board has a first main surface, a second main surface on the side opposite to the first main surface, a first via, a second via, and an electromagnetic wave absorption via. Each of the first antenna and the second antenna overlaps the first main surface. The semiconductor element is mounted on the second main surface. The first antenna and the semiconductor element are electrically connected by the first via, and the second antenna and the semiconductor element are electrically connected by the second via. The electromagnetic wave absorption via contains the electromagnetic wave absorbing material. The resin composition for an antenna module contains a thermosetting compound containing at least one selected from the group consisting of an epoxy compound, a silicone compound, an acrylic compound, and a urethane resin, and a magnetic iron oxide filler that magnetically resonates at a frequency of a millimeter wave band or higher. The viscosity of the resin composition for an antenna module at 25°C is 50 Pa·s or more and 500 Pa·s or less.

Advantages of the Invention

[0007] According to the present disclosure, an antenna module and a resin composition for an antenna module capable of obtaining good antenna characteristics can be provided.

Brief Description of the Drawings

[0008]

Figure 1

Modes for Carrying Out the Invention

[0009] Embodiments and modified examples will be described with reference to FIG. 1. Note that the following embodiments and modified examples are only a part of various embodiments of the present disclosure. Further, the following embodiments can be variously modified according to design and the like as long as the object of the present disclosure can be achieved. FIG. 1 is a schematic diagram, and the dimensional ratios of the components in the figure do not necessarily reflect the actual dimensional ratios.

[0010] The antenna module 1 according to the embodiment includes a wiring board 2 having a multilayer structure, a first antenna (receiving antenna 4), a second antenna (transmitting antenna 5), and a semiconductor element 3. The wiring board 2 has a first main surface 21, a second main surface 22 on the side opposite to the first main surface 21, a first via (receiving power supply via 7a), a second via (transmitting power supply via 7b), and an electromagnetic wave absorption via (shield via Va). Each of the first antenna and the second antenna overlaps the first main surface 21. The semiconductor element 3 is mounted on the second main surface 22. The first antenna and the semiconductor element 3 are electrically connected by the first via, and the second antenna and the semiconductor element 3 are electrically connected by the second via. The electromagnetic wave absorption via contains an electromagnetic wave absorption material. The electromagnetic wave absorption material contains a cured product of a thermosetting compound containing at least one selected from the group consisting of an epoxy compound, a silicone compound, an acrylic compound, and a urethane resin, and magnetic iron oxide that resonates magnetically at a frequency of the millimeter wave band or higher.

[0011] In the antenna module 1, it is important to have high reliability and good antenna characteristics. In the embodiment, the electromagnetic wave absorbing via can absorb unnecessary electromagnetic waves generated in the wiring board 2, and thus the antenna characteristics can be improved. Therefore, according to the embodiment, an antenna module 1 capable of obtaining good antenna characteristics can be obtained.

[0012] FIG. 1 is a schematic cross-sectional view of the antenna module 1 in the present embodiment. The antenna module 1 includes a wiring board 2, a semiconductor element 3 having a radio frequency integrated circuit (RFIC), a receiving antenna 4 which is a first antenna, and a transmitting antenna 5 which is a second antenna.

[0013] In the case of the present embodiment, the wiring board 2 includes, for example, a base material 6, a laminated board such as a printed wiring board overlapping on the base material 6, and an RF (Radio Frequency) board overlapping on the laminated board. That is, the base material 6, the laminated board, and the RF board are laminated in this order. The laminated board is composed of, for example, a plurality of laminated dielectric layers.

[0014] The material of the base material 6 is not particularly limited. The base material 6 preferably includes a plurality of low dielectric loss dielectric layers and a plurality of conductor foils with high conductivity in order to suppress the attenuation of high-frequency signals, and these dielectric layers and conductor foils are preferably laminated alternately.

[0015] The type of conductor in the conductor foil is not particularly limited as long as it does not impede the purpose of the present disclosure. The conductor is preferably a metal material. As the metal material, at least one selected from the group consisting of aluminum, titanium, stainless steel, copper, brass, silver, gold, and platinum is preferable.

[0016] The dielectric, which is the material of the dielectric layer, is appropriately selected from various dielectrics used for purposes such as electrical insulation in the field of antenna elements, for example. Suitable examples of the dielectric include PTFE and glass fiber-containing epoxy compounds. In each dielectric layer, a plurality of circuit groups with different frequency bands and signal processing methods are formed, such as a power supply circuit for RFIC, a digital circuit, and an analog circuit for baseband signals.

[0017] In the embodiment, the first main surface 21 is the surface on the RF substrate side of the wiring substrate 2, and the second main surface 22 is the surface on the base material 6 side of the wiring substrate 2. That is, the first main surface 21 is the outer surface of the RF substrate, and the second main surface 22 is the outer surface of the base material 6.

[0018] The wiring substrate 2 has a receiving power supply via 7a, which is a first via, and a transmitting power supply via 7b, which is a second via. Each of the receiving power supply via 7a and the transmitting power supply via 7b can function as a signal via.

[0019] Each of the receiving power supply via 7a and the transmitting power supply via 7b penetrates the wiring substrate 2 from the first main surface 21 to the second main surface 22. Two ends of the receiving power supply via 7a are exposed on the first main surface 21 and the second main surface 22, respectively, and two ends of the transmitting power supply via 7b are exposed on the first main surface 21 and the second main surface 22, respectively.

[0020] The wiring substrate 2 has a shield via Va, which is an electromagnetic wave absorption via. The shield via Va is cylindrical. The shield via Va is formed in the wiring substrate 2 so as to reach the base material 6 from the first main surface. That is, the shield via Va penetrates the laminated substrate and the RF substrate. One end of the shield via Va is exposed on the first main surface 21.

[0021] In a plan view, the shield via Va is positioned between the receiving power supply via 7a and the transmitting power supply via 7b. The plan view means looking at the antenna module 1 in the direction of the second main surface 22 with respect to the first main surface 21. That is, the receiving power supply via 7a, the shield via Va, and the transmitting power supply via 7b are arranged in this order in one direction along the first main surface 21.

[0022] Each of the receiving antenna 4 and the transmitting antenna 5 overlaps the first main surface 21 on the wiring substrate 2. That is, each of the receiving antenna 4 and the transmitting antenna 5 overlaps the outer surface of the RF substrate. There is a gap between the receiving antenna 4 and the transmitting antenna 5 in one direction along the first main surface 21.

[0023] The receiving antenna 4 is in contact with the end of the receiving power supply via 7a exposed on the first main surface 21, and thus the receiving antenna 4 is electrically connected to the receiving power supply via 7a. The transmitting antenna 5 is in contact with the end of the transmitting power supply via 7b exposed on the first main surface 21, and thus the transmitting antenna 5 is electrically connected to the transmitting power supply via 7b. The shield via Va is not in contact with either the receiving antenna 4 or the transmitting antenna 5.

[0024] The semiconductor element 3 is mounted on the second main surface 22 of the wiring substrate 2, that is, the outer surface of the base material 6. The antenna module 1 includes a joint portion 8a interposed between the semiconductor element 3 and the receiving power supply via 7a, and a joint portion 8b interposed between the semiconductor element 3 and the transmitting power supply via 7b. The semiconductor element 3 and the receiving power supply via 7a are electrically connected via the joint portion 8a, and the semiconductor element 3 and the transmitting power supply via 7b are electrically connected via the joint portion 8b. Each of the joint portion 8a and the joint portion 8b is, for example, a solder bump.

[0025] Therefore, the receiving antenna 4 and the semiconductor element 3 are electrically connected via the receiving power supply via 7a, and the transmitting antenna 5 and the semiconductor element 3 are electrically connected via the transmitting power supply via 7b.

[0026] The operation of the antenna module 1 will be described.

[0027] When the receiving antenna 4 receives millimeter-wave band electromagnetic waves in the external environment, the receiving antenna 4 can send the received signal to the radio frequency integrated circuit of the semiconductor element 3 via the receiving power supply via hole 7a. Further, the semiconductor element 3 sends the millimeter-wave band transmission signal generated by the radio frequency integrated circuit to the transmitting antenna 5 via the transmitting power supply via hole 7b, and the transmitting antenna 5 can transmit millimeter-wave band electromagnetic waves to the external environment.

[0028] When signals in the millimeter-wave band propagate within the wiring board 2 in this way, the electromagnetic wave noise generated between the receiving power supply via hole 7a and the transmitting power supply via hole 7b can be effectively absorbed by the shielding via hole Va.

[0029] Note that the millimeter-wave band in the embodiment is a band of 30 to 300 GHz. In the embodiment, it is preferable that the receiving antenna 4 has a configuration capable of receiving electromagnetic waves having the maximum radio wave peak within the millimeter-wave band, and it is preferable that the transmitting antenna 5 has a configuration capable of transmitting electromagnetic waves having the maximum radio wave peak within the millimeter-wave band.

[0030] Note that the position of the shielding via hole Va is not limited to the embodiment, and it may be at an appropriate position where electromagnetic wave noise can be effectively absorbed.

[0031] The shielding via hole Va will be described in more detail.

[0032] In the embodiment, the shielding via hole Va, which is an electromagnetic wave absorption via hole, contains an electromagnetic wave absorbing material. The electromagnetic wave absorbing material includes a cured product of a thermosetting compound containing at least one selected from the group consisting of epoxy compounds, silicone compounds, acrylic compounds, and urethane resins, and magnetic iron oxide that resonates magnetically at frequencies above the millimeter-wave band.

[0033] The electromagnetic wave absorbing material contained in the shield via Va preferably has a maximum peak of electromagnetic wave absorption in the 30 to 300 GHz band. Although not particularly limited, it is desirable that the magnetic iron oxide in the electromagnetic wave absorbing material particularly contains epsilon-type iron oxide. The shield via Va can have a maximum peak of electromagnetic wave absorption in the 30 to 300 GHz band, for example, depending on the composition of the electromagnetic wave absorbing material.

[0034] The electromagnetic wave absorbing material in the shield via Va can be made from a resin composition for an antenna module. That is, the shield via Va can be made from a resin composition for an antenna module. The resin composition for an antenna module will be described below.

[0035] The resin composition for an antenna module includes a thermosetting compound containing at least one selected from the group consisting of an epoxy compound, a silicone compound, an acrylic compound, and a urethane resin, and a magnetic iron oxide filler that resonates magnetically at a frequency of the millimeter wave band or higher. The viscosity of the resin composition for an antenna module at 25°C is 50 Pa·s or more and 500 Pa·s or less.

[0036] When the resin composition for an antenna module of the embodiment is used, even when the shield via Va is fine, the shield via Va can be sufficiently filled with the electromagnetic wave absorbing material.

[0037] The epoxy compound is a compound having an epoxy group in the molecule. The silicone compound is an organic compound having a siloxane bond in the molecule. The acrylic compound is a compound having at least one of an acryloyl group and a methacryloyl group in the molecule. The urethane resin is a compound that can produce polyurethane by reacting, and contains, for example, a polyisocyanate and a polyol. The thermosetting compound may further contain a curing agent that reacts with any of the above compounds.

[0038] The magnetic iron oxide filler in the resin composition for an antenna module is a filler composed of particles containing magnetic iron oxide. The magnetic iron oxide contains at least one selected from the group consisting of, for example, cubic ferrite, strontium ferrite, and epsilon-type iron oxide.

[0039] Epsilon-type iron oxide is a crystal represented by ε-Fe 2 O 3 , a crystal represented by ε-A x Fe 2-x O 3 (where A is an element other than Fe, and x is in the range of 0 < x < 2), a crystal represented by ε-B y C z Fe 2-y-z O 3 (where B and C here are elements other than A and Fe and are different from each other, y is in the range of 0 < y < 1, and z is in the range of 0 < z < 1), and a crystal represented by ε-D U E V F W Fe 2-U-V-W O 3 (where D, E, and F here are elements other than A and Fe and are different from each other, U is in the range of 0 < U < 1, V is in the range of 0 < V < 1, and W is in the range of 0 < W < 1). It is desirable to contain at least one selected from the group consisting of the crystals.

[0040] The crystal system and space group of ε-A x Fe 2-x O 3 are the same as those of ε-Fe 2 O 3 , and the crystal of ε-Fe 2 O 3 has a structure in which a part of the Fe sites is substituted with an element A other than Fe. To keep the crystal structure of ε-Fe 2 O 3 stable, A is preferably a trivalent element. Further, A is more preferably one element selected from Al, Sc, Ti, V, Cr, Ga, In, Y, and Rh.

[0041] The resin composition for an antenna module may contain only a magnetic iron oxide filler and a thermosetting compound, and may further contain appropriate additives in addition to the magnetic iron oxide filler and the thermosetting compound as needed. The additives include at least one selected from the group consisting of, for example, a dispersant and a coupling agent.

[0042] When the resin composition for an antenna module contains a dispersant, the dispersant can improve the dispersibility of inclusions such as the magnetic iron oxide filler in the resin composition for an antenna module. The dispersant includes at least one selected from the group consisting of, for example, polyester, polyether, phosphate ester, phosphate polyester, alkylamine salt, and alkylammonium salt compound. The amount of the dispersant with respect to 100 parts by mass of the magnetic iron oxide filler is preferably 0.1 part by mass or more and 5.0 parts by mass or less.

[0043] When the resin composition for an antenna module contains a coupling agent, the coupling agent can suppress the aggregation of the magnetic iron oxide filler. The coupling agent includes at least one selected from the group consisting of, for example, a silane coupling material, a titanate coupling material, a zirconate coupling agent, and an aluminate coupling agent. The addition amount is 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the filler.

[0044] (Aspect) The antenna module (1) of the first aspect includes a wiring board (2) having a multilayer structure, a first antenna, a second antenna, and a semiconductor element (3). The wiring board (2) has a first main surface (21), a second main surface (22) on the side opposite to the first main surface (21), a first via, a second via, and an electromagnetic wave absorption via. Each of the first antenna and the second antenna overlaps the first main surface (21). The semiconductor element (3) is mounted on the second main surface (22). The first antenna and the semiconductor element (3) are electrically connected by the first via, and the second antenna and the semiconductor element (3) are electrically connected by the second via. The electromagnetic wave absorption via contains an electromagnetic wave absorbing material. The electromagnetic wave absorbing material contains a cured product of a thermosetting compound containing at least one selected from the group consisting of an epoxy compound, a silicone compound, an acrylic compound, and a urethane resin, and magnetic iron oxide that resonates magnetically at a frequency of the millimeter wave band or higher.

[0045] According to this aspect, the antenna module (1) can obtain good antenna characteristics.

[0046] In the second aspect, in the first aspect, the electromagnetic wave absorption via is located between the first via and the second via in a plan view.

[0047] The resin composition for an antenna module according to the third aspect is a resin composition for an antenna module for producing an electromagnetic wave absorber in the antenna module (1). The antenna module (1) includes a wiring board (2) having a multilayer structure, a first antenna, a second antenna, and a semiconductor element (3). The wiring board (2) has a first main surface (21), a second main surface (22) on the side opposite to the first main surface (21), a first via, a second via, and an electromagnetic wave absorption via. Each of the first antenna and the second antenna overlaps the first main surface. The semiconductor element (3) is mounted on the second main surface (22). The first antenna and the semiconductor element (3) are electrically connected by the first via, and the second antenna and the semiconductor element (3) are electrically connected by the second via. The electromagnetic wave absorption via contains an electromagnetic wave absorber. The resin composition for an antenna module includes a thermosetting compound containing at least one selected from the group consisting of an epoxy compound, a silicone compound, an acrylic compound, and a urethane resin, and a magnetic iron oxide filler that resonates magnetically at a frequency in the millimeter wave band or higher. The viscosity of the resin composition for an antenna module at 25 °C is 50 Pa·s or more and 500 Pa·s or less.

[0048] In the fourth aspect, in the third aspect, the magnetic iron oxide filler contains epsilon-type iron oxide.

[0049] In the fifth aspect, in the third or fourth aspect, the amount of the magnetic iron oxide filler with respect to 100 parts by mass of the thermosetting compound is 150 parts by mass or more and 260 parts by mass or less.

[0050] In the sixth aspect, in any one of the third to fifth aspects, the resin composition for an antenna module further contains a dispersant. The amount of the dispersant with respect to 100 parts by mass of the magnetic iron oxide filler is 0.1 part by mass or more and 5.0 parts by mass or less. The dispersant contains at least one selected from the group consisting of a polyester, a polyether, a phosphate ester, a phosphate polyester, an alkylamine salt, and an alkylammonium salt compound.

[0051] In the seventh aspect, in any one of the third to sixth aspects, the resin composition for an antenna module further contains a coupling agent. The amount of the coupling agent with respect to 100 parts by mass of the magnetic iron oxide filler is 0.1% by mass or more and 5.0 parts by mass or less. The coupling agent includes at least one selected from the group consisting of a silane coupling material, a titanate coupling material, a zirconate coupling agent, and an aluminate coupling agent.

Explanation of Signs

[0052] 1 Antenna module 2 Wiring board 3 Semiconductor element 4 Receiving antenna (first antenna) 5 Transmitting antenna (second antenna) 6 Base material 7a Receiving power supply via (first via) 7b Transmitting power supply via (second via) 8a Joint part 8b Joint part Va Shield via (electromagnetic wave absorption via)

Claims

1. A wiring board having a multilayer structure, a first antenna, a second antenna, and a semiconductor element, wherein the wiring board has a first main surface, a second main surface on the side opposite to the first main surface, a first via, a second via, and an electromagnetic wave absorbing via, each of the first antenna and the second antenna overlaps the first main surface, the semiconductor element is mounted on the second main surface, the first antenna and the semiconductor element are electrically connected by the first via, and the second antenna and the semiconductor element are electrically connected by the second via, the electromagnetic wave absorbing via contains an electromagnetic wave absorbing material, the electromagnetic wave absorbing material contains a cured product of a thermosetting compound containing at least one selected from the group consisting of an epoxy compound, a silicone compound, an acrylic compound, and a urethane resin, and magnetic iron oxide that resonates magnetically at a frequency of the millimeter wave band or higher, an antenna module.

2. The electromagnetic wave absorbing via is located between the first via and the second via in a plan view, The antenna module according to Claim 1.

3. A resin composition for an antenna module for producing an electromagnetic wave absorbing material in an antenna module, wherein the antenna module has a wiring board having a multilayer structure, a first antenna, a second antenna, and a semiconductor element, the wiring board has a first main surface, a second main surface on the side opposite to the first main surface, a first via, a second via, and an electromagnetic wave absorbing via, each of the first antenna and the second antenna overlaps the first main surface, the semiconductor element is mounted on the second main surface, the first antenna and the semiconductor element are electrically connected by the first via, and the second antenna and the semiconductor element are electrically connected by the second via, the electromagnetic wave absorbing via contains the electromagnetic wave absorbing material, the resin composition for an antenna module contains a thermosetting compound containing at least one selected from the group consisting of an epoxy compound, a silicone compound, an acrylic compound, and a urethane resin, and a magnetic iron oxide filler that resonates magnetically at a frequency of the millimeter wave band or higher, and has a viscosity at 25°C of 50 Pa·s or more and 500 Pa·s or less, a resin composition for an antenna module.

4. The magnetic iron oxide filler contains epsilon-type iron oxide, The resin composition for an antenna module according to claim 3.

5. The amount of the magnetic iron oxide filler with respect to 100 parts by mass of the thermosetting compound is 150 parts by mass or more and 260 parts by mass or less. The resin composition for an antenna module according to claim 3.

6. Further containing a dispersant, The amount of the dispersant with respect to 100 parts by mass of the magnetic iron oxide filler is 0.1 part by mass or more and 5.0 parts by mass or less, The dispersant contains at least one selected from the group consisting of polyester, polyether, phosphate ester, phosphate polyester, alkylamine salt, and alkylammonium salt compound. The resin composition for an antenna module according to claim 3.

7. Further containing a coupling agent, The amount of the coupling agent with respect to 100 parts by mass of the magnetic iron oxide filler is 0.1% by mass or more and 5.0 parts by mass or less, The coupling agent contains at least one selected from the group consisting of a silane coupling material, a titanate coupling material, a zirconate coupling agent, and an aluminate coupling agent. The resin composition for an antenna module according to claim 3.

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