WO2022137619A1

WO2022137619A1 - Antenna substrate

Info

Publication number: WO2022137619A1
Application number: PCT/JP2021/027510
Authority: WO
Inventors: 道和冨田
Original assignee: 株式会社フジクラ
Priority date: 2020-12-21
Filing date: 2021-07-26
Publication date: 2022-06-30
Also published as: JP2024016307A

Abstract

This antenna substrate comprises: an antenna; a power supply pattern; a core layer; a connection layer; an upper build-up part; and a lower build-up part. The power supply pattern is electrically connected to the antenna. The core layer includes a first reinforcement material and a first base material, and has a first surface and a second surface on the opposite side to the first surface. The connection layer includes a second reinforcement material and a second base material, and is disposed to face the first surface. The upper build-up part has at least one first non-reinforced layer which does not contain a reinforcement material, and is disposed between the core layer and a reinforcement layer. The lower build-up part has at least one second non-reinforced layer which does not contain a reinforcement material, and is disposed so as to face the second surface.

Description

Antenna board

The present invention relates to an antenna substrate.
This application claims priority based on Japanese Patent Application No. 2020-21930 filed in Japan on December 21, 2020, the contents of which are incorporated herein by reference.

Patent Document 1 discloses an antenna substrate having a plurality of layers including a core layer and a build-up layer laminated on the core layer. In such an antenna substrate, a glass cloth may be included in a part of the layers for reinforcement.

Japanese Patent Application Laid-Open No. 2020-136485

In an antenna board that handles high frequency signals such as millimeter wave bands, if the build-up layer contains glass cloth, the non-uniformity of the density of the glass cloth causes variations in transmission characteristics. Therefore, the configuration in which the build-up layer does not contain the glass cloth is more advantageous than the configuration in which the build-up layer contains the glass cloth in terms of transmission characteristics. However, when the build-up layer does not contain the glass cloth, there is a problem that the strength of the antenna substrate is lowered.

The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide an antenna substrate capable of both improving transmission characteristics and ensuring strength.

In order to solve the above problems, the antenna substrate according to one aspect of the present invention includes an antenna, a feeding pattern electrically connected to the antenna, a first reinforcing material, and a first base material, and has a first surface. A core layer having a second surface opposite to the first surface, a reinforcing layer containing a second reinforcing material and a second base material, and arranged so as to face the first surface of the core layer, and the above. An upper build-up portion having at least one non-reinforcing layer arranged between the core layer and the reinforcing layer and having at least one non-reinforcing material, and at least arranged facing the second surface and containing no reinforcing material. It comprises a lower build-up portion having one second non-reinforcing layer.

According to the above aspect, the first non-reinforced layer is included in the upper build-up portion. By arranging the antenna on the surface of the first non-reinforced layer, better transmission characteristics can be obtained as compared with the case where the antenna is arranged on the surface of the layer containing a reinforcing material such as glass cloth. Further, by providing the reinforcing layer containing the second reinforcing material in addition to the core layer containing the first reinforcing material, the strength of the antenna substrate can be ensured. From the above, it is possible to provide an antenna substrate that achieves both improvement in transmission characteristics and assurance of strength.

Here, the upper build-up portion and the reinforcing layer may be adhesively fixed by an adhesive layer.

Further, the thickness of the reinforcing layer may be larger than the thickness of the core layer.

Further, the material of the first reinforcing material and the material of the second reinforcing material may be the same, and the material of the first base material and the material of the second base material may be the same.

Further, at least one of the upper build-up portion and the lower build-up portion may further have a reinforcing layer containing a reinforcing material.

Further, at least one of the first non-reinforced layer and the second non-reinforced layer may be formed with filled vias whose inside is filled by plating.

Further, at least one of the upper build-up portion and the lower build-up portion is provided with two non-reinforcing layers adjacent to each other, and at least a part of the feeding pattern is adjacent to the two. It may be located between one non-reinforcing layer and may be in contact with each of the two adjacent non-reinforcing layers.

Further, the distance between the reinforcing layer and the core layer may be larger than the distance between the antenna and the core layer.

According to the above aspect of the present invention, it is possible to provide an antenna substrate capable of both improving transmission characteristics and ensuring strength.

It is sectional drawing of the antenna board which concerns on this embodiment.

Hereinafter, the antenna substrate of this embodiment will be described with reference to the drawings.
As shown in FIG. 1, the antenna substrate 1 includes a core layer 10, an upper build-up portion 20, a lower build-up portion 30, an adhesive layer 40, and a reinforcing layer 50. The core layer 10 has a first surface 11 and a second surface 12 opposite to the first surface 11.
The reinforcing layer 50 is arranged so as to face the first surface 11. The wording "arranged facing each other" described in the present specification means that the two members are arranged facing each other. That is, the wording "arranged facing each other" includes the case where an inclusion is present between the two members and the case where the inclusion is not present between the two members.

(Direction definition)
In the present specification, the direction in which each layer is laminated is referred to as a "stacking direction". The stacking direction is represented by the Z axis. The direction from the core layer 10 to the reinforcing layer 50 along the stacking direction is referred to as an upward direction or a + Z direction. The direction opposite to the + Z direction is referred to as the downward direction or the -Z direction. The first surface 11 is the upper surface of the core layer 10, and the second surface 12 is the lower surface of the core layer 10. FIG. 1 is a cross-sectional view of the antenna substrate 1 along the stacking direction. Viewing from the stacking direction is called "planar view". The stacking direction does not always match the vertical direction.
The lower build-up portion 30, the core layer 10, the upper build-up portion 20, the adhesive layer 40, and the reinforcing layer 50 are laminated in this order from the lower end to the upper end of the antenna substrate 1.

(antenna)
The antenna board 1 includes an antenna A, a feeding path 60, and a pad P. The antenna A is a pattern formed by conductors (for example, a patch antenna), and is configured to transmit and receive high-frequency radio signals (for example, 60 GHz band). The antenna A is arranged on the upper side (reinforcing layer 50 side) of the core layer 10. The position of the antenna A can be changed as appropriate. The antenna A may be formed between the upper build-up portion 20 and the adhesive layer 40, for example, as shown in FIG. The pad P is formed on the surface of the antenna substrate 1. In the example of FIG. 1, the pad P is formed on the lower surface of the lower build-up portion 30 (the lower surface of the third lower build-up layer 33). Terminals and the like of electronic components are soldered to the pad P. A solder resist (not shown) may be provided around the pad P. The feeding path 60 electrically connects the antenna A and the pad P.

The feeding path 60 shown in FIG. 1 includes

feeding vias

61, 62, 64, 65, 66, 68, 69 and

feeding patterns

63, 67. The power supply pattern 63 is also referred to as a first power supply pattern. The power supply pattern 67 is also referred to as a second power supply pattern 67. The feeding via 61 extends downward from the antenna A and is connected to the feeding via 62. The feeding pattern 63 is formed on the upper surface of the first upper build-up layer 21, which will be described later, and connects the feeding via 62 and the feeding via 64. The feeding via 65 is formed in the core layer 10, and connects the feeding via 64 and the feeding via 66. The feeding pattern 67 is formed on the lower surface of the first lower build-up layer 31, which will be described later, and connects the feeding via 66 and the feeding via 68. The feeding via 69 connects the feeding via 68 and the pad P. However, if the antenna A and the pad P can be electrically connected, the configuration of the feeding path 60 can be appropriately changed. In the following description, "feeding via 61, 62, 64, 65, 66, 68, 69" may be simply referred to as "feeding via 61 or the like".

The characteristic impedance of the

feed patterns

63 and 67 is matched to, for example, 50Ω. It is desirable that the

feeding patterns

63 and 67 are arranged on the surface of the layer that does not contain the glass cloth from the viewpoint of improving the transmission characteristics. Further, from the viewpoint of impedance matching, it is desirable that the thickness of the

feeding patterns

63 and 67 is about 100 μm. As shown in FIG. 1, the grounding pattern G is arranged in the region between the two layers adjacent to each other among the plurality of layers constituting the antenna substrate 1. However, the grounding pattern G may not be arranged in all the regions between the two layers. A plurality of grounding patterns G may be arranged so as to sandwich the

feeding patterns

63 and 67 in the stacking direction. Further, a plurality of ground vias (not shown) electrically connected to the ground pattern G may be arranged so as to surround the power feeding via 61 and the like. Similarly, a plurality of ground vias (not shown) may be arranged so as to surround the

feeding patterns

63 and 67 in a plan view.

(Base material and reinforcing material)
Each of the core layer 10 and the reinforcing layer 50 contains a base material and a reinforcing material. In the present specification, the base material contained in the core layer 10 may be particularly referred to as a "first base material", and the base material contained in the reinforcing layer 50 may be particularly referred to as a "second base material". Further, the reinforcing material contained in the core layer 10 may be particularly referred to as a "first reinforcing material", and the reinforcing material contained in the reinforcing layer 50 may be particularly referred to as a "second reinforcing material". Hereinafter, the case where the glass cloth is used as the reinforcing material (the first reinforcing material and the second reinforcing material) will be described, but a reinforcing material other than the glass cloth may be adopted. Further, the material of the first reinforcing material and the material of the second reinforcing material do not have to be the same as each other. The ordinal numbers such as "first" and "second" in the present specification are attached to avoid confusion of the constituent elements, and the quantity is not limited.

Epoxy or PPE can be used as the first base material of the core layer 10 and the second base material of the reinforcing layer 50. That is, the core layer 10 and the reinforcing layer 50 are layers formed by impregnating a reinforcing material (glass cloth or the like) with a base material (epoxy, PPE or the like). The core layer 10 and the reinforcing layer 50 may be a so-called prepreg material (Pre-Impregnated Material). The thickness of the core layer 10 and the reinforcing layer 50 is preferably 100 μm or more in consideration of the strength. From the viewpoint of high frequency design (matching of characteristic impedance, widening of the wide band of antenna A), it is desirable that the core layer 10 and the reinforcing layer 50 are thick to some extent. However, if the core layer 10 is too thick, problems may occur, so an appropriate value is selected.

(Core layer)
The core layer 10 contains a first base material and a first reinforcing material. The core layer 10 is provided with a feeding via 65. The feeding via 65 is formed by, for example, processing the core layer 10 with a drill or the like to form a through hole, and filling the inside of the through hole with metal. The diameter of the feeding via 65 (inner diameter of the through hole) is preferably 0.15 mm or less. As a result, it is possible to suppress a decrease in the strength of the core layer 10, which greatly contributes to the strength of the antenna substrate 1.

The coefficient of linear expansion of the core layer 10 in the direction orthogonal to the stacking direction (the direction in which the core layer 10 extends) is preferably 10 to 20 ppm / ° C., depending on the copper (Cu) that is the material of the wiring. As a result, the amount of expansion or contraction due to the temperature change becomes equal between the wiring and the core layer 10, and the thermal reliability can be improved.

(Upper build-up part and lower build-up part)
The upper build-up portion 20 is laminated on the upper surface of the core layer 10, and the lower build-up portion 30 is laminated on the lower surface of the core layer 10. The number of layers included in each build-up unit 20 and 30 can be appropriately changed, but is preferably two or more. Further, it is preferable that the number of layers included in the upper build-up unit 20 and the number of layers included in the lower build-up unit 30 are the same. For example, in FIG. 1, the upper build-up unit 20 and the lower build-up unit 30 each include three layers. As a result, the structure of the antenna substrate 1 in the middle of manufacturing becomes symmetrical in the stacking direction with the core layer 10 as the center. Therefore, it is possible to prevent the antenna substrate 1 from being warped.

In FIG. 1, the three layers included in the upper build-up portion 20 are divided into the first upper build-up layer 21, the second upper build-up layer 22, and the third upper build-up layer 23 in order from the layer closest to the core layer 10. Is called. Similarly, the three layers included in the lower build-up unit 30 are, in order from the layer closest to the core layer 10, the first lower build-up layer 31, the second lower build-up layer 32, and the third lower build. It is referred to as an up layer 33. When the upper build-up portion 20 and the lower build-up portion 30 are formed by the build-up method, the first upper build-up layer 21 and the first lower build-up layer 31 are formed at the same time with the second upper build-up layer 22. The second lower build-up layer 32 is formed at the same time, and the third upper build-up layer 23 and the third lower build-up layer 33 are formed at the same time.

The upper build-up layers 21 to 23 and the lower build-up layers 31 to 33 are all non-reinforced layers that do not contain a reinforcing material (glass cloth or the like). The upper build-up layers 21 to 23 are arranged so as to face the first surface 11. The lower build-up layers 31 to 33 are arranged so as to face the second surface 12. The upper build-up layers 21 to 23 may be referred to as first non-reinforced layers 21 to 23. The lower build-up layers 31 to 33 may be referred to as second non-reinforced layers 31 to 33. For the non-reinforced layer, it is not easy to control the coefficient of linear expansion. Therefore, it is particularly preferable to select a material having a small coefficient of linear expansion (for example, 50 ppm / ° C. or less) as the material of the non-reinforced layer.
The upper build-up layers 21 to 23 and the lower build-up layers 31 to 33 may contain an inorganic filler or the like. Thereby, the linear expansion coefficients of the upper build-up layers 21 to 23 and the lower build-up layers 31 to 33 may be adjusted, and the linear expansion coefficients may be matched with other layers included in the antenna substrate 1. In this case, the difference between the layers of the expansion amount or the contraction amount when the temperature change occurs becomes small, and improvement in thermal reliability can be expected.

As the material for forming the upper build-up layers 21 to 23 and the lower build-up layers 31 to 33, for example, a material having the following characteristics at 60 GHz is suitable.
Relative permittivity: Approximately 2 to 4 Dielectric loss tangent: 0.01 or less As a material for forming the upper build-up layers 21 to 23 and the lower build-up layers 31 to 33, for example, a material having the following characteristics at 60 GHz is used. , More suitable.
Relative permittivity: Approximately 3 Dielectric loss tangent: 0.005 or less Specific examples of the materials forming the upper build-up layers 21 to 23 and the lower build-up layers 31 to 33 include resins such as epoxy and PPE.

The thickness of the upper build-up layers 21 to 23 included in the upper build-up portion 20 and the lower build-up layers 31 to 33 included in the lower build-up portion 30 may be 100 μm or more in consideration of strength. preferable. From the viewpoint of high frequency design (matching of characteristic impedance, widening of the wide band of antenna A), it is desirable that the upper build-up layers 21 to 23 and the lower build-up layers 31 to 33 have a certain thickness. However, if these layers are too thick, problems may occur, so select an appropriate value for the thickness.

Feeding

vias

64, 62, and 61 are formed on the upper build-up layers 21 to 23, respectively. Feeding

vias

66, 68, and 69 are formed in the lower build-up layers 31 to 33, respectively. These feeding vias are preferably LVH (Laser Via Hole). More specifically, it is preferable that these feeding vias have a structure in which through holes are formed in each layer so that the diameter is 0.15 mm or less by laser processing, and the inside of the through holes is filled by plating. In other words, the feeding vias formed in the build-up portions 20 and 30 are preferably filled vias whose insides are filled by plating. When the diameter of the through hole is 0.15 mm or less, it is possible to suppress a decrease in strength of the antenna substrate 1 due to the formation of a large feeding via in the upper build-up layers 21 to 23 or the lower build-up layers 31 to 33.

Further, the upper build-up layers 21 to 23 and the lower build-up layers 31 to 33 are non-reinforced layers that do not contain a reinforcing material such as glass cloth. In other words, the upper build-up layers 21 to 23 are the first non-reinforced layers 21 to 23, and the lower build-up layers 31 to 33 are the second non-reinforced layers 31 to 33. Therefore, it is possible to suppress the occurrence of constriction in the through hole due to the fact that a part of the glass cloth or the like remains without being scraped during laser processing. As a result, a good shape of the feeding via can be obtained even with a fine diameter. Further, by filling the inside of the through hole with plating, the strength of the antenna substrate 1 can be further increased. The thickness of the upper build-up layers 21 to 23 and the lower build-up layers 31 to 33 is preferably 150 μm or less so that air bubbles or the like do not occur when the inside of the through hole is filled with plating. The structure and forming method of the feeding via are an example. For example, the feeding via may have a structure in which the inner peripheral surface of the through hole is conformally plated, the through hole is filled with a resin, and a lid is formed by plating.

(Reinforcing layer)
The reinforcing layer 50 is located above the upper build-up portion 20. In FIG. 1, the reinforcing layer 50 is adhesively fixed to the upper build-up portion 20 by the adhesive layer 40. As the material of the adhesive layer 40, for example, a resin (epoxy, PPE, etc.) that does not contain a reinforcing material such as glass cloth can be adopted. Alternatively, the material of the adhesive layer 40 may be the same prepreg material as the core layer 10, or may be another adhesive.

For example, the third upper build-up layer 23 may be formed of a thermoplastic resin. In this case, the reinforcing layer 50 and the third upper build-up layer 23 can be thermocompression bonded in a state where the reinforcing layer 50 is laminated on the surface of the third upper build-up layer 23. That is, the reinforcing layer 50 can be adhesively fixed to the upper build-up portion 20 without the adhesive layer 40. Therefore, the adhesive layer 40 is not essential.

The thickness of the reinforcing layer 50 is preferably larger than the thickness of the core layer 10. The thickness (dimension in the stacking direction) of the core layer 10 is set to a certain value or less from the viewpoint of ensuring the characteristics as a high frequency substrate. On the other hand, the limitation on the thickness of the reinforcing layer 50 is looser than the limitation on the thickness of the core layer 10. Therefore, the thickness of the reinforcing layer 50 can be easily made larger than the thickness of the core layer 10. Considering the difference in expansion coefficient, it is desirable that the material of the reinforcing layer 50 is the same as the material of the core layer 10. That is, the material of the second reinforcing material contained in the reinforcing layer 50 is preferably the same as the material of the first reinforcing material contained in the core layer 10. Similarly, the material of the second base material contained in the reinforcing layer 50 is preferably the same as the material of the first base material contained in the core layer 10.

(Production method)
Next, an example of the manufacturing method of the antenna substrate 1 configured as described above will be described. However, the antenna substrate 1 may be manufactured by another manufacturing method.
First, a prepreg material to be the core layer 10 is prepared. Next, the feeding via 65 is formed. Specifically, for example, a fine drill having a diameter of 0.1 mm or the like is used to form a through hole in the core layer 10, and the inside of the through hole is filled with metal. Further, a ground contact pattern G is formed on the upper surface and the lower surface of the core layer 10.

Next, the build-up materials are sequentially attached to both sides (upper surface and lower surface) of the core layer 10 in the stacking direction to form a symmetrical structure in the stacking direction. From the viewpoint of preventing warpage, it is more preferable that the thickness of each build-up material is the same as each other. If necessary, a wiring pattern is formed on the surface of the build-up material, and vias are formed on the build-up material.
In the example of FIG. 1, the first upper build-up layer 21 and the first lower build-up layer 31 are attached to both sides of the core layer 10 at the same time. Further, the feeding

vias

64 and 66 are formed by laser processing and plating fill. Further, the

power supply patterns

63 and 67 are formed on the upper surface of the first upper build-up layer 21 and the lower surface of the first lower build-up layer 31, respectively.

Next, the second upper build-up layer 22 and the second lower build-up layer 32 are simultaneously attached to the upper surface of the first upper build-up layer 21 and the lower surface of the first lower build-up layer 31, respectively. Similarly, via processing to the build-up layers 22 and 32, formation of the grounding pattern G, attachment of the build-up

layers

23 and 33, and the like are sequentially performed.

Next, the reinforcing layer 50 is attached to the upper build-up portion 20 by the adhesive layer 40. Finally, the antenna substrate 1 is cut into a predetermined size by processing a router or the like. At this time, the occurrence of cracks is suppressed by providing the reinforcing layer 50 including the reinforcing material.

As described above, the antenna substrate 1 of the present embodiment includes the antenna A, the feeding

patterns

63 and 67 electrically connected to the antenna A, the first reinforcing material, and the first base material, and has a first surface. A core layer 10 having a second surface 12 opposite to the first surface 11 and a reinforcing layer 50 containing a second reinforcing material and a second base material and arranged facing the first surface 11 and a core. Reinforcement arranged between the layer 10 and the reinforcement layer 50 and having an upper build-up portion 20 having at least one first non-reinforcing layer 21-23 without reinforcement and an arrangement facing the second surface 12. It comprises a lower build-up portion 30 having at least one second non-reinforced layer 31-33 containing no material. According to this configuration, since the first non-reinforced layer 23 is included in the upper build-up portion 20, by arranging the antenna A on the surface of the first non-reinforced layer 23, a reinforcing material such as glass cloth can be provided. Good transmission characteristics can be obtained as compared with the case where the antenna A is arranged on the surface of the including layer. Further, by providing the reinforcing layer 50 including the second reinforcing material in addition to the core layer 10 containing the first reinforcing material, the strength of the antenna substrate 1 can be ensured. From the above, it is possible to provide an antenna substrate 1 that achieves both improvement in transmission characteristics and assurance of strength.

Further, the upper build-up portion 20 and the reinforcing layer 50 are adhesively fixed by the adhesive layer 40. According to this configuration, the reinforcing layer 50 can be adhesively fixed after the outermost layer (third upper build-up layer 23 in FIG. 1) of the upper build-up portion 20 is thermocompression bonded.

Further, since the thickness of the reinforcing layer 50 is larger than the thickness of the core layer 10, the strength of the antenna substrate 1 can be increased more reliably. Since the transmission characteristic limitation on the thickness of the reinforcing layer 50 is looser than the transmission characteristic limitation on the thickness of the core layer 10, it is easy to increase the thickness of the reinforcing layer 50.

Further, the material of the first reinforcing material contained in the core layer 10 and the material of the second reinforcing material contained in the reinforcing layer 50 are the same, and the material of the first base material and the reinforcing layer 50 included in the core layer 10 are the same. The material of the second base material contained may be the same. In this case, the linear expansion coefficients of the core layer 10 and the reinforcing layer 50 are substantially the same, and it is possible to prevent the antenna substrate 1 from being warped due to a temperature change. In addition, "substantially the same" includes the case where it can be regarded as the same if the manufacturing error is removed.

Further, the first non-reinforced layers 21 to 23 (upper build-up layers 21 to 23) of the upper build-up portion 20 and the second non-reinforced layers 31 to 33 (lower build-up layers 31 to 33) of the lower build-up portion 30. ) And at least one layer may be formed with a filled via (feeding via 61 or the like) whose inside is filled by plating. According to this configuration, the strength of the antenna substrate 1 can be further increased.

Further, at least one of the upper build-up portion 20 and the lower build-up portion 30 has two non-reinforced layers (for example, the upper build-up layer (first non-reinforced layer) 21, 22), or the lower one, which does not contain a reinforcing material. Side build-up layers (second non-reinforced layers) 31, 32.) May be provided adjacent to each other. Further, at least a part of the

feeding patterns

63 and 67 may be located between the two adjacent non-reinforced layers and may be in contact with each of the two adjacent non-reinforced layers. According to this configuration, it is possible to prevent the

feeding patterns

63 and 67 from being affected by the non-uniformity of the density of the glass cloth and adversely affecting the transmission characteristics of the high frequency signal.

Further, in the antenna substrate 1 of the present embodiment, the reinforcing layer 50 is arranged at a position farther from the core layer 10 than the antenna A. In other words, the distance between the reinforcing layer 50 and the core layer 10 is larger than the distance between the antenna A and the core layer 10. According to this configuration, the antenna A is located between the two layers (core layer 10 and reinforcing layer 50) containing the reinforcing material. The portion between the two layers including the reinforcing material is not easily affected by bending deformation and the like. Therefore, it is possible to suppress bending deformation and the like from acting on the antenna A, and to stabilize the transmission / reception characteristics of the antenna A.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the above embodiment, the upper build-up layers 21 to 23 and the lower build-up layers 31 to 33 are the first non-reinforced layers 21 to 23 and the second non-reinforced layers 31 to 33 containing no reinforcing material. explained. However, some layers of the upper build-up portion 20 or some layers of the lower build-up portion 30 may contain a reinforcing material (glass cloth or the like). In other words, at least one of the upper build-up portion 20 and the lower build-up portion 30 may have a reinforcing layer having a reinforcing material. Also in this case, at least one layer included in the upper build-up section 20 and at least one layer included in the lower build-up section 30 are designated as non-reinforced layers.

The positions of the reinforced layer and the non-reinforced layer in the upper build-up portion 20 and the lower build-up portion 30 are preferably symmetrical in the stacking direction with the core layer 10 as the center. For example, when the upper build-up layer 23 is a reinforced layer and the upper build-up

layers

21 and 22 are non-reinforced layers (first non-reinforced layer), the lower build-up layer 33 is a reinforced layer and the lower build-up layer 31. , 32 is preferably a non-reinforced layer (second non-reinforced layer). As a result, the structure of the antenna substrate 1 in the middle of manufacturing can be made vertically symmetrical with the core layer 10 as the center, and the occurrence of warpage and the like can be suppressed.

As described above, when the reinforcing material is contained in a part of the upper build-up portion 20 or the lower build-up portion 30, the strength of the antenna substrate 1 can be further improved. Further, if the antenna A is arranged on the surface of the non-reinforced layer of the upper build-up portion 20 and the lower build-up portion 30, it is possible to improve the transmission characteristics and secure the strength at the same time.

Further, in the above embodiment, each of the upper build-up unit 20 and the lower build-up unit 30 has two adjacent non-reinforced layers. However, only one of the upper build-up section 20 and the lower build-up section 30 may have two adjacent non-reinforced layers. Even in this case, it is possible to reduce the adverse effect on the transmission characteristics of the high frequency signal.

In addition, it is possible to replace the constituent elements in the above-described embodiment with well-known constituent elements as appropriate without departing from the spirit of the present invention, and the above-described embodiments and modifications may be appropriately combined.

1 ... Antenna board 10 ... Core layer 11 ... 1st surface 12 ... 2nd surface 20 ... Upper build-up part 21-23 ... Upper build-up layer (1st non-reinforced layer) 30 ... Lower build-up part 31-33 ... Lower build-up layer (second non-reinforced layer) 40 ... Adhesive layer 50 ... Reinforcing

layer

61, 62, 64, 65, 66, 68, 69 ... Feeding via (filled via) 63, 67 ... Feeding pattern A ... Antenna Z ... Stacking direction

Claims

With the antenna
The feeding pattern electrically connected to the antenna and
A core layer containing a first reinforcing material and a first substrate and having a first surface and a second surface opposite to the first surface.
A reinforcing layer containing a second reinforcing material and a second base material and arranged facing the first surface,
An upper build-up portion located between the core layer and the reinforcing layer and having at least one first non-reinforcing layer that does not contain a reinforcing material.
An antenna substrate comprising a lower build-up portion that is disposed facing the second surface and has at least one second non-reinforcing layer that does not contain a reinforcing material.
The antenna substrate according to claim 1, wherein the upper build-up portion and the reinforcing layer are adhesively fixed by an adhesive layer.
The antenna substrate according to claim 1 or 2, wherein the thickness of the reinforcing layer is larger than the thickness of the core layer.
The material of the first reinforcing material and the material of the second reinforcing material are the same,
The antenna substrate according to any one of claims 1 to 3, wherein the material of the first base material and the material of the second base material are the same.
The antenna substrate according to any one of claims 1 to 4, wherein at least one of the upper build-up portion and the lower build-up portion further has a reinforcing layer containing a reinforcing material.
The antenna substrate according to any one of claims 1 to 5, wherein a filled via whose inside is filled by plating is formed on at least one of the first non-reinforced layer and the second non-reinforced layer.
Two non-reinforcing layers containing no reinforcing material are provided adjacent to each other on at least one of the upper build-up portion and the lower build-up portion.
13. Antenna board.
The antenna substrate according to any one of claims 1 to 7, wherein the distance between the reinforcing layer and the core layer is larger than the distance between the antenna and the core layer.