Multilayer substrate

Abstract

A laminate according to the present invention has a structure in which a plurality of liquid crystal polymer layers including a first liquid crystal polymer layer, a second liquid crystal polymer layer, and a third liquid crystal polymer layer are laminated in the Z-axis direction. Among the plurality of liquid crystal polymer layers, the first liquid crystal polymer layer is positioned furthest in the positive direction along the Z axis. Among the plurality of liquid crystal polymer layers, the third liquid crystal polymer layer is positioned furthest in the negative direction along the Z axis. One or more first conductor layers are positioned between the first liquid crystal polymer layer and the second liquid crystal polymer layer and / or between the second liquid crystal polymer layer and the third liquid crystal polymer layer. The gas permeability per unit volume of the first liquid crystal polymer layer and the gas permeability per unit volume of the third liquid crystal polymer layer are greater than the gas permeability per unit volume of the second liquid crystal polymer layer.

Description

[Technical Field]

[0001] The present invention relates to a multilayer substrate having a structure in which a plurality of liquid crystal polymer layers are stacked. [Background technology]

[0002] A known example of a conventional invention relating to a multilayer board is the resin multilayer board described in Patent Document 1. This resin multilayer board includes a plurality of insulating resin substrate layers and a plurality of conductor patterns. The plurality of insulating resin substrate layers are stacked in a vertical direction. A plurality of conductor patterns are provided within the resin multilayer board. The plurality of conductor patterns are provided with gas vent holes. This allows gas generated inside the resin multilayer board during manufacturing to be released to the outside of the resin multilayer board through the holes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 098012 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, in the field of the resin multilayer substrate described in Patent Document 1, there is a demand for releasing gas generated inside the resin multilayer substrate to the outside of the multilayer substrate, while also preventing moisture-laden air from entering the interior of the resin multilayer substrate.

[0005] Therefore, an object of the present invention is to provide a multilayer substrate that can release gas generated inside the multilayer substrate to the outside of the multilayer substrate and can prevent moisture-containing air from entering the inside of the multilayer substrate. [Means for solving the problem]

[0006] A multilayer substrate according to one embodiment of the present invention comprises: a laminate having a structure in which a plurality of liquid crystal polymer layers including a first liquid crystal polymer layer, a second liquid crystal polymer layer, and a third liquid crystal polymer layer are stacked in the Z-axis direction, wherein the first liquid crystal polymer layer is located furthest in the positive direction of the Z-axis among the plurality of liquid crystal polymer layers, the third liquid crystal polymer layer is located furthest in the negative direction of the Z-axis among the plurality of liquid crystal polymer layers, and the second liquid crystal polymer layer is located between the first liquid crystal polymer layer and the third liquid crystal polymer layer in the Z-axis direction; one or more conductor layers provided on the laminate; It is equipped with the one or more conductor layers include one or more first conductor layers located between the first liquid crystal polymer layer and the second liquid crystal polymer layer and / or between the second liquid crystal polymer layer and the third liquid crystal polymer layer; The gas permeation amount per unit volume of the first liquid crystal polymer layer and the gas permeation amount per unit volume of the third liquid crystal polymer layer are greater than the gas permeation amount per unit volume of the second liquid crystal polymer layer.

[0007] A multilayer substrate according to one embodiment of the present invention comprises: a laminate having a structure in which a plurality of liquid crystal polymer layers including a first liquid crystal polymer layer, a second liquid crystal polymer layer, and a third liquid crystal polymer layer are stacked in the Z-axis direction, wherein the first liquid crystal polymer layer is located furthest in the positive direction of the Z-axis among the plurality of liquid crystal polymer layers, the third liquid crystal polymer layer is located furthest in the negative direction of the Z-axis among the plurality of liquid crystal polymer layers, and the second liquid crystal polymer layer is located between the first liquid crystal polymer layer and the third liquid crystal polymer layer in the Z-axis direction; one or more conductor layers provided on the laminate; It is equipped with the one or more conductor layers include one or more first conductor layers located between the first liquid crystal polymer layer and the second liquid crystal polymer layer and / or between the second liquid crystal polymer layer and the third liquid crystal polymer layer; The second liquid crystal polymer layer has a higher crystallinity than the first liquid crystal polymer layer and the third liquid crystal polymer layer. [Effects of the Invention]

[0008] According to the multilayer board of the present invention, gas generated inside the multilayer board can be released to the outside of the multilayer board, and moisture-laden air can be prevented from entering the inside of the multilayer board. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an exploded perspective view of a multilayer substrate 10. As shown in FIG. [Figure 2] FIG. 2 is a cross-sectional view of the multilayer substrate 10. [Figure 3] FIG. 3 is a front view of the multilayer substrate 10 when in use. [Figure 4] FIG. 4 is an exploded perspective view of the multilayer substrate 10a. [Figure 5] FIG. 5 is a top view of liquid crystal polymer layers 16a, 17, and 16c of multilayer substrate 10b. [Figure 6] FIG. 6 is a cross-sectional view of the multilayer substrate 10c. [Figure 7] FIG. 7 is a front view of the multilayer substrate 10c when in use. [Figure 8] FIG. 8 is a cross-sectional view of the multilayer substrate 10d. [Figure 9] FIG. 9 is a cross-sectional view of the multilayer substrate 10e. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Embodiment) [Multilayer board structure] The structure of a multilayer substrate 10 according to an embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is an exploded perspective view of the multilayer substrate 10. Fig. 2 is a cross-sectional view of the multilayer substrate 10. Fig. 2 shows a cross section perpendicular to the front-to-rear direction. Fig. 3 is a front view of the multilayer substrate 10 when in use. Note that in Fig. 1, reference symbols are assigned only to representative interlayer connection conductors v3 and v4 among the multiple interlayer connection conductors v3 and v4.

[0011] In this specification, directions are defined as follows: The stacking direction of the laminate 12 of the multilayer substrate 10 is defined as the up-down direction. The up-down direction also coincides with the Z-axis direction. The up-down direction is the positive direction of the Z-axis. The down-down direction is the negative direction of the Z-axis. The direction in which the signal conductor layers 20 of the multilayer substrate 10 extend is defined as the left-right direction. The line width direction of the signal conductor layers 20 when viewed in the up-down direction is defined as the front-rear direction. The up-down direction, front-rear direction, and left-rear direction are perpendicular to each other. Note that the up-down direction and the down-down direction in the up-down direction may be interchanged, the left-right direction and the right-left direction may be interchanged, and the front-rear direction in the front-rear direction may be interchanged.

[0012] Hereinafter, X is a component or member of the multilayer substrate 10. In this specification, unless otherwise specified, each part of X is defined as follows: The front part of X means the front half of X. The rear part of X means the rear half of X. The left part of X means the left half of X. The right part of X means the right half of X. The upper part of X means the upper half of X. The lower part of X means the lower half of X. The front end of X means the front end of X. The rear end of X means the rear end of X. The left end of X means the left end of X. The right end of X means the right end of X. The upper end of X means the upper end of X. The lower end of X means the lower end of X. The front end of X means the front end of X and its vicinity. The rear end of X means the rear end of X and its vicinity. The left end of X means the left end of X and its vicinity. The right end of X means the right end of X and its vicinity. The upper end of X means the upper end of X and its vicinity. The lower end of X means the lower end of X and its vicinity.

[0013] First, the structure of a multilayer substrate 10 will be described with reference to FIG. 1. The multilayer substrate 10 transmits high-frequency signals. The multilayer substrate 10 is used to electrically connect two circuits in electronic devices such as smartphones. As shown in FIG. 1, the multilayer substrate 10 includes a laminate 12, protective layers 18a and 18b, a signal conductor layer 20 (one or more conductor layers), a first ground conductor layer 22 (one or more conductor layers), a second ground conductor layer 24 (one or more conductor layers), signal terminals 26a and 26b (one or more conductor layers), connection conductor layers 28a and 28b (one or more conductor layers), interlayer connection conductors v1 and v2, and a plurality of interlayer connection conductors v3 and v4.

[0014] The laminate 12 has a plate shape. Therefore, the laminate 12 has an upper main surface and a lower main surface. The upper and lower main surfaces of the laminate 12 have a rectangular shape with long sides extending in the left-right direction. Therefore, the length of the laminate 12 in the left-right direction is longer than the length of the laminate 12 in the front-rear direction. The laminate 12 is flexible.

[0015] As shown in FIG. 1, the laminate 12 has a structure in which liquid crystal polymer layers 16a to 16c, 17, including a liquid crystal polymer layer 16a (first liquid crystal polymer layer), a liquid crystal polymer layer 17 (second liquid crystal polymer layer), and a liquid crystal polymer layer 16c (third liquid crystal polymer layer), are stacked in the Z-axis direction. The liquid crystal polymer layers 16a, 16b, 17, and 16c are arranged in this order from top to bottom. Therefore, the liquid crystal polymer layer 16a (first liquid crystal polymer layer) is located at the top (positive direction of the Z-axis) of the liquid crystal polymer layers 16a to 16c, 17. The liquid crystal polymer layer 16c (third liquid crystal polymer layer) is located at the bottom (negative direction of the Z-axis) of the liquid crystal polymer layers 16a to 16c, 17. The liquid crystal polymer layer 17 (second liquid crystal polymer layer) is located between the liquid crystal polymer layer 16a (first liquid crystal polymer layer) and the liquid crystal polymer layer 16c (third liquid crystal polymer layer) in the vertical direction (Z-axis direction). Each of the liquid crystal polymer layers 16a to 16c and the liquid crystal polymer layer 17 (second liquid crystal polymer layer) has an upper main surface (a positive main surface located in the positive direction of the Z-axis) and a lower main surface (a negative main surface located in the negative direction of the Z-axis).

[0016] No insulating layer made of a material different from the liquid crystal polymer is provided between the liquid crystal polymer layer 16a and the liquid crystal polymer layer 16b, between the liquid crystal polymer layer 16b and the liquid crystal polymer layer 17, or between the liquid crystal polymer layer 17 and the liquid crystal polymer layer 16c. Therefore, the liquid crystal polymer layer 16a contacts the liquid crystal polymer layer 16b. The liquid crystal polymer layer 16a is fused to the liquid crystal polymer layer 16b. The liquid crystal polymer layer 16b contacts the liquid crystal polymer layer 17. The liquid crystal polymer layer 16b is fused to the liquid crystal polymer layer 17. The liquid crystal polymer layer 17 contacts the liquid crystal polymer layer 16c. The liquid crystal polymer layer 17 is fused to the liquid crystal polymer layer 16c.

[0017] The gas permeation rates per unit volume of the liquid crystal polymer layer 16a (first liquid crystal polymer layer), the liquid crystal polymer layer 16b, and the liquid crystal polymer layer 16c (third liquid crystal polymer layer) are all greater than the gas permeation rate per unit volume of the liquid crystal polymer layer 17 (second liquid crystal polymer layer). The gas permeation rates refer to the oxygen permeation rate at 25°C (during use) and the carbon dioxide permeation rate at 200°C (when the laminate is pressure-bonded). The gas permeation rates are measured, for example, by the following procedure: First, a liquid crystal polymer layer having a predetermined thickness and area is prepared. Gas is sealed in the space facing the upper main surface of the liquid crystal polymer layer, and the space facing the lower main surface of the liquid crystal polymer layer is evacuated. Then, after a predetermined time has elapsed, the amount of gas present in the space facing the lower main surface of the liquid crystal polymer layer is measured. The gas is water vapor.

[0018] To achieve the above structure, the crystallinity of the liquid crystal polymer layer 17 (second liquid crystal polymer layer) is higher than the crystallinity of the liquid crystal polymer layer 16a (first liquid crystal polymer layer), the crystallinity of the liquid crystal polymer layer 16b, and the crystallinity of the liquid crystal polymer layer 16c (third liquid crystal polymer layer). The crystallinity of the liquid crystal polymer layer is measured by, for example, X-ray diffraction, DSC (differential scanning calorimetry), FT-IR, solid-state NMR, or the like. The DSC is, for example, a DSC3 manufactured by Mettler-Toledo. There is a correlation between the crystallinity and the gas permeability. Specifically, as the crystallinity increases, the gas permeability decreases.

[0019] The elastic modulus of the liquid crystal polymer layer 16a (first liquid crystal polymer layer), the elastic modulus of the liquid crystal polymer layer 16b, and the elastic modulus of the liquid crystal polymer layer 16c (third liquid crystal polymer layer) are lower than the elastic modulus of the liquid crystal polymer layer 17 (second liquid crystal polymer layer).

[0020] To achieve the above structure, the liquid crystal polymer layer 16a (first liquid crystal polymer layer), the liquid crystal polymer layer 16b, and the liquid crystal polymer layer 16c (third liquid crystal polymer layer) are made of, for example, a wholly aromatic polyester resin containing less than 50 mol% of 2-hydroxy-6-naphthoic acid units. The liquid crystal polymer layer 17 (second liquid crystal polymer layer) is made of, for example, a wholly aromatic polyester resin containing 50 mol% or more of 2-hydroxy-6-naphthoic acid units.

[0021] When the above materials are used, the dielectric tangent of the liquid crystal polymer layer 17 (second liquid crystal polymer layer) is smaller than the dielectric tangent of the liquid crystal polymer layer 16a (first liquid crystal polymer layer), the dielectric tangent of the liquid crystal polymer layer 16b, and the dielectric tangent of the liquid crystal polymer layer 16c (third liquid crystal polymer layer).

[0022] A high-frequency signal is transmitted through the signal conductor layer 20. The signal conductor layer 20 (first conductor layer) is located between the liquid crystal polymer layer 17 (second liquid crystal polymer layer) and the liquid crystal polymer layer 16c (third liquid crystal polymer layer). In this embodiment, the signal conductor layer 20 (first conductor layer, sixth conductor layer) is located on the lower main surface (negative main surface) of the liquid crystal polymer layer 17 (second liquid crystal polymer layer). As a result, the signal conductor layer 20 (first conductor layer, internal conductor layer) is in contact with the liquid crystal polymer layer 17 (second liquid crystal polymer layer). The signal conductor layer 20 has a linear shape extending in the left-right direction.

[0023] As shown in FIG. 1 , the first ground conductor layer 22 is provided on the laminate 12. The first ground conductor layer 22 is located above the signal conductor layer 20 (positive direction of the Z-axis) and overlaps with the signal conductor layer 20 when viewed in the up-down direction (Z-axis direction). In this embodiment, the first ground conductor layer 22 is located on the upper main surface of the liquid crystal polymer layer 16a. As a result, the first ground conductor layer 22 (third conductor layer) is in contact with the liquid crystal polymer layer 16a (first liquid crystal polymer layer). The first ground conductor layer 22 also covers substantially the entire upper main surface of the liquid crystal polymer layer 16a. Therefore, the area of ​​the first ground conductor layer 22 (third conductor layer) is larger than the area of ​​the signal conductor layer 20 (internal conductor layer). A ground potential is connected to the first ground conductor layer 22.

[0024] As shown in FIG. 1 , the second ground conductor layer 24 is provided in the laminate 12. The second ground conductor layer 24 is located below the signal conductor layer 20 (in the negative direction of the Z axis) and overlaps the signal conductor layer 20 when viewed in the up-down direction (the Z axis direction). In this embodiment, the second ground conductor layer 24 is located on the lower main surface of the liquid crystal polymer layer 16c. As a result, the second ground conductor layer 24 (fourth conductor layer) is in contact with the liquid crystal polymer layer 16c (third liquid crystal polymer layer). The second ground conductor layer 24 also covers substantially the entire lower main surface of the liquid crystal polymer layer 16c. Therefore, the area of ​​the second ground conductor layer 24 (fourth conductor layer) is larger than the area of ​​the signal conductor layer 20 (internal conductor layer). A ground potential is connected to the second ground conductor layer 24. The signal conductor layer 20, the first ground conductor layer 22, and the second ground conductor layer 24 as described above have a stripline structure.

[0025] The signal terminal 26a is provided at the left end of the laminate 12. More specifically, the signal terminal 26a is located on the upper main surface of the liquid crystal polymer layer 16a. When viewed in the vertical direction, the signal terminal 26a overlaps with the left end of the signal conductor layer 20. When viewed in the vertical direction, the signal terminal 26a has a rectangular shape. The signal terminal 26a is an external terminal through which high-frequency signals are input and output. The signal terminal 26a does not contact the first ground conductor layer 22.

[0026] The connecting conductor layer 28a is provided at the left end of the laminate 12. More specifically, the connecting conductor layer 28a (first conductor layer) is located between the liquid crystal polymer layer 16a (first liquid crystal polymer layer) and the liquid crystal polymer layer 17 (second liquid crystal polymer layer). In this embodiment, the connecting conductor layer 28a is located on the lower main surface of the liquid crystal polymer layer 16b. In other words, the connecting conductor layer 28a (first conductor layer, fifth conductor layer) is located on the upper main surface (front main surface) of the liquid crystal polymer layer 17 (second liquid crystal polymer layer). The connecting conductor layer 28a overlaps with the left end of the signal conductor layer 20 when viewed in the vertical direction. The connecting conductor layer 28a has a rectangular shape when viewed in the vertical direction.

[0027] The interlayer connection conductor v1 electrically connects the signal terminal 26a, the connection conductor layer 28a, and the left end of the signal conductor layer 20. More specifically, as shown in FIG. 2, the interlayer connection conductor v1 includes interlayer connection conductors v1a, v1b, and v1c. The interlayer connection conductor v1a penetrates the liquid crystal polymer layer 16a in the vertical direction. The interlayer connection conductor v1a is in contact with the signal terminal 26a. However, the interlayer connection conductor v1a does not penetrate the signal terminal 26a in the vertical direction. The interlayer connection conductor v1b penetrates the liquid crystal polymer layer 16b in the vertical direction. The interlayer connection conductor v1b is in contact with the interlayer connection conductor v1a and the connection conductor layer 28a. However, the interlayer connection conductor v1b does not penetrate the connection conductor layer 28a in the vertical direction. The interlayer connection conductor v1c penetrates the liquid crystal polymer layer 17 (second liquid crystal polymer layer) in the vertical direction. The interlayer connection conductor v1c is in contact with the connection conductor layer 28a (fifth conductor layer) and the signal conductor layer 20 (sixth conductor layer). However, the interlayer connection conductor v1c does not penetrate the connection conductor layer 28a (fifth conductor layer) and the signal conductor layer 20 (sixth conductor layer) in the up-down direction (Z-axis direction). The structures of the signal terminal 26b, the connection conductor layer 28b, and the interlayer connection conductor v2 are symmetrical to the structures of the signal terminal 26a, the connection conductor layer 28a, and the interlayer connection conductor v1, and therefore will not be described.

[0028] As shown in FIG. 1 , the multiple interlayer connection conductors v3 are located in front of the signal conductor layer 20. The multiple interlayer connection conductors v3 are aligned in a row in the left-right direction. The multiple interlayer connection conductors v3 penetrate the liquid crystal polymer layers 16a, 16b, 17, and 16c in the up-down direction. As a result, the multiple interlayer connection conductors v3 electrically connect the first ground conductor layer 22 and the second ground conductor layer 24.

[0029] The interlayer connection conductors v4 are located behind the signal conductor layer 20. The interlayer connection conductors v4 are aligned in a row in the left-right direction. The interlayer connection conductors v4 penetrate the liquid crystal polymer layers 16a, 16b, 17, and 16c in the up-down direction. As a result, the interlayer connection conductors v4 electrically connect the first ground conductor layer 22 and the second ground conductor layer 24.

[0030] The first ground conductor layer 22, the second ground conductor layer 24, the signal terminals 26a, 26b, and the connecting conductor layers 28a, 28b are formed, for example, by etching a metal foil provided on the upper or lower main surface of the liquid crystal polymer layers 16a to 16c, 17. The metal foil is, for example, a copper foil.

[0031] The interlayer connection conductors v1 to v4 are, for example, via-hole conductors. The via-hole conductors are fabricated by forming through-holes in the liquid crystal polymer layers 16a to 16c, 17, filling the through-holes with conductive paste, and sintering the conductive paste. The material of the interlayer connection conductors v1 to v4 is a mixture of resin and metal. However, the material of the interlayer connection conductors v1 to v4 may contain metal but not resin.

[0032] The protective layer 18a (first protective layer) covers the upper main surface (the main surface in the positive direction of the Z axis) of the laminate 12. As a result, the protective layer 18a protects the first ground conductor layer 22. However, openings h1 to h6 are provided in the protective layer 18a. The opening h1 overlaps with the signal terminal 26a when viewed in the top-bottom direction. As a result, the signal terminal 26a is exposed to the outside from the multilayer substrate 10. The opening h2 is located in front of the opening h1. A portion of the first ground conductor layer 22 is exposed to the outside from the multilayer substrate 10 through the opening h2. The opening h3 is located behind the opening h1. A portion of the first ground conductor layer 22 is exposed to the outside from the multilayer substrate 10 through the opening h3. As a result, the portion of the first ground conductor layer 22 functions as a ground terminal. Note that the structure of the openings h4 to h6 is symmetrical to the structure of the openings h1 to h3, and therefore a description thereof will be omitted.

[0033] The protective layer 18b (second protective layer) covers the lower main surface (main surface in the negative direction of the Z axis) of the laminate 12. In this way, the protective layer 18b protects the second ground conductor layer 24.

[0034] The protective layers 18a and 18b described above do not contain a liquid crystal polymer. Therefore, the protective layers 18a and 18b are not part of the laminate 12. The protective layers 18a and 18b are, for example, resist layers. The gas permeation rate per unit volume of the protective layer 18a (first protective layer) and the gas permeation rate per unit volume of the protective layer 18b (second protective layer) are greater than the gas permeation rate per unit volume of the liquid crystal polymer layer 16a (first liquid crystal polymer layer) and the gas permeation rate per unit volume of the liquid crystal polymer layer 16c (third liquid crystal polymer layer). Such protective layers 18a and 18b are formed after the thermocompression bonding process of the laminate 12.

[0035] The multilayer substrate 10 described above is flexible. Therefore, as shown in FIG. 3, the multilayer substrate 10 can be bent. Specifically, the multilayer substrate 10 has a first section A1, a second section A2, and a third section A3. When the multilayer substrate 10 is not bent, the first section A1, the second section A2, and the third section A3 are arranged in this order from left to right. The second section A2 is bent downward relative to the first section A1. Meanwhile, the first section A1 and the third section A3 are not bent. However, the first section A1 and the third section A3 may be slightly bent. In this case, the radius of curvature of the first section A1 and the radius of curvature of the third section A3 are larger than the radius of curvature of the second section A2.

[0036] [effect] According to the multilayer substrate 10, gas generated inside the multilayer substrate 10 can be released to the outside of the multilayer substrate 10, and moisture-laden air can be prevented from entering the inside of the multilayer substrate 10. More specifically, in the multilayer substrate 10, the gas permeation rate per unit volume of the liquid crystal polymer layer 16a (first liquid crystal polymer layer) and the gas permeation rate per unit volume of the liquid crystal polymer layer 16c (third liquid crystal polymer layer) are greater than the gas permeation rate per unit volume of the liquid crystal polymer layer 17 (second liquid crystal polymer layer). As a result, gas generated inside the multilayer substrate 10 during manufacturing is released to the outside of the multilayer substrate 10 via the liquid crystal polymer layers 16a and 16c. On the other hand, when the multilayer substrate 10 is in use, moisture-laden air is less likely to enter the inside of the multilayer substrate 10 due to the presence of the liquid crystal polymer layer 17. As a result, moisture present in the liquid crystal polymer layer 17 is reduced.

[0037] Here, the lower principal surfaces of the connecting conductor layers 28a and 28b (first conductor layers) located between the liquid crystal polymer layer 16a (first liquid crystal polymer layer) and the liquid crystal polymer layer 17 (second liquid crystal polymer layer) are located near the liquid crystal polymer layer 17. In this embodiment, the lower principal surfaces of the connecting conductor layers 28a and 28b (first conductor layers) are in contact with the liquid crystal polymer layer 17. Therefore, when the moisture present in the liquid crystal polymer layer 17 is reduced, corrosion due to moisture in the vicinity of the lower principal surfaces of the connecting conductor layers 28a and 28b (first conductor layers) is suppressed. Similarly, the upper principal surface of the signal conductor layer 20 (first conductor layer) located between the liquid crystal polymer layer 17 (second liquid crystal polymer layer) and the liquid crystal polymer layer 16c (third liquid crystal polymer layer) is located near the liquid crystal polymer layer 17. In this embodiment, the upper principal surface of the signal conductor layer 20 (first conductor layer) is in contact with the liquid crystal polymer layer 17. Therefore, when the amount of moisture present in the liquid crystal polymer layer 17 is reduced, the vicinity of the upper main surface of the signal conductor layer 20 is prevented from being corroded by moisture.

[0038] 3, when the multilayer substrate 10 is bent, a large tensile stress is applied to the liquid crystal polymer layer 16a and a large compressive stress is applied to the liquid crystal polymer layer 16c, and the compressive stress and tensile stress are not easily applied to the liquid crystal polymer layer 17. Therefore, the crystallinity of the liquid crystal polymer layer 16a (first liquid crystal polymer layer) and the crystallinity of the liquid crystal polymer layer 16c (third liquid crystal polymer layer) are lower than the crystallinity of the liquid crystal polymer layer 17 (second liquid crystal polymer layer). As a result, the elastic modulus of the liquid crystal polymer layer 16a and the liquid crystal polymer layer 16c are lower than the elastic modulus of the liquid crystal polymer layer 17. Therefore, the liquid crystal polymer layers 16a and 16c are more easily deformed, and damage to the liquid crystal polymer layers 16a and 16c is suppressed.

[0039] Furthermore, the liquid crystal polymer layers 16a-16c, 17 are characterized by their susceptibility to plastic deformation when heated. However, the liquid crystal polymer layers 16a-16c, 17 are susceptible to gas generation when heated. Furthermore, when the multilayer substrate 10 is bent, it is preferable that the liquid crystal polymer layers 16a, 16c near the surface of the laminate 12 have a low modulus of elasticity. Therefore, in the multilayer substrate 10, the liquid crystal polymer layers 16a, 16c have a low degree of crystallinity. This allows gas generated in the laminate 12 to be released to the outside of the laminate, and makes the laminate 12 more susceptible to bending.

[0040] The materials for the liquid crystal polymer layer 16a (first liquid crystal polymer layer), the liquid crystal polymer layer 16b, and the liquid crystal polymer layer 16c (third liquid crystal polymer layer) are, for example, wholly aromatic polyester resins containing less than 50 mol% of 2-hydroxy-6-naphthoic acid units. The material for the liquid crystal polymer layer 17 (second liquid crystal polymer layer) is, for example, wholly aromatic polyester resins containing 50 mol% or more of 2-hydroxy-6-naphthoic acid units. As a result, the gas permeability per unit volume of the liquid crystal polymer layer 16a (first liquid crystal polymer layer) and the gas permeability per unit volume of the liquid crystal polymer layer 16c (third liquid crystal polymer layer) are greater than the gas permeability per unit volume of the liquid crystal polymer layer 17 (second liquid crystal polymer layer). As a result, the multilayer substrate 10 can release gas generated inside the multilayer substrate 10 to the outside and prevent moisture-laden air from entering the multilayer substrate 10.

[0041] The signal conductor layer 20 is in contact with the liquid crystal polymer layer 17 (second liquid crystal polymer layer). In the above-mentioned material, the dielectric loss tangent of the liquid crystal polymer layer 17 (second liquid crystal polymer layer) is smaller than the dielectric loss tangent of the liquid crystal polymer layer 16a (first liquid crystal polymer layer) and the dielectric loss tangent of the liquid crystal polymer layer 16c (third liquid crystal polymer layer). This reduces the dielectric loss occurring in the high-frequency signal transmitted through the signal conductor layer 20.

[0042] Furthermore, the multilayer substrate 10 can release gas generated inside the multilayer substrate 10 to the outside, and can prevent moisture-laden air from entering the multilayer substrate 10. More specifically, the laminate 12 is fabricated by stacking the liquid crystal polymer layers 16a-16c, 17 and then hot-pressing the liquid crystal polymer layers 16a-16c, 17. During this hot-pressing, gas is generated inside the laminate 12. Therefore, the signal conductor layer 20 (internal conductor layer) having a small area is in contact with the liquid crystal polymer layer 17 (second liquid crystal polymer layer) having a small gas permeability. The first ground conductor layer 22 (third conductor layer) having a large area is in contact with the liquid crystal polymer layer 16a (first liquid crystal polymer layer) having a large gas permeability. The second ground conductor layer 24 (fourth conductor layer) having a large area is in contact with the liquid crystal polymer layer 16c (third liquid crystal polymer layer) having a large gas permeability. As a result, the gas in the liquid crystal polymer layer 17 is easily released to the outside of the multilayer substrate 10 because the liquid crystal polymer layer 17 is not largely covered by the signal conductor layer 20. As a result, peeling of the signal conductor layer 20 and the connecting conductor layers 28a, 28b is suppressed in the multilayer substrate 10. Furthermore, since the liquid crystal polymer layers 16a, 16c are largely covered by the first ground conductor layer 22 and the second ground conductor layer 24, the intrusion of moisture-laden air into the interior of the multilayer substrate 10 is suppressed.

[0043] Furthermore, the gas permeation rate per unit volume of protective layer 18a (first protective layer) and the gas permeation rate per unit volume of protective layer 18b (second protective layer) are greater than the gas permeation rate per unit volume of liquid crystal polymer layer 16a (first liquid crystal polymer layer) and the gas permeation rate per unit volume of liquid crystal polymer layer 16c (third liquid crystal polymer layer). This allows gas generated inside multilayer substrate 10 to be further released to the outside of multilayer substrate 10, and further prevents moisture-laden air from entering the inside of multilayer substrate 10.

[0044] In the multilayer substrate 10, the material of the interlayer connection conductor v1c is a mixture of resin and metal. Such interlayer connection conductor v1c is hardened by heating during manufacturing. At this time, the interlayer connection conductor v1c generates gas. Furthermore, the interlayer connection conductor v1c does not penetrate the connection conductor layer 28a (fifth conductor layer) and the signal conductor layer 20 (sixth conductor layer) in the vertical direction (Z-axis direction). Therefore, gas is easily trapped between the connection conductor layer 28a (fifth conductor layer) and the signal conductor layer 20 (sixth conductor layer).

[0045] Therefore, in the multilayer substrate 10, the gas permeation rate per unit volume of the liquid crystal polymer layer 16a (first liquid crystal polymer layer) and the gas permeation rate per unit volume of the liquid crystal polymer layer 16c (third liquid crystal polymer layer) are greater than the gas permeation rate per unit volume of the liquid crystal polymer layer 17 (second liquid crystal polymer layer). As a result, gas generated inside the multilayer substrate 10 during manufacturing is released to the outside of the multilayer substrate 10 through the liquid crystal polymer layers 16a and 16c. On the other hand, when the multilayer substrate 10 is in use, the liquid crystal polymer layer 17 prevents moisture-laden air from penetrating into the interior of the multilayer substrate 10. As a result, the moisture present in the liquid crystal polymer layer 17 is reduced.

[0046] (First Modification) A multilayer substrate 10a according to a first modified example will be described below with reference to the drawings. Figure 4 is an exploded perspective view of the multilayer substrate 10a.

[0047] The multilayer substrate 10a differs from the multilayer substrate 10 in that it further includes a third ground conductor layer 30. The third ground conductor layer 30 is located on the lower main surface of the liquid crystal polymer layer 17. The third ground conductor layer 30 covers most of the liquid crystal polymer layer 17. However, the third ground conductor layer 30 is insulated from the signal conductor layer 20. The third ground conductor layer 30 surrounds the periphery of the signal conductor layer 20 when viewed in the vertical direction. The third ground conductor layer 30 is electrically connected to the first ground conductor layer 22 and the second ground conductor layer 24 via interlayer connection conductors v3 and v4. Therefore, the third ground conductor layer 30 is connected to the ground potential. The other structure of the multilayer substrate 10a is the same as that of the multilayer substrate 10, so a description thereof will be omitted. The multilayer substrate 10a can achieve the same functions and effects as the multilayer substrate 10.

[0048] (Second Modification) A multilayer substrate 10b according to a second modified example will be described below with reference to the drawings. Figure 5 is a top view of liquid crystal polymer layers 16a, 17, and 16c of multilayer substrate 10b.

[0049] The multilayer substrate 10b differs from the multilayer substrate 10a in that a plurality of holes ha-hc are provided. More specifically, the third ground conductor layer 30 (second conductor layer) is in contact with the liquid crystal polymer layer 17 (second liquid crystal polymer layer). The third ground conductor layer 30 (second conductor layer) is provided with a plurality of holes ha (first holes) that penetrate the third ground conductor layer 30 (second conductor layer) in the up-down direction (Z-axis direction). At least some of the plurality of holes ha (first holes) have the same size and are arranged at equal intervals. In this embodiment, the plurality of holes ha are arranged in two rows. The plurality of holes ha are arranged in the left-right direction. The area of ​​the holes ha (first holes) as viewed in the up-down direction (Z-axis direction) is smaller than the area of ​​the interlayer connection conductors v1-v4 as viewed in the up-down direction (Z-axis direction). The area of ​​the interlayer connection conductors v1-v4 as viewed in the up-down direction is the area of ​​a region surrounded by the outer edges of the interlayer connection conductors v1-v4 as seen through in the up-down direction. Furthermore, the hole ha is provided only in the third ground conductor layer 30, and is not provided in the liquid crystal polymer layer 17. For example, the hole ha is not a through-hole that passes through the liquid crystal polymer layer 17 in the vertical direction and has a metal provided on the inner circumferential surface thereof.

[0050] The first ground conductor layer 22 (third conductor layer) is in contact with the liquid crystal polymer layer 16a (first liquid crystal polymer layer). The first ground conductor layer 22 (third conductor layer) is provided with a plurality of holes hb (second holes) that penetrate the first ground conductor layer 22 (third conductor layer) in the up-down direction (Z-axis direction). At least some of the plurality of holes hb (second holes) have the same size and are arranged at equal intervals. In this embodiment, the plurality of holes hb are arranged in two rows. The plurality of holes hb are arranged in the left-right direction. The area of ​​the holes hb (second holes) as viewed in the up-down direction (Z-axis direction) is smaller than the area of ​​the holes ha (first holes) as viewed in the up-down direction (Z-axis direction).

[0051] The second ground conductor layer 24 (fourth conductor layer) is in contact with the liquid crystal polymer layer 16c (third liquid crystal polymer layer). The second ground conductor layer 24 (fourth conductor layer) is provided with a plurality of holes hc (third holes) that penetrate the second ground conductor layer 24 (fourth conductor layer) in the up-down direction (Z-axis direction). At least some of the plurality of holes hc (third holes) have the same size and are arranged at equal intervals. In this embodiment, the plurality of holes hc are arranged in two rows. The plurality of holes hc are arranged in the left-right direction. The area of ​​the holes hc (third holes) as viewed in the up-down direction (Z-axis direction) is smaller than the area of ​​the holes ha (first holes) as viewed in the up-down direction (Z-axis direction). The other structure of the multilayer substrate 10b is the same as that of the multilayer substrate 10a, so a description thereof will be omitted. The multilayer substrate 10b can achieve the same effects as the multilayer substrate 10a.

[0052] As described above, the area of ​​hole hb (second hole) viewed in the vertical direction (Z-axis direction) or the area of ​​hole hc (third hole) viewed in the vertical direction (Z-axis direction) is smaller than the area of ​​hole ha (first hole) viewed in the vertical direction (Z-axis direction). This prevents noise from leaking through the liquid crystal polymer layer 16a.

[0053] Furthermore, since the areas of the holes hb in the first ground conductor layer 22 and the holes hc in the second ground conductor layer 24 are small, noise is prevented from radiating from the multilayer substrate 10b and from entering the multilayer substrate 10b. Furthermore, the potentials of the first ground conductor layer 22 and the second ground conductor layer 24 are stabilized at the ground potential.

[0054] (Third Modification) A multilayer substrate 10c according to a third modified example will be described below with reference to the drawings. Fig. 6 is a cross-sectional view of the multilayer substrate 10c. Fig. 7 is a front view of the multilayer substrate 10c when in use.

[0055] The multilayer substrate 10c has a thickness in the vertical direction of the second section A2 that is smaller than the thickness in the vertical direction of the first section A1 and the thickness in the vertical direction of the third section A3. 0 andThe second section A2 differs from the first section A1 in that the liquid crystal polymer layers 16a, 16b, and 17 are absent in the second section A2. This makes the second section A2 more easily deformable than the first section A1 and the third section A3. That is, the second section A2 functions as a flexible region. The first section A1 and the third section A3 function as rigid regions. As shown in FIG. 7, the second section A2 bends downward relative to the first section A1. The rest of the structure of the multilayer substrate 10c is the same as that of the multilayer substrate 10, and therefore a description thereof will be omitted. The multilayer substrate 10c can achieve the same effects as the multilayer substrate 10.

[0056] Furthermore, in the multilayer substrate 10c, the liquid crystal polymer layer 17 with a high elastic modulus is not present in the second section A2. This makes the second section A2 even more flexible. The elastic modulus is measured at room temperature. Room temperature is, for example, between 5°C and 35°C.

[0057] (Fourth Modification) A multilayer substrate 10d according to a fourth modified example will be described below with reference to the drawings. Figure 8 is a cross-sectional view of the multilayer substrate 10d.

[0058] The multilayer substrate 10d differs from the multilayer substrate 10 in that the liquid crystal polymer layer 17 is not provided in the second section A2. As such, the liquid crystal polymer layer 17, which has a high elastic modulus, is not present in the second section A2. This makes the second section A2 even more flexible. The rest of the structure of the multilayer substrate 10d is the same as that of the multilayer substrate 10, so a description thereof will be omitted. The multilayer substrate 10d can achieve the same effects as the multilayer substrate 10.

[0059] (Fifth Modification) A multilayer substrate 10e according to a fifth modified example will be described below with reference to the drawings. Fig. 9 is a cross-sectional view of the multilayer substrate 10e.

[0060] The multilayer substrate 10e differs from the multilayer substrate 10c in that the laminate 12 further includes liquid crystal polymer layers 17a and 17b. More specifically, the liquid crystal polymer layer 17a is laminated on the liquid crystal polymer layer 17. The liquid crystal polymer layer 17b is laminated under the liquid crystal polymer layer 17. In this way, multiple liquid crystal polymer layers with low gas permeability may be provided. This allows the signal conductor layer 20 to be sandwiched between the liquid crystal polymer layers 17 and 17b with low gas permeability from above and below. As a result, corrosion of the signal conductor layer 20 is suppressed. The other structure of the multilayer substrate 10e is the same as that of the multilayer substrate 10, so a description thereof will be omitted. The multilayer substrate 10e has the same structure as the multilayer substrate 10. c The same effect can be achieved.

[0061] (Other embodiments) The multilayer substrate according to the present invention is not limited to multilayer substrates 10, 10a to 10e and can be modified within the scope of the invention. The structures of multilayer substrates 10, 10a to 10e may be combined arbitrarily.

[0062] The protective layers 18a and 18b are not essential components, and either the protective layer 18a or the protective layer 18b may be provided.

[0063] The first ground conductor layer 22 and the second ground conductor layer 24 are not essential components, and either the first ground conductor layer 22 or the second ground conductor layer 24 may be provided.

[0064] The liquid crystal polymer layers 16a-16c and 17 may be made of the same material. In this case, the liquid crystal polymer layers 16a-16c and 17 are made of, for example, a porous material. The porosity of the liquid crystal polymer layer 17 should be lower than that of the liquid crystal polymer layers 16a-16c. This makes the gas permeation rate per unit volume of the liquid crystal polymer layers 16a-16c greater than that of the liquid crystal polymer layer 17. As a result, gas within the laminate 12 is released to the outside of the laminate 12.

[0065] In addition, the first conductor layer may be located only between the liquid crystal polymer layer 16a (first liquid crystal polymer layer) and the liquid crystal polymer layer 17 (second liquid crystal polymer layer) or between the liquid crystal polymer layer 17 (second liquid crystal polymer layer) and the liquid crystal polymer layer 16c (third liquid crystal polymer layer).

[0066] The interlayer connection conductors v1 to v4 do not have to be via-hole conductors. The interlayer connection conductors v1 to v4 may be through-hole conductors. The through-hole conductors are formed by plating the inner circumferential surfaces of through-holes that penetrate the liquid crystal polymer layer in the vertical direction.

[0067] The protective layers 18a and 18b are provided to prevent the conductor layers from being exposed and corroding. Therefore, the gas permeability per unit volume of the protective layers 18a and 18b does not need to be greater than the gas permeability per unit volume of the liquid crystal polymer layers 16a and 16c. Therefore, the gas permeability per unit volume of the protective layers 18a and 18b may be equal to or less than the gas permeability per unit volume of the liquid crystal polymer layers 16a and 16c.

[0068] The interlayer connection conductor v1c may pass through the connection conductor layer 28a (fifth conductor layer) and the signal conductor layer 20 (sixth conductor layer) in the vertical direction (Z-axis direction).

[0069] In the multilayer substrate 10e, a liquid crystal polymer layer may be provided between the liquid crystal polymer layer 17a and the liquid crystal polymer layer 17. Also, a liquid crystal polymer layer may be provided between the liquid crystal polymer layer 17 and the liquid crystal polymer layer 17b. This liquid crystal polymer has a gas permeability greater than the gas permeability per unit volume of the liquid crystal polymer layers 17, 17a, and 17b.

[0070] The holes Ha may be provided in a conductor layer other than the third ground conductor layer 30, as long as they are provided in a conductor layer provided in the laminate 12. [Explanation of symbols]

[0071] 10,10a~10e: Multilayer board 12: Laminate 16a to 16c, 17, 17a, 17b: Liquid crystal polymer layer 18a, 18b: Protective layer 20: Signal conductor layer 22: First ground conductor layer 24: Second ground conductor layer 26a, 26b: Signal terminal 28a, 28b: connecting conductor layers 30: Third ground conductor layer A1: First section A2: Second section A3: Third Section ha~hc: hole v1 to v4, v1a to v1c: Interlayer connection conductors

Claims

1. a laminate in which a plurality of liquid crystal polymer layers including a first liquid crystal polymer layer, a second liquid crystal polymer layer, and a third liquid crystal polymer layer are stacked in the Z-axis direction, the first liquid crystal polymer layer being located in the most positive direction of the Z-axis among the plurality of liquid crystal polymer layers, the third liquid crystal polymer layer being located in the most negative direction of the Z-axis among the plurality of liquid crystal polymer layers, and the second liquid crystal polymer layer being located between the first liquid crystal polymer layer and the third liquid crystal polymer layer in the Z-axis direction; one or more conductor layers provided on the laminate; Equipped with the one or more conductor layers include one or more first conductor layers located between the first liquid crystal polymer layer and the second liquid crystal polymer layer and / or between the second liquid crystal polymer layer and the third liquid crystal polymer layer; the gas permeation amount per unit volume of the first liquid crystal polymer layer and the gas permeation amount per unit volume of the third liquid crystal polymer layer are greater than the gas permeation amount per unit volume of the second liquid crystal polymer layer; the elastic modulus of the first liquid crystal polymer layer and the elastic modulus of the third liquid crystal polymer layer are lower than the elastic modulus of the second liquid crystal polymer layer; Multilayer board.

2. A laminate comprising a plurality of liquid crystal polymer layers including a first liquid crystal polymer layer, a second liquid crystal polymer layer and a third liquid crystal polymer layer stacked in the Z-axis direction, the first liquid crystal polymer layer being located in the most positive direction of the Z-axis among the plurality of liquid crystal polymer layers, the third liquid crystal polymer layer being located in the most negative direction of the Z-axis among the plurality of liquid crystal polymer layers, and the second liquid crystal polymer layer being located between the first liquid crystal polymer layer and the third liquid crystal polymer layer in the Z-axis direction; one or more conductor layers provided on the laminate; Equipped with the one or more conductor layers include one or more first conductor layers located between the first liquid crystal polymer layer and the second liquid crystal polymer layer and / or between the second liquid crystal polymer layer and the third liquid crystal polymer layer; the gas permeation amount per unit volume of the first liquid crystal polymer layer and the gas permeation amount per unit volume of the third liquid crystal polymer layer are greater than the gas permeation amount per unit volume of the second liquid crystal polymer layer; the material of the first liquid crystal polymer layer and the material of the third liquid crystal polymer layer are wholly aromatic polyester resins containing less than 50 mol% of 2-hydroxy-6-naphthoic acid units; the material of the second liquid crystal polymer layer is a wholly aromatic polyester resin containing 50 mol % or more of 2-hydroxy-6-naphthoic acid units; Multilayer board.

3. A laminate comprising a plurality of liquid crystal polymer layers including a first liquid crystal polymer layer, a second liquid crystal polymer layer and a third liquid crystal polymer layer stacked in the Z-axis direction, the first liquid crystal polymer layer being located in the most positive direction of the Z-axis among the plurality of liquid crystal polymer layers, the third liquid crystal polymer layer being located in the most negative direction of the Z-axis among the plurality of liquid crystal polymer layers, and the second liquid crystal polymer layer being located between the first liquid crystal polymer layer and the third liquid crystal polymer layer in the Z-axis direction; one or more conductor layers provided on the laminate; Equipped with the one or more conductor layers include one or more first conductor layers located between the first liquid crystal polymer layer and the second liquid crystal polymer layer and / or between the second liquid crystal polymer layer and the third liquid crystal polymer layer; the gas permeation amount per unit volume of the first liquid crystal polymer layer and the gas permeation amount per unit volume of the third liquid crystal polymer layer are greater than the gas permeation amount per unit volume of the second liquid crystal polymer layer; the one or more first conductor layers include a signal conductor layer through which a high-frequency signal is transmitted; the signal conductor layer is in contact with the second liquid crystal polymer layer; the dielectric loss tangent of the second liquid crystal polymer layer is smaller than the dielectric loss tangent of the first liquid crystal polymer layer and the dielectric loss tangent of the third liquid crystal polymer layer; a first ground conductor layer located in the positive direction of the Z axis from the signal conductor layer and overlapping the signal conductor layer when viewed in the Z axis direction, and / or a second ground conductor layer located in the negative direction of the Z axis from the signal conductor layer and overlapping the signal conductor layer when viewed in the Z axis direction; Multilayer board.

4. a laminate in which a plurality of liquid crystal polymer layers including a first liquid crystal polymer layer, a second liquid crystal polymer layer, and a third liquid crystal polymer layer are stacked in the Z-axis direction, the first liquid crystal polymer layer being located in the most positive direction of the Z-axis among the plurality of liquid crystal polymer layers, the third liquid crystal polymer layer being located in the most negative direction of the Z-axis among the plurality of liquid crystal polymer layers, and the second liquid crystal polymer layer being located between the first liquid crystal polymer layer and the third liquid crystal polymer layer in the Z-axis direction; one or more conductor layers provided on the laminate; Equipped with the one or more conductor layers include one or more first conductor layers located between the first liquid crystal polymer layer and the second liquid crystal polymer layer and / or between the second liquid crystal polymer layer and the third liquid crystal polymer layer; the crystallinity of the second liquid crystal polymer layer is higher than the crystallinity of the first liquid crystal polymer layer and the crystallinity of the third liquid crystal polymer layer; Multilayer board.

5. A laminate comprising a plurality of liquid crystal polymer layers including a first liquid crystal polymer layer, a second liquid crystal polymer layer and a third liquid crystal polymer layer stacked in the Z-axis direction, the first liquid crystal polymer layer being located in the most positive direction of the Z-axis among the plurality of liquid crystal polymer layers, the third liquid crystal polymer layer being located in the most negative direction of the Z-axis among the plurality of liquid crystal polymer layers, and the second liquid crystal polymer layer being located between the first liquid crystal polymer layer and the third liquid crystal polymer layer in the Z-axis direction; one or more conductor layers provided on the laminate; Equipped with the one or more conductor layers include one or more first conductor layers located between the first liquid crystal polymer layer and the second liquid crystal polymer layer and / or between the second liquid crystal polymer layer and the third liquid crystal polymer layer; the gas permeation amount per unit volume of the first liquid crystal polymer layer and the gas permeation amount per unit volume of the third liquid crystal polymer layer are greater than the gas permeation amount per unit volume of the second liquid crystal polymer layer; a first protective layer that does not contain a liquid crystal polymer and covers a main surface of the laminate in the positive direction of the Z axis, and / or a second protective layer that does not contain a liquid crystal polymer and covers a main surface of the laminate in the negative direction of the Z axis, a gas permeation amount per unit volume of the first protective layer and a gas permeation amount per unit volume of the second protective layer are greater than a gas permeation amount per unit volume of the first liquid crystal polymer layer and a gas permeation amount per unit volume of the third liquid crystal polymer layer; an interlayer connection conductor penetrating the second liquid crystal polymer layer in the Z-axis direction; the second liquid crystal polymer layer has a positive principal surface positioned in the positive direction of the Z axis and a negative principal surface positioned in the negative direction of the Z axis; the one or more first conductor layers include a fifth conductor layer located on the positive major surface of the second liquid crystal polymer layer and a sixth conductor layer located on the negative major surface of the second liquid crystal polymer layer; the interlayer connection conductor is in contact with the fifth conductor layer and the sixth conductor layer, and does not penetrate the fifth conductor layer and the sixth conductor layer in the Z-axis direction; Multilayer board.

6. the one or more conductor layers include a second conductor layer; a plurality of first holes penetrating the second conductor layer in the Z-axis direction are provided in the second conductor layer; The multilayer substrate according to claim 1 .

7. At least some of the plurality of first holes have the same size and are arranged at equal intervals. The multilayer substrate according to claim 6 .

8. an interlayer connection conductor that passes through the plurality of liquid crystal polymer layers in the vertical direction; The multilayer substrate according to claim 7 .

9. an area of ​​the first hole as viewed in the Z-axis direction is smaller than an area of ​​the interlayer connection conductor as viewed in the Z-axis direction; The multilayer substrate according to claim 8 .

10. a third conductor layer in contact with the first liquid crystal polymer layer and / or a fourth conductor layer in contact with the third liquid crystal polymer layer; The third conductor layer is provided with a plurality of second holes penetrating the third conductor layer in the Z-axis direction, and / or the fourth conductor layer is provided with a plurality of third holes penetrating the fourth conductor layer in the Z-axis direction. The multilayer substrate according to claim 6 .

11. a third conductor layer in contact with the first liquid crystal polymer layer and / or a fourth conductor layer in contact with the third liquid crystal polymer layer; the one or more first conductor layers include an inner conductor layer in contact with the second liquid crystal polymer layer; the area of ​​the third conductor layer and the area of ​​the fourth conductor layer are larger than the area of ​​the internal conductor layer; The multilayer substrate according to claim 1 .

12. a first protective layer that does not contain a liquid crystal polymer and covers a main surface of the laminate in the positive direction of the Z axis, and / or a second protective layer that does not contain a liquid crystal polymer and covers a main surface of the laminate in the negative direction of the Z axis, The multilayer substrate according to claim 1 .

13. a gas permeation amount per unit volume of the first protective layer and a gas permeation amount per unit volume of the second protective layer are greater than a gas permeation amount per unit volume of the first liquid crystal polymer layer and a gas permeation amount per unit volume of the third liquid crystal polymer layer; The multilayer substrate according to claim 12.

14. the material of the interlayer connection conductor is a mixture of resin and metal; The multilayer substrate according to claim 5 .

15. the elastic modulus of the first liquid crystal polymer layer and the elastic modulus of the third liquid crystal polymer layer are lower than the elastic modulus of the second liquid crystal polymer layer; The multilayer substrate according to claim 4 .

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