Laminated substrate

Abstract

A laminated substrate 1 comprises: a resin layer 10A that has one pair of main surfaces 10Aa, 10Ab facing each other in the thickness direction; a conductor layer 20A that is adjacent to the resin layer 10A on at least one main surface side; and an interlayer connection conductor 30A that penetrates the resin layer 10A in the thickness direction and is connected to the conductor layer 20A. The resin layer 10A includes a first resin material 11a and a second resin material 11b formed from a thermoplastic resin. The Young's modulus of the second resin material 11b is lower than the Young's modulus of the first resin material 11a. The second resin material 11b is dug into the interlayer connection conductor 30A in a plane direction perpendicular to the thickness direction. In the resin layer 10A, the first resin material 11a is dug into the second resin material 11b that is dug into the interlayer connection conductor 30A.

Description

Multilayer substrate

[0001] The present invention relates to a laminated substrate.

[0002] Patent Document 1 discloses a multilayer wiring board in which a via hole is formed in an interlayer insulating layer separating a lower conductor layer and an upper conductor layer, and a via conductor connecting the lower conductor layer and the upper conductor layer is formed in the via hole, wherein the surface of the interlayer insulating layer is rough, the via hole opens in the rough surface of the interlayer insulating layer, the opening edge surrounding the via hole is a stepped portion that is lower than the surrounding area of ​​the opening edge, and the surface roughness of the stepped portion is greater than the surface roughness of the surrounding area.

[0003] JP 2012-142559 A

[0004] In a laminated substrate, cracks may occur in the interlayer connection conductors (via conductors in Patent Document 1) due to external stress, temperature environment, etc., and in some cases, the connection reliability of the interlayer connection conductors may decrease (e.g., poor conductivity may occur).

[0005] In contrast, in the multilayer wiring board described in Patent Document 1, a step portion is formed at the opening edge of the via hole in the interlayer insulating layer, and further, the surface roughness of the step portion is greater than the surface roughness of the surrounding area, so that it is possible to ensure adhesion between the upper conductor layer and the interlayer insulating layer and to increase the adhesion strength between the upper conductor layer and the interlayer insulating layer. As a result, it is possible to suppress delamination at the connection portion between the via conductor and the upper conductor layer in the multilayer wiring board described in Patent Document 1, and it is possible to improve the connection reliability of the via conductor.

[0006] However, the inventors have conducted research and found that in the multilayer wiring board described in Patent Document 1, the surface roughness of the via holes formed in the interlayer insulating layer is small, resulting in insufficient adhesion between the via conductors formed in the via holes and the interlayer insulating layer, and as a result, the via conductors are prone to peeling off from the interlayer insulating layer.

[0007] The present invention has been made to solve the above problems, and has as its object to provide a laminated substrate in which interlayer connection conductors are less likely to peel off from resin layers.

[0008] The laminated substrate of the present invention comprises a resin layer having a pair of main surfaces opposing each other in a thickness direction, a conductor layer adjacent to at least one of the main surfaces of the resin layer, and an interlayer connection conductor connected to the conductor layer while penetrating the resin layer in the thickness direction, wherein the resin layer contains a first resin material and a second resin material made of a thermoplastic resin, the Young's modulus of the second resin material being lower than the Young's modulus of the first resin material, the second resin material biting into the interlayer connection conductor in a plane direction perpendicular to the thickness direction, and the first resin material biting into the second resin material biting into the interlayer connection conductor within the resin layer.

[0009] According to the present invention, it is possible to provide a laminated substrate in which the interlayer connection conductors are not easily peeled off from the resin layer.

[0010] FIG. 1 is a cross-sectional view schematically illustrating an example of a laminated substrate according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view schematically illustrating the laminated substrate shown in FIG. 1 , and is a cross-sectional view for explaining a method for determining whether or not the second resin material has bitten into the interlayer connection conductor. FIG. 3 is an enlarged cross-sectional view schematically illustrating the laminated substrate shown in FIG. 1 , and is a cross-sectional view for explaining a method for determining the protrusion angle of the convex portion. FIG. 4 is a cross-sectional view schematically illustrating a step of producing a resin sheet with a conductor layer in an example of a method for manufacturing a laminated substrate according to a first embodiment of the present invention. FIG. 5 is a cross-sectional view schematically illustrating a step of forming a through hole in an example of a method for manufacturing a laminated substrate according to a first embodiment of the present invention. FIG. 6 is a cross-sectional view schematically illustrating a step of filling a conductive paste in an example of a method for manufacturing a laminated substrate according to a first embodiment of the present invention. FIG. 7 is a cross-sectional view schematically illustrating a step of forming an interlayer connection conductor in an example of a method for manufacturing a laminated substrate according to a first embodiment of the present invention. FIG. 8 is an example of a cross-sectional image showing an enlarged view of the laminated substrate according to the first embodiment of the present invention. FIG. 9 is a cross-sectional view schematically illustrating an example of a laminated substrate according to a second embodiment of the present invention. Fig. 10 is a cross-sectional view schematically showing an example of a laminated substrate according to Embodiment 3 of the present invention. Fig. 11 is a cross-sectional view schematically showing an example of a laminated substrate according to Embodiment 4 of the present invention. Fig. 12 is a cross-sectional view schematically showing an example of a laminated substrate according to Embodiment 5 of the present invention.

[0011] The laminated substrate of the present invention will be described below. Note that the present invention is not limited to the following configurations and may be modified as appropriate within the scope of the present invention. In addition, a combination of multiple individual preferred configurations described below also constitutes the present invention.

[0012] The following embodiments are merely examples, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible. From embodiment 2 onwards, descriptions of matters common to embodiment 1 will be omitted, and differences will be mainly described. In particular, similar effects resulting from similar configurations will not be mentioned one after the other for each embodiment.

[0013] In the following description, when there is no need to particularly distinguish between the embodiments, they will simply be referred to as "the laminated substrate of the present invention."

[0014] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, scale, etc. may differ from those of the actual product.

[0015] In this specification, unless otherwise specified, terms indicating the relationship between elements (e.g., "parallel," "perpendicular," etc.) and terms indicating the shape of elements not only mean the literal strict form, but also mean a range that is substantially equivalent, for example, a range that includes a difference of about a few percent.

[0016] The laminated substrate of the present invention comprises a resin layer having a pair of main surfaces opposing each other in a thickness direction, a conductor layer adjacent to at least one of the main surfaces of the resin layer, and an interlayer connection conductor connected to the conductor layer while penetrating the resin layer in the thickness direction, wherein the resin layer contains a first resin material and a second resin material made of a thermoplastic resin, the Young's modulus of the second resin material being lower than the Young's modulus of the first resin material, the second resin material biting into the interlayer connection conductor in a plane direction perpendicular to the thickness direction, and the first resin material biting into the second resin material biting into the interlayer connection conductor within the resin layer.

[0017] First Embodiment FIG. 1 is a cross-sectional view schematically illustrating an example of a laminated substrate according to a first embodiment of the present invention.

[0018] The laminated substrate 1 shown in FIG. 1 includes a resin layer 10A, a conductor layer 20A, and an interlayer connection conductor 30A.

[0019] The resin layer 10A has a pair of principal surfaces that face each other in the thickness direction (the vertical direction in FIG. 1 ). In the example shown in FIG. 1 , the resin layer 10A has a first principal surface 10Aa and a second principal surface 10Ab that face each other in the thickness direction.

[0020] The resin layer 10A includes a first resin material 11a and a second resin material 11b.

[0021] The first resin material 11a is preferably made of a thermoplastic resin.

[0022] When the first resin material 11a is made of a thermoplastic resin, examples of the thermoplastic resin that constitutes the first resin material 11a include liquid crystal polymer (LCP), thermoplastic polyimide (TPI), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), etc.

[0023] The first resin material 11a is preferably made of a liquid crystal polymer. Since liquid crystal polymers have a low relative dielectric constant among thermoplastic resins, when the first resin material 11a is made of a liquid crystal polymer, the dielectric properties in the high frequency range of the laminated substrate 1 are likely to be improved. Furthermore, since liquid crystal polymers have low hygroscopicity, when the first resin material 11a is made of a liquid crystal polymer, changes in the dielectric properties of the laminated substrate 1 due to moisture absorption are less likely to occur.

[0024] When the first resin material 11a is made of a liquid crystal polymer, the liquid crystal polymer constituting the first resin material 11a preferably contains a copolymer of p-hydroxybenzoic acid (HBA) and 6-hydroxy-2-naphthoic acid (HNA).

[0025] Copolymers of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are generally referred to as type II wholly aromatic polyesters (also referred to as type 1.5 wholly aromatic polyesters). Type II wholly aromatic polyesters are less susceptible to hydrolysis than type III partially aromatic polyesters, and are therefore preferred as constituent materials for the laminate substrate 1. Furthermore, type II wholly aromatic polyesters have a low dielectric loss tangent due to the naphthalene ring, and therefore contribute to reducing electrical energy loss in the resin layer 10A in the laminate substrate 1.

[0026] When the first resin material 11a is made of a liquid crystal polymer, the liquid crystal polymer constituting the first resin material 11a may further contain, in addition to the type II wholly aromatic polyester, a type I wholly aromatic polyester, or may further contain a type III partially aromatic polyester, or may further contain a type I wholly aromatic polyester and a type III partially aromatic polyester.

[0027] The structure (type) of each monomer constituting the liquid crystal polymer can be analyzed by reactive pyrolysis gas chromatography mass spectrometry (reactive pyrolysis GC-MS method).

[0028] The first resin material 11a may be made of a thermosetting resin.

[0029] The thermal expansion coefficient of the first resin material 11a in the planar direction is preferably smaller than the thermal expansion coefficient of the conductor layer 20A in the planar direction. In this case, the difference between the thermal expansion coefficient of the first resin material 11a in the planar direction and the thermal expansion coefficient of the conductor layer 20A in the planar direction is preferably 2 ppm / °C or more and 10 ppm / °C or less.

[0030] The second resin material 11b is made of a thermoplastic resin.

[0031] Examples of thermoplastic resins that make up the second resin material 11b include perfluoroalkoxyalkane (PFA) (fluorine-containing resin), thermoplastic polyimide (TPI), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene ether (PPE), polymethylpentene (PMP), cross-linked polyethylene (XLPE), and polynorbornene (PNB).

[0032] The second resin material 11b is preferably made of a perfluoroalkoxyalkane. Because perfluoroalkoxyalkanes have a lower dielectric constant than liquid crystal polymers, using a perfluoroalkoxyalkane for the second resin material 11b improves the dielectric properties of the laminate substrate 1 in the high frequency range. Furthermore, because perfluoroalkoxyalkanes, like liquid crystal polymers, have low hygroscopicity, using a perfluoroalkoxyalkane for the second resin material 11b reduces the likelihood of changes in the dielectric properties of the laminate substrate 1 due to moisture absorption. Furthermore, because perfluoroalkoxyalkanes have a high heat resistance temperature of 260°C or higher, using a perfluoroalkoxyalkane for the second resin material 11b reduces the likelihood of damage to the laminate substrate 1 when the laminate substrate 1 is incorporated into an electronic device by reflow soldering, for example.

[0033] Alternatively, the second resin material 11b is preferably made of polyphenylene ether. Because polyphenylene ether has a low relative permittivity and dielectric dissipation factor similar to perfluoroalkoxyalkanes, the dielectric properties of the laminate substrate 1 in the high frequency range are likely to be improved by using polyphenylene ether for the second resin material 11b. Furthermore, because polyphenylene ether has low hygroscopicity similar to perfluoroalkoxyalkanes, using polyphenylene ether for the second resin material 11b makes it less likely for the dielectric properties of the laminate substrate 1 to change due to moisture absorption. Furthermore, because polyphenylene ether has a smaller thermal expansion coefficient than perfluoroalkoxyalkanes, using polyphenylene ether for the second resin material 11b makes it less likely for the laminate substrate 1 to change in dimension. Furthermore, because polyphenylene ether has a higher tensile strength (e.g., tensile elongation at break) than perfluoroalkoxyalkanes, using polyphenylene ether for the second resin material 11b increases the strength of the laminate substrate 1.

[0034] The type of resin material present in the resin layer is identified as follows: First, the laminated substrate is polished to expose a cross section along the thickness direction. Then, the cross section of the laminated substrate is analyzed using a microscopic Fourier transform infrared spectrophotometer (microscopic FT-IR), thereby identifying the type of resin material present in the resin layer.

[0035] The second resin material 11b is preferably dispersed in the first resin material 11a, in which case the second resin material 11b functions as a filler for the first resin material 11a and is easily bound by the first resin material 11a.

[0036] The Young's modulus of the second resin material 11b is lower than that of the first resin material 11a, that is, the second resin material 11b is more easily deformed by an external force (has lower rigidity) than the first resin material 11a.

[0037] The magnitude relationship of the Young's moduli of the resin materials present in the resin layer is determined by one of the following methods: (1) The magnitude relationship of the Young's moduli of the resin materials is determined by looking up the general Young's moduli of the resin materials identified by the above-mentioned method in publicly available literature such as a dictionary. (2) The magnitude relationship of the Young's moduli of the resin materials present in the resin layer is determined by measuring the Young's moduli of the resin materials using an atomic force microscope (AFM), which is a type of scanning probe microscope (SPM). (3) When polishing the laminated substrate (resin layer), the magnitude relationship of the Young's moduli of the resin materials is determined by checking the ease or difficulty of polishing the resin materials. Specifically, a resin material that is easy to polish is determined to have a lower Young's modulus than a resin material that is difficult to polish. In other words, a resin material that is difficult to polish is determined to have a higher Young's modulus than a resin material that is easy to polish.

[0038] The above methods (1) and (2) allow the magnitude relationship of the Young's modulus of the resin materials to be determined by using the absolute values ​​of the Young's modulus of the resin materials, whereas the above method (3) allows the magnitude relationship of the Young's modulus of the resin materials to be determined without using the absolute values ​​of the Young's modulus of the resin materials.

[0039] The second resin material 11b preferably has a flat shape.

[0040] When a resin material is flat, it means that the aspect ratio of the resin material is 3 or more when viewed in a cross section along the thickness direction of the resin layer, and preferably means that the aspect ratio of the resin material is 3 or more and 30 or less.

[0041] The aspect ratio of the resin material is determined as follows. First, the laminated substrate is polished to expose a cross section along the thickness direction. Next, a scanning electron microscope (SEM) is used to image the cross section along the thickness direction of the resin layer. Next, image analysis software is used to draw an ellipse with the smallest area circumscribing the resin material in the cross-sectional image of the resin layer. Then, for the drawn ellipse, the major axis dimension / minor axis dimension is calculated, and this is determined as the aspect ratio of the resin material.

[0042] The melting point of the second resin material 11b is preferably lower than that of the first resin material 11a. In this case, the difference between the melting points of the first resin material 11a and the second resin material 11b is preferably 10°C or more and 200°C or less.

[0043] The melting point of a resin material is determined as follows. First, a resin layer is extracted from a laminate substrate by removing the conductor layer by peeling, etching, or other methods. Then, the target resin material is extracted from the resin layer by scraping, or other methods. Thereafter, the melting point of the target resin material is measured using a differential scanning calorimeter (DSC). Note that, if the melting point of the target resin material cannot be clearly measured using the above-mentioned method, or if the target resin material is an amorphous resin material, the glass transition temperature (Tg) may be used instead.

[0044] The thermal expansion coefficient of the second resin material 11b in the in-plane direction is preferably greater than the thermal expansion coefficient of the first resin material 11a in the in-plane direction. In this case, the difference between the thermal expansion coefficient of the first resin material 11a in the in-plane direction and the thermal expansion coefficient of the second resin material 11b in the in-plane direction is preferably 30 ppm / °C or more and 120 ppm / °C or less.

[0045] The thermal expansion coefficient of the first resin material 11a in the planar direction is preferably smaller than the thermal expansion coefficient of the conductor layer 20A in the planar direction. In this case, the difference between the thermal expansion coefficient of the first resin material 11a in the planar direction and the thermal expansion coefficient of the conductor layer 20A in the planar direction is preferably 2 ppm / °C or more and 10 ppm / °C or less.

[0046] The thermal expansion coefficient of the second resin material 11b in the planar direction is preferably greater than the thermal expansion coefficient of the conductor layer 20A in the planar direction. In this case, the difference between the thermal expansion coefficient of the second resin material 11b in the planar direction and the thermal expansion coefficient of the conductor layer 20A in the planar direction is preferably 30 ppm / °C or more and 110 ppm / °C or less.

[0047] When the conductor layer 20A is made of copper foil, the thermal expansion coefficient of the conductor layer 20A in the plane direction is about 16 ppm / °C.

[0048] The thermal expansion coefficient of the resin material present in the resin layer in the in-plane direction is determined as follows. First, the target resin layer is extracted from the laminate substrate by removing the conductor layer, etc., using methods such as peeling or etching. Then, the thermal expansion coefficient of the target resin layer in the in-plane direction is measured using thermomechanical analysis (TMA). For example, a 20 mm long x 4 mm wide resin layer sample is cut out, and the resin layer sample is heated and then cooled under the following measurement conditions: tensile mode, 10 mm chuck distance, 5 g load, 40°C / min heating rate, and 10°C / min cooling rate. The change in chuck distance during the cooling process is measured over a temperature range from 100°C to 50°C, thereby determining the thermal expansion coefficient of the target resin layer sample in the in-plane direction. Next, the elastic modulus of the target resin layer sample is measured using dynamic mechanical analysis (DMA) in the tensile mode. Meanwhile, the type of resin material present in the target resin layer sample is identified for a cross section along the thickness direction of the target resin layer sample using the above-mentioned method. Then, for example, image analysis software is used to measure the area ratio of the target resin material (e.g., the first resin material or the second resin material) in the cross section of the target resin layer sample. Furthermore, the elastic modulus of the target resin material in the cross section of the target resin layer sample is measured using the elastic modulus measurement mode of a scanning probe microscope (SPM). Based on the measurement data obtained as described above, the thermal expansion coefficient of the target resin material in the in-plane direction is calculated according to the area ratio and elastic modulus of the target resin material from the thermal expansion coefficient of the target resin layer sample in the in-plane direction. For example, in the case of using a sample of a resin layer 10A including a first resin material 11a and a second resin material 11b, the thermal expansion coefficient in the plane direction of the first resin material 11a is CTE1 (unit: ppm / °C), the thermal expansion coefficient in the plane direction of the second resin material 11b is CTE2 (unit: ppm / °C), the thermal expansion coefficient in the plane direction of the sample of the resin layer 10A is CTEt (unit: ppm / °C), the elastic modulus of the first resin material 11a is E1 (unit: GPa), the elastic modulus of the second resin material 11b is E2 (unit: GPa), the elastic modulus of the sample of the resin layer 10A is Et (unit: GPa), the area ratio of the first resin material 11a is V1 (unit: %), and the area ratio of the second resin material 11b is V2 (unit: %), then the following formula (A) holds as a stress-neutral relationship.CTE1×E1×V1+CTE2×E2×V2=CTEt×Et×(V1+V2) (A) Here, CTEt, E1, E2, Et, V1, and V2 are measured by the method described above. Furthermore, CTE2 is measured by the following method. First, the sample of the resin layer 10A is treated with a strong alkali to remove the first resin material 11a from the sample of the resin layer 10A. Then, the second resin material 11b (a mass of multiple irregular shapes) taken out of the sample of the resin layer 10A is subjected to hot pressing (pressure, for example, 2 MPa or more and 3 MPa or less) at a temperature 20°C lower than the melting point of the second resin material 11b and lower than the melting point of the second resin material 11b (i.e., (Tm2-20) or more and Tm2 or less), to produce a resin sheet made of the second resin material 11b with a thickness of 50 μm or more and 500 μm or less. Thereafter, the thermal expansion coefficient CTE2 in the plane direction of the resin sheet made of the second resin material 11b is measured by thermomechanical analysis. Using the CTE2, CTEt, E1, E2, Et, V1, and V2 obtained as described above, CTE1 is calculated from the following formula (B), which is obtained by modifying the above formula (A). CTE1=[CTEt×Et×(V1+V2)−CTE2×E2×V2] / [E1×V1] (B).

[0049] The thermal expansion coefficient of a conductor layer in the planar direction is determined as follows. First, a target conductor layer is removed from a laminate substrate by peeling or other methods. Then, the thermal expansion coefficient of the target conductor layer in the planar direction is measured by thermomechanical analysis. When measuring the thermal expansion coefficient of the conductor layer in the planar direction, the same measurement conditions are used as when measuring the thermal expansion coefficient of the resin layer in the planar direction, for example.

[0050] The relative dielectric constant of the second resin material 11b is preferably lower than the relative dielectric constant of the first resin material 11a.

[0051] The relative permittivity of the resin material present in the resin layer is determined as follows. For example, when a resin layer 10A containing a first resin material 11a and a second resin material 11b is used as a sample, the resin layer 10A is first treated with a strong alkali to extract the second resin material 11b. The extracted second resin material 11b is then molded into a sheet having a thickness of 50 μm or more and 500 μm or less to obtain a resin sheet sample. The relative permittivity of the second resin material 11b is then measured using a dielectric resonator method (TE011 mode, frequency range: 12 GHz or more and 60 GHz or less). Next, the relative permittivity of the resin layer 10A is measured using the dielectric resonator method under the same conditions as above. Furthermore, an X-ray CT scanner is used to identify the three-dimensional structure of the first resin material 11a and the second resin material 11b in the resin layer 10A, and then analysis software is used to measure the volume ratio of the first resin material 11a and the second resin material 11b in the resin layer 10A. Then, from the relative dielectric constant of the resin layer 10A and the relative dielectric constant of the second resin material 11b measured by the above-mentioned method, the relative dielectric constant of the first resin material 11a is calculated according to the volume ratio of the first resin material 11a and the second resin material 11b in the resin layer 10A.

[0052] The dielectric loss tangent of the second resin material 11b is preferably lower than the dielectric loss tangent of the first resin material 11a.

[0053] The dielectric loss tangent of the resin material present in the resin layer is determined as follows. For example, when a resin layer 10A containing a first resin material 11a and a second resin material 11b is used as a sample, the resin layer 10A is first treated with a strong alkali to extract the second resin material 11b. The extracted second resin material 11b is then molded into a sheet having a thickness of 50 μm or more and 500 μm or less to obtain a resin sheet sample. The dielectric loss tangent of the second resin material 11b is then measured using a dielectric resonator method (TE011 mode, frequency range: 12 GHz or more and 60 GHz or less). Next, the dielectric loss tangent of the resin layer 10A is measured using the dielectric resonator method under the same conditions as above. Furthermore, an X-ray CT scanner is used to identify the three-dimensional structure of the first resin material 11a and the second resin material 11b in the resin layer 10A, and then analysis software is used to measure the volume ratio of the first resin material 11a to the second resin material 11b in the resin layer 10A. Then, from the dielectric tangent of the resin layer 10A and the dielectric tangent of the second resin material 11b measured by the above-mentioned method, the dielectric tangent of the first resin material 11a is calculated according to the volume ratio of the first resin material 11a and the second resin material 11b in the resin layer 10A.

[0054] The adhesion between the second resin materials 11b (e.g., tensile elongation at break) is preferably higher than the adhesion between the first resin materials 11a (e.g., tensile elongation at break). The first resin material 11a mainly serves to impart rigidity to the resin layer 10A and suppress dimensional changes in the resin layer 10A. On the other hand, the second resin material 11b mainly serves to improve the dielectric properties of the resin layer 10A and impart flexibility to the resin layer 10A. Therefore, if the adhesion between the second resin materials 11b is higher than the adhesion between the first resin materials 11a, the bending processability of the laminated substrate 1 is likely to be improved.

[0055] The magnitude relationship of the adhesion (e.g., tensile elongation at break) between resin materials of the same type present in a resin layer is determined as follows. First, a tensile stress is applied to the resin layer by pulling the resin layer in a laminated substrate. At this time, for example, after removing the resin layer from the laminated substrate, a tensile test of the resin layer is performed in accordance with "JIS K 7127-1999." Then, when tensile stress is applied to the resin layer, it is confirmed which resin material breaks first. At this time, if the first resin material 11a breaks before the second resin material 11b breaks, it is determined that the adhesion (e.g., tensile elongation at break) between the second resin materials 11b is higher than the adhesion (e.g., tensile elongation at break) between the first resin materials 11a.

[0056] In addition to the first resin material 11a and the second resin material 11b, the resin layer 10A may further contain other materials (e.g., resin materials). In this case, for example, the content of the first resin material 11a is the largest in the resin layer 10A, and the content of the second resin material 11b is the next largest. The content ratios of the resin materials are determined, for example, by using image analysis software to measure the area ratios of the resin materials in a cross-sectional image taken along the thickness direction of the resin layer.

[0057] The conductor layer 20A is adjacent to one of the main surfaces of the resin layer 10A. In the example shown in Fig. 1, the conductor layer 20A is adjacent to the first main surface 10Aa of the resin layer 10A.

[0058] The conductor layer 20A may be in the form of a surface extending over the entire first main surface 10Aa of the resin layer 10A, or may be in the form of a pattern patterned into wiring or the like on a portion of the first main surface 10Aa of the resin layer 10A.

[0059] Examples of materials that can be used to form the conductor layer 20A include copper, silver, aluminum, stainless steel, nickel, gold, and alloys containing at least one of these metals.

[0060] The conductor layer 20A is made of, for example, a metal foil, and is preferably made of copper foil among other metal foils. In this case, a metal other than copper may be present on the surface of the copper foil.

[0061] The thickness of the conductor layer 20A is preferably 1 μm or more and 35 μm or less, and more preferably 6 μm or more and 18 μm or less.

[0062] The interlayer connection conductor 30A penetrates the resin layer 10A in the thickness direction and is connected to the conductor layer 20A. In the example shown in Fig. 1, the interlayer connection conductor 30A penetrates the resin layer 10A in the thickness direction but does not penetrate the conductor layer 20A in the thickness direction and is connected to the conductor layer 20A.

[0063] When viewed in a cross section along the thickness direction, the width of the interlayer connection conductor 30A may decrease, increase, or remain constant from the conductor layer 20A side toward the opposite side of the conductor layer 20A as shown in Fig. 1. In other words, when viewed in a cross section perpendicular to the thickness direction, the cross-sectional area of ​​the interlayer connection conductor 30A may decrease, increase, or remain constant from the conductor layer 20A side toward the opposite side of the conductor layer 20A.

[0064] The interlayer connection conductor 30A is formed, for example, by filling a through hole that penetrates the resin layer 10A in the thickness direction with a conductive paste and then performing a heat treatment, a plating treatment on the inner wall, or a sputtering treatment on the inner wall.

[0065] When the interlayer connection conductor 30A is formed by heat treatment of a conductive paste, examples of the metal contained in the interlayer connection conductor 30A include copper, tin, silver, etc. Among these, the interlayer connection conductor 30A preferably contains copper, and more preferably contains copper and tin. For example, when the interlayer connection conductor 30A contains copper and tin and the conductor layer 20A is made of copper foil, the interlayer connection conductor 30A and the conductor layer 20A undergo an alloying reaction at low temperatures, making the two more likely to be electrically connected.

[0066] When the interlayer connection conductor 30A is formed by heat treatment of a conductive paste, it is preferable that the resin contained in the interlayer connection conductor 30A includes at least one thermosetting resin selected from the group consisting of epoxy resin, phenolic resin, polyimide resin, silicone resin or modified resin thereof, and acrylic resin, or at least one thermoplastic resin selected from the group consisting of polyamide resin, polystyrene resin, polymethacrylic resin, polycarbonate resin, and cellulose-based resin.

[0067] When the interlayer connection conductor 30A is formed by plating, examples of the metal constituting the interlayer connection conductor 30A include copper, tin, silver, etc. Among these, it is preferable that the interlayer connection conductor 30A contains copper.

[0068] When the interlayer connection conductor 30A is formed by sputtering, examples of the metal constituting the interlayer connection conductor 30A include copper, tin, silver, etc. Among these, it is preferable that the interlayer connection conductor 30A contains copper.

[0069] The laminated substrate 1 may further include a conductor layer 20B.

[0070] In the example shown in FIG. 1, the conductor layer 20B is adjacent to the second main surface 10Ab side of the resin layer 10A.

[0071] 1, the conductor layer 20B is connected to the interlayer connection conductor 30A. That is, the conductor layer 20B is electrically connected to the conductor layer 20A via the interlayer connection conductor 30A.

[0072] The conductor layer 20B may be in the form of a surface extending over the entire second main surface 10Ab of the resin layer 10A, or may be in the form of a pattern patterned into wiring or the like on a portion of the second main surface 10Ab of the resin layer 10A.

[0073] The constituent material of the conductor layer 20B may be the same as or different from the constituent material of the conductor layer 20A.

[0074] The thickness of the conductor layer 20B may be the same as or different from the thickness of the conductor layer 20A.

[0075] In the laminated substrate 1, the second resin material 11b penetrates into the interlayer connection conductor 30A in a planar direction perpendicular to the thickness direction (the left-right direction in FIG. 1 ). In the example shown in FIG. 1 , the second resin material 11b protrudes further toward the interlayer connection conductor 30A than the first resin material 11a in the planar direction. This results in an uneven surface on the interlayer connection conductor 30A side of the resin layer 10A. The interlayer connection conductor 30A is provided so as to follow the unevenness of the surface on the interlayer connection conductor 30A side of the resin layer 10A. Specifically, the interlayer connection conductor 30A is provided so as to be in contact with the first resin material 11a and the second resin material 11b.

[0076] In the laminated substrate 1, the second resin material 11b is embedded in the interlayer connection conductor 30A, thereby providing an anchor effect, which makes it difficult for the interlayer connection conductor 30A to peel off from the resin layer 10A (particularly the second resin material 11b).

[0077] Furthermore, in the laminate substrate 1, the second resin material 11b, which penetrates into the interlayer connection conductor 30A, has a lower Young's modulus than the first resin material 11a, i.e., it is more easily deformed by external forces than the first resin material 11a. Therefore, even if stress (thermal stress, bending stress, etc.) occurs at the interface between the resin layer 10A and the interlayer connection conductor 30A when the laminate substrate 1 is heated or bent, the second resin material 11b acts as a buffer material, easily alleviating the stress. In particular, in the laminate substrate 1, because the second resin material 11b is made of a thermoplastic resin, even if stress occurs at the interface between the resin layer 10A and the interlayer connection conductor 30A when the laminate substrate 1 is heated, the second resin material 11b acts as a buffer material, easily alleviating the stress. As a result, even if stress occurs at the interface between the resin layer 10A and the interlayer connection conductor 30A in the laminate substrate 1, cracks are suppressed in the interlayer connection conductor 30A, and the connection reliability of the interlayer connection conductor 30A is less likely to decrease.

[0078] Whether or not the second resin material 11b has bitten into the interlayer connection conductor 30A is determined as follows.

[0079] FIG. 2 is an enlarged cross-sectional view schematically showing the laminated substrate shown in FIG. 1, and is a cross-sectional view for explaining a method for determining whether or not the second resin material has bitten into the interlayer connection conductors.

[0080] First, the laminated substrate 1 is polished to expose a cross section along the thickness direction, as shown in FIG. 2 . Next, a scanning electron microscope is used to image the cross section along the thickness direction of the laminated substrate 1. In the obtained cross-sectional image of the laminated substrate 1, endpoints E1 and E2 located on the interlayer connection conductor 30A side in the surface direction of the interface between the resin layer 10A and the conductor layer 20B are determined, and a line L1 connecting the endpoints E1 and E2 is drawn. Next, a midpoint F1 of the line L1 is determined, and a line L2 perpendicular to the line L1 is drawn from the midpoint F1. Then, a distance G1 in the surface direction from the line L2 to the resin layer 10A is measured while changing the position in the thickness direction. If the distance G1 changes from decreasing to increasing, it is determined that the resin layer 10A is embedded in the interlayer connection conductor 30A. Furthermore, by confirming using the method described above that the second resin material 11b is present in the portion where the resin layer 10A has penetrated into the interlayer connection conductor 30A, it is determined that the second resin material 11b has penetrated into the interlayer connection conductor 30A.

[0081] In determining whether the second resin material 11b has penetrated into the interlayer connection conductor 30A, instead of drawing the line L1 connecting the end points E1 and E2 as described above, two end points located on the interlayer connection conductor 30A side in the planar direction of the interface between the resin layer 10A and the conductor layer 20A may be determined, and a line connecting these two end points may be drawn. After that, it is sufficient to determine whether the second resin material 11b has penetrated into the interlayer connection conductor 30A in the same manner as described above.

[0082] Furthermore, in the laminated substrate 1, the first resin material 11a bites into the second resin material 11b that bites into the interlayer connection conductor 30A within the resin layer 10A. Strictly speaking, the second resin material 11b that bites into the interlayer connection conductor 30A has biting portions 11ba that substantially bite into the interlayer connection conductor 30A and non-biting portions 11bb that do not substantially bite into the interlayer connection conductor 30A. The first resin material 11a bites into the non-biting portions 11bb within the resin layer 10A.

[0083] The manner in which the first resin material 11a penetrates into the second resin material 11b includes a manner in which the first resin material 11a penetrates into one second resin material 11b, and a manner in which the first resin material 11a penetrates into the gaps between multiple second resin materials 11b, some of which are in contact with each other.

[0084] In the laminate substrate 1, the first resin material 11a penetrates into the second resin material 11b, which penetrates into the interlayer connection conductor 30A, within the resin layer 10A, making it easier for the first resin material 11a to support the second resin material 11b. Here, if the first resin material 11a is made of a thermosetting resin, the first resin material 11a easily supports the second resin material 11b, even when heated. In this way, in the laminate substrate 1, when the first resin material 11a supports the second resin material 11b, the second resin material 11b is less likely to move when the second resin material 11b penetrates into the interlayer connection conductor 30A. Therefore, in the laminate substrate 1, the anchor effect of the second resin material 11b is further enhanced, and as a result, the interlayer connection conductor 30A is even less likely to peel off from the resin layer 10A.

[0085] Whether the first resin material 11a has penetrated into the second resin material 11b, which has penetrated into the interlayer connecting conductor 30A, within the resin layer 10A can be determined by examining a cross section along the thickness direction of the laminated substrate 1 using a scanning electron microscope.

[0086] In the laminate substrate 1, when viewed in a cross section along the thickness direction, if the portions where the second resin material 11b bites into the interlayer connection conductor 30A are defined as protrusions 12 (the same portions as biting portions 11ba), the total number of protrusions 12 at a pair of interfaces (left and right interfaces in FIG. 1 ) between the resin layer 10A and the interlayer connection conductor 30A is preferably 3 to 20. In this case, when the laminate substrate 1 is viewed as a whole across the pair of interfaces between the resin layer 10A and the interlayer connection conductor 30A, the anchor effect of the protrusions 12 (second resin material 11b) is further enhanced, making the interlayer connection conductor 30A even less likely to peel off from the resin layer 10A.

[0087] If the total number of protrusions 12 at a pair of interfaces between the resin layer 10A and the interlayer connection conductor 30A is less than three, there will be fewer protrusions 12 that function as anchors, and there is a risk that the anchor effect of the protrusions 12 will not be fully exerted.

[0088] If the total number of protrusions 12 at a pair of interfaces between the resin layer 10A and the interlayer connecting conductor 30A is greater than 20, the spacing between the protrusions 12 becomes narrower, making it difficult for the conductor layer 20A to penetrate between the protrusions 12, and there is a risk that the anchoring effect of the protrusions 12 will not be fully exerted.

[0089] In the laminate substrate 1, it is preferable that the number of protrusions 12 at one of a pair of interfaces between the resin layer 10A and the interlayer connection conductor 30A is 2 or more and 10 or less. In this case, when viewing one of the interfaces between the resin layer 10A and the interlayer connection conductor 30A in the laminate substrate 1, the anchor effect of the protrusions 12 is further enhanced, making it even more difficult for the interlayer connection conductor 30A to peel off from the resin layer 10A.

[0090] If the number of protrusions 12 at one interface between the resin layer 10A and the interlayer connection conductor 30A is less than two, there will be fewer protrusions 12 that function as anchors, and there is a risk that the anchor effect of the protrusions 12 will not be fully exerted.

[0091] If the number of protrusions 12 at one interface between the resin layer 10A and the interlayer connection conductor 30A is greater than 10, the spacing between the protrusions 12 becomes narrower, making it difficult for the conductor layer 20A to penetrate between the protrusions 12, and there is a risk that the anchor effect of the protrusions 12 will not be fully exerted.

[0092] Similarly, the number of protrusions 12 at the other interface of the pair of interfaces between the resin layer 10A and the interlayer connection conductor 30A is preferably 2 or more and 10 or less.

[0093] In view of the above, it is preferable that the number of protrusions 12 at each interface between the resin layer 10A and the interlayer connection conductor 30A is 2 or more and 10 or less.

[0094] In the laminated substrate 1, when viewed in a cross section along the thickness direction, if the portion where the second resin material 11b has embedded into the interlayer connection conductor 30A is defined as the convex portion 12 (the same portion as the embedded portion 11ba), it is preferable that the protrusion angle at which the convex portion 12 protrudes toward the interlayer connection conductor 30A is greater than or equal to 20° and less than or equal to 80°.

[0095] The protruding angle of the convex portion 12 is determined as follows.

[0096] FIG. 3 is an enlarged cross-sectional view schematically showing the laminated substrate shown in FIG. 1, and is a cross-sectional view for explaining a method for determining the protruding angle of the convex portion.

[0097] First, in the laminated substrate 1, when viewed in a cross section along the thickness direction as shown in Fig. 3, the portion where the second resin material 11b bites into the interlayer connection conductor 30A is defined as the protrusion 12 (the same portion as the biting portion 11ba). Next, one end point of the protrusion 12 in the thickness direction is defined as a first point P1, the other end point of the protrusion 12 in the thickness direction is defined as a second point P2, and the vertex of the protrusion 12 in the surface direction is defined as a third point P3. Then, the angle θ formed by the line M1 connecting the first point P1 and the third point P3 and the line M2 connecting the second point P2 and the third point P3 is defined as the protrusion angle of the protrusion 12.

[0098] In the laminated substrate 1, when the protrusion angle θ of the convex portion 12 is 20° or more and 80° or less, the anchor effect of the convex portion 12 is further enhanced, making the interlayer connection conductor 30A even less likely to peel off from the resin layer 10A.

[0099] If the protrusion angle θ of the convex portion 12 is smaller than 20°, the tip of the convex portion 12 becomes too sharp, which tends to reduce the strength of the convex portion 12, and there is a risk that the anchor effect of the convex portion 12 will not be fully exerted.

[0100] If the protrusion angle θ of the convex portion 12 is greater than 80°, the tip of the convex portion 12 becomes too gentle, which tends to reduce the depth to which the convex portion 12 penetrates into the interlayer connecting conductor 30A, and there is a risk that the anchor effect of the convex portion 12 will not be fully exerted.

[0101] From the viewpoint of enhancing the anchor effect of the protrusions 12, the protrusion angle θ of the protrusions 12 is more preferably equal to or greater than 30° and equal to or less than 60°.

[0102] Of the pair of interfaces between the resin layer 10A and the interlayer connection conductor 30A, the proportion of the protrusions 12 at one interface is preferably 30% or more and 70% or less. Similarly, of the pair of interfaces between the resin layer 10A and the interlayer connection conductor 30A, the proportion of the protrusions 12 at the other interface is preferably 30% or more and 70% or less. From the above, the proportion of the protrusions 12 at each interface between the resin layer 10A and the interlayer connection conductor 30A is preferably 30% or more and 70% or less.

[0103] The proportion of the protrusions 12 at the interface between the resin layer 10A and the interlayer connection conductor 30A is determined as follows: First, by the method described above (see FIG. 3 ), the first point P1 and the second point P2 of all the protrusions 12, which are the portions of the second resin material 11b that have embedded into the interlayer connection conductor 30A at the interface (one interface or the other interface) between the resin layer 10A and the interlayer connection conductor 30A, are determined. Then, 100 × the total distance between the first point P1 and the second point P2 of all the protrusions 12 / the thickness of the resin layer 10A is calculated, and this is determined as the proportion of the protrusions 12 at the interface between the resin layer 10A and the interlayer connection conductor 30A.

[0104] The laminated substrate 1 is manufactured, for example, as follows.

[0105] <Step of Producing Resin Sheet with Conductor Layer> FIG. 4 is a cross-sectional view schematically showing a step of producing a resin sheet with a conductor layer in an example of the method for producing the laminated substrate according to the first embodiment of the present invention.

[0106] First, a resin composition containing the first resin material 11 a and the second resin material 11 b is prepared. For example, the first resin material 11 a and the second resin material 11 b are finely pulverized and then dispersed in a dispersion medium to prepare a paste or slurry-like resin composition. Examples of the dispersion medium include butanediol, water, ethanol, and a mixture containing at least two of these.

[0107] Next, a resin sheet 110A including the first resin material 11 a and the second resin material 11 b is produced using the resin composition by, for example, applying the resin composition and then drying it (to evaporate the dispersion medium), or by making the resin composition into paper and then drying it (to evaporate the dispersion medium).

[0108] In this specification, the term "sheet" is synonymous with "film," and the two are not distinguished by thickness.

[0109] Next, a conductor layer-equipped resin sheet 210A is fabricated as shown in Fig. 4, in which a conductor layer 20A is adjacent to a resin sheet 110A having a first main surface 110Aa and a second main surface 110Ab opposed to each other in the thickness direction, on the first main surface 110Aa side of the resin sheet 110A. In this case, for example, the conductor layer 20A is pressure-bonded to the first main surface 110Aa of the resin sheet 110A, thereby fabricating the conductor layer-equipped resin sheet 210A.

[0110] When the conductor layer 20A is pressure-bonded to the resin sheet 110A, for example, a heat press process is performed by heating and pressing the laminate of the resin sheet 110A and the conductor layer 20A in the thickness direction. The temperature during the heat press process is preferably equal to or higher than the melting point of the second resin material 11b and equal to or lower than the melting point of the first resin material 11a. When the heat press process is performed under the above temperature conditions, for example, the second resin material 11b melts and connects in the surface direction, making it easier to form a flat shape (layer) along the surface direction.

[0111] The conductor layer 20A may be patterned by etching after being pressure-bonded to the resin sheet 110A.

[0112] <Step of Forming Through Holes> FIG. 5 is a cross-sectional view that schematically shows a step of forming through holes in an example of the method for manufacturing the laminated substrate according to the first embodiment of the present invention.

[0113] As shown in Fig. 5, a through hole 131A is formed in the conductor layer-equipped resin sheet 210A, penetrating the resin sheet 110A in the thickness direction. In the example shown in Fig. 5, the through hole 131A is formed in the conductor layer-equipped resin sheet 210A so as to penetrate the resin sheet 110A in the thickness direction but not the conductor layer 20A in the thickness direction, and reach the conductor layer 20A. As a result, a part of the conductor layer 20A is exposed from the through hole 131A.

[0114] When forming the through holes 131A, for example, laser processing is performed by irradiating the conductor layer-equipped resin sheet 210A with laser light from the resin sheet 110A side. Taking advantage of the difference in processability between the first resin material 11a and the second resin material 11b, for example, by making the second resin material 11b a material with lower laser processability than the first resin material 11a, laser processing can be performed with lower energy, causing the second resin material 11b to protrude in the surface direction relative to the formed through holes 131A. Furthermore, by adjusting the energy used during laser processing, the number and protrusion angle of the portions of the second resin material 11b protruding in the surface direction relative to the through holes 131A (later protrusions 12) can be controlled.

[0115] <Step of Filling with Conductive Paste> FIG. 6 is a cross-sectional view schematically showing the step of filling with conductive paste in an example of the method for manufacturing the laminated substrate according to the first embodiment of the present invention.

[0116] As shown in FIG. 6, a conductive paste 132A is filled into the through holes 131A of a resin sheet 210A with a conductor layer.

[0117] Examples of methods for filling the conductive paste 132A include screen printing and vacuum filling.

[0118] The conductive paste 132A contains, for example, a metal and a resin.

[0119] Examples of metals contained in the conductive paste 132A include copper, tin, silver, etc. Among these, the conductive paste 132A preferably contains copper, and more preferably contains copper and tin.

[0120] The resin contained in the conductive paste 132A preferably includes at least one thermosetting resin selected from the group consisting of epoxy resin, phenolic resin, polyimide resin, silicone resin or modified resin thereof, and acrylic resin, or at least one thermoplastic resin selected from the group consisting of polyamide resin, polystyrene resin, polymethacrylic resin, polycarbonate resin, and cellulose-based resin.

[0121] The conductive paste 132A may further include a vehicle, a solvent, a thixotropic agent, an activator, and the like.

[0122] Examples of the vehicle include rosin-based resins made from rosin and derivatives thereof such as modified rosin, synthetic resins made from rosin and derivatives thereof such as modified rosin, and mixtures of these resins.

[0123] Examples of rosin-based resins made from rosin and derivatives thereof such as modified rosin include gum rosin, tall rosin, wood rosin, polymerized rosin, hydrogenated rosin, formylated rosin, rosin ester, rosin-modified maleic acid resin, rosin-modified phenolic resin, rosin-modified alkyd resin, and various other rosin derivatives.

[0124] Examples of synthetic resins made of rosin and derivatives thereof such as modified rosin include polyester resins, polyamide resins, phenoxy resins, and terpene resins.

[0125] Examples of solvents include alcohols, ketones, esters, ethers, aromatic solvents, and hydrocarbons. Specific examples of these solvents include benzyl alcohol, ethanol, isopropyl alcohol, butanol, diethylene glycol, ethylene glycol, glycerin, ethyl cellosolve, butyl cellosolve, ethyl acetate, butyl acetate, butyl benzoate, diethyl adipate, dodecane, tetradecene, α-terpineol, terpineol, 2-methyl-2,4-pentanediol, 2-ethylhexanediol, toluene, xylene, propylene glycol monophenyl ether, diethylene glycol monohexyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diisobutyl adipate, hexylene glycol, cyclohexanedimethanol, 2-terpinyloxyethanol, 2-dihydroterpinyloxyethanol, and mixtures thereof. Among these, terpineol, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, and diethylene glycol monoethyl ether are preferred.

[0126] Examples of thixotropic agents include hydrogenated castor oil, carnauba wax, amides, hydroxy fatty acids, dibenzylidene sorbitol, bis(p-methylbenzylidene)sorbitols, beeswax, stearic acid amide, hydroxystearic acid ethylene bisamide, etc. Furthermore, these thixotropic agents may contain, as necessary, fatty acids such as caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, hydroxy fatty acids such as 1,2-hydroxystearic acid, antioxidants, surfactants, amines, etc.

[0127] Examples of the activator include amine hydrohalides, organic halogen compounds, organic acids, organic amines, and polyhydric alcohols.

[0128] Examples of amine hydrohalides include diphenylguanidine hydrobromide, diphenylguanidine hydrochloride, cyclohexylamine hydrobromide, ethylamine hydrochloride, ethylamine hydrobromide, diethylaniline hydrobromide, diethylaniline hydrochloride, triethanolamine hydrobromide, and monoethanolamine hydrobromide.

[0129] Examples of the organic halogen compound include chlorinated paraffin, tetrabromoethane, dibromopropanol, 2,3-dibromo-1,4-butanediol, 2,3-dibromo-2-butene-1,4-diol, and tris(2,3-dibromopropyl)isocyanurate.

[0130] Examples of organic acids include malonic acid, fumaric acid, glycolic acid, citric acid, malic acid, succinic acid, phenylsuccinic acid, maleic acid, salicylic acid, anthranilic acid, glutaric acid, suberic acid, adipic acid, sebacic acid, stearic acid, abietic acid, benzoic acid, trimellitic acid, pyromellitic acid, and dodecanoic acid.

[0131] Examples of organic amines include monoethanolamine, diethanolamine, triethanolamine, tributylamine, aniline, and diethylaniline.

[0132] Examples of polyhydric alcohols include erythritol, pyrogallol, and ribitol.

[0133] <Step of Forming Interlayer Connection Conductors> FIG. 7 is a cross-sectional view that schematically shows a step of forming interlayer connection conductors in an example of the method for manufacturing the laminated substrate according to the first embodiment of the present invention.

[0134] As shown in Fig. 7, the conductor layer 20B is provided adjacent to the second main surface 110Ab of the resin sheet 110A and connected to the conductive paste 132A, thereby forming the structure 101 shown in Fig. 7. Then, the structure 101 is subjected to a hot press process by applying heat and pressure in the thickness direction to the structure 101. As a result, the resin sheet 110A, the conductor layer 20A, and the conductor layer 20B are pressure-bonded to each other, and the resin sheet 110A becomes the resin layer 10A. Furthermore, the conductive paste 132A solidifies during the hot press process to become the interlayer connection conductor 30A. In this manner, the interlayer connection conductor 30A is formed in the through hole 131A.

[0135] When forming the interlayer connection conductor 30A, instead of filling the through hole 131A with the conductive paste 132A, the inner wall of the through hole 131A may be plated with a metal such as copper, tin, or silver.

[0136] In this manner, the laminated substrate 1 shown in FIG. 1 is manufactured.

[0137] In the laminated substrate 1 manufactured in this manner, as described above, the second resin material 11b protrudes toward the through hole 131A in the planar direction, and therefore bites into the interlayer connection conductor 30A formed in the through hole 131A. Furthermore, in the laminated substrate 1, the first resin material 11a bites into the second resin material 11b that has bitten into the interlayer connection conductor 30A within the resin layer 10A.

[0138] FIG. 8 is an example of an enlarged cross-sectional image of the multilayer substrate according to the first embodiment of the present invention.

[0139] 8, it was confirmed that the second resin material 11b had bitten into the interlayer connection conductor 30A in the surface direction. Furthermore, it was confirmed that the first resin material 11a had bitten into the second resin material 11b that had bitten into the interlayer connection conductor 30A within the resin layer 10A.

[0140] [Embodiment 2] In the laminated substrate of embodiment 2 of the present invention, unlike the laminated substrate of embodiment 1 of the present invention, when viewed in a cross section along the thickness direction, the second resin material is present throughout at least one of a pair of interfaces between the resin layer and the interlayer connecting conductor.

[0141] FIG. 9 is a cross-sectional view schematically illustrating an example of a laminated substrate according to the second embodiment of the present invention.

[0142] In the laminated substrate 2 shown in Figure 9, when viewed in a cross section along the thickness direction, the second resin material 11b is present throughout at least one of the pair of interfaces between the resin layer 10A and the interlayer connecting conductor 30A.

[0143] In the example shown in FIG. 9, the second resin material 11b is present (aggregated) over the entire interface between the resin layer 10A and the interlayer connection conductor 30A.

[0144] The second resin material 11b may be present over the entirety of one of the pair of interfaces between the resin layer 10A and the interlayer connection conductor 30A.

[0145] In the laminate substrate 2, the second resin material 11b is present over the entirety of at least one of a pair of interfaces between the resin layer 10A and the interlayer connection conductor 30A. This, combined with the fact that the second resin material 11b is made of a thermoplastic resin and has a lower Young's modulus than the first resin material 11a, makes it possible for the second resin material 11b to function as a buffer material and sufficiently alleviate stress even if stress occurs at the interface between the resin layer 10A and the interlayer connection conductor 30A. As a result, in the laminate substrate 2, even if stress occurs at the interface between the resin layer 10A and the interlayer connection conductor 30A, cracks are sufficiently suppressed from occurring in the interlayer connection conductor 30A, and the connection reliability of the interlayer connection conductor 30A is therefore not likely to decrease.

[0146] From the viewpoint of achieving a configuration in which the connection reliability of the interlayer connection conductor 30A is less likely to decrease even when stress occurs at the interface between the resin layer 10A and the interlayer connection conductor 30A, as in the laminate substrate 1 (embodiment 1) and the laminate substrate 2 (embodiment 2), the abundance ratio of the second resin material 11b at one of the pair of interfaces between the resin layer 10A and the interlayer connection conductor 30A is preferably 30% or more and 100% or less. Similarly, the abundance ratio of the second resin material 11b at the other of the pair of interfaces between the resin layer 10A and the interlayer connection conductor 30A is preferably 30% or more and 100% or less. From the above, the abundance ratio of the second resin material 11b at each interface between the resin layer 10A and the interlayer connection conductor 30A is preferably 30% or more and 100% or less.

[0147] The abundance ratio of the second resin material 11b at the interface between the resin layer 10A and the interlayer connection conductor 30A is determined as follows: First, when viewing a cross section (e.g., see FIG. 2 ) along the thickness direction of the laminated substrate, all of the second resin material 11b that contacts the interlayer connection conductor 30A at the interface (one interface or the other interface) between the resin layer 10A and the interlayer connection conductor 30A is identified. Then, 100 × (the sum of the maximum dimensions in the thickness direction of the portions of all identified second resin material 11b that contact the interlayer connection conductor 30A) / (the thickness of the resin layer 10A) is calculated, and this is determined to be the abundance ratio of the second resin material 11b at the interface between the resin layer 10A and the interlayer connection conductor 30A.

[0148] [Embodiment 3] In the laminated substrate of embodiment 3 of the present invention, unlike the laminated substrates of embodiments 1 and 2 of the present invention, when viewed in a cross section along the thickness direction, the second resin material is longer than the interlayer connecting conductor on the same straight line extending in the surface direction.

[0149] FIG. 10 is a cross-sectional view schematically illustrating an example of a laminated substrate according to the third embodiment of the present invention.

[0150] 10, when viewed in a cross section along the thickness direction, the second resin material 11b is longer than the interlayer connection conductor 30A on the same straight line extending in the planar direction. In the example shown in FIG. 10, the second resin material 11b is longer than the interlayer connection conductor 30A on a straight line N1 extending in the planar direction.

[0151] In the laminate substrate 3, the second resin material 11b is longer than the interlayer connection conductor 30A on the same straight line extending in the surface direction, and therefore, even if stress occurs at the interface between the resin layer 10A and the interlayer connection conductor 30A, the second resin material 11b acts as a buffer material and tends to sufficiently relieve the stress, because the second resin material 11b is made of a thermoplastic resin and has a lower Young's modulus than the first resin material 11a. As a result, in the laminate substrate 3, even if stress occurs at the interface between the resin layer 10A and the interlayer connection conductor 30A, the occurrence of cracks in the interlayer connection conductor 30A is sufficiently suppressed, and the connection reliability of the interlayer connection conductor 30A is sufficiently unlikely to decrease.

[0152] [Embodiment 4] In the first to third embodiments, the laminated substrate of the present invention has one resin layer, but the laminated substrate of the present invention may have a plurality of resin layers.

[0153] FIG. 11 is a cross-sectional view schematically illustrating an example of a laminated substrate according to a fourth embodiment of the present invention.

[0154] The laminated substrate 4 shown in FIG. 11 has a resin layer 10A, a resin layer 10B, a resin layer 10C, a conductor layer 20A, a conductor layer 20B, a conductor layer 20C, a conductor layer 20D, and an interlayer connection conductor 30A.

[0155] As described above, the resin layer 10A has a first main surface 10Aa and a second main surface 10Ab that face each other in the thickness direction.

[0156] As described above, the resin layer 10A includes the first resin material 11a and the second resin material 11b.

[0157] The resin layer 10B has a first main surface 10Ba and a second main surface 10Bb that face each other in the thickness direction.

[0158] The first main surface 10Ba of the resin layer 10B faces the second main surface 10Ab of the resin layer 10A. In the example shown in Fig. 11, the first main surface 10Ba of the resin layer 10B contacts the second main surface 10Ab of the resin layer 10A except for the portion where the first main surface 10Ba contacts the conductor layer 20B.

[0159] The resin layer 10B preferably contains a first resin material 11a and a second resin material 11b.

[0160] The resin layer 10C has a first main surface 10Ca and a second main surface 10Cb that face each other in the thickness direction.

[0161] The second main surface 10Cb of the resin layer 10C faces the first main surface 10Aa of the resin layer 10A. In the example shown in Fig. 11, the second main surface 10Cb of the resin layer 10C is in contact with the first main surface 10Aa of the resin layer 10A except for the portion in contact with the conductor layer 20A.

[0162] The resin layer 10C preferably contains a first resin material 11a and a second resin material 11b.

[0163] The thicknesses of the resin layer 10A, the resin layer 10B, and the resin layer 10C may be the same as one another, may be different from one another, or may be partially different from one another.

[0164] As described above, the conductor layer 20A is adjacent to the first main surface 10Aa of the resin layer 10A. The conductor layer 20A is also adjacent to the second main surface 10Cb of the resin layer 10C. That is, the conductor layer 20A is located between the resin layer 10A and the resin layer 10C and is provided so as to be in contact with the first main surface 10Aa of the resin layer 10A and the second main surface 10Cb of the resin layer 10C. As such, no other layers, such as adhesive layers, are provided between the resin layer 10A and the conductor layer 20A, and between the resin layer 10C and the conductor layer 20A.

[0165] The conductor layer 20A is preferably provided across the interface between the resin layer 10A and the resin layer 10C. This causes the interface between the resin layer 10A and the conductor layer 20A and the interface between the resin layer 10C and the conductor layer 20A to be shifted in the thickness direction from the interface between the resin layer 10A and the resin layer 10C, thereby suppressing peeling at the interface between the resin layer 10A and the conductor layer 20A and the interface between the resin layer 10C and the conductor layer 20A.

[0166] 11 shows the interface between resin layer 10A and resin layer 10C, but in reality, this interface does not have to be clearly visible. When the interface between resin layer 10A and resin layer 10C is not clearly visible, in a cross section along the thickness direction as shown in FIG. 11, a plane that passes through the center in the thickness direction of the cross section of conductor layer 20A and extends along the surface direction is considered to be the interface between resin layer 10A and resin layer 10C.

[0167] As described above, the conductor layer 20B is adjacent to the second main surface 10Ab of the resin layer 10A. The conductor layer 20B is also adjacent to the first main surface 10Ba of the resin layer 10B. That is, the conductor layer 20B is located between the resin layer 10A and the resin layer 10B and is provided so as to be in contact with the second main surface 10Ab of the resin layer 10A and the first main surface 10Ba of the resin layer 10B. In this way, no other layer, such as an adhesive layer, is provided between the resin layer 10A and the conductor layer 20B, or between the resin layer 10B and the conductor layer 20B.

[0168] The conductor layer 20B is preferably provided across the interface between the resin layer 10A and the resin layer 10B. This allows the interface between the resin layer 10A and the conductor layer 20B and the interface between the resin layer 10B and the conductor layer 20B to be shifted in the thickness direction from the interface between the resin layer 10A and the resin layer 10B, thereby suppressing peeling at the interface between the resin layer 10A and the conductor layer 20B and the interface between the resin layer 10B and the conductor layer 20B.

[0169] 11 shows the interface between resin layer 10A and resin layer 10B, but in reality, this interface does not have to be clearly visible. When the interface between resin layer 10A and resin layer 10B is not clearly visible, in a cross section along the thickness direction as shown in FIG. 11, a plane that passes through the center in the thickness direction of the cross section of conductor layer 20B and extends along the surface direction is considered to be the interface between resin layer 10A and resin layer 10B.

[0170] The conductor layer 20C is adjacent to the second main surface 10Bb side of the resin layer 10B. As described above, no other layer such as an adhesive layer is provided between the resin layer 10B and the conductor layer 20C.

[0171] The conductor layer 20C may be in the form of a surface extending over the entire second main surface 10Bb of the resin layer 10B, or may be in the form of a pattern patterned into wiring or the like on a portion of the second main surface 10Bb of the resin layer 10B.

[0172] The conductor layer 20D is adjacent to the first main surface 10Ca side of the resin layer 10C. As described above, no other layer such as an adhesive layer is provided between the resin layer 10C and the conductor layer 20D.

[0173] The conductor layer 20D may be in the form of a surface extending over the entire first main surface 10Ca of the resin layer 10C, or may be in the form of a pattern patterned into wiring or the like on a portion of the first main surface 10Ca of the resin layer 10C.

[0174] The constituent materials of the conductor layer 20A, the conductor layer 20B, the conductor layer 20C, and the conductor layer 20D may be the same as or different from one another, or may be partially different from one another.

[0175] The thicknesses of the conductor layer 20A, the conductor layer 20B, the conductor layer 20C, and the conductor layer 20D may be the same as one another, may be different from one another, or may be partially different.

[0176] As described above, the interlayer connection conductor 30A penetrates the resin layer 10A in the thickness direction but does not penetrate the conductor layers 20A and 20B in the thickness direction, and is connected to the conductor layers 20A and 20B. In other words, the conductor layers 20A and 20B are electrically connected via the interlayer connection conductor 30A.

[0177] The laminated substrate 4 is used as, for example, a circuit board.

[0178] When the laminated substrate 4 is used as a circuit board, the laminated substrate 4 may have a conductor layer 20A as a signal line for transmitting a signal to form a transmission line. Note that the laminated substrate 4 may have a conductor layer 20B as the signal line instead of the conductor layer 20A.

[0179] When the laminated substrate 4 has a conductor layer 20A or a conductor layer 20B as a signal line for transmitting a signal and forms a transmission line, if the relative dielectric constant of the second resin material 11b is lower than the relative dielectric constant of the first resin material 11a as described above, and if a large amount of the second resin material 11b is present in the vicinity of the signal line, the high-frequency characteristics of the laminated substrate 4 will be excellent.

[0180] When the laminated substrate 4 has the conductor layer 20A or the conductor layer 20B as a signal line for transmitting a signal and forms a transmission line, if the dielectric tangent of the second resin material 11b is lower than the dielectric tangent of the first resin material 11a as described above, and if a large amount of the second resin material 11b is present in the vicinity of the signal line, the laminated substrate 4 will have excellent transmission loss characteristics.

[0181] When the laminate substrate 4 is used as a circuit board, the laminate substrate 4 may have the conductor layer 20A or conductor layer 20B as a signal line for transmitting signals, and the conductor layer 20C and the conductor layer 20D as ground electrodes. In this case, the laminate substrate 4 forms a stripline-type transmission line. In such a configuration, the conductor layer 20C and the conductor layer 20D may be electrically connected via an interlayer connection conductor (not shown) that penetrates the resin layer 10A, the resin layer 10B, and the resin layer 10C in the thickness direction. Note that the conductor layer 20C and the conductor layer 20D do not have to be electrically connected.

[0182] When the laminated substrate of the present invention constitutes a transmission line, the laminated substrate of the present invention may constitute, for example, a microstrip transmission line, a coplanar transmission line, or the like, in addition to the stripline transmission line described above.

[0183] [Embodiment 5] In embodiments 1 to 4, in the laminated substrate of the present invention, the interlayer connection conductor penetrates the resin layer in the thickness direction but does not penetrate the conductor layer in the thickness direction, but the interlayer connection conductor may also penetrate the resin layer and the conductor layer in the thickness direction.

[0184] FIG. 12 is a cross-sectional view schematically illustrating an example of a laminated substrate according to a fifth embodiment of the present invention.

[0185] In the laminated substrate 5 shown in FIG. 12, the interlayer connection conductor 30B penetrates the resin layer 10A and the conductor layer 20B in the thickness direction and is connected to the conductor layer 20B.

[0186] The interlayer connection conductor 30B is formed, for example, by applying a conductive paste to a through hole that penetrates the resin layer 10A and the conductor layer 20B in the thickness direction, followed by heat treatment, plating the inner wall, or sputtering the inner wall.

[0187] The laminated substrate of the present invention is not limited to the above-described embodiment, and various applications and modifications can be made within the scope of the present invention with respect to the configuration of the laminated substrate, manufacturing conditions, and the like.

[0188] In the laminated substrate of the present invention, when multiple second resin materials are present within the resin layer, if there is a second resin material that has penetrated into the interlayer connecting conductor, there may also be a second resin material that has not penetrated into the interlayer connecting conductor.

[0189] In the laminated substrate of the present invention, as long as the second resin material is present and has penetrated into the interlayer connection conductors, the first resin material may also be present and have penetrated into the interlayer connection conductors.

[0190] In the laminated substrate of the present invention, the number of resin layers is not particularly limited as long as it is one or more.

[0191] In the laminated substrate of the present invention, the number of conductor layers is not particularly limited as long as it is one or more.

[0192] In the laminated substrate of the present invention, the number of interlayer connection conductors is not particularly limited as long as it is one or more.

[0193] EXAMPLES Hereinafter, examples will be given that more specifically disclose the laminated substrate of the present invention, but the present invention is not limited to the following examples.

[0194] [Examples 1 to 7] The laminated substrates of Examples 1 to 7 were manufactured by the laminated substrate manufacturing method of Embodiment 1. In this case, the materials shown in Table 1 were used as the first resin material and the second resin material. In addition, in the <step of forming through holes>, the energy during laser processing was adjusted to change the number of protrusions, which are the portions of the second resin material that bite into the interlayer connection conductors.

[0195] [Comparative Example 1] The laminated substrate of Comparative Example 1 was manufactured in the same manner as in Examples 1 to 7, except that the energy during laser processing in the <Process for forming through holes> was increased to prevent the formation of a convex portion, which is the portion where the second resin material has embedded in the interlayer connecting conductor, in the laminated substrate obtained later.

[0196] [Evaluation] The following evaluations were carried out on the laminated substrates of Examples 1 to 7 and Comparative Example 1. The evaluation results are shown in Table 1.

[0197] <Number of convex portions> The number of convex portions, which are portions where the second resin material has embedded into the interlayer connection conductor, was counted as the number of portions determined to be convex portions (embedding portions) by the method described above (see FIG. 2). At this time, for a pair of interfaces between the resin layer and the interlayer connection conductor, the number of convex portions at one interface, the number of convex portions at the other interface, and the total number of convex portions at both interfaces were counted.

[0198] In each example of the laminated substrate, the protrusion angle of the convex portion was the same.

[0199] <Connection Reliability> The connection reliability of the interlayer connection conductors was evaluated as follows. First, the resistivity R1 of the interlayer connection conductors was measured for the laminated substrate. Next, a hot oil test (thermal shock test) was performed, in which the laminated substrate was immersed in oil at 260°C for 10 seconds and then in oil at 20°C for 20 seconds, with one cycle consisting of 200 cycles of immersion. After the hot oil test, the resistivity R2 of the interlayer connection conductors was measured for the laminated substrate. The change in resistivity (unit: %) of the interlayer connection conductors before and after the hot oil test was calculated as 100 × (R2 - R1) / R1. The criteria for judging the connection reliability of the interlayer connection conductors were as follows: ◎ (Excellent): The change in resistivity was 5% or less. ○ (Good): The change in resistivity was more than 5% but not more than 10%. △ (Fair): The change in resistivity was more than 10% but not more than 20%. × (Unacceptable): The change in resistivity was more than 20%.

[0200]

[0201] As shown in Table 1, the laminate substrates of Examples 1 to 7, which had one or more convex portions, had superior connection reliability of the interlayer connection conductors compared to the laminate substrate of Comparative Example 1, which had no convex portions. In other words, it is considered that the interlayer connection conductors were less likely to peel off from the resin layer in the laminate substrates of Examples 1 to 7.

[0202] Among the laminated substrates of Examples 1 to 7, when comparing the laminated substrates of Examples 1 to 4 in which the types of the first resin material and the second resin material are the same, the laminated substrates of Examples 2 and 3 in which the total number of convex portions at both interfaces is 3 or more and 20 or less had superior connection reliability of the interlayer connecting conductors compared to the laminated substrates of Examples 1 and 4 in which the total number of convex portions at both interfaces is less than 3 or more than 20.

[0203] Similarly, when comparing the laminated substrates of Examples 1 to 4, which have the same types of first resin material and second resin material among the laminated substrates of Examples 1 to 7, the laminated substrates of Examples 2 and 3, which have two or more and ten or less convex portions at one interface (the other interface), had superior connection reliability of the interlayer connecting conductors compared to the laminated substrates of Examples 1 and 4, which have fewer than two or more than ten convex portions at one interface (the other interface).

[0204] Among the laminated substrates of Examples 1 to 7, when comparing the laminated substrates of Examples 2 and 5 to 7 which have the same number of convex portions, the laminated substrate of Example 2 in which the second resin material is polyphenylene ether and the laminated substrate of Example 5 in which the second resin material is perfluoroalkoxyalkane had superior connection reliability of the interlayer connecting conductors compared to the laminated substrates of Examples 6 and 7 in which the second resin material is other than polyphenylene ether and perfluoroalkoxyalkane.

[0205] [Examples 8 to 15] The laminated substrates of Examples 8 to 15 were manufactured by the laminated substrate manufacturing method of Embodiment 1. In this case, the materials shown in Table 2 were used as the first resin material and the second resin material. In addition, in the <step of forming a through hole>, the protruding angle of the convex portion, which is the portion of the second resin material that bites into the interlayer connection conductor, was changed by adjusting the energy during laser processing.

[0206] [Evaluation] The following evaluations were carried out on the laminated substrates of Examples 8 to 15. The evaluation results are shown in Table 2.

[0207] <Protrusion Angle of Convex Portion> The protrusion angle of the convex portion, which is the portion where the second resin material bites into the interlayer connection conductor, was measured by the method described above (see FIG. 3).

[0208] The number of protrusions was the same in each example of the laminated substrate.

[0209] <Connection Reliability> The connection reliability of the interlayer connection conductor was evaluated by the method described above.

[0210]

[0211] As shown in Table 2, the connection reliability of the interlayer connection conductors was excellent in the laminated boards of Examples 8 to 15. In other words, it is considered that in the laminated boards of Examples 8 to 15, the interlayer connection conductors were less likely to peel off from the resin layer.

[0212] Among the laminate substrates of Examples 8 to 15, when comparing the laminate substrates of Examples 8 to 12 in which the types of the first resin material and the second resin material were the same, the laminate substrates of Examples 9 to 11 in which the protruding angle of the convex portion was 20° or more and 80° or less had superior connection reliability of the interlayer connection conductor compared to the laminate substrates of Examples 8 and 12 in which the protruding angle of the convex portion was less than 20° or more than 80°. Furthermore, when comparing the laminate substrates of Examples 8 to 12, the laminate substrate of Example 10 in which the protruding angle of the convex portion was 30° or more and 60° or less had superior connection reliability of the interlayer connection conductor compared to the laminate substrates of Examples 8, 9, 11, and 12 in which the protruding angle of the convex portion was less than 30° or more than 60°.

[0213] Among the laminated substrates of Examples 8 to 15, when comparing the laminated substrates of Examples 10 and 13 to 15, which have the same protruding angle of the convex portion, the laminated substrate of Example 10, in which the second resin material is polyphenylene ether, and the laminated substrate of Example 13, in which the second resin material is perfluoroalkoxyalkane, had superior connection reliability of the interlayer connecting conductor compared to the laminated substrates of Examples 14 and 15, in which the second resin material is other than polyphenylene ether and perfluoroalkoxyalkane.

[0214] The present specification discloses the following:

[0215] <1> A laminated substrate comprising: a resin layer having a pair of main surfaces opposing each other in a thickness direction; a conductor layer adjacent to at least one of the main surfaces of the resin layer; and an interlayer connection conductor connected to the conductor layer while penetrating the resin layer in the thickness direction, wherein the resin layer contains a first resin material and a second resin material made of a thermoplastic resin, wherein the Young's modulus of the second resin material is lower than the Young's modulus of the first resin material, the second resin material bites into the interlayer connection conductor in a plane direction perpendicular to the thickness direction, and the first resin material bites into the second resin material that bites into the interlayer connection conductor within the resin layer.

[0216] <2> The laminated substrate described in <1>, wherein, when viewed in a cross section along the thickness direction, the portions where the second resin material has embedded in the interlayer connection conductor are defined as convex portions, and the total number of the convex portions at a pair of interfaces between the resin layer and the interlayer connection conductor is 3 or more and 20 or less.

[0217] <3> The laminated substrate according to <2>, wherein the number of the protrusions at one of the interfaces is 2 or more and 10 or less.

[0218] <4> The laminated substrate according to any one of <1> to <3>, wherein, when viewed in cross section along the thickness direction, a portion where the second resin material has bitten into the interlayer connection conductor is defined as a convex portion, one end point of the convex portion in the thickness direction is defined as a first point, the other end point of the convex portion in the thickness direction is defined as a second point, and the vertex of the convex portion in the surface direction is defined as a third point, an angle formed by a line connecting the first point and the third point and a line connecting the second point and the third point is 20° or more and 80° or less.

[0219] <5> The laminated substrate according to any one of <1> to <4>, wherein, when viewed in a cross section along the thickness direction, the second resin material is present over the entirety of at least one of a pair of interfaces between the resin layer and the interlayer connection conductor.

[0220] <6> The laminated substrate according to any one of <1> to <5>, wherein, when viewed in a cross section along the thickness direction, the second resin material is longer than the interlayer connection conductor on the same straight line extending in the surface direction.

[0221] <7> The laminated substrate according to any one of <1> to <6>, wherein the first resin material is made of a thermoplastic resin.

[0222] <8> The laminated substrate according to <7>, wherein the first resin material is made of a liquid crystal polymer.

[0223] <9> The laminated substrate according to any one of <1> to <8>, wherein the second resin material is made of a perfluoroalkoxyalkane.

[0224] <10> The laminated substrate according to any one of <1> to <8>, wherein the second resin material is made of polyphenylene ether.

[0225] <11> The laminated substrate according to any one of <1> to <10>, wherein the second resin material has a flat shape.

[0226] <12> The laminated substrate according to any one of <1> to <11>, which has the conductor layer as a signal line for transmitting a signal, and forms a transmission line.

[0227] 1, 2, 3, 4, 5 Laminated substrate 10A, 10B, 10C Resin layer 10Aa, 10Ba, 10Ca, 110Aa First main surface 10Ab, 10Bb, 10Cb, 110Ab Second main surface 11a First resin material 11b Second resin material 11ba Biting portion 11bb Non-biting portion 12 Convex portion 20A, 20B, 20C, 20D Conductive layer 30A, 30B Interlayer connection conductor 101 Structure 110A Resin sheet 131A Through hole 132A Conductive paste 210A Resin sheet with conductor layer E1, E2 End point F1 Midpoint G1 Distance L1, L2, M1, M2, N1 Straight line P1 First point P2 Second point P3 Third point θ: Projection angle of the convex part

Claims

1. A laminated substrate comprising: a resin layer having a pair of main surfaces opposing each other in a thickness direction; a conductor layer adjacent to at least one of the main surfaces of the resin layer; and an interlayer connection conductor connected to the conductor layer while penetrating the resin layer in the thickness direction, wherein the resin layer comprises a first resin material and a second resin material made of a thermoplastic resin, wherein the Young's modulus of the second resin material is lower than the Young's modulus of the first resin material, the second resin material bites into the interlayer connection conductor in a surface direction perpendicular to the thickness direction, and the first resin material bites into the second resin material which bites into the interlayer connection conductor within the resin layer.

2. The laminated substrate according to claim 1, wherein, when viewed in a cross section along the thickness direction, the portions where the second resin material has embedded into the interlayer connection conductor are defined as convex portions, and the total number of said convex portions at a pair of interfaces between the resin layer and the interlayer connection conductor is 3 or more and 20 or less.

3. The laminated substrate according to claim 2, wherein the number of said protrusions at one of said interfaces is 2 or more and 10 or less.

4. A laminated substrate as described in any one of claims 1 to 3, wherein, when viewed in a cross section along the thickness direction, a portion where the second resin material bites into the interlayer connection conductor is defined as a convex portion, one end point of the convex portion in the thickness direction is defined as a first point, the other end point of the convex portion in the thickness direction is defined as a second point, and the apex of the convex portion in the surface direction is defined as a third point, an angle formed by a line connecting the first point and the third point and a line connecting the second point and the third point is 20° or more and 80° or less.

5. A laminated substrate as described in any one of claims 1 to 4, wherein, when viewed in a cross section along the thickness direction, the second resin material is present across the entirety of at least one of a pair of interfaces between the resin layer and the interlayer connection conductor.

6. A laminated substrate according to any one of claims 1 to 5, wherein, when viewed in a cross section along the thickness direction, the second resin material is longer than the interlayer connection conductor on the same straight line extending in the surface direction.

7. The laminated substrate according to any one of claims 1 to 6, wherein the first resin material is made of a thermoplastic resin.

8. The laminated substrate according to claim 7, wherein the first resin material is made of a liquid crystal polymer.

9. The laminated substrate according to any one of claims 1 to 8, wherein the second resin material is made of perfluoroalkoxyalkane.

10. The laminated board according to any one of claims 1 to 8, wherein the second resin material is made of polyphenylene ether.

11. The laminated substrate according to any one of claims 1 to 10, wherein the second resin material is flat.

12. The laminated board according to any one of claims 1 to 11, comprising the conductor layer as a signal line for transmitting a signal, forming a transmission line.

Images