Multilayer substrate and method for manufacturing multilayer substrate

Abstract

According to the present invention, a first insulator layer has a positive main surface and a negative main surface positioned on a negative side of a Z-axis relative to the positive main surface. A first conductor layer and a second conductor layer are positioned on the positive main surface of the first insulator layer. A first columnar conductor and a second columnar conductor are provided in a through-hole that passes through the first insulator layer along the Z axis. An end of the first columnar conductor on the positive side of the Z-axis is in contact with the first conductor layer. An end of the first columnar conductor on the negative side of the Z-axis is connected to a first conductor positioned on the negative side of the Z-axis of the first columnar conductor. An end of the second columnar conductor on the positive side of the Z-axis is in contact with the second conductor layer. An end of the second columnar conductor on the negative side of the Z-axis is not in contact with any of the conductors. The material of the first columnar conductor is the same as the material of the second columnar conductor.

Description

Multilayer substrate and method for manufacturing the same

[0001] The present invention relates to a multilayer substrate having a structure in which a plurality of insulating layers are stacked.

[0002] As a conventional invention relating to a multilayer board, for example, a method for manufacturing a wired circuit board described in Patent Document 1 is known. In this method for manufacturing a wired circuit board, a seed film and wiring are formed on a base insulating layer. The seed film and wiring are made of conductors. Therefore, the resistance of a current path including the seed film and wiring is reduced.

[0003] Japanese Patent Application Laid-Open No. 2022-027927

[0004] As described above, in the field of the wired circuit board described in Patent Document 1, there is a demand for lower resistance in the current path including the seed film and the wiring.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a multilayer substrate and a method for manufacturing the multilayer substrate that can reduce the resistance of the current path.

[0006] A multilayer substrate according to one embodiment of the present invention includes at least a laminate, a first conductor layer, a second conductor layer, a first columnar conductor, a second columnar conductor, and a connecting conductor, wherein the laminate has a structure in which a plurality of insulator layers including a first insulator layer are stacked along the Z axis, the first insulator layer has a positive main surface and a negative main surface located on the negative side of the Z axis from the positive main surface, the first conductor layer and the second conductor layer are located on the positive main surface of the first insulator layer, the first columnar conductor and the second columnar conductor are provided inside a through hole penetrating the first insulator layer along the Z axis, an end of the first columnar conductor on the positive side of the Z axis contacts the first conductor layer, the connecting conductor is a conductor that electrically connects conductors in the stacking direction, and the end of the first columnar conductor on the negative side of the Z axis is connected to the columnar conductor or a conductor layer via the connecting conductor, The positive end of the second columnar conductor along the Z axis is in contact with the second conductor layer, the negative end of the second columnar conductor along the Z axis is not in contact with any conductor, and the material of the first columnar conductor and the material of the second columnar conductor are the same material.

[0007] A method for manufacturing a multilayer substrate according to one embodiment of the present invention includes a first preparation step, a through hole forming step, a conductor layer forming step, a columnar conductor forming step, a second preparation step, and a crimping step, wherein the first preparation step includes preparing a first insulator layer having a positive main surface and a negative main surface located on the negative side of the positive main surface along the Z axis, the first insulator layer being provided with metal foil covering the positive main surface, the through hole forming step including forming a first through hole and a second through hole penetrating along the Z axis in the first insulator layer, the conductor layer forming step including processing the metal foil to form a first conductor layer and a second conductor layer, the columnar conductor forming step including forming a first columnar conductor and a second columnar conductor in the first through hole and the second through hole, respectively, and the second preparation step including preparing a second insulator layer provided with a connecting conductor, In the crimping process, a plurality of insulator layers including the first insulator layer and the second insulator layer are stacked and crimped so that the first insulator layer is located on the positive side of the Z axis relative to the second insulator layer, the end of the first columnar conductor on the positive side of the Z axis is in contact with the first conductor layer, the end of the second columnar conductor on the positive side of the Z axis is in contact with the second conductor layer, and the end of the first columnar conductor on the negative side of the Z axis is connected to the connecting conductor.

[0008] According to the multilayer substrate and the method for manufacturing the multilayer substrate of the present invention, it is possible to reduce the resistance of the current path.

[0009] FIG. 1 is an exploded perspective view of a multilayer substrate 10. FIG. 2 is a cross-sectional view of the multilayer substrate 10. FIG. 3 is a cross-sectional view of the multilayer substrate 10 during manufacturing. FIG. 4 is a cross-sectional view of the multilayer substrate 10 during manufacturing. FIG. 5 is a cross-sectional view of the multilayer substrate 10 during manufacturing. FIG. 6 is a cross-sectional view of the multilayer substrate 10 during manufacturing. FIG. 7 is a cross-sectional view of the multilayer substrate 10 during manufacturing. FIG. 8 is a cross-sectional view of the multilayer substrate 10 during manufacturing. FIG. 9 is a cross-sectional view of the multilayer substrate 10 during manufacturing. FIG. 10 is a cross-sectional view of the multilayer substrate 10 during manufacturing. FIG. 11 is a cross-sectional view of a multilayer substrate 10a. FIG. 12 is a cross-sectional view of a multilayer substrate 10b. FIG. 13 is a top view of an insulator layer 16c of a multilayer substrate 10c. FIG. 14 is a top view of an insulator layer 16c of a multilayer substrate 10d. FIG. 15 is a rear view of the multilayer substrate 10d during use. FIG. 16 is a top view of an insulator layer 16c of a multilayer substrate 10e.

[0010] (Embodiment) [Structure of Multilayer Substrate] The structure of a multilayer substrate 10 according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of the multilayer substrate 10. FIG. 2 is a cross-sectional view of the multilayer substrate 10. FIG. 2 shows a cross section taken along line A-A in FIG. 1. Note that in FIG. 1, reference symbols are assigned only to representative columnar conductors v1a to v1d, v2a to v2d, and v3a to v3d among the multiple columnar conductors v1a to v1d, v2a to v2d, and v3a to v3d.

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

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

[0013] First, the structure of a multilayer substrate 10 will be described with reference to FIG. 1 . The multilayer substrate 10 transmits high-frequency signals. The multilayer substrate 10 is used to electrically connect two circuits in electronic devices such as smartphones. As shown in FIG. 1 , the multilayer substrate 10 includes a laminate 12, protective layers 18a and 18b, a signal conductor layer 20a, a power supply conductor layer 20b, a first ground conductor layer 22, a second ground conductor layer 24, ground conductor layers 26a, 26b, 28a, 28b, 30a, and 30b, a plurality of columnar conductors v1a to v1d, a plurality of columnar conductors v2a to v2d, a plurality of columnar conductors v3a to v3d, a columnar conductor v10, and connecting conductors v11d, v12d, and v13d. The connecting conductors v11d, v12d, and v13d are made of different materials from the columnar conductors v1c to v3c and v1d to v3d.

[0014] The laminate 12 has a plate shape. Therefore, the laminate 12 has an upper main surface (positive main surface) and a lower main surface (negative main surface) located below the upper main surface (positive main surface) (on the negative side of the Z axis). The upper and lower main surfaces of the laminate 12 have a rectangular shape with long sides extending along the left-right axis. Therefore, the length of the laminate 12 in the left-right direction is longer than the length of the laminate 12 in the front-rear direction. The laminate 12 is flexible.

[0015] As shown in FIG. 1, the laminate 12 has a structure in which insulator layers 16a to 16d, including insulator layer 16c (first insulator layer), are stacked along a vertical axis (Z-axis). The insulator layers 16a to 16d are arranged in this order from top to bottom. The insulator layers 16a to 16d each have an upper main surface (positive main surface) and a lower main surface (negative main surface) located below the upper main surface (positive main surface) (on the negative side of the Z-axis). The material of the insulator layers 16a to 16d is, for example, a thermoplastic resin. The thermoplastic resin is, for example, a liquid crystal polymer. The insulator layers 16a to 16d are fused together so that adjacent layers are vertically adjacent to each other.

[0016] A high-frequency signal is transmitted through the signal conductor layer 20a. As shown in FIG. 1 , the signal conductor layer 20a (third conductor layer) is located on the upper main surface (front main surface) of the insulator layer 16c (first insulator layer). When viewed downward, the signal conductor layer 20a has a linear shape extending along the left-right axis. The signal conductor layer 20a has an upper main surface and a lower main surface located below the upper main surface. The surface roughness of the lower main surface of the signal conductor layer 20a is greater than the surface roughness of the upper main surface of the signal conductor layer 20a.

[0017] A power supply potential is connected to the power supply conductor layer 20b. As shown in FIG. 1, the power supply conductor layer 20b (second conductor layer) is located on the upper main surface (positive main surface) of the insulator layer 16c (first insulator layer). When viewed downward (negative direction of the Z axis), the power supply conductor layer 20b has a linear shape extending along the left-right axis. Therefore, the power supply conductor layer 20b is parallel to the signal conductor layer 20a. In this embodiment, the power supply conductor layer 20b is located behind the signal conductor layer 20a. As shown in FIG. 2, the line width Wb of the power supply conductor layer 20b is larger than the line width Wa of the signal conductor layer 20a. The power supply conductor layer 20b (second conductor layer) has an upper main surface (positive main surface) and a lower main surface (negative main surface) located below the upper main surface (positive main surface) (negative side of the Z axis). The surface roughness of the lower main surface (negative main surface) of the power supply conductor layer 20b is greater than the surface roughness of the upper main surface (positive main surface) of the power supply conductor layer 20b.

[0018] As shown in FIG. 1 , the first ground conductor layer 22 is provided on the laminate 12. The first ground conductor layer 22 is located above the signal conductor layer 20a and the power conductor layer 20b and overlaps the signal conductor layer 20a and the power conductor layer 20b when viewed downward. In this embodiment, the first ground conductor layer 22 is located on the upper main surface of the insulator layer 16a. The first ground conductor layer 22 covers substantially the entire upper main surface of the insulator layer 16a. The first ground conductor layer 22 has an upper main surface and a lower main surface located below the upper main surface. The surface roughness of the lower main surface of the first ground conductor layer 22 is greater than the surface roughness of the upper main surface of the first ground conductor layer 22. A ground potential is connected to the first ground conductor layer 22.

[0019] As shown in FIG. 1 , the second ground conductor layer 24 is provided on the laminate 12. The second ground conductor layer 24 is located below the signal conductor layer 20a and the power supply conductor layer 20b and overlaps the signal conductor layer 20a and the power supply conductor layer 20b when viewed from below. In this embodiment, the second ground conductor layer 24 is located on the lower main surface of the insulator layer 16d. The second ground conductor layer 24 also covers substantially the entire lower main surface of the insulator layer 16d. The second ground conductor layer 24 has an upper main surface and a lower main surface located below the upper main surface. The surface roughness of the upper main surface of the second ground conductor layer 24 is greater than the surface roughness of the lower main surface of the second ground conductor layer 24. A ground potential is connected to the second ground conductor layer 24. The signal conductor layer 20a, the first ground conductor layer 22, and the second ground conductor layer 24 as described above have a stripline structure.

[0020] As shown in FIG. 1 , the ground conductor layers 26a, 28a, and 30a are provided on the laminate 12. When viewed from below, the ground conductor layers 26a, 28a, and 30a do not overlap the signal conductor layer 20a and the power conductor layer 20b. In this embodiment, the ground conductor layers 26a, 28a, and 30a are located on the upper main surface of the insulator layer 16b. When viewed from below, the ground conductor layers 26a, 28a, and 30a have linear shapes extending in the left-right direction. When viewed from below, the ground conductor layer 26a is located in front of the signal conductor layer 20a. When viewed from below, the ground conductor layer 28a is located behind the signal conductor layer 20a and in front of the power conductor layer 20b. When viewed from below, the ground conductor layer 30a is located behind the power conductor layer 20b. The ground conductor layers 26a, 28a, and 30a each have an upper main surface and a lower main surface located below the upper main surface. The surface roughness of the lower principal surfaces of the ground conductor layers 26a, 28a, and 30a is greater than the surface roughness of the upper principal surfaces of the ground conductor layers 26a, 28a, and 30a.

[0021] As shown in FIG. 1 , the ground conductor layers 26b, 28b, and 30b are provided on the laminate 12. When viewed from below, the ground conductor layers 26b, 28b, and 30b do not overlap the signal conductor layer 20a and the power conductor layer 20b. In this embodiment, the ground conductor layers 26b, 28b, and 30b (first conductor layers) are located on the upper main surface of the insulator layer 16c. When viewed from below, the ground conductor layers 26b, 28b, and 30b have linear shapes extending in the left-right direction. When viewed from below, the ground conductor layer 26b is located in front of the signal conductor layer 20a. When viewed from below, the ground conductor layer 28b is located behind the signal conductor layer 20a and in front of the power conductor layer 20b. When viewed from below, the ground conductor layer 30b is located behind the power conductor layer 20b. The ground conductor layers 26b, 28b, and 30b each have an upper main surface and a lower main surface located below the upper main surface. The surface roughness of the lower main surface of the ground conductor layers 26b, 28b, and 30b is greater than the surface roughness of the upper main surface of the ground conductor layers 26b, 28b, and 30b.

[0022] As shown in FIG. 2 , the plurality of columnar conductors v1a, v2a, and v3a penetrate the insulator layer 16a along the vertical axis. The columnar conductors v1a, v2a, and v3a have sections in which the thicknesses of the columnar conductors v1a, v2a, and v3a decrease upward. The upper ends of the columnar conductors v1a contact the first ground conductor layer 22. The lower ends of the columnar conductors v1a contact the ground conductor layer 26a. The columnar conductors v1a are aligned in a line along the horizontal axis. The upper ends of the columnar conductors v2a contact the first ground conductor layer 22. The lower ends of the columnar conductors v2a contact the ground conductor layer 28a. The columnar conductors v2a are aligned in a line along the horizontal axis. The upper ends of the columnar conductors v3a contact the first ground conductor layer 22. The lower ends of the plurality of columnar conductors v3a are in contact with the ground conductor layer 30a and are aligned in a line along the left-right axis.

[0023] The multiple columnar conductors v1b, v2b, and v3b penetrate the insulator layer 16b along the up-down axis. The multiple columnar conductors v1b, v2b, and v3b have sections in which the thickness of the multiple columnar conductors v1b, v2b, and v3b decreases upward. The upper ends of the multiple columnar conductors v1b contact the ground conductor layer 26a. The lower ends of the multiple columnar conductors v1b contact the ground conductor layer 26b. The multiple columnar conductors v1b are aligned in a line along the left-right axis. The upper ends of the multiple columnar conductors v2b contact the ground conductor layer 28a. The lower ends of the multiple columnar conductors v2b contact the ground conductor layer 28b. The multiple columnar conductors v2b are aligned in a line along the left-right axis. The upper ends of the multiple columnar conductors v3b contact the ground conductor layer 30a. The lower ends of the plurality of columnar conductors v3b are in contact with the ground conductor layer 30b. The plurality of columnar conductors v3b are aligned in a line along the left-right axis.

[0024] The plurality of columnar conductors v1c, v2c, and v3c (first columnar conductors) are disposed in through holes that penetrate the insulator layer 16c (first insulator layer) along the vertical axis. In this embodiment, the plurality of columnar conductors v1c, v2c, and v3c (first columnar conductors) penetrate the insulator layer 16c (first insulator layer) along the vertical axis. The plurality of columnar conductors v1c, v2c, and v3c (first columnar conductors) have sections in which the thickness of the plurality of columnar conductors v1c, v2c, and v3c decreases upward (in the positive direction of the Z axis). The upper ends of the plurality of columnar conductors v1c contact the ground conductor layer 26b. The plurality of columnar conductors v1c are aligned in a line along the horizontal axis. The upper ends of the plurality of columnar conductors v2c (first columnar conductors) contact the ground conductor layer 28b. The columnar conductors v2c are aligned in a line along the left-right axis. The upper ends of the columnar conductors v3c are in contact with the ground conductor layer 30b. The columnar conductors v3c are aligned in a line along the left-right axis.

[0025] The columnar conductors v1d, v2d, and v3d are disposed in through holes that penetrate the insulator layer 16d along the vertical axis. However, the upper ends of the columnar conductors v1d, v2d, and v3d are located below the upper main surface of the insulator layer 16d. The columnar conductors v1d, v2d, and v3d have sections in which the thicknesses of the columnar conductors v1d, v2d, and v3d decrease downward. The lower ends of the columnar conductors v1d contact the second ground conductor layer 24. The columnar conductors v1d are aligned in a line along the horizontal axis. The lower ends of the columnar conductors v2d contact the second ground conductor layer 24. The columnar conductors v2d are aligned in a line along the horizontal axis. The lower ends of the columnar conductors v3d contact the second ground conductor layer 24. The plurality of columnar conductors v3d are aligned in a row along the left-right axis.

[0026] The multiple connection conductors v11d, v12d, and v13d are provided in through holes that penetrate the insulator layer 16d along the vertical axis. In this embodiment, the multiple connection conductors v11d, v12d, and v13d are each located above the multiple columnar conductors v1d, v2d, and v3d. As a result, the lower ends of the multiple columnar conductors v1c are in contact with the multiple connection conductors v11d. The upper ends of the multiple columnar conductors v1d are in contact with the multiple connection conductors v11d. As a result, the lower ends of the multiple columnar conductors v1c are connected to the multiple columnar conductors v1d located below the multiple connection conductors 11c via the multiple connection conductors v11d. The lower ends of the multiple columnar conductors v2c are in contact with the multiple connection conductors v12d. The upper ends of the multiple columnar conductors v2d are in contact with the multiple connection conductors v12d. As a result, the lower ends (first columnar conductors) of the multiple columnar conductors v2c are connected to the multiple columnar conductors v2d located below (on the negative side of the Z axis) the multiple columnar conductors v2c (first columnar conductors) via the multiple connecting conductors v12d. The lower ends of the multiple columnar conductors v3c are in contact with the multiple connecting conductors v13d. The upper ends of the multiple columnar conductors v3d are in contact with the multiple connecting conductors v13d. As a result, the lower ends of the multiple columnar conductors v3c are connected to the multiple columnar conductors v3d located below the multiple columnar conductors v3c via the multiple connecting conductors v13d.

[0027] The columnar conductor v10 (second columnar conductor) penetrates the insulator layer 16c (first insulator layer) along the vertical axis. The columnar conductor v10 (second columnar conductor) has a section in which the thickness of the columnar conductor v10 (second columnar conductor) decreases upward (in the positive direction of the Z axis). The upper end (the end on the positive side of the Z axis) of the columnar conductor v10 (second columnar conductor) is in contact with the power supply conductor layer 20b (second conductor layer). The lower end (the end on the negative side of the Z axis) of the columnar conductor v10 (second columnar conductor) is not in contact with any conductor. The lower end (the end on the negative side of the Z axis) of the columnar conductor v10 (second columnar conductor) has a shape that protrudes downward (in the negative direction of the Z axis). When viewed downward, the columnar conductor v10 has a linear shape extending along the horizontal axis. The columnar conductor v10 extends along the power supply conductor layer 20b.

[0028] The upper end (the end on the positive side of the Z axis) of a columnar conductor (fourth columnar conductor) having the following structure is not connected to the signal conductor layer 20a (third conductor layer). The columnar conductor (fourth columnar conductor) penetrates the insulator layer 16c (first insulator layer) along the up-down axis (Z axis). The lower end (the end on the negative side of the Z axis) of the columnar conductor (fourth columnar conductor) is not in contact with any conductor. However, an interlayer connection conductor electrically connected to an external electrode may be connected to the signal conductor layer 20a.

[0029] The protective layer 18a covers the upper main surface of the laminate 12. As a result, the protective layer 18a protects the first ground conductor layer 22. The protective layer 18b covers the lower main surface of the laminate 12. As a result, the protective layer 18b protects the second ground conductor layer 24. The material of the protective layers 18a and 18b is different from the material of the insulator layers 16a to 16d. The protective layers 18a and 18b are, for example, solder resist. The material of the solder resist is, for example, a composition containing an alkali-soluble resin, a photopolymerization initiator, an epoxy resin for improving heat resistance, and inorganic powder.

[0030] The signal conductor layer 20a, power supply conductor layer 20b, first ground conductor layer 22, second ground conductor layer 24, and ground conductor layers 26a, 26b, 28a, 28b, 30a, and 30b are formed by, for example, etching metal foil provided on the upper or lower principal surfaces of the insulator layers 16a to 16d. The metal foil is, for example, copper foil. Thus, the material of the signal conductor layer 20a, the material of the power supply conductor layer 20b, the material of the first ground conductor layer 22, the material of the second ground conductor layer 24, and the materials of the ground conductor layers 26a, 26b, 28a, 28b, 30a, and 30b (the material of the first conductor layer and the material of the second conductor layer) are metals that do not contain resin.

[0031] The columnar conductors v1a, v1b, v2a, v2b, and v3a, v3b are, for example, via-hole conductors. The via-hole conductors are fabricated by forming through-holes in the insulator layers 16a, 16b, filling the through-holes with conductive paste, and sintering the conductive paste. The columnar conductors v1a, v1b, v2a, v2b, and v3a, v3b are made of a mixture of resin and metal.

[0032] Furthermore, the columnar conductors v1c, v1d, v2c, v2d, v3c, v3d, and v10 are, for example, through-hole conductors. The through-hole conductors are fabricated by forming through-holes in the insulator layers 16c, 16d and then metal plating the through-holes. The material of the columnar conductors v1c, v1d, v2c, v2d, v3c, v3d, and v10 is a metal. The metal is, for example, copper. Thus, the material of the columnar conductors v1c, v1d, v2c, v2d, v3c, v3d (the material of the first columnar conductor), and the material of the columnar conductor v10 (the material of the second columnar conductor) are metals that do not contain resin. The material of the signal conductor layer 20a, the material of the power supply conductor layer 20b, the material of the first ground conductor layer 22, the material of the second ground conductor layer 24, the material of the ground conductor layers 26a, 26b, 28a, 28b, 30a, 30b, the material of the plurality of columnar conductors v1c, v1d, the material of the plurality of columnar conductors v2c, v2d, and the material of the plurality of columnar conductors v3c, v3d (the material of the first conductor layer, the material of the second conductor layer, the material of the first columnar conductor, and the material of the second columnar conductor) is the same material.

[0033] Furthermore, the plurality of connecting conductors v11d, v12d, and v13d are fabricated by filling the through holes in which the plurality of columnar conductors v1d, v2d, and v3d are formed with a conductive paste and sintering the conductive paste.

[0034] The connection conductors v11d, v12d, and v13d are a mixture of resin and metal, or may be alloyed metals such as solder.

[0035] [Method of Manufacturing the Multilayer Board 10] Next, a method of manufacturing the multilayer board 10 will be described with reference to the drawings. Figures 3 to 10 are cross-sectional views of the multilayer board 10 during manufacturing.

[0036] 3, the insulator layers 16a to 16c (first insulator layers) are prepared with metal foils 122, 126a, and 126b covering the upper main surfaces (front main surfaces) of the insulator layers 16a to 16c (first insulator layers) (first preparation step).The insulator layer 16d is prepared with metal foil 124 covering the lower main surface of the insulator layer 16d.

[0037] Next, as shown in FIG. 4 , through holes H1a, H2a, and H3a penetrating along the vertical axis (Z-axis) are formed in the insulator layer 16a by irradiating a beam from below the insulator layer 16a. Furthermore, through holes H1b, H2b, and H3b penetrating along the vertical axis (Z-axis) are formed in the insulator layer 16b by irradiating a beam from below the insulator layer 16b. Furthermore, through holes H1c, H2c, and H3c (first through holes) and a second through hole H10 penetrating along the vertical axis (Z-axis) are formed in the insulator layer 16c (first insulator layer) by irradiating a beam from below the insulator layer 16c (through hole forming process). Furthermore, through holes H1d, H2d, and H3d penetrating along the vertical axis (Z-axis) are formed in the insulator layer 16d by irradiating a beam from above the insulator layer 16d. In the through hole formation process, instead of irradiating a beam, through holes H1a, H2a, H3a, H1b, H2b, H3b, H1c, H2c, H3c, H1d, H2d, H3d (first through holes) and second through hole H10 may be formed by wet etching.

[0038] 5, the metal foils 122 and 126a are processed to form the first ground conductor layer 22 and the ground conductor layers 26a, 28a, and 30a (conductor layer forming step). In the conductor layer forming step, the metal foils 122 and 126a are etched using a mask to form the first ground conductor layer 22 and the ground conductor layers 26a, 28a, and 30a.

[0039] Next, as shown in FIG. 6, the through holes H1a, H2a, H3a, H1b, H2b, and H3b are filled with a conductive paste.

[0040] 7, columnar conductors v1c, v2c, v3c, v1d, v2d, v3d and v10 (first and second columnar conductors) are formed in the through holes H1c, H2c, H3c, H1d, H2d, and H3d (first through holes) and the second through hole H10 using the same material as the metal foils 126b and 124 (columnar conductor forming step). In the columnar conductor forming step, an insulator layer 16d (second insulator layer) provided with a columnar conductor v2d (first conductor) is prepared (second preparation step).

[0041] Next, as shown in FIG. 8, a conductive paste is applied onto the columnar conductors v1d, v2d, and v3d.

[0042] 9, the metal foils 126b and 124 are processed to form the second ground conductor layer 24 and the ground conductor layers 26b, 28b, and 30b (conductor layer forming step). In the conductor layer forming step, the metal foils 126b and 124 are etched using a mask to form the second ground conductor layer 24 and the ground conductor layers 26b, 28b, and 30b.

[0043] 10, the insulator layers 16a to 16d including the insulator layer 16c (first insulator layer) and the insulator layer 16d (second insulator layer) are stacked and pressure-bonded together so that the insulator layer 16c (first insulator layer) is positioned above the insulator layer 16d (second insulator layer) (positive side of the Z axis) (pressure-bonding process). In the pressure-bonding process, heat treatment and pressure treatment are performed.

[0044] 2, protective layers 18a and 18b are formed on the pressure-bonded laminate 12. Through the above steps, the multilayer substrate 10 is completed.

[0045] [Effect] In the multilayer substrate 10, the upper end of the columnar conductor v10 is in contact with the power conductor layer 20b. This increases the cross-sectional area of ​​the current path. As a result, the resistance of the current path including the power conductor layer 20b and the columnar conductor v10 can be reduced. In particular, a large current flows through the power conductor layer 20b. Therefore, the resistance value of the power conductor layer 20b is reduced, thereby effectively reducing power loss in the multilayer substrate 10.

[0046] The multilayer substrate 10 does not require an additional process step for forming the columnar conductor v10. More specifically, the columnar conductors v1c, v2c, v3c, and v10 are provided in through holes that penetrate the insulator layer 16c along the vertical axis. This allows the columnar conductor v10 to be formed in the process of forming the columnar conductors v1c, v2c, and v3c. Therefore, the multilayer substrate 10 does not require an additional process step for forming the columnar conductor v10.

[0047] The surface roughness of the lower main surface of the power conductor layer 20b is greater than the surface roughness of the upper main surface of the power conductor layer 20b. However, the columnar conductor v10 is in contact with the lower main surface of the power conductor layer 20b. This reduces the area of ​​the surface with high surface roughness in the power conductor layer 20b. As a result, the resistance of the current path including the power conductor layer 20b and the columnar conductor v10 is reduced.

[0048] The material of the columnar conductor v10 (the material of the second columnar conductor) is a metal that does not contain resin, which reduces the resistance of the columnar conductor v10. This reduces the resistance of the current path including the power supply conductor layer 20b and the columnar conductor v10.

[0049] The columnar conductor v10 (second columnar conductor) has a section in which the thickness of the columnar conductor v10 (second columnar conductor) decreases upward (in the positive direction of the Z axis). That is, the columnar conductor v10 has a tapered shape. This reduces the resistance of the current path including the power conductor layer 20b and the columnar conductor v10 for the following reasons. More specifically, the width of the upper end of the columnar conductor v10 along the left-right axis is smaller than the width of the power conductor layer 20b along the left-right axis. This is to prevent the columnar conductor v10 from protruding from the power conductor layer 20b due to misalignment. However, the width of the lower end of the columnar conductor v10 along the left-right axis is not limited by the width of the power conductor layer 20b along the left-right axis. Therefore, the width of the lower end of the columnar conductor v10 along the left-right axis may be larger than the width of the upper end of the columnar conductor v10 along the left-right axis. This makes the volume of the columnar conductor v10 larger than the volume of a columnar conductor having a uniform thickness, thereby reducing the resistance of the current path including the power supply conductor layer 20b and the columnar conductor v10.

[0050] The lower end face of the columnar conductor v10 has a shape that protrudes downward, which increases the volume of the columnar conductor v10, thereby reducing the resistance of the current path including the power supply conductor layer 20b and the columnar conductor v10.

[0051] (First Modification) A multilayer substrate 10a according to a first modification will be described below with reference to the drawings. Fig. 11 is a cross-sectional view of the multilayer substrate 10a.

[0052] The multilayer substrate 10a differs from the multilayer substrate 10 in that it further includes a columnar conductor v11 (third columnar conductor). The upper end (the end on the positive side of the Z axis) of the columnar conductor v11 (third columnar conductor) is in contact with the power conductor layer 20b (second conductor layer). The lower end (the end on the negative side of the Z axis) of the columnar conductor v11 (third columnar conductor) is not in contact with any conductor. The columnar conductor v10 (second columnar conductor) and the columnar conductor v11 (third columnar conductor) are aligned in the line width direction of the power conductor layer 20b (second conductor layer) when viewed downward (negative direction of the Z axis). Furthermore, the material of the columnar conductor v11 is the same as the material of the columnar conductor v10. The other structure of the multilayer substrate 10a is the same as that of the multilayer substrate 10, so a description thereof will be omitted. The multilayer substrate 10a can achieve the same effects as the multilayer substrate 10.

[0053] The multilayer substrate 10a further includes the columnar conductor v11, which increases the surface area of ​​the conductor connected to the power supply conductor layer 20b. As a result, the multilayer substrate 10a has high heat dissipation properties.

[0054] Second Modification A multilayer substrate 10b according to a second modification will now be described with reference to the drawings. Fig. 12 is a cross-sectional view of the multilayer substrate 10b.

[0055] The multilayer substrate 10b differs from the multilayer substrate 10 in that the signal conductor layer 20a is the second conductor layer. Therefore, the upper end of the columnar conductor v10 is in contact with the signal conductor layer 20a. A high-frequency signal having a frequency of 20 GHz or higher is transmitted to the signal conductor layer 20a (second conductor layer). The other structure of the multilayer substrate 10b is the same as that of the multilayer substrate 10, so a description thereof will be omitted. The multilayer substrate 10b can achieve the same effects as the multilayer substrate 10.

[0056] The multilayer substrate 10b reduces transmission loss in the signal conductor layer 20a. More specifically, high-frequency signals flow near the surface of the signal conductor layer 20a due to the skin effect. Therefore, it is preferable that the surface roughness of the signal conductor layer 20a is small. Therefore, the surface roughness of the lower main surface of the signal conductor layer 20a is greater than the surface roughness of the upper main surface of the signal conductor layer 20a. The columnar conductor v10 is in contact with the lower main surface of the signal conductor layer 20a. This reduces the area of ​​the signal conductor layer 20a with high surface roughness. As a result, transmission loss in the signal conductor layer 20a is reduced.

[0057] (Third Modification) A multilayer substrate 10c according to a third modification will now be described with reference to the drawings. Fig. 13 is a top view of an insulator layer 16c of the multilayer substrate 10c.

[0058] The multilayer substrate 10c differs from the multilayer substrate 10 in the shape of the power conductor layer 20b and the shape of the columnar conductor v10. More specifically, the multilayer substrate 10c has first sections A1a and A1b in which the power conductor layer 20b (second conductor layer) has first line widths w1a and w1b, and second sections A2a and A2b in which the power conductor layer 20b (second conductor layer) has a second line width w2 larger than the first line width w1. The first line width w1a is larger than the first line width w1b. The second line width w2 is the maximum line width of the power conductor layer 20b (second conductor layer). The columnar conductor v10 is provided in the first sections A1a and A1b. The columnar conductor v10 (second columnar conductor) is not provided in the second sections A2a and A2b. The rest of the structure of the multilayer substrate 10c is the same as that of the multilayer substrate 10, so a description thereof will be omitted. The multilayer substrate 10c can achieve the same effects as the multilayer substrate 10.

[0059] In the multilayer substrate 10c, the resistance of the power supply conductor layer 20b tends to be high in the first sections A1a and A1b. Therefore, the columnar conductor v10 is provided in the first sections A1a and A1b. This allows the multilayer substrate 10c to achieve low resistance in the current path including the power supply conductor layer 20b and the columnar conductor v10.

[0060] (Fourth Modification) A multilayer substrate 10d according to a fourth modification will now be described with reference to the drawings. Fig. 14 is a top view of an insulator layer 16c of the multilayer substrate 10d. Fig. 15 is a rear view of the multilayer substrate 10d when in use.

[0061] The multilayer substrate 10d differs from the multilayer substrate 10 in that the columnar conductor v10 is not provided in some sections. More specifically, the multilayer substrate 10d has a third section A3 and a fourth section A4. The third section A3 is bent when viewed in the forward direction (the positive direction of the Y-axis perpendicular to the Z-axis). The columnar conductor v10 (second columnar conductor) is not provided in the third section A3. The rest of the structure of the multilayer substrate 10d is the same as that of the multilayer substrate 10, so a description thereof will be omitted. The multilayer substrate 10d can achieve the same effects as the multilayer substrate 10.

[0062] According to the multilayer substrate 10d, since the columnar conductor v10 is not provided in the third section A3, the third section A3 can be easily bent.

[0063] (Fifth Modification) A multilayer substrate 10e according to a fifth modification will be described below with reference to the drawings. Fig. 16 is a top view of an insulator layer 16c of the multilayer substrate 10e. Fig. 15 is used as a rear view of the multilayer substrate 10e when in use.

[0064] The multilayer substrate 10e differs from the multilayer substrate 10 in that the columnar conductor v10 is not provided in some sections. More specifically, the multilayer substrate 10e has a third section A3 and a fourth section A4. The third section A3 is bent when viewed in the forward direction (the positive direction of the Y-axis perpendicular to the Z-axis). The columnar conductor v10 (second columnar conductor) is provided in the third section A3. The rest of the structure of the multilayer substrate 10e is the same as that of the multilayer substrate 10, so a description thereof will be omitted. The multilayer substrate 10e can achieve the same effects as the multilayer substrate 10.

[0065] In the multilayer substrate 10d, the columnar conductor v10 is provided in the third section A3. When the third section A3 is bent, the columnar conductor v10 undergoes plastic deformation. As a result, the bent state of the third section A3 is easily maintained.

[0066] Other Embodiments The multilayer substrate according to the present invention is not limited to the multilayer substrates 10, 10a to 10e, and can be modified within the scope of the invention. The structures of the multilayer substrates 10, 10a to 10e may be combined in any manner.

[0067] The protective layers 18a and 18b are not essential components.

[0068] The first conductor may be a conductor layer.

[0069] Alternatively, a plurality of small columnar conductors v10 may be arranged along the power supply conductor layer 20b.

[0070] The material of the insulating layers 16a to 16d may be ceramic.

[0071] In addition, the columnar conductor v10 may have a section in which the thickness of the columnar conductor v10 becomes thinner as it goes upward, or the thickness of the columnar conductor v10 as a whole may become thinner as it goes upward.

[0072] The materials of the columnar conductors v1c, v2c, and v3c (the first columnar conductor and the second columnar conductor) may be the same, but may be different from the materials of the signal conductor layer 20a, the power conductor layer 20b, the first ground conductor layer 22, the second ground conductor layer 24, the ground conductor layers 26a, 26b, 28a, 28b, 30a, and 30b, the columnar conductors v1d, v2d, and v3d.

[0073] In FIG. 13, the width of the stack 12 in the first section A1b in the direction along the longitudinal axis may be smaller than the width of the stack 12 in the first section A1a in the direction along the longitudinal axis.

[0074] The bottom end of the columnar conductor v1c may be in contact with the columnar conductor v1d located below the columnar conductor v1c. In other words, contact is a subordinate concept to connection.

[0075] 2, the connection conductors v11d to v13d are located in through holes provided in the insulating layer 16d, but the connection conductors v11d to v13d may also be located in through holes provided in the insulating layer 16c. In other words, the connection conductors may be located at either the connection destination or the connection source.

[0076] 2, the columnar conductors v1c, v2c, and v3c are electrically connected to the columnar conductors v1d, v2d, and v3d via the connecting conductors v11d, v12d, and v13d, respectively. However, the present invention is not limited to connecting the columnar conductors to each other via the connecting conductors. For example, the connecting conductors v1c, v2c, and v3c may be electrically connected to a conductor layer made of a metal foil such as copper foil. In such an example, the columnar conductors v1c, v2c, and v3c are electrically connected to the conductor layer via the connecting conductors v11d, v12d, and v13d.

[0077] The multilayer substrate according to the present invention has the following structure.

[0078] (1) A semiconductor device including at least a laminate, a first conductor layer, a second conductor layer, a first columnar conductor, a second columnar conductor, and a connecting conductor, wherein the laminate has a structure in which a plurality of insulator layers including a first insulator layer are stacked along the Z axis, the first insulator layer has a positive main surface and a negative main surface located on the negative side of the Z axis from the positive main surface, the first conductor layer and the second conductor layer are located on the positive main surface of the first insulator layer, the first columnar conductor and the second columnar conductor are provided inside a through hole penetrating the first insulator layer along the Z axis, an end of the first columnar conductor on the positive side of the Z axis contacts the first conductor layer, the connecting conductor is a conductor that electrically connects conductors in the stacking direction, an end of the first columnar conductor on the negative side of the Z axis is connected to the columnar conductor or the conductor layer via the connecting conductor, and an end of the second columnar conductor on the positive side of the Z axis contacts the second conductor layer, a negative end of the second columnar conductor in the Z-axis direction is not in contact with any conductor; and the first columnar conductor and the second columnar conductor are made of the same material.

[0079] (2) The multilayer substrate according to (1), wherein the material of the first columnar conductor and the material of the second columnar conductor are metals that do not contain resin.

[0080] (3) The multilayer substrate according to either (1) or (2), wherein the first columnar conductor has a section in which the thickness of the first columnar conductor decreases in the positive direction of the Z axis, and the second columnar conductor has a section in which the thickness of the second columnar conductor decreases in the positive direction of the Z axis.

[0081] (4) The multilayer substrate according to any one of (1) to (3), wherein the end face of the second columnar conductor on the negative side of the Z axis has a shape that protrudes in the negative direction of the Z axis.

[0082] (5) The multilayer substrate according to any one of (1) to (4), wherein the second conductor layer has a linear shape when viewed in the negative direction of the Z axis.

[0083] (6) The multilayer substrate according to (5), further comprising a third columnar conductor, wherein an end of the third columnar conductor on the positive side of the Z axis is in contact with the second conductor layer, an end of the third columnar conductor on the negative side of the Z axis is not in contact with any conductor, the second columnar conductor and the third columnar conductor are aligned in the line width direction of the second conductor layer when viewed in the negative direction of the Z axis, and the material of the second columnar conductor is the same as the material of the first columnar conductor.

[0084] (7) The multilayer substrate according to either (5) or (6), wherein the second conductor layer has a first section in which the second conductor layer has a first line width and a second section in which the second conductor layer has a second line width larger than the first line width, the second line width being the maximum line width of the second conductor layer, the second columnar conductor being provided in the first section, and the second columnar conductor being not provided in the second section.

[0085] (8) The multilayer substrate according to either (5) or (6), wherein the multilayer substrate has a third section and a fourth section, the third section is bent when viewed in the positive direction of a Y-axis perpendicular to the Z-axis, and the second columnar conductor is not provided in the third section.

[0086] (9) The multilayer substrate according to either (5) or (6), wherein the multilayer substrate has a third section and a fourth section, the third section is bent when viewed in a positive direction of a Y-axis perpendicular to the Z-axis, and the second columnar conductor is provided in the third section.

[0087] (10) The multilayer substrate according to any one of (1) to (9), further comprising a third conductor layer, the third conductor layer being located on the positive main surface of the first insulator layer, the end of the fourth columnar conductor on the positive side of the Z axis not being connected to the third conductor layer, the fourth columnar conductor penetrating the first insulator layer along the Z axis, and the end of the fourth columnar conductor on the negative side of the Z axis not contacting any conductor.

[0088] (11) The multilayer substrate according to any one of (1) to (10), wherein the second conductor layer has a positive main surface and a negative main surface located on the negative side of the Z axis from the positive main surface of the second conductor layer, and the surface roughness of the negative main surface of the second conductor layer is greater than the surface roughness of the positive main surface of the second conductor layer.

[0089] (12) The multilayer substrate according to (11), further comprising a signal conductor layer through which a high-frequency signal having a frequency of 20 GHz or more is transmitted.

[0090] (13) The multilayer substrate according to any one of (1) to (12), wherein the material of the first conductor layer, the material of the second conductor layer, the material of the first columnar conductor, and the material of the second columnar conductor are the same material.

[0091] (14) A method for manufacturing a multilayer substrate includes a first preparation step, a through hole forming step, a conductor layer forming step, a columnar conductor forming step, a second preparation step, and a crimping step, wherein the first preparation step includes preparing a first insulator layer having a positive main surface and a negative main surface located on the negative side of the positive main surface along the Z axis, the first insulator layer being provided with metal foil covering the positive main surface, the through hole forming step including forming a first through hole and a second through hole penetrating along the Z axis in the first insulator layer, the conductor layer forming step including processing the metal foil to form a first conductor layer and a second conductor layer, the columnar conductor forming step including forming a first columnar conductor and a second columnar conductor in each of the first through hole and the second through hole, and the second preparation step including preparing a second insulator layer provided with a connecting conductor, a first insulating layer and a second insulating layer, the first insulating layer being positioned on the positive side of the Z axis relative to the second insulating layer; an end of the first columnar conductor on the positive side of the Z axis being in contact with the first conductor layer; an end of the second columnar conductor on the positive side of the Z axis being in contact with the second conductor layer; and an end of the first columnar conductor on the negative side of the Z axis being connected to the connecting conductor.

[0092] (15) The method for manufacturing a multilayer substrate according to (14), wherein the through hole forming step forms the first through hole and the second through hole by beam irradiation or wet etching.

[0093] 10, 10a to 10e: Multilayer substrate 12: Laminate 16a to 16d: Insulator layer 16c: First insulator layer 16d: Second insulator layer 18a, 18b: Protective layer 20a: Signal conductor layer 20b: Power supply conductor layer (second conductor layer) 22: First ground conductor layer 24: Second ground conductor layer 26a, 26b, 28a, 28b, 30a, 30b: Ground conductor layer 26b, 28b, 30b: Ground conductor layer (first conductor layer) A1a, A1b: First section A2a: Second section A3: Third section A4: Fourth section H10: Second through hole H1a to H1d: Through holes v1a to v1d, v2a to v2d, v3a to v3d, v10, v11: Columnar conductor v1c, v2c, v3c, v1d, v2d, v3d: columnar conductor (first columnar conductor) v10: columnar conductor (second columnar conductor) v11: columnar conductor (third columnar conductor) v11d, v12d, v13d: connecting conductors

Claims

1. A laminate, comprising at least a first conductor layer, a second conductor layer, a first columnar conductor, a second columnar conductor, and a connection conductor, wherein the laminate has a structure in which a plurality of insulator layers including a first insulator layer are laminated along the Z-axis, the first insulator layer has a positive main surface and a negative main surface located on the negative side of the Z-axis with respect to the positive main surface, the first conductor layer and the second conductor layer are located on the positive main surface of the first insulator layer, the first columnar conductor and the second conductor layer are provided inside a through hole that penetrates the first insulator layer along the Z-axis, an end portion of the first columnar conductor on the positive side of the Z-axis is in contact with the first conductor layer, the connection conductor is a conductor that electrically connects conductors in the stacking direction, an end portion of the first columnar conductor on the negative side of the Z-axis is connected to a columnar conductor or a conductor layer via the connection conductor, the second columnar conductor is a conductor that extends in the front-rear direction perpendicular to the Z-axis, and is columnar in the Z-axis direction in a cross-sectional view with a plane perpendicular to the front-rear direction as a cross-section, an end portion of the second columnar conductor on the positive side of the Z-axis is in contact with the second conductor layer, an end portion of the second columnar conductor on the negative side of the Z-axis is not in contact with any conductor, the material of the connection conductor is different from the materials of the first columnar conductor and the second columnar conductor, a multilayer substrate.

2. The materials of the first columnar conductor and the second columnar conductor are metals that do not contain resin, The multilayer substrate according to Claim 1.

3. The first columnar conductor has a section in which the thickness of the first columnar conductor becomes thinner as going in the positive direction of the Z-axis, the second columnar conductor has a section in which the thickness of the second columnar conductor becomes thinner as going in the positive direction of the Z-axis, The multilayer substrate according to Claim 1 or Claim 2.

4. An end face of the second columnar conductor on the negative side of the Z-axis has a shape that protrudes in the negative direction of the Z-axis, The multilayer substrate according to Claim 1 or Claim 2.

5. The second conductor layer has a linear shape when viewed in the negative direction of the Z-axis, The multilayer substrate according to Claim 1 or Claim 2.

6. The multilayer substrate further includes a third columnar conductor, the third columnar conductor is a conductor that extends in the front-rear direction perpendicular to the Z-axis, and is columnar in the Z-axis direction in a cross-sectional view with a plane perpendicular to the front-rear direction as a cross-section, an end portion of the third columnar conductor on the positive side of the Z-axis is in contact with the second conductor layer, The end portion on the negative side of the Z-axis of the third columnar conductor is not in contact with any conductor. The second columnar conductor and the third columnar conductor are arranged side by side in the line width direction of the second conductor layer when viewed in the negative direction of the Z-axis. The material of the second columnar conductor and the material of the first columnar conductor are different from the material of the access conductor. The multilayer substrate according to claim 5.

7. The multilayer substrate has a first section in which the second conductor layer has a first line width and a second section in which the second conductor layer has a second line width greater than the first line width. The second line width is the maximum value of the line width of the second conductor layer. The second columnar conductor is provided in the first section. The second columnar conductor is not provided in the second section. The multilayer substrate according to claim 5.

8. The multilayer substrate has a third section and a fourth section. The third section is bent when viewed in the positive direction of the Y-axis orthogonal to the Z-axis. The second columnar conductor is not provided in the third section. The multilayer substrate according to claim 5.

9. The multilayer substrate has a third section and a fourth section. The third section is bent when viewed in the positive direction of the Y-axis orthogonal to the Z-axis. The second columnar conductor is provided in the third section. The multilayer substrate according to claim 5.

10. The multilayer substrate further includes a third conductor layer and a fourth columnar conductor. The third conductor layer is located on the positive main surface of the first insulator layer. The end portion on the positive side of the Z-axis of the fourth columnar conductor is not connected to the third conductor layer. The fourth columnar conductor penetrates the first insulator layer along the Z-axis. The end portion on the negative side of the Z-axis of the fourth columnar conductor is not in contact with any conductor. The multilayer substrate according to claim 1 or claim 2.

11. The second conductor layer has a positive main surface and a negative main surface located on the negative side of the Z-axis with respect to the positive main surface of the second conductor layer. The surface roughness of the negative main surface of the second conductor layer is greater than the surface roughness of the positive main surface of the second conductor layer. The multilayer substrate according to claim 1 or claim 2.

12. Comprising a signal conductor layer for transmitting a high-frequency signal having a frequency of 20 GHz or higher. The multilayer substrate according to claim 1 or claim 2.

13. The material of the first conductor layer, the material of the second conductor layer, the material of the first columnar conductor, and the material of the second columnar conductor are different from the material of the access conductor. The multilayer substrate according to claim 1 or claim 2.

14. A method for manufacturing a multilayer substrate, comprising a first preparation step, a through-hole formation step, a conductor layer formation step, a columnar conductor formation step, a second preparation step, and a pressure bonding step. In the first preparation step, a first insulator layer having a positive main surface and a negative main surface located on the negative side of the Z-axis with respect to the positive main surface, and provided with a metal foil covering the positive main surface, is prepared. In the through-hole formation step, a first through-hole penetrating along the Z-axis is formed in the first insulator layer, and a groove-shaped second through-hole extending in the front-rear direction orthogonal to the Z-axis is formed in the first insulator layer. In the conductor layer formation step, a first conductor layer and a second conductor layer are formed by processing the metal foil. In the columnar conductor formation step, a first columnar conductor and a second columnar conductor are formed in each of the first through-hole and the second through-hole. In the second preparation step, a second insulator layer provided with a connection conductor is prepared. In the pressure bonding step, a plurality of insulator layers including the first insulator layer and the second insulator layer are laminated and pressure bonded so that the first insulator layer is located on the positive side of the Z-axis with respect to the second insulator layer. The end portion of the first columnar conductor on the positive side of the Z-axis is in contact with the first conductor layer. The end portion of the second columnar conductor on the positive side of the Z-axis is in contact with the second conductor layer. The end portion of the first columnar conductor on the negative side of the Z-axis is connected to the connection conductor. A method for manufacturing a multilayer substrate.

15. In the through-hole formation step, the first through-hole and the second through-hole are formed by irradiation of a beam or wet etching. The method for manufacturing a multilayer substrate according to claim 14.