Substrate equipped with built-in through-conductors

Abstract

Provided is a substrate (1) equipped with built-in through-conductors, comprising: a substrate (10) that is provided with a first main surface (11) and a second main surface (12) opposite to the first main surface, the substrate (10) being provided with a plurality of through-holes (20); through-conductors (30) inserted into the through-holes (20); and a metal layer (70) that spreads in the same planar direction as the first main surface (11) and is connected to the through-conductors (30). The through-holes (20) are provided with a first through-hole (21) and a second through-hole (22) that are different through-holes. The through-conductors (30) are provided with a first through-conductor (31) and a second through-conductor (32) that are connected to the metal layer (70). The first through-conductor (31) is in contact with or in proximity to an inner peripheral wall (26) on the side of the first through-hole (21) that is distant from the second through-hole (22). The second through-conductor (32) is in contact with or in proximity to an inner peripheral wall (26) on the side of the second through-hole (22) that is distant from the first through-hole (21).

Description

Through conductor built-in board

[0001] The present invention relates to a substrate with built-in through conductors.

[0002] Patent document 1 discloses a glass substrate having a through conductor formed in a through hole that penetrates the glass substrate in the thickness direction, and a resin body that is arranged between the through conductor and the through hole and surrounds the through conductor.

[0003] Japanese Patent Application Laid-Open No. 2020-047643

[0004] In the structure described in Patent Document 1, a wiring layer may be provided on the glass substrate, or a heat dissipation layer made of metal may be provided to dissipate heat from the heat spreader. These wiring layers and heat dissipation layers are connected to the through conductors.

[0005] The wiring layer and heat sink undergo thermal expansion due to a rise in the temperature of the environment in which they are used. In particular, the temperature rise caused by the use of semiconductors and other devices connected to the glass substrate can cause them to heat up to temperatures higher than room temperature. In this case, the wiring layer and heat sink have a higher thermal expansion coefficient than the glass substrate, so they expand in a planar direction relative to the glass substrate when heated. Because the through conductors are connected to the wiring layer and heat sink, stress is applied to the through conductors so that they move in a planar direction relative to the glass substrate.

[0006] In the technology described in Patent Document 1, the through conductor is surrounded by a resin body. Because the resin is a soft material compared to the through conductor, when stress is applied to the through conductor to move in the planar direction of the glass substrate, the resin body cannot prevent the movement of the through conductor, and the through conductor deforms the resin body and moves in the planar direction of the glass substrate due to the stress. This movement of the through conductor can cause problems such as warping of the glass substrate.

[0007] The present invention has been made to solve the above problems, and aims to provide a substrate with built-in through conductors in which the through conductors inserted into the through holes are prevented from moving due to thermal stress.

[0008] The substrate with built-in through conductors of the present invention comprises a substrate having a first main surface and a second main surface opposite to the first main surface, and having a plurality of through holes extending from the first main surface along the second main surface, through conductors inserted into the through holes, and a metal layer extending in the same plane direction as the first main surface and connected to the through conductors, the through holes comprising first and second through holes which are different through holes, the through conductors comprising a first through conductor inserted into the first through hole and a second through conductor inserted into the second through hole, The first through conductor and the second through conductor are both connected to the metal layer, and when a straight line passing through the center of the first through hole and the center of the second through hole is taken as a first reference line, the first through conductor is in contact with or close to a first intersection point between the inner wall of the first through hole and the first reference line, which is the intersection point farther from the second through hole, and the second through conductor is in contact with or close to a second intersection point between the inner wall of the second through hole and the first reference line, which is the intersection point farther from the first through hole.

[0009] Further, according to another aspect of the present invention, there is provided a substrate with built-in through conductors, the substrate comprising: a first main surface and a second main surface opposite to the first main surface, the substrate having a plurality of through holes extending from the first main surface along the second main surface; through conductors inserted into the through holes; and a metal layer extending in the same plane direction as the first main surface and connected to the through conductors, the through holes comprising third through holes, fourth through holes, and fifth through holes which are different through holes; the through conductors comprising a third through hole inserted into the third through hole, a fourth through hole inserted into the fourth through hole, and a fifth through hole inserted into the fifth through hole; the third through conductor, the fourth through hole, and the fifth through conductor are all connected to the metal layer; a line passing through the center of the third through hole and the center of the fourth through hole is defined as a third reference line; a line passing through the center of the fourth through hole and the center of the fifth through hole is defined as a fourth reference line; When the third through conductor is a reference line, the third through conductor is in contact with or close to a portion between a third intersection, which is an intersection point farther from the fourth through hole among the intersections of the inner wall of the third through hole and the third reference line, and a fourth intersection, which is an intersection point farther from the fifth through hole among the intersections of the inner wall of the third through hole and the fifth reference line, the fourth through conductor is in contact with or close to a portion between a fifth intersection, which is an intersection point farther from the fifth through hole among the intersections of the inner wall of the fourth through hole and the fourth reference line, and a sixth intersection, which is an intersection point farther from the third through hole among the intersections of the inner wall of the fourth through hole and the third reference line, the fifth through conductor is in contact with or close to a portion between a seventh intersection, which is an intersection point farther from the third through hole among the intersections of the inner wall of the fifth through hole and the fifth reference line, and an eighth intersection, which is an intersection point farther from the fourth through hole among the intersections of the inner wall of the fifth through hole and the fourth reference line.

[0010] According to the present invention, it is possible to provide a substrate with built-in through conductors in which the through conductors inserted into the through holes are prevented from moving due to thermal stress.

[0011] FIG. 1 is a top view of a substrate with built-in through conductors according to an embodiment of the present invention, viewed from the first main surface side of the substrate. FIG. 2 is a top view of an extracted region S portion of the substrate with built-in through conductors shown in FIG. 1. FIG. 3 is a cross-sectional view of the substrate with built-in through conductors shown in FIG. 1 taken along line A-A, illustrating a configuration including metal layers on the first and second main surfaces of the substrate. FIG. 4 is an explanatory diagram illustrating the positional relationship when the through conductors and intersections are close to each other. FIG. 5 is a top view showing three through holes and through conductors of interest. FIG. 6 is an explanatory diagram illustrating the positional relationship when the through conductors are close to a portion between the intersections. FIG. 7 is a top view showing the positional relationship between two through holes, through conductors, and metal layers of interest. FIG. 8 is a top view showing the positional relationship between two through holes, through conductors, and metal layers of interest. FIG. 9 is a top view showing the positional relationship between three through holes, through conductors, and metal layers of interest. FIG. 10 is a cross-sectional view schematically illustrating a form in which the through conductors are in line contact with the inner circumferential wall of the through hole into which they are inserted. Fig. 11 is a cross-sectional view schematically showing a configuration in which the length of the through conductor is shorter than the length of the through hole. Fig. 12 is a cross-sectional view schematically showing a configuration in which irregularities are provided on the side surface of the through conductor. Fig. 13 is a cross-sectional view schematically showing a configuration in which irregularities are provided on the inner peripheral wall of the through hole.

[0012] The following describes the substrate with built-in through conductors of the present invention. However, the present invention is not limited to the following configuration, and can be modified as appropriate within the scope of the present invention. Note that a combination of two or more of the individual desirable configurations described below also constitutes the present invention.

[0013] [Substrate with built-in through conductors] Fig. 1 is a top view of a substrate with built-in through conductors according to an embodiment of the present invention, viewed from the first main surface side of the substrate. In Fig. 1, the metal layer on the first main surface side of the substrate is omitted so that the through holes and through conductors can be seen. Fig. 2 is a top view of an extracted region S portion of the substrate with built-in through conductors shown in Fig. 1. Fig. 3 is a cross-sectional view of the substrate with built-in through conductors shown in Fig. 1 taken along line A-A, showing the configuration including the metal layers on the first and second main surface sides of the substrate.

[0014] The substrate 1 with built-in through conductors shown in Figure 1 shows a first main surface 11 of a substrate 10. A plurality of through holes 20 are provided in the substrate 10, and through conductors 30 are inserted into the through holes 20. The substrate with built-in through conductors as a whole is provided with a plurality of through holes and a plurality of through conductors. Since one through conductor is inserted into one through hole, it can be said that the substrate with built-in through conductors has a plurality of through holes, each with one through conductor inserted. Figure 1 also shows resin 60 filled between the through conductors 30 and the through holes 20.

[0015] FIG. 3 shows a cross section of the substrate 10. The substrate 10 has a first main surface 11 and a second main surface 12 opposite the first main surface 11, and is provided with a plurality of through holes 20 extending from the first main surface 11 along the second main surface 12. The substrate is preferably made of a material with high rigidity. The material preferably has a thermal expansion coefficient smaller than that of the metal layer and is harder than the resin filled in the through holes. As an index of rigidity, the material preferably has a Young's modulus of 10 GPa or more and 50 GPa or less. The substrate material is preferably a substrate containing glass. A glass-containing substrate has high rigidity, a thermal expansion coefficient smaller than that of the metal layer, and is harder than the resin filled in the through holes. An example of a glass-containing substrate is a composite substrate of resin and glass. Specific examples of glass constituting a glass-containing substrate include E-glass, and specific examples of resins include epoxy resins. An example of a resin-glass composite substrate is a glass-epoxy substrate. The thickness of the substrate is preferably 0.3 mm or more and 5.0 mm or less. The thermal expansion coefficient of the substrate is 4×10 －６ / K or more, 14×10 －６ / K or less is preferable.

[0016] The substrate is provided with a plurality of through holes, and a through conductor is inserted into each through hole. The through holes preferably have a circular shape in top view, and a diameter of 0.3 mm or more and 5 mm or less. The length (thickness) of the through holes is the same as the thickness of the substrate.

[0017] The through conductor is made of a material that is an electrical conductor and / or a thermal conductor. The through conductor is preferably a metallic material. Metallic materials are usually electrical conductors and thermal conductors. Copper is a preferred metallic conductor. Non-metallic through conductors include ceramic materials and carbon materials, many of which can be used as thermal conductors, and some can also be used as electrical conductors. Examples include silicon carbide, aluminum nitride, alumina, and graphite. The through conductor is preferably a material with an electrical resistivity of 0.017 μΩ·m or more and 0.022 μΩ·m or less. Furthermore, the through conductor is preferably a material with a thermal conductivity of 300 W / m·K or more and 400 W / m·K or less. Furthermore, the thermal expansion coefficient of the through conductor is 17×10 －６ / K or more, 70×10 －６ / K or less. Furthermore, the Young's modulus of the through conductor is preferably 50 GPa or more and 300 GPa or less. The shape of the through conductor is preferably cylindrical (circular in top view), and when the through conductor is cylindrical, the diameter of the bottom surface is preferably 0.2 mm or more and 4.9 mm or less. Furthermore, regardless of the top view shapes of the through conductor and the through hole, the area ratio of the top view area of ​​the through conductor to the top view area of ​​the through hole is preferably 96% or less. The length of the through conductor (the length along the thickness direction of the through hole) may be the same as the length of the through hole, or may be shorter than the length of the through hole.

[0018] It is preferable that a resin be filled between the through conductor and the through hole into which the through conductor is inserted. Specific examples of the resin include epoxy resin, silicone resin, acrylic resin, and polyimide resin. The resin is usually a material softer than the through conductor and the substrate.

[0019] In the substrate with built-in through conductors of the present invention, the positions of the through conductors within the through holes are specified by focusing on a specific number (two or three) of through holes provided in the substrate and into which the through conductors are inserted. First, an embodiment focusing on two through holes will be described. In a top view such as that shown in Figure 1, through holes that satisfy the relationship defined in the present invention are selected and focused on. In Figure 1, the focus is on through holes included in the area shown as area S.

[0020] The following relationship holds between the two through holes of interest. That is, when a straight line passing through the centers of the first through hole and the second through hole is defined as a first reference line, the first through conductor is in contact with or close to a first intersection point between the inner circumferential wall of the first through hole and the first reference line, which is the intersection point farther from the second through hole, and the second through conductor is in contact with or close to a second intersection point between the inner circumferential wall of the second through hole and the first reference line, which is the intersection point farther from the first through hole. Furthermore, there may or may not be another through hole of interest between the two through holes of interest. The above-mentioned conditions satisfied by the two through holes of interest will be described with reference to FIG. 2 .

[0021] Fig. 2 shows the through holes and through conductors included in region S. In Fig. 2, the through holes and through conductors shown on the left side are first through hole 21 and first through conductor 31, and the through holes and through conductors shown on the right side are second through hole 22 and second through conductor 32. These are the two through holes and through conductors of interest in region S. The through holes and through conductors shown in the center are through hole 120 and through conductor 130, which are not of interest.

[0022] A straight line passing through the center C1 of the first through hole 21 and the center C2 of the second through hole 22 is defined as a first reference line 41. There are two intersections between the inner circumferential wall of the first through hole 21 and the first reference line 41, and the intersection farther from the second through hole 22 is defined as a first intersection (reference number 101). The intersection closer to the second through hole 22 is defined as an eleventh intersection (reference number 111). Similarly, there are two intersections between the inner circumferential wall of the second through hole 22 and the first reference line 41, and the intersection farther from the first through hole 21 is defined as a second intersection (reference number 102). The intersection closer to the first through hole 21 is defined as a twelfth intersection (reference number 112).

[0023] The first through conductor 31 is inserted into the first through hole 21 and is located within the first through hole 21 on the side farther from the second through hole 22. This is expressed as the first through conductor 31 being in contact with or close to the first intersection 101. The first through conductor 31 is also spaced apart from the eleventh intersection 111, which is the intersection closer to the second through hole 22. Fig. 2 shows an aspect in which the left end of the first through conductor 31 is in contact with the first intersection 101.

[0024] The second through conductor 32 is inserted into the second through hole 22 and is located within the second through hole 22 on the side farther from the first through hole 21. This is expressed as the second through conductor 32 being in contact with or close to the second intersection 102. The second through conductor 32 is also spaced apart from the twelfth intersection 112, which is the intersection closer to the first through hole 21. Fig. 2 shows an aspect in which the right end of the second through conductor 32 is in contact with the second intersection 102.

[0025] In this specification, with regard to "the through conductor is in contact with or close to the intersection," if the through conductor is the first through conductor, the intersection that is in contact with or close to the first intersection, and if the through conductor is the second through conductor, the intersection that is in contact with or close to the second intersection. When the through conductor is in contact with the intersection, it is in the form shown in FIG. 2, and it is visually determined whether the through conductor is in a positional relationship in which it is in contact with the intersection when viewed from above. When the through conductor is close to the intersection, it means that the through conductor is not in contact with the intersection but is present in the vicinity of the intersection. This positional relationship can also be visually determined when viewed from above.

[0026] A case where a through conductor is close to an intersection will be described with reference to FIG. 4 . FIG. 4 is an explanatory diagram illustrating the positional relationship when a through conductor and an intersection are close to each other, showing the relationship between the first through conductor 31, the first through hole 21, and the first intersection 101. First, the point where the distance between the side surface (outer periphery) of the first through conductor 31 and the inner peripheral wall 26 of the first through hole 21 is focused, and that distance, i.e., the shortest distance between the first through conductor 31 and the inner peripheral wall 26 of the first through hole 21 (indicated by a double-headed arrow R1 in FIG. 4 ), is measured. A point on the side surface of the first through conductor 31 is designated as the closest point 31r. Separately, a sector is drawn, centered on the radius connecting the center C1 of the first through hole 21 and the first intersection, extending 30° on both sides of the radius (60° in total), including an arc from the first intersection 101 along the inner peripheral wall of the first through hole 21. If the nearest point 31 r is within the sector shape, it can be said that the first through conductor 31 is located on the far side from the second through hole 22 within the first through hole 21 .

[0027] Furthermore, to determine that the first through conductor 31 and the first intersection 101 are close to each other, the shortest distance R1 (indicated by the double-headed arrow R1 in FIG. 4 ) between the first through conductor 31 and the inner peripheral wall 26 of the first through hole 21 must be relatively short, and it is preferable that the shortest distance R1 be 20 μm or less. Furthermore, when the longest distance R2 (indicated by the double-headed arrow R2 in FIG. 4 ) between the first through conductor 31 and the inner peripheral wall 26 of the first through hole 21 is used as an indicator of whether the shortest distance between the first through conductor 31 and the inner peripheral wall 26 of the first through hole 21 is relatively short, the proximity rate can be expressed as [(R2-R1) / (R1+R2)]×100(%), and it is preferable that this proximity rate value be 50% or more. Furthermore, it is more preferable that the proximity rate be 70% or more, and even more preferable that it be 90% or more. The same applies to the relationship between the second through hole and the second through conductor.

[0028] 3 is a cross-sectional view of the through conductor-embedded substrate shown in FIG. 1 taken along line A-A, illustrating the configuration including the metal layers on the first and second main surfaces of the substrate. A metal layer 71 extending in the same plane as the first main surface 11 of the substrate 10 is provided on the first main surface 11, and a metal layer 72 extending in the same plane as the second main surface 12 is provided on the second main surface 12. The first through conductors 31 and the second through conductors 32 are both connected to the metal layer 71 and the metal layer 72. It is sufficient for the through conductor-embedded substrate to have at least a metal layer (metal layer 71) extending in the same plane as the first main surface of the substrate; it is not necessary for the second main surface of the substrate to have a metal layer. The metal layer is preferably a metal foil or a metal plating layer, and is preferably a copper foil or a copper plating layer. The thermal expansion coefficient of the metal layer is usually higher than the thermal expansion coefficient of the substrate.

[0029] 3 shows a state in which the first through conductor 31 is positioned to the left of the first through hole 21 and is in contact with the substrate 10 (in contact with the inner peripheral wall 26 of the first through hole 21). Also, a state in which the second through conductor 32 is positioned to the right of the second through hole 22 and is in contact with the substrate 10 (in contact with the inner peripheral wall 26 of the second through hole 22). Also, the first through conductor 31 and the second through conductor 32 are connected to the metal layer 71.

[0030] When the substrate 1 with built-in through conductors is heated and the metal layer 71 expands in a planar direction relative to the substrate 10, stress is applied to the first through conductors 31 and the second through conductors 32 so that they move in a planar direction relative to the substrate 10, because the thermal expansion coefficient of the metal layer 71 is greater than that of the substrate 10. This stress is applied outward, that is, stress is applied to the first through conductor 31 to the left in the drawing and stress is applied to the second through conductor 32 to the right in the drawing. In Figure 3, the direction of the stress is indicated by a left-pointing arrow from the first through conductor 31 and a right-pointing arrow from the second through conductor 32.

[0031] The first through conductor 31 contacts the substrate 10 on its left side. Because the substrate 10 is made of a highly rigid material, the first through conductor 31 cannot deform the substrate 10 and move. Similarly, the second through conductor 32 contacts the substrate 10 on its right side. Because the substrate 10 is made of a highly rigid material, the second through conductor 32 cannot deform the substrate 10 and move. In other words, even if the through conductor-embedded substrate is heated and stress is applied to the first through conductor and the second through conductor so that they move in the planar direction of the substrate, the first through conductor and the second through conductor are prevented from moving in the planar direction of the substrate. Therefore, with the above configuration, a through conductor-embedded substrate can be obtained in which the through conductors inserted in the through holes are prevented from moving due to thermal stress.

[0032] The presence of the through conductor 130 inserted into the through hole 120 not of interest, shown in the center of FIG. 3, is not relevant to achieving the above-mentioned effect.

[0033] In the substrate with built-in through conductors of the present invention, 30 or more through conductors are connected to one metal layer, and it is preferable that the percentage of through conductors connected to the metal layer in which the centers of the through holes into which the through conductors are inserted are misaligned with the centers of the through conductors is 10% or more. The top view shown in FIG. 1 shows 20 through holes 20 and through conductors 30, and the through conductors 30 are connected to a metal layer (not shown) (metal layer 71 shown in FIG. 3). Of the 20 through conductors 30 shown in FIG. 1, the centers of the through holes into which the through conductors are inserted are misaligned with the centers of the through conductors except for the through conductor shown in the center of region S. Here, "the centers of the through holes into which the through conductors are inserted are misaligned with the centers of the through conductors" refers only to the misalignment of the centers, regardless of the orientation of the through conductors within the through holes. As a guide to the misalignment of the centers, a circle with a diameter 10% of the diameter of the through hole and centered on the center of the through hole is drawn. If the center of the through conductor is not located within the circle, it is determined that the centers of the through holes and the through conductors are misaligned.

[0034] Up to this point, we have described an embodiment that focuses on two specific through holes among the through holes into which the through conductors are inserted, but below we will describe an embodiment that focuses on three specific through holes.

[0035] Fig. 5 is a top view showing three through holes and through conductors of interest. In Fig. 5, the through holes and through conductors shown in the upper left are the third through hole 23 and third through conductor 33, the through holes and through conductors shown in the upper right are the fourth through hole 24 and fourth through conductor 34, and the through holes and through conductors shown in the lower center are the fifth through hole 25 and fifth through conductor 35. These are the three through holes and through conductors of interest.

[0036] A line passing through the center C3 of the third through hole 23 and the center C4 of the fourth through hole 24 is defined as a third reference line 43. A line passing through the center C4 of the fourth through hole 24 and the center C5 of the fifth through hole 25 is defined as a fourth reference line 44. A line passing through the center C5 of the fifth through hole 25 and the center C3 of the third through hole 23 is defined as a fifth reference line 45.

[0037] There are two intersections between the inner peripheral wall of the third through hole 23 and the third reference line 43, and the intersection farther from the fourth through hole 24 is referred to as the third intersection (reference number 103). The intersection closer to the fourth through hole 24 is referred to as the thirteenth intersection (reference number 113). There are two intersections between the inner peripheral wall of the third through hole 23 and the fifth reference line 45, and the intersection farther from the fifth through hole 25 is referred to as the fourth intersection (reference number 104). The intersection closer to the fifth through hole 25 is referred to as the fourteenth intersection (reference number 114).

[0038] There are two intersections between the inner peripheral wall of the fourth through hole 24 and the fourth reference line 44, and the intersection farther from the fifth through hole 25 is referred to as the fifth intersection (reference number 105). The intersection closer to the fifth through hole 25 is referred to as the fifteenth intersection (reference number 115). There are two intersections between the inner peripheral wall of the fourth through hole 24 and the third reference line 43, and the intersection farther from the third through hole 23 is referred to as the sixth intersection (reference number 106). The intersection closer to the third through hole 23 is referred to as the sixteenth intersection (reference number 116).

[0039] There are two intersections between the inner peripheral wall of the fifth through hole 25 and the fifth reference line 45, and the intersection farther from the third through hole 23 is designated as the seventh intersection (reference number 107). The intersection closer to the third through hole 23 is designated as the seventeenth intersection (reference number 117). There are two intersections between the inner peripheral wall of the fifth through hole 25 and the fourth reference line 44, and the intersection farther from the fourth through hole 24 is designated as the eighth intersection (reference number 108). The intersection closer to the fourth through hole 24 is designated as the eighteenth intersection (reference number 118).

[0040] The third through conductor 33 is inserted into the third through hole 23 and is located within the third through hole 23 on the side farthest from both the fourth through hole 24 and the fifth through hole 25. This is expressed as the third through conductor 33 being in contact with or close to the portion between the third intersection 103 and the fourth intersection 104. The third through conductor 33 is also spaced apart from the thirteenth intersection 113, which is the intersection closer to the fourth through hole 24, and is also spaced apart from the fourteenth intersection 114, which is the intersection closer to the fifth through hole 25. Figure 5 shows an aspect in which the third through conductor 33 is in contact with the inner circumferential wall of the third through hole 23 at its upper left end between the third intersection 103 and the fourth intersection 104.

[0041] The fourth through conductor 34 is inserted into the fourth through hole 24 and is located within the fourth through hole 24 on a side farther from both the fifth through hole 25 and the third through hole 23. This is expressed as the fourth through conductor 34 being in contact with or close to a portion between the fifth intersection 105 and the sixth intersection 106. The fourth through conductor 34 is also spaced apart from the fifteenth intersection 115, which is the intersection closer to the fifth through hole 25, and is also spaced apart from the sixteenth intersection 116, which is the intersection closer to the third through hole 23. Figure 5 shows an aspect in which the upper right end of the fourth through conductor 34 is in contact with the inner circumferential wall of the fourth through hole 24 between the fifth intersection 105 and the sixth intersection 106.

[0042] The fifth through conductor 35 is inserted into the fifth through hole 25 and is located within the fifth through hole 25 on a side farther from both the third through hole 23 and the fourth through hole 24. This is expressed as the fifth through conductor 35 being in contact with or close to a portion between the seventh intersection 107 and the eighth intersection 108. The fifth through conductor 35 is also spaced apart from the seventeenth intersection 117, which is the intersection closer to the third through hole 23, and is also spaced apart from the eighteenth intersection 118, which is the intersection closer to the fourth through hole 24. Figure 5 shows an aspect in which the fifth through conductor 35 is in contact with the inner circumferential wall of the fifth through hole 25 at its lower end between the seventh intersection 107 and the eighth intersection 108.

[0043] In this specification, with regard to "the through conductor contacts or is close to the portion between the intersections," "the portion between the intersections" refers to the portion of the inner peripheral wall of the through hole that is between the intersections and is the portion that connects the intersections by the shortest distance along the inner peripheral wall. When the through conductor contacts this portion, it is in a form where "the through conductor contacts the portion between the intersections," and it is visually determined whether the positional relationship of the through conductor in contact with the portion between the intersections is such that it is in contact with the portion between the intersections when viewed from above.

[0044] A case where a through conductor is close to a portion between intersections will be described with reference to FIG. 6 . FIG. 6 is an explanatory diagram illustrating the positional relationship when a through conductor is close to a portion between intersections, and shows the relationship between the third through conductor 33, the third through hole 23, and the third intersection 103 and fourth intersection 104. First, focus on the point where the side surface (outer periphery) of the third through conductor 33 is closest to the inner peripheral wall of the third through hole 23, and measure this distance, i.e., the shortest distance between the third through conductor 33 and the inner peripheral wall 26 of the third through hole 23 (indicated by a double-headed arrow R1 in FIG. 6 ). A point on the side surface of the third through conductor 33 is designated as the closest point 33r. Separately, a sector is drawn with the center C3 of the third through hole 23 as its center and the third intersection 103 and the fourth intersection 104 as its two ends. If the nearest point 33 r is within the sector, it can be said that the third through conductor 33 is located on the farthest side from both the fourth through hole 24 and the fifth through hole 25 within the third through hole 23 .

[0045] Furthermore, to determine that the third through conductor 33 is close to the portion between the third intersection 103 and the fourth intersection 104, the shortest distance between the third through conductor 33 and the inner peripheral wall 26 of the third through hole 23 (indicated by a double-headed arrow R1 in FIG. 6 ) must be relatively short, and it is preferable that the shortest distance R1 be 20 μm or less. Furthermore, as an indicator indicating that the shortest distance between the third through conductor 33 and the inner peripheral wall 26 of the third through hole 23 is relatively short, the proximity rate can be expressed as [(R2-R1) / (R1+R2)]×100(%), where R2 (indicated by a double-headed arrow R2 in FIG. 6 ) is the longest distance between the third through conductor 33 and the inner peripheral wall 26 of the third through hole 23. It is preferable that this proximity rate be 50% or greater. Furthermore, a proximity rate of 70% or greater is more preferable, and a proximity rate of 90% or greater is even more preferable. The same applies to the relationships between the fourth through hole and the fourth through conductor, and between the fifth through hole and the fifth through conductor.

[0046] As in the embodiment focusing on two specific through holes described above, in the embodiment focusing on three specific through holes, when an outward stress is applied to the through conductors inserted in the through holes, the through conductors are prevented from deforming the substrate and moving in the planar direction of the substrate, thereby making it possible to provide a substrate with built-in through conductors in which the through conductors inserted in the through holes are prevented from moving due to thermal stress.

[0047] Next, an example of the positional relationship of the through holes and the through conductors with respect to the metal layer will be described. First, an embodiment focusing on two specific through holes among the through holes into which the through conductors are inserted will be described. In the through conductor-embedded substrate of the present invention, the metal layer may have a longitudinal direction, and the first reference line may extend along the longitudinal direction.

[0048] 7 is a top view showing the positional relationship between two through holes and through conductors of interest and the metal layer, in which the through holes and through conductors are shown together with the metal layer with the metal layer being transparent in order to show the positional relationship between the through holes and through conductors and the metal layer.

[0049] FIG. 7 shows a metal layer 71 on the first main surface of the substrate, a first through hole 21, a first through conductor 31 inserted into the first through hole 21, and a second through hole 22, a second through conductor 32 inserted into the second through hole 22. A first reference line 41 is also shown. The metal layer 71 has a rectangular shape in top view and has a longitudinal direction. The longitudinal direction is along the long side of the rectangle, and is indicated by a double-headed arrow L in FIG. 7. In the embodiment shown in FIG. 7, the first reference line 41 is along the longitudinal direction L of the metal layer 71. In this specification, "the reference line is along the longitudinal direction" means that the reference line is parallel to the longitudinal direction or slightly deviated from parallelism. If the angle (acute angle) between the reference line and the longitudinal direction is 5° or less, the reference line is considered to be along the longitudinal direction.

[0050] The longitudinal direction of the metal layer is the direction in which the force tending to move the through conductor inserted in two through holes of interest becomes stronger when thermal stress is applied to them. When focusing on the first through hole 21, if the first reference line 41 is aligned with the longitudinal direction L of the metal layer 71, it can be said that the first through hole 21, the first through conductor 31, the first intersection 101, and the eleventh intersection 111 are also aligned with the longitudinal direction L of the metal layer 71. The fact that the first through conductor 31 tends to move along the longitudinal direction of the metal layer 71 in response to thermal stress can be said to mean that the first through conductor tends to move along the first reference line 41 toward the first intersection 101. In the substrate with built-in through conductors of the present invention, the first through conductor 31 is in contact with or close to the first intersection 101, and therefore movement of the first through conductor 31 in this direction is suppressed. From the above, since the metal layer has a longitudinal direction and the first reference line extends in the longitudinal direction, the direction in which the through conductor tends to move due to thermal stress applied to the through conductor-embedded substrate coincides with the direction in which the movement of the through conductor due to thermal stress can be effectively prevented, and therefore the through conductor inserted into the through hole can be more effectively prevented from moving due to thermal stress.

[0051] Furthermore, the two through holes and through conductors of interest are preferably located near both ends along the longitudinal direction of the metal layer. This positional relationship allows the effects of the configuration of the through conductor-embedded substrate of the present invention to be more effectively achieved. That is, when a sixth reference line is defined as a line starting from the center of gravity of the metal layer, passing through the center of the first through hole, and reaching the end of the metal layer, the center of the first through hole is preferably located in a region on the sixth reference line closer to the end of the metal layer than the center of gravity of the metal layer. When a seventh reference line is defined as a line starting from the center of gravity of the metal layer, passing through the center of the second through hole, and reaching the end of the metal layer, the center of the second through hole is preferably located in a region on the seventh reference line closer to the end of the metal layer than the center of gravity of the metal layer. In this specification, the center of gravity of the metal layer is defined as the center of gravity of a flat plate (the smallest rectangle defined to include all the wiring that constitutes the metal layer) with the outer edges of the metal layer removed.

[0052] 8 is a top view showing the positional relationship between two through holes and through conductors of interest and the metal layer. It is a diagram showing the same positional relationship as in FIG. 7 , but the illustration of the reference lines has been changed from that in FIG. 8 . In FIG. 8 , a sixth reference line 46 is shown, which is a straight line that starts at the center of gravity G of the metal layer 71, passes through the center C1 of the first through hole 21, and reaches an end 76 of the metal layer. Also shown is a seventh reference line 47, which is a straight line that starts at the center of gravity G of the metal layer 71, passes through the center C2 of the second through hole 22, and reaches an end 77 of the metal layer.

[0053] The center C1 of the first through hole 21 is located on the sixth reference line 46 in a region closer to the end 76 of the metal layer 71 than the center of gravity G of the metal layer 71. This means that when the region is divided into the center of gravity G side and the end 76 side with the midpoint M6 of the sixth reference line 46 as the boundary point, the center C1 of the first through hole 21 is located in the region closer to the end 76 side. Similarly, the center C2 of the second through hole 22 is located on the seventh reference line 47 in a region closer to the end 77 of the metal layer 71 than the center of gravity G of the metal layer 71. This means that when the region is divided into the center of gravity G side and the end 77 side with the midpoint M7 of the seventh reference line 47 as the boundary point, the center C2 of the second through hole 22 is located in the region closer to the end 77 side.

[0054] The effect of the configuration of the through conductor-embedded substrate of the present invention is more effectively exhibited when the two through holes and through conductors of interest are located near both ends along the longitudinal direction of the metal layer. Therefore, the effect of the present invention is more effectively exhibited by positioning the first through hole 21 in the region closer to the end 76 and the second through hole 22 in the region closer to the end 77, as defined above.

[0055] Next, as an example of the positional relationship of the through holes and the through conductors with respect to the metal layer, an embodiment will be described in which attention is focused on three specific through holes among the through holes into which the through conductors have been inserted. When focusing on three specific through holes, it is preferable that all three through holes are located near the end of the metal layer. With this positional relationship, the effects of the configuration of the through conductor-embedded substrate of the present invention can be more effectively exhibited. That is, when the eighth reference line is a straight line starting from the center of gravity of the metal layer, passing through the center of the third through hole, and reaching the end of the metal layer, the center of the third through hole is located in a region on the eighth reference line that is closer to the end of the metal layer than the center of gravity of the metal layer; when the ninth reference line is a straight line starting from the center of gravity of the metal layer, passing through the center of the fourth through hole, and reaching the end of the metal layer, the center of the fourth through hole is located in a region on the ninth reference line that is closer to the end of the metal layer than the center of gravity of the metal layer; and when the tenth reference line is a straight line starting from the center of gravity of the metal layer, passing through the center of the fifth through hole, and reaching the end of the metal layer, the center of the fifth through hole is located in a region on the tenth reference line that is closer to the end of the metal layer than the center of gravity of the metal layer.

[0056] 9 is a top view showing the positional relationship between the three through holes and through conductors of interest and the metal layer. Fig. 9 also shows an eighth reference line 48, which is a straight line that starts at the center of gravity G of the metal layer 71, passes through the center C3 of the third through hole 23, and reaches an end 78 of the metal layer. Fig. 9 also shows a ninth reference line 49, which is a straight line that passes through the center of gravity G of the metal layer 71 and the center C4 of the fourth through hole 24, and reaches an end 79 of the metal layer. Fig. 9 also shows a tenth reference line 50, which is a straight line that passes through the center of gravity G of the metal layer 71 and the center C5 of the fifth through hole 25, and reaches an end 80 of the metal layer.

[0057] The center C3 of the third through hole 23 is located on the eighth reference line 48 in a region closer to the end 78 of the metal layer 71 than the center of gravity G of the metal layer 71. This means that when the region is divided into the center of gravity G side and the end 78 side with the midpoint M8 of the eighth reference line 48 as the boundary point, the center C3 of the third through hole 23 is located in the region on the end 78 side. Similarly, the center C4 of the fourth through hole 24 is located on the ninth reference line 49 in a region closer to the end 79 of the metal layer 71 than the center of gravity G of the metal layer 71. This means that when the region is divided into the center of gravity G side and the end 79 side with the midpoint M9 of the ninth reference line 49 as the boundary point, the center C4 of the fourth through hole 24 is located in the region on the end 79 side. Similarly, the center C5 of the fifth through hole 25 is located on the tenth reference line 50 in a region closer to the end 80 of the metal layer 71 than the center of gravity G of the metal layer 71. This means that when the midpoint M10 of the 10th reference line 50 is used as the boundary point and the area is divided into the area on the center of gravity G side and the area on the end 80 side, the center C5 of the fifth through hole 25 is located in the area on the end 80 side.

[0058] The effect of the configuration of the through conductor-embedded substrate of the present invention is more effectively exhibited when the three through holes and through conductors of interest are located near the ends of the metal layer. Therefore, the effect of the present invention is more effectively exhibited when the third through hole 23 is located in the region closer to the end 78, the fourth through hole 24 is located in the region closer to the end 79, and the fifth through hole 25 is located in the region closer to the end 80, as defined above.

[0059] Next, an example of the positional relationship of the through holes and the through conductors with respect to the metal layer in a cross section in the thickness direction will be described. In the substrate with built-in through conductors of the present invention, in a cross section in the thickness direction along the direction connecting the first main surface and the second main surface of the substrate, at least one of the through conductors may be in line contact with the inner peripheral wall of the through hole into which the through conductor is inserted.

[0060] FIG. 10 is a cross-sectional view schematically illustrating a state in which the through conductor is in line contact with the inner wall of the through hole into which it is inserted. The cross-sectional view shown in FIG. 10 is a thickness direction cross-sectional view along the direction connecting the first main surface 11 and the second main surface 12 of the substrate 10. The through conductor 30 is inserted into the through hole 20, and the side of the through conductor 30 is in contact with a line representing the inner wall 26 of the through hole 20 so that the side of the through conductor 30 coincides with the line representing the inner wall 26 of the through hole 20. This constitutes line contact. Because the top view shapes of the through hole 20 and the through conductor 30 are both circular but have different diameters, when the through hole 20 and the through conductor 30 come into contact, the contact is in line contact rather than surface contact. When the through conductor 30 is in line contact with the inner wall 26 of the through hole 20, the effect of preventing the through conductor 30 inserted into the through hole 20 from moving due to thermal stress is more effectively exhibited. Note that, of the multiple through holes and through conductors provided in the through conductor-embedded substrate, all of the through holes may be in line contact with the inner wall of the through conductor, or only some of the through holes may be in line contact with the inner wall of the through conductor.

[0061] Furthermore, in the substrate with built-in through conductors of the present invention, in a thickness cross section along the direction connecting the first main surface and the second main surface of the substrate, at least one of the through conductors may have a length along the thickness direction of the through conductor that is shorter than the length along the thickness direction of the through hole into which the through conductor is inserted, and may be in contact with or close to the inner wall of the through hole into which the through conductor is inserted at a position spaced from the thickness direction end of the through hole.

[0062] FIG. 11 is a cross-sectional view schematically illustrating a configuration in which the length of the through conductor is shorter than the length of the through hole. The cross-sectional view shown in FIG. 11 is a thickness-direction cross-sectional view along a direction connecting the first main surface 11 and the second main surface 12 of the substrate 10. The through conductor 30 is inserted into the through hole 20, and the length of the through conductor 30 along the thickness direction is shorter than the length of the through hole 20 along the thickness direction. Therefore, the metal layer 71 enters the through hole 20 so as to contact the upper surface 36 of the through conductor 30. The through conductor 30 contacts the inner peripheral wall 26 of the through hole 20 at a contact point 37 located away from the end 27 of the through hole 20 in the thickness direction. The side surface of the through conductor 30 is not parallel to the inner peripheral wall of the through hole 20, and the through conductor 30 can be said to be tilted within the through hole 20. Even in this configuration, the through conductor 30 is in contact with the inner wall 26 of the through hole 20, which is the surface of the substrate 10, at the contact point 37, thereby preventing the through conductor 30 inserted into the through hole 20 from moving due to thermal stress.

[0063] Furthermore, the through conductor may be close to the inner peripheral wall of the through hole into which the through conductor is inserted, at a position spaced from the end of the through hole in the thickness direction. The proximity of the inner peripheral wall and the through conductor is defined as above, and it is possible to determine whether the inner peripheral wall and the through conductor are close to each other by determining the shortest distance between the through conductor and the inner peripheral wall of the through hole, using the point at which the distance between the tilted through conductor and the inner peripheral wall of the through hole in a cross section in the thickness direction is shortest as the closest point.

[0064] Of the plurality of through holes and through conductors provided in the through conductor-embedded substrate, the length along the thickness direction of all of the through conductors may be shorter than the length along the thickness direction of the through hole into which the through conductor is inserted, and the through conductor may be in contact with or close to the inner circumferential wall of the through hole into which the through conductor is inserted at a position spaced apart from the end of the through hole in the thickness direction. Also, the length along the thickness direction of some of the through conductors may be shorter than the length along the thickness direction of the through hole into which the through conductor is inserted, and the through conductor may be in contact with or close to the inner circumferential wall of the through hole into which the through conductor is inserted at a position spaced apart from the end of the through hole in the thickness direction.

[0065] Next, examples of the surface state of the through hole and the through conductor in a cross section in the thickness direction will be described. In the substrate with built-in through conductors of the present invention, the side surfaces of the through conductors may be provided with irregularities. Furthermore, the irregularities provided on the through conductors may have a surface roughness Ra of 1 μm or more.

[0066] FIG. 12 is a cross-sectional view schematically illustrating an embodiment in which unevenness is provided on the side surface of a through conductor. FIG. 12 illustrates an embodiment in which unevenness 38 is provided on the side surface of a through conductor 30. When unevenness 38 is provided on the side surface of the through conductor 30, an anchor effect occurs at the contact surface between the through conductor 30 and the surrounding resin 60, strengthening the bond between the through conductor 30 and the resin 60 and preventing a failure mode in which the through conductor 30 comes off the resin 60. The unevenness 38 on the side surface of the through conductor 30 may be provided on the entire side surface of the through conductor 30, or may be provided on only a portion of the side surface. Furthermore, the size of the unevenness 38 on the side surface of the through conductor 30 may be 1 μm or more in terms of surface roughness Ra. Alternatively, the surface roughness Ra may be 10 μm or less. The surface roughness can be measured by taking a cross-sectional photograph including the side surface of the through conductor and analyzing the image.

[0067] In the substrate with built-in through conductors of the present invention, the inner peripheral wall of the through hole may be provided with irregularities. The irregularities provided on the inner peripheral wall of the through hole may have a surface roughness Ra of 1 μm or more.

[0068] FIG. 13 is a cross-sectional view schematically illustrating an embodiment in which the inner peripheral wall of a through hole is provided with irregularities. FIG. 13 illustrates an embodiment in which irregularities 28 are provided on the inner peripheral wall 26 of a through hole 20. Providing the irregularities 28 on the inner peripheral wall 26 of the through hole 20 creates an anchor effect at the contact surface with the resin 60 inside the through hole 20, strengthening the bond between the inner peripheral wall 26 of the through hole 20 and the resin 60, preventing a failure mode in which the resin 60 slips out of the through hole 20 and the through conductor 30 slips out along with the resin 60. The irregularities 28 on the inner peripheral wall 26 of the through hole 20 may be provided on the entire inner peripheral wall 26 of the through hole 20, or may be provided on only a portion of the inner peripheral wall 26. Furthermore, the size of the irregularities 28 on the inner peripheral wall 26 of the through hole 20 may be 1 μm or more in terms of surface roughness Ra. Furthermore, the surface roughness Ra may be 50 μm or less. Surface roughness measurement can be performed by taking a cross-sectional photograph including the inner peripheral wall of the through hole and analyzing the image.

[0069] Alternatively, the through conductor may have an uneven surface on its side surface, and the through hole may also have an uneven surface on its inner wall. Having uneven surfaces on both surfaces strengthens the bond between the resin and both the through conductor and the inner wall of the through hole, which is preferable. The uneven surfaces may have the same size or different sizes.

[0070] Methods for providing irregularities on the side surface of the through conductor or the inner wall of the through hole include physical processing such as cutting and sandblasting, and chemical processing such as etching, but the method is not limited thereto.

[0071] Although the method for manufacturing the substrate with built-in through conductors of the present invention is not particularly limited, it can be manufactured by preparing a substrate with a plurality of through holes, inserting the through conductors into the through holes, filling the spaces within the through holes with resin, and providing metal layers by plating on the first and second main surfaces of the substrate. In this process, the mounting position of the component mounting machine can be shifted from the center of the through hole to mount the components (mount the through conductors), thereby producing the substrate with built-in through conductors of the present invention.

[0072] The present specification discloses the following:

[0073] <1> A substrate comprising: a first main surface and a second main surface opposite to the first main surface, and having a plurality of through holes extending from the first main surface along the second main surface; through conductors inserted into the through holes; and a metal layer extending in the same planar direction as the first main surface and connected to the through conductors, wherein the through holes comprise a first through hole and a second through hole that are different through holes, the through conductors comprise a first through conductor inserted into the first through hole and a second through conductor inserted into the second through hole, and both the first through conductor and the second through conductor are connected to the metal layer, and when a straight line passing through the center of the first through hole and the center of the second through hole is defined as a first reference line, the first through conductor is in contact with or close to a first intersection point that is an intersection point farther from the second through hole than an inner circumferential wall of the first through hole and the first reference line, A substrate with built-in through conductors, characterized in that the second through conductor is in contact with or close to a second intersection point, which is the intersection point between the inner wall of the second through hole and the first reference line and is on the farther side from the first through hole.

[0074] <2> A substrate comprising: a first main surface and a second main surface opposite to the first main surface, and having a plurality of through holes extending from the first main surface along the second main surface; through conductors inserted in the through holes; and a metal layer extending in the same planar direction as the first main surface and connected to the through conductors, wherein the through holes comprise third through holes, fourth through holes, and fifth through holes which are different through holes; the through conductors comprise a third through hole, a fourth through hole inserted in the third through hole, and a fifth through hole inserted in the fifth through hole, wherein the third through conductor, the fourth through hole, and the fifth through conductor are all connected to the metal layer; and when a line passing through the center of the third through hole and the center of the fourth through hole is defined as a third reference line, a line passing through the center of the fourth through hole and the center of the fifth through hole is defined as a fourth reference line, and a line passing through the center of the fifth through hole and the center of the third through hole is defined as a fifth reference line, the third through conductor is in contact with or close to a portion between a third intersection, which is an intersection between the inner wall of the third through hole and the third reference line and is located farther from the fourth through hole, and a fourth intersection, which is an intersection between the inner wall of the third through hole and the fifth reference line and is located farther from the fifth through hole; the fourth through conductor is in contact with or close to a portion between a fifth intersection, which is an intersection between the inner wall of the fourth through hole and the fourth reference line and is located farther from the fifth through hole, and a sixth intersection, which is an intersection between the inner wall of the fourth through hole and the third reference line and is located farther from the third through hole; and the fifth through conductor is in contact with or close to a portion between a seventh intersection, which is an intersection between the inner wall of the fifth through hole and the fifth reference line and is located farther from the third through hole, and an eighth intersection, which is an intersection between the inner wall of the fifth through hole and the fourth reference line and is located farther from the fourth through hole.

[0075] <3> The substrate with built-in through conductors according to <1>, wherein the metal layer has a longitudinal direction, and the first reference line extends along the longitudinal direction.

[0076] <4> The substrate with built-in through conductors according to <1> or <3>, wherein when a sixth reference line is defined as a straight line starting from the center of gravity of the metal layer, passing through the center of the first through hole, and reaching an end of the metal layer, the center of the first through hole is located in a region on the sixth reference line that is closer to the end of the metal layer than the center of gravity of the metal layer; and when a seventh reference line is defined as a straight line starting from the center of gravity of the metal layer, passing through the center of the second through hole, and reaching an end of the metal layer, the center of the second through hole is located in a region on the seventh reference line that is closer to the end of the metal layer than the center of gravity of the metal layer.

[0077] <5> The substrate with built-in through conductors according to <2>, wherein when a straight line starting from the center of gravity of the metal layer, passing through the center of the third through hole, and reaching an end of the metal layer is defined as an eighth reference line, the center of the third through hole is located in a region on the eighth reference line that is closer to the end of the metal layer than the center of gravity of the metal layer; when a straight line starting from the center of gravity of the metal layer, passing through the center of the fourth through hole, and reaching an end of the metal layer is defined as a ninth reference line, the center of the fourth through hole is located in a region on the ninth reference line that is closer to the end of the metal layer than the center of gravity of the metal layer; and when a straight line starting from the center of gravity of the metal layer, passing through the center of the fifth through hole, and reaching an end of the metal layer is defined as a tenth reference line, the center of the fifth through hole is located in a region on the tenth reference line that is closer to the end of the metal layer than the center of gravity of the metal layer.

[0078] <6> The substrate with built-in through conductors according to any one of <1> to <5>, wherein, in a thickness direction cross section along a direction connecting the first main surface and the second main surface of the substrate, at least one of the through conductors is in line contact with an inner peripheral wall of the through hole into which the through conductor is inserted.

[0079] <7> The substrate with built-in through conductors according to any one of <1> to <6>, wherein, in a thickness direction cross section along a direction connecting the first main surface and the second main surface of the substrate, the length of at least one of the through conductors along the thickness direction of the through conductor is shorter than the length along the thickness direction of the through hole into which the through conductor is inserted, and the through conductor is in contact with or close to the inner wall of the through hole into which the through conductor is inserted at a position spaced from the end of the through hole in the thickness direction.

[0080] <8> The substrate with built-in through conductors according to any one of <1> to <7>, wherein 30 or more through conductors are connected to one metal layer, and the percentage of the through conductors connected to the metal layer in which the centers of the through holes into which the through conductors are inserted are misaligned from the centers of the through conductors is 10% or more.

[0081] <9> The substrate with built-in through conductors according to any one of <1> to <8>, wherein a resin is filled between the through conductors and the through holes into which the through conductors are inserted.

[0082] <10> The substrate with built-in through conductors according to <9>, wherein the resin is an epoxy resin, a silicone resin, an acrylic resin, or a polyimide resin.

[0083] <11> The substrate with built-in through conductors according to any one of <1> to <10>, wherein the through conductors have unevenness on their side surfaces.

[0084] <12> The substrate with built-in through conductors according to <11>, wherein the irregularities provided on the through conductors have a surface roughness Ra of 1 μm or more.

[0085] <13> The substrate with built-in through conductors according to any one of <1> to <12>, wherein the inner peripheral wall of the through hole is provided with irregularities.

[0086] <14> The substrate with built-in through conductors according to any one of <1> to <13>, wherein the through conductors are made of a metal material.

[0087] <15> The substrate with built-in through conductors according to any one of <1> to <14>, wherein the substrate is a glass substrate.

[0088] REFERENCE SIGNS LIST 1 Substrate with built-in through conductor 10 Substrate 11 First main surface 12 Second main surface 20 Through hole 21 First through hole 22 Second through hole 23 Third through hole 24 Fourth through hole 25 Fifth through hole 26 Inner peripheral wall of through hole 27 End of through hole in thickness direction 28 Irregularities on inner peripheral wall of through hole 30 Through conductor 31 First through conductor 31r Closest point of first through conductor 32 Second through conductor 33 Third through conductor 33r Closest point of third through conductor 34 Fourth through conductor 35 Fifth through conductor 36 Top surface of through conductor 37 Contact point of through conductor 38 Irregularities on side surface of through conductor 41 First reference line 43 Third reference line 44 Fourth reference line 45 Fifth reference line 46 Sixth reference line 47 Seventh reference line 48 Eighth reference line 49 Ninth reference line 50 Tenth reference line 60 Resin 70 Metal layer 71 Metal layer on the first main surface side of the substrate 72 Metal layer on the second main surface side of the substrate 76, 77, 78, 79, 80 Ends of metal layer 101 First intersection 102 Second intersection 103 Third intersection 104 Fourth intersection 105 Fifth intersection 106 Sixth intersection 107 Seventh intersection 108 Eighth intersection 111 Eleventh intersection 112 Twelfth intersection 113 Thirteenth intersection 114 Fourteenth intersection 115 Fifteenth intersection 116 Sixteenth intersection 117 Seventeenth intersection 118 Eighteenth intersection 120 Uninterested through hole 130 Uninterested through conductor C1 Center of first through hole C2 Center of second through hole C3 Center of third through hole C4 Center of the fourth through hole C5 Center of the fifth through hole G Center of gravity of the metal layer R1 Shortest distance between the through conductor and the inner wall of the through hole R2 Longest distance between the through conductor and the inner wall of the through hole M6, M7, M8, M9, M10 Midpoint

Claims

1. A substrate comprising: a first main surface and a second main surface opposite to the first main surface, the substrate having a plurality of through holes extending from the first main surface along the second main surface; a through conductor inserted into the through hole; and a metal layer extending in the same planar direction as the first main surface and connected to the through conductor, the through holes comprising a first through hole and a second through hole which are different through holes, the through conductor comprising a first through conductor inserted into the first through hole and a second through conductor inserted into the second through hole, the first through conductor and the second through conductor are both connected to the metal layer, and when a straight line passing through a center of the first through hole and a center of the second through hole is defined as a first reference line, the first through conductor is in contact with or close to a first intersection which is an intersection farther from the second through hole than an intersection between an inner circumferential wall of the first through hole and the first reference line, A substrate with built-in through conductors, characterized in that the second through conductor is in contact with or close to a second intersection between the inner wall of the second through hole and the first reference line, which is the intersection farther from the first through hole.

2. A substrate comprising: a first main surface and a second main surface opposite to the first main surface, the substrate having a plurality of through holes extending from the first main surface along the second main surface; a through conductor inserted into the through hole; and a metal layer extending in the same planar direction as the first main surface and connected to the through conductor, the through holes comprising a third through hole, a fourth through hole, and a fifth through hole which are different through holes, the through conductor comprising a third through hole inserted into the third through hole, a fourth through hole inserted into the fourth through hole, and a fifth through hole inserted into the fifth through hole, the third through hole, the fourth through hole, and the fifth through hole are all connected to the metal layer, when a straight line passing through the center of the third through hole and the center of the fourth through hole is defined as a third reference line, a straight line passing through the center of the fourth through hole and the center of the fifth through hole is defined as a fourth reference line, and a straight line passing through the center of the fifth through hole and the center of the third through hole is defined as a fifth reference line, the third through conductor is in contact with or close to a portion between a third intersection, which is an intersection point farther from the fourth through hole among the intersections of an inner wall of the third through hole and the third reference line, and a fourth intersection, which is an intersection point farther from the fifth through hole among the intersections of an inner wall of the third through hole and the fifth reference line; the fourth through conductor is in contact with or close to a portion between a fifth intersection, which is an intersection point farther from the fifth through hole among the intersections of an inner wall of the fourth through hole and the fourth reference line, and a sixth intersection, which is an intersection point farther from the third through hole among the intersections of an inner wall of the fourth through hole and the third reference line; and the fifth through conductor is in contact with or close to a portion between a seventh intersection, which is an intersection point farther from the third through hole among the intersections of an inner wall of the fifth through hole and the fifth reference line, and an eighth intersection, which is an intersection point farther from the fourth through hole among the intersections of an inner wall of the fifth through hole and the fourth reference line.

3. The substrate with built-in through conductors according to claim 1, wherein the metal layer has a longitudinal direction, and the first reference line extends along the longitudinal direction.

4. A substrate with built-in through conductor as described in claim 1 or 3, wherein when a straight line starting from the center of gravity of the metal layer, passing through the center of the first through hole and reaching an end of the metal layer is defined as a sixth reference line, the center of the first through hole is located in a region on the sixth reference line that is closer to the end of the metal layer than the center of gravity of the metal layer, and when a straight line starting from the center of gravity of the metal layer, passing through the center of the second through hole and reaching an end of the metal layer is defined as a seventh reference line, the center of the second through hole is located in a region on the seventh reference line that is closer to the end of the metal layer than the center of gravity of the metal layer.

5. The substrate with built-in through conductor according to claim 2, wherein when a straight line starting from the center of gravity of the metal layer, passing through the center of the third through hole and reaching an end of the metal layer is defined as an eighth reference line, the center of the third through hole is located in a region on the eighth reference line that is closer to the end of the metal layer than the center of gravity of the metal layer; when a straight line starting from the center of gravity of the metal layer, passing through the center of the fourth through hole and reaching an end of the metal layer is defined as a ninth reference line, the center of the fourth through hole is located in a region on the ninth reference line that is closer to the end of the metal layer than the center of gravity of the metal layer; and when a straight line starting from the center of gravity of the metal layer, passing through the center of the fifth through hole and reaching the end of the metal layer is defined as a tenth reference line, the center of the fifth through hole is located in a region on the tenth reference line that is closer to the end of the metal layer than the center of gravity of the metal layer.

6. A substrate with built-in through conductors as described in any one of claims 1 to 5, wherein, in a thickness direction cross section along a direction connecting the first main surface and the second main surface of the substrate, at least one of the through conductors is in line contact with an inner peripheral wall of the through hole into which the through conductor is inserted.

7. A substrate with built-in through conductors as described in any one of claims 1 to 6, wherein, in a thickness direction cross section along a direction connecting the first main surface and the second main surface of the substrate, the length of at least one of the through conductors along the thickness direction is shorter than the length along the thickness direction of the through hole into which the through conductor is inserted, and the through conductor is in contact with or in close proximity to the inner wall of the through hole into which the through conductor is inserted at a position spaced from the end of the through hole in the thickness direction.

8. A substrate with built-in through conductors as described in any one of claims 1 to 7, wherein 30 or more through conductors are connected to one metal layer, and the percentage of through conductors connected to the metal layer in which the center of the through hole into which the through conductor is inserted is misaligned with the center of the through conductor is 10% or more.

9. The substrate with built-in through conductors according to any one of claims 1 to 8, wherein the space between the through conductors and the through holes into which the through conductors are inserted is filled with resin.

10. The substrate with built-in through conductors according to claim 9, wherein the resin is an epoxy resin, a silicone resin, an acrylic resin or a polyimide resin.

11. The substrate with built-in through conductors according to any one of claims 1 to 10, wherein the side surfaces of the through conductors are provided with irregularities.

12. The substrate with built-in through conductors according to claim 11, wherein the irregularities provided on the through conductors have a surface roughness Ra of 1 μm or more.

13. The substrate with built-in through conductors according to any one of claims 1 to 12, wherein the inner peripheral wall of the through hole is provided with projections and recesses.

14. The substrate with built-in through conductors according to any one of claims 1 to 13, wherein the through conductors are made of a metallic material.

15. The substrate with built-in through conductors according to any one of claims 1 to 14, wherein the substrate is a glass substrate.

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