Metal layer embedded substrate

Abstract

A metal layer embedded substrate 1 includes: a core part 10 having a first main surface 10a and a second main surface 10b facing each other in a thickness direction and including a metal layer 20; a first insulating layer 60A provided on the first main surface 10a of the core part 10; a second insulating layer 60B provided on the second main surface 10b of the core part 10; and a through conductor 70 provided at least on an inner wall surface of a through hole 71 penetrating the core part 10, the first insulating layer 60A, and the second insulating layer 60B in the thickness direction. In the through hole 71, a diameter P of a portion penetrating the metal layer 20 is larger than a diameter Q of a portion penetrating the first insulating layer 60A and a diameter R of a portion penetrating the second insulating layer 60B.

Description

Metal layer embedded substrate

[0001] The present invention relates to a metal layer embedded substrate.

[0002] Patent Document 1 discloses a solid electrolytic capacitor built-in substrate in which a sheet-like solid electrolytic capacitor having an aluminum metal layer with a porous part as an anode and a layer of silver paste as a cathode is incorporated in an insulating resin.

[0003] Japanese Patent Application Laid-Open No. 2007-251101

[0004] In the solid electrolytic capacitor built-in substrate described in Patent Document 1, as shown in FIG. 1 of Patent Document 1 and the like, the aluminum metal layer as the anode is embedded in the insulating resin, and further, through holes penetrating the aluminum metal layer and the insulating resin are provided. Thereby, in the solid electrolytic capacitor built-in substrate described in Patent Document 1, even when the aluminum metal layer is in a state of being embedded in the insulating resin, it is drawn out to the outside of the insulating resin through the through holes.

[0005] However, the solid electrolytic capacitor built-in substrate described in Patent Document 1 has the following problems.

[0006] First, there is a first problem that the heat dissipation property related to dissipating the heat generated in the solid electrolytic capacitor to the outside of the insulating resin is insufficient in the solid electrolytic capacitor built-in substrate described in Patent Document 1.

[0007] In the solid electrolytic capacitor-embedded substrate described in Patent Document 1, the aluminum metal layer is drawn out to the outside of the insulating resin through through-holes, so it is thought that the heat generated by the solid electrolytic capacitor including the aluminum metal layer is dissipated to the outside of the insulating resin through the through-holes. On the other hand, with the miniaturization of electronic products in recent years, it is conceivable to try to miniaturize the solid electrolytic capacitor-embedded substrate described in Patent Document 1, which can be used in electronic products. To miniaturize the solid electrolytic capacitor-embedded substrate described in Patent Document 1, for example, one could try to reduce the size of the through-holes, specifically by reducing the diameter of the through-holes. However, in the solid electrolytic capacitor-embedded substrate described in Patent Document 1, if the diameter of the through-holes is reduced, the volume of the through-holes provided in the through-holes may become insufficient to dissipate the heat generated by the solid electrolytic capacitor to the outside of the insulating resin. Thus, in the solid electrolytic capacitor-embedded substrate described in Patent Document 1, for example, if the diameter of the through-holes is reduced, the heat dissipation related to dissipating the heat generated by the solid electrolytic capacitor to the outside of the insulating resin may become insufficient.

[0008] Furthermore, the substrate with a built-in solid electrolytic capacitor described in Patent Document 1 has a second problem: it has insufficient resistance to delamination between layers other than the aluminum metal layer and the through-holes.

[0009] In the solid electrolytic capacitor-embedded substrate described in Patent Document 1, as shown in Figure 1 of Patent Document 1, an insulating resin layer other than the aluminum metal layer is in contact with the through-holes. In the solid electrolytic capacitor-embedded substrate described in Patent Document 1, as shown in Figure 1 of Patent Document 1, the through-holes are linear, so there is a limit to how much the contact area between the insulating resin and the through-holes can be increased. Thus, in the solid electrolytic capacitor-embedded substrate described in Patent Document 1, there is a limit to how much the contact area between the insulating resin and the through-holes can be increased, and as a result, there is a risk that the peel resistance between the insulating resin and the through-holes will be insufficient.

[0010] As described above, the solid electrolytic capacitor-embedded substrate described in Patent Document 1 has two problems: firstly, insufficient heat dissipation related to dissipating the heat generated by the solid electrolytic capacitor to the outside of the insulating resin; and secondly, insufficient peel resistance between layers other than the aluminum metal layer and through-holes. These problems are not limited to the solid electrolytic capacitor-embedded substrate described in Patent Document 1, but are common to metal layer-embedded substrates in which a metal layer is embedded in an insulating layer, and through-conductors are provided in through-holes that penetrate the metal layer and the insulating layer.

[0011] The present invention was made to solve the above problems and aims to provide a metal layer embedded substrate that can improve both the heat dissipation to the outside of the insulating layer and the peel resistance between layers other than the metal layer and the through conductor.

[0012] The metal layer embedded substrate of the present invention comprises a core portion including a metal layer, having a first main surface and a second main surface opposite to each other in the thickness direction; a first insulating layer provided on the first main surface of the core portion; a second insulating layer provided on the second main surface of the core portion; and a through conductor provided on at least the inner wall surface of a through hole that penetrates the core portion, the first insulating layer, and the second insulating layer in the thickness direction, wherein the diameter of the portion of the through hole that penetrates the metal layer is larger than the diameter of the portion that penetrates the first insulating layer and the diameter of the portion that penetrates the second insulating layer.

[0013] According to the present invention, it is possible to provide a metal layer embedded substrate that can improve both the heat dissipation properties of the insulating layer to the outside and the peeling resistance between layers other than the metal layer and the through-conductor.

[0014] Figure 1 is a schematic cross-sectional view showing an example of a metal layer embedded substrate of the present invention. Figure 2 is a schematic cross-sectional view showing another example of the through-hole in Figure 1. Figure 3 is a schematic cross-sectional view showing another example of the through-hole in Figure 1, different from that of Figure 2. Figure 4 is a schematic cross-sectional view showing another example of the through-hole in Figure 1, different from that of Figures 2 and 3. Figure 5 is a schematic cross-sectional view showing a capacitor-embedded substrate, which is an embodiment of the metal layer embedded substrate shown in Figure 1. Figure 6 is a schematic cross-sectional view showing an example of the process of preparing the anode layer in the manufacturing method of the capacitor-embedded substrate shown in Figure 5. Figure 7 is a schematic cross-sectional view showing an example of the process of forming the dielectric layer in the manufacturing method of the capacitor-embedded substrate shown in Figure 5. Figure 8 is a schematic cross-sectional view showing an example of the process of forming the insulating mask layer in the manufacturing method of the capacitor-embedded substrate shown in Figure 5. Figure 9 is a schematic cross-sectional view showing an example of the process of forming the solid electrolyte layer in the manufacturing method of the capacitor-embedded substrate shown in Figure 5. Figure 10 is a schematic cross-sectional view illustrating an example of the process of forming a conductive layer in the method for manufacturing the capacitor-embedded substrate shown in Figure 5. Figure 11 is a schematic cross-sectional view illustrating an example of the process of forming through holes in the capacitor in the method for manufacturing the capacitor-embedded substrate shown in Figure 5. Figure 12 is a schematic cross-sectional view illustrating an example of the process of forming an insulating layer in the method for manufacturing the capacitor-embedded substrate shown in Figure 5. Figure 13 is a schematic cross-sectional view illustrating an example of the process of forming through holes in the capacitor and insulating layer in the method for manufacturing the capacitor-embedded substrate shown in Figure 5. Figure 14 is a schematic cross-sectional view illustrating an example of the process of partially widening the diameter of the through holes in the method for manufacturing the capacitor-embedded substrate shown in Figure 5. Figure 15 is a schematic cross-sectional view illustrating an example of the process of forming a through conductor in the method for manufacturing the capacitor-embedded substrate shown in Figure 5. Figure 16 is a schematic cross-sectional view illustrating an example of the process of forming a filling portion in the method for manufacturing the capacitor-embedded substrate shown in Figure 5. Figure 17 is a schematic cross-sectional view illustrating an example of the process of forming a conductive layer in the method for manufacturing the capacitor-embedded substrate shown in Figure 5. Figure 18 is a schematic cross-sectional view illustrating a modified example of the metal layer embedded substrate of the present invention. Figure 19 is a schematic cross-sectional view showing a capacitor-embedded substrate, which is an embodiment of the metal layer embedded substrate shown in Figure 18.Figure 20 is a schematic cross-sectional view showing a capacitor-embedded substrate, which is an embodiment of the metal layer embedded substrate shown in Figure 18, and is a different example from that shown in Figure 19.

[0015] The metal layer embedded substrate of the present invention will be described below. However, the present invention is not limited to the configuration described below, and may be modified as appropriate without departing from the spirit of the invention. Furthermore, a combination of several of the preferred configurations described below also constitutes the present invention.

[0016] The drawings shown below are schematic representations, and their dimensions, aspect ratios, and scales may differ from those of the actual product.

[0017] In this specification, unless otherwise specified, terms describing relationships between elements (e.g., "parallel," "perpendicular," etc.) and terms describing the shape of elements mean not only their literal, exact form, but also a range that is substantially equivalent, for example, a range that includes differences of a few percent.

[0018] [Metal Layer Embedded Substrate] The metal layer embedded substrate of the present invention comprises a core portion having a metal layer, having a first main surface and a second main surface opposite to each other in the thickness direction, a first insulating layer provided on the first main surface of the core portion, a second insulating layer provided on the second main surface of the core portion, and a through conductor provided on at least the inner wall surface of a through hole that penetrates the core portion, the first insulating layer, and the second insulating layer in the thickness direction, wherein the diameter of the portion of the through hole that penetrates the metal layer is larger than the diameter of the portion that penetrates the first insulating layer and the diameter of the portion that penetrates the second insulating layer.

[0019] In the metal layer embedded substrate of the present invention, the diameter of the portion of the through-hole that penetrates the metal layer is larger than the diameter of the portion that penetrates the first insulating layer and the diameter of the portion that penetrates the second insulating layer. As a result, the volume of the through-conductor provided in the through-hole tends to increase due to the larger diameter of the portion that penetrates the metal layer. Consequently, in the metal layer embedded substrate of the present invention, heat generated in the core portion including the metal layer is more easily dissipated to the outside of the first insulating layer and the second insulating layer through the through-conductor.

[0020] In the metal layer embedded substrate of the present invention, the volume of the through-conductor provided in the through-hole is sufficiently secured to dissipate the heat generated in the core. For example, even if the diameter of the through-hole is reduced in an attempt to miniaturize the metal layer embedded substrate of the present invention, the heat generated in the core is sufficiently dissipated to the outside of the first insulating layer and the second insulating layer through the through-conductor.

[0021] Furthermore, when a large current is passed through the core in an attempt to increase the output of the metal layer embedded substrate of the present invention, the core tends to overheat. However, in the metal layer embedded substrate of the present invention, the heat generated in the core is easily dissipated to the outside of the first and second insulating layers through the through-conductor. Therefore, problems such as a decrease in the characteristics of the core (e.g., electrical characteristics) due to residual heat in the core are less likely to occur.

[0022] Therefore, the metal layer embedded substrate of the present invention makes it possible to improve the heat dissipation of the insulating layer (first insulating layer and second insulating layer) to the outside.

[0023] Furthermore, in the metal layer embedded substrate of the present invention, the diameter of the portion of the through-hole that penetrates the metal layer is larger than the diameter of the portion that penetrates the first insulating layer. As a result, the outer shape of the through-conductor provided on at least the inner wall surface of the through-hole bulges outward (protrudes) in a direction intersecting the thickness direction (for example, a direction perpendicular to the thickness direction) as it extends in the thickness direction from the first insulating layer to the metal layer (for example, a stepped shape). Therefore, in the metal layer embedded substrate of the present invention, the contact area between the through-conductor and layers other than the metal layer that exist from the first insulating layer to the metal layer in the thickness direction tends to increase due to the bulging portion of the through-conductor's outer shape as described above. For example, if the metal layer is in contact with the first insulating layer in the thickness direction, the first insulating layer exists as a layer other than the metal layer that exists from the first insulating layer to the metal layer in the thickness direction, and furthermore, the contact area between the first insulating layer and the through-conductor tends to increase due to the bulging portion of the through-conductor's outer shape as described above.

[0024] Similarly, in the metal layer embedded substrate of the present invention, the diameter of the portion of the through-hole that penetrates the metal layer is larger than the diameter of the portion that penetrates the second insulating layer. As a result, the outer shape of the through-conductor bulges outward (protrudes) in a direction that intersects the thickness direction (for example, a direction perpendicular to the thickness direction) as it extends in the thickness direction from the second insulating layer to the metal layer (for example, a stepped shape). Therefore, in the metal layer embedded substrate of the present invention, the contact area between the through-conductor and layers other than the metal layer that exist from the second insulating layer to the metal layer in the thickness direction tends to increase due to the bulging portion of the through-conductor's outer shape as described above. For example, if the metal layer is in contact with the second insulating layer in the thickness direction, the second insulating layer exists as a layer other than the metal layer that exists from the second insulating layer to the metal layer in the thickness direction, and furthermore, the contact area between the second insulating layer and the through-conductor tends to increase due to the bulging portion of the through-conductor's outer shape as described above.

[0025] Thus, in the metal layer embedded substrate of the present invention, as described above, the contact area between the layers other than the metal layer and the through-conductor increases, making it easier for the layers other than the metal layer and the through-conductor to adhere closely together due to the anchoring effect, etc., and as a result, it becomes less likely for the layers other than the metal layer and the through-conductor to peel off.

[0026] Therefore, the metal layer embedded substrate of the present invention makes it possible to improve the peel resistance between layers other than the metal layer and the through-conductor.

[0027] Based on the above, the metal layer embedded substrate of the present invention makes it possible to realize a metal layer embedded substrate that can improve both the heat dissipation of the insulating layer (first insulating layer and second insulating layer) to the outside, and the peeling resistance between layers other than the metal layer and the through conductor.

[0028] The following describes specific examples of the metal layer embedded substrate of the present invention.

[0029] Figure 1 is a schematic cross-sectional view showing an example of a metal layer embedded substrate according to the present invention.

[0030] The metal layer embedded substrate 1 shown in Figure 1 has a core portion 10, a first insulating layer 60A, a second insulating layer 60B, and a through conductor 70.

[0031] <Core section> The core section 10 has a first main surface 10a and a second main surface 10b that are opposite to each other in the thickness direction (vertical direction in Figure 1).

[0032] The number of core portions 10 in the metal layer embedded substrate 1 is not particularly limited. There may be only one core portion 10 or there may be multiple core portions 10 in the metal layer embedded substrate 1. In the latter case, the configuration of each core portion 10 may be the same as each other, different from each other, or partially different.

[0033] The core portion 10 includes a metal layer 20.

[0034] The position of the metal layer 20 in the core portion 10 is not particularly limited. For example, the metal layer 20 may be located in the center of the core portion 10 in the thickness direction, on the side of the first insulating layer 60A relative to the center of the core portion 10, or on the side of the second insulating layer 60B relative to the center of the core portion 10.

[0035] The metal material constituting the metal layer 20 is not particularly limited and may be, for example, a single metal such as aluminum or copper, or an alloy containing at least one of the above-mentioned single metals.

[0036] The number of metal layers 20 in the core portion 10 is not particularly limited. There may be only one metal layer 20 in the core portion 10, or there may be multiple metal layers 20. In the latter case, the metal materials constituting each metal layer 20 may be the same, different from each other, or partially different.

[0037] The core portion 10 only needs to include the metal layer 20. In other words, the core portion 10 may include only the metal layer 20 (in this case, the core portion 10 may be the metal layer 20 itself), or it may include the metal layer 20 plus another layer.

[0038] The positions of the metal layer 20 and the other layer in the core portion 10 are not particularly limited. The core portion 10 may include the other layer between the metal layer 20 and the first insulating layer 60A, or between the metal layer 20 and the second insulating layer 60B, or both of these positions.

[0039] The core part 10 may include, as a layer different from the metal layer 20, for example, a new metal layer, an insulating layer, or the like.

[0040] <First Insulating Layer> The first insulating layer 60A is provided on the first main surface 10a of the core part 10.

[0041] The first insulating layer 60A may be provided over the entire region or only over a partial region on the first main surface 10a of the core part 10.

[0042] The insulating material forming the first insulating layer 60A is not particularly limited, and may be, for example, an insulating resin or the like.

[0043] <Second Insulating Layer> The second insulating layer 60B is provided on the second main surface 10b of the core part 10.

[0044] The second insulating layer 60B may be provided over the entire region or only over a partial region on the second main surface 10b of the core part 10.

[0045] The insulating material forming the second insulating layer 60B is not particularly limited, and may be, for example, an insulating resin or the like.

[0046] The insulating material forming the second insulating layer 60B may be the same as or different from the insulating material forming the first insulating layer 60A.

[0047] <Through Conductor> The through conductor 70 is provided on at least the inner wall surface of a through hole 71 that penetrates the core part 10, the first insulating layer 60A, and the second insulating layer 60B in the thickness direction.

[0048] The through conductor 70 only needs to be provided on at least the inner wall surface of the through hole 71. That is, the through conductor 70 may be provided only on the inner wall surface of the through hole 71 or may be provided over the entire interior of the through hole 71.

[0049] The through conductor 70 is preferably electrically connected to the metal layer 20.

[0050] The conductive material constituting the through-conductor 70 is not particularly limited and may be, for example, a metallic material. In this case, the metallic material constituting the through-conductor 70 is not particularly limited and may be, for example, a single metal such as copper, or an alloy containing at least one of the above-mentioned single metals.

[0051] The number of through conductors 70 is not particularly limited. There may be only one through conductor 70, or there may be multiple through conductors 70. In the latter case, the conductive materials constituting each through conductor 70 may be the same, different from each other, or partially different.

[0052] The planar shape of the through-hole 71 when viewed from the thickness direction is not particularly limited and may be, for example, circular, elliptical, rectangular (square or rectangular), etc.

[0053] The number of through holes 71 is not particularly limited. There may be only one through hole 71, or there may be multiple through holes 71. In the latter case, the planar shape of each through hole 71 when viewed from the thickness direction may be the same as each other, may be different from each other, or may be different in part.

[0054] If the through conductor 70 is provided only on the inner wall surface of the through hole 71, a filling portion 80 filled with a filling material may be provided in the space surrounded by the through conductor 70 within the through hole 71. In this case, since the space within the through hole 71 is eliminated by the filling portion 80, the through conductor 70 becomes less likely to peel off from the through hole 71.

[0055] The filling portion 80 may be a conductor or an insulator. In other words, the filling material constituting the filling portion 80 may be a conductive material or an insulating material.

[0056] The filling material constituting the filling section 80 may be either a conductive material or an insulating material, and its specific type is not particularly limited; for example, it may be a resin material. In other words, the filling material constituting the filling section 80 may be a conductive resin or an insulating resin.

[0057] In the metal layer embedded substrate 1, the diameter P of the through-hole 71 that penetrates the metal layer 20 is larger than the diameter Q of the through-hole 71 that penetrates the first insulating layer 60A and the diameter R of the through-hole 71 that penetrates the second insulating layer 60B.

[0058] In the metal layer embedded substrate 1, the diameter P of the portion of the through-hole 71 that penetrates the metal layer 20 is larger than the diameter Q of the portion that penetrates the first insulating layer 60A and the diameter R of the portion that penetrates the second insulating layer 60B. As a result, the volume of the through-conductor 70 provided in the through-hole 71 tends to increase due to the larger diameter P of the portion that penetrates the metal layer 20. Consequently, in the metal layer embedded substrate 1, the heat generated in the core portion 10 including the metal layer 20 is more easily dissipated to the outside of the first insulating layer 60A and the second insulating layer 60B via the through-conductor 70.

[0059] In the metal layer embedded substrate 1, the volume of the through-conductor 70 provided in the through-hole 71 is sufficient to dissipate the heat generated in the core portion 10. Therefore, even if the diameter of the through-hole 71 is reduced in an attempt to miniaturize the metal layer embedded substrate 1, the heat generated in the core portion 10 is sufficiently dissipated to the outside of the first insulating layer 60A and the second insulating layer 60B via the through-conductor 70.

[0060] Furthermore, when a large current is passed through the core portion 10 in an attempt to increase the output of the metal layer embedded substrate 1, the core portion 10 tends to overheat. However, in the metal layer embedded substrate 1, the heat generated in the core portion 10 is easily dissipated to the outside of the first insulating layer 60A and the second insulating layer 60B through the through-conductor 70. Therefore, problems such as a decrease in the characteristics of the core portion 10 (for example, electrical characteristics) due to residual heat in the core portion 10 are less likely to occur.

[0061] Therefore, the metal layer embedded substrate 1 makes it possible to improve the heat dissipation of the insulating layers (first insulating layer 60A and second insulating layer 60B) to the outside.

[0062] Furthermore, in the metal layer embedded substrate 1, the diameter P of the portion of the through-hole 71 that penetrates the metal layer 20 is larger than the diameter Q of the portion that penetrates the first insulating layer 60A. As a result, as shown in the dashed line in Figure 1, the outer shape of the through-conductor 70 provided on at least the inner wall surface of the through-hole 71 bulges outward (protrudes) in a direction intersecting the thickness direction (for example, a direction perpendicular to the thickness direction) as it extends in the thickness direction from the first insulating layer 60A to the metal layer 20 (for example, a stepped shape). Therefore, in the metal layer embedded substrate 1, the contact area between the layer other than the metal layer 20 (the first insulating layer 60A in Figure 1) and the through-conductor 70 in the thickness direction from the first insulating layer 60A to the metal layer 20 tends to increase due to the bulging portion of the through-conductor 70's outer shape, as described above.

[0063] Similarly, in the metal layer embedded substrate 1, the diameter P of the portion of the through-hole 71 that penetrates the metal layer 20 is larger than the diameter R of the portion that penetrates the second insulating layer 60B. As a result, as shown in the dashed line in Figure 1, the outer shape of the through-conductor 70 bulges outward (protrudes) in a direction that intersects the thickness direction (for example, a direction perpendicular to the thickness direction) as it extends in the thickness direction from the second insulating layer 60B to the metal layer 20 (for example, a stepped shape). Therefore, in the metal layer embedded substrate 1, the contact area between the through-conductor 70 and the layers other than the metal layer 20 that exist in the thickness direction from the second insulating layer 60B to the metal layer 20 (the second insulating layer 60B in Figure 1) tends to increase due to the bulging portion of the outer shape of the through-conductor 70 as described above.

[0064] Thus, in the metal layer embedded substrate 1, the contact area between the layers other than the metal layer 20 (the first insulating layer 60A and the second insulating layer 60B in Figure 1) and the through-conductor 70 increases. As a result, the layers other than the metal layer 20 and the through-conductor 70 adhere more closely together due to the anchoring effect, and consequently, the layers other than the metal layer 20 and the through-conductor 70 become less likely to peel off.

[0065] Therefore, in the metal layer embedded substrate 1, the peel resistance between layers other than the metal layer 20 and the through-conductor 70 can be improved.

[0066] Based on the above, the metal layer embedded substrate 1 makes it possible to realize a metal layer embedded substrate that can improve both the heat dissipation of the insulating layers (first insulating layer 60A and second insulating layer 60B) to the outside, as well as the peeling resistance between layers other than the metal layer 20 and the through-conductor 70.

[0067] In the metal layer embedded substrate 1, from the viewpoint of making the above effects more pronounced, it is preferable that the diameter P of the portion of the through hole 71 that penetrates the metal layer 20 is 1.01 times or more the diameter Q of the portion that penetrates the first insulating layer 60A and the diameter R of the portion that penetrates the second insulating layer 60B.

[0068] In the metal layer embedded substrate 1, from the viewpoint of securing the volume of the metal layer 20, the diameter P of the portion of the through hole 71 that penetrates the metal layer 20 may be 1.5 times or less each of the diameter Q of the portion that penetrates the first insulating layer 60A and the diameter R of the portion that penetrates the second insulating layer 60B.

[0069] The characteristic of the metal layer embedded substrate 1 that "the diameter P of the portion of the through-hole 71 that penetrates the metal layer 20 is larger than the diameter Q of the portion that penetrates the first insulating layer 60A and the diameter R of the portion that penetrates the second insulating layer 60B" can be achieved, for example, by widening the diameter of the portion of the through-hole 71 that penetrates the metal layer 20 during the manufacturing stage of the metal layer embedded substrate 1. For example, during the manufacturing stage of the metal layer embedded substrate 1, after forming the through-hole 71 and before forming the through-conductor 70 (and further filling portion 80), a process can be performed to selectively remove (shave off) the metal layer 20 facing the through-hole 71, thereby widening the diameter of the portion of the through-hole 71 that penetrates the metal layer 20 compared to the diameter of the portion of the through-hole 71 that penetrates other layers (including the first insulating layer 60A and the second insulating layer 60B). The process of selectively removing (shaving off) the metal layer 20 facing the through hole 71 is not particularly limited and may be a chemical process or a physical process.

[0070] Figure 2 is a schematic cross-sectional view showing another example of the through-hole in Figure 1. Figure 3 is a schematic cross-sectional view showing another example of the through-hole in Figure 1, different from that of Figure 2. Figure 4 is a schematic cross-sectional view showing another example of the through-hole in Figure 1, different from that of Figures 2 and 3.

[0071] The diameter P of the portion of the through-hole 71 that penetrates the metal layer 20 may be constant (it may not change) or not constant (it may change) from one side to the other in the thickness direction. In the former case, the outer shape of the portion of the through-hole 71 that penetrates the metal layer 20 when viewed in cross-section along the thickness direction may be straight, for example, as shown in Figures 1 and 4. In the latter case, the outer shape of the portion of the through-hole 71 that penetrates the metal layer 20 when viewed in cross-section along the thickness direction may be curved, for example, as shown in Figures 2 and 3.

[0072] Although the position of the metal layer 20 in the core portion 10 is not shown in Figures 1, 2, 3, and 4, the diameter P of the portion of the through-hole 71 that penetrates the metal layer 20 is determined solely as the diameter of the portion that penetrates the metal layer 20 in the core portion 10. For example, if the core portion 10 includes another layer in addition to the metal layer 20, the diameter P of the portion of the through-hole 71 that penetrates the metal layer 20 is determined as the diameter of the portion that penetrates the metal layer 20 in the core portion 10, not the diameter of the portion that penetrates the other layer in the core portion 10.

[0073] If the core portion 10 includes a metal layer 20 and another layer, the diameter of the portion of the through hole 71 that penetrates the core portion 10, specifically the portion that penetrates the metal layer 20 and the other layer, may be the same as the diameter P of the portion that penetrates the metal layer 20, or it may be different from the diameter P of the portion that penetrates the metal layer 20. In the latter case, the diameter of the portion of the through hole 71 that penetrates the core portion 10, specifically the portion that penetrates the metal layer 20 and the other layer, may be larger than the diameter P of the portion that penetrates the metal layer 20, or it may be smaller than the diameter P of the portion that penetrates the metal layer 20.

[0074] The diameter Q of the portion of the through-hole 71 that penetrates the first insulating layer 60A may be constant (or not change) or not constant (or change) from one side to the other in the thickness direction. In the former case, the outer shape of the portion of the through-hole 71 that penetrates the first insulating layer 60A, when viewed in cross-section along the thickness direction, may be a straight line, for example, as shown in Figure 1. In the latter case, the outer shape of the portion of the through-hole 71 that penetrates the first insulating layer 60A, when viewed in cross-section along the thickness direction, may be a tapered shape, for example, as shown in Figures 2, 3, and 4, where the diameter decreases (or increases) from one side to the other in the thickness direction.

[0075] The diameter R of the portion of the through-hole 71 that penetrates the second insulating layer 60B may be constant (or not change) or not constant (or may change) from one side to the other in the thickness direction. In the former case, the outer shape of the portion of the through-hole 71 that penetrates the second insulating layer 60B when viewed in cross-section along the thickness direction may be a straight line, for example, as shown in Figure 1. In the latter case, the outer shape of the portion of the through-hole 71 that penetrates the second insulating layer 60B when viewed in cross-section along the thickness direction may be a tapered shape, for example, as shown in Figures 2, 3, and 4, where the diameter decreases (or increases) from one side to the other in the thickness direction.

[0076] In the through-hole 71, the diameter Q of the portion that penetrates the first insulating layer 60A and the diameter R of the portion that penetrates the second insulating layer 60B may be the same or different. In the latter case, the diameter Q of the portion that penetrates the first insulating layer 60A may be larger than the diameter R of the portion that penetrates the second insulating layer 60B, or smaller than the diameter R of the portion that penetrates the second insulating layer 60B.

[0077] The diameter of the portion of the through-hole 71 that penetrates the target layer is determined as the equivalent circular diameter calculated from the area of ​​that portion when viewed from the thickness direction. For example, if the planar shape of the through-hole 71 when viewed from the thickness direction is circular in the portion that penetrates the target layer, the diameter of that portion (the diameter in the direction perpendicular to the thickness direction) is determined as the diameter of that portion.

[0078] If the diameter P of the through-hole 71 that penetrates the metal layer 20 is greater than the diameter Q of the portion that penetrates the first insulating layer 60A, then the outer shape of the portion of the through-hole 71 that penetrates the metal layer 20 only needs to bulge (protrude) on at least one side in a direction intersecting the thickness direction (for example, a direction perpendicular to the thickness direction) with respect to the outer shape of the portion that penetrates the first insulating layer 60A. Specifically, it may bulge (protrude) on only one side, or it may bulge (protrude) on both sides.

[0079] If the diameter P of the through-hole 71 that penetrates the metal layer 20 is greater than the diameter R of the portion that penetrates the second insulating layer 60B, then the outer shape of the portion of the through-hole 71 that penetrates the metal layer 20 only needs to bulge (protrude) on at least one side in a direction intersecting the thickness direction (for example, a direction perpendicular to the thickness direction) with respect to the outer shape of the portion that penetrates the second insulating layer 60B. Specifically, it may bulge (protrude) on only one side, or it may bulge (protrude) on both sides.

[0080] In the metal layer embedded substrate 1, in the example shown in Figure 1, only one through-hole 71 is provided. However, if multiple through-holes 71 are provided, the characteristic that "the diameter P of the portion of the through-hole 71 that penetrates the metal layer 20 is larger than the diameter Q of the portion that penetrates the first insulating layer 60A and the diameter R of the portion that penetrates the second insulating layer 60B" only needs to be true for at least one through-hole 71, and may be true for all of the through-holes 71.

[0081] In the metal layer embedded substrate 1, if the core portion 10 includes multiple metal layers 20, the characteristic that "the diameter P of the portion of the through hole 71 that penetrates the metal layer 20 is larger than the diameter Q of the portion that penetrates the first insulating layer 60A and the diameter R of the portion that penetrates the second insulating layer 60B" only needs to be true for at least one metal layer 20, and may be true for all metal layers 20.

[0082] As described above, at least one diameter selected from the group consisting of the diameter P of the portion of the through-hole 71 that penetrates the metal layer 20, the diameter Q of the portion that penetrates the first insulating layer 60A, and the diameter R of the portion that penetrates the second insulating layer 60B may not be constant (may change) from one side to the other in the thickness direction. In this case, the characteristic that "the diameter P of the through-hole 71 that penetrates the metal layer 20 is larger than the diameter Q of the part that penetrates the first insulating layer 60A and the diameter R of the part that penetrates the second insulating layer 60B" is changed to "the maximum value of the diameter P of the through-hole 71 that penetrates the metal layer 20 is larger than the diameter Q of some part of the part that penetrates the first insulating layer 60A and the diameter R of some part of the part that penetrates the second insulating layer 60B," for example, "the maximum value of the diameter P of the through-hole 71 that penetrates the metal layer 20 is larger than the minimum value of the diameter Q of the part that penetrates the first insulating layer 60A and the minimum value of the diameter R of the part that penetrates the second insulating layer 60B."

[0083] The maximum diameter P of the through-hole 71 that penetrates the metal layer 20 may be greater than or less than the maximum diameter Q of the part of the through-hole 60A that penetrates the first insulating layer 60A, for example, the minimum diameter Q of the part of the through-hole 60A that penetrates the first insulating layer 60A. Also, the maximum diameter P of the through-hole 71 that penetrates the metal layer 20 may be greater than or less than the maximum diameter R of the part of the through-hole 60B that penetrates the second insulating layer 60B, for example, the minimum diameter R of the part of the through-hole 60B that penetrates the second insulating layer 60B.

[0084] In the examples shown in Figures 2 and 3, the maximum diameter P of the through-hole 71 that penetrates the metal layer 20 is greater than the minimum diameter Q of the through-hole 71 that penetrates the first insulating layer 60A, and is also greater than the maximum diameter Q of the through-hole 71 that penetrates the first insulating layer 60A. Furthermore, in the examples shown in Figures 2 and 3, the maximum diameter P of the through-hole 71 that penetrates the metal layer 20 is greater than the minimum diameter R of the through-hole 60B, and is also greater than the maximum diameter R of the through-hole 60B.

[0085] In the example shown in Figure 4, the maximum diameter P of the through-hole 71 that penetrates the metal layer 20 is greater than the minimum diameter Q of the through-hole 60A, and less than the maximum diameter Q of the through-hole 60A. Also, in the example shown in Figure 4, the maximum diameter P of the through-hole 71 that penetrates the metal layer 20 is greater than the minimum diameter R of the through-hole 60B, and greater than the maximum diameter R of the through-hole 60B.

[0086] In the metal layer embedded substrate 1, the first insulating layer 60A and the second insulating layer 60B are provided in the thickness direction relative to the core portion 10 (metal layer 20), while the first insulating layer 60A and the second insulating layer 60B may or may not be provided in the direction perpendicular to the thickness direction (left and right direction in Figure 1). In other words, as long as the first insulating layer 60A and the second insulating layer 60B are provided in the thickness direction relative to the core portion 10 (metal layer 20), the core portion 10 (metal layer 20) may or may not be exposed from the first insulating layer 60A and the second insulating layer 60B. Regardless of which of these forms the metal layer embedded substrate 1 is, it is assumed that the metal layer embedded substrate 1 is a metal layer embedded substrate in which the metal layer 20 is embedded in the first insulating layer 60A and the second insulating layer 60B.

[0087] <First Conductor Layer> The metal layer embedded substrate 1 may further have a first conductor layer 90A provided on the surface of the first insulating layer 60A opposite to the core portion 10 and electrically connected to the through conductor 70. In this case, the heat generated in the core portion 10 is more easily dissipated to the outside of the first insulating layer 60A and the second insulating layer 60B through the through conductor 70 and further through the first conductor layer 90A.

[0088] The first conductor layer 90A may be provided over the entire surface of the first insulating layer 60A opposite to the core portion 10, or it may be provided over only a portion of the surface.

[0089] The conductive material constituting the first conductive layer 90A is not particularly limited and may be, for example, a metallic material. In this case, the metallic material constituting the first conductive layer 90A is not particularly limited and may be, for example, a single metal such as copper, or an alloy containing at least one of the above-mentioned single metals.

[0090] <Second Conductor Layer> The metal layer embedded substrate 1 may also have a second conductor layer 90B in addition to the first conductor layer 90A, which is provided on the surface of the second insulating layer 60B opposite to the core portion 10 and electrically connected to the through conductor 70. In this case, the heat generated in the core portion 10 is more easily dissipated to the outside of the first insulating layer 60A and the second insulating layer 60B through the through conductor 70, the first conductor layer 90A, and further to the second conductor layer 90B.

[0091] The second conductor layer 90B may be provided over the entire area of ​​the second insulating layer 60B on the surface opposite to the core portion 10, or it may be provided over only a portion of the area.

[0092] The conductive material constituting the second conductive layer 90B is not particularly limited and may be, for example, a metallic material. In this case, the metallic material constituting the second conductive layer 90B is not particularly limited and may be, for example, a single metal such as copper, or an alloy containing at least one of the above-mentioned single metals.

[0093] The conductive material constituting the second conductor layer 90B may be the same as the conductive material constituting the first conductor layer 90A, or it may be different from the conductive material constituting the first conductor layer 90A.

[0094] The metal layer embedded substrate 1 may further have another conductive layer provided on the surface of the first insulating layer 60A opposite to the core portion 10, and which is not electrically connected to the through conductor 70.

[0095] The metal layer embedded substrate 1 may further have another conductive layer provided on the surface of the second insulating layer 60B opposite to the core portion 10, and which is not electrically connected to the through conductor 70.

[0096] In the following, a capacitor-embedded substrate will be described as an embodiment of the metal layer embedded substrate 1 shown in Figure 1.

[0097] [Capacitor-embedded substrate] Figure 5 is a schematic cross-sectional view showing a capacitor-embedded substrate, which is an embodiment of the metal layer embedded substrate shown in Figure 1.

[0098] The capacitor-embedded substrate 101 shown in Figure 5 includes a capacitor 110, an insulating layer 160, a first through-conductor 170A, and a second through-conductor 170B.

[0099] <Capacitor> The capacitor 110 constitutes the core portion 10 shown in Figure 1. That is, the core portion 10 includes a capacitor 110 having a first electrode layer 120, a dielectric layer 130, and a second electrode layer 140 that faces the first electrode layer 120 in the thickness direction via the dielectric layer 130.

[0100] The following describes an example of a configuration in which the capacitor 110 is an electrolytic capacitor.

[0101] The capacitor 110 has a first main surface 110a and a second main surface 110b that are opposite to each other in the thickness direction.

[0102] The first electrode layer 120 is an anode layer 120A that includes a core portion 121 and a porous portion 122.

[0103] The first electrode layer 120 constitutes the metal layer 20 of the core portion 10 shown in Figure 1. In other words, the anode layer 120A constitutes the metal layer 20 of the core portion 10 shown in Figure 1.

[0104] In the anode layer 120A, the core portion 121 is a portion where pores such as the porous portion 122 are substantially absent. Preferably, the core portion 121 constitutes the central portion in the thickness direction of the anode layer 120A.

[0105] The core portion 121 has a first surface 121a and a second surface 121b, which are a pair of surfaces facing each other in the thickness direction.

[0106] The core portion 121 is preferably made of metal, and more preferably of valve-acting metal. When the core portion 121 is made of valve-acting metal, the anode layer 120A is also called the valve-acting metal substrate.

[0107] The valve-acting metal constituting the core 121 is not particularly limited and may be, for example, a single metal such as aluminum, tantalum, niobium, titanium, or zirconium, or an alloy containing at least one of the above single metals. Among these, the valve-acting metal constituting the core 121 is preferably aluminum or an aluminum alloy.

[0108] The porous portion 122 is provided on at least one of the pair of surfaces of the core portion 121, namely the first surface 121a and the second surface 121b. In other words, the porous portion 122 may be provided only on the first surface 121a of the core portion 121, or only on the second surface 121b of the core portion 121, or on both the first surface 121a and the second surface 121b of the core portion 121. In this way, the anode layer 120A has the porous portion 122 on at least one of the pair of surfaces that are opposite to each other in the thickness direction. As a result, the surface area of ​​the anode layer 120A is increased, making it easier to improve the capacitance of the capacitor 110.

[0109] The porous portion 122 is preferably an etched layer formed by etching the surface of the anode layer 120A (core portion 121).

[0110] The shape of the anode layer 120A is preferably a flat plate (anode plate), and more preferably a foil (anode foil).

[0111] The dielectric layer 130 is provided on the surface of the porous portion 122. Specifically, the dielectric layer 130 is provided along the surface (contour) of the voids present in the porous portion 122.

[0112] The dielectric layer 130 is preferably made of an oxide film of the valve-acting metal described above. For example, if the anode layer 120A is aluminum foil, an oxide film that will become the dielectric layer 130 is formed by performing an anodic oxidation treatment (also called chemical conversion treatment) on the aluminum foil in an aqueous solution containing ammonium adipate or the like. Since the dielectric layer 130 is formed along the surface of the porous portion 122, voids (recesses) will be provided in the dielectric layer 130.

[0113] The second electrode layer 140 is a cathode layer 140A provided on the surface of the dielectric layer 130.

[0114] Preferably, the cathode layer 140A has a solid electrolyte layer 141 provided on the surface of the dielectric layer 130 and a conductive layer 142 provided on the surface of the solid electrolyte layer 141. When the cathode layer 140A has a solid electrolyte layer 141, the capacitor 110 becomes a solid electrolytic capacitor.

[0115] The solid electrolyte layer 141 preferably has an inner layer provided inside the voids of the dielectric layer 130 and an outer layer covering the inner layer.

[0116] The constituent material of the solid electrolyte layer 141 is not particularly limited and may be conductive polymers such as polypyrroles, polythiophenes, and polyanilines. Among these, the constituent material of the solid electrolyte layer 141 is preferably polythiophene, and particularly preferably poly(3,4-ethylenedioxythiophene) (PEDOT). The conductive polymer may also contain a dopant such as polystyrene sulfonic acid (PSS).

[0117] The solid electrolyte layer 141 is formed in a predetermined region on the surface of the dielectric layer 130 by, for example, a method of coating the surface of the dielectric layer 130 with a dispersion of a conductive polymer such as poly(3,4-ethylenedioxythiophene) and drying it, or a method of forming a polymerized film of poly(3,4-ethylenedioxythiophene) or the like on the surface of the dielectric layer 130 using a processing solution containing a polymerizable monomer such as 3,4-ethylenedioxythiophene.

[0118] Preferably, the conductive layer 142 is provided over the entire surface of the solid electrolyte layer 141. However, the conductive layer 142 may be provided over only a portion of the surface of the solid electrolyte layer 141.

[0119] Preferably, the conductive layer 142 includes a conductive resin layer 143 provided on the surface of the solid electrolyte layer 141 and a metal layer 144 provided on the surface of the conductive resin layer 143.

[0120] The conductive layer 142 may contain only one of the conductive resin layer 143 or the metal layer 144. In other words, the conductive layer 142 may contain only the conductive resin layer 143 or only the metal layer 144.

[0121] The conductive resin layer 143 is not particularly limited and may be, for example, a conductive adhesive layer containing at least one conductive filler selected from the group consisting of copper filler, silver filler, nickel filler, and carbon filler.

[0122] The metal layer 144 preferably contains a metal filler.

[0123] The metal filler contained in the metal layer 144 is not particularly limited, but it is preferably at least one selected from the group consisting of copper filler, silver filler, and nickel filler.

[0124] The metal layer 144 may be, for example, a metal plating film, a metal foil, etc. In this case, it is preferable that the metal layer 144 is composed of at least one metal selected from the group consisting of copper, silver, nickel, and an alloy mainly composed of at least one of the above metals.

[0125] In this specification, the main component refers to the component that accounts for the largest weight percentage.

[0126] The conductive layer 142 may include, for example, a carbon layer as a conductive resin layer 143 and a copper layer as a metal layer 144.

[0127] The carbon layer is formed in a predetermined area by, for example, coating a carbon paste containing carbon filler onto the surface of the solid electrolyte layer 141 using a sponge transfer method, screen printing method, dispenser coating method, inkjet printing method, or the like.

[0128] The copper layer is formed in a predetermined area by, for example, applying a copper paste containing copper filler to the surface of the carbon layer using a sponge transfer method, screen printing method, spray coating method, dispenser coating method, inkjet printing method, or the like.

[0129] Of the cathode layer 140A, for example, the metal layer 144 may constitute a new metal layer separate from the metal layer 20 in the core portion 10 described above.

[0130] Preferably, the capacitor 110 further has an insulating mask layer 150 provided on the periphery of the porous portion 122 when viewed in the thickness direction. In this case, the insulating mask layer 150 makes it easier to ensure insulation between the anode layer 120A and the cathode layer 140A, and makes it easier to prevent short circuits between them.

[0131] Preferably, the insulating mask layer 150 is provided over the entire periphery of the porous portion 122 when viewed in the thickness direction. However, the insulating mask layer 150 may be provided only over a portion of the periphery of the porous portion 122 when viewed in the thickness direction.

[0132] The insulating mask layer 150 is preferably provided so as to extend inward from at least one of the pair of surfaces of the anode layer 120A in the thickness direction, and more preferably so as to extend inward from both surfaces of the anode layer 120A.

[0133] The insulating mask layer 150 may or may not be in contact with the core portion 121 in the thickness direction.

[0134] The insulating mask layer 150 may be provided both inside and outside the porous portion 122. In this case, the insulating mask layer 150 may be filled inside the porous portion 122 while also being provided on the surface of the filled porous portion 122. In other words, the thickness of the insulating mask layer 150 may be greater than the thickness of the porous portion 122.

[0135] When the insulating mask layer 150 is provided outside the porous portion 122, it is preferable that the insulating mask layer 150 is provided in a region surrounding the cathode layer 140A when viewed from the thickness direction.

[0136] When viewed from the thickness direction, the insulating mask layer 150 does not have to overlap the cathode layer 140A entirely, nor does it have to overlap the cathode layer 140A partially.

[0137] The insulating material constituting the insulating mask layer 150 is not particularly limited, but it is preferably an insulating resin. In this case, the insulating mask layer 150 makes it easier to ensure sufficient insulation between the anode layer 120A and the cathode layer 140A, and makes it easier to prevent short circuits between them.

[0138] The insulating resin contained in the insulating mask layer 150 is not particularly limited and may be, for example, a composition consisting of polyphenylsulfone (PPS), polyethersulfone (PES), cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, etc.), soluble polyimidesiloxane and epoxy resin, polyimide resin, polyamideimide resin, derivatives or precursors thereof, etc.

[0139] The insulating mask layer 150 is formed on the periphery of the porous portion 122 by, for example, applying the insulating resin described above to both surfaces of the anode layer 120A in a position that overlaps with the periphery of the porous portion 122, and allowing it to penetrate from both surfaces of the anode layer 120A inward.

[0140] The insulating mask layer 150 may constitute a new insulating layer separate from the metal layer 20 in the core portion 10 described above.

[0141] <Insulating Layer> The insulating layer 160 is provided so as to cover both the first main surface 110a and the second main surface 110b of the capacitor 110. This protects the capacitor 110 from the outside with the insulating layer 160. For example, moisture entering the capacitor 110 from the outside is prevented by the insulating layer 160.

[0142] The insulating layer 160 comprises a first insulating layer 60A and a second insulating layer 60B as shown in Figure 1. Specifically, of the insulating layer 160, the first portion 161a covering the first main surface 110a of the capacitor 110 constitutes the first insulating layer 60A, and the second portion 161b covering the second main surface 110b of the capacitor 110 constitutes the second insulating layer 60B.

[0143] When viewed from the thickness direction, it is preferable that the insulating layer 160 overlaps the entire capacitor 110.

[0144] Preferably, the insulating layer 160 is provided so as to conform to the surface shape of the capacitor 110.

[0145] When there are multiple capacitors 110 in the capacitor-embedded substrate 101, it is preferable that an insulating layer 160 is filled in the dividing portion located between adjacent capacitors 110 so as to divide the multiple capacitors 110.

[0146] The insulating material constituting the insulating layer 160 is not particularly limited and may be, for example, an insulating resin.

[0147] The insulating resin contained in the insulating layer 160 is not particularly limited and may be, for example, epoxy resin, phenolic resin, polyimide resin, ABF resin, etc.

[0148] The insulating layer 160 may further contain a filler.

[0149] The filler contained in the insulating layer 160 is not particularly limited and may be an inorganic filler such as silica filler or alumina filler.

[0150] The insulating layer 160 is formed to cover both the first main surface 110a and the second main surface 110b of the capacitor 110 by, for example, performing a process such as heat-pressing an insulating resin sheet onto both the first main surface 110a and the second main surface 110b of the capacitor 110, or applying an insulating resin paste and then heat-curing it.

[0151] <Through-hole conductor> The first through-hole conductor 170A is provided on at least the inner wall surface of the first through-hole 171A that penetrates the capacitor 110 and the insulating layer 160 in the thickness direction.

[0152] The first through conductor 170A is electrically connected to the anode layer 120A.

[0153] Preferably, the first through conductor 170A is electrically connected to the end face of the anode layer 120A facing the inner wall surface of the first through hole 171A in a direction intersecting the thickness direction (for example, a direction perpendicular to the thickness direction).

[0154] Preferably, the core portion 121 and the porous portion 122 are exposed at the end face of the anode layer 120A, which is electrically connected to the first through-conductor 170A. In this case, an electrical connection is made with the first through-conductor 170A not only at the core portion 121 but also at the porous portion 122.

[0155] When viewed from the thickness direction, it is preferable that the first through-conductor 170A is electrically connected to the anode layer 120A around the entire circumference of the first through-hole 171A. In this case, the connection resistance between the first through-conductor 170A and the anode layer 120A tends to decrease, and therefore the equivalent series resistance of the capacitor-embedded substrate 101 tends to decrease.

[0156] The first through-conductor 170A may be electrically connected to the anode layer 120A via an anode protective layer (not shown) provided between the first through-conductor 170A and the anode layer 120A in a direction intersecting the thickness direction (for example, a direction perpendicular to the thickness direction).

[0157] The conductive material constituting the first through-conductor 170A is not particularly limited and may be, for example, a metallic material containing a low-resistance metal such as copper, gold, or silver, or a composite material of the above metal and resin.

[0158] The first through conductor 170A is formed, for example, by plating the inner wall surface of the first through hole 171A with the above-mentioned metal material, or by filling it with the above-mentioned metal material, composite material, etc.

[0159] If the first through conductor 170A is provided only on the inner wall surface of the first through hole 171A, a first filling portion 180A, which is filled with a filling material, may be provided in the space surrounded by the first through conductor 170A within the first through hole 171A. In this case, since the space within the first through hole 171A is eliminated by the first filling portion 180A, the first through conductor 170A becomes less likely to peel off from the first through hole 171A.

[0160] The second through-conductor 170B is provided at a position electrically insulated from the first through-conductor 170A, and is located on at least the inner wall surface of the second through-hole 171B that penetrates the capacitor 110 and the insulating layer 160 in the thickness direction. Since the second through-conductor 170B is electrically insulated from the first through-conductor 170A, it is also electrically insulated from the anode layer 120A which is electrically connected to the first through-conductor 170A.

[0161] The second through conductor 170B is electrically connected to the cathode layer 140A.

[0162] It is preferable that an insulating layer 160 is provided between the capacitor 110 and the second through-conductor 170B in a direction intersecting the thickness direction (for example, a direction perpendicular to the thickness direction). In the example shown in Figure 5, an insulating layer 160 is provided between the anode layer 120A and the second through-conductor 170B in a direction perpendicular to the thickness direction. In this case, insulation between the anode layer 120A and the second through-conductor 170B, and consequently between the anode layer 120A and the cathode layer 140A, is ensured, making it easier to prevent short circuits between them.

[0163] The conductive material constituting the second through-conductor 170B is not particularly limited and may be, for example, a metallic material containing a low-resistance metal such as copper, gold, or silver, or a composite material of the above metal and resin.

[0164] The conductive material constituting the second through-conductor 170B may be the same as the conductive material constituting the first through-conductor 170A, or it may be different from the conductive material constituting the first through-conductor 170A.

[0165] The second through-conductor 170B is formed, for example, by plating the inner wall surface of the second through-hole 171B with the above-mentioned metal material, or by filling it with the above-mentioned metal material, composite material, etc.

[0166] If the second through-conductor 170B is provided only on the inner wall surface of the second through-hole 171B, a second filling portion 180B, which is filled with a filling material, may be provided in the space surrounded by the second through-conductor 170B within the second through-hole 171B. In this case, since the space within the second through-hole 171B is eliminated by the second filling portion 180B, the second through-conductor 170B becomes less likely to peel off from the second through-hole 171B.

[0167] In the capacitor-embedded substrate 101, of the first through-conductor 170A and the second through-conductor 170B, the first through-conductor 170A constitutes the through-conductor 70 shown in Figure 1. In other words, in the capacitor-embedded substrate 101, of the first through-hole 171A and the second through-hole 171B, the first through-hole 171A constitutes the through-hole 71 shown in Figure 1. Specifically, it is as follows.

[0168] In the capacitor-embedded substrate 101, the diameter p of the portion of the first through-hole 171A that penetrates the anode layer 120A is larger than the diameter q of the portion that penetrates the first portion 161a of the insulating layer 160 and the diameter r of the portion that penetrates the second portion 161b of the insulating layer 160.

[0169] In the capacitor-embedded substrate 101, the diameter p of the portion of the first through-hole 171A that penetrates the anode layer 120A is larger than the diameter q of the portion that penetrates the first portion 161a of the insulating layer 160 and the diameter r of the portion that penetrates the second portion 161b of the insulating layer 160. As a result, the volume of the first through-conductor 170A provided in the first through-hole 171A tends to increase due to the larger diameter p of the portion that penetrates the anode layer 120A. Consequently, in the capacitor-embedded substrate 101, the heat generated in the capacitor 110 including the anode layer 120A is more easily dissipated to the outside of the insulating layer 160 through the first through-conductor 170A.

[0170] In the capacitor-integrated substrate 101, the volume of the first through-conductor 170A provided in the first through-hole 171A is sufficient to dissipate the heat generated by the capacitor 110. Therefore, even if the diameter of the first through-hole 171A is reduced in an attempt to miniaturize the capacitor-integrated substrate 101, the heat generated by the capacitor 110 is sufficiently dissipated to the outside of the insulating layer 160 via the first through-conductor 170A.

[0171] Furthermore, if a large current is passed through the capacitor 110 in an attempt to increase the output of the capacitor-integrated substrate 101, the capacitor 110 is prone to overheating. However, in the capacitor-integrated substrate 101, the heat generated in the capacitor 110 is easily dissipated to the outside of the insulating layer 160 through the first through-conductor 170A. Therefore, problems such as a decrease in the characteristics of the capacitor 110 (e.g., electrical characteristics) due to residual heat in the capacitor 110 are less likely to occur.

[0172] Therefore, the capacitor-integrated substrate 101 can improve the heat dissipation of the insulating layer 160 to the outside.

[0173] Furthermore, in the capacitor-embedded substrate 101, the diameter p of the portion of the first through-hole 171A that penetrates the anode layer 120A is larger than the diameter q of the portion that penetrates the first portion 161a of the insulating layer 160. As a result, as shown in the dashed line in Figure 5, the outer shape of the first through-conductor 170A provided on at least the inner wall surface of the first through-hole 171A bulges outward (protrudes) in a direction that intersects the thickness direction (for example, a direction perpendicular to the thickness direction) while extending in the thickness direction from the first portion 161a of the insulating layer 160 to the anode layer 120A (for example, a stepped shape). Therefore, in the capacitor-embedded substrate 101, the contact area between the layers other than the anode layer 120A (the insulating mask layer 150 in Figure 5) that exist in the thickness direction from the first portion 161a of the insulating layer 160 to the anode layer 120A and the first through conductor 170A tends to increase due to the bulging portion of the outer shape of the first through conductor 170A, as described above.

[0174] Similarly, in the capacitor-embedded substrate 101, the diameter p of the portion of the first through-hole 171A that penetrates the anode layer 120A is larger than the diameter r of the portion that penetrates the second portion 161b of the insulating layer 160. As a result, as shown in the dashed line in Figure 5, the outer shape of the first through-conductor 170A bulges outward (protrudes) in a direction that intersects the thickness direction (for example, a direction perpendicular to the thickness direction) as it extends in the thickness direction from the second portion 161b of the insulating layer 160 to the anode layer 120A (for example, a stepped shape). Therefore, in the capacitor-embedded substrate 101, the contact area between the layers other than the anode layer 120A (the insulating mask layer 150 in Figure 5) that exist in the thickness direction from the second portion 161b of the insulating layer 160 to the anode layer 120A tends to increase due to the bulging portion of the outer shape of the first through-conductor 170A as described above.

[0175] Thus, in the capacitor-embedded substrate 101, the increased contact area between the layers other than the anode layer 120A (the insulating mask layer 150 in Figure 5) and the first through-conductor 170A makes it easier for the layers other than the anode layer 120A and the first through-conductor 170A to adhere closely together due to the anchoring effect, etc., and as a result, it becomes less likely for the layers other than the anode layer 120A and the first through-conductor 170A to separate.

[0176] Therefore, in the capacitor-embedded substrate 101, the peeling resistance between layers other than the anode layer 120A and the first through-conductor 170A can be improved.

[0177] Based on the above, the capacitor-embedded substrate 101 makes it possible to realize a capacitor-embedded substrate that can improve both the heat dissipation of the insulating layer 160 to the outside and the peeling resistance between the layers other than the anode layer 120A and the first through-conductor 170A.

[0178] In the capacitor-embedded substrate 101, from the viewpoint of making the above effects more pronounced, it is preferable that the diameter p of the portion of the first through-hole 171A that penetrates the anode layer 120A is 1.01 times or more the diameter q of the portion that penetrates the first portion 161a of the insulating layer 160, and the diameter r of the portion that penetrates the second portion 161b of the insulating layer 160.

[0179] In the capacitor-embedded substrate 101, from the viewpoint of securing the volume of the anode layer 120A, the diameter p of the portion of the first through-hole 171A that penetrates the anode layer 120A may be 1.5 times or less each of the diameter q of the portion that penetrates the first portion 161a of the insulating layer 160 and the diameter r of the portion that penetrates the second portion 161b of the insulating layer 160.

[0180] On the other hand, in the capacitor-embedded substrate 101, the second through-conductor 170B does not constitute the through-conductor 70 shown in Figure 1. In other words, in the capacitor-embedded substrate 101, the second through-hole 171B does not constitute the through-hole 71 shown in Figure 1.

[0181] The cross-sectional shape of the second through-hole 171B when viewed in cross-section along the thickness direction is not particularly limited, and the diameter of the second through-hole 171B may be constant (or not change) from one side to the other in the thickness direction, or it may not be constant (or it may change). In the latter case, the cross-sectional shape of the second through-hole 171B when viewed in cross-section along the thickness direction may be, for example, a tapered shape in which the diameter decreases (or increases) from one side to the other in the thickness direction, or a constricted shape in which the diameter becomes minimal midway from one side to the other in the thickness direction. When the cross-sectional shape of the second through-hole 171B is the constricted shape described above, the outer shape of the constricted shape is not particularly limited, and the position where the diameter becomes minimal is not particularly limited.

[0182] <First Conductor Layer> The capacitor-embedded substrate 101 may further have a first conductor layer 190A provided on the surface opposite to the capacitor 110 in the first portion 161a of the insulating layer 160 and electrically connected to the first through conductor 170A.

[0183] The conductive material constituting the first conductor layer 190A is not particularly limited and may be, for example, a metallic material containing a low-resistance metal such as copper, gold, or silver.

[0184] The conductive material constituting the first conductor layer 190A may be a mixed material of a resin and at least one conductive filler selected from the group consisting of silver filler, copper filler, nickel filler, and carbon filler. In this case, the first conductor layer 190A and the first through conductor 170A will adhere more easily.

[0185] The first conductor layer 190A is formed, for example, by plating with the above-mentioned metal material from the surface of the first portion 161a of the insulating layer 160 opposite to the capacitor 110 to the end of the first through conductor 170A.

[0186] <Second Conductor Layer> The capacitor-embedded substrate 101 may further have a second conductor layer 190B in addition to the first conductor layer 190A, which is provided on the surface of the second portion 161b of the insulating layer 160 opposite to the capacitor 110 and electrically connected to the first through conductor 170A.

[0187] The conductive material constituting the second conductor layer 190B is not particularly limited and may be, for example, a metallic material containing a low-resistance metal such as copper, gold, or silver.

[0188] The conductive material constituting the second conductor layer 190B may be a mixed material of a resin and at least one conductive filler selected from the group consisting of silver filler, copper filler, nickel filler, and carbon filler. In this case, the second conductor layer 190B and the first through conductor 170A will adhere more easily.

[0189] The conductive material constituting the second conductor layer 190B may be the same as the conductive material constituting the first conductor layer 190A, or it may be different from the conductive material constituting the first conductor layer 190A.

[0190] The second conductor layer 190B is formed, for example, by plating with the aforementioned metal material from the surface of the second portion 161b of the insulating layer 160 opposite to the capacitor 110 to the end of the first through conductor 170A.

[0191] The capacitor-embedded substrate 101 may further have another conductor layer 191A provided on the surface of the first portion 161a of the insulating layer 160 opposite to the capacitor 110, and not electrically connected to the first through-conductor 170A. In the example shown in Figure 5, the conductor layer 191A is provided on the surface of the first portion 161a of the insulating layer 160 opposite to the capacitor 110, in a position electrically insulated from the first conductor layer 190A, and is electrically connected to the second through-conductor 170B.

[0192] The conductive material constituting the conductive layer 191A may be the same as the conductive material constituting the first conductive layer 190A or the second conductive layer 190B, or it may be different from the conductive material constituting the first conductive layer 190A or the second conductive layer 190B.

[0193] The capacitor-embedded substrate 101 may further have another conductor layer 191B provided on the surface of the second portion 161b of the insulating layer 160 opposite to the capacitor 110, and not electrically connected to the first through-conductor 170A. In the example shown in Figure 5, the conductor layer 191B is provided on the surface of the second portion 161b of the insulating layer 160 opposite to the capacitor 110, in a position electrically insulated from the second conductor layer 190B, and is electrically connected to the second through-conductor 170B.

[0194] The conductive material constituting the conductive layer 191B may be the same as the conductive material constituting the first conductive layer 190A or the second conductive layer 190B, or it may be different from the conductive material constituting the first conductive layer 190A or the second conductive layer 190B.

[0195] The conductive material constituting the conductive layer 191B may be the same as the conductive material constituting the conductive layer 191A, or it may be different from the conductive material constituting the conductive layer 191A.

[0196] <Via Conductor> The capacitor-embedded substrate 101 may further have via conductors 195A provided on at least the inner wall surface of through holes 196A that penetrate the insulating layer 160 in the thickness direction, so as to electrically connect the cathode layer 140A and the conductor layer 191A.

[0197] The conductive material constituting the via conductor 195A is not particularly limited and may be, for example, a metallic material containing a low-resistance metal such as copper, gold, or silver.

[0198] The via conductor 195A is formed, for example, by plating the inner wall surface with the aforementioned metal material or by filling it with conductive paste and then performing heat treatment on a through hole 196A that penetrates the first portion 161a of the insulating layer 160 in the thickness direction so as to reach the cathode layer 140A constituting the first main surface 110a of the capacitor 110.

[0199] The capacitor-embedded substrate 101 may also have via conductors 195B in addition to the via conductors 195A, which are provided on at least the inner wall surface of through holes 196B that penetrate the insulating layer 160 in the thickness direction, in order to electrically connect the cathode layer 140A and the conductor layer 191B.

[0200] The conductive material constituting the via conductor 195B is not particularly limited and may be, for example, a metallic material containing a low-resistance metal such as copper, gold, or silver.

[0201] The conductive material constituting the via conductor 195B may be the same as the conductive material constituting the via conductor 195A, or it may be different from the conductive material constituting the via conductor 195A.

[0202] The via conductor 195B is formed, for example, by plating the inner wall surface with the aforementioned metal material or by filling it with conductive paste and then performing heat treatment on a through hole 196B that penetrates the second portion 161b of the insulating layer 160 in the thickness direction so as to reach the cathode layer 140A constituting the second main surface 110b of the capacitor 110.

[0203] The capacitor-integrated circuit board 101 is manufactured, for example, as follows.

[0204] <Process for preparing the anode layer> Figure 6 is a schematic cross-sectional view showing an example of the process for preparing the anode layer in the manufacturing method of the capacitor-embedded substrate shown in Figure 5.

[0205] In the process shown in Figure 6, the anode layer 120A is prepared.

[0206] In the example shown in Figure 6, the anode layer 120A includes a core portion 121 and porous portions 122 provided on both the first surface 121a and the second surface 121b of the core portion 121.

[0207] The porous portion 122 is formed, for example, by etching both surfaces of the core portion 121.

[0208] <Process for forming the dielectric layer> Figure 7 is a schematic cross-sectional view showing an example of the process for forming the dielectric layer in the manufacturing method of the capacitor-embedded substrate shown in Figure 5.

[0209] In the process shown in Figure 7, the dielectric layer 130 is formed on the surface of the porous portion 122. For example, by performing an anodic oxidation treatment on the anode layer 120A, in which porous portions 122 are provided on both surfaces of the core portion 121, an oxide film that will become the dielectric layer 130 is formed on the surface of the porous portion 122.

[0210] Alternatively, the steps shown in Figures 6 and 7 may be combined by preparing a chemical foil as the component having the anode layer 120A and the dielectric layer 130.

[0211] <Process for forming an insulating mask layer> Figure 8 is a schematic cross-sectional view showing an example of the process for forming an insulating mask layer in the manufacturing method of the capacitor-embedded substrate shown in Figure 5.

[0212] In the process shown in Figure 8, an insulating mask layer 150 is formed on the surface of the porous portion 122. For example, an insulating resin is applied to the surface of the anode layer 120A at a position overlapping the porous portion 122, and the insulating mask layer 150 is formed on the surface of the porous portion 122 by allowing the resin to penetrate from both surfaces of the anode layer 120A inward.

[0213] The insulating mask layer 150 may be formed on the porous portion 122 at a timing before the dielectric layer 130 is formed, or at a timing after the dielectric layer 130 is formed.

[0214] <Process for forming the solid electrolyte layer> Figure 9 is a schematic cross-sectional view showing an example of the process for forming the solid electrolyte layer in the manufacturing method of the capacitor-embedded substrate shown in Figure 5.

[0215] In the process shown in Figure 9, the solid electrolyte layer 141 is formed on the surface of the dielectric layer 130. For example, the solid electrolyte layer 141 is formed in a predetermined area on the surface of the dielectric layer 130 by methods such as coating a dispersion of a conductive polymer such as poly(3,4-ethylenedioxythiophene) onto the surface of the dielectric layer 130 and drying it, or by using a processing solution containing a polymerizable monomer such as 3,4-ethylenedioxythiophene to form a polymerized film of poly(3,4-ethylenedioxythiophene) on the surface of the dielectric layer 130. At this time, since the insulating mask layer 150 is formed in advance as described above, the insulating mask layer 150 makes it easier to insulate the solid electrolyte layer 141 from the anode layer 120A.

[0216] <Process for forming the conductive layer> Figure 10 is a schematic cross-sectional view showing an example of the process for forming the conductive layer in the manufacturing method of the capacitor-embedded substrate shown in Figure 5.

[0217] In the process shown in Figure 10, a conductive layer 142 is formed on the surface of the solid electrolyte layer 141.

[0218] In the example shown in Figure 10, the conductive layer 142 includes a conductive resin layer 143 provided on the surface of the solid electrolyte layer 141 and a metal layer 144 provided on the surface of the conductive resin layer 143.

[0219] The conductive resin layer 143 is formed in a predetermined area on the surface of the solid electrolyte layer 141 by, for example, applying a conductive paste containing a conductive filler to the surface of the solid electrolyte layer 141 using a sponge transfer method, screen printing method, dispenser coating method, inkjet printing method, etc.

[0220] The metal body layer 144 is formed in a predetermined area on the surface of the conductive resin layer 143 by, for example, applying a metal paste containing a metal filler to the surface of the conductive resin layer 143 using a sponge transfer method, screen printing method, spray coating method, dispenser coating method, inkjet printing method, etc.

[0221] A cathode layer 140A having a solid electrolyte layer 141 and a conductive layer 142 is formed by the steps shown in Figures 9 and 10.

[0222] A capacitor 110 having an anode layer 120A, a dielectric layer 130, and a cathode layer 140A is manufactured by the process shown in Figures 6, 7, 8, 9, and 10.

[0223] <Process of forming through holes in the capacitor> Figure 11 is a schematic cross-sectional view showing an example of the process of forming through holes in the capacitor, in the manufacturing method of the capacitor-embedded substrate shown in Figure 5.

[0224] In the process shown in Figure 11, a through-hole 271 is formed that penetrates the capacitor 110 in the thickness direction. For example, by performing laser processing, drilling, etc., a through-hole 271 is formed that penetrates the anode layer 120A in the thickness direction but does not penetrate the cathode layer 140A in the thickness direction.

[0225] <Process for forming the insulating layer> Figure 12 is a schematic cross-sectional view showing an example of the process for forming the insulating layer in the manufacturing method of the capacitor-embedded substrate shown in Figure 5.

[0226] In the process shown in Figure 12, the insulating layer 160 is formed to cover both the first main surface 110a and the second main surface 110b of the capacitor 110. For example, the insulating layer 160 is formed to cover both the first main surface 110a and the second main surface 110b of the capacitor 110 by performing processes such as heat-pressing an insulating resin sheet onto the main surface, or applying an insulating resin paste and then heat-curing it. At this time, the insulating layer 160 is formed to fill the through-holes 271.

[0227] In the example shown in Figure 12, the insulating layer 160 includes a first portion 161a that covers the first main surface 110a of the capacitor 110, and a second portion 161b that covers the second main surface 110b of the capacitor 110.

[0228] <Step of forming through holes in the capacitor and insulating layer> Figure 13 is a schematic cross-sectional view showing an example of the step of forming through holes in the capacitor and insulating layer in the manufacturing method of the capacitor-embedded substrate shown in Figure 5.

[0229] In the process shown in Figure 13, through-holes 171A' are formed that penetrate the capacitor 110 and the insulating layer 160 in the thickness direction. Specifically, in the region where the insulating layer 160 and the anode layer 120A overlap, but the cathode layer 140A does not overlap, through-holes 171A' are formed that penetrate the insulating layer 160 and the anode layer 120A in the thickness direction, but not the cathode layer 140A, by, for example, laser processing, drilling, etc.

[0230] Furthermore, in the process shown in Figure 13, a second through-hole 171B that penetrates the insulating layer 160 in the thickness direction may be formed in the portion of the insulating layer 160 that is filled in the through-hole 271 by, for example, laser processing, drilling, etc.

[0231] Furthermore, in the process shown in Figure 13, a through-hole 196A may be formed in the first portion 161a of the insulating layer 160 that covers the cathode layer 140A constituting the first main surface 110a of the capacitor 110, by, for example, laser processing, drilling, etc., so as to reach the cathode layer 140A (metal body layer 144 of the conductive layer 142 in Figure 13) and penetrate the first portion 161a of the insulating layer 160 in the thickness direction.

[0232] Furthermore, in the process shown in Figure 13, a through-hole 196B may be formed in the thickness direction of the second portion 161b of the insulating layer 160, by, for example, laser processing, drilling, etc., in the portion of the second portion 161b of the insulating layer 160 that covers the cathode layer 140A which constitutes the second main surface 110b of the capacitor 110, so as to reach the cathode layer 140A (metal body layer 144 of the conductive layer 142 in Figure 13).

[0233] <Process of partially widening the diameter of the through-hole> Figure 14 is a schematic cross-sectional view showing an example of a process of partially widening the diameter of the through-hole in the manufacturing method of the capacitor-embedded substrate shown in Figure 5.

[0234] In the process shown in Figure 14, the first through-hole 171A is formed by partially widening the diameter of the through-hole 171A'. Specifically, the first through-hole 171A is formed by widening the diameter of the portion of the through-hole 171A' that penetrates the anode layer 120A. For example, if wet desmearing is performed on the through-hole 171A', which also serves to remove the residue generated when forming the through-hole 171A' in the process shown in Figure 13, the anode layer 120A facing the inner wall surface of the through-hole 171A' becomes more easily soluble in the chemical solution used for wet desmearing than other layers facing the inner wall surface of the through-hole 171A' (for example, the insulating mask layer 150 and the insulating layer 160). Thus, when wet desmearing is performed on the through-hole 171A', the anode layer 120A facing the inner wall surface of the through-hole 171A' is selectively removed, and as a result, the diameter of the portion of the through-hole 171A' that penetrates the anode layer 120A tends to be wider than the diameter of the portion of the through-hole 171A' that penetrates other layers (for example, the insulating mask layer 150, the insulating layer 160).

[0235] Furthermore, if a dry desmear treatment (e.g., oxygen plasma treatment) is performed on the through-hole 171A' instead of a wet desmear treatment, the anode layer 120A facing the inner wall surface of the through-hole 171A' will not be selectively removed. Therefore, it is difficult to obtain a condition in which the diameter of the portion of the through-hole 171A' that penetrates the anode layer 120A is larger than the diameter of the portion of the through-hole 171A' that penetrates other layers (e.g., the insulating mask layer 150, the insulating layer 160).

[0236] The method for widening the diameter of the portion of the through-hole 171A' that penetrates the anode layer 120A is not limited to the wet desmearing treatment described above. For example, the diameter of the portion of the through-hole 171A' that penetrates the anode layer 120A may be widened by removing the anode layer 120A facing the inner wall surface of the through-hole 171A' through chemical treatment such as etching, or by removing it through physical treatment such as polishing.

[0237] <Process for forming through-conductors> Figure 15 is a schematic cross-sectional view showing an example of the process for forming through-conductors in the manufacturing method of the capacitor-embedded substrate shown in Figure 5.

[0238] In the process shown in Figure 15, the first through-conductor 170A is formed on at least the inner wall surface of the first through-hole 171A. In the example shown in Figure 15, the first through-conductor 170A is formed only on the inner wall surface of the first through-hole 171A. For example, the first through-conductor 170A is formed by plating the inner wall surface of the first through-hole 171A with a metallic material.

[0239] Furthermore, in the process shown in Figure 15, the second through-conductor 170B may be formed on at least the inner wall surface of the second through-hole 171B. For example, the second through-conductor 170B may be formed only on the inner wall surface of the second through-hole 171B by plating the inner wall surface of the second through-hole 171B with a metallic material.

[0240] Furthermore, in the process shown in Figure 15, via conductors 195A may be formed on at least the inner wall surface of the through hole 196A. For example, via conductors 195A may be formed throughout the entire interior of the through hole 196A by filling the through hole 196A with conductive paste and then performing a heat treatment.

[0241] Furthermore, in the process shown in Figure 15, via conductors 195B may be formed on at least the inner wall surface of the through hole 196B. For example, via conductors 195B may be formed throughout the entire interior of the through hole 196B by filling the through hole 196B with conductive paste and then performing a heat treatment.

[0242] <Process for forming the filled area> Figure 16 is a schematic cross-sectional view showing an example of the process for forming the filled area in the manufacturing method of the capacitor-embedded substrate shown in Figure 5.

[0243] In the process shown in Figure 16, a first filling portion 180A is formed in the space surrounded by the first through-conductor 170A within the first through-hole 171A. For example, the first filling portion 180A is formed by filling the space surrounded by the first through-conductor 170A within the first through-hole 171A with a filling material such as a conductive material or an insulating material.

[0244] Furthermore, in the process shown in Figure 16, a second filling portion 180B may be formed in the space surrounded by the second through-conductor 170B within the second through-hole 171B. For example, the second filling portion 180B may be formed by filling the space surrounded by the second through-conductor 170B within the second through-hole 171B with a filling material such as a conductive material or an insulating material.

[0245] <Process for forming the conductor layer> Figure 17 is a schematic cross-sectional view showing an example of the process for forming the conductor layer in the manufacturing method of the capacitor-embedded substrate shown in Figure 5.

[0246] In the process shown in Figure 17, a first conductor layer 190A is formed on the surface of the first portion 161a of the insulating layer 160 opposite to the capacitor 110 and electrically connected to the first through conductor 170A. For example, the first conductor layer 190A is formed by plating with a metallic material from the surface of the first portion 161a of the insulating layer 160 opposite to the capacitor 110 to the end of the first through conductor 170A. In this case, after plating with a metallic material on the surface of the first portion 161a of the insulating layer 160 opposite to the capacitor 110, patterning may be performed to achieve a predetermined shape.

[0247] Furthermore, in the process shown in Figure 17, a second conductor layer 190B is formed on the surface of the second portion 161b of the insulating layer 160 opposite to the capacitor 110 and electrically connected to the first through conductor 170A. For example, the second conductor layer 190B is formed by plating with a metallic material from the surface of the second portion 161b of the insulating layer 160 opposite to the capacitor 110 to the end of the first through conductor 170A. In this case, after plating with a metallic material on the surface of the second portion 161b of the insulating layer 160 opposite to the capacitor 110, patterning may be performed to achieve a predetermined shape.

[0248] Furthermore, in the process shown in Figure 17, a conductor layer 191A may be formed on the surface of the first portion 161a of the insulating layer 160 opposite to the capacitor 110, in a position electrically insulated from the first conductor layer 190A, and electrically connected to the second through conductor 170B. For example, the conductor layer 191A may be formed by plating with a metallic material from the surface of the first portion 161a of the insulating layer 160 opposite to the capacitor 110 to the end of the second through conductor 170B. In this case, after plating with a metallic material on the surface of the first portion 161a of the insulating layer 160 opposite to the capacitor 110, patterning may be performed to achieve a predetermined shape.

[0249] Furthermore, in the process shown in Figure 17, a conductor layer 191B may be formed on the surface of the second portion 161b of the insulating layer 160 opposite to the capacitor 110, in a position electrically insulated from the second conductor layer 190B, and electrically connected to the second through conductor 170B. For example, the conductor layer 191B may be formed by plating with a metallic material from the surface of the second portion 161b of the insulating layer 160 opposite to the capacitor 110 to the end of the second through conductor 170B. In this case, after plating with a metallic material on the surface of the second portion 161b of the insulating layer 160 opposite to the capacitor 110, patterning may be performed to achieve a predetermined shape.

[0250] Through the above process, the capacitor-embedded circuit board 101 is manufactured.

[0251] In the capacitor-embedded substrate 101 manufactured by the above process, the diameter p of the portion of the first through-hole 171A that penetrates the anode layer 120A is larger than the diameter q of the portion that penetrates the first portion 161a of the insulating layer 160 and the diameter r of the portion that penetrates the second portion 161b of the insulating layer 160.

[0252] [Modified Examples of Metal Layer Embedded Substrate] Figure 18 is a schematic cross-sectional view showing modified examples of the metal layer embedded substrate of the present invention.

[0253] In the metal layer embedded substrate 1' shown in Figure 18, the core portion 10 further includes a base layer 25 in addition to the metal layer 20.

[0254] The base layer 25 has a first surface 25a and a second surface 25b, which are a pair of surfaces facing each other in the thickness direction.

[0255] The constituent materials of the base layer 25 are not particularly limited and may include, for example, organic materials such as resins, inorganic materials such as glass, etc.

[0256] The metal layer 20 is provided on at least one of the two surfaces of the base layer 25, namely the first surface 25a and the second surface 25b. In the example shown in Figure 18, the metal layer 20 is provided on both the first surface 25a and the second surface 25b of the base layer 25. Specifically, the metal layer 20 includes a metal layer 20a provided on the first surface 25a of the base layer 25 and a metal layer 20b provided on the second surface 25b of the base layer 25.

[0257] The metal layer 20 may be provided on only one of the first surface 25a and the second surface 25b of the base layer 25.

[0258] In the metal layer embedded substrate 1', the through-holes 71 that penetrate the core portion 10, the first insulating layer 60A, and the second insulating layer 60B in the thickness direction include through-holes 71a and 71b.

[0259] In the metal layer embedded substrate 1', the through conductor 70 provided on at least the inner wall surface of the through hole 71 includes a through conductor 70a provided on at least the inner wall surface of the through hole 71a and a through conductor 70b provided on at least the inner wall surface of the through hole 71b.

[0260] In the metal layer embedded substrate 1', at least one of the diameters P1a of the through-hole 71a that penetrates the metal layer 20a and P2a of the through-hole 71a that penetrates the metal layer 20b is larger than the diameter Qa of the through-hole 71a that penetrates the first insulating layer 60A and the diameter Ra of the through-hole 71a that penetrates the second insulating layer 60B. In the example shown in Figure 18, both the diameter P1a of the through-hole 71a that penetrates the metal layer 20a and the diameter P2a of the through-hole 71a that penetrates the metal layer 20b are larger than the diameter Qa of the through-hole 71a and the diameter Ra of the through-hole 71a that penetrates the first insulating layer 60A and the diameter Ra of the through-hole 71a that penetrates the second insulating layer 60B.

[0261] In addition, it is possible that only one of the diameters P1a of the through-hole 71a that penetrates the metal layer 20a and P2a of the through-hole 20b is larger than the diameter Qa of the through-hole 60A and the diameter Ra of the through-hole 60B.

[0262] In the metal layer embedded substrate 1', at least one of the diameters P1a of the through-hole 71a that penetrates the metal layer 20a and P2a of the through-hole 71a that penetrates the metal layer 20b may be different from the diameter Sa of the portion that penetrates the base layer 25. For example, in the metal layer embedded substrate 1', at least one of the diameters P1a of the through-hole 71a that penetrates the metal layer 20a and P2a of the through-hole 71a that penetrates the metal layer 20b may be larger than the diameter Sa of the portion that penetrates the base layer 25. In the example shown in Figure 18, both the diameter P1a of the through-hole 71a that penetrates the metal layer 20a and the diameter P2a of the through-hole 71a that penetrates the metal layer 20b are larger than the diameter Sa of the portion that penetrates the base layer 25.

[0263] In addition, it is possible that only one of the two diameters of the through-hole 71a—P1a of the portion that penetrates the metal layer 20a and P2a of the portion that penetrates the metal layer 20b—is larger than the diameter Sa of the portion that penetrates the base layer 25.

[0264] In the metal layer embedded substrate 1', if at least one of the diameters P1a of the portion of the through-hole 71a that penetrates the metal layer 20a and P2a of the portion that penetrates the metal layer 20b is larger than the diameter Sa of the portion that penetrates the base layer 25, then, as shown in Figure 18, the outer shape of the through-conductor 70a provided on at least the inner wall surface of the through-hole 71a will bulge outward (protrude) in a direction intersecting the thickness direction (for example, a direction perpendicular to the thickness direction) at least one of the portions extending in the thickness direction from the base layer 25 to the metal layer 20a and the portion extending in the thickness direction from the base layer 25 to the metal layer 20b (for example, a stepped shape). Therefore, in the metal layer embedded substrate 1', the contact area between the base layer 25 and the through-conductor 70a tends to increase due to the bulging portion of the through-conductor 70a's outer shape as described above. Thus, in the metal layer embedded substrate 1', the increased contact area between the base layer 25 and the through-conductor 70a makes it easier for the base layer 25 and the through-conductor 70a to adhere closely together due to the anchoring effect, and as a result, the base layer 25 and the through-conductor 70a become less likely to peel off.

[0265] In the through-hole 71a, the diameter Qa of the portion that penetrates the first insulating layer 60A and the diameter Sa of the portion that penetrates the base layer 25 may be the same or different. In the latter case, the diameter Qa of the portion that penetrates the first insulating layer 60A may be larger than or smaller than the diameter Sa of the portion that penetrates the base layer 25.

[0266] In the through-hole 71a, the diameter Ra of the portion that penetrates the second insulating layer 60B and the diameter Sa of the portion that penetrates the base layer 25 may be the same or different. In the latter case, the diameter Ra of the portion that penetrates the second insulating layer 60B in the through-hole 71a may be larger than the diameter Sa of the portion that penetrates the base layer 25, or it may be smaller than the diameter Sa of the portion that penetrates the base layer 25.

[0267] In the metal layer embedded substrate 1', at least one of the diameters P1b of the through-hole 71b that penetrates the metal layer 20a and P2b of the through-hole 71b that penetrates the metal layer 20b is larger than the diameter Qb of the through-hole 71b that penetrates the first insulating layer 60A and the diameter Rb of the through-hole 71b that penetrates the second insulating layer 60B. In the example shown in Figure 18, both the diameter P1b of the through-hole 71b that penetrates the metal layer 20a and the diameter P2b of the through-hole 71b that penetrates the metal layer 20b are larger than the diameter Qb of the through-hole 71b that penetrates the first insulating layer 60A and the diameter Rb of the through-hole 71b that penetrates the second insulating layer 60B.

[0268] In addition, it is possible that only one of the diameters P1b of the through-hole 71b that penetrates the metal layer 20a and P2b of the through-hole 71b that penetrates the metal layer 20b is larger than the diameter Qb of the through-hole 60A and the diameter Rb of the through-hole 60B.

[0269] In the metal layer embedded substrate 1', at least one of the diameters P1b of the through-hole 71b that penetrates the metal layer 20a and P2b of the through-hole 71b that penetrates the metal layer 20b may be different from the diameter Sb of the portion that penetrates the base layer 25. For example, in the metal layer embedded substrate 1', at least one of the diameters P1b of the through-hole 71b that penetrates the metal layer 20a and P2b of the through-hole 71b may be smaller than the diameter Sb of the portion that penetrates the base layer 25. In the example shown in Figure 18, both the diameter P1b of the through-hole 71b that penetrates the metal layer 20a and the diameter P2b of the through-hole 71b that penetrates the metal layer 20b are smaller than the diameter Sb of the portion that penetrates the base layer 25.

[0270] In addition, it is possible that only one of the diameters P1b of the through-hole 71b that penetrates the metal layer 20a and P2b of the through-hole that penetrates the metal layer 20b is smaller than the diameter Sb of the portion that penetrates the base layer 25.

[0271] In the metal layer embedded substrate 1', if at least one of the diameters P1b of the portion of the through-hole 71b that penetrates the metal layer 20a and P2b of the portion that penetrates the metal layer 20b is smaller than the diameter Sb of the portion that penetrates the base layer 25, then, as shown in Figure 18, the outer shape of the through-conductor 70b provided on at least the inner wall surface of the through-hole 71b will bulge outward (protrude) in a direction intersecting the thickness direction (for example, a direction perpendicular to the thickness direction) at least one of the points where it extends in the thickness direction from the metal layer 20a to the base layer 25 and where it extends in the thickness direction from the metal layer 20b to the base layer 25 (for example, a stepped shape). Therefore, in the metal layer embedded substrate 1', the contact area between at least one of the metal layer 20a and the metal layer 20b and the through-conductor 70b tends to increase due to the bulging portion of the through-conductor 70b's outer shape as described above. Thus, in the metal layer embedded substrate 1', the contact area between at least one of the metal layers 20a and 20b and the through-conductor 70b increases, and due to the anchoring effect and the like, at least one of the metal layers 20a and 20b and the through-conductor 70b become more closely bonded, and as a result, at least one of the metal layers 20a and 20b and the through-conductor 70b become less likely to peel off.

[0272] The metal layer embedded substrate 1' shown in Figure 18 is the same as the metal layer embedded substrate 1 shown in Figure 1, except for the configuration described above.

[0273] Unlike the metal layer embedded substrate 1' shown in Figure 18, at least one of the diameters P1a of the through-hole 71a that penetrates the metal layer 20a and P2a of the through-hole that penetrates the metal layer 20b may be the same as the diameter Sa of the portion that penetrates the base layer 25.

[0274] Furthermore, unlike the metal layer embedded substrate 1' shown in Figure 18, at least one of the diameters P1b of the through-hole 71b that penetrates the metal layer 20a and P2b of the through-hole 71b that penetrates the metal layer 20b may be the same as the diameter Sb of the portion that penetrates the base layer 25.

[0275] In the following, a capacitor-embedded substrate will be described as an embodiment of the metal layer embedded substrate 1' shown in Figure 18.

[0276] [Modified Example of Capacitor-Integrated Substrate] Figure 19 is a schematic cross-sectional view showing a capacitor-integrated substrate, which is an embodiment of the metal layer embedded substrate shown in Figure 18.

[0277] The capacitor-embedded substrate 101' shown in Figure 19 further includes a base layer 125 in addition to the capacitor 110, insulating layer 160, first through-conductor 170A, and second through-conductor 170B.

[0278] The base layer 125 constitutes the base layer 25 of the core portion 10 shown in Figure 18.

[0279] The base layer 125 has a first surface 125a and a second surface 125b, which are a pair of surfaces facing each other in the thickness direction.

[0280] The anode layer 120A is provided on at least one of the pair of surfaces of the base layer 125, namely the first surface 125a and the second surface 125b. In the example shown in Figure 19, the anode layer 120A is provided on both the first surface 125a and the second surface 125b of the base layer 125. The anode layer 120A provided on the first surface 125a of the base layer 125 constitutes the metal layer 20a shown in Figure 18, and the anode layer 120A provided on the second surface 125b of the base layer 125 constitutes the metal layer 20b shown in Figure 18.

[0281] The anode layer 120A may be provided on only one of the first surface 125a and the second surface 125b of the base layer 125.

[0282] The anode layer 120A includes a core portion 121 and a porous portion 122 in order from the base layer 125 side toward the opposite side of the base layer 125 (insulating layer 160 side). Alternatively, the anode layer 120A may also include a core portion 121 and a porous portion 122 in order from the opposite side of the base layer 125 (insulating layer 160 side) toward the base layer 125 side.

[0283] The first through conductor 170A constitutes the through conductor 70a shown in Figure 18. The first through hole 171A constitutes the through hole 71a shown in Figure 18.

[0284] In the capacitor-embedded substrate 101', at least one of the diameters of the first through-hole 171A, specifically the diameter p1a of the portion that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and the diameter p2a of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125, is larger than the diameter qa of the portion that penetrates the first portion 161a of the insulating layer 160 and the diameter ra of the portion that penetrates the second portion 161b of the insulating layer 160. In the example shown in Figure 19, both the diameter p1a of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125, and the diameter p2a of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125, are larger than the diameter qa of the portion that penetrates the first portion 161a of the insulating layer 160, and the diameter ra of the portion that penetrates the second portion 161b of the insulating layer 160.

[0285] Furthermore, of the first through-hole 171A, only one of the diameters p1a of the portion that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and p2a of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125 may be larger than the diameter qa of the portion that penetrates the first portion 161a of the insulating layer 160 and the diameter ra of the portion that penetrates the second portion 161b of the insulating layer 160.

[0286] In the capacitor-embedded substrate 101', at least one of the diameters p1a of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and p2a of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125 may be different from the diameter sa of the portion that penetrates the base layer 125. For example, in the capacitor-embedded substrate 101', at least one of the diameters p1a of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and p2a of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125 may be larger than the diameter sa of the portion that penetrates the base layer 125. In the example shown in Figure 19, both the diameter p1a of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125, and the diameter p2a of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125, are larger than the diameter sa of the portion that penetrates the base layer 125.

[0287] Furthermore, of the first through-hole 171A, only one of the diameters p1a of the portion that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and p2a of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125 may be larger than the diameter sa of the portion that penetrates the base layer 125.

[0288] In the capacitor-embedded substrate 101', if at least one of the diameters p1a of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and p2a of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125 is larger than the diameter sa of the portion that penetrates the base layer 125, then, as shown in Figure 19, a first through-hole 171A is provided on at least the inner wall surface of the first through-hole 171A. The outer shape of the first through-conductor 170A is such that at least one of the parts extending in the thickness direction from the base layer 125 to the anode layer 120A provided on the first surface 125a of the base layer 125, and the part extending in the thickness direction from the base layer 125 to the anode layer 120A provided on the second surface 125b of the base layer 125, bulges outward (protrudes) in a direction intersecting the thickness direction (for example, a direction perpendicular to the thickness direction) (for example, a stepped shape). Therefore, in the capacitor-embedded substrate 101', the contact area between the base layer 125 and the first through-conductor 170A tends to increase due to the bulging portion of the outer shape of the first through-conductor 170A as described above. Thus, in the capacitor-embedded substrate 101', the increased contact area between the base layer 125 and the first through-conductor 170A makes it easier for the base layer 125 and the first through-conductor 170A to adhere closely together due to the anchoring effect, etc., and as a result, the base layer 125 and the first through-conductor 170A become less likely to separate.

[0289] In the first through-hole 171A, the diameter qa of the portion that penetrates the first part 161a of the insulating layer 160 and the diameter sa of the portion that penetrates the base layer 125 may be the same as or different from each other. In the latter case, the diameter qa of the portion that penetrates the first part 161a of the insulating layer 160 may be larger than or smaller than the diameter sa of the portion that penetrates the base layer 125.

[0290] In the first through-hole 171A, the diameter ra of the portion that penetrates the second portion 161b of the insulating layer 160 and the diameter sa of the portion that penetrates the base layer 125 may be the same as or different from each other. In the latter case, the diameter ra of the portion that penetrates the second portion 161b of the insulating layer 160 may be larger than or smaller than the diameter sa of the portion that penetrates the base layer 125.

[0291] The capacitor-integrated circuit board 101' shown in Figure 19 is the same as the capacitor-integrated circuit board 101 shown in Figure 5, except for the configuration described above.

[0292] The capacitor-embedded substrate 101' shown in Figure 19 is manufactured in the same manner as the capacitor-embedded substrate 101 shown in Figure 5, except that a base layer 125 is provided.

[0293] Unlike the capacitor-embedded substrate 101' shown in Figure 19, at least one of the diameters p1a of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and p2a of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125 may be the same as the diameter sa of the portion that penetrates the base layer 125.

[0294] Figure 20 is a schematic cross-sectional view showing a capacitor-embedded substrate, which is an embodiment of the metal layer embedded substrate shown in Figure 18, and is a different example from that shown in Figure 19.

[0295] In the capacitor-embedded substrate 101'' shown in Figure 20, the first through conductor 170A constitutes the through conductor 70b shown in Figure 18. The first through hole 171A constitutes the through hole 71b shown in Figure 18.

[0296] In the capacitor-embedded substrate 101'', at least one of the diameters of the first through-hole 171A, specifically the diameter p1b of the portion that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and the diameter p2b of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125, is larger than the diameter qb of the portion that penetrates the first portion 161a of the insulating layer 160 and the diameter rb of the portion that penetrates the second portion 161b of the insulating layer 160. In the example shown in Figure 20, both the diameter p1b of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125, and the diameter p2b of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125, are larger than the diameter qb of the portion that penetrates the first portion 161a of the insulating layer 160, and the diameter rb of the portion that penetrates the second portion 161b of the insulating layer 160.

[0297] Furthermore, of the first through-hole 171A, only one of the diameters p1b of the portion that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and p2b of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125 may be larger than the diameter qb of the portion that penetrates the first portion 161a of the insulating layer 160 and the diameter rb of the portion that penetrates the second portion 161b of the insulating layer 160.

[0298] In the capacitor-embedded substrate 101'', at least one of the diameters p1b of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and p2b of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125 may be different from the diameter sb of the portion that penetrates the base layer 125. For example, in the capacitor-embedded substrate 101'', at least one of the diameters p1b of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and p2b of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125 may be smaller than the diameter sb of the portion that penetrates the base layer 125. In the example shown in Figure 20, both the diameter p1b of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125, and the diameter p2b of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125, are smaller than the diameter sb of the portion that penetrates the base layer 125.

[0299] In addition, of the first through-hole 171A, only one of the diameters p1b of the portion that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and p2b of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125 may be smaller than the diameter sb of the portion that penetrates the base layer 125.

[0300] In the capacitor-embedded substrate 101'', if at least one of the diameters p1b of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and p2b of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125 is smaller than the diameter sb of the portion that penetrates the base layer 125, then, as shown in Figure 20, a first through-hole 171A is provided on at least the inner wall surface of the first through-hole 171A. The outer shape of the first through-conductor 170A is such that at least one of the following parts—the part extending in the thickness direction from the anode layer 120A provided on the first surface 125a of the base layer 125 across the base layer 125, and the part extending in the thickness direction from the anode layer 120A provided on the second surface 125b of the base layer 125 across the base layer 125—is bulging outward in a direction intersecting the thickness direction (for example, a direction perpendicular to the thickness direction) (for example, a stepped shape). Therefore, in the capacitor-embedded substrate 101'', the contact area between the anode layer 120A and the first through-conductor 170A tends to increase due to the bulging portion of the outer shape of the first through-conductor 170A as described above. Thus, in the capacitor-embedded substrate 101'', the increased contact area between the anode layer 120A and the first through-conductor 170A makes it easier for the anode layer 120A and the first through-conductor 170A to adhere closely together due to the anchoring effect, and as a result, the anode layer 120A and the first through-conductor 170A become less likely to separate.

[0301] The capacitor-integrated circuit board 101'' shown in Figure 20 is the same as the capacitor-integrated circuit board 101' shown in Figure 19, except for the configuration described above.

[0302] The capacitor-embedded substrate 101'' shown in Figure 20 is manufactured in the same manner as the capacitor-embedded substrate 101 shown in Figure 5, except that when forming the first through-hole 171A, after providing the base layer 125, the diameter of the portion penetrating the base layer 125 is made wider than the diameter of the portion penetrating the anode layer 120A by, for example, removing the base layer 125 by a chemical treatment such as etching or removing the base layer 125 by a physical treatment such as polishing.

[0303] Unlike the capacitor-embedded substrate 101'' shown in Figure 20, at least one of the diameters p1b of the portion of the first through-hole 171A that penetrates the anode layer 120A provided on the first surface 125a of the base layer 125 and p2b of the portion that penetrates the anode layer 120A provided on the second surface 125b of the base layer 125 may be the same as the diameter sb of the portion that penetrates the base layer 125.

[0304] The metal layer embedded substrate of the present invention is not limited to the above-described form, and various applications and modifications can be made within the scope of the present invention regarding the structure, manufacturing conditions, etc., of the metal layer embedded substrate.

[0305] Although a capacitor-embedded substrate was shown above as an embodiment of the metal layer embedded substrate of the present invention, the metal layer embedded substrate of the present invention is not limited to a capacitor-embedded substrate. In other words, in the metal layer embedded substrate of the present invention, the core portion is not limited to a capacitor. In the metal layer embedded substrate of the present invention, the core portion may be, for example, various elements other than a capacitor, or it may be the metal layer itself.

[0306] In the above, when the metal layer embedded substrate of the present invention is a capacitor-embedded substrate, an electrolytic capacitor (here, a solid electrolytic capacitor) was shown as an example of a capacitor embedded in the capacitor-embedded substrate. However, the capacitor embedded in the capacitor-embedded substrate is not limited to an electrolytic capacitor. The capacitor embedded in the capacitor-embedded substrate may be, for example, a ceramic capacitor using barium titanate, a thin-film capacitor using silicon nitride, silicon dioxide, hydrogen fluoride, etc., or a trench-type capacitor having a MIM (Metal Insulator Metal) structure.

[0307] 1, 1' Metal layer embedded substrate 10 Core portion 10a First main surface of core portion 10b Second main surface of core portion 20, 20a, 20b Metal layer 25 Base layer 25a First surface of base layer 25b Second surface of base layer 60A First insulating layer 60B Second insulating layer 70, 70a, 70b Through conductor 71, 71a, 71b Through hole 80 Filling portion 90A First conductor layer 90B Second conductor layer 101, 101', 101'' Capacitor embedded substrate 110 Capacitor 110a First main surface of capacitor 110b Second main surface of capacitor 120 First electrode layer 120A Anode layer 121 Core portion 121a First surface of core portion 121b Second surface of core portion 122 Porous portion 125 Base layer 125a First surface of base layer 125b Second surface of base layer 130 Dielectric layer 140 Second electrode layer 140A Cathode layer 141 Solid electrolyte layer 142 Conductor layer 143 Conductive resin layer 144 Metal layer 150 Insulating mask layer 160 Insulating layer 161a First part of insulating layer 161b Second part of insulating layer 170A First through conductor 170B Second through conductor 171A First through hole 171B Second through hole 180A First filling part 180B Second filling part 190A First conductor layer 190B Second conductor layer 191A, 191B Conductor layer 195A, 195B Via conductor 171A', 196A, 196B, 271 Through hole P, P1a, P1b, P2a, P2b: Diameter of the portion of the through-hole that penetrates the metal layer. Q, Qa, Qb: Diameter of the portion of the through-hole that penetrates the first insulating layer. R, Ra, Rb: Diameter of the portion of the through-hole that penetrates the second insulating layer. Sa, Sb: Diameter of the portion of the through-hole that penetrates the base layer. p, p1a, p1b, p2a, p2b: Diameter of the portion of the first through-hole that penetrates the anode layer. q, qa, qb: Diameter of the portion of the first through-hole that penetrates the first part of the insulating layer. r, ra, rb: Diameter of the portion of the first through-hole that penetrates the second part of the insulating layer. sa, sb: Diameter of the portion of the first through-hole that penetrates the base layer.

Claims

1. A metal layer embedded substrate comprising: a core portion having a first main surface and a second main surface opposite to each other in the thickness direction and including a metal layer; a first insulating layer provided on the first main surface of the core portion; a second insulating layer provided on the second main surface of the core portion; and a through conductor provided on at least the inner wall surface of a through hole that penetrates the core portion, the first insulating layer, and the second insulating layer in the thickness direction, wherein the diameter of the portion of the through hole that penetrates the metal layer is larger than the diameter of the portion that penetrates the first insulating layer and the diameter of the portion that penetrates the second insulating layer.

2. The metal layer embedded substrate according to claim 1, wherein the core portion further includes a base layer having a pair of surfaces opposite to each other in the thickness direction, and the metal layer is provided on at least one of the pair of surfaces of the base layer.

3. The metal layer embedded substrate according to claim 2, wherein the diameter of the portion of the through hole that penetrates the metal layer is different from the diameter of the portion that penetrates the base layer.

4. The metal layer embedded substrate according to claim 3, wherein the diameter of the portion of the through hole that penetrates the metal layer is larger than the diameter of the portion that penetrates the base layer.

5. The metal layer embedded substrate according to claim 3, wherein the diameter of the portion of the through hole that penetrates the metal layer is smaller than the diameter of the portion that penetrates the base layer.

6. The metal layer embedded substrate according to any one of claims 1 to 5, wherein the core portion includes a capacitor having a first electrode layer, a dielectric layer, and a second electrode layer facing the first electrode layer via the dielectric layer in the thickness direction, and the first electrode layer constitutes the metal layer.

7. The metal layer embedded substrate according to claim 6, wherein the first electrode layer is an anode layer comprising a core portion having a pair of surfaces opposite to each other in the thickness direction and a porous portion provided on at least one of the pair of surfaces of the core portion, the dielectric layer is provided on the surface of the porous portion, and the second electrode layer is a cathode layer provided on the surface of the dielectric layer.

8. The metal layer embedded substrate according to any one of claims 1 to 7, further comprising a first conductor layer provided on the surface of the first insulating layer opposite to the core portion and electrically connected to the through conductor.

9. The metal layer embedded substrate according to claim 8, further comprising a second conductor layer provided on the surface of the second insulating layer opposite to the core portion and electrically connected to the through conductor.

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