Wiring board

Abstract

This wiring board comprises a core substrate, a hole part, a component positioned in the hole part, and a resin positioned around the component and filling the hole part. The hole part has a sidewall, and the sidewall has a first section, one end of which is positioned on a first surface, and a second section contiguous with the first section. If the angle in a direction perpendicular to the first surface is 90 degrees and the angle of inclination in which the width of the hole part gradually increases toward the first surface is 0-90 degrees in a vertical cross section, the angle of the sidewall in the first section is referred to as a1, and the angle of the sidewall in the second section is referred to as a2, then the expressions a1<a2 and a1<90 degrees are satisfied. When a region extending from the peripheral edge of a first opening to the outside of the first opening on the first surface is referred to as a first region, the resin is positioned in the first region and inside the hole part.

Description

Wiring board

[0001] This disclosure relates to a wiring board.

[0002] Japanese Patent Publication No. 2010-129992 shows a wiring board in which components are housed in holes in a core material, and which has wiring stacking sections on the upper and lower sides of the core material.

[0003] A wiring board according to one embodiment of the present disclosure comprises: a core substrate having a first surface and a second surface located opposite to the first surface; a hole located on the core substrate and having a first opening on at least the first surface; a component located in the hole; a resin located around the component and filling the hole; a first build-up layer laminated on the first surface side of the core substrate; and a second build-up layer laminated on the second surface side of the core substrate, wherein the hole has a side wall, the side wall has a first section with one end located on the first surface, and a second section following the first section, and in a longitudinal cross-section, 90 degrees is defined as the angle perpendicular to the first surface, and 0 to 90 degrees is defined as the angle of inclination in which the width of the hole gradually widens toward the first surface, and when the angle of the side wall in the first section is called a1 and the angle of the side wall in the second section is called a2, then a1 < a2 and a1 < 90 degrees, When the region extending from the periphery of the first opening outward on the first surface is called the first region, the resin is located in both the pore and the first region.

[0004] A wiring board according to another aspect of the present disclosure includes: a core substrate having a first surface and a second surface located opposite the first surface; a hole located in the core substrate, the hole having a first opening on the first surface and a second opening on the second surface; a component located in the hole; a resin located around the component and filling the hole; a first build-up layer stacked on the first surface side of the core substrate; and a second build-up layer stacked on the second surface side of the core substrate, wherein the hole has a side wall, the side wall has a third section and a fourth section continuing from the third section with one end located at the second surface, in a longitudinal cross-section, when 90 degrees is defined as the angle in the direction perpendicular to the first surface, an angle between 0 degrees and 90 degrees is defined as the angle of an inclination where the width of the hole gradually increases toward the first surface, the angle of the side wall of the third section is denoted as a3, and the angle of the side wall of the fourth section is denoted as a4, a4 < a3, and a4 < 90 degrees.

[0005] It is a cross-sectional view showing the wiring board according to Embodiment 1 of the present disclosure. It is an enlarged view of the vicinity of the upper portion of the hole in Fig. 1. A cross-sectional view of the hole in Comparative Example 1 is shown. A cross-sectional view of the hole in Comparative Example 2 is shown. It is an enlarged view of the vicinity of the upper portion of the hole in Fig. 1. An enlarged view of the vicinity of the lower portion of the hole in Fig. 1 is shown. It is an enlarged view of the vicinity of the lower portion of the hole in Fig. 1. It is a view of several points in the vicinity of the lower portion of the hole in Fig. 1 as viewed from below. It is an extracted view of a part of Fig. 6A. It is a longitudinal cross-sectional view showing the wiring board according to Embodiment 2. It is an enlarged view of the vicinity of the lower portion of the hole in Embodiment 2. It is a view for explaining the method of manufacturing the wiring board according to the embodiment.

[0006] Hereinafter, embodiments will be described with reference to the drawings. However, the dimensions of members in each drawing do not faithfully represent the actual dimensions and dimensional ratios of the constituent members. In the following description, the direction perpendicular to the first surface S1 of the core substrate 2 is referred to as the vertical direction, and the direction along the first surface S1 is referred to as the horizontal direction. This direction may be different from the direction when the wiring board 1 is in use. In the following, viewing or seeing through from a direction perpendicular to the first surface S1 is referred to as "plan view". In addition, the "longitudinal cross-section" means a cross-section when cut along a plane perpendicular to the first surface S1.

[0007] (Embodiment 1) Figure 1 is a cross-sectional view of a wiring board 1 according to Embodiment 1. The wiring board 1 may comprise a core substrate 2 holding a component 5, and a first build-up layer 3 and a second build-up layer 4 laminated on the core substrate 2. The wiring board 1 may have more build-up layers laminated on it. The wiring board 1 may also be called a component-embedded build-up substrate or a component-embedded printed wiring board.

[0008] The core substrate 2 has a first surface S1 and a second surface S2 located on the opposite side of the first surface S1, and may be in the shape of a plate. The core substrate 2 may have an insulating layer 21, a hole 22 in which the component 5 is located, a via conductor 23, and a land 24. The material of the insulating layer 21 may be a resin, a mixture of resin and an inorganic filler, a resin containing a fibrous reinforcing material, or the above mixture containing a fibrous reinforcing material. The via conductor 23 may be a conductor located in a through hole extending from the first surface S1 to the second surface S2. In the figure, a configuration is shown in which the conductor is located throughout the through hole, but the via conductor 23 may be configured in which the conductor is located in a hollow cylindrical shape. The land 24 is a layered conductor located on the first surface S1 and the second surface S2, and may be connected to one end of the via conductor 23. The material of the via conductor 23 and the land 24 may be a metal such as copper.

[0009] The hole 22 may have a first opening 221 on at least the first surface S1. The hole 22 may further have a second opening 222 on the second surface S2 by penetrating the insulating layer 21.

[0010] The first build-up layer 3 is laminated on the first surface S1 side of the core substrate 2 and may have an insulating layer 31 and a via conductor 32. The insulating layer 31 is in the form of a plate, and the material of the insulating layer 31 may be a resin, a mixture of resin and an inorganic filler, a resin containing a fibrous reinforcing material, or the above mixture containing a fibrous reinforcing material. One end of the via conductor 32 may be connected to a land 24 on the core substrate 2 or the first electrode 52 of the component 5. A land 33 may be located at the other end of the via conductor 32. The material of the via conductor 32 and the land 33 may be a metal such as copper.

[0011] The second build-up layer 4 is laminated on the second surface S2 side of the core substrate 2 and may have an insulating layer 41 and a via conductor 42. The insulating layer 41 is in the form of a plate, and the material of the insulating layer 41 may be a resin, a mixture of resin and an inorganic filler, a resin containing a fibrous reinforcing material, or the above mixture containing a fibrous reinforcing material. One end of the via conductor 42 may be connected to a land 24 on the core substrate 2 or a second electrode 53 on the component 5. A land 43 may be located at the other end of the via conductor 42. The material of the via conductor 42 and the land 43 may be a metal such as copper.

[0012] Component 5 may be an electronic component, an electrical component such as a capacitor, or a component other than electronics and electrical components. Component 5 may have a block-shaped substrate 51. The periphery of the substrate 51 may be an insulator. The substrate 51 may have a third surface S511 facing the first build-up layer 3 and a fourth surface S512 facing the second build-up layer 4. Component 5 may further have one or more first electrodes 52 located on the third surface S511. Component 5 may further have one or more second electrodes 53 located on the fourth surface S512.

[0013] The wiring board 1 may further have a resin 6 positioned around the component 5 and filling the holes 22. The resin 6 may be a variety of curing types, such as a thermosetting resin, an ultraviolet curing resin, or a resin that hardens over time. The resin 6 may also be called a filler resin.

[0014] <Details of Hole 22 1> Figure 2 is an enlarged view of the upper area of ​​the hole 22 (i.e., the upper part C1 in Figure 1). The hole 22 may have a side wall 223. The side wall 223 may be a wall that surrounds the hole 22 from the horizontal direction. The side wall 223 may have a first section Z1 with one end located on the first surface S1, and a second section Z2 that follows the first section Z1. The second section Z2 may be located above the center in the vertical direction of the side wall 223 (see Figure 7). Furthermore, in the vertical section, the angle a1 of the side wall 223 in the first section Z1 and the angle a2 of the side wall 223 in the second section Z2 may have the following relationship (1).

[0015] a1 < a2, and a1 < 90 degrees... (1) However, the angle is defined as 90 degrees in the direction perpendicular to the first surface S1, and the angle of inclination from 0 degrees to 90 degrees in which the width of the hole 22 gradually widens toward the first surface S1.

[0016] According to the above configuration of the hole portion 22, the first opening 221 can be enlarged while keeping the increase in the volume of the hole portion 22 low. The enlargement of the first opening 221 makes it easier to insert the component 5 into the hole portion 22 during the manufacturing stage, and also makes it easier to fill the hole portion 22 with resin 6.

[0017] Figures 3A and 3B show cross-sectional views of hole 91 in Comparative Example 1 and hole 92 in Comparative Example 2, respectively. In Comparative Example 1, hole 91 has the same size as the first opening 911, while the side wall 913 is made vertical. In Comparative Example 2, hole 92 has the same size as the first opening 921, while the side wall 923 is inclined at the same angle from the first surface S1 to the second surface S2.

[0018] According to the hole portion 22 of Embodiment 1, the clearance b1 (see Figure 3A) between the hole portion 22 and the component 5 can be reduced compared to the hole portion 91 of Comparative Example 1. Therefore, it is easier to reduce the misalignment of the component 5. Furthermore, in the hole portion 91 of Comparative Example 1, the first electrode 52 of the component 5 may come close to the edge of the first opening 911. Therefore, in order to reduce the occurrence of a short circuit with the via conductor 23 of the core substrate 2, it is difficult to bring the via conductor 23 close to the first opening 911. On the other hand, according to the hole portion 22 of Embodiment 1, the first electrode 52 of the component 5 is less likely to come close to the edge of the first opening 221 compared to the hole portion 91 of Comparative Example 1. Therefore, the via conductor 23 can be brought closer to the first opening 221. Therefore, the degree of freedom of wiring of the core substrate 2 is improved.

[0019] Furthermore, in the hole 92 of Comparative Example 2, the volume of the space 92a1 between the side wall 923 and the part 5 is large, so the flatness of the resin 6 tends to decrease at the upper interface of the space 92a1. In addition, because the angle of the side wall 923 is close to vertical, a meniscus-like depression is likely to occur in the resin 6 before curing at the upper interface of the space 92a1, and therefore a depression is likely to occur in the resin 6 after curing. On the other hand, in the hole 22 of Embodiment 1, the volume of the space 22a1 (see Figure 4) between the side wall 223 and the part 5 is smaller compared to the hole 92 of Comparative Example 2. Furthermore, the angle a1 of the side wall 223 in the first section Z1 (see Figure 2) is closer to horizontal compared to the side wall 923 of Comparative Example 2. Therefore, the flatness of the resin 6 can be improved even at the upper interface of the space 22a1 (see Figure 4) between the side wall 223 and the part 5. Note that in Comparative Example 1, a depression is also likely to occur in the resin 6. Therefore, compared to the hole portion 91 in Comparative Example 1, the hole portion 22 of Embodiment 1 can improve the flatness of the resin 6.

[0020] Furthermore, in the first embodiment, the volume of the hole 22 is smaller than that of the second comparative example. That is, the volume removed from the core substrate 2 by the hole 22 is smaller. For example, the core substrate 2 in the first embodiment has a larger volume in the region 92a2 shown in Figure 3B. And in the first embodiment, it is possible to provide wiring in the region 92a2 as well, thus improving the wiring flexibility of the core substrate 2.

[0021] As shown in Figure 2, in the wiring board 1 of Embodiment 1, the resin 6 located around the component 5 may be located in a first region X1 on the first surface S1 that extends outward from the edge q1 of the first opening 221 to the first opening 221. The resin 6 located in the first region X1 may be sandwiched between the core substrate 2 and the first build-up layer 3. The resin 6 located in the first region X1 may be continuous with the resin 6 located in the hole 22.

[0022] With this configuration, the resin 6 located in the first region X1 can smooth the resin 6 located in the first opening 221. That is, when filling the first opening 221 with resin 6, even a slight error in the amount of resin 6 can easily cause irregularities on the surface of the resin 6 in the first opening 221. However, the error in the amount of resin 6 can be absorbed by the resin 6 overflowing into the first region X1. Therefore, the resin in the first opening 221 can be smoothed. Consequently, the flatness of the first surface S1 of the core substrate 2, including the first opening 221, can be improved. By improving the flatness of the first surface S1, the flatness of the first build-up layer 3 and the upper surface of the wiring board 1 is improved. Therefore, when electronic components such as integrated circuits are mounted on the upper surface of the wiring board 1, the advantage of improved mountability of electronic components can be obtained. This effect is achieved whether or not there is a slope configuration in the first section Z1 and the second section Z2, and the third section Z3 and the fourth section Z4 described later.

[0023] Furthermore, the positioning of the resin 6 in the first region X1 provides the advantage that, during the manufacturing stage of the wiring board 1, after the resin 6 is cured and the component 5 is fixed to the hole 22, the component 5 can be firmly held. Specifically, during the manufacturing stage of the wiring board 1, after the resin 6 is cured and the component 5 is fixed to the hole 22, an unexpected external force may be applied to the first opening 221 or the second opening 222 of the hole 22. In such a case, with the conventional configuration, the resin 6 may peel off by sliding along the side wall 223, potentially releasing the component 5. On the other hand, the positioning of the resin 6 in the first region X1 adds the adhesive force of the first region X1 to the adhesive force between the core substrate 2 and the resin 6. Furthermore, since the first region X1 is a region that extends outward from the periphery of the first opening 221, even if the width in the expanding direction is small, it has a relatively large area because it is long in the circumferential direction. Therefore, a large adhesive force can be obtained as the adhesive force of the first region X1. Furthermore, in situations where the resin 6 is attempting to peel off in a sliding direction along the side wall 223, generally, the presence of a bent portion on the adhesive surface can reduce the peeling of the resin 6 by providing resistance from the bent portion. In the configuration of Embodiment 1, the bent portion is a relatively sharply bent edge q1 between the resin 6 located in the first region X1 and the resin 6 extending inward into the hole 22. Therefore, greater resistance can be obtained from this edge q1. The large resistance at this edge q1, combined with the adhesive force of the large area of ​​the first region X1, provides the advantage of strengthening the retention of the part 5 by the hole 22 during the manufacturing stage.

[0024] <Details of Hole 22 2> The resin 6 that has spread into the first region X1 may overlap with at least a part of the first land 24A in a plan view. The first land 24A refers to the land 24 located near the first opening 221 among the lands 24 located on the first surface S1. With this configuration, a stronger adhesive force can be obtained from the resin 6 in the portion that overlaps with the first land 24A. Therefore, the advantage is obtained that the holding of the part 5 by the hole 22 during the manufacturing stage can be made stronger. This effect is achieved whether or not there is an inclined configuration of the first section Z1 and the second section Z2, and the third section Z3 and the fourth section Z4 which will be described later.

[0025] Figure 4 is an enlarged view of the area around the upper part of the hole 22 (i.e., the upper part C1 in Figure 1). In the vertical direction, the third surface S511 of the part 5 may be located above the position P11 which is halfway along the side wall 223 of the first section Z1.

[0026] With this configuration, the thickness T62 of the resin 6 filling the part 5 can be made thinner than the thickness T61 of the resin 6 filling the relatively wide space 22a1 created by the inclination of the side wall 223 at angle a1. For example, when filling the resin 6 from the first surface S1 side by printing, if there is a wide area where a large amount of resin 6 is required, it becomes difficult to control the supply amount of resin 6, and fluctuations are likely to occur on the surface of the filled resin 6. However, as in the above configuration, by having the space 22a1 where a large amount of resin is required and the upper part of the part 5 where a small amount of resin is required adjacent to each other, it is possible to sufficiently fill the space 22a1 with resin 6 and easily flatten the surface of the filled resin 6 from the space 22a1 to the part 5. Therefore, the flatness of the first surface S1 of the core substrate 2, including the upper part of the hole 22, can be further improved.

[0027] As shown in Figure 4, the length L1 of the first section Z1 in the vertical direction may be 100 μm or less. Alternatively, the length L1 may be 2% or more and 10% or less of the thickness T2 of the core substrate 2 (see Figure 1). This configuration makes it easy to insert the component 5 into the hole 22 while reducing the volume of the relatively large space 22a1 created by the inclination of the side wall 223 of the first section Z1. Therefore, the flatness of the first surface S1 of the core substrate 2, including the upper part of the hole 22, can be further improved.

[0028] As shown in Figure 2, the angle a2 of the side wall 223 of the second section Z2 may have the following relationship: (90 degrees - 5 degrees) < a2 < (90 degrees + 5 degrees) ... (2) With this configuration, if the base body 51 of the component 5 is rectangular or cylindrical, and the side surface S513 extends at an angle nearly perpendicular to the fourth surface S512, the second section Z2 can be made to follow the side surface S513 of the base body 51. With this structure, the component 5 can be stably placed in the hole 22.

[0029] <Details of Hole 22 3> Figure 5 shows an enlarged view of the lower part of the hole 22 (i.e., the lower part C2 in Figure 1). The side wall 223 of the hole 22 may have a third section Z3 and a fourth section Z4 that is continuous with the third section Z3 and has one end located on the second surface S2. The third section Z3 may be located below the center in the vertical direction of the side wall 223. In the vertical section, the angle a3 of the side wall 223 of the third section Z3 and the angle a4 of the side wall 223 of the fourth section Z4 may have the following relationship (3).

[0030] a4 < a3 and a4 < 90 degrees... (3) However, the angle is defined as 90 degrees in the direction perpendicular to the first surface S1 (see Figure 1), and the angle from 0 degrees to 90 degrees is the angle of inclination in which the width of the hole 22 gradually widens toward the first surface S1.

[0031] With this configuration, the inclined side wall 223 of the fourth section Z4 makes the width of the second opening 222 smaller than the width of the hole 22 of the third section Z3. Therefore, when one end of the part 5 faces the second opening 222, the position of the part 5 is easily determined. Thus, misalignment of the part 5 in the hole 22 is less likely to occur. Furthermore, as shown in Figures 2 and 5, the width of the hole 22 is widest at the first opening 221, and the width narrows from the first section Z1 to the fourth section Z4, with the second opening 222 being the narrowest. Therefore, a structure is realized in which it is easy to insert the part 5 into the hole 22 from the first opening 221, and it is difficult for the part 5 to fall out from the second opening 222.

[0032] Furthermore, with the hole 22 having the side walls 223 of the third section Z3 and the fourth section Z4, the volume of the hole 22 can be reduced compared to the hole 92 of Comparative Example 2 in Figure 3B. That is, when the size of the hole 22 is set so that components 5 of the same size can be placed, the volume of the hole 22 in Embodiment 1 can be reduced compared to the volume of the hole 92 in Comparative Example 2. For example, the core substrate 2 of Embodiment 1 has a larger volume in the areas 92a3 and 92a4 shown in Figure 3B. And in Embodiment 1, it is possible to provide wiring in the areas 92a3 and 92a4, thus improving the wiring flexibility of the core substrate 2.

[0033] As shown in Figure 5, the angle a3 of the side wall 223 of the third section Z3 may have the following relationship: (90 degrees - 5 degrees) < a3 < (90 degrees + 5 degrees) ... (4) With this configuration, if the base 51 of the component 5 is rectangular or cylindrical, and the side surface S513 of the component 5 extends at an angle nearly perpendicular to the fourth surface S512, the third section Z3 can be made to follow the side surface S513 of the base 51. With this structure, the component 5 can be stably placed in the hole 22.

[0034] As shown in Figures 2 and 5, the angle a1 of the side wall 223 of the first section Z1 and the angle a4 of the side wall 223 of the fourth section Z4 may have the following relationship (5): a1 < a4 ... (5) With this configuration, when filling the hole 22 with resin 6, the bending resistance of the movement path of the resin 6 from the first surface S1 side to the underside of the part 5 via the side of the part 5 can be reduced. Therefore, filling with resin 6 becomes easier. Note that angles a1 and a4 may be the same.

[0035] <Details of Hole 22 4> Figures 6A to 6C are enlarged views of the lower area of ​​Hole 22 (specifically, lower C2 in Figure 1), views of several points in the lower area from below, and views of a portion of the area, respectively.

[0036] The base 51 of component 5 may have a first side surface S513a located closest to the side wall 223 of the third section Z3. When the first corners P1 to the third corners P3 in the same longitudinal section are viewed from below, the second corner P2 may be located between the first corner P1 and the third corner P3, as shown in Figure 6B.

[0037] The first corner P1 is the lower end corner of the first side surface S513a. The second corner P2 is the corner where the side wall 223 of the fourth section Z4 in the core substrate 2 intersects with the second surface S2. The third corner P3 is the corner of the lower end surface of the second electrode 53 in the component 5 that is closest to the side wall 223 (however, the side wall 223 on the same side as the second corner P2).

[0038] With this configuration, when the lower end surface of the second electrode 53 of the component 5 is viewed from below in a vertical cross-section, the entire lower end surface can be contained within the second opening 222. Therefore, connection between the second electrode 53 and the via conductor 42 of the second build-up layer 4 becomes easier. Furthermore, with this configuration, it is possible to create a state in which the base body 51 of the component 5 is less likely to pass through the second opening 222. Therefore, the component 5 is less likely to fall out of the hole 22 from before the resin 6 is filled into the hole 22 until the resin 6 hardens. In addition, since the lower part of the base body 51 is positioned near the second opening 222, the positional variation of the component 5 from product to product can be reduced. Therefore, handling of the component 5 becomes easier in the manufacturing process of the wiring board 1.

[0039] <Details of Hole 22 5> As shown in Figure 5, the resin 6 located around the component 5 may be located in a second region X2 on the second surface S2 that extends outward from the edge q2 of the second opening 222 to the second opening 222. The resin 6 located in the second region X2 may be sandwiched between the core substrate 2 and the second build-up layer 4. The resin 6 located in the second region X2 may be continuous with the resin 6 located in the hole 22.

[0040] With this configuration, the resin 6 located in the second region X2 can smooth out the resin 6 occupying the second opening 222. That is, when filling the second opening 222 with resin 6, even slight errors in the amount of resin 6 can easily cause irregularities on the surface of the resin 6 in the second opening 222. However, the excess resin 6 overflowing into the second region X2 can absorb these errors in the amount of resin 6. Therefore, the resin 6 in the second opening 222 can be smoothed out. Consequently, the flatness of the second surface S2 of the core substrate 2 including the second opening 222 can be improved. By improving the flatness of the second surface S2, the flatness of the second build-up layer 4 and the lower surface of the wiring board 1 is improved. Therefore, when electronic components are mounted on the lower surface of the wiring board 1, or when the lower surface of the wiring board 1 is mounted on another substrate, the advantage of improved mountability can be obtained.

[0041] Furthermore, the positioning of the resin 6 in the second region X2 provides the advantage that, during the manufacturing stage of the wiring board 1, after the resin 6 is cured and the component 5 is fixed to the hole 22, the component 5 can be firmly held. Specifically, during the manufacturing stage of the wiring board 1, after the resin 6 is cured and the component 5 is fixed to the hole 22, an unexpected external force may be applied to the second opening 222 or the first opening 221 of the hole 22. In such a case, with the conventional configuration, the resin 6 may peel off by sliding along the side wall 223, potentially releasing the component 5. On the other hand, by positioning the resin 6 in the second region X2, not only is the adhesive force of the second region X2 added to the adhesive force between the core substrate 2 and the resin 6, but the lower end of the core substrate 2 also acts as a stopper, reducing the likelihood of the component 5 and resin 6 falling out. Moreover, since the second region X2 is a region that extends outward from the periphery of the second opening 222, even if the width in the expanding direction is small, it is long in the circumferential direction and therefore has a relatively large area. Therefore, a large adhesive force can be obtained as the adhesive force of the second region X2. Furthermore, because there is a fourth section Z4 with the angle a4 described above, the occurrence of voids when filling with resin 6 can be reduced. As a result, the effect of reducing peeling of resin 6 is enhanced.

[0042] Furthermore, in situations where the resin 6 is attempting to peel off in a sliding direction along the side wall 223, generally, the presence of a bent portion on the adhesive surface can reduce the likelihood of the resin 6 peeling off due to the resistance exerted by this bent portion. In the configuration of Embodiment 1, the bent portion is a relatively sharply bent edge q2 between the resin 6 located in the second region X2 and the resin 6 extending inward into the hole 22. Therefore, greater resistance can be obtained from this edge q2. The large resistance at this edge q2, combined with the adhesive force of the large area of ​​the second region X2, provides the advantage of strengthening the retention of the part 5 by the hole 22 during the manufacturing stage.

[0043] Although not shown in the figure, the resin 6 spreading to the second region X2 may overlap at least a part of the second land 24B in a plan view. The second land 24B refers to the land 24 located on the second surface S2 that is positioned near the second opening 222. According to this configuration, a stronger adhesive force can be obtained by the portion of the resin 6 overlapping the second land 24B. Therefore, the advantage that the holding of the component 5 by the hole 22 in the manufacturing stage can be made stronger is obtained.

[0044] <Details of Hole 22, Part 6> As shown in FIG. 6A, the base body 51 of the component 5 may include a lower end surface S514 intersecting the first corner P1, a step portion 515 located between the lower end surface S514 and the fourth surface S512, a second side surface S513b which is a side surface of the step portion 515, and a fourth corner P4 where the second side surface S513b and the fourth surface S512 intersect. Then, as shown in FIG. 6C, the angle a5 of the line segment E1 connecting the first corner P1 and the fourth corner P4 in the same longitudinal section and the angle a4 of the side wall 223 of the fourth section Z4 may satisfy the relationship of the following formula (6). -60 degrees < a5 - a4 < 30 degrees (6) The relationship of formula (6) means that the angle a5 of the line segment E1 is close to the angle a4 of the side wall 223 of the fourth section Z4.

[0045] According to this configuration, even if the thickness of the second electrode 53 is small, the side surface S513 of the base body 51 can be brought close to the side wall 223 of the hole 22 while reducing interference between the side wall 223 of the fourth section Z4 and the base body 51. That is, the ratio of the volume of the base body 51 to the volume of the hole 22 can be increased. Therefore, even when the component 5 with a large volume is employed, the volume of the hole 22 is less likely to become excessively large. That is, the amount by which the volume of the core substrate 2 is reduced due to the hole 22 can be reduced, thereby increasing the wiring flexibility of the core substrate 2.

[0046] As shown in FIGS. 6A and 6C, in the vertical direction, the boundary q3 between the third section Z3 and the fourth section Z4 may be located above the first corner P1. According to this configuration, it is easy to arrange the component 5 along the fourth section Z4, and it becomes easy to control the position of the component 5.

[0047] The wiring substrate 1 may have the structure shown in FIG. 1 in a longitudinal cross-section at any position of the hole 22. Alternatively, the wiring substrate 1 may not have a part of the structure shown in FIG. 1 in a longitudinal cross-section at some positions. Even with this configuration, the operational effects of the aforementioned structure can be obtained at positions having the structure shown in FIG. 1 in the longitudinal cross-section.

[0048] (Embodiment 2) FIG. 7A is a longitudinal cross-sectional view showing a wiring substrate 1A of Embodiment 2. FIG. 7B is an enlarged view of the periphery of the lower part of the hole of Embodiment 2 (that is, the lower part C2A). In the wiring substrate 1A of Embodiment 2, the shape of the base body 51A of the component 5 is different from that of Embodiment 1, and other components may be the same as those of Embodiment 1. The base body 51A of the component 5 does not have the stepped portion 515 shown in Embodiment 1, and as shown in FIG. 7B, the intersection of the side surface S513 (corresponding to the first side surface S513a) and the fourth surface S512 is the first corner P1.

[0049] In the wiring substrate 1A of Embodiment 2, the structures of details 1 to 5 of the aforementioned hole 22 are similarly provided, and the operational effects of the constituent elements are similarly exhibited. The wiring substrate 1A may have the structure shown in FIG. 7A in a longitudinal cross-section at any position of the hole 22. Alternatively, the wiring substrate 1A may not have a part of the structure shown in FIG. 7A in a longitudinal cross-section at some positions. Even with this configuration, the operational effects of the aforementioned structure can be obtained at positions having the structure shown in FIG. 7A in the longitudinal cross-section.

[0050] <Method for Manufacturing Wiring Substrate 1> FIG. 8 is a diagram illustrating an example of a method for manufacturing the wiring substrate 1 of Embodiment 1. The method for manufacturing the wiring substrate 1 may include: step J1 of forming a wiring conductor on a core substrate 2; step J2 of forming a hole 22 in an insulating layer 21; step J3 of loading the component 5 into the hole 22; and step J4 of filling the hole 22 with a resin 6 and curing the resin 6. The method may further include step J5 of forming a first build-up layer 3 and a second build-up layer 4 on the first surface S1 side and the second surface S2 side of the core substrate 2 to which the component 5 is fixed. For steps J1 and J5, corresponding steps of a conventional method for manufacturing a build-up substrate may be applied.

[0051] For machining the hole 22 in step J2, cutting using a router drill, for example, may be applied. This cutting process can form side walls 223 with different inclination angles in the first section Z1 to the fourth section Z4. If the hole 22 penetrates the insulating layer 21, a carrier tape 81 is temporarily attached to the second surface in order to mount the component 5.

[0052] When inserting part 5 in process J3, the angle a1 of the inclination of the side wall 223 in the first section Z1 of the hole 22 allows for easy insertion of part 5. Furthermore, the angles a2 to a3 (see Figures 2 and 5) of the side wall 223 in the second section Z2 to the fourth section Z4 make it easier to determine the position of part 5 within the hole 22, thereby reducing misalignment of part 5 from product to product.

[0053] The filling of the resin 6 in step J4 may be achieved, for example, by screen printing. During printing, the resin may spread slightly beyond the opening of the screen mask and be transferred to the core substrate 2. Screen printing may be performed on the first surface S1 side, and the resin 6 may fill the holes 22 by flowing around the part 5 from the first surface S1 side to the second surface S2 side. The part 5 is fixed to the holes 22 of the core substrate 2 as the resin 6 hardens. After that, the carrier tape 81 that was temporarily attached is peeled off.

[0054] Then, in step J5, the first build-up layer 3 and the second build-up layer 4 are formed, thereby manufacturing the wiring board 1 of Embodiment 1. The wiring board 1A of Embodiment 2 can also be manufactured by the same method.

[0055] The embodiments of this disclosure have been described above. However, the wiring boards of this disclosure are not limited to the wiring boards 1 and 1A of the above embodiments. For example, in the above embodiments, an example was shown in which the hole 22 also opens to the second surface S2, but the hole 22 may open only to the first surface S1. Also, in the above embodiments, an embodiment was shown that has both the structure of the side wall 223 of the first section Z1 and second section Z2 at angles a1 and a2, and the structure of the side wall 223 of the third section Z3 and fourth section Z4 at angles a3 and a4, but it may have only one of these structures. Furthermore, the details shown in the embodiments can be appropriately modified without departing from the spirit of the invention.

[0056] An embodiment of the present disclosure is shown below. In one embodiment, (1) the wiring board comprises: a core substrate having a first surface and a second surface located opposite to the first surface; a hole located on the core substrate and having a first opening on at least the first surface; a component located in the hole; a resin located around the component and filling the hole; a first build-up layer laminated on the first surface side of the core substrate; and a second build-up layer laminated on the second surface side of the core substrate, wherein the hole has a side wall, the side wall has a first section with one end located on the first surface and a second section following the first section, and in a longitudinal cross-section, when 90 degrees is defined as the angle perpendicular to the first surface and 0 to 90 degrees is defined as the angle of inclination in which the width of the hole gradually widens toward the first surface, the angle a1 of the side wall in the first section and the angle a2 of the side wall in the second section are a1 < a2 and a1 < 90 degrees, When the region extending from the periphery of the first opening outward on the first surface is called the first region, the resin is located in both the pore and the first region.

[0057] (2) The wiring board described in (1) further comprises a first land located on the first surface, wherein the resin located in the first region in a plan view overlaps with at least a portion of the first land.

[0058] (3) The wiring board according to (1) or (2) above, wherein the component comprises a substrate having a third surface facing the first build-up layer and a first electrode located on the third surface, and in a direction perpendicular to the first surface, the third surface is located above half of the first section.

[0059] (4) Any one of the wiring boards described in (1) to (3) above has a length of the first section in a direction perpendicular to the first surface of 100 μm or less, or a length of 2% or more and 10% or less of the thickness of the core substrate.

[0060] (5) The wiring board comprises: a core substrate having a first surface and a second surface located opposite to the first surface; a hole located on the core substrate having a first opening on the first surface and a second opening on the second surface; a component located in the hole; a resin located around the component and filling the hole; a first build-up layer laminated on the first surface side of the core substrate; and a second build-up layer laminated on the second surface side of the core substrate, wherein the hole has a side wall, the side wall has a third section and a fourth section that is continuous with the third section and has one end located on the second surface, and in a longitudinal cross section, when 90 degrees is defined as the angle perpendicular to the first surface and 0 to 90 degrees is defined as the angle of inclination in which the width of the hole gradually widens toward the first surface, the angle a3 of the side wall in the third section and the angle a4 of the side wall in the fourth section are a4 < a3 and a4 < 90 degrees.

[0061] (6) The wiring board described in (5) above further comprises a base having a fourth surface facing the second build-up layer, a second electrode located on the fourth surface, and a first surface located closest to the side wall of the third section in a longitudinal cross-section, wherein in a longitudinal cross-section the component has a first corner located at the lower end of the first surface, in a longitudinal cross-section the core substrate has a second corner where the side wall of the fourth section and the second surface intersect, in a longitudinal cross-section the component has a third corner closest to the side wall among the lower corners of the second electrode, and when viewed from below, the second corner is located between the first corner and the third corner.

[0062] (7) The wiring board described in (6) above has a base body having a lower end surface that intersects the first corner, a stepped portion located between the lower end surface and the fourth surface, a second side surface which is the side surface of the stepped portion, and a fourth corner where the second side surface and the fourth surface intersect in a vertical cross-section, and in a vertical cross-section, the angle a5 of the line segment connecting the fourth corner and the first corner is -60 degrees < a5 - a4 < 30 degrees.

[0063] (8) In the wiring board of (6) or (7) above, the boundary between the third section and the fourth section is located above the first corner.

[0064] (9) Any one of the wiring boards described in (1) to (4) above, wherein the hole portion further has a second opening on the second surface, and the side wall has a third section and a fourth section that is continuous with the third section and has one end on the second surface, and in a longitudinal section, 90 degrees is defined as the angle perpendicular to the first surface, and 0 to 90 degrees is defined as the angle of inclination in which the width of the hole portion gradually widens toward the first surface, and the angle of the side wall of the third section is called a3, and the angle of the side wall of the fourth section is called a4, then a4 < 90 degrees and a4 < a3.

[0065] (10) The wiring board in (9) above has a1 < a4.

[0066] (11) The wiring boards in (9) or (10) above satisfy the following conditions: (90 degrees - 5 degrees) < a2 < (90 degrees + 5 degrees) and (90 degrees - 5 degrees) < a3 < (90 degrees + 5 degrees).

[0067] (12) In any one of the wiring boards described in (9) to (11) above, when the region extending from the periphery of the second opening outward on the second surface is called the second region, the resin is located in the hole and in the second region.

[0068] This disclosure can be used in wiring boards.

[0069] 1, 1A Wiring board 2 Core board 22 Hole 221 First opening 222 Second opening q1, q2 Edge 223 Side wall Z1 First section Z2 Second section Z3 Third section Z4 Fourth section q3 Boundary a1-a5 Angle 24A First land 24B Second land S1 First surface X1 First region S2 Second surface X2 Second region 3 First build-up layer 4 Second build-up layer 5 Components 51, 51A Substrate 515 Step 52 First electrode 53 Second electrode S511 Third surface S512 Fourth surface S513 Side S513a First side S513b Second side S514 Bottom surface E1 Line segment 6 Resin P1 First corner P2 Second corner P3 3rd corner P4 4th corner

Claims

1. A core substrate having a first surface and a second surface located opposite the first surface; a hole located in the core substrate and having a first opening in at least the first surface; a component located in the hole; a resin located around the component and filling the hole; a first build-up layer laminated on the first surface side of the core substrate; and a second build-up layer laminated on the second surface side of the core substrate, wherein the hole has a side wall, the side wall has a first section with one end located on the first surface and a second section following the first section, and in a longitudinal cross-section, when 90 degrees is defined as the angle perpendicular to the first surface and 0 to 90 degrees is defined as the angle of inclination in which the width of the hole gradually widens toward the first surface, the angle a1 of the side wall in the first section and the angle a2 of the side wall in the second section are a1 < a2 and a1 < 90 degrees, When the region extending from the periphery of the first opening outward on the first surface is called the first region, the resin is a wiring substrate located in the hole and the first region.

2. The wiring board according to claim 1, further comprising a first land located on the first surface, wherein the resin overlaps with at least a portion of the first land in a plan view.

3. The wiring board according to claim 1 or claim 2, wherein the component comprises a substrate having a third surface facing the first build-up layer, and a first electrode located on the third surface, wherein the third surface is located above half of the first section in a direction perpendicular to the first surface.

4. The wiring board according to any one of claims 1 to 3, wherein the length of the first section in a direction perpendicular to the first surface is 100 μm or less, or 2% or more and 10% or less of the thickness of the core substrate.

5. A wiring board comprising: a core substrate having a first surface and a second surface located opposite the first surface; a hole located on the core substrate having a first opening on the first surface and a second opening on the second surface; a component located in the hole; a resin located around the component and filling the hole; a first build-up layer laminated on the first surface side of the core substrate; and a second build-up layer laminated on the second surface side of the core substrate, wherein the hole has a side wall, the side wall having a third section and a fourth section that is continuous with the third section and has one end located on the second surface, and in a longitudinal cross-section, when 90 degrees is defined as the angle perpendicular to the first surface and 0 to 90 degrees is defined as the angle of inclination in which the width of the hole gradually widens toward the first surface, the angle a3 of the side wall in the third section and the angle a4 of the side wall in the fourth section are a4 < a3 and a4 < 90 degrees.

6. The wiring board according to claim 5, wherein the component further comprises a substrate having a fourth surface facing the second build-up layer, a second electrode located on the fourth surface, and a first surface located closest to the side wall of the third section in a longitudinal cross-section, wherein the component has a first corner located at the lower end of the first surface in a longitudinal cross-section, the core substrate has a second corner where the side wall of the fourth section and the second surface intersect in a longitudinal cross-section, the component has a third corner closest to the side wall among the lower corners of the second electrode in a longitudinal cross-section, and the second corner is located between the first corner and the third corner when viewed from below.

7. The substrate has a lower end surface intersecting the first corner, a stepped portion located between the lower end surface and the fourth surface, a second side surface which is the side surface of the stepped portion, and a fourth corner where the second side surface and the fourth surface intersect in a longitudinal cross-section, wherein in a longitudinal cross-section, the angle a5 of the line segment connecting the fourth corner and the first corner is -15 degrees < a5 - a4 < 15 degrees, the wiring board according to claim 6.

8. The wiring board according to claim 6 or claim 7, wherein the boundary between the third section and the fourth section is located above the first corner.

9. The wiring board according to any one of claims 1 to 4, wherein the hole further has a second opening on the second surface, the side wall has a third section and a fourth section that is continuous with the third section and has one end located on the second surface, and in a longitudinal cross-section, 90 degrees is defined as the angle perpendicular to the first surface, and 0 to 90 degrees is defined as the angle of inclination in which the width of the hole gradually widens toward the first surface, and the angle of the side wall of the third section is called a3, and the angle of the side wall of the fourth section is called a4, such that a4 < 90 degrees and a4 < a3.

10. The wiring board according to claim 9, wherein a1 < a4.

11. The wiring board according to claim 9 or claim 10, wherein (90 degrees - 5 degrees) < a2 < (90 degrees + 5 degrees) and (90 degrees - 5 degrees) < a3 < (90 degrees + 5 degrees).

12. When the region extending outward from the periphery of the second opening on the second surface is called the second region, the resin is located in the hole and in the second region, as described in any one of claims 9 to 11.

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