Wiring board and electronic device

Abstract

This wiring board comprises: a plate-shaped insulating substrate having a first board surface; and a wiring conductor positioned inside and on a surface of the insulating substrate. The first board surface has a mounting region for an electronic component, and a first raised region and a second raised region that have raised portions respectively positioned on one side and the other side of the mounting region.

Description

Wiring board and electronic device

[0001] The present disclosure relates to a wiring board and an electronic device.

[0002] Japanese Patent Application Laid-Open No. 2021-011411 describes a wiring substrate using a ceramic sintered body. The wiring substrate is applied to a package on which a semiconductor element or the like is mounted.

[0003] The wiring board according to the present disclosure comprises a flat insulating base having a first plate surface, and wiring conductors located inside and on the surface of the insulating base, wherein the first plate surface has a mounting area for electronic components, and a first convex area and a second convex area having protrusions located on either side of the mounting area.

[0004] An electronic device according to the present disclosure includes the above wiring board and an electronic component mounted on the wiring board.

[0005] FIG. 1B is a plan view showing a wiring board according to a first embodiment of the present disclosure. FIG. 1A is a cross-sectional view taken along line B1-B1 of FIG. 1A. FIG. 1B is an enlarged cross-sectional view showing a portion of the wiring board of FIG. 1A. FIG. 1C is a plan view showing a wiring board according to a second embodiment of the present disclosure. FIG. 1D is a cross-sectional view showing a wiring board according to a third embodiment of the present disclosure. FIG. 1E is a cross-sectional view showing a wiring board according to a fourth embodiment of the present disclosure. FIG. 1F is a cross-sectional view showing a wiring board according to a fifth embodiment of the present disclosure. FIG. 1G is a cross-sectional view showing a wiring board according to a sixth embodiment of the present disclosure. FIG. 1H is a cross-sectional view taken along line B2-B2 of FIG. 7A. FIG. 1J is a plan view showing a wiring board according to a seventh embodiment of the present disclosure. FIG. 1J is a cross-sectional view taken along line B3-B3 of FIG. 8A. FIG. 1J is a plan view showing a wiring board according to an eighth embodiment of the present disclosure. FIG. 1J is a cross-sectional view taken along line B4-B4 of FIG. 9A. FIG. 1J is a cross-sectional view taken along line C1-C1 of FIG. 9A. FIG. 1J is a plan view showing a wiring board according to a ninth embodiment of the present disclosure. FIG. 1J is a cross-sectional view taken along line B5-B5 of FIG. 10A. FIG. 1J is a cross-sectional view taken along line C2-C2 of FIG. 10A. FIG. 1J is a plan view showing a wiring board according to a tenth embodiment of the present disclosure. FIG. 1J is a cross-sectional view taken along line B6-B6 of FIG. 11A. FIG. 1J is a cross-sectional view taken along line C3-C3 of FIG. 11A. 11A is a cross-sectional view taken along line D1-D1 in Fig. 11A; Fig. 12A is a plan view showing a wiring board according to an eleventh embodiment of the present disclosure; Fig. 13A is a cross-sectional view taken along line B7-B7 in Fig. 12A; Fig. 13A is a cross-sectional view taken along line C4-C4 in Fig. 12A; Fig. 14A is a cross-sectional view showing an electronic device according to an embodiment of the present disclosure.

[0006] Each embodiment of the present disclosure will be described in detail below with reference to the drawings. In this embodiment, the direction perpendicular to the first surface 11 of the wiring board 1 is referred to as the height direction, and two directions perpendicular to the height direction and perpendicular to each other are referred to as the horizontal direction (corresponding to the first direction) and the vertical direction (corresponding to the second direction). Furthermore, in a plan view of the wiring board 1, one horizontal direction and the other horizontal direction are referred to as the left and the right. These directions may differ from the directions when the wiring board 1 is in use. In the cross-sectional views in the drawings, unevenness in the thickness and height directions is exaggerated. Wiring conductors are not shown in the cross-sectional views except in FIG. 2.

[0007] 1A is a plan view showing a wiring board 1 according to a first embodiment of the present disclosure. Fig. 1B is a cross-sectional view taken along line B1-B1 in Fig. 1A. Fig. 2 is an enlarged cross-sectional view of the wiring board 1 in Fig. 1.

[0008] The wiring board 1 according to the first embodiment of the present disclosure includes a flat insulating base 10 having a first plate surface 11, and wiring conductors 20 located inside and on the surface of the insulating base 10. The wiring board 1 may further include a second plate surface 12 located opposite the first plate surface 11.

[0009] The wiring board 1 may be a large board having a vertical and horizontal width of 50 mm to 150 mm, 60 mm to 120 mm, or 70 mm to 90 mm. The thickness of the wiring board 1 may be 0.5 mm to 10 mm, 1 mm to 5 mm, or 1.5 mm to 2.5 mm.

[0010] The insulating base 10 is a fired product having insulating properties, such as ceramics, etc. The insulating base 10 may be glass ceramics.

[0011] The first plate surface 11 may be rectangular with first to fourth sides 11a to 11d extending vertically and horizontally as shown in the figure, or may be polygonal, such as a convex polygon, or may have curved portions on some or all of the sides, although this is not shown. If rectangular, the first plate surface 11 may be a rectangle close to a square, with a height / width ratio of 1 / 1.2 to 1.2 / 1 in plan view. The first plate surface 11 has a mounting area 111 on which electronic components are mounted, and a first convex area 112 and a second convex area 113 located on either side of the mounting area 111.

[0012] 2 , the wiring conductor 20 has a plurality of pad portions 21 located on the first plate surface 11 or the second plate surface 12, a plurality of film conductors 22 extending in a direction along the first plate surface 11 within the wiring board 1, and a plurality of via conductors 23 extending in a direction intersecting the first plate surface 11 within the wiring board 1. The wiring conductor 20 is a conductor whose main component is copper, and may be configured to be fired together with the insulating base 10. The main component means a component that accounts for 80% or more by mass.

[0013] The mounting area 111 may be an area where a plurality of pads 21 (omitted in the plan view) corresponding to a plurality of terminals of an electronic component such as an integrated circuit are located. The electronic component is mounted in the mounting area 111 so that the plurality of terminals of the electronic component are electrically connected to the plurality of pads 21, respectively.

[0014] The mounting area 111 may be rectangular in shape, with its vertical width greater than its horizontal width, or may be square in shape. The mounting area 111 may be a region having a protrusion on the first plate surface 11. The protrusion may have a trapezoidal cross section. The trapezoidal shape is a concept that includes shapes that are distorted from a strict trapezoid, such as a trapezoid with rounded corners or a trapezoid whose upper side is not a strict straight line.

[0015] The mounting area 111 may be located in a central range of the first plate surface 11. Located in the central range may mean, for example, that the mounting area 111 is located so that the majority of the mounting area 111 overlaps with the central range of the first plate surface 11 divided horizontally into thirds. Also, located in the central range may mean, for example, that the mounting area 111 is located so that the majority of the mounting area 111 overlaps with the central range of the first plate surface 11 divided vertically into thirds. Most means ¾ or more.

[0016] The areas on the first plate surface 11 other than the mounting area 111 are areas where major electronic components such as integrated circuits are not mounted, and may be areas where the proportion of pad portions 21 located is small (for example, zero) compared to the mounting area 111.

[0017] Many of the pads 21 located in the mounting area 111 may be electrically connected to the pads 21 on the second plate surface 12 through the film conductors 22 and via conductors 23 inside the wiring conductor 20. On the first plate surface 11, the pads 21 may be arranged in the mounting area 111 at a first density, while on the second plate surface 12, the pads 21 may be arranged in an area larger than the mounting area 111 at a second density lower than the first density.

[0018] The first convex region 112 and the second convex region 113 are regions that bulge in the height direction. When the thickness of the insulating base 10 is 1 mm to 10 mm, the amount of bulge may be 10 μm to 200 μm, 20 μm to 100 μm, or 30 μm to 50 μm. The amount of bulge may be set so that the ratio of "bulge amount / thickness" is the same depending on the thickness of the insulating base 10. The amount of bulge refers to the difference in height from the lowest point at the base of the region boundary to the highest point in the region.

[0019] The first convex region 112 and the second convex region 113 may have a trapezoidal cross section and may have a shape in plan view that has a width and a length that are approximately the same (e.g., 50% to 200%) as those of the mounting region 111. The first convex region 112 and the second convex region 113 may have a shape that is elongated vertically in plan view.

[0020] The width of the first convex region 112 can be measured as follows. That is, the portion around the first convex region 112 where the height of the first plate surface 11 changes more sharply than other regions is defined as the edge of the first convex region 112. The locus connecting half the height points of the portion where the height changes sharply in the planar direction is defined as the boundary of the first convex region. The length between two points where a line segment extending horizontally in a planar view overlaps with the boundary of the first convex region 112 can be defined as the width. If the width of the first convex region 112 is not constant across locations, measurements can be taken uniformly at multiple locations, and the average value can be used as the representative width. The vertical width can be determined by performing similar measurements in the vertical direction. The same applies to the horizontal and vertical widths of the second convex region 113.

[0021] The first convex region 112 may be located away from the periphery of the first plate surface 11 (e.g., the first side 11a to the third side 11c) and away from the mounting region 111. In other words, a surface lower in height than the first convex region 112 may be located all around the first convex region 112. The first convex region 112 may be a region that partially contacts the periphery of the first plate surface 11 (e.g., the second side 11b on the left side). In this case, the raised portion of the first convex region 112 continues to the periphery of the first plate surface 11 at the portion that contacts the second side 11b.

[0022] The second convex region 113 may be located away from the periphery of the first plate surface 11 (e.g., the third side 11c, the fourth side 11d, and the first side 11a) and away from the mounting region 111. In other words, a surface lower in height than the second convex region 113 may be located around the entire periphery of the second convex region 113. The second convex region 113 may be a region that partially contacts the periphery of the first plate surface 11 (e.g., the fourth side 11d on the right side). In this case, the raised portion of the first convex region 112 continues to the periphery of the first plate surface 11 at the portion contacting the second side 11b.

[0023] On the first plate surface 11, the areas excluding the mounting area 111, the first convex area 112, and the second convex area 113 may contain relatively small irregularities, but may be lower than the first convex area 112 and the second convex area 113.

[0024] EXAMPLES Next, a specific wiring board 1 was produced, and the results of evaluating the warpage of the wiring board 1 will be described.

[0025] First, a mixture of 40 wt % alumina particles and 60 wt % borosilicate glass was prepared as the material for the insulating base 10. This mixture is a glass ceramic raw material with a firing temperature of 900°C to 1000°C. 20 parts by mass of isobutyl methacrylate resin and dibutyl phthalate were used as the organic binder for 100 parts by mass of the glass ceramic raw material, and multiple green sheets measuring 90 mm x 80 mm and 50 μm and 75 μm in thickness were produced by doctor blade molding.

[0026] Copper powder with an average particle size of 2 μm and silica particles with an average particle size of 20 nm were prepared as raw materials for the wiring conductor 20. The proportion of the integrated amount of silica particles with a lower limit of 10 nm and an upper limit of 30 nm was 70% or more. The amount of silica particles added was 1 part by mass per 100 parts by mass of copper powder. Furthermore, isobutyl methacrylate resin and a mixed solvent of butyl carbitol acetate and dibutyl phthalate were used as the organic binder. A conductor paste containing copper powder and silica particles was prepared by adding 5 parts by mass of isobutyl methacrylate resin per 100 parts by mass of copper powder and further adding a mixed solvent of butyl carbitol acetate and dibutyl phthalate.

[0027] Conductive paste that would become pad portions 21 and film-like conductors 22 was printed in a predetermined arrangement on both surfaces of the prepared green sheet, and through holes were formed between the two surfaces at predetermined positions of the green sheet, and the through holes were filled with conductive paste that would become via conductors 23. A vertically long rectangular mounting area 111 was set in the center of the first plate surface 11, and film-like conductors 22 and via conductors 23 were formed so that multiple pad portions 21 were located in the mounting area.

[0028] Furthermore, a pre-fired material was prepared by stacking a plurality of green sheets containing the conductive paste so that the first convex region 112 and the second convex region 113 could be raised on the wiring board 1. The thickness of the pre-fired material was set to 2 mm.

[0029] The prepared pre-fired material was fired in a reducing atmosphere using a hydrogen-nitrogen mixed gas at a maximum temperature of 930° C. for a holding time of 2 hours.

[0030] When the warpage of the wiring board 1 after firing was measured, it was confirmed that the second plate surface 12 had multiple warps in the horizontal direction, with the direction reversing midway like a valley-peak, valley-peak, valley pattern, and that the deviation from the flat shape was smaller compared to a configuration in which the entire board was warped in one direction.

[0031] As described above, according to the wiring board 1 of the first embodiment, stress in the warping direction occurs in the wiring board 1 due to factors such as the difference in the thermal expansion coefficients between the insulating base 10 and the wiring conductor 20. However, the presence of the first convex region 112 and the second convex region 113 reduces the likelihood of the wiring board 1 warping in the same direction with the same curvature from one end to the other. As a specific example, multiple warps occur on the second plate surface 12, with the direction reversing midway, like a valley-peak, valley-peak, valley-peak pattern. Therefore, even for a large wiring board 1, a wiring board 1 with a small deviation from a flat plate shape can be provided compared to a case in which the entire wiring board 1 warps in the same direction.

[0032] 3 is a plan view showing a wiring board 1A according to a second embodiment of the present disclosure. The wiring board 1A of the second embodiment differs in the configuration of a mounting region 111A on which electronic components are mounted in a plan view, but the other components may be the same as those of the first embodiment.

[0033] 3, the first plate surface 11 may include a plurality of mounting areas 111Aa, 111Ab. The plurality of mounting areas 111Aa, 111Ab may be aligned vertically so that most of them overlap in the central area of ​​the first plate surface 11. By virtually filling in the portions between the plurality of mounting areas 111Aa, 111Ab, when the plurality of mounting areas 111Aa, 111Ab are viewed as a single mounting area 111A, the mounting area 111A may have a shape in which the vertical width is greater than the horizontal width. A plurality of electronic components may be mounted in each of the plurality of mounting areas 111Aa, 111Ab.

[0034] Although not shown in the drawings, the first plate surface 11 may have three or more mounting areas located in a nearby range, and three or more electronic components may be mounted on each of the mounting areas.

[0035] The wiring board 1A of embodiment 2 also provides the same effect as embodiment 1. Furthermore, even in the case of a large wiring board 1A, it is possible to provide a wiring board 1A that has a small deviation from a flat plate shape compared to a case in which the entire wiring board 1A warps in the same direction.

[0036] 4 is a plan view showing a wiring board 1B according to a third embodiment of the present disclosure. The wiring board 1B of the third embodiment differs from the first and second embodiments in that the arrangement direction of the first convex region 112 and the second convex region 113 is specified, but the other components may be the same as those of either the first or second embodiment.

[0037] 4, the size of the area surrounding the mounting area 111 may be different in the vertical and horizontal directions on the first surface 11 of the wiring board 1B. Specifically, the horizontal distance X1 from the mounting area 111 to the edge of the first surface 11 may be longer than the vertical distance Y1 from the mounting area 111 to the edge of the first surface 11 (i.e., X1 > Y1). In this case, the area surrounding the mounting area 111 is larger in the horizontal direction than in the vertical direction.

[0038] The first convex region 112, the mounting region 111, and the second convex region 113 may be aligned in a direction in which the region surrounding the mounting region 111 is larger (horizontal direction in the case of FIG. 4).

[0039] The size of the area surrounding the mounting area 111 varies depending on the aspect ratio of the mounting area 111 and the aspect ratio of the overall dimensions of the insulating base 10. The aspect ratio means the ratio of vertical width to horizontal width. In the example of FIG. 4 , the insulating base 10 has a larger vertical width than horizontal width, and the mounting area 111 has a larger vertical width than horizontal width. Therefore, the insulating base 10 is closer to a square than the mounting area 111, so the distance X1 is greater than the distance Y1. However, even in a configuration in which the aspect ratios of the insulating base 10 and the mounting area 111 are different from those in the example of FIG. 4 , the first convex area 112 and the second convex area 113 may be arranged on the larger side of the distance X1 and the distance Y1.

[0040] In general wiring boards in which the mounting area is located in the central range, warping is likely to occur in the area surrounding the mounting area that is larger. According to wiring board 1B of embodiment 3, first convex area 112 and second convex area 113 are aligned in the above-mentioned direction, which reduces warping of the entire wiring board 1B in the same direction in the direction in which warping is likely to occur, and makes it possible to provide wiring board 1B with small deviation from a flat plate shape.

[0041] 5 is a plan view showing a wiring board 1C according to a fourth embodiment of the present disclosure. The wiring board 1C of the fourth embodiment differs from the first to third embodiments in that the relationship between the vertical width of the mounting region 111 and the vertical widths of the first convex region 112 and the second convex region 113 is specified, but the other components may be the same as any of the first to third embodiments.

[0042] In the description of the fourth embodiment, the mounting area 111, the first convex area 112, and the second convex area 113 are arranged in the horizontal direction. If the arrangement direction is the vertical direction, the horizontal and vertical directions in the following description may be interchanged.

[0043] 5, the vertical widths Y12, Y13 of the first convex region 112 and the second convex region 113 may be greater than the vertical width Y11 of the mounting region 111. Furthermore, both ends E11, E12 of the mounting region 111 may be located closer to the center in the vertical direction than the ends of the first convex region 112 and the second convex region 113.

[0044] As described above, the first convex region 112 and the second convex region 113 act to reduce warping in the same direction throughout the entire area of ​​the wiring substrate 1C, from one end to the other in the horizontal direction. Therefore, while this effect is strong in the region Ey1 where the first convex region 112 and the second convex region 113 are located in the vertical direction, this effect may be weaker in the other regions Ey2 and Ey3. Therefore, by setting the vertical width of the first convex region 112 and the second convex region 113 as in the wiring substrate 1C of embodiment 4, this effect is also strong in the regions E1 to E4 at the four corners of the mounting region 111. Therefore, warping of the mounting region 111 can be further reduced.

[0045] 6 is a plan view showing a wiring board 1D according to a fifth embodiment of the present disclosure. The wiring board 1D of the fifth embodiment differs from the first to fourth embodiments in that the relationship between the width of the mounting region 111 and the widths of the first convex region 112 and the second convex region 113 is specified, but the other components may be the same as any of the first to fourth embodiments.

[0046] In the description of the fourth embodiment, the mounting area 111, the first convex area 112, and the second convex area 113 are arranged in the horizontal direction. If the arrangement direction is the vertical direction, the horizontal and vertical directions in the following description may be interchanged.

[0047] 6, the width X22 of the first convex region 112 and the width X23 of the second convex region 113 may be approximately the same as the width X21 of the mounting region 111. Approximately the same means 0.8 to 1.2 times.

[0048] Varying the widths of the first convex region 112 and the second convex region 113 can change the strength of the effect of reducing warping of the entire wiring board 1D in the same direction in the horizontal direction, as well as the position where the warping direction changes from peak to peak on the second board surface 12 of the wiring board 1D. Therefore, depending on the width setting, relatively large warping may occur near the center of the mounting area 111. However, by setting the widths X21 to X23 as in the wiring board 1D of embodiment 5, warping can be reduced throughout the entire horizontal area of ​​the mounting area 111, further improving the flatness of the mounting area 111. This configuration is more useful for stably mounting electronic components in the mounting area 111.

[0049] Sixth Embodiment Fig. 7A is a plan view showing a wiring board 1E according to a sixth embodiment of the present disclosure. Fig. 7B is a cross-sectional view taken along line B2-B2 in Fig. 7A. The wiring board 1E of the sixth embodiment differs from the first to fifth embodiments in that the relationship between the height of the mounting region 111 and the heights of the first convex region 112 and the second convex region 113 is specified, but the other components may be the same as any of the first to fifth embodiments.

[0050] 7B , the height h1 of the mounting region 111 may be smaller than the height h2 of the first convex region 112 and the height h3 of the second convex region 113. In other words, the height of the mounting region 111 may be smaller than the heights of the first convex region 112 and the second convex region 113. The height refers to the height when the wiring substrate 1E is placed on a flat surface and the flat surface is used as a reference surface.

[0051] Even if the first convex region 112 and the second convex region 113 have the effect of reversing the direction of warpage of the wiring board 1E midway, adjusting the magnitude and arrangement of this effect can change the magnitude of warpage in the central region Ex1 in the lateral direction. Furthermore, if the warpage in the central region Ex1 is made relatively large, the mounting region 111 becomes higher due to the warpage on the convex side. However, by adjusting the height of the mounting region 111 to be lower, as in the wiring board 1E of embodiment 6, the warpage in the central region Ex1 of the wiring board 1E becomes relatively small, and the flatness of the mounting region 111 can be further improved. This configuration is more useful for stably mounting electronic components in the mounting region 111.

[0052] Seventh Embodiment Fig. 8A is a plan view showing a wiring board 1F according to a seventh embodiment of the present disclosure. Fig. 8B is a cross-sectional view taken along line B3-B3 in Fig. 8A. The wiring board 1F of the seventh embodiment differs from the first to fifth embodiments in that the relationship between the height of the mounting region 111 and the heights of the first convex region 112 and the second convex region 113 is specified, but the other components may be the same as any of the first to fifth embodiments.

[0053] 8B , the height h11 of the mounting region 111 may be greater than the height h12 of the first convex region 112 and the height h13 of the second convex region 113. In other words, the height of the mounting region 111 may be greater than the heights of the first convex region 112 and the second convex region 113. The height refers to the height when the wiring substrate 1F is placed on a flat surface and the flat surface is used as a reference surface.

[0054] Even if the first convex region 112 and the second convex region 113 have the effect of reversing the direction of warpage of the wiring board 1F midway, adjusting the magnitude and position of this effect can change the magnitude of warpage in the regions Ex2 and Ex3 near the edges in the lateral direction. Furthermore, if the warpage in the regions Ex2 and Ex3 near the edges is relatively small, the mounting region 111 becomes higher due to the warpage on the convex side of the central region Ex1. On the other hand, the overall flatness of the second plate surface 12 can be improved accordingly. Therefore, according to the wiring board 1F of embodiment 7, the flatness of the second plate surface 12 can be improved, thereby improving the secondary mountability of the wiring board 1F. Secondary mountability refers to the ease of handling when mounting the wiring board 1F, on which electronic components are mounted, on a module substrate 210 (see FIG. 13 ) via the second plate surface 12.

[0055] Eighth Embodiment Fig. 9A is a plan view showing a wiring board 1G according to an eighth embodiment of the present disclosure. Fig. 9B is a cross-sectional view taken along line B4-B4 in Fig. 9A. Fig. 9C is a cross-sectional view taken along line C1-C1 in Fig. 9A. The wiring board 1G of the eighth embodiment differs in that the configuration of the edge portion of the first plate surface 11 is specified differently, and the other components may be the same as those of any of the first to seventh embodiments.

[0056] 9A, the first convex region 112 and the second convex region 113 may be located away from the edges (i.e., the first side 11a to the fourth side 11d) of the first plate surface 11. That is, there may be a low region to the left of the first convex region 112, and a low region to the right of the second convex region 113.

[0057] According to the wiring board 1G of embodiment 8, as shown in Figures 9B and 9C, the height of the edge portion 119 along the entire periphery of the first plate surface 11 can be reduced, thereby improving the flatness of the entire edge portion 119 along the entire periphery of the first plate surface 11. The wiring board 1G may be attached with a shield case 130 (see Figure 13) that shields the mounting area 111. According to the wiring board 1G of embodiment 8, the improved flatness of the edge portion 119 improves the attachability of the shield case 130 via the edge portion 119. This configuration is particularly useful when the entire periphery of the edge portion 119 is joined to the frame portion at the lower end of the shield case 130 via solder or the like.

[0058] (Embodiment 9) Fig. 10A is a plan view showing a wiring board 1H according to embodiment 9 of the present disclosure. Fig. 10B is a cross-sectional view taken along line B5-B5 in Fig. 10A. Fig. 10C is a cross-sectional view taken along line C2-C2 in Fig. 10A. The wiring board 1H of embodiment 9 differs in that the configuration of the edge portion of the first plate surface 11 is specified differently, and other components may be similar to any of embodiments 1 to 7.

[0059] 10A , the first convex region 112 and the second convex region 113 may be in contact with the edges (specifically, the second side 11b on the left side and the fourth side 11d on the right side) of the first plate surface 11. That is, a portion of the second side 11b of the first plate surface 11 may be continuous with the high portion of the first convex region 112, and a portion of the fourth side 11d of the first plate surface 11 may be continuous with the high portion of the second convex region 113.

[0060] 10B and 10C , in wiring board 1H of embodiment 9, edge 119 along the entire periphery of first plate surface 11 has a height that differs between a portion of second side 11b and a portion of fourth side 11d and the remaining portion. When shield case 130 (see FIG. 13 ) is attached to wiring board 1H, the frame portion of the lower end of shield case 130 can be joined via solder or the like, except for the vicinity of a portion of second side 11b and a portion of fourth side 11d.

[0061] (Embodiment 10) Fig. 11A is a plan view showing a wiring board 1I according to embodiment 10 of the present disclosure. Fig. 11B is a cross-sectional view taken along line B6-B6 in Fig. 11A. Fig. 11C is a cross-sectional view taken along line C3-C3 in Fig. 11A. Fig. 11D is a cross-sectional view taken along line D1-D1 in Fig. 11A. The wiring board 1I according to embodiment 10 differs in the third convex region 114 and the fourth convex region 115, but the other components may be similar to any of embodiments 1 to 9.

[0062] As shown in FIG. 11A, the insulating base 10 may have a third convex region 114 and a fourth convex region 115 on one side and the other side of the mounting region 111 in the vertical direction on the first plate surface 11 .

[0063] The third convex region 114 and the fourth convex region 115 are regions that bulge in the height direction. When the thickness of the insulating base 10 is 1 mm to 10 mm, the amount of bulge may be 10 μm to 200 μm, 20 μm to 100 μm, or 30 μm to 50 μm. The amount of bulge may be set so that the ratio of "bulge amount / thickness" is the same depending on the thickness of the insulating base 10. The amount of bulge refers to the difference in height from the lowest point at the base of the region boundary to the highest point in the region.

[0064] The third convex region 114 and the fourth convex region 115 may have a trapezoidal cross section, and may be longer horizontally than vertically in a plan view.

[0065] The third convex region 114 may be located away from the periphery of the first plate surface 11 (e.g., the first side 11a), the mounting region 111, the first convex region 112, and the second convex region 113. In other words, a surface lower in height than the third convex region 114 may be located around the entire periphery of the third convex region 114. The third convex region 114 may be a region that partially contacts the periphery of the first plate surface 11 (e.g., the upper first side 11a). In this case, the raised portion of the third convex region 114 continues to the periphery of the first plate surface 11 at the portion contacting the first side 11a.

[0066] The fourth convex region 115 may be located away from the periphery of the first plate surface 11 (e.g., the third side 11c), the mounting region 111, the first convex region 112, and the second convex region 113. In other words, a surface lower in height than the fourth convex region 115 may be located all around the fourth convex region 115. The fourth convex region 115 may be a region that is partially in contact with the periphery of the first plate surface 11 (e.g., the lower third side 11c). In this case, the raised portion of the fourth convex region 115 continues to the periphery of the first plate surface 11 at the portion in contact with the third side 11c.

[0067] On the first plate surface 11, the areas excluding the mounting area 111 and the first convex area 112 to the fourth convex area 115 include relatively small irregularities, but may be lower than the first convex area 112 to the fourth convex area 115.

[0068] In a planar view, the first convex region 112 to the fourth convex region 115 may have a shape in which the width closer to the mounting region 111 is smaller than the width closer to the edge of the first plate surface 11, or, although not shown, any or all of them may be rectangular, polygonal, elliptical, or oval.

[0069] The first convex region 112 to the fourth convex region 115 have the effect of reducing warpage in both the vertical and horizontal directions. Therefore, the flatness of the mounting region 111 can be further improved in both the vertical and horizontal directions. In addition, the flatness of the second plate surface 12 can be further improved in both the vertical and horizontal directions.

[0070] (Embodiment 11) Fig. 12A is a plan view showing a wiring board 1J according to embodiment 11 of the present disclosure. Fig. 12B is a cross-sectional view taken along line B7-B7 in Fig. 12A. Fig. 12C is a cross-sectional view taken along line C4-C4 in Fig. 12A. The wiring board 1J of embodiment 4 differs in the configuration in the vertical direction from the mounting area 111, but the other components may be similar to any of embodiments 1 to 9.

[0071] As shown in Figures 12A to 12C, on the first plate surface 11, a first recessed area 116 and a second recessed area 117 may be located on either side of the mounting area 111 in the vertical direction of the mounting area 111.

[0072] The first recessed region 116 may be configured to be lower than the surrounding surfaces on the left, right, and mounting region 111 side, but higher than the edge 119 of the first plate surface 11. Furthermore, the side of the first recessed region 116 opposite the mounting region 111 may be gently sloping toward the lower edge 119, or may be substantially flat. The same applies to the second recessed region 117.

[0073] The first concave region 116 and the second concave region 117 strengthen the effect of reversing the direction of the lateral warpage caused by the first convex region 112 and the second convex region 113, thereby improving the vertical flatness of the mounting region 111. This configuration is particularly useful when the electronic component to be mounted is long in one direction and the mounting region 111 is longer vertically than horizontally. In the above case, high vertical flatness improves the mountability of the electronic component.

[0074] (Electronic Device) FIG. 13 is a cross-sectional view showing an electronic device 100 according to an embodiment of the present disclosure. The electronic device 100 of this embodiment includes the wiring board 1 shown in embodiment 1 and an electronic component 120 mounted on the mounting region 111. The electronic component 120 is an integrated circuit having a large number of terminals, but may also be various other types of electronic components. The electronic device 100 may further include a shielding case 130 joined to an edge 119 of the wiring board 1 via a joining material such as solder. The shielding case 130 may be made of metal and have a box shape with one open end, and the frame of the open end may be joined to the wiring board 1.

[0075] The electronic module 200 of this embodiment includes a module substrate 210 and an electronic device 100 mounted on the module substrate 210. In addition to the electronic device 100, various types of electronic components, electric components, and the like may be mounted on the module substrate 210.

[0076] The electronic device 100 has a large number of terminals (a specific example is pad portions 21) on the second plate surface 12 of the wiring board 1, and the large number of terminals may be joined to a large number of terminals of the module substrate 210 via a bonding material such as solder.

[0077] In the electronic device 100 and the electronic module 200, the wiring board 1 may be replaced with any of the wiring boards 1A to 1J of the other embodiments described above.

[0078] According to the electronic device 100 and the electronic module 200 of this embodiment, even if the wiring board 1 is large, the entire wiring board 1 is less likely to warp in the same direction. This can further improve the mountability of the electronic component 120 and the mountability between the wiring board 1 and the module substrate 210.

[0079] The above describes the embodiments of the present disclosure. However, the wiring board and electronic device of the present disclosure are not limited to the above embodiments. For example, the material of the insulating base of the wiring board is not limited to ceramics, and resin or the like may also be used. Other details shown in the embodiments can be modified as appropriate without departing from the spirit of the invention.

[0080] In one embodiment of the present disclosure, (1) a wiring board includes: a flat insulating base having a first plate surface; and wiring conductors located inside and on a surface of the insulating base, wherein the first plate surface has a mounting area for an electronic component, and a first convex area and a second convex area, each having a protrusion, located on one side and the other side of the mounting area.

[0081] (2) In the wiring board of (1) above, the distance between the mounting area and the edge of the first plate surface in a first direction along the first plate surface is longer than the distance between the mounting area and the edge of the first plate surface in a second direction perpendicular to the first direction and along the first plate surface, and the first convex area, the mounting area, and the second convex area are aligned in the first direction.

[0082] (3) In the wiring board of (1) or (2) above, the first convex region, the mounting region, and the second convex region are aligned in a first direction, and in a second direction perpendicular to the first direction and along the first plate surface, the length of the first convex region and the length of the second convex region are longer than the length of the mounting region.

[0083] (4) In any one of the wiring substrates (1) to (3) above, the first convex region, the mounting region, and the second convex region are aligned in a first direction, and the width of the first convex region in the first direction and the width of the second convex region in the first direction are 0.8 to 1.2 times the width of the mounting region in the first direction.

[0084] (5) In the wiring board according to any one of (1) to (4) above, the amount of protrusion of the mounting region is smaller than the amount of protrusion of the first convex region and the amount of protrusion of the second convex region.

[0085] (6) In the wiring board according to any one of (1) to (5) above, the first convex region and the second convex region are spaced apart from the edge of the first plate surface.

[0086] (7) An electronic device includes: a wiring board according to any one of (1) to (6) above; and an electronic component mounted on the wiring board.

[0087] The present disclosure can be used in wiring boards and electronic devices.

[0088] 1, 1A to 1J Wiring board 10 Insulating base 11 First plate surface 11a to 11d First side to fourth side (edge ​​of first plate surface) 12 Second plate surface 20 Wiring conductor 21 Pad portion 22 Film conductor 23 Via conductor 111, 111A, 111Aa, 111Ab Mounting area 112 First convex area 113 Second convex area 114 Third convex area 115 Fourth convex area 116 First concave area 117 Second concave area 119 Edge 120 Electronic component 130 Shielding case 200 Electronic module 210 Module substrate Ex1 to Ex3 Areas Ey1 to Ey3 Areas E1 to E4 Four corner areas E11, E12 Edges h1 to h3 Height dimension h11 to h13 Height X1, Y1 Distance X21 to X23 Width Y11 to Y13 Vertical

Claims

1. A wiring board comprising a flat insulating substrate having a first board surface, and wiring conductors located inside and on the surface of the insulating substrate, wherein the first board surface has a mounting area for electronic components, and a first convex region and a second convex region having bulges located on one side and the other side sandwiching the mounting area.

2. The distance between the mounting area and the edge of the first board surface in a first direction along the first board surface is longer than the distance between the mounting area and the edge of the first board surface in a second direction orthogonal to the first direction and along the first board surface, and the first convex region, the mounting area, and the second convex region are arranged in the first direction. The wiring board according to claim 1.

3. The first convex region, the mounting area, and the second convex region are arranged in a first direction, and in a second direction orthogonal to the first direction and along the first board surface, the lengths of the first convex region and the second convex region are longer than the length of the mounting area. The wiring board according to claim 1 or claim 2.

4. The first convex region, the mounting area, and the second convex region are arranged in a first direction, and the widths of the first convex region and the second convex region in the first direction are 0.8 times to 1.2 times the width of the mounting area in the first direction. The wiring board according to any one of claims 1 to 3.

5. The amount of bulge of the mounting area is smaller than the amount of bulge of the first convex region and the amount of bulge of the second convex region. The wiring board according to any one of claims 1 to 4.

6. The first convex region and the second convex region are away from the edge of the first board surface. The wiring board according to any one of claims 1 to 5.

7. An electronic device comprising the wiring board according to any one of claims 1 to 6, and electronic components mounted on the wiring board.

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