Wiring board and semiconductor device

Abstract

This wiring board comprises a substrate body having: a first base material containing ceramic as a material; and a second base material laminated on the first base material and containing an organic material as a material. In a first direction view in which the substrate body is viewed from a lamination direction of the first base material and the second base material, the substrate body has a straight section extending linearly, and a first recessed section recessed inward from the straight section. The first recessed section has a first step portion at the boundary between the first base material and the second base material in a cross-section of a second direction view in which the substrate body is viewed from a direction crossing the lamination direction.

Description

Wiring board and semiconductor device

[0001] The present disclosure relates to a wiring substrate and a semiconductor device.

[0002] 2. Description of the Related Art Conventionally, wiring boards have been known that have a substrate body in which a plurality of base materials made of different materials are bonded together (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2007-96246

[0004] The wiring board of the present disclosure comprises a substrate body having a first substrate containing ceramic as a material and a second substrate laminated on the first substrate and containing an organic material as a material, wherein when viewed in a first direction in which the substrate body is viewed from the stacking direction of the first substrate and the second substrate, the substrate body has a straight portion extending linearly and a first recess that is recessed inward from the straight portion, and the first recess has a first step portion at the boundary between the first substrate and the second substrate in a cross section viewed in a second direction in which the substrate body is viewed from a direction intersecting the stacking direction.

[0005] FIG. 1 is a perspective view showing an example of the configuration of a wiring board according to an embodiment. FIG. 2 is an explanatory diagram of a substrate main body in the wiring board according to an embodiment. FIG. 3 is an explanatory diagram of a straight portion in the wiring board according to an embodiment. FIG. 4 is an explanatory diagram of a first recess in the wiring board according to an embodiment. FIG. 5 is an explanatory diagram of a second recess in the wiring board according to an embodiment. FIG. 6 is a diagram showing an example of a cross section taken along line A-A in FIG. 2. FIG. 7 is a diagram showing an example of a cross section taken along line A-A in FIG. 2. FIG. 8 is a diagram showing an example of a cross section taken along line B-B in FIG. 2. FIG. 9 is a diagram showing an example of a cross section taken along line B-B in FIG. 2. FIG. 10 is an explanatory diagram of wiring in a wiring board according to an embodiment. FIG. 11 is a cross-sectional view showing an example of the configuration of a semiconductor device according to an embodiment.

[0006] Hereinafter, embodiments for carrying out a wiring board and a semiconductor device according to the present disclosure (hereinafter referred to as "embodiments") will be described in detail with reference to the drawings. Note that the present disclosure is not limited to these embodiments. Furthermore, the embodiments can be appropriately combined as long as the processing content is not contradictory. Furthermore, the same components in the following embodiments will be assigned the same reference numerals, and redundant explanations will be omitted.

[0007] In addition, in the drawings referred to below, to make the explanation easier to understand, an orthogonal coordinate system may be shown in which the X-axis direction, Y-axis direction, and Z-axis direction, which are perpendicular to each other, are defined, and the Z-axis direction is the thickness direction of the wiring board.

[0008] <Wiring Board> Fig. 1 is a perspective view showing an example of the configuration of a wiring board according to an embodiment. Fig. 2 is an explanatory diagram of a substrate body in the wiring board according to an embodiment. Fig. 3 is an explanatory diagram of a straight portion in the wiring board according to an embodiment. Fig. 4 is an explanatory diagram of a first recess in the wiring board according to an embodiment. Fig. 5 is an explanatory diagram of a second recess in the wiring board according to an embodiment. Note that Figs. 2, 3, and 5 each show an example of a substrate body 101 as viewed in a first direction D1, which will be described later. Fig. 4 also shows a perspective view of an example of the substrate body 101.

[0009] As shown in FIG. 1, the wiring substrate 100 according to the embodiment comprises a substrate body 101, a first wiring 30 (see FIG. 10), a second wiring 40 (see FIG. 10), and a connecting conductor 50 (see FIG. 10).

[0010] The substrate body 101 includes a first substrate 10 and a second substrate 20. The substrate body 101 is a laminate of the first substrate 10 and the second substrate 20. The first substrate 10 includes an inorganic material as a material. The inorganic material may be ceramic. The second substrate 20 includes an organic material as a material. The organic material may be an organic resin. The detailed configurations of the first substrate 10 and the second substrate 20 will be described later.

[0011] The substrate body 101 may be rectangular when viewed in a first direction D1 when the substrate body 101 is viewed from the stacking direction (Z-axis direction) of the first substrate 10 and the second substrate 20 (for example, a planar view when the substrate body 101 is viewed from the positive direction of the Z-axis, and a bottom view when the substrate body 101 is viewed from the negative direction of the Z-axis).

[0012] 1 and 2, the substrate body 101 includes a straight portion 102, a first recess 103, and a first step portion 104. The straight portion 102 is located on the outer edge of the substrate body 101. The straight portion 102 extends linearly when viewed in the first direction D1.

[0013] The straight portion 102 does not necessarily have to be a perfect straight line. The straight portion 102 may have, for example, a bulge or a depression in the extension direction of the straight portion 102. The straight portion 102 may also have, for example, localized unevenness. Such a bulge, depression, or unevenness is a minor change in the straight portion 102 compared to the first recess 103 described below.

[0014] As described above, the substrate body 101 may be rectangular when viewed in the first direction D1. In this case, as illustrated in Fig. 3, the "rectangular shape" means that two sets of parallel straight portions 102 (two sides) intersecting at right angles constitute at least a part of the outer edge of the substrate body 101. Furthermore, for example, the straight portions 102 may occupy less than half of the outer edge of the substrate body 101.

[0015] 1 and 2 , the first recess 103 is a portion recessed inward from the straight portion 102 when viewed in the first direction D1. The first recess 103 may be located at a corner of the substrate body 101 when viewed in the first direction D1. The first recess 103 may be located at one of the four corners of the substrate body 101 when viewed in the first direction D1. This eliminates edges at the corners of the substrate body 101, thereby reducing the risk of interference with the surrounding area of ​​the substrate body 101.

[0016] The first recess 103 may have a shape that curves inward when viewed in the first direction D1. Alternatively, the first recess 103 may have no bottom, i.e., the first recess 103 may be formed by cutting out the substrate body 101 in the first direction D1.

[0017] The first recess 103 may be formed into a castellation by being plated with copper or the like. Another member (not shown) made of metal such as copper may be bonded to the first recess 103 by being adhered or fitted with an adhesive or the like.

[0018] 4, the first recess 103 may have a bottom (a bottomed recess). In this case, the first recess 103 may have a bottom formed by the first base material 10 made of an inorganic material, and the second base material 20 made of an organic material may be curved inward when viewed in the first direction D1.

[0019] 1 and 4 , the first step portion 104 is located on the inner surface of the first recess 103, which is the outer surface of the substrate body 101, and is also located at the boundary between the first base material 10 and the second base material 20 when viewed in a second direction D2 intersecting the first direction D1 and viewing the substrate body 101 in that direction (i.e., when viewed from the side of the substrate body 101). The second direction D2 may be perpendicular to the first direction D1.

[0020] When assembling a semiconductor device 300 (see FIG. 11 ) using the wiring substrate 100, another member is bonded to the first recess 103 using an adhesive or the like, or another member is fitted and joined. In such cases, the first step 104 generates friction between the first recess 103 and the adhesive or between the first recess 103 and the member. This improves the holding force of the first recess 103 to hold the adhesive or member, reducing the risk of the adhesive peeling off or the member falling off from the first recess 103. As a result, the bonding reliability of the member to the substrate body 101 can be improved.

[0021] As shown in FIGS. 1 and 2 , the substrate body 101 may have a second recess 106 located in a central portion 105 as viewed in the first direction D1. The second recess 106 may be rectangular as viewed in the first direction D1. The second recess 106 may be located across the second substrate 20 and the first substrate 10 and penetrate at least one of the first substrate 10 and the second substrate 20. The second recess 106 may have a bottom (a bottomed recess) or may be bottomless, i.e., a through-hole that penetrates the substrate body 101, i.e., the first substrate 10 and the second substrate 20, in the first direction D1. FIG. 1 illustrates the second recess 106 as a through-hole. Note that the substrate body 101 may not have the second recess 106.

[0022] Ceramics have higher rigidity than organic materials. Therefore, the substrate body 101 composed of the first substrate 10 containing ceramic as a material and the second substrate 20 containing organic material as a material can have improved rigidity compared to a substrate composed only of organic materials. As a result, even if the substrate body 101 is made thin, it is easy to ensure rigidity without adding reinforcing members or the like.

[0023] Furthermore, when the substrate body 101 includes the second recess 106, it can be made smaller (thinner) than when the second recess 106 is provided only in the second base material 20, i.e., only in the organic material. Furthermore, the substrate body 101 can be made lighter because the volumes of the first base material 10 and the second base material 20 can be reduced by the amount of the second recess 106.

[0024] Furthermore, when the substrate body 101 includes the second recess 106, a third side surface 14 (described later) that serves as the inner surface of the first substrate 10 and a fourth side surface 24 (described later) that serves as the inner surface of the second substrate 20 that constitute the inner surface 107 of the second recess 106 may both be aligned parallel to the first direction D1. This makes it easier to control the direction of reflection when light emitted from the semiconductor element 310 is reflected by the third side surface 14 or the fourth side surface 24, for example, when the semiconductor element 310 (see FIG. 11 ) mounted on the wiring substrate 100 is a light-emitting element.

[0025] Furthermore, the substrate body 101 may be configured such that the third side surface 14 of the first base material 10 and the fourth side surface 24 of the second base material 20 are flush with each other. Because the third side surface 14 and the fourth side surface 24 form an integrated plane, for example, when the semiconductor element 310 mounted on the wiring substrate 100 is a light-emitting element, it becomes easier to control the direction of reflection of light emitted from the semiconductor element 310.

[0026] 5, the central portion 105 of the substrate body 101 may be a region excluding the outer edge of the substrate body 101. Therefore, the second recess 106 may be positioned offset from the center toward the outer edge of the substrate body 101 when viewed in the first direction D1 (see FIG. 1). Furthermore, multiple second recesses 106 may be positioned in the central portion 105.

[0027] Figures 6 and 7 are diagrams showing an example of a cross section taken along line A-A in Figure 2. Figures 8 and 9 are diagrams showing an example of a cross section taken along line B-B in Figure 2. That is, Figures 6 and 7 show a cross section of the first recess 103. Figure 8 shows a cross section of one end of the straight portion 102. Figure 9 shows a cross section of the other end of the straight portion 102.

[0028] 6 and other figures, the first substrate 10 is made of ceramic. Examples of the ceramic that can be used include ceramics made of at least one material selected from the group consisting of aluminum oxide, silicon oxide, zirconium oxide, silicon carbide, silicon nitride, and aluminum nitride, or ceramics made of composite oxides such as mullite, zircon, steatite, enstatite, glass ceramics, and glass. The first substrate 10 contains a glass component in addition to the ceramic.

[0029] The first substrate 10 has a first surface 11 and a second surface 12 located opposite the first surface 11. The first substrate 10 may be a plate-like body having the first surface 11 and the second surface 12 as its main surfaces. The first substrate 10 also has a first side surface 13 connecting the first surface 11 and the second surface 12 at one end portion on the outer edge side. The first side surface 13 forms the outer surface of the first substrate 10. As shown in FIG. 9 , the first substrate 10 also has a third side surface 14 connecting the first surface 11 and the second surface 12 at the other end portion on the inner edge side. The third side surface 14 forms the inner surface of the first substrate 10.

[0030] The first substrate 10 may also have a plurality of ceramic layers 15. In this case, the plurality of ceramic layers 15 may be stacked along the thickness direction (Z-axis direction) of the first substrate 10. By configuring the first substrate 10 using a plurality of ceramic layers 15 in this manner, it is possible to obtain a first substrate 10 having a wiring layer 32 (described later) therein.

[0031] The wiring board 100 having such a first base material 10 has a high degree of freedom in design. Furthermore, by configuring the first base material 10 using a plurality of ceramic layers 15, it is possible to manufacture the first base material 10 while checking for each layer whether the first wiring 30 described below is properly formed. This allows the yield of the first base material 10 to be improved.

[0032] In the example shown in Figure 6, the first substrate 10 has three ceramic layers 15, but the number of ceramic layers 15 is not limited to three. The number of ceramic layers 15 may be two, or may be four or more. Furthermore, the first substrate 10 does not necessarily have to have a multilayer structure. In other words, the first substrate 10 may be a single layer.

[0033] As described above, the second base material 20 includes an organic material. The organic material may be an organic resin. The organic resin may be, for example, an epoxy resin, an acrylic resin, a polycarbonate resin, a polyimide resin, an olefin resin, or a polyphenylene resin. The second base material 20 may also include multiple types of organic resins.

[0034] The organic resin may be, for example, polytetrafluoroethylene (PTFE) or other fluororesins or polyphenylene ether resins. The second substrate 20 may contain components other than the organic resin. Examples of components other than the organic resin contained in the second substrate 20 include inorganic materials such as silica and rubber materials. The content of the inorganic material such as silica in the second substrate 20, in terms of mass %, may be lower than the content of the organic resin in the second substrate 20. More specifically, the content of the inorganic material such as silica in the second substrate 20 may be 50 mass % or more of the second substrate 20, and the content of the organic resin in the second substrate 20 may be 50 mass % or less of the second substrate 20.

[0035] The second substrate 20 has a third surface 21 and a fourth surface 22 located opposite the third surface 21. The second substrate 20 may be a plate-like body having the third surface 21 and the fourth surface 22 as its main surfaces. The second substrate 20 also has a second side surface 23 connecting the third surface 21 and the fourth surface 22 at one end portion on the outer edge side. The second side surface 23 forms the outer surface of the second substrate 20. As shown in FIG. 9 , the second substrate 20 also has a fourth side surface 24 connecting the third surface 21 and the fourth surface 22 at the other end portion on the inner edge side. The fourth side surface 24 forms the inner surface of the second substrate 20.

[0036] The second substrate 20 is overlaid on the first surface 11 of the first substrate 10. The third surface 21 of the second substrate 20 is bonded to the first surface 11 of the first substrate 10. In other words, the second substrate 20 is directly bonded to the first substrate 10 without an adhesive layer therebetween.

[0037] Specifically, the ceramic layer 15 of the first substrate 10 may contain, as a material, a ceramic containing hydroxyl groups on the surface. In this case, the second substrate 20 may be chemically bonded to the first substrate 10 via the hydroxyl groups. This allows the first substrate 10 and the second substrate 20 to be hydrogen bonded to each other via the hydroxyl groups.

[0038] As described above, since there is no adhesive layer for bonding the first substrate 10 and the second substrate 20, the thickness of the wiring substrate 100 is reduced, enabling miniaturization. Furthermore, substrates made of organic materials are lighter than substrates made of ceramic. Therefore, the wiring substrate 100 according to the present disclosure, which includes the first substrate 10 made of ceramic and the second substrate 20 made of organic materials, can be made lighter than a wiring substrate made only of substrates made of ceramic.

[0039] The second base material 20 may have a plurality of organic resin layers 25. The plurality of organic resin layers 25 may be stacked along the thickness direction (Z-axis direction) of the second base material 20. By configuring the second base material 20 using a plurality of organic resin layers 25, it is possible to obtain a second base material 20 having a wiring layer 42 (described later) therein. A wiring board 100 having such a second base material 20 has a high degree of freedom in design.

[0040] 6 and the like, the second base material 20 has three organic resin layers 25, but the number of organic resin layers 25 is not limited to three. The number of organic resin layers 25 may be two, or may be four or more.

[0041] The second substrate 20 containing an organic material is easier to form a fine wiring pattern on than a substrate containing an inorganic material. On the other hand, the first substrate 10 containing a ceramic material has higher rigidity than the second substrate 20. Furthermore, the first substrate 10 containing a ceramic material has a lower density than the second substrate 20.

[0042] The wiring board 100 can increase rigidity while achieving finer wiring and narrower pitches by combining the first substrate 10 and the second substrate 20. Since warping of the board becomes more pronounced as the board becomes larger, the configuration of the wiring board 100 in which the first substrate 10 compensates for the low rigidity of the second substrate 20 is particularly useful for increasing the size of the board.

[0043] 6, at one end portion on the outer edge side of the substrate body 101, the first step portion 104 may be such that the second base material 20 protrudes outward beyond the first base material 10 in a cross section viewed in the second direction D2 (see FIG. 1). In this way, in the example shown in FIG. 6, the second base material 20 made of an organic material protrudes beyond the first base material 10, thereby reducing damage to components mounted on the substrate body 101.

[0044] 7, at one end portion on the outer edge side of the substrate body 101, the first step portion 104 may be such that the first base material 10 protrudes outward beyond the second base material 20 in a cross section viewed in the second direction D2. In this way, in the example shown in Fig. 7, the first base material 10 made of ceramic protrudes beyond the second base material 20, thereby increasing the rigidity of the substrate body 101.

[0045] 6 and 7 , in a cross section viewed in the second direction D2, the first recess 103 may have a corner 26 that is convexly curved from the fourth surface 22 to the second side surface 23 of the second base material 20. Furthermore, in a cross section viewed in the second direction D2, the first recess 103 may have a corner 16 that is convexly curved from the first surface 11 to the first side surface 13 of the first base material 10.

[0046] 8 , at one end portion on the outer edge side of the substrate body 101, the straight portion 102 may have a corner 16 bent within a predetermined angle range including a right angle from the first surface 11 to the first side surface 13 of the first base material 10 in a cross section viewed in the second direction D2. For example, the straight portion 102 may have a corner 26 bent within a range of 80° to 100° from the first surface 11 to the first side surface 13 of the first base material 10 in a cross section viewed in the second direction D2.

[0047] Furthermore, the straight portion 102 may have a corner 26 that is bent within a predetermined angle range including a right angle from the fourth surface 22 to the second side surface 23 of the second base material 20. For example, the straight portion 102 may have a corner 26 that is bent within a range of 80° to 100° from the fourth surface 22 to the second side surface 23 of the second base material 20 in a cross section viewed in the second direction D2.

[0048] Furthermore, the straight portion 102 may be a continuous surface without a step between the first side surface 13 and the second side surface 23. That is, in the straight portion 102, there is no clear step between the first surface 11, the fourth surface 22, the first side surface 13, and the second side surface 23.

[0049] When another component is bonded to the straight portion 102 using an adhesive or the like or when another component is fitted and joined, voids are unlikely to form between the straight portion 102 and the adhesive or between the straight portion 102 and the component. This is because the corners of the straight portion 102 are bent within a predetermined angle range, including right angles, and the first side surface 13 and the second side surface 23 are continuous surfaces without any steps. This improves the holding force for the component and reduces the risk of the adhesive peeling off from the straight portion 102 or the component falling off. As a result, the joining reliability of the component to the substrate body 101 can be improved.

[0050] Moreover, in a cross section viewed in the second direction D2, the straight portion 102 extends continuously between the first substrate 10 and the second substrate 20. By configuring the straight portion 102 without any steps in this way, the risk of interference with the surrounding area of ​​the substrate main body 101 can be reduced.

[0051] Furthermore, the surface roughness of at least a portion of the first side surface 13 of the first substrate 10 may be greater than the surface roughness of the fourth surface 22 of the second substrate 20. In this manner, the surface roughness of at least a portion of the first side surface 13, which is the outer surface of the first substrate 10, is greater than the fourth surface 22, which is the main surface of the second substrate 20. In other words, the surface roughness of the fourth surface 22 of the second substrate 20 is smaller. This facilitates suction, which is advantageous in manufacturing, for example, when a manufacturing process includes a step of suctioning the wiring substrate 100 using an automated machine. Furthermore, when bonding or fitting other components to the first side surface 13 using an adhesive or the like, the high surface roughness of the first side surface 13 generates friction between the first side surface 13 and the adhesive or between the first side surface 13 and the component. This improves the holding force of the adhesive or component held by the first side surface 13, reducing the risk of the adhesive peeling or component falling off from the first side surface 13. As a result, the reliability of bonding the component to the substrate body 101 can be improved.

[0052] 9 , at the other end portion on the inner edge side of the substrate body 101, the second step portion 108 is located on the inner surface of the second recess 106. The second step portion 108 is located at the boundary portion between the first substrate 10 and the second substrate 20 in the cross section viewed in the second direction D2.

[0053] When another component is bonded or fitted to the inner surface 107 of the second recess 106 using an adhesive or the like, the second step 108 generates friction between the second recess 106 and the adhesive or between the second recess 106 and the component. This improves the holding force of the second recess 106 to hold the adhesive or component, reducing the risk of the adhesive peeling or component falling off from the second recess 106. As a result, the reliability of the component bonding to the substrate body 101 can be improved. Furthermore, when an optical element such as a light receiving element or light emitting element, which is a semiconductor element 310 (see FIG. 11 ), is mounted in the second recess 106, the second step 108 can reduce unwanted light reflection or block unwanted light on the inner surface 107 of the second recess 106. This reduces unwanted light input and output to the optical element.

[0054] Even when the second recess 106 is a through hole, when another component is bonded or fitted to the inner surface of the second recess 106 using an adhesive or the like, the second step 108 (see FIG. 9 ) generates friction between the second recess 106 and the adhesive or between the second recess 106 and the component. This improves the holding force of the second recess 106 of the through hole to hold the adhesive or component, reducing the risk of the adhesive peeling or component falling off from the second recess 106. As a result, the reliability of the component bonding to the substrate body 101 can be improved. Furthermore, when an optical element such as a light receiving element or light emitting element, which is a semiconductor element 310 (see FIG. 11 ), is mounted in the second recess 106 of the through hole, the second step 108 can reduce unwanted light reflection or block unwanted light on the inner surface 107 of the second recess 106. This reduces unwanted light input and output to the optical element.

[0055] The second base material 20 may also contain a black organic material. In this case, carbon or the like may be added as a pigment to the organic material. This has the advantage of reducing light reflection when an image sensor is mounted as the semiconductor element 310 (see FIG. 11 ) and hiding discoloration of the second base material 20 over time.

[0056] <First Wiring and Second Wiring> Fig. 10 is an explanatory diagram of wiring in a wiring board according to an embodiment. As shown in Fig. 10, the first wiring 30 is located inside the first base material 10 and extends from one of the first surface 11 and the second surface 12 to the other. Note that "extending" here does not necessarily mean extending the shortest distance. For example, the first wiring 30 may have a portion (wiring layer 32) extending along the first surface 11.

[0057] The first wiring 30 may have a plurality of vias 31 and one or more wiring layers 32. The vias 31 penetrate one or more ceramic layers 15. The wiring layers 32 are located between adjacent ceramic layers 15 and electrically connect the plurality of vias 31 to each other.

[0058] As described above, the wiring substrate 100 has the first wiring 30 on the first base material 10, which allows greater freedom in wiring design compared to conventional wiring substrates that have wiring only on organic resin substrates. On the other hand, when wiring (first wiring 30 and second wiring 40) is provided on both the first base material 10 and the second base material 20, it is desirable to strengthen the bond between the first base material 10 and the second base material 20 so as to prevent misalignment between the first wiring 30 and the second wiring 40. Note that while the example shown in FIG. 10 illustrates a case in which the first wiring 30 has a wiring layer 32, the first wiring 30 does not necessarily have to have a wiring layer 32.

[0059] The second wiring 40 is located inside the second base material 20 and extends from one of the third surface 21 and the fourth surface 22 to the other. Note that "extending" here does not necessarily mean extending the shortest distance. The second wiring 40 may be electrically connected to the first wiring 30 at the interface, which is the bonding surface between the first base material 10 and the second base material 20.

[0060] The second wiring 40 may have a plurality of vias 41. The vias 41 penetrate one or more organic resin layers 25. The second wiring 40 may have a wiring layer located between adjacent organic resin layers 25 and electrically connecting the plurality of vias 41. The second wiring 40 may also have a wiring layer (land) located on the fourth surface 22 of the second substrate 20.

[0061] The first wiring 30 and the second wiring 40 may be, for example, metal conductors made of copper or silver. For example, both the first wiring 30 and the second wiring 40 may be metal conductors made of copper. Also, both the first wiring 30 and the second wiring 40 may be metal conductors made of silver. Also, one of the first wiring 30 and the second wiring 40 may be a metal conductor made of copper, and the other may be a metal conductor made of silver.

[0062] By making all of the first wiring 30 and the second wiring 40 metal conductors made of copper or silver, it is possible to obtain higher electrical characteristics than when, for example, one of the first wiring 30 and the second wiring 40 is made of a metal conductor other than copper or silver.

[0063] Of the first wiring 30 and the second wiring 40, only the first wiring 30 may contain a glass component. In this case, the first wiring 30 is firmly bonded to the first substrate 10, which also contains a glass component, via the glass component. Specifically, the glass component contained in the first wiring 30 is integrated with the glass component contained in the first substrate by firing. This integrated glass component hardens while entering the gaps between the multiple metal particles that make up the first wiring 30, thereby generating an anchor effect. The first wiring 30 is firmly bonded to the first substrate 10 due to this anchor effect. This can increase the rigidity of the first substrate 10.

[0064] Furthermore, when the first wiring 30 contains a glass component, the shrinkage rates of the first base material 10 and the first wiring 30 can be made uniform to some extent in the firing step during the manufacture of the wiring substrate 100. This makes it possible to make the positional deviation of the first wiring 30 less likely to occur.

[0065] The first wiring 30 may be formed, for example, by printing a conductive paste containing copper and glass components on a green sheet, which is the raw material for the ceramic layer 15, and firing the green sheet simultaneously. Specifically, the conductive paste may contain, for example, copper powder, borosilicate glass powder, and silica particles. The first wiring 30 may be a metal conductor made of, for example, tungsten or molybdenum. As an example, the via 31 may be a metal conductor made of tungsten, and the wiring layer 32 may be a metal conductor made of molybdenum. Alternatively, the via 31 may be a metal conductor made of molybdenum, and the wiring layer 32 may be a metal conductor made of tungsten. Alternatively, both the via 31 and the wiring layer 32 may be metal conductors made of tungsten, or both the via 31 and the wiring layer 32 may be metal conductors made of molybdenum. The first wiring 30 may be a metal conductor made of, for example, copper or gold as a main component, and containing tungsten or molybdenum.

[0066] On the other hand, the second wiring 40 may be formed by copper plating, which allows the first wiring 30 and the second wiring 40 to have a configuration in which only the first wiring 30 contains a glass component.

[0067] 10 , the connection conductor 50 may be a conductor containing a glass component. The connection conductor 50 is located between the first substrate 10 and the second substrate 20, and electrically connects the first wiring 30 and the second wiring 40. A wiring board 100 having such a connection conductor 50 has a high degree of freedom in design.

[0068] The connection conductor 50 may be a conductor containing a glass component. The connection conductor 50 is located between the first substrate 10 and the second substrate 20, and electrically connects the first wiring 30 and the second wiring 40. The wiring board 100 having such a connection conductor 50 has a high degree of freedom in design.

[0069] The connecting conductor 50 may have a shape that is wider in the direction along the first surface 11 than the via 41 of the second wiring 40 that is in direct contact with the connecting conductor 50. This makes it easier to align the connecting conductor 50 with the via 41 of the second wiring 40, thereby improving the yield of the wiring substrate 100.

[0070] The connection conductor 50 may be bonded to the first surface 11 of the first substrate 10 by a glass component. This glass component is contained in the connection conductor 50 and the first substrate 10. In this way, the connection conductor 50 is firmly bonded to the first substrate 10, which also contains a glass component, via the glass component.

[0071] Furthermore, for example, the second substrate 20 may be bonded to the connecting conductor 50 and the first surface 11 of the first substrate 10 by an anchor effect. The anchor effect may be caused by, for example, a glass component contained in the first substrate 10 and the connecting conductor 50.

[0072] In this way, the second substrate 20 is joined to the connecting conductor 50 and the first surface 11 of the first substrate 10 by the anchor effect, which makes it difficult for the first substrate 10 and the connecting conductor 50 to shift relative to the second substrate 20 in the direction along the first surface 11. This stabilizes the physical connection between the first wiring 30 and the second wiring 40.

[0073] Furthermore, for example, if only the first wiring 30 of the first wiring 30 and the second wiring 40 contains a glass component, the first wiring 30 is firmly bonded to the connection conductor 50, which also contains a glass component, via the glass component, thereby stabilizing the physical connection between the first wiring 30 and the connection conductor 50.

[0074] <Semiconductor Device> Fig. 11 is a cross-sectional view showing an example of the configuration of a semiconductor device according to an embodiment. As shown in Fig. 11, a semiconductor device 300 includes a wiring substrate 100 and a semiconductor element 310. The semiconductor element 310 is mounted on the wiring substrate 100. In the example shown in Fig. 11, the semiconductor element 310 is mounted on the second surface 12 of the first base material 10 in the wiring substrate 100. The semiconductor element 310 is positioned so as to face the opening edge of the first recess 103, which is a through-hole.

[0075] When assembling the semiconductor device 300 using the wiring substrate 100, another member is bonded to the first recess 103 using an adhesive or the like, or another member is fitted and joined. In this case, the first step 104 generates friction between the first recess 103 and the adhesive or between the first recess 103 and the member. This improves the holding force of the first recess 103 to hold the adhesive or member, and reduces the risk of the adhesive peeling off or the member falling off from the first recess 103. As a result, the bonding reliability of the member to the substrate body 101 can be improved.

[0076] The present disclosure has been described in detail above, but the present disclosure is not limited to the above-described embodiments, and various modifications, improvements, etc. are possible within the scope that does not deviate from the gist of the present disclosure.

[0077] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0078] The present technology can also be configured as follows. (1) A wiring board including a substrate body having a first base material containing ceramic and a second base material stacked on the first base material and containing an organic material, wherein, when viewed in a first direction in which the substrate body is viewed from a stacking direction of the first base material and the second base material, the substrate body has a straight portion extending linearly and a first recessed portion recessed inward from the straight portion, and the first recessed portion has a first step portion at a boundary portion between the first base material and the second base material in a cross section viewed in a second direction in which the substrate body is viewed from a direction intersecting the stacking direction. (2) The wiring board according to (1), wherein the straight portion extends continuously between the first base material and the second base material in the cross section viewed in the second direction. (3) The wiring board according to (1) or (2), wherein the substrate body is rectangular when viewed in the first direction, and the first recessed portion is located at a corner of the rectangular substrate body. (4) The wiring board according to any one of (1) to (3), further comprising: a second recess located in a central portion of the board body when viewed in the first direction, positioned across the second substrate and the first substrate, and penetrating at least one of the first substrate and the second substrate, wherein an inner surface of the second recess has a second step portion at a boundary between the first substrate and the second substrate in a cross section when viewed in the second direction. (5) The wiring board according to (4), wherein the second recess is a through hole penetrating the second substrate and the first substrate. (6) The wiring board according to any one of (1) to (5), wherein the first substrate and the second substrate are directly bonded.(7) The wiring board according to any one of (1) to (6), wherein the first substrate has a first surface, a second surface opposite the first surface, and a first side surface connecting the first surface and the second surface; the second substrate has a third surface joining the first surface, a fourth surface opposite the third surface, and a second side surface connecting the third surface and the fourth surface; the first recess has a convexly curved corner from the fourth surface to the second side surface in a cross section viewed in the second direction; and the straight portion has a corner bent within a predetermined angle range including a right angle from the fourth surface to the second side surface in a cross section viewed in the second direction, and the second side surface is a continuous surface without any steps. (8) The wiring board according to any one of (1) to (7), wherein the first substrate has a first surface, a second surface opposite the first surface, and a first side surface connecting the first surface and the second surface, the second substrate has a third surface bonded to the first surface, a fourth surface opposite the third surface, and a second side surface connecting the third surface and the fourth surface, and the surface roughness of at least a portion of the first side surface is greater than the surface roughness of the fourth surface. (9) The wiring board according to any one of (1) to (8), wherein the first step portion is such that the first substrate protrudes beyond the second substrate. (10) The wiring board according to any one of (1) to (8), wherein the first step portion is such that the second substrate protrudes beyond the first substrate. (11) A semiconductor device comprising: the wiring board according to any one of (1) to (10); and a semiconductor element mounted on the wiring board.

[0079] REFERENCE SIGNS LIST 10 First substrate 11 First surface 12 Second surface 13 First side surface 16 Corner portion 20 Second substrate 21 Third surface 22 Fourth surface 23 Second side surface 26 Corner portion 100 Wiring substrate 101 Substrate body 102 Straight portion 103 First recess 104 First step portion 105 Central portion 106 Second recess 107 Inner surface 108 Second step portion 300 Semiconductor device 310 Semiconductor element D1 First direction D2 Second direction

Claims

1. A wiring board comprising: a substrate body having a first base material containing ceramic as a material, and a second base material laminated on the first base material and containing an organic material as a material; when viewed in a first direction when the substrate body is viewed from the stacking direction of the first base material and the second base material, the substrate body has a straight portion extending linearly and a first recessed portion recessed inward from the straight portion, and the first recessed portion has a first step portion at the boundary between the first substrate and the second substrate in a cross section viewed in a second direction when the substrate body is viewed from a direction intersecting the stacking direction.

2. The wiring board according to claim 1, wherein the straight portion extends continuously between the first base material and the second base material in a cross section viewed in the second direction.

3. The wiring board according to claim 1, wherein the substrate body is rectangular when viewed in the first direction, and the first recess is located at a corner of the rectangular substrate body.

4. The wiring board as described in claim 1, further comprising a second recess located in the center of the board body when viewed in the first direction, positioned across the second substrate and the first substrate, and penetrating at least one of the first substrate and the second substrate, wherein the inner surface of the second recess has a second step portion at the boundary between the first substrate and the second substrate in a cross section viewed in the second direction.

5. The wiring board according to claim 4, wherein the second recess is a through hole penetrating the second base material and the first base material.

6. The wiring board according to claim 1, wherein the first base material and the second base material are directly bonded to each other.

7. The wiring board described in claim 1, wherein the first substrate has a first surface, a second surface opposite the first surface, and a first side surface connecting the first surface and the second surface, the second substrate has a third surface joining the first surface, a fourth surface opposite the third surface, and a second side surface connecting the third surface and the fourth surface, the first recess has a convexly curved corner from the fourth surface to the second side surface in a cross section viewed in the second direction, and the straight portion has a corner bent within a predetermined angle range including a right angle from the fourth surface to the second side surface in a cross section viewed in the second direction, and the second side surface is a continuous surface without a step.

8. The wiring board described in claim 1, wherein the first substrate has a first surface, a second surface opposite the first surface, and a first side surface connecting the first surface and the second surface, the second substrate has a third surface joining the first surface, a fourth surface opposite the third surface, and a second side surface connecting the third surface and the fourth surface, and the surface roughness of at least a portion of the first side surface is greater than the surface roughness of the fourth surface.

9. The wiring board according to claim 1, wherein the first step portion is such that the first base material protrudes further than the second base material.

10. The wiring board according to claim 1, wherein the first step portion is such that the second base material protrudes further than the first base material.

11. A semiconductor device comprising: a wiring board according to any one of claims 1 to 10; and a semiconductor element mounted on the wiring board.