Wiring board and semiconductor device

Abstract

This wiring board comprises a first base material and a second base material. The first base material includes a first surface and a second surface positioned opposite to the first surface, and contains an inorganic material as a material thereof. The second base material overlaps the first surface, is directly bonded to the first base material, and contains an organic material as a material thereof. The first surface includes a first central portion, and a first inclined portion positioned on an outer edge side of the first central portion and inclined toward the second surface toward the outer edge. The second base material extends from the first central portion to the first inclined portion along the first surface.

Description

Wiring board and semiconductor device

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

[0002] BACKGROUND ART Conventionally, in the field of wiring substrates used in semiconductor devices, a technique has been known in which a substrate made of ceramic, which is an inorganic material, and a substrate made of an organic material are combined by bonding (see, for example, Patent Document 1).

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

[0004] The wiring board of the present disclosure includes a first substrate and a second substrate. The first substrate has a first surface and a second surface located opposite the first surface, and contains an inorganic material as its material. The second substrate is overlaid on the first surface and directly bonded to the first substrate, and contains an organic material as its material. The first surface has a first central portion and a first inclined portion located on the outer edge side of the first central portion and inclined toward the second surface as it approaches the outer edge. The second substrate extends along the first surface from the first central portion to the first inclined portion.

[0005] FIG. 1 is a perspective view showing an example of the configuration of a wiring board according to an embodiment. FIG. 2 is a cross-sectional view of one end of a wiring board as viewed from the arrows A-A shown in FIG. 1. FIG. 3 is a plan view of a wiring board according to an embodiment. FIG. 4 is a bottom view of a wiring board according to an embodiment. FIG. 5 is an explanatory diagram (part 1) of the surface roughness of each surface of a first substrate and a second substrate in a wiring board according to an embodiment. FIG. 6 is an explanatory diagram (part 2) of the surface roughness of each surface of a first substrate and a second substrate in a wiring board according to an embodiment. FIG. 7 is a cross-sectional view showing an example of the configuration of a semiconductor device according to an embodiment. FIG. 8 is a cross-sectional view showing an example of the configuration of a wiring board according to another embodiment and a semiconductor device using a wiring board according to another embodiment.

[0006] However, in the above-mentioned conventional techniques, since different types of materials are bonded to each other, there is room for improvement in terms of improving the bonding reliability of the two substrates.

[0007] Therefore, a technology that can improve the reliability of the joint is desired.

[0008] 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.

[0009] 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.

[0010] <Embodiment> FIG. 1 is a perspective view showing an example of the configuration of a wiring board according to an embodiment. As shown in FIG. 1, the wiring board 100 according to the embodiment includes a first substrate 10, a second substrate 20, a first wiring 30 (see FIG. 2), a second wiring 40 (see FIG. 2), and a connecting conductor 50 (see FIG. 2). The wiring board 100 is a laminate of the first substrate 10 and the second substrate 20. The first substrate 10 contains an inorganic material as a material. The inorganic material may be ceramic. The second substrate 20 contains 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 using FIGS. 2 to 6.

[0011] The wiring substrate 100 may have a rectangular shape in a plan view, for example, when viewed from the second base material 20 side in the thickness direction (Z-axis direction) of the wiring substrate 100. The wiring substrate 100 may also have a recess 110 in the center in a plan view. The recess 110 may have a rectangular shape in a plan view. The recess 110 may have a shape with a bottom (a bottomed recess), or may have a shape without a bottom, i.e., a through-hole that penetrates through the wiring substrate 100 in the thickness direction. The wiring substrate 100 may also have a configuration without the recess 110.

[0012] Ceramics have higher rigidity than organic materials. Therefore, the wiring substrate 100 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 wiring substrate composed only of organic materials. This makes it easy to ensure the rigidity of the wiring substrate 100, even if the wiring substrate 100 is made thin, without adding reinforcing members or the like.

[0013] Furthermore, when the wiring substrate 100 includes the recess 110 formed between the first substrate 10 and the second substrate, the rigidity can be improved compared to when the recess 110 is formed only in the second substrate 20, i.e., only in an organic material, and therefore the wiring substrate 100 can be made smaller and thinner. Furthermore, the volume of the first substrate 10 and the second substrate 20 can be reduced by the amount of the recess 110, so the wiring substrate 100 can be made lighter.

[0014] Furthermore, when wiring substrate 100 includes recess 110, inner surface 101 of first substrate 10 and inner surface 201 of second substrate 20, which form inner surface 111 of recess 110, may both be aligned parallel to the thickness direction of wiring substrate 100. This makes it easier to control the direction of reflection when light emitted from semiconductor element 310 is reflected by inner surface 101 or inner surface 201, for example, when semiconductor element 310 (see FIG. 7 ) mounted on wiring substrate 100 is a light-emitting element.

[0015] Furthermore, in the wiring substrate 100, the inner surface 101 of the first base material 10 and the inner surface 201 of the second base material 20 may be flush with each other. This allows the inner surface 101 and the inner surface 201 to form an integrated flat surface, so that, 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.

[0016] FIG. 2 is a cross-sectional view of one end portion of the wiring board according to the embodiment, taken along the line A-A in FIG. 1 . FIG. 2 shows the outer edge side end portion of the wiring board according to the embodiment. FIG. 3 is a plan view of the wiring board according to the embodiment. FIG. 4 is a bottom view of the wiring board according to the embodiment. FIGS. 5 and 6 are explanatory diagrams of the surface roughness of each surface of the first substrate and the second substrate in the wiring board according to the embodiment. FIGS. 5 and 6 show the outer edge side end portion of the wiring board according to the embodiment. In addition, in FIGS. 3 and 4 , inclined portions (first inclined portion 16 and second inclined portion 18) described below are highlighted with dots.

[0017] <First Substrate> 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, and 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.

[0018] 2 , 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. The first side surface 13 forms the outer surface of the first substrate 10.

[0019] The first substrate 10 may also have a plurality of ceramic layers 14. In this case, the plurality of ceramic layers 14 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 14 in this manner, it is possible to obtain a first substrate 10 having a wiring layer 32 (described later) therein.

[0020] 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 14, it is possible to manufacture the first base material 10 while checking for each layer whether the first wiring 30, which will be described later, is properly formed. This allows the yield of the first base material 10 to be improved.

[0021] In the example shown in Fig. 2, the first substrate 10 has three ceramic layers 14, but the number of ceramic layers 14 is not limited to three. The number of ceramic layers 14 may be two, or 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.

[0022] In the first substrate 10, the first surface 11 has a first central portion 15 and a first inclined portion 16. The first central portion 15 is a region excluding the outer edge side of the first surface 11 in a plan view. The first central portion 15 is a flat surface. The first inclined portion 16 is located closer to the outer edge than the first central portion 15. The first inclined portion 16 is an inclined surface that inclines toward the second surface 12 as it approaches the outer edge of the first surface 11.

[0023] As shown in FIG. 3, when the first substrate 10 has a rectangular shape, the first inclined portions 16 may be located on each of the four sides 19 of the first substrate 10 in a plan view.

[0024] As shown in Fig. 2, in the first substrate 10, the second surface 12 has a second central portion 17 and a second inclined portion 18. The second central portion 17 is a region excluding the outer edge side of the second surface 12 in a plan view. The second central portion 17 is a flat surface. The second inclined portion 18 is located closer to the outer edge than the second central portion 17. The second inclined portion 18 is an inclined surface that inclines toward the first surface 11 as it approaches the outer edge of the second surface 12.

[0025] By having such a second inclined portion 18, the first substrate 10 does not have any sharp edges on the second surface 12, thereby reducing the possibility of damage due to collision with other parts, etc.

[0026] 4, when the first substrate 10 is rectangular, the second inclined portions 18 may be located on each of the four sides 19 of the first substrate 10 in a plan view. In this way, the second inclined portions 18 of the second surface 12 extend around the entire periphery of the first substrate 10, further reducing the possibility of breakage due to collision with other components, etc.

[0027] <Second Base Material> 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.

[0028] The organic resin may be, for example, polytetrafluoroethylene (PTFE) or other fluororesin or polyphenylene ether resin. 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.

[0029] 2 , 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. The second side surface 23 forms the outer surface of the second substrate 20.

[0030] 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.

[0031] In this way, since there is no adhesive layer for joining the first base material 10 and the second base material 20, the thickness of the wiring board 100 is reduced, and miniaturization is possible.

[0032] Specifically, the ceramic layer 14 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 via the hydroxyl groups.

[0033] The second base material 20 may have a plurality of organic resin layers 24. The plurality of organic resin layers 24 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 24, it is possible to obtain a second base material 20 having a wiring layer therein, which will be described later. A wiring board 100 having such a second base material 20 has a high degree of freedom in design.

[0034] 2, the second base material 20 has three organic resin layers 24, but the number of organic resin layers 24 is not limited to three. The number of organic resin layers 24 may be two, or may be four or more.

[0035] 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.

[0036] 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.

[0037] The second substrate 20 extends along the first surface 11 from the first central portion 15 to the first inclined portion 16 of the first surface 11 of the first substrate 10 .

[0038] In this way, the first inclined portion 16 extends from the first central portion 15 to the first inclined portion 16 along the first surface 11, and thus has a shape that covers the inclined surface of the first inclined portion 16. That is, the second substrate 20 has a shape that covers the first substrate 10 at the first inclined portion 16. The corners of the second substrate 20 are rounded according to the inclination of the first inclined portion 16. Therefore, force is less likely to be applied to the interface between the first substrate 10 and the second substrate 20. This makes it possible to protect the interface between the first substrate 10 and the second substrate 20.

[0039] Furthermore, since the first substrate 10 and the second substrate 20 are bonded to each other more at the outer edge of the wiring substrate 100, a larger bonding area can be secured between the first substrate 10 and the second substrate 20. This can improve bonding reliability.

[0040] Furthermore, when the first substrate 10 is rectangular, the first inclined portion 16 of the first surface 11 extends around the entire circumference of the first substrate 10, thereby further improving the bonding strength between the first substrate 10 and the second substrate 20.

[0041] The second base material 20 may also contain a black organic material. In this case, carbon or other pigments may be added to the organic material. This has the advantage of suppressing light reflection when an image sensor is mounted as the semiconductor element 310 (see FIG. 7 ) and hiding discoloration of the second base material 20 over time.

[0042] 5 , the surface roughness of the fourth surface 22 of the second substrate 20 may be smaller than the surface roughness of the first side surface 13 of the first substrate 10 and may also be smaller than the surface roughness of the second side surface 23. In this way, the small surface roughness of the fourth surface 22, which is the outer surface of the second substrate 20, is advantageous in manufacturing, for example, when the manufacturing process includes a step of sucking the wiring substrate 100 with an automatic machine, because it is easier to suck the wiring substrate 100.

[0043] Furthermore, the surface roughness of the fourth surface 22 of the second base material 20 may be smaller than the surface roughness of the first side surface 13 and the second side surface 23 of the first base material 10, as well as the surface roughness of the second inclined portion 18. This makes it easier to adsorb the wiring board 100 when the manufacturing process includes a step of adsorbing the wiring board 100 using an automatic machine, which is advantageous in manufacturing.

[0044] 6 , the surface roughness of the second surface 12 of the first substrate 10 may be smaller than the surface roughness of the first side surface 13 of the first substrate 10 and may also be smaller than the surface roughness of the second side surface 23 of the second substrate 20. This makes it easier to adsorb the wiring substrate 100 when the manufacturing process includes a step of adsorbing the wiring substrate 100 using an automatic machine, which is advantageous in manufacturing.

[0045] 2 , the first wiring 30 is located inside the first substrate 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) that extends along the first surface 11.

[0046] 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 14. The wiring layers 32 are located between adjacent ceramic layers 14 and electrically connect the plurality of vias 31 to each other.

[0047] In this way, the wiring board 100 has the first wiring 30 on the first base material 10, and therefore has a higher degree of freedom in wiring design compared to conventional wiring boards that have wiring only on an organic resin substrate. On the other hand, when a configuration is adopted in which 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 make the bond between the first base material 10 and the second base material 20 stronger so as to prevent misalignment between the first wiring 30 and the second wiring 40.

[0048] 2 shows an example in which the first wiring 30 has the wiring layer 32, but the first wiring 30 does not necessarily have to have the wiring layer 32. Furthermore, the first wiring 30 may have a wiring layer located on the surface (first surface 11 or second surface 12) of the first base material 10.

[0049] 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.

[0050] The second wiring 40 may have a plurality of vias 41. The vias 41 penetrate one or more organic resin layers 24. The second wiring 40 may have a wiring layer located between adjacent organic resin layers 24 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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 14, and then 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.

[0056] 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.

[0057] The first wiring 30 and the second wiring 40 are located in the first central portion 15 at least at the interface (bonding surface) between the first substrate 10 and the second substrate 20. For example, if the first wiring 30 and the second wiring 40 were located in the first inclined portion 16, the curvature of the outer edge of the second substrate 20 could cause problems such as separation between the first wiring 30 and the second wiring 40. However, by positioning the first wiring 30 and the second wiring 40 in the first inclined portion 16, it is possible to prevent problems such as separation between the first wiring 30 and the second wiring 40.

[0058] 2, 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] <Semiconductor Device> Fig. 7 is a cross-sectional view showing an example of the configuration of a semiconductor device according to an embodiment. As shown in Fig. 7, 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. 7, 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 recess 110, which is a through-hole.

[0066] In the semiconductor device 300, the second substrate 20 is shaped to cover the first substrate 10 at the first inclined portion 16 of the first substrate 10, and the corners of the second substrate 20 are rounded according to the inclination of the first inclined portion 16, so that force is less likely to be applied to the interface between the first substrate 10 and the second substrate 20. This makes it possible to protect the interface between the first substrate 10 and the second substrate 20.

[0067] Furthermore, in the semiconductor device 300, there is no adhesive layer for bonding the first substrate 10 and the second substrate 20, so the thickness of the wiring substrate 100 is reduced, enabling miniaturization. In this case, the first substrate 10 and the second substrate 20 are more closely bonded to each other at the outer edge of the wiring substrate 100, i.e., at the cut portion for cutting out the wiring substrate 100, and a larger bonding area between the first substrate 10 and the second substrate 20 can be secured. This improves bonding reliability.

[0068] FIG. 8 is a cross-sectional view showing an example of the configuration of a wiring substrate 100 according to another embodiment and a semiconductor device 300 using the wiring substrate 100 according to another embodiment. As shown in FIG. 8 , the wiring substrate 100 according to another embodiment differs from the above-described embodiment in that a second substrate 20 containing an organic material is also located on the second surface 12 side of the first substrate 10. That is, the wiring substrate 100 according to another embodiment may have second substrates 20 located on both sides of the first substrate 10 in the thickness direction. This configuration allows the amounts of deformation due to thermal expansion on both sides of the first substrate 10 to be closer than when the second substrate 20 is located on only one side of the first substrate 10, thereby reducing the possibility of the wiring substrate 100 warping. Note that the second substrate 20 located on the second surface 12 side may also be directly bonded to the first substrate 10, just like the second substrate located on the first surface 11 side.

[0069] The wiring board 100 according to other embodiments may not have the second inclined portion 18. That is, the first base material 10 may have a relatively flat configuration in which only the first inclined portion 16 located on the first surface 11 side is formed, and the second inclined portion 18 is not formed on the second surface 12 side. With this configuration, compared to when the second inclined portion 18 is formed on the second surface 12 side, the volume of the first base material 10 containing ceramic as a material with higher heat dissipation properties than the second base material 20 can be increased, and the heat capacity of the wiring board 100 can be increased.

[0070] The wiring substrate 100 according to another embodiment may have a recess 110 penetrating only the second substrate 20 located on the first surface 11 side. Furthermore, the wiring substrate 100 may have a recess 110 penetrating only the second substrate 20 located on the second surface 12 side. In other words, the first substrate 10 may be exposed at the bottom of the recess 110. In this case, the same or different types of semiconductor elements 310 may be located in each recess 110. Furthermore, elements other than the semiconductor element 310 (e.g., capacitors or inductors) may also be located in the recess 110. With this configuration, the semiconductor element 310 or other elements can be mounted on the first substrate 10 containing ceramic as a material, which has higher heat dissipation properties than the second substrate 20, thereby enabling efficient heat dissipation from each element. The semiconductor element 310 or other elements may be electrically connected to the second wiring 40 located on the second substrate 20 or to the first wiring 30 located on the first substrate 20. More specifically, the semiconductor element 310 or elements located in the recess 110 on the first surface 11 side may be electrically connected to the electrode pads 33 located on the first surface 11 by bonding wires, solder, or a conductive bonding material. Also, the semiconductor element 310 or elements located in the recess 110 on the second surface 12 side may be electrically connected to the electrode pads 33 located on the second surface 12 by bonding wires, solder, or a conductive bonding material.

[0071] The opening area of ​​the recess 110 located on the first surface 11 side and the opening area of ​​the recess 110 located on the second surface 12 side may be the same or may be different as shown in Fig. 8. The opening area of ​​the recess 110 located on the first surface 11 side and the opening area of ​​the recess 110 located on the second surface 12 side can be changed as appropriate depending on the weight and rigidity of the semiconductor element 310 or element located in the recess 110, and the entire wiring substrate 100.

[0072] 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.

[0073] 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.

[0074] The present technology can also be configured as follows: (1) A wiring board comprising: a first substrate having a first surface and a second surface opposite to the first surface, the first substrate containing an inorganic material; and a second substrate overlaid on the first surface and directly bonded to the first substrate, the second substrate containing an organic material, wherein the first surface has a first central portion and a first inclined portion located on an outer edge side of the first central portion and inclined toward the second surface as it approaches the outer edge, and the second substrate extends from the first central portion to the first inclined portion along the first surface. (2) The wiring board according to (1), comprising: a first wiring located inside the first substrate; and a second wiring located inside the second substrate and electrically connected to the first wiring at an interface between the first substrate and the second substrate, the first wiring and the second wiring being located in the first central portion at least at the interface between the first substrate and the second substrate. (3) The wiring board according to (1) or (2), wherein the first base material includes a ceramic material having hydroxyl groups on a surface thereof, and the first base material and the second base material are chemically bonded by the hydroxyl groups. (4) The wiring board according to any one of (1) to (3), wherein the second surface has a second central portion and a second inclined portion located on an outer edge side of the second central portion and inclined toward the first surface as it approaches the outer edge. (5) The wiring board according to any one of (1) to (4), wherein the first base material has a first side surface connecting the first surface and the second surface, and the second base material has a third surface bonded to the first surface, a fourth surface located opposite the third surface, and a second side surface connecting the third surface and the fourth surface, and the surface roughness of the fourth surface is smaller than the surface roughness of the first side surface and is smaller than the surface roughness of the second side surface. (6) The wiring board according to any one of (1) to (5), wherein the first base material has a first side surface connecting the first surface and the second surface, the second base material has a third surface joining to the first surface, a fourth surface located opposite the third surface, and a second side surface connecting the third surface and the fourth surface, and the surface roughness of the second surface is smaller than the surface roughness of the first side surface and is also smaller than the surface roughness of the second side surface.(7) The wiring board according to any one of (1) to (6), wherein the second base material contains a black-based organic material as a material. (8) The wiring board according to any one of (1) to (7), wherein the first base material is rectangular in a plan view, and the first inclined portions are located on each of four sides of the first base material in a plan view. (9) The wiring board according to any one of (1) to (8), wherein the second surface has a second central portion and second inclined portions located on an outer edge side of the second central portion and inclined toward the first surface as it approaches the outer edge, and the first base material is rectangular in a plan view, and the second inclined portions are located on each of four sides of the first base material in a plan view. (10) A semiconductor device comprising: the wiring board according to any one of (1) to (9); and a semiconductor element mounted on the wiring board.

[0075] REFERENCE SIGNS LIST 10 First substrate 11 First surface 12 Second surface 13 First side surface 15 First central portion 16 First inclined portion 17 Second central portion 18 Second inclined portion 19 Side 20 Second substrate 21 Third surface 22 Fourth surface 23 Second side surface 24 Organic resin layer 25 Fifth surface 26 Sixth surface 30 First wiring 31 Via 32 Wiring layer 33 Electrode pad 40 Second wiring 41 Via 50 Connecting conductor 100 Wiring substrate 110 Recess 300 Semiconductor device 310 Semiconductor element

Claims

1. A wiring board comprising: a first substrate having a first surface and a second surface opposite the first surface, the first substrate containing an inorganic material; and a second substrate overlapping the first surface and directly bonded to the first substrate, the second substrate containing an organic material, the first substrate having a first central portion and a first inclined portion located toward the outer edge of the first central portion and inclining toward the second substrate as it approaches the outer edge, the second substrate extending from the first central portion to the first inclined portion along the first substrate.

2. The wiring board according to claim 1, comprising: a first wiring located inside the first base material; and a second wiring located inside the second base material and electrically connected to the first wiring at the interface between the first base material and the second base material, wherein the first wiring and the second wiring are located in the first central portion at least at the interface between the first base material and the second base material.

3. The wiring board according to claim 1 or 2, wherein the first base material includes a ceramic material having hydroxyl groups on the surface thereof, and the first base material and the second base material are chemically bonded together by the hydroxyl groups.

4. A wiring board as described in any one of claims 1 to 3, wherein the second surface has a second central portion and a second inclined portion that is located closer to the outer edge than the second central portion and inclined toward the first surface as it moves toward the outer edge.

5. A wiring board as described in any one of claims 1 to 4, wherein the first substrate has 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 the fourth surface is smaller than the surface roughness of the first side surface and is also smaller than the surface roughness of the second side surface.

6. A wiring board as described in any one of claims 1 to 5, wherein the first substrate has 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 the second surface is smaller than the surface roughness of the first side surface and is also smaller than the surface roughness of the second side surface.

7. The wiring board according to any one of claims 1 to 6, wherein the second base material contains a black-based organic material as a material.

8. A wiring board according to any one of claims 1 to 7, wherein the first base material is rectangular in a planar view, and the first inclined portions are located on each of the four sides of the first base material in a planar view.

9. A wiring board as claimed in any one of claims 1 to 8, wherein the second surface has a second central portion and a second inclined portion located on the outer edge side of the second central portion and inclined toward the first surface as it approaches the outer edge, the first base material is rectangular in a planar view, and the second inclined portions are located on each of the four sides of the first base material in a planar view.

10. A semiconductor device comprising: a wiring board according to any one of claims 1 to 9; and a semiconductor element mounted on the wiring board.

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