Wiring board and semiconductor device

Abstract

This wiring board comprises: a first base material which has a first surface and a second surface positioned on the side opposite to the first surface and in which a ceramic composite material containing a silica component is used; a second base material which forms a laminate with the first base material, has a third surface and a fourth surface positioned on the side opposite to the third surface, and contains an organic material; and a second wiring which has a first land positioned on the first surface, a second land positioned on the third surface, and a second via conductor connected to the second land, and which extends from the third surface to the fourth surface. The second base material has a reinforcement layer that is positioned inside the second base material, contains an organic material, and has a rigidity higher than that of other portions in the second base material.

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, in the field of wiring substrates used in semiconductor devices, there has been known a technique for joining a substrate mainly made of ceramic to a substrate mainly made of organic material (see, for example, Patent Document 1).

[0003] JP 2011-9698 A

[0004] The wiring board of the present disclosure comprises a first substrate having a first surface and a second surface opposite the first surface, the first substrate being made of a ceramic composite material containing a silica component; a second substrate forming a laminate with the first substrate and having a third surface and a fourth surface opposite the third surface, the second substrate containing an organic material; a first land located on the first surface, a second land located on the third surface, and a second via conductor connected to the second land; and a second wiring extending from the third surface to the fourth surface, the second substrate having a reinforcing layer located inside the second substrate, the reinforcing layer containing an organic material, and having higher rigidity than other portions of the second substrate.

[0005] FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a wiring board according to a first embodiment. FIG. 2 is a schematic cross-sectional view showing an example of the configuration of a semiconductor device according to the first embodiment. FIG. 3 is a schematic cross-sectional view showing an example of the configuration of a wiring board according to a second embodiment. FIG. 4 is a schematic cross-sectional view showing an example of the configuration of a wiring board according to a third embodiment. FIG. 5 is a schematic cross-sectional view showing an example of the configuration of a wiring board according to a fourth embodiment. FIG. 6 is an explanatory diagram (part 1) of an example of the configuration of a semiconductor device according to the fourth embodiment. FIG. 7 is an explanatory diagram (part 2) of an example of the configuration of a semiconductor device according to the fourth 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 following embodiments, expressions such as "orthogonal" or "vertical" may be used, but these expressions do not necessarily mean "orthogonal" or "vertical" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0008] 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.

[0009] In a wiring board in which a substrate made of a ceramic composite material and a substrate made of an organic material are bonded together, there is a risk of cracks occurring in the substrate made of the organic material due to the difference in thermal expansion coefficients between the substrate made of the ceramic composite material and the substrate made of the organic material. Furthermore, there is a risk of these substrates peeling apart due to the difference in thermal expansion coefficients between the substrate made of the ceramic composite material and the substrate made of the organic material. Therefore, it is desirable to improve the reliability of a wiring board in which a substrate made of a ceramic composite material and a substrate made of an organic material are bonded together against temperature changes.

[0010] 1 is a schematic cross-sectional view showing an example of the configuration of a wiring board according to a first embodiment. As shown in FIG. 1, a wiring board 100 according to the first embodiment includes a first substrate 10, a second substrate 20, and a third substrate 30. The wiring board 100 is a laminate of the first substrate 10, the second substrate 20, and the third substrate 30. The wiring board 100 also includes a first wiring 40, a second wiring 50, and a third wiring 60.

[0011] <First Substrate> The first substrate 10 is formed using a ceramic composite material containing a silica component such as glass, that is, so-called glass ceramic. The glass ceramic may be any of a composite of a glass phase and ceramic particles, a composite of a glass phase and a crystalline phase formed by the crystallization of a portion of the glass phase, a form in which ceramic particles exist in a glass phase, and a form in which a glass phase exists at the grain boundaries between ceramic particles.

[0012] For example, the first substrate 10 may be made of low temperature co-fired ceramics (LTCC). When LTCC is used as the first substrate 10, a low-melting-point metal such as copper or silver, which has a relatively low electrical resistance, can be used as wiring.

[0013] The first substrate 10 may contain a ceramic filler as ceramic particles. Examples of the ceramic filler that can be used include alumina (aluminum oxide), calcium titanate, and magnesium titanate. The first substrate 10 containing alumina has high rigidity.

[0014] The first substrate 10 has a first surface 101 and a second surface 102 located on the opposite side of the first surface 101. The first substrate 10 may be a plate-like body having the first surface 101 and the second surface 102 as main surfaces.

[0015] In the first embodiment, the first substrate 10 has a ceramic layer 11. In the example shown in FIG. 1 , the first substrate 10 has a single-layer structure composed of one ceramic layer 11, but the first substrate 10 may have a multi-layer structure composed of multiple ceramic layers 11. The multiple ceramic layers 11 are stacked along the Z-axis direction shown in FIG. 1 , which is the thickness direction of the first substrate 10. By constructing the first substrate 10 using multiple ceramic layers 11 in this way, it is possible to obtain a first substrate 10 having a first wiring layer therein, which will be described later.

[0016] There is a high degree of freedom in designing the wiring board 100 having such a first base material 10. Furthermore, by configuring the first base material 10 using a plurality of ceramic layers 11, it is possible to manufacture the first base material 10 while checking for each layer whether the first wiring 40 described below is properly formed, thereby improving the yield of the first base material 10.

[0017] <Second Base Material> The second base material 20 is a base material that uses an organic material and contains this 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.

[0018] The organic resin may be, for example, polytetrafluoroethylene (PTFE), other fluororesins, or polyphenylene ether resin. The second substrate 20 may contain components other than the organic resin. In the present disclosure, the second substrate 20 may contain the organic resin as a material that accounts for, for example, 30% by mass or more of the material.

[0019] The second substrate 20 has a third surface 103 and a fourth surface 104 located on the opposite side of the third surface 103. The second substrate 20 may be a plate-like body having the third surface 103 and the fourth surface 104 as main surfaces.

[0020] In the first embodiment, the second substrate 20 has an organic resin layer 21. In the example shown in FIG. 1 , the second substrate 20 has a single-layer structure composed of one organic resin layer 21, but the second substrate 20 may have a multi-layer structure composed of a plurality of organic resin layers 21. The plurality of organic resin layers 21 are stacked along the Z-axis direction shown in FIG. 1 , which is the thickness direction of the second substrate 20. By configuring the second substrate 20 using a plurality of organic resin layers 21 in this way, it is possible to obtain a second substrate 20 having a second wiring layer therein, which will be described later.

[0021] The wiring board 100 having such a second base material 20 has a high degree of freedom in design. Furthermore, by configuring the second base material 20 using a plurality of organic resin layers 21, the second base material 20 can be manufactured while checking for each layer whether the second wiring 50 described below is properly formed, and therefore the yield of the second base material 20 can be improved.

[0022] <Third Base Material> The third base material 30 is a base material that uses an organic material and contains this 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.

[0023] The organic resin may be, for example, polytetrafluoroethylene (PTFE), other fluororesins, or polyphenylene ether resin. The third base material 30 may contain a component other than the organic resin. In the present disclosure, the third base material 30 may contain the organic resin as a material that accounts for, for example, 30% by mass or more of the material.

[0024] The third substrate 30 has a fifth surface 105 and a sixth surface 106 located on the opposite side of the fifth surface 105. The fifth surface 105 is bonded to the first surface 101 of the first substrate 10. The sixth surface 106 is bonded to the third surface 103 of the second substrate 20. In this way, the third substrate 30 is located between the first substrate 10 and the second substrate 20, and serves as a bonding layer that bonds the first substrate 10 and the second substrate 20 together.

[0025] In the first embodiment, the third base material 30 has an organic resin layer 31. In the example shown in Fig. 1 , the third base material 30 has a single-layer structure constituted by one organic resin layer 31, but the third base material 30 may have a multi-layer structure constituted by a plurality of organic resin layers 31. The plurality of organic resin layers 31 are stacked along the Z-axis direction shown in Fig. 1 , which is the thickness direction of the third base material 30.

[0026] The second substrate 20 and the third substrate 30 containing an organic component are easier to form fine wiring patterns on than inorganic substrates. On the other hand, the first substrate 10 made of ceramic has higher rigidity than the second substrate 20 and the third substrate 30. Furthermore, the second substrate 20 and the third substrate 30 containing an organic material have lower density than the first substrate 10.

[0027] The wiring board 100 according to the first embodiment can increase rigidity while achieving finer wiring and narrower pitches by combining the first substrate 10, the second substrate 20, and the third substrate 30. 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 and the third substrate 30 is useful for increasing the size of the board.

[0028] Furthermore, compared to a wiring board made up of only an inorganic substrate, the wiring board 100 according to the first embodiment includes the second substrate 20 and the third substrate 30, which have a lower density than the inorganic substrate, and therefore can be made lighter.

[0029] <First Wiring and Second Wiring> The first wiring 40 is located on the first substrate 10 and extends from one of the first surface 101 and the second surface 102 to the other. Note that "extending" here does not necessarily mean extending the shortest distance. The first wiring 40 is electrically connected to the third wiring 60, which will be described later, at the bonding surface with the third substrate 30. The first wiring 40 may have a first wiring layer in the middle, which is the portion that extends along the first surface 101 or the second surface 102.

[0030] The first wiring 40 has a plurality of first via conductors 41 and one or more first wiring layers (not shown). The first via conductors 41 and the first wiring layer are located inside the first substrate 10. The first via conductors 41 penetrate one or more ceramic layers 11. When there are multiple ceramic layers 11, the first wiring layer is located, for example, between adjacent ceramic layers 11 and electrically connects the multiple first via conductors 41 together.

[0031] In this way, since the wiring board 100 has the first wiring 40 on the first base material 10, the degree of freedom in wiring design is higher compared to a wiring board having wiring only on a substrate made of organic resin. On the other hand, when the first base material 10, the second base material 20, and the third base material 30 have wiring, it is desirable to bond the first base material 10, the second base material 20, and the third wiring 60 more firmly so that misalignment does not occur between the first wiring 40, the second wiring 50, and the third wiring 60.

[0032] As shown in FIG. 1, the first wiring 40 does not necessarily have to have a first wiring layer.

[0033] The first wiring 40 also has a first land 42, which is a bonding conductor, located on the first surface 101 or the second surface 102, which is the surface of the first substrate 10. The first land 42 may be a conductor containing a silica component. The first land 42 is located between the first substrate 10 and the third substrate 30, and electrically connects the first wiring 40 and the third wiring 60. A wiring board 100 having such a first land 42 has a high degree of freedom in design.

[0034] The first land 42 may contain hydroxyl groups on the surface. The first land 42 may be chemically bonded to the first base material 10 via the hydroxyl groups, and the hydroxyl groups are hydrogen-bonded to the first base material 10. This allows the first land 42 to be firmly bonded to the first base material 10. The first land 42 may also be chemically bonded to the third base material 30 via the hydroxyl groups, and the hydroxyl groups are hydrogen-bonded to the third base material 30. This allows the first land 42 to be firmly bonded to the third base material 30.

[0035] The second wiring 50 is located on the second substrate 20 and extends from one of the third surface 103 and the fourth surface 104 to the other. Note that "extending" here does not necessarily mean extending the shortest distance. The second wiring 50 is electrically connected to the third wiring 60 (described later) at the bonding surface with the third substrate 30. The second wiring 50 may have a second wiring layer in the middle, which is the portion that extends along the third surface 103 or the fourth surface 104.

[0036] The second wiring 50 has a plurality of second via conductors 51 and one or more second wiring layers (not shown). The second via conductors 51 and the second wiring layer are located inside the second base material 20. The second via conductors 51 penetrate one or more organic resin layers 21. When there are multiple organic resin layers 21, the second wiring layer is located, for example, between adjacent organic resin layers 21 and electrically connects the multiple second via conductors 51 together.

[0037] As shown in FIG. 1, the second wiring 50 does not necessarily have to have a second wiring layer.

[0038] The second wiring 50 also has a second land 52, which is a bonding conductor, located on the third surface 103 or the fourth surface 104, which is the surface of the second base material 20. The second land 52 may be a conductor containing a silica component. The second land 52 is located between the second base material 20 and the third base material 30, and electrically connects the second wiring 50 and the third wiring 60. The wiring board 100 having such a second land 52 has a high degree of freedom in design.

[0039] The first wiring 40 and the second wiring 50 may be, for example, a metal conductor whose main component is copper or silver. For example, both the first wiring 40 and the second wiring 50 may be a metal conductor whose main component is copper. Alternatively, both the first wiring 40 and the second wiring 50 may be a metal conductor whose main component is silver. Alternatively, one of the first wiring 40 and the second wiring 50 may be a metal conductor whose main component is copper, and the other may be a metal conductor whose main component is silver.

[0040] By making all of the first wiring 40 and the second wiring 50 metal conductors whose main component is copper or silver, it is possible to obtain higher electrical characteristics than, for example, when one of the first wiring 40 and the second wiring 50 is made of a metal conductor other than copper or silver.

[0041] Of the first wiring 40 and the second wiring 50, only the first wiring 40 may contain a silica component. In this case, the first wiring 40 is firmly bonded to the first base material 10, which also contains a silica component, via the silica component. This allows the rigidity of the first base material 10 to be increased.

[0042] Furthermore, in the firing step when manufacturing the wiring substrate 100, the shrinkage rates of the first base material 10 and the first wiring 40 can be made to be the same to some extent, so that the positional deviation of the first wiring 40 can be made less likely to occur.

[0043] The first wiring 40 may be formed, for example, by printing a conductive paste containing copper and silica components on a green sheet that is the raw material of the ceramic layer 11, and firing the green sheet simultaneously with the green sheet. Specifically, the conductive paste may contain, for example, copper powder, borosilicate glass powder, and silica particles.

[0044] On the other hand, the second wiring 50 may be formed by copper plating, whereby, of the first wiring 40 and the second wiring 50, only the first wiring 40 can be configured to contain a silica component.

[0045] The second wiring 50 may be electrically and thermally connected to, for example, the semiconductor element 200 (see FIG. 2 ) placed on the third surface 103 of the second base material 20. By thermally connecting the second wiring 50, which is mainly composed of copper or silver, which has a relatively high thermal conductivity, to the semiconductor element 200, which serves as a heat source, the heat from the semiconductor element 200 can be efficiently dissipated via the second wiring 50 and the first wiring 40.

[0046] <Third Wiring> The third wiring 60 is located on the third base material 30, and extends from one of the fifth surface 105 and the sixth surface 106 to the other. Note that "extending" here does not necessarily mean extending the shortest distance. The third wiring 60 is electrically joined to the first wiring 40 at the bonding surface with the first base material 10. The third wiring 60 is electrically joined to the second wiring 50 at the bonding surface with the second base material 20. The third wiring 60 may have a wiring layer in the middle that forms the portion extending along the fifth surface 105 or the sixth surface 106.

[0047] The third wiring 60 has a third via conductor 61. The third via conductor 61 penetrates one or more organic resin layers 31. The third via conductor 61 connects between the first land 42 and the second land 52. In this manner, the third via conductor 61 electrically connects the first wiring 40 and the second wiring 50. The third via conductor 61 may be a conductor whose main component is copper or a metal other than copper, such as silver.

[0048] The third via conductor 61 may have an alloy layer (not shown) at the interface with the first land 42. When the third via conductor 61 has an alloy layer at the interface with the first land 42, the alloy layer can increase the bonding strength between the first land 42 and the third via conductor 61. This can increase the connection reliability between the first wiring 40 and the third wiring 60.

[0049] <First Substrate, Second Substrate, and Third Substrate> The first substrate 10 made of a ceramic composite material has a smaller thermal expansion coefficient than the second substrate 20 containing an organic material. When the first substrate 10 and the second substrate 20 are directly bonded together, the difference in thermal expansion coefficients between the two substrates due to the heat of the semiconductor element 200 mounted on the wiring substrate 100 and other components imposes a large load on the interface between the first substrate 10 and the second substrate 20. This may result in a decrease in the bonding reliability of the substrates. Furthermore, when a third substrate 30 is provided between the first substrate 10 and the second substrate 20 as a bonding layer bonding the two substrates, the difference in thermal expansion coefficients between the first substrate 10 and the third substrate 30 and between the second substrate 20 and the third substrate 30 imposes a large load on each interface. This may result in a decrease in the bonding reliability of the substrates. Note that the thermal expansion coefficient here refers to the thermal expansion coefficient in the X-axis direction shown in FIG. 1 .

[0050] 1 , in the wiring board 100, at least a portion of the first land 42 extends into the third base material 30. At least a portion of the first land 42 in the thickness direction extends into the third base material 30. The entire first land 42 in the thickness direction may extend into the third base material 30.

[0051] By having at least a portion of the first land 42 located on the first surface 101 of the first substrate 10 extend into the third substrate 30, expansion or contraction in the X-axis direction shown in FIG. 1 , which is the direction along the fifth surface 105 or the sixth surface 106 of the third substrate 30, is suppressed. This reduces the load on the interface between the first substrate 10 and the third substrate 30, thereby improving the bonding reliability of the substrates. Furthermore, by having at least a portion of the first land 42 extend into the third substrate 30, the thickness of the wiring substrate 100 can be reduced. This allows the wiring substrate 100 to be made smaller.

[0052] 1 , in the wiring board 100, at least a portion of the second land 52 may extend into the third base material 30. At least a portion of the second land 52 in the thickness direction may extend into the third base material 30. The entire second land 52 in the thickness direction may extend into the third base material 30.

[0053] At least a portion of the second lands 52 located on the third surface 103 of the second substrate 20 extends into the third substrate 30, thereby suppressing expansion or contraction of the third substrate 30 in the X-axis direction. This reduces the load on the interface between the second substrate 20 and the third substrate 30, thereby improving the bonding reliability of the substrates. Furthermore, at least a portion of the second lands 52 extends into the third substrate 30, thereby reducing the thickness of the wiring substrate 100. This allows the wiring substrate 100 to be miniaturized.

[0054] 1 , in the wiring substrate 100, the thickness of the first lands 42 may be greater than the thickness of the second lands 52. This allows the first lands 42 to penetrate deeper into the third base material 30, making the bond between the first base material 10 and the third base material 30 stronger and further increasing the ability to suppress expansion or contraction of the third base material 30 in the X-axis direction.

[0055] Furthermore, when the first land 42 extends into the third base material 30, for example, if the outer periphery of the first land 42 is perpendicular to the first surface 101, a gap may be generated around the outer periphery. If such a gap is generated, the bonding strength between the first base material 10 and the third base material 30 may be reduced.

[0056] 1 , in the wiring substrate 100, the outer periphery of the first land 42 may have a first inclined surface 421 that is an inclined surface that approaches the first surface 101 of the first base material 10 the further outward. By having such a first inclined surface 421, the first land 42 and the third base material 30 can be closely attached to each other. This makes it possible to prevent voids from being generated around the outer periphery of the first land 42 and to increase the bonding area between the first land 42 and the third base material 30, thereby increasing the bonding strength between the first base material 10 and the third base material 30.

[0057] Furthermore, the thermal expansion coefficient of the third base material 30 may be greater than the thermal expansion coefficient of the first base material 10 and less than the thermal expansion coefficient of the second base material 20 .

[0058] In this way, the first substrate 10, the second substrate 20, and the third substrate 30 have a thermal expansion coefficient magnitude relationship of "first substrate < third substrate < second substrate," so the difference in thermal expansion coefficient between the first substrate 10 and the third substrate 30 and between the second substrate 20 and the third substrate 30 is small. This makes it possible to reduce the load on the interface between the first substrate 10 and the third substrate 30 and the interface between the second substrate 20 and the third substrate 30, and to improve the bonding reliability of the substrates.

[0059] 1 , the wiring substrate 100 has a plurality of convex bodies 70. The plurality of convex bodies 70 protrude from the first surface 101 of the first substrate 10 toward the third substrate 30 and extend into the interior of the third substrate 30.

[0060] Thus, with the wiring substrate 100, the bonding strength between the first substrate 10 and the third substrate 30 can be increased by an anchor effect that occurs when the multiple convex bodies 70 penetrate into the third substrate 30. By firmly bonding the third substrate 30 to the first substrate 10, it is possible to suppress expansion or contraction of the third substrate 30 in the X-axis direction, and it is possible to alleviate the load on the interface between the first substrate 10 and the third substrate 30.

[0061] By firmly bonding the third substrate 30 to the first substrate 10, the third substrate 30 is constrained by the first substrate 10, and deformation due to thermal expansion of the third substrate 30 is reduced. As a result, deformation due to thermal expansion of the third substrate 30 is reduced even at positions other than the positions where the first lands 42 extend into the third substrate 30.

[0062] The convex bodies 70 contain a silica component and are bonded to the first substrate 10 by the silica component.

[0063] In this way, the plurality of convex bodies 70 are firmly bonded to the first substrate 10 containing a silica component. This makes the bond between the first substrate 10 and the third substrate 30 stronger, making it even less likely that the first substrate 10 and the third substrate 30 will become misaligned. This stabilizes the physical connection between the first wiring 40 and the third wiring 60.

[0064] Furthermore, the convex body 70 firmly bonded to the first substrate 10 is unlikely to come off the first substrate 10 even when repeatedly subjected to loads caused by thermal expansion of the third substrate 30. Therefore, according to the wiring substrate 100, the first substrate 10 and the third substrate 30 can be maintained in a firmly bonded state for a long period of time.

[0065] <Semiconductor Device> Fig. 2 is a schematic cross-sectional view showing an example of the configuration of a semiconductor device according to the first embodiment. As shown in Fig. 2, a semiconductor device 300 according to the first embodiment includes a wiring substrate 100 and a semiconductor element 200. The semiconductor element 200 is mounted on the fourth surface 104 of the second base material 20 of the wiring substrate 100. In this mounting, a silicon interposer or the like is provided between the semiconductor element 200 and the wiring substrate 100.

[0066] In semiconductor devices, the difference in thermal expansion coefficients between the first and third substrates and between the second and third substrates due to the heat generated by the semiconductor element places a large load on the respective interfaces. This can reduce the bonding reliability of the substrates. Note that the thermal expansion coefficient here refers to the thermal expansion coefficient in the X-axis direction shown in Figure 1.

[0067] However, in the semiconductor device 300 according to the first embodiment, at least a portion of the first lands 42 located on the first surface 101 of the first substrate 10 in the wiring substrate 100 extends into the third substrate 30, thereby suppressing expansion or contraction in the X-axis direction shown in FIG. 1 , which is the direction along the fifth surface 105 or the sixth surface 106 of the third substrate 30. This reduces the load on the interface between the first substrate 10 and the third substrate 30, thereby improving the bonding reliability of the substrates. Furthermore, since at least a portion of the first lands 42 extends into the third substrate 30, the thickness of the wiring substrate 100 can be reduced. This enables the wiring substrate 100 to be miniaturized.

[0068] Second Embodiment In the above-described first embodiment, an example has been described in which the first lands 42 of the wiring substrate 100 extend into the third base material 30. The wiring substrate 100 is not limited to this, and a part of the first lands 42 located on the first surface 101 may extend into the third base material 30, and a part of the first lands 42 may extend into the first base material 10.

[0069] 3 is a schematic cross-sectional view showing an example of the configuration of a wiring board according to the second embodiment. As shown in FIG. 3 , in the wiring board 100 according to the second embodiment, at least a portion of the first lands 42 extends into the first substrate 10, thereby further suppressing expansion or contraction of the third substrate 30. This reduces the load on the interface between the first substrate 10 and the third substrate 30, thereby improving the bonding reliability of the substrates. Furthermore, since a portion of the first lands 42 extends into the first substrate 10, the thickness of the wiring board 100 can be further reduced. This allows the wiring board 100 to be miniaturized.

[0070] Furthermore, in the first embodiment described above, the wiring substrate 100 has a first inclined surface 421, which is an inclined surface that approaches the first surface 101 of the first base material 10 as the outer periphery of the first land 42 moves outward. The wiring substrate 100 is not limited to this, and may have a second inclined surface 422, which is an inclined surface that approaches the fifth surface 105 as the outer periphery of the first land 42 moves outward, as in the wiring substrate 100 according to the second embodiment.

[0071] The provision of such a second inclined surface 422 allows the first land 42 and the first substrate 10 to be in close contact with each other. This makes it possible to prevent gaps from being generated around the outer periphery of the first land 42 and to increase the bonding area between the first land 42 and the first substrate 10, thereby increasing the bonding strength between the first substrate 10 and the third substrate 30.

[0072] 4 is a schematic cross-sectional view showing an example of the configuration of a wiring board according to a third embodiment. As shown in Fig. 4, in the wiring board 100 according to the third embodiment, the third base material 30 may incorporate components 210 to be mounted on the wiring board 100. Examples of the components 210 incorporated in the third base material 30 include capacitors and other chip components.

[0073] Since the component 210 is embedded in the third base material 30, it is possible to miniaturize a semiconductor device using the wiring board 100.

[0074] The third via conductor 61 may be a conductor whose main component is copper or a metal other than copper, such as silver. The third base material 30 may have a multilayer structure composed of multiple organic resin layers 31 and may have interlayer wiring. In this case, the interlayer wiring is formed of copper foil.

[0075] Since the component 210 is embedded in the third base material 30, it is possible to miniaturize a semiconductor device using the wiring board 100.

[0076] 5 is a schematic cross-sectional view showing an example of the configuration of a wiring board according to a fourth embodiment. The fourth embodiment described below differs in configuration from the first to third embodiments described above mainly in that it includes a reinforcing layer 22, which will be described later.

[0077] 5 , the wiring substrate 100 according to the fourth embodiment includes a first substrate 10, a second substrate 20, and a third substrate 30. The wiring substrate 100 is a laminate of the first substrate 10, the second substrate 20, and the third substrate 30. The wiring substrate 100 also includes a first wiring 40, a second wiring 50, and a third wiring 60.

[0078] In the wiring board 100 according to the fourth embodiment, the second base material 20 includes a reinforcing layer 22. The reinforcing layer 22 is made of an organic material and is a base material containing this 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.

[0079] The organic resin may be, for example, polytetrafluoroethylene (PTFE), other fluororesins, or polyphenylene ether resin. The reinforcing layer 22 may contain components other than the organic resin. The reinforcing layer 22 may be a so-called glass cloth, in which glass fiber, which is glass processed into a fibrous form, is mixed into the organic resin.

[0080] The reinforcing layer 22 has higher rigidity than the organic resin layer 21 that constitutes the other portion of the second base material 20. Since the reinforcing layer 22 is made of glass cloth, the reinforcing layer 22 has higher rigidity than the organic resin layer 21 that constitutes the other portion of the second base material 20.

[0081] The reinforcing layer 22 may be made of the above-mentioned organic resin mixed with a glass material. In this way, even if the reinforcing layer 22 is an organic resin layer mixed with a glass material, the rigidity thereof will be higher than that of the organic resin layer 21 that constitutes the other portion of the second base material 20. The reinforcing layer 22 may be made of the above-mentioned organic resin mixed with a ceramic. In this way, even if the reinforcing layer 22 is an organic resin layer mixed with a ceramic, the rigidity thereof will be higher than that of the organic resin layer 21 that constitutes the other portion of the second base material 20.

[0082] The reinforcing layer 22 has a seventh surface 107 and an eighth surface 108 located on the opposite side of the seventh surface 107. The seventh surface 107 is bonded to a ninth surface 109 of the second substrate 20. The eighth surface 108 is bonded to a tenth surface 110 of the second substrate 20. In this manner, the reinforcing layer 22 is located between predetermined organic resin layers 21 of the second substrate 20. In other words, the reinforcing layer 22 is located inside the second substrate 20.

[0083] As described above, the first substrate 10 using a ceramic composite material has a smaller coefficient of thermal expansion than the second substrate 20 containing an organic material. When the first substrate 10 and the second substrate 20 are bonded together, stress caused by the difference in the coefficients of thermal expansion between the two substrates due to the heat of a semiconductor element or the like mounted on the substrate may cause cracks, particularly in the second substrate 20. Here, the coefficient of thermal expansion refers to the coefficient of thermal expansion in the X-axis direction shown in FIG. 5 .

[0084] In the wiring board 100 according to the fourth embodiment, the reinforcing layer 22 having higher rigidity than the second substrate 20 is located inside the second substrate 20, thereby reinforcing the second substrate 20 against stress caused by the difference in thermal expansion coefficient between the first substrate 10 and the second substrate 20. This improves the reliability of the wiring board 100 against temperature changes.

[0085] Furthermore, since the reinforcing layer 22, which has higher rigidity than the second substrate 20, is located inside the second substrate 20, expansion or contraction due to thermal expansion of the second substrate 20 is suppressed. This reduces the difference in thermal expansion coefficient between the first substrate 10 and the second substrate 20. This makes it possible to alleviate the load on the interface between the first substrate 10 and the second substrate 20.

[0086] Furthermore, since strength is ensured even if the number of via holes (not shown) in the second base material 20 increases, it is possible to increase the wiring density in the second base material 20. In other words, it is possible to densely arrange the wiring in the second base material 20.

[0087] Furthermore, finer wiring is possible in the second substrate 20 containing an organic material than in a wiring board made only of the first substrate 10 using a ceramic composite material. Also, weight can be reduced compared to a wiring board made only of the first substrate 10 using a ceramic composite material.

[0088] Furthermore, since the reinforcing layer 22 is made of glass cloth, the strength of the reinforcing layer 22 can be increased compared to other portions of the second substrate 20. Furthermore, since the reinforcing layer 22 is located inside the second substrate 20, the strength of the second substrate 20 can be increased.

[0089] In the example shown in Fig. 5, the second substrate 20 has a multilayer structure composed of a plurality of organic resin layers 21. The plurality of organic resin layers 21 are stacked along the Z-axis direction shown in Fig. 5, which is the thickness direction of the second substrate 20. The second substrate 20 may have a single-layer structure composed of one organic resin layer 21 on the seventh surface 107 side of the reinforcing layer 22. The second substrate 20 may also have a single-layer structure composed of one organic resin layer 21 on the eighth surface 108 side of the reinforcing layer 22.

[0090] The dimension of the reinforcing layer 22 in the thickness direction is smaller than the dimension of the first base material 10 in the thickness direction. The dimension of the entire second base material 20 including the reinforcing layer 22 in the thickness direction is smaller than the dimension of the first base material 10 in the thickness direction.

[0091] 5 , i.e., penetrating from the seventh surface 107 to the eighth surface 108. The second via conductors 51 of the second substrate 20 are located in the reinforcing layer 22. The second via conductors 51 are located in the reinforcing layer 22, thereby increasing the wiring density of the second substrate 20. The outer surfaces of the second via conductors 51 are, for example, copper-plated.

[0092] Also in the fourth embodiment, the third substrate 30, which is located between the first substrate 10 and the second substrate 20 and serves as a bonding layer that bonds the two substrates, the first substrate 10 and the second substrate 20, has an organic resin layer 31. In the example shown in Fig. 5 , the third substrate 30 has a single-layer structure constituted by one organic resin layer 31, but the third substrate 30 may have a multi-layer structure constituted by a plurality of organic resin layers 31. The plurality of organic resin layers 31 are stacked along the Z-axis direction shown in Fig. 5 , which is the thickness direction of the third substrate 30.

[0093] The configuration may not include the third base material 30 that joins the first base material 10 and the second base material 20. When the third base material 30 is not included, the first base material 10 and the second base material 20 may be joined by solder, for example.

[0094] Such a third substrate 30 can reduce the difference in thermal expansion coefficient between the first substrate 10 and the second substrate 20. This can reduce the load on the interface between the first substrate 10 and the second substrate 20, thereby improving the bonding reliability of the substrates.

[0095] Furthermore, the second substrate 20 and the third substrate 30 containing an organic component are easier to form fine wiring patterns on than inorganic substrates. On the other hand, the first substrate 10 made of ceramic has higher rigidity than the second substrate 20 and the third substrate 30. Furthermore, the second substrate 20 and the third substrate 30 containing an organic material have lower density than the first substrate 10.

[0096] The wiring board 100 according to the fourth embodiment can increase rigidity while achieving finer wiring and narrower pitches by combining the first substrate 10, the second substrate 20, and the third substrate 30. 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 and the third substrate 30 is useful for increasing the size of the board.

[0097] Furthermore, the wiring board 100 according to the fourth embodiment can be made lighter than a wiring board made up of only an inorganic substrate because it includes the second substrate 20 and the third substrate 30, which have a lower density than the inorganic substrate.

[0098] Furthermore, in the wiring board 100 according to the fourth embodiment, at least a portion of the first land 42 in the thickness direction may extend into the third base material 30. In this case, the first land 42 may have a first inclined surface 421. The first inclined surface 421 is an inclined surface that approaches the first surface 101 as the outer periphery of the first land 42 moves outward.

[0099] At least a portion of the first land 42 in the thickness direction may extend into the first base material 10. In this case, the first land 42 may have a second inclined surface 422. The second inclined surface 422 is an inclined surface that approaches the fifth surface 105 as the outer periphery of the first land 42 moves outward. Note that the entire first land 42 in the thickness direction may extend into the third base material 30. In this case, the first land 42 may have only the first inclined surface 421.

[0100] At least a portion of the first land 42 located on the first surface 101 of the first substrate 10 penetrates into the third substrate 30, thereby suppressing expansion or contraction of the third substrate 30. This can reduce the load on the interface between the first substrate 10 and the third substrate 30, thereby improving the bonding reliability of the substrates.

[0101] Furthermore, since at least a portion of the first land 42 is recessed inside the third base material 30, the dimension of the substrate in the thickness direction can be reduced, thereby enabling the substrate to be made smaller.

[0102] Furthermore, since the outer periphery of the first land 42 has the first inclined surface 421 that approaches the first surface 101 as it extends outward toward the first surface 101, the first land 42 can be tightly attached to the third base material 30. This makes it possible to prevent voids from being generated around the outer periphery of the first land 42 and to increase the bonding area between the first land 42 and the third base material 30, thereby increasing the bonding strength between the first base material 10 and the third base material 30.

[0103] Furthermore, since the outer periphery of the first land 42 has the second inclined surface 422 that approaches the fifth surface 105 as it extends outward toward the fifth surface 105, the first land 42 can be tightly attached to the first base material 10. This makes it possible to prevent a gap from being generated around the outer periphery of the first land 42 and to increase the bonding area between the first land 42 and the first base material 10, thereby increasing the bonding strength between the first base material 10 and the third base material 30.

[0104] Furthermore, in the wiring board 100 according to the fourth embodiment, at least a portion of the second land 52 in the thickness direction may extend into the third base material 30. In this case, the second land 52 may have a third inclined surface 521. The third inclined surface 521 is an inclined surface that approaches the third surface 103 as the outer periphery of the second land 52 moves outward.

[0105] At least a portion of the second land 52 in the thickness direction may extend into the second base material 20. In this case, the second land 52 may have a fourth inclined surface 522. The fourth inclined surface 522 is an inclined surface that approaches the sixth surface 106 as the outer periphery of the second land 52 extends outward. Note that the entire second land 52 in the thickness direction may extend into the third base material 30. In this case, the second land 52 may have only the third inclined surface 521.

[0106] At least a portion of the second land 52 located on the third surface 103 of the second substrate 20 penetrates into the third substrate 30, thereby suppressing expansion or contraction of the third substrate 30. This can reduce the load on the interface between the second substrate 20 and the third substrate 30, thereby improving the bonding reliability of the substrates.

[0107] The thickness dimension of the substrate can be reduced by having at least a portion of the second land 52 extend into the third base material 30. This allows the substrate to be made smaller.

[0108] The outer periphery of the second land 52 has the third inclined surface 521 that approaches the third surface 103 as it extends outward toward the third surface 103, thereby making it possible to closely contact the second land 52 with the third base material 30. This makes it possible to prevent a gap from being generated around the outer periphery of the second land 52 and to increase the bonding area between the second land 52 and the third base material 30, thereby increasing the bonding strength between the second base material 20 and the third base material 30.

[0109] Furthermore, since the outer periphery of the second land 52 has the fourth inclined surface 522 that approaches the sixth surface 106 as it extends outward toward the sixth surface 106, the second land 52 can be tightly attached to the second base material 20. This makes it possible to prevent a gap from being generated around the outer periphery of the second land 52 and to increase the bonding area between the second land 52 and the second base material 20, thereby increasing the bonding strength between the second base material 20 and the third base material 30.

[0110] Furthermore, the wiring board 100 according to the fourth embodiment has second wiring 50 that forms interlayer wiring in the second base material 20, and also has first wiring 40 that forms interlayer wiring in the first base material 10 that uses a ceramic composite material. This makes it possible to reduce the number of organic resin layers 21 that form interlayer wiring in the second base material 20 that contains an organic material.

[0111] 6 and 7 are explanatory views of an example of the configuration of a semiconductor device according to the fourth embodiment. Fig. 6 is a schematic cross-sectional view showing an example of the configuration of a semiconductor device 300 according to the fourth embodiment. Fig. 7 is a schematic plan view showing an example of the configuration of a semiconductor device 300 according to the fourth embodiment. Note that the semiconductor element 200 is omitted in Fig. 7.

[0112] 6 , a semiconductor device 300 according to the fourth embodiment includes a wiring substrate 100 and a semiconductor element 200. The semiconductor element 200 is mounted on a fourth surface 104 of a second base material 20 of the wiring substrate 100. In such mounting, a silicon interposer or the like may be provided between the semiconductor element 200 and the wiring substrate 100.

[0113] For example, in a semiconductor device, the difference in the thermal expansion coefficients between the first and third substrates and between the second and third substrates due to the heat generated by the semiconductor element places a large load on the respective interfaces. This can reduce the bonding reliability of the substrates. Note that the thermal expansion coefficients here refer to the thermal expansion coefficients in the X-axis direction shown in Figures 6 and 7.

[0114] However, in the semiconductor device 300 according to the fourth embodiment, a reinforcing layer 22 having higher rigidity than the second substrate 20 is located inside the second substrate 20. This allows the second substrate 20 to be reinforced against stress caused by the difference in thermal expansion coefficient between the first substrate 10 and the second substrate 20, making the second substrate less likely to be damaged. In other words, the substrate is less likely to be damaged by stress caused by the difference in thermal expansion coefficient between different types of substrates.

[0115] Furthermore, by positioning the reinforcing layer 22, which has higher rigidity than the second substrate 20, inside the second substrate 20, expansion or contraction due to thermal expansion of the second substrate 20 is suppressed. This reduces the difference in thermal expansion coefficient between the two substrates, the first substrate 10 and the second substrate 20. This makes it possible to alleviate the load on the interface between the first substrate 10 and the second substrate 20, and improve the bonding reliability of the substrates.

[0116] Furthermore, since strength is ensured even if the number of via holes (not shown) in the second base material 20 increases, it is possible to increase the wiring density in the second base material 20. In other words, it is possible to densely arrange the wiring in the second base material 20.

[0117] Furthermore, finer wiring is possible in the second substrate 20 containing an organic material than in a wiring board made only of the first substrate 10 using a ceramic composite material. Also, weight can be reduced compared to a wiring board made only of the first substrate 10 using a ceramic composite material.

[0118] 6 , the semiconductor device 300 according to the fourth embodiment is formed by stacking a first substrate 10, a third substrate 30, and a second substrate 20 on an organic board 250 in this order from the side closest to the organic board 250. The organic board 250 is, for example, a motherboard. A semiconductor element 200 is mounted on the second substrate 20. In the semiconductor device 300 according to the fourth embodiment, the spacing between the wiring may be different for each substrate from the organic board 250 side toward the semiconductor element 200 side.

[0119] In the semiconductor device 300 according to the fourth embodiment, the wiring may be arranged at a narrower pitch for each base material from the organic board 250 side toward the semiconductor element 200 side, as indicated by the arrows in Fig. 6. In other words, in the semiconductor device 300, the wiring may be arranged at a gradually narrower pitch from the organic board 250 side toward the semiconductor element 200 side.

[0120] 6 and 7 , in the semiconductor device 300 according to the fourth embodiment, the first substrate 10 may have a region A1 where the second substrate 20 is not stacked. In FIG. 6 , the region A1 where the second substrate 20 is not stacked is shown surrounded by a dashed line. In FIG. 7 , the region A1 is shown by dots. By locating the region A1 where the second substrate 20 is not stacked on the first surface 101 of the first substrate 10, the heat dissipation properties of the wiring substrate 100 can be improved.

[0121] Other Embodiments The above-described wiring substrate 100 can be modified into various shapes. For example, the wiring substrate 100 may have a through-hole that penetrates from the first substrate 10 to the second substrate 20 in the center of a plane perpendicular to the thickness direction of the wiring substrate 100.

[0122] Furthermore, the material of the first substrate 10 is not limited to LTCC. For example, aluminum oxide or aluminum nitride may be used as the first substrate 10.

[0123] 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.

[0124] 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.

[0125] The present technology may 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 being made of a ceramic composite material containing a silica component; a second substrate forming a laminate with the first substrate, having a third surface and a fourth surface opposite to the third surface, the second substrate containing an organic material; and a second wiring having a first land located on the first surface, a second land located on the third surface, and a second via conductor connected to the second land, the second wiring extending from the third surface to the fourth surface, the second substrate having a reinforcing layer located inside the second substrate, the reinforcing layer containing the organic material, and having higher rigidity than other portions of the second substrate. (2) The wiring board according to (1), wherein the reinforcing layer is glass cloth. (3) The wiring board according to (2), wherein the second via conductor penetrating the reinforcing layer is located in the reinforcing layer. (4) The wiring board according to any one of (1) to (3), comprising: a third base material containing an organic material, the third base material having a fifth surface bonded to the first surface and a sixth surface located opposite the fifth surface and bonded to the third surface; and a third via conductor located on the third base material, connecting the first land and the second land. (5) The wiring board according to (4), wherein at least a portion of the first land extends into the third base material, and the first land has a first inclined surface that is an inclined surface that approaches the first surface as the outer periphery of the first land extends outward. (6) The wiring board according to (4) or (5), wherein at least a portion of the first land extends into the first base material, and the first land has a second inclined surface that is an inclined surface that approaches the fifth surface as the outer periphery of the first land extends outward. (7) The wiring board according to any one of (4) to (6), wherein at least a portion of the second land is embedded inside the third base material, and the second land has a third inclined surface that is an inclined surface that approaches the third surface as the outer periphery of the second land moves outward.(8) The wiring board according to any one of (4) to (7), wherein at least a portion of the second land extends into the second base material, and the second land has a fourth inclined surface that is an inclined surface that approaches the sixth surface as the outer periphery of the second land moves outward. (9) The wiring board according to any one of (1) to (8), comprising: a first wiring that has the first land and a first via conductor connected to the first land and extends from the first surface to the second surface. (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.

[0126] REFERENCE SIGNS 10 First substrate 20 Second substrate 22 Reinforcing layer 30 Third substrate 40 First wiring 42 First land 50 Second wiring 51 Second via conductor 52 Second land 61 Third via conductor 100 Wiring board 101 First surface 102 Second surface 103 Third surface 104 Fourth surface 105 Fifth surface 106 Sixth surface 200 Semiconductor element 300 Semiconductor device 421 First inclined surface 422 Second inclined surface 521 Third inclined surface 522 Fourth inclined surface

Claims

1. A wiring board comprising: a first substrate having a first surface and a second surface opposite the first surface, the first substrate being made of a ceramic composite material containing a silica component; a second substrate forming a laminate with the first substrate, having a third surface and a fourth surface opposite the third surface, the second substrate containing an organic material; and a second wiring having a first land located on the first surface, a second land located on the third surface, and a second via conductor connected to the second land, the second wiring extending from the third surface to the fourth surface, the second substrate being located inside the second substrate, the second substrate containing an organic material, and having a reinforcing layer with higher rigidity than other portions of the second substrate.

2. The wiring board according to claim 1, wherein the reinforcing layer is glass cloth.

3. The wiring board according to claim 2, wherein the second via conductors penetrating the reinforcing layer are located in the reinforcing layer.

4. A wiring board according to any one of claims 1 to 3, comprising: a third base material containing an organic material, the third base material having a fifth surface bonded to said first surface and a sixth surface located opposite said fifth surface and bonded to said third surface; and a third via conductor located on said third base material, connecting between said first land and said second land.

5. The wiring board according to claim 4, wherein at least a portion of the first land extends into the interior of the third base material, and the first land has a first inclined surface that approaches the first surface as the outer periphery of the first land moves outward.

6. The wiring board according to claim 4 or 5, wherein at least a portion of the first land extends into the interior of the first base material, and the first land has a second inclined surface that approaches the fifth surface as the outer periphery of the first land extends outward.

7. A wiring board according to any one of claims 4 to 6, wherein at least a portion of the second land extends into the interior of the third base material, and the second land has a third inclined surface that approaches the third surface as the outer periphery of the second land moves outward.

8. A wiring board according to any one of claims 4 to 7, wherein at least a portion of the second land extends into the interior of the second base material, and the second land has a fourth inclined surface that is an inclined surface that approaches the sixth surface as the outer periphery of the second land moves outward.

9. A wiring board according to any one of claims 1 to 8, comprising a first wiring having the first land and a first via conductor connected to the first land, and extending from the first surface to the second surface.

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

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