Wiring board and semiconductor device

Abstract

To reduce warpage of a wiring board due to a difference in thermal expansion coefficient.SOLUTION: The wiring board includes an inorganic substrate, a first wiring layer, a first organic substrate, and a second organic substrate. The inorganic substrate includes a plurality of inorganic layers based on a low temperature co-fired ceramic. The first wiring layer is located between two adjacent inorganic layers. The first organic substrate includes a plurality of first organic layers containing an organic component as a main component, and is bonded to the first surface of the inorganic substrate. The second organic substrate contains an organic component as a main component, and is joined to a second surface of the inorganic substrate located opposite to the first surface. The thermal expansion coefficient of the first organic substrate is larger than the thermal expansion coefficient of the inorganic substrate, and the thermal expansion coefficient of the second organic substrate is larger than the thermal expansion coefficient of the inorganic substrate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] BACKGROUND ART A wiring board is known in which organic layers including a wiring layer are laminated on a ceramic base material as a core layer (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-179816 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned wiring board, when LTCC (Low Temperature Co-fired Ceramics) is used as the ceramic base material, there is a concern that the wiring board may warp due to the difference in thermal expansion coefficient between the organic layer and the LTCC.

[0005] The present disclosure provides a technique that can reduce warpage of a wiring board due to differences in thermal expansion coefficients. [Means for solving the problem]

[0006] The wiring board of the present disclosure includes an inorganic base material, a first wiring layer, a first organic base material, and a second organic base material. The inorganic base material includes multiple inorganic layers primarily composed of low-temperature co-fired ceramic. The first wiring layer is located between two adjacent inorganic layers. The first organic base material includes multiple first organic layers primarily composed of an organic component and is bonded to a first surface of the inorganic base material. The second organic base material is primarily composed of an organic component and is bonded to a second surface of the inorganic base material opposite the first surface. The thermal expansion coefficient of the first organic base material is greater than that of the inorganic base material, and the thermal expansion coefficient of the second organic base material is greater than that of the inorganic base material. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to reduce warpage of a wiring board due to differences in thermal expansion coefficients. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the configuration of a wiring board according to an embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view showing the configuration of the first organic base material side of the wiring board according to the embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view showing the configuration of the second organic base material side of the wiring board according to the embodiment. [Figure 4] FIG. 4 is an enlarged cross-sectional view showing an example of the configuration of the H1 portion shown in FIG. [Figure 5] FIG. 5 is an enlarged cross-sectional view showing an example of the configuration of the H2 portion shown in FIG. [Figure 6] FIG. 6 is a schematic cross-sectional view illustrating the wiring pitch, the horizontal width of the inorganic base material, and the horizontal width of the first organic base material. DETAILED DESCRIPTION OF THE INVENTION

[0009] 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 within the scope of not causing any contradiction in the processing content. Furthermore, the same components in the following embodiments will be given the same reference numerals, and redundant explanations will be omitted.

[0010] Furthermore, in the following embodiments, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "perpendicular," or "parallel" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0011] In addition, in the drawings referred to below, for ease of understanding, an orthogonal coordinate system may be shown in which the X-axis, Y-axis, and Z-axis directions are defined as being perpendicular to each other, and the positive Z-axis direction is the vertically upward direction.

[0012] First, the configuration of a wiring board 1 according to the embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing the configuration of a wiring board 1 according to the embodiment.

[0013] 1, the wiring substrate 1 has an inorganic base material 10, a first organic base material 20, a second organic base material 30, and bonding layers 25 and 27. The wiring substrate 1 is a laminate of the inorganic base material 10, the first organic base material 20, and the second organic base material 30.

[0014] <Inorganic base material> The inorganic substrate 10 is a substrate whose main component is ceramic. The inorganic substrate 10 may be formed using a ceramic composite material containing a glass component, known as glass ceramic. The glass ceramic may be any of the following: a composite of a glass phase and ceramic particles; a composite of a glass phase and a crystalline phase formed by partial crystallization of the glass phase; a composite in which ceramic particles exist in the glass phase; and a composite in which a glass phase exists at the grain boundaries between ceramic particles. The inorganic substrate 10 formed using ceramic in this manner has higher rigidity than a glass core material.

[0015] For example, the inorganic base material 10 is mainly composed of LTCC (Low Temperature Co-fired Ceramics). When LTCC is used as the inorganic base material 10, the inorganic base material 10 can be fired at a low temperature, and therefore, a low-melting-point metal such as copper or silver, which has a relatively low electrical resistance, can be used as wiring. In this embodiment, a low-melting-point metal is a metal with a melting point lower than that of typical metals used for wiring in ceramic base materials, such as tungsten or molybdenum.

[0016] The inorganic 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. In particular, an inorganic substrate 10 containing alumina has high rigidity.

[0017] The inorganic substrate 10 has a first surface 101 and a second surface 102 located opposite the first surface 101. The inorganic substrate 10 may be a plate-like body having the first surface 101 and the second surface 102 as main surfaces.

[0018] In an embodiment, the inorganic substrate 10 may have a plurality of inorganic layers 11. In the examples shown in Figures 1 and 3, the inorganic substrate 10 has three inorganic layers 11, but the number of inorganic layers 11 is not limited to three. The number of inorganic layers 11 may be two, four or more.

[0019] The multiple inorganic layers 11 may include a first surface layer 111, a second surface layer 112, and an inner layer 113. The first surface layer 111 is an inorganic layer 11 having a first surface 101. In other words, the first surface layer 111 is an inorganic layer of the multiple inorganic layers 11 that is bonded to the bonding layer 25. The second surface layer 112 is an inorganic layer 11 having a second surface 102. In other words, the second surface layer 112 is an inorganic layer 11 located opposite the first surface layer 111 with the inner layer 113 in between. The inner layer 113 is an inorganic layer located between the first surface layer 111 and the second surface layer 112.

[0020] The inorganic layers 11 are stacked along the thickness direction of the inorganic base material 10. A wiring board 1 having such an inorganic base material 10 has a high degree of freedom in design. Furthermore, by configuring the inorganic base material 10 using a plurality of inorganic layers 11, the inorganic base material 10 can be manufactured while checking whether the first wiring layer 36 is properly formed for each layer, thereby improving the yield of the inorganic base material 10.

[0021] In wiring board 1, inorganic base material 10 may incorporate components (not shown) to be mounted on wiring board 1. Components that may be incorporated into inorganic base material 10 include capacitors and other chip components. Since components are incorporated into inorganic base material 10, semiconductor devices using wiring board 1 can be miniaturized.

[0022] <First organic base material> The first organic base material 20 may include a main portion 21 including a plurality of first organic layers 22, and a bonding layer 25 located between the main portion 21 and the inorganic base material 10.

[0023] The main portion 21 is mainly composed of a first organic component. The main portion 21 has a higher thermal expansion coefficient than the inorganic base material 10. The first organic component may be an organic resin. The organic resin may be, for example, an epoxy resin, a polyimide resin, an acrylic resin, a polycarbonate resin, an olefin resin, or a polyphenylene resin.

[0024] The organic resin may be, for example, polytetrafluoroethylene (PTFE) or other fluororesin or polyphenylene ether resin. The main portion 21 may contain components other than the organic resin. In this disclosure, a main component is, for example, a material that accounts for 50% or more by volume of the material.

[0025] The main portion 21 containing the first organic component as a main component is easier to form a fine wiring pattern on than the inorganic base material 10. On the other hand, the inorganic base material 10 made of ceramic has higher rigidity than the main portion 21. The inorganic base material 10 may have a higher density than the main portion 21.

[0026] The main portion 21 has a fifth surface 105 and a sixth surface 106 located opposite the fifth surface 105. The main portion 21 may be a plate-like body having the fifth surface 105 and the sixth surface 106 as main surfaces.

[0027] The bonding layer 25 is a layer located between the inorganic base material 10 and the main portion 21 and bonds to the inorganic base material 10 and the main portion 21, respectively. The bonding layer 25 contains a third organic component. The bonding layer 25 has a higher thermal expansion coefficient than the inorganic base material 10. The third organic component may be an organic resin. The organic resin may be, for example, a thermosetting resin such as an epoxy resin, a polyimide resin, an acrylic resin, or an olefin resin. The organic resin is not limited to a thermosetting resin, and may be a polycarbonate resin, a polyphenylene resin, or the like. The organic resin contained in the bonding layer 25 may be the same as the organic resin contained in the main portion 21 described above.

[0028] The bonding layer 25 may have a third surface 103 and a fourth surface 104 located opposite the third surface 103. The bonding layer 25 may be a plate-like body having the third surface 103 and the fourth surface 104 as main surfaces.

[0029] The main portion 21 is bonded to the first surface 101 of the inorganic base material 10 via the bonding layer 25. The main portion 21, which is located on the first surface 101 of the inorganic base material 10 via the bonding layer 25, may have a sixth surface 106 on which a semiconductor element 3 is placed, and a fifth surface 105 of the main portion 21 may be bonded to a fourth surface 104 of the bonding layer 25. A third surface 103 of the bonding layer 25 may be bonded to the first surface 101 of the inorganic base material 10.

[0030] The main portion 21 may have a plurality of first organic layers 22. The plurality of first organic layers 22 are stacked along the thickness direction of the main portion 21. A wiring board 1 having such a main portion 21 has a high degree of freedom in design. In the example shown in FIG. 1 , the main portion 21 has six first organic layers 22, but the number of first organic layers 22 is not limited to six. The number of first organic layers 22 may be two to five, or may be seven or more.

[0031] First organic substrate 20 may include third surface layer 251. Third surface layer 251 is an organic layer having third surface 103. In other words, third surface layer 251 is a bonding layer 25 that is bonded to inorganic substrate 10.

[0032] The first organic base material 20 may have a reinforcing layer 23 that is a core layer. The reinforcing layer 23 is mainly composed of a fourth organic component. The fourth organic component may be an organic resin. The organic resin may be, for example, an epoxy resin, a polyimide resin, an acrylic resin, a polycarbonate resin, an olefin resin, or a polyphenylene resin.

[0033] The organic resin may be, for example, polytetrafluoroethylene (PTFE), other fluororesins, or polyphenylene ether resin. The reinforcing layer 23 may contain glass cloth in which glass fibers, which are glass processed into fibrous form, are mixed into the organic resin.

[0034] The reinforcing layer 23 has a ninth side 109 and a tenth side 120 located opposite the ninth side 109. The ninth side 109 is bonded to an eleventh side 121 of the first organic substrate 20. The tenth side 120 is bonded to a twelfth side 122 of the first organic substrate 20. In this manner, the reinforcing layer 23 is located between predetermined first organic layers 22 of the first organic substrate 20.

[0035] When the reinforcing layer 23 contains glass cloth, the reinforcing layer 23 has higher rigidity than the first organic layer 22, which is the other portion of the main portion 21. This improves the rigidity of the first organic base material 20. Therefore, according to the wiring board 1 of this embodiment, warping or deflection of the first organic base material 20 can be suppressed when the first organic base material 20 is bonded to the inorganic base material 10.

[0036] <Second organic base material> The second organic base material 30 is mainly composed of a second organic component. The second organic base material 30 has a higher thermal expansion coefficient than the inorganic base material 10. The second organic component may be an organic resin. The organic resin may be, for example, a thermosetting resin such as an epoxy resin, a polyimide resin, an acrylic resin, or an olefin resin. The organic resin may be a polycarbonate resin, a polyphenylene resin, or the like.

[0037] The organic resin may be, for example, polytetrafluoroethylene (PTFE) or other fluororesin or polyphenylene ether resin. The second organic base material 30 may contain components other than the organic resin.

[0038] The second organic base material 30, which is mainly composed of the second organic component, is easier to form a fine wiring pattern on than the inorganic base material 10. On the other hand, the inorganic base material 10 made of ceramic has higher rigidity than the second organic base material 30. The inorganic base material 10 may have a higher density than the second organic base material 30.

[0039] The second organic base material 30 has a seventh surface 107 and an eighth surface 108 located opposite the seventh surface 107. The second organic base material 30 may be a plate-like body having the seventh surface 107 and the eighth surface 108 as main surfaces.

[0040] The second organic base material 30 is bonded to the second surface 102 of the inorganic base material 10. The second organic base material 30 located on the second surface 102 of the inorganic base material 10 may be bonded to the motherboard 2 at a bonding portion 62 which is wiring on the eighth surface 108.

[0041] 1, the second organic base material 30 has one second organic layer 31, but the number of second organic layers 31 is not limited to one. The number of second organic layers 31 may be multiple. The multiple second organic layers 31 are stacked along the thickness direction of the second organic base material 30.

[0042] Second organic substrate 30 includes fourth surface 311. Fourth surface 311 is an organic layer having seventh surface 107. In other words, third surface 251 is bonding layer 27 bonded to inorganic substrate 10.

[0043] In the wiring board 1 according to the embodiment, the thermal expansion coefficient of the first organic base material 20 is greater than that of the inorganic base material 10, and the thermal expansion coefficient of the second organic base material 30 is greater than that of the inorganic base material 10. This allows the thermal expansion coefficients of the first organic base material 20 on the first surface 101 of the inorganic base material 10 and the second organic base material 30 on the second surface 102 to be balanced. Therefore, the wiring board 1 according to the present embodiment can reduce warping of the wiring board 1 caused by expansion or contraction of one surface of the inorganic base material 10. Furthermore, a semiconductor element 3 can be mounted on the wiring board 1 with reduced warping due to the difference in thermal expansion coefficients.

[0044] Furthermore, when a thermosetting resin is used for bonding layers 25, 27, the inorganic base material 10 and the organic base material are bonded together at a high temperature and then cooled to room temperature, which may cause the organic base material to remain in a contracted state during use of wiring board 1, resulting in a concern that warping may become more pronounced. According to wiring board 1 of the present embodiment, it is possible to reduce the occurrence of warping when a thermosetting resin is used for bonding layer 25 that bonds inorganic base material 10 and first organic base material 20. It is also possible to reduce the occurrence of warping when a thermosetting resin is used for bonding layer 27 that bonds inorganic base material 10 and second organic base material 30.

[0045] Furthermore, the second organic base material 30 has a coefficient of thermal expansion closer to that of the motherboard 2 than the inorganic base material 10. Therefore, according to the wiring board 1 of this embodiment, the difference in the coefficient of thermal expansion between the second organic base material 30 and the motherboard 2 can be reduced.

[0046] Furthermore, the wiring board 1 can achieve finer wiring and narrower pitches while increasing rigidity by combining the inorganic base material 10 and the first organic base material 20. Since warping of the substrate becomes more pronounced as the substrate becomes larger, the configuration of the wiring board 1 in which the inorganic base material 10 compensates for the low rigidity of the first organic base material 20 is particularly useful for increasing the size of the substrate.

[0047] The inorganic base material 10 and the bonding layers 25, 27 are bonded together by, for example, hydrogen bonding. Specifically, the inorganic base material 10 and the bonding layers 25, 27 are bonded together by bonding between hydroxyl groups of the inorganic base material 10 and the bonding layers 25, 27. In this case, a ceramic material such as alumina having surface hydroxyl groups may be used for the inorganic base material 10, and an epoxy resin, which is a resin material containing hydroxyl groups, may be used for the bonding layers 25, 27. In this way, by directly bonding the inorganic base material 10 and the bonding layers 25, 27 without using solder, underfill, or the like, the thickness of the wiring board 1 can be reduced.

[0048] Next, the configuration of the first wiring 32 to the fifth wiring 60 provided in the wiring board 1 will be described with reference to FIGS. 1 to 5. FIG. 2 is a schematic cross-sectional view showing the configuration of the first organic base material 20 side of the wiring board 1 according to the embodiment. FIG. 3 is a schematic cross-sectional view showing the configuration of the second organic base material 30 side of the wiring board 1 according to the embodiment. FIG. 4 is an enlarged cross-sectional view showing an example of the configuration of the H1 portion shown in FIG. 1. FIG. 5 is an enlarged cross-sectional view showing an example of the configuration of the H2 portion shown in FIG. 1.

[0049] <1st wiring> 1, the first wiring 32 is located inside the inorganic base material 10, and extends from the first surface 101 to the second surface 102. Note that "extending" here does not necessarily mean extending over the shortest distance.

[0050] The first wiring 32 may include a plurality of first via conductors 33, a plurality of fourth via conductors 34, a plurality of sixth via conductors 35, and a plurality of first wiring layers 36. The first via conductors 33 penetrate the first surface layer 111. The fourth via conductor 34 penetrates the second surface layer 112. The sixth via conductor 35 penetrates the inner layer 113. The first wiring layer 36 is located between adjacent inorganic layers 11, and electrically connects the first via conductors 33 and the sixth via conductor 35, and the fourth via conductor 34 and the sixth via conductor 35.

[0051] In this way, the wiring board 1 has the first wiring 32 including the multiple first wiring layers 36 inside the inorganic base material 10, and therefore has a higher degree of freedom in wiring design compared to conventional wiring boards 1 that have wiring only in an organic resin substrate. On the other hand, when a configuration is adopted in which wiring is provided in both the inorganic base material 10 and the first organic base material 20, in this case the first wiring 32 and the second wiring 40, it is desirable to bond the inorganic base material 10 and the first organic base material 20 more firmly so that misalignment between the first wiring 32 and the second wiring 40 does not occur.

[0052] The first wiring 32 may have a first land 37 on the first surface 101 of the inorganic base material 10. The first wiring 32 may have a third land 38 on the second surface 102 of the inorganic base material 10. In the first wiring 32, the first via conductor 33, the fourth via conductor 34, the sixth via conductor 35, the first wiring layer 36, the first land 37, and the third land 38 may be electrically connected to each other.

[0053] <Second wiring> 1 and 2, the second wiring 40 is located on the first organic base material 20, and extends from the fifth surface 105 to the sixth surface 106. Note that "extending" here does not necessarily mean extending the shortest distance.

[0054] The second wiring 40 has a plurality of second via conductors 41 and one or more second wiring layers 42. The second via conductors 41 and the second wiring layer 42 are located inside the first organic base material 20. The second via conductors 41 penetrate one or more first organic layers 22. When there are multiple first organic layers 22, the second wiring layer 42 is located, for example, between adjacent first organic layers 22, and electrically connects the multiple second via conductors 41 together.

[0055] The second wiring 40 also has a second land 43, which is a bonding conductor, located on the fifth surface 105, which is the surface of the first organic base material 20. The second land 43 may be a conductor containing a silica component. The second land 43 is located between the first organic base material 20 and the bonding layer 25, and electrically connects the first organic base material 20 and the bonding layer 25. A wiring board 1 having such a second land 43 has a high degree of freedom in design.

[0056] The second land 43 may contain hydroxyl groups on the surface. The second land 43 may be chemically bonded to the main portion 21 by the hydroxyl groups, and the hydroxyl groups are hydrogen-bonded to the main portion 21. This allows the second land 43 to be firmly bonded to the main portion 21. The second land 43 may also be chemically bonded to the bonding layer 25 by the hydroxyl groups, and the hydroxyl groups are hydrogen-bonded to the bonding layer 25. This allows the second land 43 to be firmly bonded to the bonding layer 25.

[0057] The first wiring 32 and the second wiring 40 may be, for example, a metal conductor whose main component is copper or silver. For example, the first wiring 32 and the second wiring 40 may both be metal conductors whose main component is copper. Alternatively, the first wiring 32 and the second wiring 40 may both be metal conductors whose main component is silver. Alternatively, one of the first wiring 32 and the second wiring 40 may be a metal conductor whose main component is copper, and the other may be a metal conductor whose main component is silver.

[0058] By making all of the first wiring 32 and the second wiring 40 metal conductors whose main component is copper or silver, it is possible to obtain higher electrical characteristics than when, for example, one of the first wiring 32 and the second wiring 40 is made of a metal conductor other than copper or silver.

[0059] Of the first wiring 32 and the second wiring 40, only the first wiring 32 may contain a glass component. In this case, the first wiring 32 is firmly bonded to the inorganic base material 10, which also contains a glass component, via the glass component. This allows the rigidity of the inorganic base material 10 to be increased.

[0060] The second wiring 40 may be electrically and thermally connected to the semiconductor element 3. By thermally connecting the second wiring 40, which is mainly composed of copper or silver, which has a relatively high thermal conductivity, to the semiconductor element 3, which serves as a heat source, the heat generated from the semiconductor element 3 can be efficiently dissipated via the second wiring 40 and the first wiring 32.

[0061] <3rd wiring> As shown in FIG. 2 , the third wiring 50 is located on the bonding layer 25 and extends from the third surface 103 to the fourth surface 104. Note that "extending" here does not necessarily mean extending the shortest distance. The third wiring 50 is electrically bonded to the first wiring 32 at the bonding surface with the inorganic base material 10. The third wiring 50 is electrically bonded to the second wiring 40 at the bonding surface with the first organic base material 20. The third wiring 50 may have a wiring layer in the middle that forms the portion extending along the third surface 103 and the fourth surface 104.

[0062] The third wiring 50 has a third via conductor 51. The third via conductor 51 is located inside the bonding layer 25, which is the third surface layer 251, and penetrates the bonding layer 25. The third via conductor 51 connects between the first land 37 and the second land 43. In this manner, the third via conductor 51 electrically connects the first wiring 32 and the second wiring 40. The third via conductor 51 may be a conductor whose main component is copper or a metal other than copper, such as silver.

[0063] The third via conductor 51 may have an alloy layer (not shown) at the interface with the first land 37. When the third via conductor 51 has an alloy layer at the interface with the first land 37, the alloy layer can increase the bonding strength between the first land 37 and the third via conductor 51. This can increase the connection reliability between the first wiring 32 and the third wiring 50.

[0064] <Land 1 and Land 2> 2 , in the wiring board 1, at least a portion of the first land 37 may extend into the bonding layer 25. At least a portion of the first land 37 in the thickness direction may extend into the bonding layer 25. The entire first land 37 in the thickness direction may extend into the bonding layer 25.

[0065] At least a portion of the first land 37 located on the first surface 101 of the inorganic base material 10 penetrates into the bonding layer 25, thereby suppressing expansion or contraction in the X-axis direction shown in FIG. 1 , which is the direction along the third surface 103 or the fourth surface 104 of the bonding layer 25. This reduces the load on the interface between the inorganic base material 10 and the bonding layer 25, thereby improving the bonding reliability of the base material. Furthermore, at least a portion of the first land 37 penetrates into the bonding layer 25, thereby reducing the thickness of the wiring board 1. This allows the wiring board 1 to be made smaller.

[0066] Furthermore, in the wiring board 1, at least a portion of the second land 43 may extend into the bonding layer 25. At least a portion of the second land 43 in the thickness direction may extend into the bonding layer 25. The entire second land 43 in the thickness direction may extend into the bonding layer 25.

[0067] At least a portion of second land 43 located on fifth surface 105 of main portion 21 penetrates into bonding layer 25, thereby suppressing expansion or contraction of bonding layer 25 in the X-axis direction. This reduces the load on the interface between main portion 21 and bonding layer 25, thereby improving the bonding reliability of the base material. Furthermore, at least a portion of second land 43 penetrates into bonding layer 25, thereby reducing the thickness of wiring board 1. This allows wiring board 1 to be made smaller.

[0068] <5th wiring> 3, the fifth wiring 60 is located in the second organic layer 31 and extends from the seventh surface 107 to the eighth surface 108. Note that "extending" here does not necessarily mean extending over the shortest distance. The fifth wiring 60 is electrically connected to the first wiring 32 at the bonding surface with the inorganic base material 10. The fifth wiring 60 may have a wiring layer in the middle that forms the portion that extends along the seventh surface 107 or the eighth surface 108.

[0069] The fifth wiring 60 has a fifth via conductor 61. The fifth via conductor 61 is located inside the bonding layer 27, which is the fourth surface layer 311, and penetrates the bonding layer 27. The fifth via conductor 61 connects between the third land 38 and the bonding portion 62. In this way, the fifth via conductor 61 can electrically connect the first wiring 32 and the motherboard 2. The fifth via conductor 61 may be a conductor whose main component is copper or a metal other than copper, such as silver.

[0070] <Regarding the inclination of the via conductor of the first wiring and the fifth via conductor> Next, specific configurations of the first via conductor 33 and the fourth via conductor 34 of the first wiring 32 and the fifth via conductor 61 will be described with reference to Fig. 3. Note that the fourth wiring 45 in the following description is composed of the second wiring 40 and the fifth wiring 60 described above.

[0071] 3 , in the wiring board 1 according to the embodiment, the first via conductors 33 may be inclined with respect to the thickness direction of the inorganic base material 10, in other words, with respect to the stacking direction of the multiple inorganic layers 11. Specifically, the inclination angle of the first via conductors 33 with respect to the thickness direction of the inorganic base material 10 may be larger than the inclination angle of the third via conductors 51 with respect to the thickness direction of the inorganic base material 10.

[0072] When the temperature of the wiring board 1 increases, the first via conductors 33 thermally expand, and the thermally expanded first via conductors 33 push up the first organic base material 20, which may cause the first organic base material 20 to easily peel off from the inorganic base material 10. Furthermore, when the thermally expanded first via conductors 33 push up the first organic base material 20, electrical conduction between the first wiring 32 located on the inorganic base material 10 and the fourth wiring 45 located on the first organic base material 20 may become insufficient.

[0073] In contrast, in the wiring board 1 according to the embodiment, the first via conductors 33 located on the first surface layer 111 of the inorganic base material 10 may be inclined with respect to the thickness direction of the inorganic base material 10. When thermally expanded, such first via conductors 33 extend not only in the thickness direction of the inorganic base material 10 but also in an in-plane direction perpendicular to the thickness direction. Therefore, the first via conductors 33 according to the embodiment extend less in the thickness direction of the inorganic base material 10 when thermally expanded than via conductors that extend straight toward the first organic base material 20. That is, the first via conductors 33 according to the embodiment are less likely to push up against the first organic base material 20 when thermally expanded than via conductors that extend straight toward the first organic base material 20.

[0074] Therefore, in the wiring board 1 according to the embodiment, even if the first via conductors 33 thermally expand, the first organic base material 20 is unlikely to peel off from the inorganic base material 10. Furthermore, electrical conduction between the first wiring 32 located on the inorganic base material 10 and the fourth wiring 45 located on the first organic base material 20 is unlikely to become insufficient.

[0075] Thus, according to the wiring board 1 of the embodiment, even if the first via conductor 33 undergoes thermal expansion, the dimensional change of the first via conductor 33 is unlikely to affect the first organic base material 20, resulting in high bonding reliability between the inorganic base material 10 and the first organic base material 20.

[0076] The first via conductor 33 may be inclined in the opposite direction to the inclination direction shown in Fig. 3. In other words, the first via conductor 33 may be inclined so that the end on the first organic base material 20 side is located closer to the center of the inorganic base material 10 than the other end.

[0077] 3, the inclination angle of first via conductors 33 located in the central portion of first surface layer 111 may be smaller than the inclination angle of first via conductors 33 located in the outer periphery of first surface layer 111. In other words, the multiple first via conductors 33 may be arranged such that the inclination angle increases from the central portion of first surface layer 111 toward the outer periphery of first surface layer 111.

[0078] In the wiring board 1 according to the embodiment, the fourth via conductor 34 may be inclined with respect to the thickness direction of the inorganic base material 10, in other words, with respect to the stacking direction of the multiple inorganic layers 11. Specifically, the inclination angle of the fourth via conductor 34 with respect to the thickness direction of the inorganic base material 10 may be larger than the inclination angle of the fifth via conductor 61 with respect to the thickness direction of the inorganic base material 10.

[0079] As a result, in the wiring board 1 of the embodiment, when other components such as a motherboard 2 are attached to the second surface layer 112 via the second organic layer 31, the effects of changes in the dimensions of the fourth via conductor 34 due to thermal expansion can be reduced.

[0080] Furthermore, the fifth via conductor 61 may contain at least one of an organic component and Sn (tin). This allows the fifth via conductor 61 to have a higher thermal expansion coefficient than when it is made of only copper. In this case, the difference between the thermal expansion coefficient of the entire wiring board 1 and the thermal expansion coefficient of the motherboard 2 can be reduced.

[0081] <Convex body> 4, the wiring substrate 1 may have a plurality of convex bodies 4. The plurality of convex bodies 4 protrude from the first surface 101 of the inorganic base material 10 toward the first organic base material 20, and may extend into the first organic base material 20.

[0082] As shown in FIG. 5, the plurality of protrusions 4 protrude from the second surface 102 of the inorganic substrate 10 toward the second organic substrate 30 , and may extend into the interior of the second organic substrate 30 .

[0083] The wiring substrate 1 having the above configuration can increase the bonding strength between the inorganic base material 10 and the first organic base material 20 and the second organic base material 30 due to the anchor effect caused by the multiple convex bodies 4 penetrating into the first organic base material 20 and the second organic base material 30.

[0084] Next, the wiring pitch of the wiring substrate 1, the horizontal width L1 of the inorganic base material 10, and the horizontal width L2 of the first organic base material 20 will be described with reference to Fig. 6. Fig. 6 is a schematic cross-sectional view illustrating the wiring pitch, the horizontal width L1 of the inorganic base material 10, and the horizontal width L2 of the first organic base material 20.

[0085] As shown in FIG. 6 , the wiring pitch on the eighth surface 108, which is the outer surface of the second organic base material 30, may be larger than the wiring pitch on the sixth surface 106, which is the outer surface of the first organic base material 20. As indicated by the arrows in FIG. 6 , the wiring arrangement may have a narrower pitch on each base material from the motherboard 2 side toward the semiconductor element 3 side. In other words, in the wiring board 1, the wiring pitch may be gradually narrower from the motherboard 2 side toward the semiconductor element 3 side. This reduces the wiring pitch from the second organic base material 30 to the first organic base material 20. Therefore, in the wiring board 1, for example, the semiconductor element 3 can be connected to the first wiring 32 on the sixth surface 106 of the first organic base material 20, and the motherboard 2 can be connected to the third wiring 50 on the eighth surface 108 of the second organic base material 30.

[0086] Furthermore, the horizontal width L1 of the inorganic base material 10 may be larger than the horizontal width L2 of the first organic base material 20. In the wiring board 1, a region A1 to which the first organic layer 22 is not bonded is located on the first surface 101 of the inorganic base material 10. According to the wiring board 1 of the present embodiment, the heat dissipation properties of the wiring board 1 can be improved by locating the region A1 on the first surface 101 of the inorganic base material 10.

[0087] 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.

[0088] The disclosed embodiments should be considered to be illustrative in all respects and not restrictive. Indeed, the above-described embodiments can be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. Combinations of embodiments are also possible.

[0089] The present technology can also be configured as follows. (1) an inorganic substrate including a plurality of inorganic layers primarily composed of low-temperature co-fired ceramic; a first wiring layer located between two adjacent inorganic layers; a first organic substrate including a plurality of first organic layers mainly composed of an organic component and bonded to a first surface of the inorganic substrate; a second organic substrate that is mainly composed of an organic component and is bonded to a second surface of the inorganic substrate that is located opposite the first surface; Equipped with The thermal expansion coefficient of the first organic base material is greater than the thermal expansion coefficient of the inorganic base material, and the thermal expansion coefficient of the second organic base material is greater than the thermal expansion coefficient of the inorganic base material. Wiring board. (2) Among the plurality of first organic layers, at least the first organic layer bonded to the first surface is made of a thermosetting resin. The wiring board according to (1). (3) The second organic base material is a thermosetting resin. The wiring board according to (1) or (2). (4) the first organic base material includes a main portion including the plurality of first organic layers and a bonding layer located between the main portion and the inorganic base material; the bonding layer has a third surface bonded to the first surface and a fourth surface located opposite the third surface, the main portion has a fifth surface joined to the fourth surface and a sixth surface located opposite the fifth surface, a first wiring located inside the inorganic base material and extending from the first surface to the second surface; a second wiring located inside the main portion and extending from the fifth surface to the sixth surface; a third wiring located inside the bonding layer and extending from the third surface to the fourth surface, the first wiring has a first via conductor and a first land located on the first surface and electrically connected to the first via conductor; the second wiring has a second via conductor and a second land located on the fifth surface and electrically connected to the second via conductor; the third wiring has a third via conductor connecting between the first land and the second land, At least a portion of the first land and the second land extends into the bonding layer. The wiring board according to any one of (1) to (3). (5) the first organic base material has a third surface bonded to the first surface and a sixth surface located opposite the third surface; the second organic base material has a seventh surface bonded to the second surface and an eighth surface located opposite the seventh surface; the plurality of inorganic layers include a first surface layer having the first surface and a second surface layer having the second surface, the plurality of first organic layers include a third surface layer having the third surface, the second organic substrate includes one or more second organic layers including a fourth surface layer having the seventh surface; a first wiring located inside the inorganic base material and extending from the first surface to the second surface; a fourth wiring located inside the first organic base material and extending from the third surface to the sixth surface; a fifth wiring located inside the second organic base material and extending from the seventh surface to the eighth surface; and and the first wiring has a first via conductor penetrating the first surface layer and a fourth via conductor penetrating the second surface layer; the fourth wiring has a third via conductor penetrating the third surface layer, the fifth wiring has a fifth via conductor penetrating the fourth surface layer, an inclination angle of the first via conductor with respect to the thickness direction of the inorganic base material is larger than an inclination angle of the third via conductor with respect to the thickness direction of the inorganic base material; The inclination angle of the fourth via conductor with respect to the thickness direction of the inorganic base material is larger than the inclination angle of the fifth via conductor with respect to the thickness direction of the inorganic base material. The wiring board according to any one of (1) to (4). (6) a plurality of convex portions protruding from the first surface and extending into the first organic base material; a plurality of convex bodies protruding from the second surface and extending into the second organic base material; and The convex body contains a glass component and is bonded to the inorganic substrate by the glass component. The wiring board according to any one of (1) to (5). (7) The first organic substrate has a core layer containing glass cloth. The wiring board according to any one of (1) to (6). (8) the second organic base material has a fifth via conductor penetrating the second organic base material; The fifth via conductor includes at least one of an organic component and Sn (tin). The wiring board according to any one of (1) to (7). (9) The wiring pitch on the outer surface of the second organic base material is larger than the wiring pitch on the outer surface of the first organic base material. The wiring board according to any one of (1) to (8). (10) A motherboard is attached to the second organic base material via wiring on the outer surface of the second organic base material. The wiring board according to any one of (1) to (9). (11) A wiring board according to any one of (1) to (10), a semiconductor element mounted on the wiring board; Equipped with Semiconductor devices. [Explanation of symbols]

[0090] 1. Wiring board 2 Motherboard 3. Semiconductor elements 4 Convex body 10 Inorganic substrate 11 Inorganic layer 20 First organic base material 21 Main Section 22 1st organic layer 23 Reinforcement layer 25 Bonding layer 27 Bonding layer 30 Second organic base material 31 2nd organic layer 32 1st wiring 33 First via conductor 34 4th via conductor 35 6th via conductor 36 1st wiring layer 37 Land 1 38 Third Land 40 2nd wiring 41 Second via conductor 42 2nd wiring layer 43 Second Land 45 4th wiring 50 3rd wiring 51 Third via conductor 60 5th wiring 61 5th via conductor 62 Joint 101 Page 1 102 Side 2 103 3rd page 104 Page 4 105 Page 5 106 Page 6 107 Page 7 108 Page 8 109 Page 9 110 Page 10 111 1st surface layer 112 2nd surface layer 113 Inner layer 121 Page 11 122 Page 12 251 Third surface layer 311 4th surface layer A1 area

Claims

1. an inorganic substrate including a plurality of inorganic layers primarily composed of low-temperature co-fired ceramic; a first wiring layer located between two adjacent inorganic layers; a first organic substrate including a plurality of first organic layers mainly composed of an organic component and bonded to a first surface of the inorganic substrate; a second organic substrate that is mainly composed of an organic component and is bonded to a second surface of the inorganic substrate that is located opposite the first surface; and Equipped with The thermal expansion coefficient of the first organic base material is greater than the thermal expansion coefficient of the inorganic base material, and the thermal expansion coefficient of the second organic base material is greater than the thermal expansion coefficient of the inorganic base material. Wiring board.

2. Among the plurality of first organic layers, at least the first organic layer bonded to the first surface is made of a thermosetting resin. The wiring board according to claim 1 .

3. The second organic base material is a thermosetting resin. The wiring board according to claim 1 .

4. the first organic base material includes a main portion including the plurality of first organic layers and a bonding layer located between the main portion and the inorganic base material; the bonding layer has a third surface bonded to the first surface and a fourth surface located opposite the third surface; the main portion has a fifth surface joined to the fourth surface and a sixth surface located opposite the fifth surface, a first wiring located inside the inorganic base material and extending from the first surface to the second surface; a second wiring located inside the main portion and extending from the fifth surface to the sixth surface; a third wiring located inside the bonding layer and extending from the third surface to the fourth surface; the first wiring has a first via conductor and a first land located on the first surface and electrically connected to the first via conductor; the second wiring has a second via conductor and a second land located on the fifth surface and electrically connected to the second via conductor; the third wiring has a third via conductor connecting the first land and the second land, At least a portion of the first land and the second land extends into the bonding layer. The wiring board according to claim 1 .

5. the first organic base material has a third surface bonded to the first surface and a sixth surface located opposite the third surface; the second organic base material has a seventh surface bonded to the second surface and an eighth surface located opposite the seventh surface; the plurality of inorganic layers include a first surface layer having the first surface and a second surface layer having the second surface, the plurality of first organic layers include a third surface layer having the third surface, the second organic substrate includes one or more second organic layers including a fourth surface layer having the seventh surface; a first wiring located inside the inorganic base material and extending from the first surface to the second surface; a fourth wiring located inside the first organic base material and extending from the third surface to the sixth surface; a fifth wiring located inside the second organic base material and extending from the seventh surface to the eighth surface; and and the first wiring has a first via conductor penetrating the first surface layer and a fourth via conductor penetrating the second surface layer; the fourth wiring has a third via conductor penetrating the third surface layer, the fifth wiring has a fifth via conductor penetrating the fourth surface layer, an inclination angle of the first via conductor with respect to the thickness direction of the inorganic base material is larger than an inclination angle of the third via conductor with respect to the thickness direction of the inorganic base material; The inclination angle of the fourth via conductor with respect to the thickness direction of the inorganic base material is larger than the inclination angle of the fifth via conductor with respect to the thickness direction of the inorganic base material. The wiring board according to claim 1 .

6. a plurality of convex portions protruding from the first surface and extending into the first organic base material; a plurality of convex bodies protruding from the second surface and extending into the second organic base material; and The convex body contains a glass component and is bonded to the inorganic substrate by the glass component. The wiring board according to claim 1 .

7. The first organic substrate has a core layer containing glass cloth. The wiring board according to claim 1 .

8. the second organic base material has a fifth via conductor penetrating the second organic base material; The fifth via conductor contains at least one of an organic component and Sn (tin). The wiring board according to claim 1 .

9. The wiring pitch on the outer surface of the second organic base material is larger than the wiring pitch on the outer surface of the first organic base material. The wiring board according to claim 1 .

10. A motherboard is attached to the second organic base material via wiring on the outer surface of the second organic base material. The wiring board according to claim 1 .

11. A wiring board according to any one of claims 1 to 10; a semiconductor element mounted on the wiring board; Equipped with Semiconductor devices.

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