Wiring board and semiconductor device

Abstract

This wiring board comprises an inorganic base material, a conductor, a first organic base material, a second organic base material, and a bonding layer. The inorganic base material contains ceramic as a main component. The conductor is positioned inside a through-hole that penetrates the inorganic base material. The first organic base material includes a plurality of first organic layers containing an organic component and is bonded to a first surface of the inorganic base material. The second organic base material contains an organic component and is bonded to a second surface that is positioned on the opposite side from the first surface of the inorganic base material. A bonding layer is positioned between the first organic base material and the inorganic base material, and between the second organic base material and the inorganic base material. In the wiring board, the coefficient of thermal expansion of the first organic base material is greater than the coefficient of thermal expansion of the inorganic base material, and the coefficient of thermal expansion of the second organic base material is greater than the coefficient of thermal expansion of the inorganic base material.

Description

Wiring board and semiconductor device

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

[0002] A wiring board is known in which an organic base material including a wiring layer is laminated on a ceramic base material as a core layer (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2015-179816

[0004] The wiring board of the present disclosure includes an inorganic base material, a conductor, a first organic base material, a second organic base material, and a bonding layer. The inorganic base material is primarily composed of ceramic. The conductor is located inside a through hole penetrating the inorganic base material. The first organic base material includes a plurality of first organic layers containing an organic component and is bonded to a first surface of the inorganic base material. The second organic base material contains an organic component and is bonded to a second surface of the inorganic base material located opposite the first surface. The bonding layers are located between the first organic base material and the inorganic base material, and between the second organic base material and the inorganic base material. In the wiring board, 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.

[0005] Fig. 1 is a schematic cross-sectional view showing the configuration of a wiring substrate according to an embodiment. Fig. 2 is a schematic cross-sectional view showing the configuration of a first organic base material side of a wiring substrate according to an embodiment. Fig. 3 is a schematic cross-sectional view showing the configuration of a second organic base material side of a wiring substrate according to an embodiment. Fig. 4 is a schematic cross-sectional view illustrating a wiring pitch, a horizontal width of an inorganic base material, and a horizontal width of a first organic base material.

[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] 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.

[0008] In addition, in the drawings referred to below, for ease of understanding, 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 positive Z-axis direction is the vertically upward direction.

[0009] In the above-described wiring board, there is a concern that the wiring board may warp due to the difference in thermal expansion coefficient between the organic layer and the ceramic base material.

[0010] The present disclosure provides a technique that can reduce warpage of a wiring board due to differences in thermal expansion coefficients.

[0011] 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.

[0012] 1 , the wiring substrate 1 includes 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.

[0013] <Inorganic Substrate> The inorganic substrate 10 is a substrate primarily composed of 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 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 the glass phase, and a form 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.

[0014] For example, the inorganic substrate 10 may be made of low temperature co-fired ceramics (LTCC). When LTCC is used as the inorganic substrate 10, the inorganic substrate 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 the wiring. In this embodiment, the low-melting-point metal is a metal with a melting point lower than that of typical metals used for wiring in ceramic substrates, such as tungsten or molybdenum.

[0015] 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.

[0016] 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. The inorganic substrate 10 has first through holes 12 that penetrate from the first surface 101 to the second surface 102.

[0017] In an embodiment, the inorganic substrate 10 may have one ceramic layer 11. In the example shown in Fig. 1 , the inorganic substrate 10 has one ceramic layer 11, but the number of ceramic layers 11 is not limited to one. The number of ceramic layers 11 may be multiple.

[0018] When the number of ceramic layers 11 is multiple, the multiple ceramic layers 11 are stacked along the thickness direction of the inorganic substrate 10. A wiring board 1 having such an inorganic substrate 10 offers a high degree of design freedom. Furthermore, by constructing the inorganic substrate 10 using multiple ceramic layers 11, the inorganic substrate 10 can be manufactured while checking whether the first conductors 35 are properly formed for each layer, thereby improving the yield of the inorganic substrate 10. Furthermore, by constructing the inorganic substrate 10 using multiple ceramic layers 11, interlayer wiring can be arranged between adjacent ceramic layers 11. The interlayer wiring may be, for example, a power supply wiring or a ground wiring. In this embodiment, the inorganic substrate 10 may have interlayer wiring in addition to the first conductors 35.

[0019] In the wiring board 1, the inorganic base material 10 may incorporate components (not shown) to be mounted on the wiring board 1. Components that may be incorporated in the inorganic base material 10 include capacitors and other chip components. Since the components are incorporated in the inorganic base material 10, it is possible to miniaturize a semiconductor device that uses the wiring board 1.

[0020] <First Organic Base Material and Bonding Layer> The first organic base material 20 contains a first organic component. The first organic base material 20 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.

[0021] The organic resin may be, for example, polytetrafluoroethylene (PTFE) or other fluororesins or polyphenylene ether resins. The first organic base material 20 may contain components other than the organic resin. In the present disclosure, the first organic base material 20 may contain the organic resin as a material that accounts for, for example, 30% by volume or more of the material.

[0022] The first organic base material 20 containing the first organic component is more likely to form a fine wiring pattern than the inorganic base material. On the other hand, the ceramic inorganic base material 10 has higher rigidity than the first organic base material 20. The inorganic base material 10 may have a higher density than the first organic base material 20.

[0023] The first organic base material 20 has a fifth surface 105 and a sixth surface 106 located opposite the fifth surface 105. The first organic base material 20 may be a plate-like body having the fifth surface 105 and the sixth surface 106 as main surfaces.

[0024] The bonding layer 25 is a layer located between the inorganic substrate 10 and the first organic substrate 20 and bonds to the inorganic substrate 10 and the first organic substrate 20, respectively. The bonding layer 25 includes a third organic component. The bonding layer 25 has a higher thermal expansion coefficient than the inorganic substrate 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 first organic substrate 20 described above.

[0025] 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.

[0026] The first organic base material 20 is bonded to the first surface 101 of the inorganic base material 10 via a bonding layer 25. The first organic base material 20, which is located on the first surface 101 of the inorganic base material 10 via the bonding layer 25, may have a semiconductor element 3 mounted on a sixth surface 106, and a fifth surface 105 of the first organic base material 20 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.

[0027] The first organic base material 20 may have a plurality of first organic layers 21. The plurality of first organic layers 21 are stacked along the thickness direction of the first organic base material 20. A wiring substrate 1 having such a first organic base material 20 has a high degree of freedom in design. In the example shown in FIG. 1 , the first organic base material 20 has six first organic layers 21, but the number of first organic layers 21 is not limited to six. The number of first organic layers 21 may be two to five, or may be seven or more.

[0028] The first organic base material 20 may have a reinforcing layer 22 that is a core layer. The reinforcing layer 22 contains 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.

[0029] The organic resin may be, for example, polytetrafluoroethylene (PTFE), other fluororesins, or polyphenylene ether resin. The reinforcing layer 22 may include glass cloth, which is the organic resin mixed with glass fiber, which is glass processed into a fibrous form. In the present disclosure, the reinforcing layer 22 may include the organic resin as a material that accounts for, for example, 30% by mass or more of the material.

[0030] The reinforcing layer 22 has an eleventh surface 111 and a twelfth surface 112 located opposite the eleventh surface 111. The eleventh surface 111 is bonded to a thirteenth surface 113 of the first organic base material 20. The twelfth surface 112 is bonded to a fourteenth surface 114 of the first organic base material 20. In this manner, the reinforcing layer 22 is located between predetermined first organic layers 21 of the first organic base material 20.

[0031] When the reinforcing layer 22 contains glass cloth, the reinforcing layer 22 has higher rigidity than the first organic layer 21, which is the other portion of the first organic base material 20. 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.

[0032] <Second Organic Base Material and Bonding Layer> The second organic base material 30 contains 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, 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) or other fluororesins or polyphenylene ether resins. The second organic base material 30 may contain components other than the organic resin. In the present disclosure, the second organic base material 30 may contain, for example, an organic resin as a material that accounts for 30% by mass or more of the material.

[0034] The second organic base material 30 containing the second organic component is more likely to form a fine wiring pattern than the inorganic base material. On the other hand, the ceramic inorganic base material 10 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.

[0035] The second organic base material 30 has a ninth surface 109 and a tenth surface 110 located opposite the ninth surface 109. The second organic base material 30 may be a plate-like body having the ninth surface 109 and the tenth surface 110 as main surfaces.

[0036] The bonding layer 27 is a layer located between the inorganic substrate 10 and the second organic substrate 30 and bonds to the inorganic substrate 10 and the second organic substrate 30, respectively. The bonding layer 27 includes a fifth organic component. The bonding layer 27 has a higher thermal expansion coefficient than the inorganic substrate 10. The fifth 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. The organic resin contained in the bonding layer 27 may be the same as the organic resin contained in the second organic substrate 30 described above.

[0037] The bonding layer 27 may have a seventh surface 107 and an eighth surface 108 located opposite the seventh surface 107. The bonding layer 27 may be a plate-like body having the seventh surface 107 and the eighth surface 108 as main surfaces.

[0038] The second organic base material 30 is bonded to the second surface 102 of the inorganic base material 10 via the bonding layer 27. The second organic base material 30, which is located on the second surface 102 of the inorganic base material 10 via the bonding layer 27, may have wiring on its tenth surface 110 bonded to a motherboard (not shown), and the ninth surface 109 of the second organic base material 30 may be bonded to the eighth surface 108 of the bonding layer 27. The seventh surface 107 of the bonding layer 27 may be bonded to the second surface 102 of the inorganic base material 10.

[0039] The second organic base material 30 may have a plurality of second organic layers 31. The plurality of second organic layers 31 are stacked along the thickness direction of the second organic base material 30. A wiring board 1 having such a second organic base material 30 has a high degree of design freedom and is highly functional. In the example shown in FIG. 1 , the second organic base material 30 has six second organic layers 31, but the number of second organic layers 31 is not limited to six. The number of second organic layers 31 may be two to five, or may be seven or more.

[0040] The second organic base material 30 may have a reinforcing layer 32 that is a core layer. The reinforcing layer 32 contains a sixth organic component. The sixth 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.

[0041] The organic resin may be, for example, polytetrafluoroethylene (PTFE), other fluororesins, or polyphenylene ether resin. The reinforcing layer 32 may contain a component other than the organic resin. The reinforcing layer 32 may also contain glass cloth, which is the organic resin mixed with glass fiber, which is glass processed into a fibrous form. In the present disclosure, the reinforcing layer 32 may contain the organic resin as a material that accounts for, for example, 30% by mass or more of the material.

[0042] The reinforcing layer 32 has a fifteenth surface 115 and a sixteenth surface 116 located opposite the fifteenth surface 115. The fifteenth surface 115 is bonded to a seventeenth surface 117 of the second organic base material 30. The sixteenth surface 116 is bonded to an eighteenth surface 118 of the second organic base material 30. In this manner, the reinforcing layer 32 is located between predetermined second organic layers 31 of the second organic base material 30.

[0043] The reinforcing layer 32 is made of glass cloth and therefore has higher rigidity than the second organic layer 31, which is the other portion of the second organic base material 30. This improves the rigidity of the second organic base material 30. Therefore, according to the wiring board 1 of this embodiment, warping or deflection of the second organic base material 30 can be suppressed when the second organic base material 30 is bonded to the inorganic base material 10.

[0044] 1 shows an example in which the first organic base material 20 has the reinforcing layer 22, and the second organic base material 30 has the reinforcing layer 32. However, the wiring substrate 1 is not limited to this, and at least the second organic base material 30 may have the reinforcing layer 32.

[0045] 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 makes it possible to balance 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. Therefore, according to the wiring board 1 of the present embodiment, warping of the wiring board 1 caused by expansion or contraction of one surface of the inorganic base material 10 can be reduced.

[0046] Furthermore, when a thermosetting resin is used for the bonding layers 25, 27, the inorganic base material 10 and the organic base material are bonded at a high temperature and then cooled to room temperature, which may cause the organic base material to continue to shrink during use of the wiring board 1, potentially resulting in more pronounced warpage. According to the wiring board 1 of this embodiment, the occurrence of warpage can be reduced when a thermosetting resin is used for the bonding layer 25 that bonds the inorganic base material 10 and the first organic layer 21. Furthermore, the occurrence of warpage can be reduced when a thermosetting resin is used for the bonding layer 27 that bonds the inorganic base material 10 and the second organic base material 30.

[0047] Furthermore, the wiring substrate 1 can achieve finer wiring and narrower pitches while increasing rigidity by combining the inorganic base material 10 with the first organic base material 20 and the second organic base material 30. Since warping of the substrate becomes more pronounced as the substrate becomes larger, the configuration of the wiring substrate 1 in which the inorganic base material 10 compensates for the low rigidity of the first organic base material 20 and the second organic base material 30 is particularly useful for increasing the size of the substrate.

[0048] The inorganic base material 10 and the bonding layers 25, 27 are bonded together, for example, by 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.

[0049] Next, the configurations of the first conductor 35 and the first wiring 40 to fourth wiring 70 provided on the wiring substrate 1 will be described with reference to FIGS. 1 to 3. FIG. 2 is a schematic cross-sectional view showing the configuration of the first organic base material 20 side of the wiring substrate 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 substrate 1 according to the embodiment.

[0050] 1 , the first conductor 35 may have a through-hole via 36 located in the inorganic base material 10. The first conductor 35 may have a first land 37 on the first surface 101 of the inorganic base material 10. The first conductor 35 may have a third land 38 on the second surface 102 of the inorganic base material 10. In the first conductor 35, the through-hole via 36, ​​the first land 37, and the third land 38 are electrically connected to each other.

[0051] The first conductor 35 extends along the side surface of the first through hole 12. More specifically, in the first conductor 35, the through-hole via 36 may be located inside the first through hole 12 and extend along the side surface of the first through hole 12.

[0052] 1 and 2 , the first wiring 40 is located on the first organic base material 20 and extends from the fourth surface 104 to the sixth surface 106. Note that "extending" here does not necessarily mean extending the shortest distance.

[0053] The first wiring 40 has a plurality of first via conductors 41 and one or more first wiring layers 42. The first via conductors 41 and the first wiring layer 42 are located inside the first organic base material 20. The first via conductors 41 penetrate one or more first organic layers 21. When there are a plurality of ceramic layers 11, the first wiring layer 42 is located, for example, between adjacent first organic layers 21, and electrically connects the plurality of first via conductors 41 together.

[0054] The first 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.

[0055] The second land 43 may contain hydroxyl groups on the surface. The second land 43 may be chemically bonded to the first organic base material 20 by the hydroxyl groups, and the hydroxyl groups are hydrogen-bonded to the first organic base material 20. This allows the second land 43 to be firmly bonded to the first organic base material 20. 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.

[0056] The first conductor 35 and the first wiring 40 may be, for example, a metal conductor whose main component is copper or silver. For example, both the first conductor 35 and the first wiring 40 may be a metal conductor whose main component is copper. Alternatively, both the first conductor 35 and the first wiring 40 may be a metal conductor whose main component is silver. Alternatively, one of the first conductor 35 and the first 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.

[0057] By making all of the first conductor 35 and the first wiring 40 metal conductors whose main component is copper or silver, it is possible to obtain higher electrical characteristics compared to, for example, when one of the first conductor 35 and the first wiring 40 is made of a metal conductor other than copper or silver.

[0058] Of the first conductors 35 and the first wiring 40, only the first conductors 35 may contain a glass component. In this case, the first conductors 35 are 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.

[0059] The first wiring 40 may be electrically and thermally connected to the semiconductor element 3. By thermally connecting the first 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 first wiring 40 and the first conductor 35.

[0060] <Second Wiring> The second 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 over the shortest distance. The second wiring 50 is electrically bonded to the first conductor 35 at the bonding surface with the inorganic base material 10. The second wiring 50 is electrically bonded to the first wiring 40 at the bonding surface with the first organic base material 20. The second wiring 50 may have a wiring layer in the middle that forms the portion extending along the third surface 103 or the fourth surface 104.

[0061] The second wiring 50 has a third via conductor 51. The third via conductor 51 is located inside 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 conductor 35 and the first 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.

[0062] 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 40 and the second wiring 50.

[0063] 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.

[0064] 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. 2 , 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 substrate 1. This allows the wiring substrate 1 to be made smaller.

[0065] 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.

[0066] At least a portion of the second land 43 located on the fifth surface 105 of the first organic base material 20 penetrates into the bonding layer 25, thereby suppressing expansion or contraction of the bonding layer 25 in the X-axis direction. This reduces the load on the interface between the first organic base material 20 and the bonding layer 25, thereby improving the bonding reliability of the base material. Furthermore, at least a portion of the second land 43 penetrates into the bonding layer 25, thereby reducing the thickness of the wiring substrate 1. This allows the wiring substrate 1 to be miniaturized.

[0067] 1 and 3 , the third wiring 60 is located on the second organic base material 30, and extends from the ninth surface 109 to the tenth surface 110. Note that "extending" here does not necessarily mean extending the shortest distance.

[0068] The third wiring 60 has a plurality of second via conductors 61 and one or more second wiring layers 62. The second via conductors 61 and the second wiring layer 62 are located inside the second organic base material 30. The second via conductors 61 penetrate one or more second organic layers 31. When there are multiple second organic layers 31, the second wiring layer 62 is located, for example, between adjacent second organic layers 31, and electrically connects the multiple second via conductors 61 together.

[0069] The third wiring 60 also has a fourth land 63, which is a bonding conductor, located on the ninth surface 109, which is the surface of the second organic base material 30. The fourth land 63 may be a conductor containing a silica component. The fourth land 63 is located between the second organic base material 30 and the bonding layer 27, and electrically connects the second organic base material 30 and the bonding layer 27. A wiring board 1 having such a fourth land 63 has a high degree of freedom in design.

[0070] The fourth land 63 may contain hydroxyl groups on its surface. The fourth land 63 may be chemically bonded to the second organic base material 30 by the hydroxyl groups, and the hydroxyl groups are hydrogen-bonded to the second organic base material 30. This allows the fourth land 63 to be firmly bonded to the second organic base material 30. The fourth land 63 may also be chemically bonded to the bonding layer 27 by the hydroxyl groups, and the hydroxyl groups are hydrogen-bonded to the bonding layer 27. This allows the fourth land 63 to be firmly bonded to the bonding layer 27.

[0071] The third wiring 60 may be, for example, a metal conductor containing copper or silver as a main component. For example, one of the first conductor 35 and the third wiring 60 may be a metal conductor containing copper as a main component, and the other may be a metal conductor containing silver as a main component.

[0072] By making all of the first conductor 35 and the third wiring 60 metal conductors whose main component is copper or silver, it is possible to obtain higher electrical characteristics compared to, for example, when one of the first conductor 35 and the third wiring 60 is made of a metal conductor other than copper or silver.

[0073] <Fourth Wiring> The fourth wiring 70 is located on the bonding layer 27 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 fourth wiring 70 is electrically bonded to the first conductor 35 at the bonding surface with the inorganic base material 10. The fourth wiring 70 is electrically bonded to the third wiring 60 at the bonding surface with the second organic base material 30. The fourth wiring 70 may have a wiring layer in the middle that forms the portion that extends along the seventh surface 107 or the eighth surface 108.

[0074] The fourth wiring 70 has a fourth via conductor 71. The fourth via conductor 71 is located inside the bonding layer 27. The fourth via conductor 71 connects between the third land 38 and the fourth land 63. In this manner, the fourth via conductor 71 electrically connects the first conductor 35 and the third wiring 60. The fourth via conductor 71 may be a conductor whose main component is copper or a metal other than copper, such as silver.

[0075] The fourth via conductor 71 may have an alloy layer (not shown) at the interface with the third land 38. When the fourth via conductor 71 has an alloy layer at the interface with the third land 38, the alloy layer can increase the bonding strength between the third land 38 and the fourth via conductor 71. This can increase the connection reliability between the first wiring 40 and the fourth wiring 70.

[0076] 3 , in the wiring board 1, at least a portion of the third land 38 may extend into the bonding layer 27. At least a portion of the third land 38 in the thickness direction may extend into the bonding layer 27. The entire third land 38 in the thickness direction may extend into the bonding layer 27.

[0077] At least a portion of the third land 38 located on the second surface 102 of the inorganic base material 10 penetrates into the bonding layer 27, thereby suppressing expansion or contraction in the X-axis direction shown in FIG. 3 , which is the direction along the seventh surface 107 or the eighth surface 108 of the bonding layer 27. This reduces the load on the interface between the inorganic base material 10 and the bonding layer 27, thereby improving the bonding reliability of the base material. Furthermore, at least a portion of the third land 38 penetrates into the bonding layer 27, thereby reducing the thickness of the wiring substrate 1. This allows the wiring substrate 1 to be made smaller.

[0078] Furthermore, in the wiring board 1, at least a portion of the fourth land 63 may extend into the bonding layer 27. At least a portion of the fourth land 63 in the thickness direction may extend into the bonding layer 27. The entire fourth land 63 in the thickness direction may extend into the bonding layer 27.

[0079] At least a portion of the fourth land 63 located on the ninth surface 109 of the second organic base material 30 penetrates into the bonding layer 27, thereby suppressing expansion or contraction of the bonding layer 27 in the X-axis direction. This reduces the load on the interface between the second organic base material 30 and the bonding layer 27, thereby improving the bonding reliability of the base material. Furthermore, at least a portion of the fourth land 63 penetrates into the bonding layer 27, thereby reducing the thickness of the wiring substrate 1. This allows the wiring substrate 1 to be miniaturized.

[0080] 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. 4. Fig. 4 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.

[0081] The wiring pitch on the tenth surface 110, 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. 4 , the wiring arrangement may be arranged at a narrower pitch on each base material from the motherboard side toward the semiconductor element 3 side. In other words, in the wiring substrate 1, the wiring pitch may be gradually narrower from the motherboard side toward the semiconductor element 3 side. This reduces the wiring pitch from the second organic base material 30 toward the first organic base material 20. Therefore, in the wiring substrate 1, for example, the semiconductor element 3 can be connected to the first wiring 40 on the sixth surface 106 of the first organic base material 20, and the motherboard can be connected to the third wiring 60 on the outer surface of the second organic base material 30.

[0082] 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 substrate 1, an area A1 to which the first organic layer 21 is not bonded is located on the first surface 101 of the inorganic base material 10. According to the wiring substrate 1 of this embodiment, the location of the area A1 on the first surface 101 of the inorganic base material 10 allows the heat dissipation of the wiring substrate 1 to be improved.

[0083] 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.

[0084] The embodiments disclosed herein 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.

[0085] The present technology can also be configured as follows: (1) A wiring board comprising: an inorganic base material mainly composed of ceramic; a conductor located inside a through hole penetrating the inorganic base material; a first organic base material including a plurality of first organic layers containing an organic component and bonded to a first surface of the inorganic base material; a second organic base material including an organic component and bonded to a second surface of the inorganic base material opposite the first surface; and bonding layers located between the first organic base material and the inorganic base material and between the second organic base material and the inorganic base material, respectively, wherein 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. (2) The wiring board according to (1), wherein the second organic base material includes a plurality of second organic layers. (3) The wiring board according to (1) or (2), wherein the bonding layer is a thermosetting resin. (4) The wiring board according to any one of (1) to (3), wherein the bonding layer has a third surface bonded to the first surface and a fourth surface located opposite the third surface, the first organic base material has a fifth surface bonded to the fourth surface and a sixth surface located opposite the fifth surface, a first wiring located inside the first organic base material and extending from the fifth surface to the sixth surface, and a second wiring located inside the bonding layer and extending from the third surface to the fourth surface, the conductor has a first land located on the first surface and electrically connected to the conductor, the first wiring has a first via conductor and a second land located on the fifth surface and electrically connected to the first via conductor, the second wiring has a second via conductor connecting between the first land and the second land, and at least a portion of the first land and the second land extends into the bonding layer.(5) The wiring board according to any one of (1) to (4), wherein the bonding layer has a seventh surface bonded to the second surface and an eighth surface located opposite the seventh surface, the first organic base material has a ninth surface bonded to the eighth surface and a tenth surface located opposite the ninth surface, a third wiring located inside the second organic base material and extending from the ninth surface to the tenth surface, and a fourth wiring located inside the bonding layer and extending from the seventh surface to the eighth surface, the conductor has a third land located on the second surface and electrically connected to the conductor, the third wiring has a third via conductor and a fourth land located on the ninth surface and electrically connected to the third via conductor, the fourth wiring has a fourth via conductor connecting the third land and the fourth land, and at least a portion of the third land and the fourth land extends into the bonding layer. (6) The wiring board according to any one of (1) to (5), wherein 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. (7) The wiring board according to any one of (1) to (6), wherein at least the second organic base material has a core layer containing glass cloth. (8) The wiring board according to any one of (1) to (7), wherein the ceramic is low-temperature co-fired ceramic. (9) A semiconductor device comprising: the wiring board according to any one of (1) to (8); and a semiconductor element mounted on the wiring board.

[0086] REFERENCE SIGNS LIST 1 wiring substrate 3 semiconductor element 10 inorganic base material 11 ceramic layer 12 first through hole 20 first organic base material 21 first organic layer 22 reinforcing layer 25 bonding layer 27 bonding layer 30 second organic base material 31 second organic layer 32 reinforcing layer 35 first conductor 36 through-hole via 37 first land 38 third land 40 first wiring 41 first via conductor 42 first wiring layer 43 second land 50 second wiring 51 third via conductor 60 third wiring 61 second via conductor 62 second wiring layer 63 fourth land 70 fourth wiring 71 fourth via conductor 101 first surface 102 second surface 103 third surface 104 fourth surface 105 fifth surface 106 sixth surface 107 seventh surface 108 eighth surface 109 9th surface 110 10th surface 111 11th surface 112 12th surface 113 13th surface 114 14th surface 115 15th surface 116 16th surface 117 17th surface 118 18th surface A1 area

Claims

1. A wiring board comprising: an inorganic base material whose main component is ceramic; a conductor located inside a through hole that penetrates the inorganic base material; a first organic base material that includes a plurality of first organic layers containing an organic component and is bonded to a first surface of the inorganic base material; a second organic base material that contains an organic component and is bonded to a second surface of the inorganic base material that is located opposite to the first surface; and bonding layers located between the first organic base material and the inorganic base material, and between the second organic base material and the inorganic base material, respectively; wherein 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.

2. The wiring board according to claim 1, wherein the second organic base material includes a plurality of second organic layers.

3. The wiring board according to claim 1 or 2, wherein the bonding layer is made of a thermosetting resin.

4. The wiring board according to any one of claims 1 to 3, wherein the bonding layer has a third surface bonded to the first surface and a fourth surface located opposite the third surface, the first organic base material has a fifth surface bonded to the fourth surface and a sixth surface located opposite the fifth surface, a first wiring located inside the first organic base material and extending from the fifth surface to the sixth surface, and a second wiring located inside the bonding layer and extending from the third surface to the fourth surface, the conductor is located on the first surface and has a first land electrically connected to the conductor, the first wiring has a first via conductor and a second land located on the fifth surface and electrically connected to the first via conductor, the second wiring has a second via conductor connecting the first land and the second land, and at least a portion of the first land and the second land extend into the bonding layer.

5. The wiring board according to any one of claims 1 to 4, wherein the bonding layer has a seventh surface bonded to the second surface and an eighth surface located opposite the seventh surface, the first organic base material has a ninth surface bonded to the eighth surface and a tenth surface located opposite the ninth surface, a third wiring located inside the second organic base material and extending from the ninth surface to the tenth surface, and a fourth wiring located inside the bonding layer and extending from the seventh surface to the eighth surface, the conductor is located on the second surface and has a third land electrically connected to the conductor, the third wiring has a third via conductor and a fourth land located on the ninth surface and electrically connected to the third via conductor, the fourth wiring has a fourth via conductor connecting the third land and the fourth land, and at least a portion of the third land and the fourth land extends into the bonding layer.

6. The wiring board according to any one of claims 1 to 5, wherein 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.

7. The wiring board according to any one of claims 1 to 6, wherein at least the second organic base material has a core layer containing glass cloth.

8. The wiring board according to any one of claims 1 to 7, wherein the ceramic is a low-temperature co-fired ceramic.

9. A semiconductor device comprising: a wiring board according to any one of claims 1 to 8; and a semiconductor element mounted on said wiring board.

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