Wiring board and semiconductor device

Abstract

This wiring board is provided with a core base material, a first wiring base material, a second wiring base material, first wiring, and second wiring. The core base material has a first surface and a second surface positioned opposite to the first surface. The first wiring base material has a third surface joined to the first surface and a fourth surface positioned opposite to the third surface, and contains an organic material. The second wiring base material has a fifth surface joined to the second surface, and a sixth surface positioned opposite to the fifth surface, and contains an organic material. The first wiring is located on the first wiring base material and extends from the third surface to the fourth surface. The second wiring is located on the second wiring base material and extends from the fifth surface to the sixth surface. The core base material includes a first core material, a second core material, a first organic layer, a second organic layer, at least one through-hole, and a connection conductor.

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 that has an organic layer on which wiring is formed, and the organic layer may contain a reinforcing material such as glass cloth.

[0003] A through-hole portion is formed in the wiring board, and the through-hole portion has a through-hole that penetrates the wiring board and a conductor located inside the through-hole (see Patent Document 1).

[0004] JP 2023-111608 A

[0005] The wiring board of the present disclosure includes a core substrate, a first wiring substrate, a second wiring substrate, a first wiring, and a second wiring. The core substrate has a first surface and a second surface opposite the first surface. The first wiring substrate has a third surface bonded to the first surface and a fourth surface opposite the third surface, and contains an organic material. The second wiring substrate has a fifth surface bonded to the second surface and a sixth surface opposite the fifth surface, and contains an organic material. The first wiring is located on the first wiring substrate and extends from the third surface to the fourth surface. The second wiring is located on the second wiring substrate and extends from the fifth surface to the sixth surface. The core substrate includes a first core material, a second core material, a first organic layer, a second organic layer, at least one through hole, and a connecting conductor. The first core material is primarily composed of an inorganic component. The second core material is located on at least both sides of the first core material in a direction perpendicular to the stacking direction of the core substrate, first wiring substrate, and second wiring substrate, and contains an organic component and a reinforcing material. The first organic layer contains an organic component and contacts the first core material and the second core material on one side in the stacking direction. The second organic layer contains an organic component and contacts the first core material and the second core material on the other side in the stacking direction. The through hole penetrates the first organic layer, the first core material, and the second organic layer. The connecting conductor is located inside the through hole and electrically connects the first wiring and the second wiring.

[0006] FIG. 1 is a schematic cross-sectional view showing the configuration of a wiring board according to a first embodiment. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a schematic enlarged view of region III in FIG. 1. FIG. 4 is a schematic cross-sectional view showing the configuration of a wiring board according to a second embodiment. FIG. 5 is a schematic cross-sectional view showing the configuration of a wiring board according to a third embodiment. FIG. 6 is a schematic cross-sectional view showing the configuration of a wiring board according to a fourth embodiment. FIG. 7 is a schematic cross-sectional view showing the configuration of a wiring board according to a fifth embodiment. FIG. 8 is a cross-sectional perspective view taken along line VIII-VIII in FIG. 7. FIG. 9 is a schematic enlarged view of region IX in FIG. 7. FIG. 10 is a schematic cross-sectional view showing the configuration of a wiring board according to a sixth embodiment. FIG. 11 is an explanatory diagram showing an example of a method for manufacturing a wiring board. FIG. 12 is a schematic cross-sectional view showing an example of a semiconductor device configuration. FIG. 13 is a schematic cross-sectional view showing the configuration of a wiring board according to a seventh embodiment. FIG. 14 is a schematic cross-sectional view showing the configuration of a wiring board according to an eighth embodiment. FIG. 15 is an explanatory diagram showing an example of a method for manufacturing a wiring board.

[0007] 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.

[0008] 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.

[0009] 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 orthogonal to each other, and the positive Z-axis direction is the vertically upward direction. Note that the horizontal direction in this disclosure refers to the XY plane direction.

[0010] The above-mentioned conventional techniques have room for improvement in terms of increasing the rigidity of the wiring board.

[0011] The present disclosure provides a technique that can increase the rigidity of a wiring board.

[0012] First Embodiment First, the configuration of a wiring board according to a first embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic cross-sectional view showing the configuration of a wiring board 1 according to the first embodiment. FIG. 2 is a schematic cross-sectional view taken along line II-II shown in FIG. 1. FIG. 3 is a schematic enlarged view of region III shown in FIG. 1. Note that through holes 15, connecting conductors 16, and organic resin 22 are omitted from FIG. 2.

[0013] 1 , wiring board 1 has a core substrate 10, a first wiring substrate 40, and a second wiring substrate 50. Wiring board 1 is a laminate of core substrate 10, first wiring substrate 40, and second wiring substrate 50. Wiring board 1 has first wiring 60 on first wiring substrate 40 and second wiring 70 on second wiring substrate 50. Wiring board 1 also has connecting conductors 16 on core substrate 10, which electrically connect first wiring 60 and second wiring 70.

[0014] <Core Substrate> The core substrate 10 includes a first core material 11 , a second core material 12 , a first organic layer 13 , a second organic layer 14 , through holes 15 , and connecting conductors 16 .

[0015] <First Core Material> The first core material 11 is a ceramic substrate primarily composed of an inorganic component. The first core material 11 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 the crystallization of a portion 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 first core material 11 formed using ceramic in this manner has higher rigidity than a core material made of glass.

[0016] For example, the first core material 11 may be LTCC (Low Temperature Co-fired Ceramics). When LTCC is used as the first core material 11, the first core material 11 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 within the first core material 11. In this embodiment, a low-melting-point metal refers to a metal with a melting point lower than that of typical metals used for wiring in ceramic substrates, such as tungsten or molybdenum. However, the first core material 11 may also be a ceramic other than LTCC, such as alumina (aluminum oxide), SiN (silicon nitride), or AlN (aluminum nitride).

[0017] First core material 11 may contain ceramic filler as ceramic particles. Examples of ceramic filler that can be used include alumina (aluminum oxide), calcium titanate, and magnesium titanate. First core material 11 containing alumina has particularly high rigidity.

[0018] The first core material 11 has a seventh surface 107 and an eighth surface 108 located opposite the seventh surface 107. The first core material 11 may be a plate-like body having the seventh surface 107 and the eighth surface 108 as its main surfaces. The edges of the first core material 11 may be rounded. This can reduce chipping of the first core material 11.

[0019] In an embodiment, the first core material 11 may have one ceramic layer 17. In the example shown in Fig. 1, the first core material 11 has one ceramic layer 17, but the number of ceramic layers 17 is not limited to one. The number of ceramic layers 17 may be multiple.

[0020] When there are a plurality of ceramic layers 17, the plurality of ceramic layers 17 are stacked along the thickness direction of the first core material 11. In a wiring board 1 having such a first core material 11, internal wiring may be formed within the first core material 11 by co-firing, allowing for a high degree of freedom in design.

[0021] <Second Core Material> The second core material 12 contains an organic component. The organic component may be an organic resin. Examples of the organic resin include epoxy resin, bismaleimide-triazine resin, polyimide resin, acrylic resin, polycarbonate resin, olefin resin, and polyphenylene resin. The organic resin may also be polytetrafluoroethylene (PTFE), other fluororesins, or polyphenylene ether resin. The second core material 12 may contain glass cloth. Glass cloth refers to fibrous glass fiber (an example of a reinforcing material) impregnated with the organic resin. Examples of reinforcing materials include insulating fabric materials such as glass fiber, glass nonwoven fabric, aramid nonwoven fabric, aramid fiber, and polyester fiber. Only one type of reinforcing material may be used, or two or more types may be used in combination. In the present disclosure, the second core material 12 may contain an organic component, for example, as a material occupying 15% or more by volume of the material.

[0022] The second core material 12 has a ninth surface 109 and a tenth surface 110 located opposite the ninth surface 109. As shown in Fig. 2, the second core material 12 is frame-shaped, and the first core material 11 may be located inside the inner edge of the second core material 12. The second core material 12 is, for example, rectangular frame-shaped and is configured to surround the first core material 11 on all four sides.

[0023] Second core material 12 does not need to be frame-shaped, and it need only be located on at least both horizontal sides of first core material 11 in a cross-sectional view taken along the stacking direction of first wiring substrate 40 and second wiring substrate 50. In other words, second core material 12 needs only to face at least two sides of first core material 11. Second core material 12 may also face three sides of first core material 11.

[0024] The second core material 12 may have a higher rigidity than the first organic layer 13, the second organic layer 14, the first wiring substrate 40, and the second wiring substrate 50. This increases the rigidity of the core substrate 10. Furthermore, by positioning the second core material 12, which is made of organic resin, on the outside of the wiring substrate 1, it is possible to protect the first core material 11, which is made of ceramic and is more prone to chipping than organic resin. Furthermore, by positioning the second core material 12 on the outside of the wiring substrate 1, it is possible to improve the processability of the end face of the wiring substrate 1 compared to when the first core material 11 is positioned on the outside of the wiring substrate 1. Note that the core substrate 10 may also be configured without the second core material 12.

[0025] The second core material 12 may have organic resin 18 filled between it and the first core material 11. The organic resin 18 may be the same as the organic resin contained in the first organic layer 13 and the second organic layer 14. The organic resin 18 is highly flexible because it does not contain reinforcing materials such as glass fiber or glass nonwoven fabric. This allows the organic resin 18 to relieve stress caused by the difference in thermal expansion between the first core material 11 and the second core material 12. Therefore, even if there is a thermal effect during mounting, the behavior of the wiring board 1 can be stabilized. The thickness of the second core material 12 is not particularly limited and may be, for example, 100 μm or more and 2 mm or less.

[0026] For example, when the first core material 11 is ceramic, the thermal expansion coefficient of the first core material 11 is 3 ppm / K to 12 ppm / K (RT to 400°C). When the first core material 11 is LTCC, the thermal expansion coefficient of the first core material 11 is 3 ppm / K to 12 ppm / K (RT to 400°C). When the first core material 11 is alumina, the thermal expansion coefficient of the first core material 11 is about 7 ppm / K (RT to 400°C). When the first core material 11 is AlN, the thermal expansion coefficient of the first core material 11 is about 5 ppm / K (RT to 400°C). When the second core material 12 is a material obtained by curing prepreg, the thermal expansion coefficient of the second core material 12 is 13 ppm / K to 18 ppm / K (α1). When the organic resin 18 is the same as the organic resin contained in the first organic layer 13 and the second organic layer 14, the thermal expansion coefficient of the organic resin 18 is 20 ppm / K to 30 ppm / K (α1). The thermal expansion coefficient indicates the thermal expansion coefficient in the planar direction. RT (Room Temperature) refers to room temperature. Room temperature is, for example, about 20 to 25°C. α1 is a temperature lower than the glass transition temperature.

[0027] <First Organic Layer> The first organic layer 13 contains an organic component. The organic component may be an organic resin. The first organic layer 13 may be, for example, an insulating resin film (ABF) manufactured by Ajinomoto Fine-Techno Co., Ltd. The organic resin may be, for example, an epoxy resin containing silica particles, a polyimide resin, a bismaleimide-triazine resin, an acrylic resin, a polycarbonate resin, an olefin resin, or a polyphenylene resin. The organic resin may be, for example, polytetrafluoroethylene (PTFE), other fluororesins, or polyphenylene ether resins. The first organic layer 13 may be composed of a single organic resin layer. In the present disclosure, the first organic layer 13 may contain an organic component as a material that accounts for, for example, 15% or more by volume of the material.

[0028] The first organic layer 13 has an eleventh surface 111 and a first surface 101 located opposite the eleventh surface 111. The first organic layer 13 may be a plate-like body having the first surface 101 and the eleventh surface 111 as its main surfaces. The first organic layer 13 contacts the first core material 11 and the second core material 12 on one side in the stacking direction. For example, the eleventh surface 111 of the first organic layer 13 is bonded to the eighth surface 108 of the first core material 11 and the ninth surface 109 of the second core material 12.

[0029] The first core material 11 and the first organic layer 13 are bonded together by, for example, hydrogen bonding. Specifically, the first core material 11 and the first organic layer 13 are bonded together by bonding between hydroxyl groups of the first core material 11 and the first organic layer 13. In this case, a ceramic material such as alumina having surface hydroxyl groups may be used for the first core material 11, and an epoxy resin, which is a resin material containing hydroxyl groups, may be used for the first organic layer 13. By directly bonding the first core material 11 and the first organic layer 13 in this way, the thickness of the wiring substrate 1 can be reduced.

[0030] <Second Organic Layer> The second organic layer 14 contains an organic component. The organic component may be an organic resin. The organic resin contained in the second organic layer 14 may be the same as the organic resin contained in the first organic layer 13. The second organic layer 14 may be composed of a single organic resin layer. Note that in the present disclosure, the second organic layer 14 may contain the organic component as a material that occupies, for example, 15% by volume or more of the material.

[0031] The second organic layer 14 has a twelfth surface 112 and a second surface 102 located opposite the twelfth surface 112. The second organic layer 14 may be a plate-like body having the second surface 102 and the twelfth surface 112 as its main surfaces. The second organic layer 14 contacts the first core material 11 and the second core material 12 on the other side in the stacking direction. For example, the twelfth surface 112 of the second organic layer 14 is bonded to the seventh surface 107 of the first core material 11 and the tenth surface 110 of the second core material 12.

[0032] The first core material 11 and the second organic layer 14 are bonded together by, for example, hydrogen bonding. Specifically, the first core material 11 and the second organic layer 14 are bonded together by bonding between hydroxyl groups of the first core material 11 and the second organic layer 14. In this case, a ceramic material such as alumina having surface hydroxyl groups may be used for the first core material 11, and an epoxy resin, which is a resin material containing hydroxyl groups, may be used for the second organic layer 14. By directly bonding the first core material 11 and the second organic layer 14 in this way, the thickness of the wiring substrate 1 can be reduced.

[0033] <Through Hole> The wiring substrate 1 according to the embodiment has at least one through hole 15. The through hole 15 penetrates the first organic layer 13, the first core material 11, and the second organic layer 14. For example, the through hole 15 penetrates from the first surface 101 to the second surface 102 of the core substrate 10.

[0034] <Connecting Conductor> The connecting conductor 16 may have a through-hole conductor 19. The through-hole conductor 19 is located continuously across the first organic layer 13, the first core material 11, and the second organic layer 14. The connecting conductor 16 may have a land 20 on the first surface 101 of the core substrate 10. It may also have a land 21 on the second surface 102 of the core substrate 10. The lands 20 and 21 are electrically connected to the through-hole conductor 19. Note that the lands 20 and 21 are not located on the seventh surface 107 or the eighth surface 108 of the first core material 11.

[0035] Connection conductor 16 is mainly composed of metal and extends along the side surface of through hole 15. Specifically, through-hole conductor 19 is located in through hole 15 and extends along the side surface of through hole 15. Connection conductor 16 is located inside through hole 15 and electrically connects first wiring 60 and second wiring 70.

[0036] In connection conductor 16, the side surface of through hole 15 may be electrically connected by copper-plated through-hole conductor 19, and the inside of through-hole conductor 19 may be filled with organic resin 22. In addition, connection conductor 16 may have a conductive paste filled inside through-hole conductor 19, or through hole 15 may be entirely filled with copper plating. Filling all through hole 15 with a metal conductor can further increase the conductivity of connection conductor 16.

[0037] 3 , the diameter of the through hole 15 in the first core material 11 may be smaller than the diameter of the through hole 15 in the first organic layer 13 and the second organic layer 14. This may form a step in the through-hole conductor 19, and the first core material 11 may contact the first organic layer 13 and the second organic layer 14 in a stepped manner at the step. Furthermore, when an organic resin having a reinforcing material is used for the first organic layer 13 and the second organic layer 14, the reinforcing material may protrude into the through hole 15, and copper plating may be formed on top of it. By having the reinforcing material protruding into the copper plating, the copper plating can be firmly adhered to the inside of the through hole 15.

[0038] <First Wiring Substrate> The first wiring substrate 40 contains an organic component. The organic component may be an organic resin. The organic resin contained in the first wiring substrate 40 may be the same as the organic resin contained in the first organic layer 13. In the present disclosure, the first wiring substrate 40 may contain the organic component as a material that accounts for, for example, 15% by volume or more of the material.

[0039] The first wiring substrate 40 has a third surface 103 and a fourth surface 104 located opposite the third surface 103. The first wiring substrate 40 may be a plate-like body having the third surface 103 and the fourth surface 104 as main surfaces. The first wiring substrate 40 may have a semiconductor element 80 (see FIG. 12 ) mounted on the fourth surface 104.

[0040] The first wiring substrate 40 may have multiple organic resin layers 41. The multiple organic resin layers 41 are stacked along the thickness direction of the first wiring substrate 40. A wiring board 1 having such a first wiring substrate 40 has a high degree of design freedom. In the example shown in FIG. 1 , the first wiring substrate 40 has five organic resin layers 41, but the number of organic resin layers 41 is not limited to five. The number of organic resin layers 41 may be two, three, four, or six or more. Furthermore, a solder resist may be located on the fourth surface 104 of the first wiring substrate 40. The solder resist has openings for electrically connecting the build-up conductor layer and the electrodes of the electronic component via solder.

[0041] <Second Wiring Substrate> The second wiring substrate 50 contains an organic component. The organic component may be an organic resin. The organic resin contained in the second wiring substrate 50 may be the same as the organic resin contained in the first organic layer 13. The first organic layer 13, the second organic layer 14, the first wiring substrate 40, and the second wiring substrate 50 in the first embodiment may all be ABF. Note that in the present disclosure, the second wiring substrate 50 may contain the organic component as a material that accounts for, for example, 15% by volume or more of the material.

[0042] The second wiring substrate 50 has a fifth surface 105 and a sixth surface 106 located opposite the fifth surface 105. The second wiring substrate 50 may be a plate-like body having the fifth surface 105 and the sixth surface 106 as main surfaces. The sixth surface 106 of the second wiring substrate 50 may be bonded to a motherboard (not shown).

[0043] The second wiring substrate 50 may have multiple organic resin layers 51. The multiple organic resin layers 51 are stacked along the thickness direction of the second wiring substrate 50. A wiring board 1 having such a second wiring substrate 50 has a high degree of design freedom. In the example shown in FIG. 1 , the second wiring substrate 50 has five organic resin layers 51, but the number of organic resin layers 51 is not limited to five. The number of organic resin layers 41 may be two to four, or six or more. Furthermore, a solder resist may be located on the sixth surface 106 of the second wiring substrate 50. The solder resist has openings for electrically connecting the build-up conductor layer and the electrodes of the electronic component via solder.

[0044] The wiring board 1 according to the embodiment can increase rigidity while achieving finer wiring and narrower pitches by combining the core substrate 10, the first wiring substrate 40, and the second wiring substrate 50. Since warping of the board becomes more pronounced as the board becomes larger, the configuration of the wiring board 1 in which the core substrate 10 compensates for the low rigidity of the first wiring substrate 40 and the second wiring substrate 50 is particularly useful for increasing the size of the board.

[0045] Furthermore, since the amount of ceramic used is smaller than when the entire core substrate 10 is made of ceramic, it is possible to reduce the weight and cost of the core substrate 10. Therefore, it is possible to reduce the weight and cost of the wiring board 1.

[0046] Furthermore, by positioning the through-hole conductors 19 in the first core material 11, insulation deterioration due to ion migration between the through-hole conductors 19 via the glass cloth does not occur, compared to when the through-hole conductors 19 are positioned in a core including glass cloth, and therefore the density of the through-hole conductors 19 can be increased.

[0047] <First Wiring and Second Wiring> The first wiring 60 is located on the first wiring substrate 40 and extends from the third surface 103 to the fourth surface 104. The first wiring 60 has a plurality of vias 61 and a plurality of wiring layers 62. The vias 61 penetrate one or a plurality of organic resin layers 41. The wiring layers 62 are located between adjacent organic resin layers 41 and electrically connect the plurality of vias 61 to each other.

[0048] The second wiring 70 is located on the second wiring substrate 50 and extends from the fifth surface 105 to the sixth surface 106. The second wiring 70 has a plurality of vias 71 and a plurality of wiring layers 72. The vias 71 penetrate one or a plurality of organic resin layers 51. The wiring layers 72 are located between adjacent organic resin layers 51 and electrically connect the plurality of vias 71 to each other.

[0049] The connecting conductor 16, the first wiring 60, and the second wiring 70 may be, for example, a metal conductor whose main component is copper. For example, the connecting conductor 16, the first wiring 60, and the second wiring 70 may all be a metal conductor whose main component is copper.

[0050] By using metal conductors whose main component is copper for all of the connecting conductor 16, the first wiring 60, and the second wiring 70, it is possible to obtain high electrical properties and high corrosion resistance, in which even if corrosion occurs, it will only occur on the surface and will not penetrate into the interior, compared to, for example, a case in which any of the connecting conductor 16, the first wiring 60, and the second wiring 70 is a metal conductor other than copper.

[0051] Of the connecting conductor 16, the first wiring 60, and the second wiring 70, only the portion of the connecting conductor 16 that is in contact with the first core material 11 may contain a glass component. In this case, the connecting conductor 16 is firmly bonded to the first core material 11, which also contains a glass component, via the glass component. This allows the rigidity of the core substrate 10 to be increased.

[0052] The first wiring 60 may be electrically and thermally connected to the semiconductor element 80 (see FIG. 12 ). By thermally connecting the first wiring 60, which is mainly composed of copper, which has a relatively high thermal conductivity, to the semiconductor element 80, which serves as a heat source, the heat generated from the semiconductor element 80 can be efficiently released to a motherboard or the like via the first wiring 60, the connecting conductor 16, and the second wiring 70.

[0053] Second Embodiment In the above first embodiment, an example has been described in which the first organic layer 13, the second organic layer 14, the first wiring substrate 40, and the second wiring substrate 50 are made of the same organic resin. The wiring substrate 1 is not limited to this, and as shown in Fig. 4, the first organic layer 13 and the second organic layer 14 may be made of an organic resin different from that of the first wiring substrate 40 and the second wiring substrate 50. Fig. 4 is a schematic cross-sectional view showing the configuration of a wiring substrate 1 according to a second embodiment.

[0054] The first organic layer 13 and the second organic layer 14 may be formed from prepreg. The prepreg is a semi-cured reinforcing material such as glass cloth impregnated with an organic resin, and is then laminated to the first core material 11 and the second core material 12, followed by thermocompression bonding using a heat press to obtain the core substrate 10. The organic resin contained in the prepreg may be the same as the organic resin contained in the second core material 12. The organic resin 18 filled between the first core material 11 and the second core material 12 may be an organic resin that has flowed out from the prepreg before curing. A filler contained in the prepreg may also be contained in the organic resin 18.

[0055] The first organic layer 13 and the second organic layer 14 contain a reinforcing material such as glass cloth, and therefore have higher rigidity than the first wiring substrate 40 and the second wiring substrate 50. This can further improve the rigidity of the wiring board 1.

[0056] Furthermore, when the thermal expansion coefficients of first organic layer 13 and second organic layer 14 are higher than that of first core material 11 and lower than that of first wiring substrate 40 and second wiring substrate 50, by interposing first organic layer 13 between core substrate 10 and first wiring substrate 40, stress applied to through-hole conductor 19 and land 20 can be alleviated compared to when first organic layer 13 is not interposed. Furthermore, by interposing second organic layer 14 between core substrate 10 and second wiring substrate 50, stress applied to through-hole conductor 19 and land 21 can be alleviated compared to when second organic layer 14 is not interposed. This can improve connection stability over the long term.

[0057] When the modulus of elasticity (vertical) of first organic layer 13 and second organic layer 14 is higher than the modulus of elasticity of first core material 11 but lower than the modulus of elasticity of first wiring substrate 40 and second wiring substrate 50, by interposing first organic layer 13 between core substrate 10 and first wiring substrate 40, when stress that bends wiring substrate 1 in the vertical direction (stacking direction) due to heat generated when mounting semiconductor element 80 on wiring substrate 1 is applied, the force that tries to peel first organic layer 13 and second organic layer 14 from core substrate 10, and the force that tries to peel first wiring substrate 40 and second wiring substrate 50 from first organic layer 13 and second organic layer 14, can be alleviated compared to when first organic layer 13 is not interposed. Therefore, the presence of first organic layer 13 and second organic layer 14 makes it possible to realize a high-quality wiring substrate 1 with low risk of interlayer delamination.

[0058] For example, the thermal expansion coefficient of first organic layer 13 and second organic layer 14 is 13 ppm / K to 18 ppm / K (α1). Note that first organic layer 13 and second organic layer 14 may be configured to have a smaller thermal expansion coefficient than first wiring substrate 40 and second wiring substrate 50 by including a larger amount of filler such as silica than first wiring substrate 40 and second wiring substrate 50.

[0059] 5 is a schematic cross-sectional view showing the configuration of a wiring substrate 1 according to a third embodiment. As shown in FIG. 5, the wiring substrate 1 may have a two-layer structure including a first organic layer 13 and a second organic layer 14.

[0060] First organic layer 13 may include a first layer 24 in contact with first core material 11 and second core material 12, and a second layer 25 in contact with first wiring substrate 40. Second organic layer 14 may include a first layer 26 in contact with first core material 11 and second core material 12, and a second layer 27 in contact with first wiring substrate 40.

[0061] The first layers 24, 26 may be ABF. The second layers 25, 27 may be formed from prepreg. The rigidity of the second layers 25, 27 may be higher than the rigidity of the first layers 24, 26. By forming the first organic layer 13 and the second organic layer 14 into a two-layer structure, the core substrate 10 can be formed thicker. Furthermore, a material containing an organic resin with high fillability between the first core material 11 and the second core material 12 can be selected for the organic resin layer of the first layers 24, 26. If an ABF containing an epoxy resin or a material containing an organic resin with high fillability is selected for the organic resin layer of the first layers 24, 26, the organic resin contained in the first layers 24, 26 before curing melts and flows out between the first core material 11 and the second core material 12, making it easier to fill the gap between the first core material 11 and the second core material 12 with resin without gaps.

[0062] 6 is a schematic cross-sectional view showing the configuration of a wiring substrate 1 according to a fourth embodiment. As shown in Fig. 6, the wiring substrate 1 may have a two-layer structure including a first organic layer 13 and a second organic layer 14, and first layers 28 and 30 may be undercoat inks.

[0063] First organic layer 13 may include a first layer 28 in contact with first core material 11 and second core material 12, and a second layer 29 in contact with first wiring substrate 40. Second organic layer 14 may include a first layer 30 in contact with first core material 11 and second core material 12, and a second layer 31 in contact with first wiring substrate 40.

[0064] The first layers 28, 30 may be undercoat ink. The undercoat ink may be a thermosetting resin used to planarize the surface of a printed wiring board. The undercoat ink easily penetrates into the gap between the first core material 11 and the second core material 12, thereby facilitating the production of the core substrate 10. The second layers 29, 31 may be formed from prepreg. The thermal expansion coefficient of the first layers 28, 30 may be higher than that of the first core material 11. The thermal expansion coefficient of the second layers 29, 31 may be higher than that of the first layer 28 and lower than that of the first organic layer 13 or the second organic layer 14. This allows the wiring board 1 to more effectively relieve stress than, for example, a single-layer structure in which the first organic layer 13 and the second organic layer 14 are formed from prepreg.

[0065] Fifth Embodiment Fig. 7 is a schematic cross-sectional view showing the configuration of a wiring substrate 1 according to a fifth embodiment. Fig. 8 is a cross-sectional perspective view taken along line VIII-VIII shown in Fig. 7. Fig. 9 is a schematic enlarged view of region IX shown in Fig. 7. As shown in Figs. 7 to 9, the wiring substrate 1 may have an organic resin 32 interposed between the first core material 11 and the through hole 15.

[0066] The first core material 11 may have a communicating hole 33 communicating between the first surface 101 and the second surface 102. The through hole 15 may be located inside the communicating hole 33, and an organic resin 32 may be filled between the communicating hole 33 and the through hole 15. The organic resin 32 may be the same as the organic resin contained in the first organic layer 13 and the second organic layer 14. In this way, in the process of forming the through hole 15, only the organic resin 32 is drilled, so that steps are not formed on the side surfaces of the through hole 15, and the through hole 15 can be formed with high accuracy. Since the entire inner wall surface of the through hole 15 can be formed with the organic resin, stress generated between the first core material 11 and the first organic layer 13 and the second organic layer 14 can be reduced, and conductivity reliability can be improved.

[0067] The organic resin 32 may be the same as the organic resin contained in the prepreg. Furthermore, in the two-layer structure shown in Figures 5 and 6, the organic resin 32 may be filled between the communicating hole 33 and the through-hole 15. In this case, the first layer and the organic resin 32 may be the same as the organic resin contained in the ABF, and the second layer may be formed from a prepreg. Furthermore, the first layer and the organic resin 32 may be an undercoat ink, and the second layer may be formed from a prepreg.

[0068] As shown in Figure 8, when the through hole 15 is viewed from the Z-axis direction, the first core material 11, organic resin 32, through-hole conductor 19, and organic resin 22 may be located in this order from the radial outside to the radial inside of the through hole 15.

[0069] As shown in FIG. 9, the through-hole conductor 19 may be formed so that its width narrows toward the center between the lands 20 and 21 .

[0070] 10 is a schematic cross-sectional view showing the configuration of a wiring substrate 1 according to a sixth embodiment. As shown in Fig. 10, the surface of the second core material 12 facing the first core material 11 may be inclined with respect to the stacking direction.

[0071] The surface of second core material 12 facing first core material 11 is inclined, so that the opening on ninth surface 109 side is wider than the opening on tenth surface 110 side. This makes it easier to insert first core material 11 into the frame of second core material 12 during the manufacture of wiring board 1.

[0072] <Manufacturing Flows According to First to Sixth Embodiments> FIG. 11 is an explanatory diagram showing an example of a method for manufacturing the wiring substrate 1. As shown in FIG.

[0073] As shown in Figure 11, in the manufacturing method of wiring board 1, second core material 12 is introduced. Next, cavity (through-hole) processing is performed. Next, tape 34 is attached to second core material 12. Next, first core material 11 is embedded in second core material 12. Next, first organic layer 13 is embedded. Next, tape 34 is peeled off from second core material 12. Next, second organic layer 14 is embedded. Next, holes are drilled with a laser to form through-holes 15.

[0074] Next, copper plating is performed to form through-hole conductors 19. The copper plating is performed by first performing electroless plating, followed by electrolytic plating. Next, organic resin 22 is embedded in connection conductors 16, and cap plating is performed. Next, patterning is performed to form lands 20 and 21. Next, ABF lamination is performed. Next, laser via processing is performed. Next, patterning is performed to form vias 61 and 71 and wiring layers 62 and 72. In the example shown in FIG. 11 , wiring board 1 is manufactured by repeating ABF lamination, laser via processing, and patterning.

[0075] 13 is a schematic cross-sectional view showing the configuration of a wiring board 1 according to a seventh embodiment. The wiring board 1 according to the seventh embodiment differs from the wiring board 1 according to the first embodiment in that, during the manufacturing process, a first core material 11 on which a through-hole conductor 19 is formed in advance is embedded in a second core material 12.

[0076] 13 , the wiring substrate 1 may have electrode pads 91 located on each of the first surface 101 and the second surface 102, and via conductors 92 that penetrate the first organic layer 13 and the second organic layer 14, respectively. The electrode pads 91 may be provided on both ends of a through-hole conductor 19. The through-hole conductor 19 may be entirely filled with a metal conductor. The via conductor 92 may be connected to the electrode pad 91 and the land 20. The electrode pad 91 may have a larger diameter than the land 20. The inside of the through-hole conductor 19 may be filled with an organic resin 22.

[0077] The first core material 11 may be manufactured by copper plating a ceramic plate having through holes 15 to form through-hole conductors 19. The through holes 15 are formed by plating with CO ２ The ceramic plate may be formed by laser processing using a laser or the like, blasting processing, or drilling processing. The ceramic plate may be, for example, a single plate or a laminate of low temperature co-fired ceramics (LTCC). The ceramic plate may be made of SiC, AlN, and Al. ２ O３ may also be used.

[0078] 14 is a schematic cross-sectional view showing the configuration of a wiring board 1 according to an eighth embodiment. The wiring board 1 according to the eighth embodiment differs from the wiring board 1 according to the seventh embodiment in that the first core material 11, which is a ceramic laminate, is embedded in the second core material 12 during the manufacturing process.

[0079] As shown in Fig. 14, the wiring board 1 may have interlayer wiring 94 located inside the first core material 11. Specifically, the first core material 11 may have multiple ceramic layers 95. The first core material 11 may have via conductors 96 that penetrate one or multiple ceramic layers 95. The multiple ceramic layers 95 may be stacked along the Z-axis direction shown in Fig. 14, which is the thickness direction of the first core material 11. The interlayer wiring 94 may be located between adjacent ceramic layers 95 and electrically connect the multiple via conductors 96 together. The wiring board 1 may also have lands 97 that absorb stacking misalignment of the via conductors 96.

[0080] The first core material 11 may be produced by firing a laminate of ceramic green sheets. The ceramic green sheets may be, for example, LTCC green sheets. The laminate of LTCC green sheets may contain a conductor paste containing a metal such as Cu between the layers. Constrained firing may be performed in which the laminate of LTCC green sheets is fired while being constrained by glass plates or the like. This makes it possible to adjust the amount of shrinkage of the LTCC green sheets during firing.

[0081] <Manufacturing Flow According to Seventh and Eighth Embodiments> FIG. 15 is an explanatory diagram showing an example of a method for manufacturing the wiring substrate 1. As shown in FIG.

[0082] As shown in FIG. 15 , in the manufacturing method of the wiring board 1, the second core material 12 is introduced. Next, cavity (through-hole) processing is performed. Next, tape 34 is attached to the second core material 12. Next, the first core material 11 according to the seventh embodiment, in which through-hole vias have been previously formed in the second core material 12, is embedded. At this time, a resin ink or the like may be filled into the cavity (through-hole) of the second core material 12 to fill the gap between the second core material 12 and the first core material 11. Next, the first organic layer 13 is embedded. Next, the tape 34 is peeled off from the second core material 12. Next, the wiring board 1 being manufactured is turned upside down, and the second organic layer 14 is embedded. Next, holes are drilled by laser processing or drilling to form through-holes 93 in each of the first organic layer 13 and the second organic layer 14. Next, copper plating is performed to form via conductors 92 in the through-holes 93. At this time, circuit formation may be performed in addition to the formation of the via conductors 92. Next, organic resin layers 41, 51 containing a thermosetting resin may be built up on the first organic layer 13 and the second organic layer 14, respectively. For example, the organic resin layers 41, 51 may be made of one or both of an insulating resin film (ABF) manufactured by Ajinomoto Fine-Techno Co., Ltd. and a prepreg. When a prepreg is used as the organic resin layers 41, 51, a copper foil may be used to form part of the conductor.

[0083] The wiring board 1 according to the eighth embodiment may be manufactured by embedding the first core material 11 according to the eighth embodiment in the second core material 12 instead of the first core material 11 according to the seventh embodiment.

[0084] 12 is a schematic cross-sectional view showing an example of the configuration of a semiconductor device 100. As shown in Fig. 12, the semiconductor device 100 includes a wiring substrate 1 and a semiconductor element 80. The semiconductor element 80 is mounted on the fourth surface 104 of the first wiring substrate 40 of the wiring substrate 1.

[0085] The semiconductor device 100 according to the embodiment can increase the rigidity of the wiring substrate 1, thereby more stabilizing the mounting surface of the semiconductor device 100. The inclusion of the first core material 11 in the core substrate 10 makes the coefficient of thermal expansion of the core substrate 10 closer to that of silicon, the main component of the semiconductor element 80, than that of organic resin (including those containing glass cloth), thereby providing the effect of making the connection less likely to break when stress is applied in the surface direction during operation of the semiconductor device 100.

[0086] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0087] The present technology can also be configured as follows: (1) A core substrate having a first surface and a second surface opposite to the first surface, a first wiring substrate containing an organic material and having a third surface bonded to the first surface and a fourth surface opposite to the third surface, a second wiring substrate containing an organic material and having a fifth surface bonded to the second surface and a sixth surface opposite to the fifth surface, a first wiring located on the first wiring substrate and extending from the third surface to the fourth surface, and a second wiring located on the second wiring substrate and extending from the fifth surface to the sixth surface, wherein the core substrate comprises: a first core material mainly composed of an inorganic component, second core materials located on at least both sides of the first core material in a direction perpendicular to a stacking direction of the core substrate, the first wiring substrate, and the second wiring substrate, the second core material containing an organic component and a reinforcing material, and a first organic layer containing an organic component and in contact with the first core material and the second core material on one side of the stacking direction, A wiring board comprising: a second organic layer containing an organic component and in contact with the first core material and the second core material on the other side of the stacking direction; at least one through hole penetrating the first organic layer, the first core material, and the second organic layer; and a connection conductor located inside the through hole and electrically connecting the first wiring and the second wiring. (2) The wiring board according to (1), wherein the second core material is frame-shaped and the first core material is located inside an inner edge of the second core material. (3) The wiring board according to (1) or (2), wherein the first wiring substrate and the second wiring substrate have multiple organic resin layers, and the first wiring and the second wiring have: multiple vias penetrating one or more of the organic resin layers; and a wiring layer electrically connecting the multiple vias and located between adjacent organic resin layers. (4) The wiring board according to any one of (1) to (3), wherein the first organic layer and the second organic layer have higher rigidity than the first wiring substrate and the second wiring substrate. (5) The wiring board according to (4), wherein the first organic layer and the second organic layer contain a reinforcing material. (6) The wiring board according to any one of (1) to (5), wherein an organic resin is filled between the first core material and the second core material.(7) The wiring board according to (6), wherein the thermal expansion coefficient of the organic resin is higher than that of the first core material and lower than that of the second core material. (8) The wiring board according to any one of (1) to (7), wherein the first core material has a communicating hole communicating between the first surface and the second surface, the through hole is located inside the communicating hole, and an organic resin is filled between the communicating hole and the through hole. (9) The wiring board according to any one of (1) to (8), wherein the first organic layer and the second organic layer include a first layer in contact with the first core material and the second core material, and a second layer in contact with the first wiring substrate or the second wiring substrate, and wherein the rigidity of the second layer is higher than the rigidity of the first layer. (10) The wiring board according to any one of (1) to (9), wherein the first organic layer and the second organic layer include a first layer in contact with the first core material and the second core material, and a second layer in contact with the first wiring substrate or the second wiring substrate, wherein a thermal expansion coefficient of the first layer is higher than that of the first core material, and a thermal expansion coefficient of the second layer is higher than that of the first layer and lower than that of the first organic layer or the second organic layer. (11) A semiconductor device comprising: the wiring board according to any one of (1) to (10); and a semiconductor element mounted on the wiring board.

[0088] REFERENCE SIGNS LIST 1 wiring substrate 10 core substrate 11 first core material 12 second core material 13 first organic layer 14 second organic layer 15 through hole 16 connecting conductor 17 ceramic layer 18 organic resin 19 through-hole conductor 20 land 21 land 22 organic resin 24 first layer 25 second layer 26 first layer 27 second layer 28 first layer 29 second layer 30 first layer 31 second layer 32 organic resin 33 communicating hole 34 tape 40 first wiring substrate 41 organic resin layer 50 second wiring substrate 51 organic resin layer 60 first wiring 61 via 62 wiring layer 70 second wiring 71 via 72 wiring layer 80 semiconductor element 100 semiconductor device 101 first surface 102 second surface 103 3rd side 104 4th side 105 5th side 106 6th side 107 7th side 108 8th side 109 9th side 110 10th side 111 11th side 112 12th side

Claims

1. A core substrate having a first surface and a second surface opposite the first surface; a first wiring substrate containing an organic material, having a third surface bonded to the first surface and a fourth surface opposite the third surface; a second wiring substrate containing an organic material, having a fifth surface bonded to the second surface and a sixth surface opposite the fifth surface; a first wiring located on the first wiring substrate and extending from the third surface to the fourth surface; and a second wiring located on the second wiring substrate and extending from the fifth surface to the sixth surface, wherein the core substrate comprises: a first core material mainly composed of an inorganic component; second core materials containing an organic component and a reinforcing material, located on at least both sides of the first core material in a direction perpendicular to the stacking direction of the core substrate, the first wiring substrate, and the second wiring substrate; and a first organic layer containing an organic component and in contact with the first core material and the second core material on one side of the stacking direction. a second organic layer containing an organic component and in contact with the first core material and the second core material on the other side of the stacking direction; at least one through hole penetrating the first organic layer, the first core material, and the second organic layer; and a connection conductor located inside the through hole and electrically connecting the first wiring and the second wiring.

2. The wiring board according to claim 1, wherein the second core material is frame-shaped, and the first core material is positioned inside the inner edge of the second core material.

3. A wiring board according to claim 1 or 2, wherein the first wiring substrate and the second wiring substrate have a plurality of organic resin layers, and the first wiring and the second wiring have a plurality of vias penetrating one or more of the organic resin layers, and a wiring layer electrically connecting the plurality of vias and located between adjacent organic resin layers.

4. The wiring board according to any one of claims 1 to 3, wherein the first organic layer and the second organic layer have higher rigidity than the first wiring substrate and the second wiring substrate.

5. The wiring board according to claim 4, wherein the first organic layer and the second organic layer include a reinforcing material.

6. The wiring board according to any one of claims 1 to 5, wherein an organic resin is filled between the first core material and the second core material.

7. The wiring board according to claim 6, wherein the thermal expansion coefficient of said organic resin is higher than that of said first core material and lower than that of said second core material.

8. A wiring board according to any one of claims 1 to 7, wherein the first core material has a through hole connecting the first surface and the second surface, the through hole is located inside the through hole, and an organic resin is filled between the through hole and the through hole.

9. A wiring board according to any one of claims 1 to 8, wherein the first organic layer and the second organic layer include a first layer in contact with the first core material and the second core material, and a second layer in contact with the first wiring substrate or the second wiring substrate, and the rigidity of the second layer is higher than the rigidity of the first layer.

10. A wiring board as described in any one of claims 1 to 9, wherein the first organic layer and the second organic layer include a first layer in contact with the first core material and the second core material, and a second layer in contact with the first wiring substrate or the second wiring substrate, wherein the thermal expansion coefficient of the first layer is higher than the thermal expansion coefficient of the first core material, and the thermal expansion coefficient of the second layer is higher than the thermal expansion coefficient of the first layer and lower than the thermal expansion coefficient of the first organic layer or the second organic layer.

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

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