Organic core material and manufacturing method thereof, laminate including organic core material, and wiring board

Abstract

A production method for an organic core material according to the present invention comprises: a step for preparing a plurality of pieces of first prepreg, each having a first fiber cloth and a first resin layer which comprises a first resin component and in which the first fiber cloth is embedded; a step for preparing at least two pieces of second prepreg, each having a second fiber cloth and a second resin layer which comprises a second resin component and in which the second fiber cloth is embedded; and a step for heating a laminate which comprises a piece of the second prepreg, a plurality of pieces of the first prepreg, and a piece of the second prepreg in this order, while applying pressing pressure thereto in the thickness direction thereof, wherein the content of the second resin component with respect to the mass of the second prepreg is higher than the content of the first resin component with respect to the mass of the first prepreg.

Description

[Technical Field]

[0001] The present disclosure relates to an organic core material and a method for producing the same, a laminate including the organic core material, and a wiring board. [Background technology]

[0002] In recent years, electronic devices have become increasingly smaller, lighter, and more multifunctional. Accordingly, printed wiring boards and semiconductor packages that mount LSIs (Large Scale Integration) are required to have higher density and higher reliability. Patent Document 1 discloses a wiring substrate that achieves high density wiring layers. Patent Document 2 discloses a printed wiring board and a semiconductor device that achieve excellent connection reliability. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-191968 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-056371 Summary of the Invention [Problem to be solved by the invention]

[0004] To achieve even higher density and reliability in semiconductor packages, the requirements for thickness accuracy of organic core materials are becoming increasingly stringent. The prepreg used to manufacture organic core materials contains fiber cloth, such as glass cloth, as a reinforcing material. Paragraph

[0057] of Patent Document 2 describes the manufacture of organic core materials through a process in which multiple prepreg sheets are sandwiched between metal foils and press-molded. According to the inventors' investigations, the fiber cloth present in the prepreg causes waviness on the surface of the organic core material obtained by press-molding. This surface waviness can cause a decrease in yield in the manufacture of semiconductor packages.

[0005] For example, when mounting a semiconductor chip with fine solder bumps on a wiring layer formed on an organic core material, the surface waviness of the organic core material tends to reduce the connection yield between the wiring and the solder bumps. Furthermore, when forming wiring with a wiring width / space width of 2 / 2 μm or less using the semi-additive process (SAP) on an insulating layer formed on an organic core material, the surface waviness tends to reduce the yield of photoresist pattern formation, resulting in a decrease in wiring yield. Even when forming wiring wider than 2 / 2 μm, variations in the width of the photoresist pattern tend to cause variations in wiring width, which increases transmission loss when signals are passed through the wiring.

[0006] The present disclosure provides an organic core material useful for achieving higher density and higher reliability in semiconductor packages, a method for producing the same, a laminate including the organic core material, and a wiring board. [Means for solving the problem]

[0007] The method for producing an organic core material according to the present disclosure uses at least two types of prepregs (first and second prepregs). The first prepreg has a first fiber cloth and a first resin layer made of a first resin component and in which the first fiber cloth is embedded. The second prepreg has a second fiber cloth and a second resin layer made of a second resin component and in which the second fiber cloth is embedded. The second prepreg is richer in resin components than the first prepreg. That is, the content of the second resin component based on the mass of the second prepreg is higher than the content of the first resin component based on the mass of the first prepreg. The content of the second resin component based on the mass of the second prepreg is, for example, 60% by mass or more.

[0008] A first aspect of the method for producing an organic core material according to the present disclosure includes the steps of preparing a plurality of first prepregs, preparing at least two second prepregs, and heating a laminate including the second prepreg, the plurality of first prepregs, and the second prepreg in this order while applying a pressure in the thickness direction (hereinafter sometimes referred to as a "heat pressing step"). By performing the heat pressing step with the plurality of first prepregs sandwiched between the resin-rich second prepregs, an organic core material can be produced in which surface waviness caused by the fiber cloth is sufficiently reduced.

[0009] In a second aspect of the method for producing an organic core material according to the present disclosure, a laminate of multiple first prepregs is subjected to a heat-pressing process, and then a second heat-pressing process is performed with second prepregs placed on both surfaces of the laminate. Specifically, this method includes the steps of preparing multiple first prepregs, preparing at least two second prepregs, heating the first laminate of the multiple first prepregs while applying a pressure in the thickness direction, and heating a second laminate comprising the second prepreg, the first laminate, and the second prepreg, in this order, while applying a pressure in the thickness direction. By performing the heat-pressing process with the first laminate sandwiched between the resin-rich second prepregs, an organic core material can be produced with sufficiently reduced surface waviness due to the fiber cloth.

[0010] These manufacturing methods allow the production of organic core materials with sufficiently flat surfaces. By using such organic cores, fine wiring can be formed with high precision. The sufficiently flat surface of the organic core can be demonstrated by measuring the thickness of the organic core at multiple points and finding that the standard deviation of the measured values ​​is sufficiently small. In the organic core material according to the present disclosure, the standard deviation of the thickness at four points corresponding to the vertices of a square with sides of 50 mm in plan view is, for example, 3.5 μm or less.

[0011] A first aspect of the organic core material according to the present disclosure has a laminated structure including a first layer and a second layer. The first layer has a first fiber cloth and a first resin layer made of a first resin component and in which the first fiber cloth is embedded. The second layer has a second fiber cloth and a second resin layer made of a second resin component and in which the second fiber cloth is embedded. The second layer is richer in resin component than the first layer. The organic core material according to the first aspect has a laminated structure including a second layer, a plurality of first layers, and a second layer in this order, wherein the content of the second resin component based on the mass of the second layer is higher than the content of the first resin component based on the mass of the first layer.

[0012] The resin-rich second layer disposed near the surface of the organic core material provides the organic core material with a sufficiently flat surface, which is useful for achieving higher density and higher reliability in semiconductor packages.

[0013] In a second embodiment of the organic core material according to the present disclosure, fiber cloths and resin layers are alternately arranged in a longitudinal cross section, and the standard deviation of thickness at four points corresponding to the vertices of a square with sides of 50 mm in plan view is 3.5 μm or less. In the longitudinal cross section of this organic core material, a fiber cloth thinner than the fiber cloth arranged in the center of the organic core material is arranged near the surface of the organic core material (see FIG. 2(c)). By arranging a thin fiber cloth near the surface of the organic core material, surface waviness caused by the fiber cloth can be suppressed. Organic cores with flat surfaces are useful for achieving even higher density and higher reliability in semiconductor packages.

[0014] The laminate according to the present disclosure includes the organic core material and an insulating layer provided on the surface of the organic core material. Because the organic core material has excellent thickness precision, the laminate also has excellent thickness precision. Specifically, in a planar view, the laminate has a standard deviation of thickness of 4.0 μm or less at four points corresponding to the vertices of a square with sides of 50 mm. The wiring board according to the present disclosure includes the organic core material. By using an organic core material with excellent thickness precision, fine wiring with a width of 0.5 to 10 μm can be stably formed. [Effects of the Invention]

[0015] According to the present disclosure, there are provided an organic core material and a method for producing the same, a laminate including the organic core material, and a wiring board that are useful for achieving higher density and higher reliability in semiconductor packages. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating one embodiment of an organic core material according to the present disclosure. [Figure 2] 2(a) to 2(c) are SEM photographs showing enlarged cross sections of organic core materials according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a cross-sectional view that schematically shows a state in which a metal foil is disposed on the surface of a laminate that includes the first and second prepregs. [Figure 4] 4(a) to 4(c) are cross-sectional views that schematically show the manufacturing process of the organic core material shown in FIG. [Figure 5] 5(a) to 5(c) are cross-sectional views that schematically show the steps of manufacturing a microwiring board using an organic core material according to the present disclosure. [Figure 6] 6(a) to 6(c) are cross-sectional views that schematically show the steps of manufacturing a microwiring board using an organic core material according to the present disclosure. [Figure 7] FIG. 7 is a cross-sectional view that schematically illustrates a microwiring board manufactured using an organic core material according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, several embodiments of the present disclosure will be described in detail, but the present invention is not limited to the following embodiments.

[0018] <Organic core material> FIG. 1 is a cross-sectional view schematically illustrating an organic core material according to this embodiment. The organic core material 10 shown in FIG. 1 has a laminated structure including a first layer 1 and a second layer 2. That is, the organic core material 10 has a laminated structure including a second layer 2, a plurality of first layers 1, and a plurality of second layers 2, in this order. While FIG. 1 illustrates an embodiment in which the first layer 1 has six layers, the number of first layers 1 is not limited to six. Furthermore, the second layers 2 constituting the surfaces F1 and F2 of the organic core material 10 do not have to be single layers, but may each be multiple layers.

[0019] The thickness of the organic core material 10 is, for example, 500 to 1600 μm, and may be 600 to 1400 μm. A thickness of 500 μm or more tends to suppress warping of the organic core material 10, improving handleability. On the other hand, a thickness of 1600 μm or less tends to suppress deterioration in handleability due to weight. The thickness of the organic core material 10 can be adjusted, for example, by the number of first layers 1, or may be adjusted by the number of second layers 2. The width of the organic core material 10 is, for example, 200 to 1300 mm from the viewpoint of productivity.

[0020] The first layer 1 has a first fiber cloth 1a and a first resin layer 1B made of a first resin component and in which the first fiber cloth 1a is embedded. The second layer 2 has a second fiber cloth 2a and a second resin layer 2B made of a second resin component and in which the second fiber cloth 2a is embedded. The fiber cloths 1a and 2a are composed of weft threads (wave lines in FIG. 1) and warp threads (ovals in FIG. 1). The second layer 2 is richer in resin component than the first layer 1. That is, the content of the second resin component based on the mass of the second layer is higher than the content of the first resin component based on the mass of the first layer.

[0021] The first layer 1 is formed by curing prepreg P1, and the second layer 2 is formed by curing prepreg P2 (see Figure 3). To make the second layer 2 richer in resin components than the first layer 1, prepreg P2 may be used that is richer in resin components than prepreg P1. To make the second layer 2 richer in resin components than the first layer 1, for example, prepreg P2 may be used that has a relatively thick second resin layer 2b, or prepreg P2 may be used that has a relatively thin second fiber cloth 2a. The dashed dotted lines in Figure 1 indicate the boundaries between layers.

[0022] 2(a) to 2(c) are SEM photographs showing an enlarged cross section of an organic core material according to this embodiment. FIG. 2(a) is an SEM photograph showing the overall structure of the organic core material in the thickness direction from surface F1 to surface F2. FIG. 2(b) is an SEM photograph showing the surface F1 side at a larger magnification than FIG. 2(a), and FIG. 2(c) is an SEM photograph showing the surface F1 side at a larger magnification than FIG. 2(b). Second layers 2 (cured second prepregs) are disposed near surfaces F1 and F2, respectively, and eight first layers 1 (cured first prepregs) are disposed between them. Note that the resin components of adjacent prepregs often become integrated after curing, and the boundary between the two may not be clearly discernible even when observed in an SEM photograph.

[0023] On the other hand, observation of the longitudinal cross section using an SEM confirms that the resin layer 3 and the fiber cloths (fiber cloths 1a, 2a) are arranged alternately. The SEM photographs shown in Figures 2(a) to 2(c) show an example in which fiber cloth 2a, which is thinner than fiber cloth 1a arranged in the center of the organic core material, is arranged near the surface of the organic core material. By arranging a cured prepreg body containing thin fiber cloth near the surface of the organic core material, surface waviness caused by the fiber cloth can be suppressed.

[0024] The fiber cloths 1a and 2a are, for example, woven or nonwoven fabrics containing inorganic fibers. Examples of fibers constituting the fiber cloth include natural fibers such as paper and cotton linters; inorganic fibers such as glass fibers and asbestos; organic fibers such as aramid, polyimide, polyvinyl alcohol, polyester, tetrafluoroethylene, and acrylic; and mixtures thereof. Among these, glass fibers are preferred from the viewpoint of flame retardancy. Examples of glass fibers include woven fabrics using E-glass, C-glass, D-glass, S-glass, etc., or glass woven fabrics in which short fibers are bonded with an organic binder; and blends of glass fibers and cellulose fibers. Glass woven fabrics using E-glass are more preferred. Glass fibers, carbon fibers, or combinations thereof may also be used.

[0025] At least one of the fiber cloth 1a and the fiber cloth 2a may be a woven fabric, or both may be woven fabrics. A prepreg containing a woven fabric has the following advantages over a prepreg containing a nonwoven fabric. (1) It is easy to fabricate organic core materials with small thickness variations. Because woven fabrics have little thickness variation, the prepregs obtained by impregnating woven fabrics with resin components also have little thickness variation. Therefore, using prepregs containing woven fabrics makes it easy to produce organic core materials with little thickness variation. However, because nonwoven fabrics have randomly distributed fibers, differences in fiber density can occur depending on the location, so the prepregs obtained by impregnating nonwoven fabrics with resin components may have large thickness variation. (2) It is easy to fabricate organic core materials with little warping. When a laminate is produced by forming a resin layer (e.g., a build-up layer) on the surface of an organic core material, the difference in thermal expansion coefficient between the resin layer and the organic core material can cause internal stress, which can lead to warping of the laminate. Woven fabrics have a higher elastic modulus and greater rigidity than nonwoven fabrics, which is thought to be able to suppress warping. Furthermore, woven fabrics have a stronger restraining force in the in-plane direction of the organic core material than nonwoven fabrics, which is thought to reduce the thermal expansion of the organic core material itself in the in-plane direction. (3) It is easy to prepare an organic core material with excellent durability. Because woven fabrics are made of woven fibers, they are considered to be stronger (more tenacity) than nonwoven fabrics. Therefore, organic core materials containing woven fabrics are considered to have better durability than organic core materials containing nonwoven fabrics. (4) The organic core material can be easily and efficiently produced. Woven fabrics are less likely to stretch under tension than nonwoven fabrics, and therefore, for example, it is possible to efficiently produce prepregs with excellent dimensional stability and organic core materials containing them by roll-to-roll processing. Furthermore, because the woven fabric itself is rigid, it is easy to maintain its shape after impregnation with a resin component, and it is therefore easy to transport in this state.

[0026] The fiber cloth may have the form of, for example, a woven fabric, a nonwoven fabric, a roving, a chopped strand mat, a surfacing mat, etc. The material and shape are selected depending on the intended use or performance of the molded product, and one type may be used alone, or two or more types of materials and shapes may be combined as necessary.

[0027] The thickness of the fiber cloths 1a, 2a is, for example, 0.01 to 0.5 mm, and may be 0.015 to 0.2 mm or 0.02 to 0.15 mm from the viewpoints of formability and enabling high-density wiring. From the viewpoints of heat resistance, moisture resistance, processability, etc., the fiber cloth is preferably one that has been surface-treated with a silane coupling agent or the like, or one that has been mechanically opened.

[0028] The first and second resin layers 1B and 2B (resin layer 3) are made of a cured product of a thermosetting resin composition. These layers contain organic components and, if necessary, inorganic components (e.g., inorganic filler) as resin components. In layers 1 and 2, the components excluding the inorganic fiber component (fiber cloth) can be considered to be the resin component.

[0029] The resin component content in the first layer 1 may be 20 to 90% by mass relative to the mass of the first layer 1, or 20 to 80% by mass from the viewpoint of reducing the linear expansion coefficient, 30 to 90% by mass from the viewpoint of reducing voids after lamination, or 40 to 90% by mass from the viewpoint of further improving the flatness of the substrate material. Meanwhile, as described above, the second layer 2 is richer in resin components than the first layer 1. That is, the resin component content in the second layer 2 may be 60 to 95% by mass relative to the mass of the second layer 2, or 60 to 80% by mass from the viewpoint of reducing the linear expansion coefficient, 65 to 95% by mass from the viewpoint of reducing voids after lamination, or 70 to 95% by mass from the viewpoint of further improving the flatness of the substrate material. The resin component contents in both the first layer 1 and the second layer 2 may be 85% by mass or less. By ensuring that this content is 85% by mass or less, the flow of the resin component can be suppressed when the prepregs that make up the first layer 1 and the second layer 2 are produced by coating, which tends to prevent unevenness in the thickness of the resin layer.

[0030] The content of organic components in layers 1 and 2 can be calculated by methods such as ash content measurement. Ash content measurement is a method of calculating the proportion of organic components in the resin component by carbonizing the organic components at high temperature. An example of an inorganic component is inorganic filler. In layers 1 and 2, the components excluding the inorganic filler may be considered to be the resin component.

[0031] The mass ratio of the resin component contained in layers 1 and 2 can be calculated from a microscopic image of the cross section of the organic core material 10. The image of the cross section is binarized to calculate the area ratio of the fiber cloths 1a and 2a and the resin layers 1b and 2b. The area ratio is calculated as a volume ratio. The mass ratio can be calculated by multiplying the volume ratio of the fiber cloths 1a and 2a and the resin layers 1b and 2b by the specific gravity of each of the fiber cloths 1a and 2a and the resin layers 1b and 2b and integrating the results. The mass ratio of the resin component is calculated from the mass ratio.

[0032] For example, the method for calculating the mass ratio of the resin component for a prepreg in which the fiber cloth is glass cloth and the resin layer is made of a resin component whose main components are epoxy resin and fused silica will be explained. The specific gravity of glass cloth is about 2 to 3 g / cm. 3 The specific gravity of resins whose main components are epoxy resin and fused silica is approximately 0.8 to 2.5 g / cm 3 When the area ratio of the glass cloth to the resin component is 4:6, the mass ratio of the glass cloth to the resin component is between glass cloth:resin component = 4 x 3:6 x 0.8 = 25:10 and glass cloth:resin component = 4 x 2:6 x 2.5 = 5:10. The mass proportion of the resin component can be calculated from the mass ratio to be approximately 29 mass% to approximately 65 mass%.

[0033] For example, a fiber cloth with a specific gravity of 2.6 g / cm 3 Glass cloth, resin component specific gravity 1.8g / cm 3 When calculating the mass percentage of the resin component for a prepreg using a resin component whose main components are epoxy resin and fused silica, if the ratio of the area of ​​the resin content to the total cross-sectional area of ​​the prepreg is 69% or more, the mass percentage of the resin component will be 60% or more by mass.

[0034] The organic core material 10 has sufficiently flat surfaces F1, F2 due to the resin-rich second layer 2 being disposed near the surface of the organic core material 10. The organic core material 10 is useful for achieving higher density and higher reliability of semiconductor packages. The surface flatness of the organic core material 10 can be evaluated by measuring the thickness of the organic core material 10 at multiple different positions and using the standard deviation. The standard deviation of the thickness of the organic core material 10 may be 4 μm or less, 3.5 μm or less, 3 μm or less, 2.5 μm or less, or 2 μm or less, or may be 0.1 μm or more. The standard deviation of the thickness of the organic core material 10 is calculated by multiplying the thicknesses T1, T2, ..., T of the organic core material 10 at each of any n positions. n The value σ may be calculated from the following formula:

[0035]

number

[0036] The thickness of the organic core material 10 is measured at a position, for example, 2500 mm from the entire main surface of the organic core material 10. 2 The area is divided into multiple regions with an area of ​​2500mm, and one or more items can be selected from each region. 2 The entire main surface of the organic core material 10 is divided so as to maximize the number of regions having an area of ​​10 mm. The thickness is measured, for example, using a micrometer. For example, in a plan view of the organic core material 10, the standard deviation of the thickness at four points corresponding to the vertices of a square with sides of 50 mm is, for example, 3.5 μm or less, or may be 3 μm or less, 2.5 μm or less, or 2 μm or less, or may be 0.1 μm or more. The standard deviation of the thickness at four points corresponding to the vertices of a square with sides of 70 mm is, for example, 5.0 μm or less, or may be 4.5 μm or less, 4.0 μm or less, or 3.6 μm or less, or may be 0.1 μm or more.

[0037] (prepreg) The prepreg is produced, for example, by impregnating a fiber cloth with a thermosetting resin composition and then subjecting it to a heat treatment. Alternatively, the prepreg may be produced by preparing a film of the thermosetting resin composition in advance, sandwiching the fiber cloth between a pair of films, and then subjecting the film to a heat treatment. The heat treatment causes the thermosetting resin composition to enter a B-stage. From the viewpoint of its handleability and tackiness, the prepreg is preferably subjected to a cooling step in which it is cooled. The prepreg may be cooled by natural cooling or by using a cooling device such as a fan or a cooling roll. The temperature of the prepreg after cooling is usually 5 to 80°C, preferably 8 to 50°C, more preferably 10 to 30°C, and even more preferably room temperature. The thickness of a single prepreg is not particularly limited, but is preferably 20 to 150 μm, more preferably 60 to 120 μm, for example.

[0038] Examples of the thermosetting resin contained in the thermosetting resin composition include epoxy resins, phenolic resins, unsaturated imide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, modified silicone resins, triazine resins, melamine resins, urea resins, and furan resins. Furthermore, the thermosetting resin is not particularly limited to these, and any known thermosetting resin can be used. These may be used alone or in combination of two or more. Among these, epoxy resins, unsaturated imide resins, and modified silicone resins are preferred.

[0039] The epoxy resin is not particularly limited, but examples thereof include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and bisphenol S-type epoxy resins; alicyclic epoxy resins; aliphatic linear epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, bisphenol A novolac-type epoxy resins, and bisphenol F novolac-type epoxy resins; phenol aralkyl-type epoxy resins; stilbene-type epoxy resins; dicyclopentadiene-type epoxy resins; naphthalene-skeleton-containing epoxy resins such as naphthol novolac-type epoxy resins and naphthol aralkyl-type epoxy resins; biphenyl-type epoxy resins; biphenyl aralkyl-type epoxy resins; xylylene-type epoxy resins; and dihydroanthracene-type epoxy resins. Among these, naphthalene-skeleton-containing epoxy resins and naphthol aralkyl-type epoxy resins may be selected.

[0040] Examples of the unsaturated imide resin include maleimide resin, an addition reaction product of a maleimide resin with a monoamine compound, and a reaction product of a maleimide resin with a monoamine compound and a diamine compound. The maleimide compound is not particularly limited, and examples thereof include bis(4-maleimidophenyl)methane, polyphenylmethane maleimide, bis(4-maleimidophenyl)ether, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, m-phenylene bismaleimide, bis(4-maleimidophenyl)sulfone, bis(4-maleimidophenyl)sulfide, bis(4-maleimidophenyl)ketone, 2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, bis(4-(4-maleimidophenoxy)phenyl)sulfone, 4,4'-bis(3-maleimidophenoxy)biphenyl, 1,6-bismaleimido-(2,2,4-trimethyl)hexane, etc. Among these, bis(4-maleimidophenyl)methane may be selected.

[0041] The monoamine compound is preferably a monoamine compound having an acidic substituent (for example, a hydroxyl group, a carboxy group, etc.), and specific examples thereof include o-aminophenol, m-aminophenol, p-aminophenol, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3,5-dihydroxyaniline, and 3,5-dicarboxyaniline.

[0042] The diamine compound is preferably a diamine compound having at least two benzene rings, more preferably a diamine compound having at least two benzene rings in a linear chain between two amino groups, and examples thereof include 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyl-diphenylmethane, 4,4'-diamino-3,3'-diethyl-diphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, and 4,4'-diaminodiphenyl ketone. As the unsaturated imide resin, for example, a maleimide compound described in JP-A-2018-165340 can be used.

[0043] In addition to the thermosetting resin, the resin layers 1b and 2b preferably contain at least one selected from the group consisting of curing agents, curing accelerators, inorganic fillers, organic fillers, coupling agents, leveling agents, antioxidants, flame retardants, flame retardant assistants, thixotropic agents, thickeners, thixotropic agents, flexibility materials, surfactants, and photopolymerization initiators, as needed. In particular, in this embodiment, thickness accuracy can be improved without high inorganic filler loading. Therefore, the inorganic filler content can be, for example, 10 to 60 vol%, 20 to 60 vol%, or 30 to 60 vol%, with the upper limit of this range even being 57 vol% or 55 vol%. However, in cases where high inorganic filler loading is required, this embodiment does not necessarily prohibit the inorganic filler content from exceeding 60 vol%, and the upper limit of the range of the inorganic filler content can be, for example, 70 vol% or 80 vol%.

[0044] Also usable are thermosetting resin compositions containing, for example, a modified silicone compound (modified silicone resin) as described in International Publication No. 2012 / 099133, and, if necessary, at least one selected from the group consisting of other thermosetting resins, curing agents, curing accelerators, inorganic fillers, thermoplastic resins, elastomers, organic fillers, flame retardants, ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent brighteners, and adhesion improvers.

[0045] The modified silicone compound is preferably a silicone compound modified with amino groups at both ends, specifically a silicone compound modified with amino groups at both ends obtained by reacting (A) a siloxane diamine represented by the following general formula (1), (B) a maleimide compound having at least two N-substituted maleimide groups in its molecular structure, and (C) an amine compound having an acidic substituent represented by the following general formula (2), and details thereof are as described in WO 2012 / 099133.

[0046] [ka] [In formula (1), a plurality of R 1 each independently represents an alkyl group, a phenyl group, or a substituted phenyl group, and may be the same or different from each other; 2 each independently represents an alkyl group, a phenyl group, or a substituted phenyl group, and may be the same or different from each other; R 3 and R 4 each independently represents an alkyl group, a phenyl group, or a substituted phenyl group; R 5 and R 6 each independently represents a divalent organic group, and n represents an integer of 2 to 50.

[0047] [ka] [In formula (2), R 7 When there are a plurality of R, each independently represents a hydroxyl group, a carboxyl group, or a sulfonic acid group; 8When there are multiple x's, each independently represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 5 carbon atoms, or a halogen atom. x is an integer of 1 to 5, y is an integer of 0 to 4, and x+y=5.]

[0048] <Method of manufacturing organic core material> Next, a description will be given of a method for manufacturing the organic core material 10. The manufacturing method according to this embodiment includes the following steps. (A1) A step of preparing a plurality of first prepregs P1 (B1) A step of preparing at least two second prepregs P2 (C1) A step of heating a laminate 10P including a second prepreg P2, a plurality of first prepregs P1, and a second prepreg P2 in this order while applying a pressing force in the thickness direction.

[0049] FIG. 3 is a cross-sectional view schematically showing a state in which a metal foil is disposed on the surface of a laminate including prepregs P1 and P2. The first prepreg P1 has a first fiber cloth 1a and a first resin layer 1b made of a first resin component and in which the first fiber cloth 1a is embedded. The second prepreg P2 has a second fiber cloth 2a and a second resin layer 2b made of a second resin component and in which the second fiber cloth 2a is embedded. The second prepreg P2 has a resin component richer than the first prepreg P1. The first prepreg P1 becomes the first layer 1 by being cured. The second prepreg P2 becomes the second layer 2 by being cured.

[0050] The heat pressing step (C1) is carried out using, for example, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, or an autoclave molding machine, and may be carried out in a state where metal foils 5 are placed on the surfaces of the laminate 10P as shown in FIG.

[0051] The heat pressing temperature is, for example, 100 to 250°C. The heating and pressing time after the temperature increase is, for example, 0.1 to 5 hours. The organic core material after heating and pressing may be further heated if necessary. The laminate 10P is usually continuously pressed from the temperature increase to the heating and pressing at the heat pressing temperature. The pressure applied to the laminate 10P from the temperature increase to the heating and pressing at the heat pressing temperature may be, for example, 0.2 to 10 MPa. After the heat pressing step, the metal foil 5 is etched to obtain the organic core material 10. The metal foil 5 can be etched and removed using, for example, ferric chloride solution, ammonium persulfate, or the like.

[0052] In the above embodiment, the organic core material 10 is produced through a single heat-pressing process, but as will be described below, the organic core material 10 may be produced through two heat-pressing processes. That is, this production method includes the following steps. (A2) Step of preparing a plurality of first prepregs P1 (B2) A step of preparing at least two second prepregs P2 (C2) A step of heating a laminate 20P (first laminate) made up of a plurality of first prepregs P1 while applying a pressing force in the thickness direction. (D2) A step of heating a laminate 30P (second laminate) including a second prepreg P2, a laminate 20P, and a second prepreg P2 in this order while applying a pressing force in the thickness direction.

[0053] The heat pressing step of step (C2) may be carried out in a state where metal foil 5 is placed on each side of the laminate 20P, as shown in FIG. 4(a). After that, the metal foil 5 is etched, and then a second prepreg P2 is placed on each surface of the laminate 20 (cured laminate 20P) (see FIG. 4(b)). Furthermore, a metal foil 5 is placed on each surface of the second prepreg P2 (see FIG. 4(c)). In step (D2), the laminate P30 is subjected to a heat pressing step. Thereafter, the metal foil 5 is etched to obtain an organic core material 10.

[0054] By carrying out the curing treatment of the second prepreg P2 in a separate process from the curing treatment of the multiple first prepregs P1, the (D2) process can be carried out under conditions suitable for the curing treatment of the second prepreg P2, and the surface waviness of the organic core material 10 can be further suppressed.

[0055] A printed wiring board may be produced by subjecting the metal foil 5 on the surface of the organic core material 10 to circuit processing without etching the metal foil 5. From the viewpoint of electrical conductivity, the metal of the metal foil 5 is preferably copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, or an alloy containing at least one of these metal elements, more preferably copper or aluminum, and even more preferably copper. Circuit processing can be carried out, for example, by forming a resist pattern on the surface of the metal foil, removing unnecessary portions of the metal foil by etching, peeling off the resist pattern, forming necessary through holes with a drill, forming another resist pattern, plating to establish electrical continuity in the through holes, and finally peeling off the resist pattern.

[0056] A semiconductor package can be manufactured by mounting a semiconductor chip, memory, etc., at a predetermined position on a printed wiring board. The semiconductor package using the organic core material of this embodiment has small thickness variations, which tends to improve the yield when mounting semiconductor chips.

[0057] <Method of manufacturing a wiring board> A wiring board can be manufactured by forming fine wiring on the surface of a laminate containing an organic core material. Methods for forming fine wiring include the subtractive method, full additive method, semi-additive method (SAP: Semi-Additive Process), and modified semi-additive method (m-SAP: Modified Semi-Additive Process).

[0058] 5(a) to 5(c) and 6(a) to 6(c) are cross-sectional views schematically showing the steps of manufacturing a micro wiring board by a semi-additive method using an organic core material 10. A method of manufacturing a wiring board 50 shown in FIG. 7 will be described with reference to these figures.

[0059] Wiring board 50 is manufactured, for example, through the following process. (A) Step of forming insulating layers 15 on both sides of the organic core material 10 (see FIG. 5(a)) (B) A step of forming a seed layer 16 on the surface of one of the insulating layers 15 by, for example, sputtering or electroless plating (see FIG. 5(b)). (C) Step of forming a photosensitive resin layer 17 on the surface of the seed layer 16 (see FIG. 5(c)) (D) A step of forming a resist pattern by exposing and developing the photosensitive resin layer 17 (see FIG. 6(a)). (E) A step of forming wiring 18 by electrolytic plating in the area of ​​the surface of the seed layer 16 that is exposed from the resist pattern (see FIG. 6(b)). (F) Step of removing the resist pattern (see FIG. 6(c)). (H) Step of removing the seed layer 16 exposed by removing the resist pattern

[0060] The laminate 40 shown in FIG. 5(a) includes an organic core material 10 and an insulating layer 15. The insulating layer 15 can be formed from an insulating resin composition, and may be formed from a build-up film. The insulating layer 15 may be a single layer or a multilayer. The resin composition may be thermosetting or photosetting. The thickness of the insulating layer 15 is, for example, 10 to 360 μm, and may be 120 to 240 μm.

[0061] Because the thickness precision of the organic core material 10 is high, the laminate 40 also has excellent thickness precision. In a plan view of the laminate 40, the standard deviation of the thickness at four points corresponding to the vertices of a 50 mm square is, for example, 4.0 μm or less, and may be 3.8 μm or less, 3.4 μm or less, or 3.2 μm or less, or 0.1 μm or more. The standard deviation of the thickness at four points corresponding to the vertices of a 70 mm square is, for example, 4.4 μm or less, and may be 4.1 μm or less, 3.8 μm or less, or 3.6 μm or less, or 0.1 μm or more.

[0062] Through the above step (H), a circuit pattern including wiring 18 is formed on the surface of the insulating layer 15 (see FIG. 7). The wiring 18 has, for example, a fine trench structure. The width of the wiring 18 is, for example, 0.5 to 10 μm, and may be 0.5 to 5 μm. The interval (space width) between two adjacent wirings 18 is, for example, 0.5 to 10 μm, and may be 0.5 to 5 μm. [Example]

[0063] The present disclosure will be described in more detail below with reference to examples, although the present invention is not limited to the following examples.

[0064] [Examples 1 and 2] First, a prepreg was prepared according to the following procedure. 24 g of silicone diamine (trade name "KF-8010", manufactured by Shin-Etsu Silicones), 240 g of bis(4-maleimidophenyl)methane, and 400 g of propylene glycol monomethyl ether were placed in a flask equipped with a stirrer, a thermometer, and a nitrogen purge device, and the mixture was allowed to react at 115°C for 4 hours. After that, the temperature was raised to 130°C and the mixture was concentrated under normal pressure, yielding a solution with a resin content of 60% by mass. A mixture of 40 g of biphenyl aralkyl epoxy resin (trade name "NC-3000-H", manufactured by Nippon Kayaku Co., Ltd.) dissolved in propylene glycol monomethyl ether, 50 g of the above thermoplastic resin in solids, 0.5 g of curing accelerator (trade name "2P4MHZ-PW", manufactured by Shikoku Kasei Co., Ltd.), and 40 g of silica slurry (trade name "SC2050-KNK", manufactured by Admatechs Co., Ltd.) in solids was mixed with a predetermined amount of N-methyl-2-pyrrolidone and stirred for 30 minutes to become uniform, yielding a resin varnish containing the resin and silica slurry and having a solids content of 65 mass%.

[0065] A roll of glass cloth woven fabric (thickness: 0.1 mm, glass fiber: E-glass) was prepared. While the woven fabric was being pulled from this roll, it was impregnated with the varnish. This was heated and dried at 150°C for 10 minutes to produce a prepreg with a resin content of 50% by mass. On the other hand, another roll of glass cloth woven fabric (thickness: 0.015 mm, glass fiber: E-glass) was prepared. While the woven fabric was being pulled from this roll, it was impregnated with the varnish. This was heated and dried at 150°C for 10 minutes to produce a prepreg with a resin content of 70% by mass. The resin content of the prepreg included all components other than the glass cloth constituting the prepreg, including the components of the silica slurry, and was calculated. The resin content was measured by dividing the difference in mass between the prepreg and the glass cloth by the mass of the prepreg. The gap width during impregnation coating was repeatedly adjusted until prepregs with resin mass percentages of 50% and 70% were obtained. Through these processes, two types of prepregs with excellent dimensional stability were obtained. To prepare the organic core material, the two types of prepregs were cut to the specified size.

[0066] Six 250 mm square prepreg sheets with a 50% resin content were stacked on top of each other. A 270 mm square copper foil (5 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on the outside of the prepreg. A 260 mm square stainless steel plate (1.8 mm thick) was placed on the outside of that. Another 270 mm square copper foil (5 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on the outside of that. Five 265 mm square cushioning materials (0.2 mm thick, manufactured by Oji Paper Co., Ltd., KS190) were placed on the outside of that. Finally, another 260 mm square copper foil (12 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on each side of the prepreg. The resulting mixture was heated and pressurized using a press (Meiki Seisakusho, MHPC-VF-350-350-3-70) under conditions of a pressure of 3 MPa, a vacuum of 40 hPa, a heating rate of 4°C / min, and a holding time of 85 minutes at 240°C, to obtain the organic core material (see Figure 4(a)).

[0067] The resulting organic core material was immersed in an aqueous ammonium persulfate solution to etch the copper foil (see Figure 4(b)). A 250 mm square prepreg with a resin content of 70% by mass was placed on each of the top and bottom surfaces of the etched organic core material. A 270 mm square copper foil (5 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on the outside of the 70% resin prepreg (see Figure 4(c)). A 260 mm square stainless steel plate (1.8 mm thick) was placed on the outside of this copper foil, followed by a 270 mm square copper foil (5 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.), five 265 mm square cushioning materials (0.2 mm thick, manufactured by Oji Paper Co., Ltd., KS190) on the outside of this, and a 260 mm square copper foil (12 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.) on each of the other two surfaces. In this state, a press machine (MHPC-VF-350-350-3-70, manufactured by Meiki Seisakusho) was used to heat and pressurize the mixture under conditions of a pressure of 3 MPa, a vacuum of 40 hPa, a heating rate of 4°C / min, and a holding time of 85 minutes at a temperature of 240°C, thereby obtaining the organic core material of Example 1. An organic core material according to Example 2 was obtained in the same manner as in Example 1.

[0068] [Examples 3 and 4] After preparing prepregs in the same manner as in Example 1, six stacked 250 mm square prepregs each having a resin content of 50% by mass were placed on the top and bottom surfaces of a 250 mm square prepreg each having a resin content of 70% by mass. A 270 mm square copper foil (5 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on the outside of the 70% resin content prepreg (see FIG. 3 ). A 260 mm square stainless steel plate (1.8 mm thick) was placed on the outside of the copper foil, followed by a 270 mm square copper foil (5 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.), five 265 mm square cushioning materials (0.2 mm thick, manufactured by Oji Paper Co., Ltd., KS190) on the outside, and a 260 mm square copper foil (12 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.) on each side. In this state, a press machine (MHPC-VF-350-350-3-70 manufactured by Meiki Seisakusho) was used to heat and pressurize the mixture under conditions of a pressure of 3 MPa, a vacuum of 40 hPa, a heating rate of 4°C / min, and a holding time of 85 minutes at a temperature of 240°C, thereby obtaining the organic core material of Example 3. An organic core material according to Example 4 was obtained in the same manner as in Example 3.

[0069] [Comparative Examples 1 and 2] A prepreg was prepared in the same manner as in Example 1, and then eight 250 mm square prepregs each having a resin content of 50% by mass were stacked. On the outside of each prepreg, a 270 mm square copper foil (5 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed, and on the outside of each prepreg, a 260 mm square stainless steel plate (1.8 mm thick), a 270 mm square copper foil (5 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed, and on the outside of each prepreg, five 265 mm square cushioning materials (0.2 mm thick, manufactured by Oji Paper Co., Ltd., KS190) were placed, and on the outside of each prepreg, five 260 mm square copper foils (12 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.) were placed, and on each side of each prepreg, a pressure of 3 MPa, a vacuum of 40 hPa, a heating rate of 4 ° C. / min, and a holding time of 85 minutes at 240 ° C., to obtain an organic core material according to Comparative Example 1. An organic core material according to Comparative Example 2 was obtained in the same manner as in Comparative Example 1.

[0070] The organic core material obtained by the above method was evaluated according to the following evaluation methods. The results are shown in Tables 1 and 2.

[0071] <Calculating the standard deviation of thickness for a 50mm square size> The central 150mm square area of ​​a 250mm square organic core material (a square with sides of 250mm when viewed from above) was divided into nine 50mm square areas, and the standard deviation of the thickness of the nine areas was calculated. In the case of large packages for servers, it is assumed that the chip size will be around 50mm square, so 50mm squares were set as the range for calculating the standard deviation. Areas outside the central 150mm square were not used for evaluation because the resin contained in the prepreg flows out to the outside of the prepreg, making the organic core material thinner.

[0072] Using a micrometer (Mitutoyo Corporation, ID-C112X), thickness was measured at four points on the four corners of a 50 mm square area. The standard deviation was calculated using the thickness values ​​at the four points as the population. The maximum standard deviation value calculated from the nine areas is shown in Tables 1 and 2 as the standard deviation value for each organic core material.

[0073] <Calculation of standard deviation of thickness for 70mm square size> A 140mm square area in the center of a 250mm square organic core material (a square with sides of 250mm in plan view) was divided into four 70mm square areas, and the standard deviation of the thickness of the four areas was calculated. Because the UV irradiation area during photoresist pattern formation in the copper wiring formation process is 70mm square, this 70mm square was set as the range for calculating the standard deviation. Using a micrometer, the thickness was measured at four points on the four corners of the 70mm square area. The standard deviation was calculated using the thickness values ​​at the four points as the population. The maximum standard deviation value calculated from the four areas is shown in Tables 1 and 2 as the standard deviation value for each organic core material.

[0074] <Evaluation of yield of solder bump connections> An organic core material measuring 250 mm square (250 mm square in plan view) was prepared. The central region of this organic core material (a 150 mm square area) was cut into 30 mm square pieces using a cutting machine. A Refine Saw Excel A (manufactured by Refine Tech Co., Ltd.) was used for cutting. After cutting, the substrate surface was cleaned by immersion in a 10% by weight aqueous sulfuric acid solution for 1 minute. It was then washed with pure water.

[0075] After applying flux (SPARKLE FLUX WF-6317, manufactured by Senju Metal Industry Co., Ltd.) to the surface of the board, a chip with solder bumps (FBW150-0001JY, manufactured by Waltz Co., Ltd.) was placed on the board. The board was then placed in a nitrogen reflow oven (SNR-1065GT, manufactured by Senju Metal Industry Co., Ltd.) at 260°C to mount the chip on the board.

[0076] The solder bumped chip has a structure in which copper pillars are placed on the surface of a silicon wafer, and solder is placed on the end face of the copper pillars opposite the silicon wafer. The copper pillars and solder are collectively called solder bumps. The sizes of each component are as follows: Size of solder bumped chip: 25mm square Silicon wafer thickness: 725±25μm Solder bump pitch: 150μm Copper pillar height: 45μm Solder bump height: 15μm Solder diameter: 75μm

[0077] The flux between the solder bumped chip and the organic core material was removed using an ultrasonic cleaner (As One, VS-100III). The conditions were a frequency of 45 kHz and a cleaning time of 10 minutes. The product was then placed in an oven (Yamato Scientific, DKN402) and dried at 100°C for 30 minutes. The organic core material with the solder bumped chip mounted on it was placed on a hot plate heated to 110°C, and CUF (Capillary Underfill, Hitachi Chemical Co., Ltd., CEL-C-3730S) was injected between the organic core material and the solder bumped chip. The product was then placed in an oven and heated at 150°C for 2 hours to harden.

[0078] After the organic core material mounted with the solder bumped chip was cast in epoxy resin, the cross sections of the organic core material and the solder bumped chip were observed and the number of connections between the solder bumps and the copper foil on the surface of the organic core material was counted. The connections were checked at 10 locations on each of the solder bumps at the four corners of the solder bumped chip, for a total of 40 locations. Three specimens were used for each sample, and a total of 120 solder bumps were checked to see if they were connected to the copper foil. The percentage of connected solder bumps out of the 120 solder bumps was calculated and this was taken as the solder bump connection yield.

[0079] <Evaluation of wiring formation yield> Copper wiring was formed on the organic core material using the semi-additive process as follows. First, the copper foil of the organic core material was immersed in an ammonium persulfate solution and etched. Then, a thermosetting resin insulating build-up film (GX92, manufactured by Ajinomoto Fine-Techno Co., Ltd.) was laminated on both sides of the organic core material. A vacuum laminator (V-130, manufactured by Nikko Materials Co., Ltd.) was used. The conditions were a pressure of 0.5 MPa, a vacuum time of 15 seconds, a pressure time of 60 seconds, and a temperature of 50°C. The organic core material was then placed in an oven and heated at 130°C for 15 minutes to dry, and then heated at 190°C for 120 minutes to harden. This formed an insulating layer 15 on each side of the organic core material (Figure 5(a)).

[0080] A seed layer 16 was formed on the surface of one of the build-up film layers by sputtering (FIG. 5(b)). The seed layer 16 had a two-layer structure consisting of a 25 nm titanium layer and a 150 nm copper layer. Then, using a vacuum laminator, a photoresist film of a photosensitive resin composition (RY-5107UT, manufactured by Hitachi Chemical Co., Ltd.) was laminated onto the seed layer. The conditions were a pressure of 0.5 MPa, a vacuum time of 15 seconds, a pressure time of 60 seconds, and a temperature of 50°C. This formed a photosensitive resin layer 17 on the surface of the seed layer 16 (FIG. 5(c)).

[0081] A square area with sides of 70 mm was exposed to UV light using a projection exposure system (S6Ck exposure system, manufactured by Therma Precision Co., Ltd.). Development was then performed by spraying a 1% by mass aqueous solution of sodium carbonate using a spin developer (ultra-high pressure spin developer, manufactured by Blue Ocean Technology Co., Ltd.). This process produced a pattern with a resist width / space width of 2 μm / 2 μm (Figure 6(a)). Resist residue from development was then removed by irradiating the resist pattern with oxygen plasma using a plasma asher (AP Series batch plasma processing system, manufactured by Nordson Advanced Technology Co., Ltd.).

[0082] Wiring 18 with a wiring width / space width (L / S) of 2 μm / 2 μm was formed by electrolytic copper plating (Figure 6(b)). The wiring height was 3 μm. A 2.38 mass% aqueous solution of TMAH (tetramethylammonium hydroxide) was sprayed using a spin developer to remove the resist (Figure 6(c)). The seed layer 16 exposed by the resist removal was removed by etching (Figure 7). The copper layer was removed by immersion in an aqueous solution of copper etching solution (Mitsubishi Gas Chemical Company, WLC-C2) and pure water at a 1:1 mass ratio at 23°C for 45 seconds, followed by rinsing with pure water. The titanium layer was removed by immersion in an aqueous solution of titanium etching solution (Mitsubishi Gas Chemical Company, WLC-T) and 23% ammonia water at a 50:1 mass ratio at 23°C for 65 seconds, followed by rinsing with pure water.

[0083] Copper wiring with a wiring width / space width of 2 μm / 2 μm was observed using a metallurgical microscope, and the number of wirings without defects such as collapsed wiring, missing wiring, connections between wirings, or deformation of wiring was counted, and the percentage of such wirings out of the 45 wirings produced was calculated. This was taken as the wiring yield. The evaluation criteria were as follows: A: Wiring yield is between 75% and 100% B: Wiring yield is 50% or more but less than 75% C: Wiring yield is 0% or more but less than 50%

[0084] <Wire width measurement> The cross section of copper wiring (copper wiring: design value of line width / space width (L / S) = 5 μm / 5 μm) fabricated using the semi-additive method was observed using an SU8200 scanning electron microscope (Hitachi High-Technologies Corporation), and the wiring width was measured. The wiring width was measured at three measurement points: the center of the area that could be irradiated with UV light at one time (a square with sides of 70 mm), one of the four vertices of this square, and the vertex diagonally opposite this vertex. The standard deviation was calculated using the three measurements as the population.

[0085] <Calculating the standard deviation of thickness for a 50mm square size> We calculated the standard deviation of thickness for a laminate (see Figure 5(a)) that has an organic core material and insulating layers formed on both sides of it. A 150mm square area in the center of a 250mm square laminate (a square with sides of 250mm when viewed from above) was divided into nine 50mm square areas, and the standard deviation of the thickness of the nine areas was calculated. In the case of large packages for servers, we assumed that the chip size would be around 50mm square, so we set 50mm squares as the range for calculating the standard deviation.

[0086] Using a micrometer (Mitutoyo Corporation, ID-C112X), the thickness was measured at four points on the four corners of a 50 mm square area. The thickness values ​​at the four points were used as the population to calculate the standard deviation. The maximum value of the standard deviation calculated from the nine areas is shown in Tables 1 and 2 as the standard deviation for each laminate.

[0087] [Table 1]

[0088] [Table 2] [Industrial Applicability]

[0089] According to the present disclosure, there are provided an organic core material and a method for producing the same, a laminate including the organic core material, and a wiring board that are useful for achieving higher density and higher reliability in semiconductor packages. [Explanation of symbols]

[0090] 1...first layer, 1a...first fiber cloth, 1b...first resin layer (before curing), 1B...first resin layer (after curing), 2...second layer, 2a...second fiber cloth, 2b...second resin layer (before curing), 2B...second resin layer (after curing), 3...resin layer, 5...metal foil, 10...organic core material, 20...laminate, 10P, 20P, 30P...laminate, 15...insulating layer, 16...seed layer, 17...photosensitive resin layer, 18...wiring, 40...laminate, 50...wiring board, F1, F2...surface, P1...first prepreg, P2...second prepreg.

Claims

1. preparing a plurality of first prepregs, each having a first fiber cloth and a first resin layer made of a first resin component and having the first fiber cloth embedded therein; preparing at least two second prepregs, each having a second fiber cloth and a second resin layer made of a second resin component and having the second fiber cloth embedded therein; a step of heating a laminate including the second prepreg, a plurality of the first prepregs, and the second prepreg in this order while applying a pressing force in the thickness direction of the laminate; Including, a content of the second resin component based on the mass of the second prepreg is higher than a content of the first resin component based on the mass of the first prepreg; the content of the second resin component based on the mass of the second prepreg is 60% by mass or more, The method for producing an organic core material, wherein the first fiber cloth is a woven fabric.

2. preparing a plurality of first prepregs, each having a first fiber cloth and a first resin layer made of a first resin component and having the first fiber cloth embedded therein; preparing at least two second prepregs, each having a second fiber cloth and a second resin layer made of a second resin component and having the second fiber cloth embedded therein; a step of heating a first laminate of a plurality of the first prepregs while applying a pressing force in a thickness direction thereof; a step of heating a second laminate including the second prepreg, the first laminate, and the second prepreg in this order while applying a pressing force in a thickness direction of the second laminate; Including, a content of the second resin component based on the mass of the second prepreg is higher than a content of the first resin component based on the mass of the first prepreg; the content of the second resin component based on the mass of the second prepreg is 60% by mass or more, The method for producing an organic core material, wherein the first fiber cloth is a woven fabric.

3. The method for producing an organic core material according to claim 1 or 2, wherein the second fiber cloth is a woven fabric.

4. a first layer including a first fiber cloth and a first resin layer made of a first resin component and having the first fiber cloth embedded therein; a second layer including a second fiber cloth and a second resin layer made of a second resin component and having the second fiber cloth embedded therein; An organic core material comprising: a laminated structure including the second layer, a plurality of the first layers, and the second layer in this order; a content of the second resin component based on the mass of the second resin layer is higher than a content of the first resin component based on the mass of the first resin layer; An organic core material in which, in a longitudinal cross section of the organic core material, a second fiber cloth thinner than the first fiber cloth arranged in the center of the organic core material is arranged near the surface of the organic core material.

5. 5. The organic core material according to claim 4, wherein the standard deviation of thickness at four points corresponding to the vertices of a square with sides of 50 mm in plan view is 3.5 μm or less.

6. The organic core material according to claim 4 or 5; an insulating layer provided on the surface of the organic core material; A laminate comprising:

7. The laminate of claim 6 , wherein the insulating layer comprises a build-up layer.

8. 8. The laminate according to claim 6, wherein the standard deviation of thickness at four points corresponding to vertices of a square with sides of 50 mm in plan view is 4.0 μm or less.

9. A wiring board comprising the organic core material according to claim 4 or 5.

10. 10. The wiring board according to claim 9, comprising wiring having a width of 0.5 to 10 μm.

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