Method for manufacturing laminate

Abstract

To provide a method for manufacturing a laminate capable of manufacturing a laminate having excellent flatness of a prepreg while suppressing exposure of filaments from an end portion of the prepreg by using the prepreg including a fibrous base material with a low filament density.SOLUTION: The method for manufacturing a laminate using a two-stage laminator controls the minimum melt viscosity of a prepreg before a pressing step (II) under a reduced-pressure environment in a first stage and the minimum melt viscosity of the prepreg after the step (II) so that the minimum melt viscosity and the minimum melt viscosity satisfy predetermined requirements.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a laminate including an inner layer substrate and a prepreg, and a method for manufacturing a circuit board. [Background technology]

[0002] Circuit boards, such as semiconductor chip packages, generally have a laminated structure including an inner layer substrate and an insulating layer. For example, a circuit board may include an inner layer substrate having wiring and components inside or on its surface, and an insulating layer formed on the inner layer substrate. The insulating layer may be formed using a prepreg.

[0003] A prepreg generally comprises a fibrous base material and a resin composition impregnated into the fibrous base material. The resin composition usually contains a thermosetting resin and therefore has thermosetting properties. Therefore, by pressing the prepreg onto an inner layer substrate and thermally curing the resin composition, an insulating layer comprising the fibrous base material and a cured product of the resin composition can be formed on the inner layer substrate.

[0004] Conventionally, pressure bonding of an inner layer substrate to a prepreg has typically been performed by vacuum pressing (Patent Document 1). In vacuum pressing, the inner layer substrate and prepreg are generally placed in a cavity within a mold, the pressure inside the cavity is reduced, and the mold is then clamped. Clamping the mold forms a closed space within the cavity. In vacuum pressing, high temperature and pressure are applied to the prepreg, so the resin composition in the prepreg flows and fills the entire closed space without any gaps, and then hardens. Thus, an insulating layer containing a fiber base material and a cured product of the resin composition can be formed on the inner layer substrate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-003007 Summary of the Invention [Problem to be solved by the invention]

[0006] While conventional prepregs have typically been handled individually, the applicant has developed a resin sheet comprising a support and a prepreg disposed on the support. Using this resin sheet, it is possible to mount the prepreg on an inner layer substrate using a lamination method rather than a vacuum press. For example, a two-stage laminator with a first stage for lamination and a second stage for planarization can be used to mount the prepreg on the inner layer substrate, resulting in a laminate comprising the inner layer substrate and the prepreg. Thus, by thermally curing the prepreg in this laminate, an insulating layer can be formed on the inner layer substrate, resulting in a circuit board.

[0007] Generally, the resin composition contained in the prepreg tends to adhere to the carrier film used in the laminator. Therefore, conventional prepregs without a support have been difficult to apply to the lamination method. In contrast, by using a resin sheet with a support, lamination can be performed with the support between the prepreg and the carrier film, thereby preventing the resin composition contained in the prepreg from adhering to the carrier film and enabling the production of laminates by the lamination method. Therefore, the use of the lamination method was first realized using a resin sheet with a support. According to the lamination method using a two-stage laminator, the prepreg laminated on the inner layer substrate in the first stage can be flattened in the second stage, thereby improving the flatness of the prepreg after lamination. Therefore, an insulating layer with excellent flatness can be formed.

[0008] In recent years, the demand for smaller and thinner circuit boards has increased, leading to a demand for thinner prepregs. Therefore, the inventors attempted to reduce the number of filaments per unit dimension of the fiber substrate. In this case, the density of the filaments in the fiber substrate becomes sparse, making it possible to reduce the thickness of the prepreg.

[0009] However, when a fiber substrate with a low filament density is used, the filaments may protrude and become exposed from the edges of the prepregs contained in the laminate produced, and the exposed filaments may become foreign matter and cause a decrease in the yield of the circuit board.

[0010] The present invention has been made in view of the above-mentioned problems, and aims to provide a method for manufacturing a laminate that can manufacture a laminate having excellent flatness of the prepreg using a prepreg containing a fiber base material with a sparse filament density while suppressing exposure of the filaments from the end of the prepreg; and a method for manufacturing a circuit board that includes the manufacturing method. [Means for solving the problem]

[0011] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by appropriately controlling the minimum melt viscosity of the prepreg in each step involved in a production method using a laminator, and have thus completed the present invention. That is, the present invention includes the following.

[0012] <1> A method for producing a laminate, comprising laminating a resin sheet piece having a support and a prepreg with an inner layer substrate using a laminator; The prepreg includes a fiber substrate including a plurality of filaments and a resin composition impregnated in the fiber substrate and including a thermosetting resin; The laminator a first stage capable of laminating an inner layer substrate and a prepreg; A second stage that can flatten the prepreg; a carrier film capable of transporting the inner layer substrate and the resin sheet piece in the order of the first stage and the second stage; Equipped with; The manufacturing method comprises: a step (I) of supplying a resin sheet piece and an inner layer substrate to a first stage to obtain a state in which a carrier film, a support, a prepreg, and an inner layer substrate are stacked in this order; In a first stage, a step (II) of pressing the resin sheet piece and the inner layer substrate while applying heat in a reduced pressure environment; a step (III) of transporting the resin sheet piece and the inner layer substrate to a second stage by a transport film; In a second stage, the resin sheet piece and the inner layer substrate are pressed together while being heated to obtain a laminate (IV); a step (V) of removing the laminate from the carrier film; in this order; The fiber substrate has less than 10,000 filaments per inch in the TD direction; the ratio Y / X of the minimum melt viscosity X of the prepreg before step (II) to the minimum melt viscosity Y of the prepreg after step (II) and before step (IV) is greater than 1.2; A method for producing a laminate, wherein the minimum melt viscosity Y is less than 10,000 poise. <2> the inner layer substrate has a conductor layer exposed on a surface facing the resin sheet piece, The arithmetic mean roughness of the conductor layer is 250 nm or less. <1> A method for producing the laminate described in . <3> The resin composition includes a polymeric resin compatible with a thermosetting resin; The amount of the polymer resin is 10% by mass or less relative to 100% by mass of the resin component of the resin composition. <1> or <2> A method for producing the laminate described in . <4> The resin composition includes an inorganic filler; The amount of the inorganic filler is 50% by mass or more relative to 100% by mass of the non-volatile components of the resin composition. <1> ~ <3> 10. A method for producing the laminate according to claim 9. <5> The minimum melt viscosity X is 5,000 poise or less. <1> ~ <4> 10. A method for producing the laminate according to claim 9. <6> In step (I), the prepreg is formed over the entire MD direction of the support. <1> ~ <5> 10. A method for producing the laminate according to claim 9. <7> The method includes, prior to the step (I), a step (VI) of cutting a long resin sheet having a support and a prepreg to obtain a resin sheet piece; <1> ~ <6> 10. A method for producing the laminate according to claim 9. <8> The prepreg has a thickness of 100 μm or less. <1> ~ <7> 10. A method for producing the laminate according to claim 9. <9> <1> ~ <8> a step of producing a laminate by the production method according to any one of the above items; and curing the prepreg. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a method for producing a laminate using a prepreg containing a fiber base material with a sparse filament density, which can produce a laminate having excellent flatness of the prepreg while suppressing exposure of the filaments from the end of the prepreg; and a method for producing a circuit board including the production method. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a plan view schematically showing a resin sheet piece used in a method for producing a laminate according to one embodiment of the present invention, as viewed from the thickness direction. [Figure 2] FIG. 2 is a cross-sectional view that schematically shows a cross section of a resin sheet piece used in a method for producing a laminate according to one embodiment of the present invention. [Figure 3] FIG. 3 is an enlarged plan view schematically showing a portion indicated by reference numeral III in FIG. [Figure 4] FIG. 4 is a perspective view that schematically shows a method for producing a resin sheet piece used in a method for producing a laminate according to one embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view that schematically shows a laminator used in a method for producing a laminate according to one embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view that schematically shows how the resin sheet piece and the inner layer substrate are pressed in step (II) of the method for producing a laminate according to one embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view that schematically shows how the resin sheet piece and the inner layer substrate are pressed in step (IV) of the method for producing a laminate according to one embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional view schematically showing a laminate produced by a production method according to one embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view that schematically shows how a conventional resin sheet piece provided with a support and a prepreg is laminated with an inner layer substrate, and then pressed in a second stage to flatten the prepreg. [Figure 10] FIG. 10 is a cross-sectional view that schematically shows a laminate obtained by laminating a conventional resin sheet piece with an inner layer substrate and flattening it. [Figure 11] FIG. 11 is a schematic cross-sectional view illustrating a method for producing a laminate according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be modified and implemented within the scope of the claims and their equivalents.

[0016] In the following description, unless otherwise specified, it is preferable that there is no error in "parallel" and "perpendicular," but an error may be included. The error range is usually ±5°, preferably ±3°, more preferably ±1°, and even more preferably ±0.5°.

[0017] In the following description, the term "optionally substituted" used in reference to a compound or group means both a case where the hydrogen atoms of the compound or group are not substituted with a substituent and a case where some or all of the hydrogen atoms of the compound or group are substituted with a substituent.

[0018] <Outline of manufacturing method of laminate> A method for producing a laminate according to one embodiment of the present invention is a method for producing a laminate comprising an inner layer substrate and a prepreg by laminating a resin sheet piece comprising a support and a prepreg with an inner layer substrate using a laminator. The prepreg comprises a fibrous base material comprising a plurality of filaments (fibers) and a resin composition impregnated in the fibrous base material and comprising a thermosetting resin.

[0019] In the method for producing a laminate according to this embodiment, a laminator is used to laminate a resin sheet piece and an inner layer substrate, the laminator having a first stage capable of laminating an inner layer substrate and a prepreg, a second stage capable of flattening the prepreg, and a transport film capable of transporting the resin sheet through the first stage and then the second stage. Specifically, the method for producing a laminate according to this embodiment includes the following steps: Step (I) of feeding a resin sheet piece to a first stage; In a first stage, a step (II) of pressing the resin sheet piece and the inner layer substrate while applying heat in a reduced pressure environment; a step (III) of transporting the resin sheet piece and the inner layer substrate to a second stage by a transport film; In a second stage, the resin sheet piece and the inner layer substrate are pressed together while being heated to obtain a laminate (IV); a step (V) of removing the laminate from the carrier film; Contains, in this order:

[0020] In the manufacturing method, in step (II), a prepreg of a resin sheet piece is laminated to an inner layer substrate. Then, in step (IV), the prepreg laminated to the inner layer substrate is flattened. Therefore, a laminate comprising an inner layer substrate and a prepreg with excellent flatness can be obtained. The obtained laminate may or may not have a support.

[0021] The prepreg used in the manufacturing method according to this embodiment has a low density of filaments in the TD direction of the fiber substrate. Specifically, the number of filaments per unit dimension of the fiber substrate in the TD direction is less than a specific threshold. Unless otherwise specified, the "TD direction" refers to the direction perpendicular to the thickness direction (in-plane direction) and perpendicular to the MD direction. Furthermore, unless otherwise specified, the "MD direction" refers to the transport direction, i.e., the direction in which the transport film of the laminator travels. Therefore, the longitudinal direction of the transport film usually corresponds to the MD direction, and the width direction of the transport film corresponds to the TD direction. Resin sheet pieces containing a cross material containing warp and weft yarns as the fiber substrate are generally fed into the laminator with the warp yarns parallel to the MD direction. Therefore, when a cross material is used as the fiber substrate, the weft yarns of the fiber substrate can be parallel to the TD direction.

[0022] The prepreg used in the manufacturing method according to this embodiment has a minimum melt viscosity that satisfies certain conditions. Specifically, first, the ratio Y / X of the minimum melt viscosity X of the prepreg before step (II) to the minimum melt viscosity Y of the prepreg after step (II) but before step (IV) is greater than a certain threshold. Second, the minimum melt viscosity Y of the prepreg after step (II) but before step (IV) is less than a certain threshold.

[0023] According to the manufacturing method of this embodiment, a laminate having excellent flatness of the prepreg can be manufactured using a prepreg including a fiber base material with a sparse filament density, while suppressing exposure of the filaments from the end of the prepreg.

[0024] <Explanation of the resin sheet piece> Fig. 1 is a plan view schematically showing a resin sheet piece 10 used in a method for producing a laminate according to one embodiment of the present invention, as viewed from the thickness direction. Fig. 1 shows a state in which a portion of a prepreg 200 of the resin sheet 10 has been broken, exposing a fiber base material 210 at the broken portion. Fig. 2 is a cross-sectional view schematically showing a cross section of the resin sheet piece 10 used in a method for producing a laminate according to one embodiment of the present invention. Fig. 3 is an enlarged plan view schematically showing an enlarged portion indicated by reference symbol III in Fig. 1.

[0025] As shown in FIGS. 1 and 2, the resin sheet piece 10 used in the manufacturing method according to this embodiment includes a support 100 and a prepreg 200. Typically, the prepreg 200 is formed on one surface 100U of the support 100. The prepreg 200 may be formed on the entire surface 100U of the support 100, or may be formed on only a portion of the surface 100U. The resin sheet piece 10 can be manufactured by cutting it out from a long resin sheet (see reference numeral 20 in FIG. 4). Thus, in the longitudinal direction of the long resin sheet, the prepreg 200 can be formed on the entire support 100. Typically, the longitudinal direction of the long resin sheet is parallel to the warp threads 230 of the prepreg 200 and is also parallel to the MD direction. Therefore, the prepreg 200 is typically formed on the entire support 100 in the MD direction.

[0026] The support 100 is usually a film-like member that can support the prepreg 200. Examples of preferred support 100 include films of plastic materials and metal foils.

[0027] When a film made of a plastic material is used as the support 100, examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, with inexpensive polyethylene terephthalate being particularly preferred.

[0028] When a metal foil is used as the support 100, examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. The copper foil may be a foil made of a single metal, copper, or an alloy of copper and another metal (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

[0029] The surface 100U of the support 100 that comes into contact with the prepreg 200 may be subjected to a surface treatment such as matte treatment, corona treatment, or antistatic treatment.

[0030] The support 100 may be a support with a release layer (not shown) as the outermost layer on the side that contacts the prepreg 200. The release layer is typically formed using a release agent. Examples of the release agent include one or more types of release agents selected from the group consisting of alkyd-based release agents, polyolefin-based release agents, urethane-based release agents, and silicone-based release agents. Commercially available products may be used as the support with a release layer, including PET films with a release layer primarily composed of a silicone-based or alkyd resin-based release agent, such as "PET501010," "SK-1," "AL-5," and "AL-7" manufactured by Lintec Corporation; "Lumirror T60" manufactured by Toray Industries, Inc.; "Purex" manufactured by Teijin Limited; and "Uni-Peel" manufactured by Unitika Limited.

[0031] The thickness of the support 100 is not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, and is preferably 75 μm or less, more preferably 60 μm or less, and even more preferably 50 μm or less. When a support with a release layer is used, it is preferable that the thickness of the entire support with a release layer is within the above range.

[0032] As shown in FIG. 2, the prepreg 200 includes a fiber base material 210 and a resin composition 220 impregnated into the fiber base material 210.

[0033] The fiber substrate 210 includes a plurality of filaments 231 and 241. Gaps are formed between the filaments 231 and 241, and the resin composition 220 impregnated into the fiber substrate 210 can be held in these gaps. The resin composition 220 may be held not only in the gaps between the filaments 231 and 241 of the fiber substrate 210, but also around the filaments 231 and 241. The fiber substrate 210 may be, for example, a nonwoven fabric. The fiber substrate 210 may also include yarns 231 and 241 formed by bundling a plurality of filaments 231 and 241. As a specific example, the fiber substrate 210 may be a cross material woven with warp threads 230 and weft threads 240. In this embodiment, a cross material including a plurality of warp threads 230 and a plurality of weft threads 240 will be described as an example, as shown in FIG. 3 .

[0034] The warp yarns 230 are yarns formed by bundling a plurality of filaments 231, and therefore contain a plurality of filaments 231. The weft yarns 240 are yarns formed by bundling a plurality of filaments 241, and therefore contain a plurality of filaments 241. As shown in Fig. 3, the fiber base material 210 is formed by weaving the warp yarns 230 and the weft yarns 240. Therefore, when viewed from the thickness direction, the warp yarns 230 and the weft yarns 240 are arranged to intersect perpendicularly.

[0035] The number of filaments in the fiber base material 210 per inch in the TD direction is typically less than 10,000, more preferably 9,500 or less, even more preferably 9,000 or less, and may be 8,000 or less, 7,000 or less, or 6,000 or less. The lower limit is preferably 1,000 or more, more preferably 2,000 or more, and even more preferably 3,000 or more. When the number of filaments is small, the gaps between the filaments can be increased, allowing for smooth air release during impregnation with the resin composition. This can suppress the formation of voids (air bubbles) in the prepreg 200. Furthermore, the fiber base material 210 can be made thinner, allowing for a thinner prepreg 200, and therefore a thinner insulating layer formed by curing the prepreg 200. When the number of filaments is less than the upper limit of the above range, the filament density becomes sparse, weakening the binding between the filaments. Therefore, in the past, filaments could be exposed from the edges of the laminate obtained after lamination. However, according to the manufacturing method of this embodiment, it is possible to manufacture a laminate while suppressing such filament exposure. Furthermore, when the number of filaments is equal to or greater than the lower limit of the above range, the mechanical strength of the fiber base material 210 can be increased, thereby improving the mechanical strength of the insulating layer.

[0036] The number of filaments of the fiber substrate 210 per inch in the TD direction refers to the number of filaments that are not parallel to the TD direction per inch of the fiber substrate 210 in the TD direction. When a cross material including warp yarns 230 and weft yarns 240 is used for the fiber substrate 210 as in the example shown in this embodiment, the warp yarns 230 are typically parallel to the MD direction, and the weft yarns 240 are typically parallel to the TD direction. Therefore, the number of filaments 231 contained in the warp yarns 230 per inch in the TD direction can represent the "number of filaments of the fiber substrate 210 per inch in the TD direction." Generally, the number of filaments 231 contained in threads such as the warp yarns 230 and the weft yarns 240 is constant. Therefore, the "number of filaments of the fiber substrate 210 per inch in the TD direction" can be calculated by multiplying the number of filaments 231 contained in one warp yarn 230 by the number of warp yarns 230 per inch in the TD direction.

[0037] The number of filaments contained in one yarn, such as the warp yarn 230 or the weft yarn 240, is sometimes referred to as the "number of bundled filaments." The range of the number of bundled filaments is preferably 20 or more, more preferably 30 or more, even more preferably 40 or more, and preferably 120 or less, more preferably 110 or less, and even more preferably 100 or less. The number of bundled filaments of the warp yarn 230 and the number of peripheral filaments of the weft yarn 240 may be the same or different. When the number of bundled filaments is within the above range, the effects of the present invention can be significantly achieved.

[0038] The number of threads per unit dimension contained in the fiber substrate 210 is preferably 50 threads / 25 mm or more, more preferably 55 threads / 25 mm or more, even more preferably 60 threads / 25 mm or more, even more preferably 70 threads / 25 mm or more, and preferably 150 threads / 25 mm or less, more preferably 130 threads / 25 mm or less, and even more preferably 120 threads / 25 mm or less. The "number of threads per unit dimension" refers to the number of threads per unit dimension in the in-plane direction perpendicular to the direction in which the threads extend. Thus, for example, the number of warp threads 230 per unit dimension refers to the number of warp threads 230 per unit dimension in the in-plane direction (usually the TD direction) perpendicular to the direction in which the warp threads 230 extend. Hereinafter, the number of warp threads 230 per unit dimension may be referred to as the "warp density." Furthermore, the number of weft threads 240 per unit dimension may be referred to as the "weft density." The warp density and weft density may be the same or different. When the number of threads per unit dimension is within the above range, the effects of the present invention can be significantly obtained.

[0039] The material of the filaments 231 and 241 can be an insulating material, preferably a material with a small dielectric tangent. Preferred examples of the material of the filaments 231 and 241 include glass materials and resin materials such as aramid resin and liquid crystal polymer. Among these, glass materials are preferred. When a glass material is used, the fiber substrate 210 may be a glass cloth, and the filaments 231 and 241 may be glass filaments.

[0040] The fiber substrate 210 may be surface-treated with a surface treatment agent. By performing the surface treatment, the formation of voids in the prepreg 200 can be suppressed. Examples of the surface treatment agent include coupling agents such as silane coupling agents and titanate coupling agents; and silane compounds such as alkoxysilanes and organosilazane compounds. Of these, coupling agents are preferred, and silane coupling agents are more preferred. Examples of the silane coupling agent include aminosilane coupling agents, fluorine-containing silane coupling agents, epoxysilane coupling agents, and mercaptosilane coupling agents. Aminosilane coupling agents are more preferred. One type of surface treatment agent may be used alone, or two or more types may be used in combination.

[0041] Commercially available surface treatment agents may be used. Examples of commercially available surface treatment agents include Shin-Etsu Chemical Co., Ltd.'s "KBM403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM803" (3-mercaptopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent), and Shin-Etsu Chemical Co., Ltd.'s "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane).

[0042] The degree of surface treatment with the surface treatment agent preferably falls within a specific range from the viewpoint of smooth impregnation of the resin composition and suppressing void formation. Specifically, 100% by mass of the fiber substrate is preferably surface-treated with 0.01% to 5% by mass of the surface treatment agent, more preferably 0.1% to 4% by mass of the surface treatment agent, and even more preferably 0.2% to 3.5% by mass of the surface treatment agent. The surface treatment of the fiber substrate 210 may be performed, for example, by the method described in Japanese Patent No. 7183344.

[0043] The mass per unit area of ​​the fiber substrate 210 may be referred to as the "fabric mass." The fabric mass of the fiber substrate 210 is preferably in the range of 5 g / m 2 More preferably, 10 g / m 2 More preferably, 15 g / m 2 or more, preferably 50 g / m 2 Less than 40 g / m 2 More preferably 30 g / m or less 2 When the fabric mass is within the above range, the effects of the present invention can be significantly obtained.

[0044] A commercially available product may be used as the fiber base material 210. Examples of commercially available fiber base materials 210 include glass cloths manufactured by Nitto Boseki Co., Ltd., such as "Style WEA1017," "Style WEA1024," "Style WEA1010," "Style WEA1027," "Style WEA1035," and "Style WEA1037."

[0045] The fiber substrate 210 is preferably thin. The specific thickness of the fiber substrate 210 is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 30 μm or less, and even more preferably 20 μm or less. The lower limit can be, for example, 5 μm or more, 10 μm or more, or 15 μm or more.

[0046] The resin composition 220 is a composition containing a thermosetting resin, and is impregnated into the above-described fiber substrate 210. Typically, thermosetting resins react with heat to form bonds. Therefore, when heat is applied, the minimum melt viscosity of the resin composition 220 increases, and therefore the minimum melt viscosity of the prepreg 200 containing the resin composition 220 also increases. In this embodiment, the degree of increase in the minimum melt viscosity of the prepreg 200 caused by the heat during lamination in step (II) is greater than a specific threshold, and the minimum melt viscosity of the prepreg 200 after lamination is less than a specific threshold.

[0047] The degree of increase in the minimum melt viscosity of the prepreg 200 caused by the heat during lamination in step (II) is represented by the viscosity ratio Y / X. Viscosity X represents the minimum melt viscosity of the prepreg 200 before step (II). Viscosity Y represents the minimum melt viscosity of the prepreg after step (II) but before step (IV). The viscosity ratio Y / X is typically greater than 1.20, more preferably 1.21 or greater, and even more preferably 1.22 or greater. The upper limit is preferably 20 or less, more preferably 15 or less, even more preferably 10 or less, and particularly preferably 2.0 or less. When the viscosity ratio Y / X is within the above range, it is possible to produce a laminate having excellent flatness of the prepreg 200 while suppressing exposure of the filaments 231 from the ends of the prepreg 200.

[0048] The minimum melt viscosity of the prepreg 200 after lamination in step (II) is represented by the minimum melt viscosity Y of the prepreg after step (II) and before step (IV). The range of the minimum melt viscosity Y is usually less than 10,000 poise, more preferably 9,000 poise or less, even more preferably 8,000 poise or less, even more preferably 6,000 poise or less, and particularly preferably 4,000 poise or less. The lower limit is preferably 300 poise or more, more preferably 500 poise or more, and even more preferably 700 poise or more. When the minimum melt viscosity Y is within the above range, it is possible to produce a laminate having excellent flatness of the prepreg 200 while suppressing exposure of the filaments 231 from the end of the prepreg 200.

[0049] The minimum melt viscosity X of the prepreg 200 before step (II) is preferably 200 poise or more, more preferably 400 poise or more, even more preferably 600 poise or more, and preferably 7,000 poise or less, more preferably 6,000 poise or less, and even more preferably 5,000 poise or less. When the minimum melt viscosity X is at least the lower limit of the above range, excessive flow of the resin composition in step (II) can be suppressed, thereby suppressing excessive outflow of the resin composition to areas not covered by the support. When the minimum melt viscosity X is at most the upper limit of the above range, the fluidity of the resin composition in step (II) can be increased, allowing for good embedding of wiring and components on the inner layer substrate, thereby suppressing the formation of voids in the prepreg of the laminate.

[0050] The minimum melt viscosities X and Y of the prepreg 200 can be measured by stacking 20 sheets of the prepreg to prepare a measurement sample, and then using a dynamic viscoelasticity measuring device to measure the measurement sample. The measurement can be performed by increasing the temperature from a starting temperature of 60°C to 200°C and measuring the dynamic viscoelasticity of the measurement sample. The measurement conditions can be a temperature increase rate of 5°C / min, a measurement temperature interval of 2.5°C, a vibration frequency of 1 Hz, and a strain of 1 deg. Specific measurement methods may be as described in the examples below.

[0051] The composition of the resin composition 220 is preferably adjusted so that the minimum melt viscosities X and Y satisfy the above-mentioned requirements. For example, the lower the melt viscosity of the resin component in the resin composition, the lower the minimum melt viscosity X before lamination, and therefore the lower the minimum melt viscosity Y after lamination. Furthermore, for example, the higher the compatibility of the resin components in the resin composition, the lower the minimum melt viscosity X before lamination, and therefore the lower the minimum melt viscosity Y after lamination. Furthermore, for example, when the resin composition contains particles such as an inorganic filler, the larger the particles, the lower the minimum melt viscosity X before lamination, and therefore the lower the minimum melt viscosity Y after lamination. Furthermore, for example, the greater the amount of catalyst such as a curing accelerator, the greater the viscosity of the prepreg 200 in step (II), and therefore the larger the viscosity ratio Y / X. Furthermore, for example, the smaller the active group equivalent of the thermosetting resin, the greater the viscosity of the prepreg 200 in step (II), and therefore the larger the viscosity ratio Y / X. Furthermore, for example, the greater the amount of thermosetting resin that can react at the lamination temperature in step (II), the greater the viscosity of prepreg 200 in step (II), and therefore the greater the viscosity ratio Y / X tends to be.

[0052] Below, an example of the composition of the resin composition 220 will be described. However, the values ​​of the minimum melt viscosities X and Y can vary depending not only on the composition of the resin composition 220 but also on the amount of the resin composition in the prepreg 200 and the lamination conditions in step (II). Therefore, it is preferable that the specific composition of the resin composition 220 is set based on the above circumstances and on factors such as the amount of the resin composition and the lamination conditions so that the desired minimum melt viscosities X and Y are obtained.

[0053] The resin composition 220 includes (A) a thermosetting resin. Generally, the (A) thermosetting resin undergoes a reaction during lamination in step (II) to form bonds, thereby increasing the melt viscosity of the resin composition 220. Examples of the (A) thermosetting resin include epoxy resins, active ester resins, phenolic resins, cyanate ester resins, carbodiimide resins, acid anhydride resins, amine resins, benzoxazine resins, thiol resins, and radically polymerizable resins. One type of (A) thermosetting resin may be used alone, or two or more types may be used in combination.

[0054] The (A) thermosetting resin preferably contains an epoxy resin, which may be a curable resin having an epoxy group. Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AF type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol novolac type epoxy resins, phenol novolac type epoxy resins, tert-butyl-catechol type epoxy resins, naphthalene type epoxy resins, naphthol type epoxy resins, anthracene type epoxy resins, glycidylamine type epoxy resins, glycidyl ester type epoxy resins, cresol novolac type epoxy resins, phenol aralkyl type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, naphthylene ether type epoxy resins, trimethylol type epoxy resins, tetraphenylethane type epoxy resins, isocyanurate type epoxy resins, and phenolphthalimidine type epoxy resins. Biphenyl-type epoxy resin refers to an epoxy resin having a biphenyl structure, where the biphenyl structure may have a substituent such as an alkyl group, an alkoxy group, an aryl group, etc. Therefore, bixylenol-type epoxy resins and biphenylaralkyl-type epoxy resins may also be included in the biphenyl-type epoxy resins.

[0055] From the viewpoint of obtaining a cured product having excellent heat resistance, the epoxy resin preferably contains an epoxy resin containing an aromatic structure. The aromatic structure is a chemical structure generally defined as aromatic, and also includes polycyclic aromatic rings and aromatic heterocycles. Examples of epoxy resins containing an aromatic structure include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AF type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol novolac type epoxy resins, phenol novolac type epoxy resins, tert-butyl-catechol type epoxy resins, naphthalene type epoxy resins, naphthol type epoxy resins, anthracene type epoxy resins, bisxyleneol type epoxy resins, glycidylamine type epoxy resins having an aromatic structure, glycidyl ester type epoxy resins having an aromatic structure, cresol novolac type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins having an aromatic structure, epoxy resins having a butadiene structure having an aromatic structure, alicyclic epoxy resins having an aromatic structure, heterocyclic epoxy resins, spiro ring-containing epoxy resins having an aromatic structure, cyclohexanedimethanol type epoxy resins having an aromatic structure, naphthylene ether type epoxy resins, trimethylol type epoxy resins having an aromatic structure, and tetraphenylethane type epoxy resins having an aromatic structure.

[0056] Among these, bisphenol A type epoxy resins, bisphenol type epoxy resins, naphthalene type epoxy resins, and biphenyl type epoxy resins are preferred; bisphenol A type epoxy resins, bisphenol type epoxy resins, naphthalene type epoxy resins, bixylenol type epoxy resins, and biphenyl aralkyl type epoxy resins are more preferred.

[0057] The epoxy resin preferably contains an epoxy resin having two or more epoxy groups in one molecule, and the proportion of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, relative to 100% by mass of the non-volatile components of the epoxy resin.

[0058] Epoxy resins include those that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and those that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). As the epoxy resin, only liquid epoxy resins may be used, only solid epoxy resins may be used, or a combination of liquid epoxy resins and solid epoxy resins may be used.

[0059] The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups per molecule, such as bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol AF epoxy resin, naphthalene epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, phenol novolac epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane epoxy resin, cyclohexanedimethanol epoxy resin, and epoxy resin having a butadiene structure; more preferably bisphenol A epoxy resin and naphthalene epoxy resin.

[0060] Specific examples of liquid epoxy resins include "HP-4032," "HP-4032-D," and "HP-4032-SS" (naphthalene-type epoxy resins) manufactured by DIC Corporation; "828US," "828EL," "jER828EL," "825," and "Epikote 828EL" (bisphenol A-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER807" and "1750" (bisphenol F-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolac-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630," "630LSD," and "604" (glycidylamine-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "ED-523T" (glycirol-type epoxy resin) manufactured by ADEKA Corporation; and "EP-3950L" and "EP-398" manufactured by ADEKA Corporation. 0S" (glycidylamine type epoxy resin); ADEKA's "EP-4088S" (dicyclopentadiene type epoxy resin); Nippon Steel Chemical & Material's "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin); Nagase ChemteX's "EX-721" (glycidyl ester type epoxy resin); Daicel's "Celloxide 2021P" (alicyclic epoxy resin with an ester skeleton); Daicel's "PB-3600," Nippon Soda's "JP-100" and "JP-200" (epoxy resins with a butadiene structure); and Nippon Steel Chemical & Material's "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin).

[0061] The solid epoxy resin is preferably a solid epoxy resin having three or more epoxy groups per molecule, more preferably an aromatic solid epoxy resin having three or more epoxy groups per molecule.The solid epoxy resin is preferably a bixylenol epoxy resin, a naphthalene epoxy resin, a naphthalene tetrafunctional epoxy resin, a naphthol novolac epoxy resin, a cresol novolac epoxy resin, a dicyclopentadiene epoxy resin, a trisphenol epoxy resin, a naphthol epoxy resin, a biphenyl epoxy resin, a naphthylene ether epoxy resin, an anthracene epoxy resin, a bisphenol A epoxy resin, a bisphenol AF epoxy resin, a phenol aralkyl epoxy resin, a tetraphenylethane epoxy resin, or a phenolphthalimidine epoxy resin; more preferably a bixylenol epoxy resin, a biphenyl epoxy resin, or a naphthylene ether epoxy resin.

[0062] Specific examples of solid epoxy resins include DIC Corporation's "HP4032H" (naphthalene-type epoxy resin); DIC Corporation's "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resins); DIC Corporation's "N-690" (cresol novolac-type epoxy resin); DIC Corporation's "N-695" (cresol novolac-type epoxy resin); DIC Corporation's "HP-7200," "HP-7200HH," "HP-7200H," and "HP-7200L" (dicyclopentadiene-type epoxy resins); and DIC Corporation's "EXA-7311." "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin); "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "ESN475V", "ESN4" manufactured by Nippon Steel Chemical & Material Co., Ltd. 100V" (naphthalene-type epoxy resin); "ESN485" (naphthol-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN375" (dihydroxynaphthalene-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YX4000HK", and "YL7890" (bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL6121" (biphenyl-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "Y" manufactured by Mitsubishi Chemical Corporation Examples include "X7700" (phenol aralkyl type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals Co., Ltd.; "YX7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation; and "WHR991S" (phenolphthalimidine type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.

[0063] When the (A) thermosetting resin contains a combination of a liquid epoxy resin and a solid epoxy resin, the mass ratio thereof (liquid epoxy resin:solid epoxy resin) is preferably 20:1 to 1:20, more preferably 10:1 to 1:10, and even more preferably 7:1 to 1:7.

[0064] The epoxy equivalent of the epoxy resin is preferably in the range of 50 g / eq to 5,000 g / eq, more preferably 60 g / eq to 3,000 g / eq, even more preferably 80 g / eq to 2,000 g / eq, and particularly preferably 110 g / eq to 1,000 g / eq. The epoxy equivalent represents the mass of the resin per equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0065] The weight average molecular weight (Mw) of the epoxy resin is preferably in the range of 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight average molecular weight can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

[0066] The amount of epoxy resin is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, and is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, relative to 100% by mass of the nonvolatile components in the resin composition. Unless otherwise specified, the nonvolatile components in the resin composition refer to the components excluding the solvent in the resin composition.

[0067] The amount of the epoxy resin is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. Unless otherwise specified, the resin components in the resin composition refer to the non-volatile components in the resin composition excluding the inorganic filler (C) described below.

[0068] The (A) thermosetting resin preferably contains a combination of an epoxy resin and a resin capable of reacting with and bonding to the epoxy resin to cure the resin composition. Hereinafter, the resin capable of reacting with and bonding to the epoxy resin to cure the resin composition may be referred to as a "curing agent." The term "curing agent" does not include the above-mentioned epoxy resins. Examples of curing agents include phenolic resins, active ester resins, carbodiimide resins, cyanate resins, benzoxazine resins, acid anhydride resins, amine resins, and thiol resins. Among these, phenolic resins and active ester resins are preferred.

[0069] As the phenolic resin, a resin having one or more, preferably two or more, hydroxyl groups (phenolic hydroxyl groups) bonded to an aromatic ring such as a benzene ring or a naphthalene ring per molecule can be used. From the viewpoint of heat resistance and water resistance, a phenolic resin having a novolac structure is preferred. From the viewpoint of adhesion, a nitrogen-containing phenolic resin is preferred, and a triazine skeleton-containing phenolic resin is more preferred. Among these, a triazine skeleton-containing phenolic novolac resin is preferred from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion.

[0070] Specific examples of phenolic resins include "MEH-7700," "MEH-7810," "MEH-7851," and "MEH-8000H" manufactured by Meiwa Kasei Co., Ltd.; "NHN," "CBN," and "GPH" manufactured by Nippon Kayaku Co., Ltd.; and "SN-170," "SN-180," "SN-190," "SN-475," "SN-485," "SN-485-60M," "SN-495," and "SN-495V" manufactured by Nippon Steel Chemical & Material Co., Ltd. "," "SN-375," and "SN-395" manufactured by DIC Corporation; "TD-2090," "TD-2090-60M," "LA-7052," "LA-7054," "LA-1356," "LA-3018," "LA-3018-50P," "LA-1356," "TD2090," and "TD-2090-60M" manufactured by Gun-ei Chemical Co., Ltd.; and "GDP-6115L," "GDP-6115H," and "ELPC75" manufactured by Gun-ei Chemical Co., Ltd.

[0071] The amount of the phenolic resin is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, relative to 100% by mass of the non-volatile components in the resin composition, and is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less.

[0072] The amount of the phenolic resin is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, and even more preferably 2.0% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 70% by mass or less, more preferably 50% by mass or less, and even more preferably 30% by mass or less.

[0073] The active ester resin may be a resin having one or more, preferably two or more, active ester groups in one molecule. Among them, preferred active ester resins are those having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds.

[0074] The active ester resin is preferably one obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. From the viewpoint of improving heat resistance in particular, an active ester resin obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester resin obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferred. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalene, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolak. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by condensing one dicyclopentadiene molecule with two phenol molecules.

[0075] Specifically, the active ester resin is preferably a dicyclopentadiene-type active ester resin, a naphthalene-type active ester resin containing a naphthalene structure, an active ester resin containing an acetylated product of phenol novolac, or an active ester resin containing a benzoylated product of phenol novolac, and among these, a naphthalene-type active ester resin is more preferred. The dicyclopentadiene-type active ester resin is preferably an active ester resin containing a dicyclopentadiene-type diphenol structure.

[0076] Commercially available active ester resins include, for example, "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", "EXB-8000L-65M", "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000", "HPC-8000-65T", "HPC-8000H", and "HPC-8000H-65TM" (manufactured by DIC Corporation) as active ester resins containing a dicyclopentadiene-type diphenol structure; and "HP-B-8151-62T", "EXB-8100L-65T", "EXB-8150-60T", and "EXB-8150-62" as active ester resins containing a naphthalene structure. Examples of such active ester resins include "EXB9401" (manufactured by DIC Corporation), "EXB-9416-70BK", "HPC-8150-60T", "HPC-8150-62T", and "HPC-8151-62T" (manufactured by DIC Corporation), a phosphorus-containing active ester resin, "EXB9401" (manufactured by DIC Corporation), "DC808" (manufactured by Mitsubishi Chemical Corporation), an active ester resin which is an acetylated product of phenol novolac, "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation), and an active ester resin containing a styryl group and a naphthalene structure, "PC1300-02-65MA" (manufactured by Air Water Inc.).

[0077] The range of the amount of the active ester resin is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, and even more preferably 5.0% by mass or more, relative to 100% by mass of the non-volatile components in the resin composition, and is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0078] The range of the amount of the active ester resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0079] As the carbodiimide resin, a resin having one or more, preferably two or more, carbodiimide structures in one molecule can be used. Specific examples of the carbodiimide resin include aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexanebis(methylene-t-butylcarbodiimide); aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylenebiscyclohexylenecarbodiimide), and poly(isophoronecarbodiimide); poly(phenylenecarbodiimide), poly(naphthalenecarbodiimide); Examples of polycarbodiimides include aromatic polycarbodiimides such as poly(methylenediphenylenecarbodiimide), poly(tolylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylenediphenylenecarbodiimide), and poly[methylenebis(methylphenylene)carbodiimide]. Commercially available carbodiimide resins include, for example, "Carbodilite V-02B," "Carbodilite V-03," "Carbodilite V-04K," "Carbodilite V-05," "Carbodilite V-07," and "Carbodilite V-09" manufactured by Nisshinbo Chemical Inc.; and "Stavaxol P," "Stavaxol P400," and "Hykasil 510" manufactured by Lanxess AG.

[0080] As the cyanate-based resin, a resin having one or more, preferably two or more, cyanate groups in one molecule can be used. Examples of cyanate resins include bifunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, and bis(4-cyanatephenyl)ether; multifunctional cyanate resins derived from phenol novolac, cresol novolac, and the like; and prepolymers in which these cyanate resins are partially triazine converted. Specific examples of cyanate-based resins include "PT30" and "PT60" (phenol novolac-type multifunctional cyanate-based resins) manufactured by Arxada, "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate has been triazine-converted to form a trimer).

[0081] The benzoxazine resin may be a resin having one or more, preferably two or more, benzoxazine rings in one molecule. Specific examples of the benzoxazine resin include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Corporation, "HFB2006M" manufactured by Showa Polymer Co., Ltd., and "Pd", "Fa", and "ALP-d" manufactured by Shikoku Chemicals Corporation.

[0082] As the acid anhydride resin, a resin having one or more, preferably two or more, acid anhydride groups in one molecule can be used. Specific examples of the acid anhydride resin include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic dianhydride. Examples of suitable anhydrides include anhydrides, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymeric anhydrides such as styrene-maleic acid resins, which are copolymers of styrene and maleic acid. Commercially available acid anhydride resins include, for example, "HNA-100," "MH-700," "MTA-15," "DDSA," and "OSA" manufactured by New Japan Chemical Co., Ltd.; "YH-306" and "YH-307" manufactured by Mitsubishi Chemical Corporation; "HN-2200" manufactured by Resonac Corporation; and "EF-30," "EF-40," "EF-60," and "EF-80" manufactured by Cray Valley Chemical Industries, Ltd.

[0083] The amine resin may be a resin having one or more, preferably two or more, amino groups in one molecule. Examples of the amine resin include aliphatic amines, polyether amines, alicyclic amines, and aromatic amines, with aromatic amines being preferred. The amine resin is preferably a primary amine or secondary amine, with primary amines being more preferred. Specific examples of the amine resin include 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, and 2,2-bis(3-amino-4-hydroxyphenyl)propanol. Examples of suitable bis(4-aminophenoxy)benzene include bis(4-aminophenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, and bis(4-(3-aminophenoxy)phenyl)sulfone. Commercially available amine-based resins include, for example, "SEIKACURE-S" manufactured by Seika Corporation; "KAYABOND C-200S," "KAYABOND C-100," "KAYAHARD AA," "KAYAHARD AB," and "KAYAHARD AS" manufactured by Nippon Kayaku Co., Ltd.; "Epicure W" manufactured by Mitsubishi Chemical Corporation; and "DTDA" manufactured by Sumitomo Seika Chemicals Co., Ltd.

[0084] Examples of thiol-based resins include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris(3-mercaptopropyl)isocyanurate.

[0085] The active group equivalent of the curing agent is preferably in the range of 50 g / eq to 3,000 g / eq, more preferably 100 g / eq to 1,000 g / eq, even more preferably 100 g / eq to 500 g / eq, and particularly preferably 100 g / eq to 300 g / eq. The active group equivalent represents the mass of the resin per equivalent of the active group. For example, the active group equivalent of a phenolic resin represents the phenolic hydroxyl group equivalent, which represents the mass of the resin per equivalent of the phenolic hydroxyl group.

[0086] The weight average molecular weight (Mw) range of the curing agent may be the same as the weight average molecular weight (Mw) range of the epoxy resin.

[0087] The number of active groups in the curing agent is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, and preferably 5 or less, more preferably 3 or less, even more preferably 2 or less, assuming that the number of epoxy groups in the epoxy resin is 1. The "number of epoxy groups in the epoxy resin" in a resin composition refers to the total value obtained by dividing the mass of the non-volatile components of the epoxy resins present in the resin composition by their epoxy equivalents. Furthermore, the "number of active groups in the curing agent" refers to the total value obtained by dividing the mass of the non-volatile components of the curing agent present in the resin composition by their active group equivalents.

[0088] The amount of the curing agent is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, relative to 100% by mass of the non-volatile components in the resin composition, and is preferably 60% by mass or less, more preferably 40% by mass or less, and particularly preferably 20% by mass or less.

[0089] The amount of the curing agent is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, relative to 100% by mass of the resin component in the resin composition, and is preferably 70% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less.

[0090] The (A) thermosetting resin may contain a radically polymerizable resin. Typically, a resin containing a non-aromatic carbon-carbon unsaturated bond can be used as the radically polymerizable resin. Therefore, the radically polymerizable resin may have a radically polymerizable group containing a non-aromatic carbon-carbon unsaturated bond. Examples of the radically polymerizable group include unsaturated hydrocarbon groups such as vinyl, allyl, 1-propenyl, 3-cyclohexenyl, 3-cyclopentenyl, 2-vinylphenyl, 3-vinylphenyl, and 4-vinylphenyl; and α,β-unsaturated carbonyl groups such as acryloyl, methacryloyl, and maleimide groups (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl). Preferred radically polymerizable resins include (meth)acrylic radically polymerizable resins, styrene radically polymerizable resins, allyl radically polymerizable resins, and maleimide radically polymerizable resins.

[0091] The amount of the (A) thermosetting resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 90% by mass or less, more preferably 70% by mass or less, and even more preferably 50% by mass or less.

[0092] The amount of (A) thermosetting resin is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is usually 100% by mass or less, preferably 95% by mass or less, and more preferably 90% by mass or less.

[0093] The resin composition may contain a (B) polymer resin as an optional component. The (B) polymer resin usually has thermoplastic properties. The (B) polymer resin is usually contained in the resin composition in a state where it is compatible with the (A) thermosetting resin, and is contained in the cured product in this compatible state. The (B) polymer resin usually increases the melt viscosity of the resin composition. The (B) polymer resin does not include those corresponding to the above-mentioned component (A). The (B) polymer resin may be used alone or in combination of two or more types.

[0094] The (B) polymer resin usually has a large molecular weight. Specifically, the weight-average molecular weight Mw of the (B) polymer resin is preferably greater than 5,000, more preferably 8,000 or more, even more preferably 10,000 or more, even more preferably 20,000 or more, and is preferably 100,000 or less, more preferably 70,000 or less, even more preferably 60,000 or less, even more preferably 50,000 or less. The weight-average molecular weight Mw can be measured by gel permeation chromatography (GPC) in terms of polystyrene.

[0095] Examples of (B) polymer resins include phenoxy resins, polyimide resins, polyvinyl acetal resins, polystyrene resins, polyolefin resins, polybutadiene resins, polyamideimide resins, polyethersulfone resins, polysulfone resins, polyetherimide resins, polyphenylene ether resins, polycarbonate resins, polyetheretherketone resins, polyester resins, etc. Among these, phenoxy resins are preferred.

[0096] Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A, bisphenol F, bisphenol S, bisphenolacetophenone, novolac, biphenyl, fluorene, dicyclopentadiene, norbornene, naphthalene, anthracene, adamantane, terpene, and trimethylcyclohexane. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Specific examples of phenoxy resins include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both of which are phenoxy resins containing a bisphenol A skeleton); "YX8100" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol S skeleton); "YX6954" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol acetophenone skeleton); "FX280" and "FX293" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YL7500BH30," "YX6954BH30," "YX7553," "YX7553BH30," "YL7769BH30," "YL6794," "YL7213," "YL7290," "YL7482," and "YL7891BH30" manufactured by Mitsubishi Chemical Corporation; and the like.

[0097] Specific examples of polyimide resins include "PIAD200" manufactured by Arakawa Chemical Industry Co., Ltd., "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., and "Rikacoat SN20" and "Rikacoat PN20" manufactured by New Japan Chemical Co., Ltd. Specific examples of polyimide resins also include modified polyimide resins such as linear polyimide resins obtained by reacting bifunctional hydroxyl group-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride (polyimide resins described in JP-A No. 2006-37083), and polysiloxane skeleton-containing polyimide resins (polyimide resins described in JP-A Nos. 2002-12667 and 2000-319386).

[0098] Examples of polyvinyl acetal resins include polyvinyl formal resins and polyvinyl butyral resins, with polyvinyl butyral resins being preferred. Specific examples of polyvinyl acetal resins include S-LEC BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, and BM series manufactured by Sekisui Chemical Co., Ltd.

[0099] Examples of polystyrene resins include unmodified polystyrene resins, oxazoline group-containing modified polystyrene resins, and styrene block copolymers. Examples of styrene block copolymers include styrene-isoprene-styrene block copolymers (SIS resins), styrene-ethylene-butylene-styrene block copolymers (SEBS resins), styrene-ethylene-propylene-styrene block copolymers (SEPS resins), styrene-butadiene-styrene block copolymers (SBS resins), and styrene-isobutylene-styrene block copolymers (SIBS resins). Specific examples of polystyrene resins include "PX3-RP-37" and "RP-RX-61" (oxazoline group-containing modified polystyrene resins) manufactured by Nippon Shokubai; and "HYBRAR" manufactured by Kuraray Co., Ltd. 5125 (SIS resin); Asahi Kasei Corporation's "S1611" (SEBS resin); Asahi Kasei Corporation's "H1041", "Tuftec H1043", "Tuftec P2000", and "Tuftec MP10" (hydrogenated styrene-based thermoplastic resins); Daicel Corporation's "Epofriend AT501" and "CT310" (epoxidized styrene-butadiene thermoplastic resins); Kuraray Corporation's "Septon HG252" (modified polystyrene resin with hydroxyl groups); Asahi Kasei Corporation's "Tuftec N503M" (modified polystyrene resin with carboxyl groups); Asahi Kasei Corporation's "Tuftec N501" (modified polystyrene resin with amino groups); Asahi Kasei Corporation's "Tuftec M1913" (modified polystyrene resin with acid anhydride groups); Kuraray Corporation's "Septon S8104" (unmodified polystyrene resin); Kraton Corporation's "FG1924" (styrene-ethylene / butylene-styrene block copolymer); and "EF-40" (CRAY (manufactured by VALLEY Co., Ltd.)

[0100] Examples of polyolefin resins include ethylene copolymer resins such as low-density polyethylene, very low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer; and polyolefin polymers such as polypropylene and ethylene-propylene block copolymer.

[0101] Examples of polybutadiene resins include hydrogenated polybutadiene skeleton-containing resins, hydroxy group-containing polybutadiene resins, phenolic hydroxy group-containing polybutadiene resins, carboxy group-containing polybutadiene resins, acid anhydride group-containing polybutadiene resins, epoxy group-containing polybutadiene resins, isocyanate group-containing polybutadiene resins, urethane group-containing polybutadiene resins, and polyphenylene ether-polybutadiene resins.

[0102] Specific examples of polyamide-imide resins include "Vylomax HR11NN" and "Vylomax HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of polyamide-imide resins also include modified polyamide-imides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamide-imides) manufactured by Hitachi Chemical Co., Ltd.

[0103] A specific example of the polyethersulfone resin is "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

[0104] Specific examples of polysulfone resins include polysulfones "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

[0105] The polyphenylene ether resin may be, for example, a copolymer of polyphenylene ether and polybutadiene.

[0106] A specific example of the polyetherimide resin is "Ultem" manufactured by GE.

[0107] Examples of polycarbonate resins include hydroxy group-containing carbonate resins, phenolic hydroxy group-containing carbonate resins, carboxy group-containing carbonate resins, acid anhydride group-containing carbonate resins, isocyanate group-containing carbonate resins, urethane group-containing carbonate resins, etc. Specific examples of polycarbonate resins include "FPC0220" manufactured by Mitsubishi Gas Chemical Company, Inc., "T6002" and "T6001" (polycarbonate diols) manufactured by Asahi Kasei Corporation, and "C-1090," "C-2090," and "C-3090" (polycarbonate diols) manufactured by Kuraray Co., Ltd.

[0108] A specific example of the polyether ether ketone resin is "Sumiploy K" manufactured by Sumitomo Chemical Co., Ltd.

[0109] Examples of polyester resins include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, and polycyclohexane dimethyl terephthalate resin.

[0110] The amount of (B) polymer resin is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 1.0% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less.

[0111] The amount of (B) polymer resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, relative to 100% by mass of the resin component in the resin composition, and is preferably 10% by mass or less, preferably 8% by mass or less, and more preferably 6% by mass or less.

[0112] The resin composition may contain (C) an inorganic filler as an optional component. The (C) inorganic filler is particles of an inorganic material, and is usually contained in the cured product while maintaining the particle state. The (C) inorganic filler usually increases the melt viscosity of the resin composition. The (C) inorganic filler does not include those corresponding to the above-mentioned components (A) and (B).

[0113] (C) Inorganic filler materials include inorganic compounds. Examples of (C) inorganic filler materials include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium titanate zirconate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica, alumina, and boron nitride are preferred, silica and alumina are more preferred, and silica is even more preferred. Therefore, (C) inorganic filler preferably contains silica, but may contain only silica. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Spherical silica is preferred. (C) The inorganic filler may be used alone or in combination of two or more.

[0114] (C) Examples of commercially available inorganic fillers include "SP60-05" and "SP507-05" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YC100C," "YA050C," "YA050C-MJE," "YA010C," "SC2500SQ," "SO-C4," "SO-C2," and "SO-C1" manufactured by Admatechs Co., Ltd.; "UFP-30," "DAW-01," "DAW-03," "FB-105FD," and "Spherical Nanosize BN" manufactured by Denka Co., Ltd.; "Silfil NSS-3N," "Silfil NSS-4N," and "Silfil NSS-5N" manufactured by Tokuyama Corporation; and "CellSpheres MGH-005" manufactured by Taiheiyo Cement Corporation.

[0115] The average particle size of the (C) inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less.

[0116] (C) The average particle size of an inorganic filler can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, a volumetric particle size distribution of the inorganic filler is created using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is used as the average particle size. A measurement sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing the mixture ultrasonically for 10 minutes. The volumetric particle size distribution of the inorganic filler is measured using a laser diffraction particle size distribution analyzer with blue and red light source wavelengths using a flow cell system, and the average particle size can be calculated as the median diameter from the particle size distribution obtained. Examples of laser diffraction particle size distribution analyzers include the LA-960 manufactured by Horiba, Ltd.

[0117] (C) The specific surface area of ​​inorganic fillers is usually 50m 2 / g or less, preferably 40m 2 / g or less, more preferably 30m 2 The lower limit is preferably 0.1 m / g or less. 2 / g or more, more preferably 0.5m2 / g or more, more preferably 1m 2 / g or more, particularly preferably 3m 2 (C) The specific surface area of ​​particles such as inorganic fillers can be measured in accordance with the BET method by adsorbing nitrogen gas onto the surface of a sample using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) and calculating the specific surface area using the BET multipoint method.

[0118] From the viewpoint of improving moisture resistance and dispersibility, the inorganic filler (C) is preferably treated with a surface treatment agent. Examples of the surface treatment agent include the same examples as the surface treatment agent for the fiber substrate 210. The surface treatment agent for the fiber substrate 210 and the surface treatment agent for the inorganic filler (C) may be the same or different. Furthermore, one type of surface treatment agent may be used alone, or two or more types may be used in combination.

[0119] The degree of surface treatment with the surface treatment agent preferably falls within a specific range from the viewpoint of improving the dispersibility of the inorganic filler. Specifically, 100% by mass of the inorganic filler is preferably surface-treated with 0.2% to 5% by mass of the surface treatment agent, more preferably with 0.2% to 3% by mass of the surface treatment agent, and even more preferably with 0.3% to 2% by mass of the surface treatment agent.

[0120] The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of ​​the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of ​​the inorganic filler is set to 0.02 mg / m 2 More than 0.1 mg / m is preferable. 2 More preferably, 0.2 mg / m or more 2 On the other hand, from the viewpoint of suppressing an excessive increase in the melt viscosity of the resin composition, it is more preferable that the content be 1.0 mg / m 2 Less than 0.8 mg / m is preferred 2 Less than 0.5 mg / m is more preferable. 2 The following is even more preferred:

[0121] (C) The amount of carbon per unit surface area of ​​the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solid content, the amount of carbon per unit surface area of ​​the inorganic filler can be measured using a carbon analyzer. An "EMIA-320V" manufactured by Horiba, Ltd., or the like can be used as the carbon analyzer.

[0122] The amount of (C) inorganic filler is preferably 50% by mass or more, more preferably 53% by mass or more, even more preferably 55% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 80% by mass or less, more preferably 75% by mass or less, even more preferably 70% by mass or less.

[0123] The resin composition may contain an organic filler (D) as an optional component. The organic filler (D) is usually incompatible with resin components other than the organic filler (D), is contained in the resin composition in the form of particles, and is contained in the cured product while maintaining this particulate state. The organic filler (D) usually increases the melt viscosity of the resin composition. The organic filler (D) does not include those corresponding to the above-mentioned components (A) to (C). Furthermore, one type of organic filler (D) may be used alone, or two or more types may be used in combination.

[0124] The (D) organic filler may be particles of an organic material. A rubber component is preferred as the organic material contained in the (D) organic filler. Examples of rubber components include silicone-based elastomers such as polydimethylsiloxane; olefin-based thermoplastic elastomers such as polybutadiene, polyisoprene, polychlorobutadiene, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-isobutylene copolymer, acrylonitrile-butadiene copolymer, isoprene-isobutylene copolymer, isobutylene-butadiene copolymer, ethylene-propylene-diene terpolymer, and ethylene-propylene-butene terpolymer; and thermoplastic elastomers such as acrylic thermoplastic elastomers such as polypropyl(meth)acrylate, polybutyl(meth)acrylate, polycyclohexyl(meth)acrylate, and polyoctyl(meth)acrylate. Furthermore, silicone-based rubbers such as polyorganosiloxane rubbers may be mixed into the rubber component. The rubber component contained in the rubber particles has a glass transition temperature of, for example, 0°C or lower, preferably -10°C or lower, more preferably -20°C or lower, and even more preferably -30°C or lower.

[0125] The (D) organic filler may be a core-shell type rubber particle consisting of a core particle containing the above-mentioned rubber component and a shell portion formed by graft copolymerization of a monomer component copolymerizable with the rubber component contained in the core particle. Here, the term "core-shell type" does not necessarily refer only to those in which the core particle and the shell portion are clearly distinguishable, but also includes those in which the boundary between the core particle and the shell portion is unclear, and the core particle does not necessarily have to be completely covered with the shell portion.

[0126] Specific examples of (D) organic fillers include "CHT" manufactured by Samsung SDI; "B602" manufactured by Techno UMG; "Paraloid EXL-2602", "Paraloid EXL-2603", "Paraloid EXL-2655", "Paraloid EXL-2311", "Paraloid-EXL2313", "Paraloid EXL-2315", "Paraloid KM-330", "Paraloid KM-336P", and "Paraloid KCZ-201" manufactured by Dow; and "Metabrene C-223A" and "Metabrene E- 901," "Metabrene S-2001," "Metabrene W-450A," and "Metabrene SRK-200" manufactured by Kaneka Corporation; "Kane Ace M-511," "Kane Ace M-600," "Kane Ace M-400," "Kane Ace M-580," and "Kane Ace MR-01" manufactured by Kaneka Corporation; and "Staphyloid AC3355," "Staphyloid AC3816," "Staphyloid AC3816N," "Staphyloid AC3832," "Staphyloid AC4030," and "Staphyloid AC3364" manufactured by Aica Kogyo Co., Ltd.

[0127] The amount of (D) organic filler is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 10% by mass or less, more preferably 6% by mass or less, and even more preferably 3% by mass or less.

[0128] The amount of (D) organic filler is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, relative to 100% by mass of the resin component in the resin composition, and is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0129] The resin composition may contain a (E) curing accelerator as an optional component. The (E) curing accelerator acts as a catalyst in the reaction of the (A) thermosetting resin, such as an epoxy resin, and can accelerate the reaction, thereby promoting an increase in the melt viscosity of the resin composition during lamination in step (II). The (E) curing accelerator does not include components (A) to (D). One (E) curing accelerator may be used alone, or two or more may be used in combination.

[0130] Examples of the (E) curing accelerator include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, and amine-based curing accelerators.

[0131] Examples of the phosphorus-based curing accelerator include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitate, tetrabutylphosphonium hydrogenhexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butyldimethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, and tetraphenylphosphonium tetra-p-tolylborate. aromatic phosphonium salts such as tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone adducts such as triphenylphosphine-p-benzoquinone adduct; aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine;Dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine aromatic phosphines such as benzene, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, and 2,2'-bis(diphenylphosphino)diphenyl ether;

[0132] Examples of the urea-based curing accelerator include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. aromatic dimethylureas such as toluene bis(dimethylurea), 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N',N'-dimethylurea), and N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluene bisdimethylurea].

[0133] Examples of guanidine curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

[0134] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-methylimidazole. Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl -(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct Examples of imidazole compounds include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins. Commercially available imidazole curing accelerators include "1B2PZ," "2E4MZ," "2MZA-PW," "2MZ-OK," "2MA-OK," "2MA-OK-PW," "2PHZ," "2PHZ-PW," "Cl1Z," "Cl1Z-CN," "Cl1Z-CNS," and "C11Z-A" manufactured by Shikoku Chemicals Corporation; and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

[0135] Examples of metal-based curing accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organic cobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organic copper complexes such as copper(II) acetylacetonate, organic zinc complexes such as zinc(II) acetylacetonate, organic iron complexes such as iron(III) acetylacetonate, organic nickel complexes such as nickel(II) acetylacetonate, and organic manganese complexes such as manganese(II) acetylacetonate. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0136] Examples of the amine curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5.4.0)-undecene, etc. Commercially available amine curing accelerators may be used, such as "MY-25" manufactured by Ajinomoto Fine-Techno Co., Inc.

[0137] The amount of (E) curing accelerator is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.05% by mass or more, and is preferably 2% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, relative to 100% by mass of non-volatile components in the resin composition.

[0138] The amount of (E) curing accelerator is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, relative to 100% by mass of the resin component in the resin composition, and is preferably 5% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less.

[0139] The resin composition may further contain (F) an optional additive as an optional component. The (F) optional additive does not include components (A) to (E) described above. Examples of the (F) optional additive include organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as bentone and montmorillonite; antifoaming agents such as silicone-based antifoaming agents, acrylic-based antifoaming agents, fluorine-based antifoaming agents, and vinyl resin-based antifoaming agents; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; adhesion improvers such as urea silanes; triazole-based adhesion promoters, tetrazole-based adhesion promoters, and triazine-based adhesion promoters. Examples of the additives include adhesion-imparting agents such as adhesion promoters, antioxidants such as hindered phenol antioxidants, fluorescent brighteners such as stilbene derivatives, surfactants such as fluorine-based surfactants and silicone-based surfactants, flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, and red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide), dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants, and stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic anhydride-based stabilizers. (F) Optional additives may be used singly or in combination of two or more.

[0140] The resin composition may further contain a (G) solvent as an optional volatile component in addition to the non-volatile components (A) to (F) described above. An organic solvent is typically used as the (G) solvent. Examples of the organic solvent include ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether-based solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, and anisole; alcohol-based solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples of suitable solvents include ether ester solvents such as ethyl acetate; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. (G) Solvents may be used singly or in combination of two or more.

[0141] The amount of (G) solvent, relative to 100% by mass of all components in the resin composition, may be, for example, 5% by mass or less, 3% by mass or less, 2% by mass or less, 1.5% by mass or less, 1.0% by mass or less, or may be 0% by mass.

[0142] The resin composition can be produced, for example, by mixing components that can be contained in the resin composition. The components may be mixed partially or entirely at the same time, or may be mixed sequentially. The temperature may be appropriately set during the process of mixing each component, and thus heating and / or cooling may be performed temporarily or throughout. Furthermore, stirring or shaking may be performed during the process of mixing each component.

[0143] The thickness of the prepreg 200 is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, and even more preferably 50 μm or less. Conventionally, when using such a thin prepreg, filament exposure has been prone to occur, but this embodiment can prevent filament exposure. The lower limit of the thickness of the prepreg 200 can be, for example, 5 μm or more, 10 μm or more, or 20 μm or more. The above thickness range of the prepreg 200 represents the range in step (I). However, since lamination and flattening generally do not result in a significant change in thickness, the prepreg 200 in steps (II) and thereafter can also have a thickness within the above range.

[0144] The prepreg 200 can be cured by curing the resin composition 220 contained in the prepreg 200. Typically, heat is applied when curing the prepreg 200, and volatile components such as (G) solvent among the components contained in the prepreg 200 may volatilize due to the heat during curing. Therefore, the cured product obtained by curing the prepreg 200 may contain the non-volatile components of the resin composition 220, such as the components (A) to (F), or reaction products thereof, as well as the fiber base material.

[0145] The cured product of the prepreg 200 preferably has excellent dielectric properties, specifically, a low dielectric dissipation factor Df. In one example, the dielectric dissipation factor Df of the cured product of the prepreg 200 is preferably 0.0070 or less, more preferably 0.0060 or less, and even more preferably 0.0050 or less. There is no particular lower limit to the dielectric dissipation factor Df, and it can be, for example, 0.0010 or more. The dielectric dissipation factor Df of the cured product of the prepreg 200 can be measured by a cavity resonance perturbation method under measurement conditions of a measurement frequency of 5.8 GHz and a measurement temperature of 23°C.

[0146] The resin sheet piece 10 may include any optional member as necessary. For example, the resin sheet piece 10 may include a protective film (not shown) that protects the prepreg 200. The protective film is usually provided on the surface of the prepreg 200 that is not bonded to the support 100 (i.e., the surface opposite the support 100). As the protective film, for example, the same film as that of the support 100 may be used. The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. When the protective film is provided, adhesion of dust and scratches to the surface of the prepreg 200 can be suppressed. Usually, the resin sheet piece 10 is subjected to the laminate manufacturing method after the protective film is peeled off.

[0147] There are no particular limitations on the method for manufacturing the resin sheet pieces 10. For example, the resin sheet pieces 10 may be manufactured by a method including manufacturing the prepreg 200 by a manufacturing method such as a hot melt method or a solvent method. In particular, from the viewpoint of manufacturing the resin sheet pieces 10 with high productivity, the resin sheet pieces 10 are A step of preparing a long resin sheet including a support and a prepreg; A step of cutting the long resin sheet to obtain resin sheet pieces; It is preferable to produce the film by a production method including the steps of:

[0148] A long resin sheet is a long sheet including a long support and a long prepreg formed on the long support. Unless otherwise specified, the term "long" refers to a member having a length that is typically 5 times or more, more preferably 10 times or more, and even more preferably 20 times or more, the width of the member. There is no particular upper limit to the length, and it can be, for example, 100,000 times or less. A long resin sheet may be prepared by purchasing it from the market or by manufacturing it.

[0149] Examples of methods for producing a long resin sheet include the following methods (1) to (4). (1) A resin composition is coated on a support without dissolving the resin composition in a solvent to form a resin composition layer, and the resin composition layer is laminated with a fiber substrate to form a prepreg on the support. (2) A resin composition is applied to a fiber substrate using a coating device such as a die coater to form a prepreg, and then the prepreg and a support are laminated together. (3) A resin varnish is prepared by dissolving a resin composition in a solvent. A fiber substrate is immersed in the resin varnish to impregnate the fiber substrate with the resin varnish. The resin varnish is then dried to form a prepreg. The prepreg is then laminated onto a support. (4) A resin composition layer is formed on the support by applying a resin varnish using a coating device such as a die coater, and this resin composition layer and a fiber substrate are laminated to form a prepreg on the support.

[0150] The method for producing a long resin sheet may include laminating a protective film on the prepreg, if necessary. When a resin varnish is used, the method for producing a long resin sheet may include drying the solvent. The drying conditions are not particularly limited as long as a prepreg having the minimum melt viscosities X and Y that satisfy the above-mentioned requirements is obtained. Specific drying conditions may vary depending on the composition of the resin composition. In one example, the drying temperature is preferably 80°C or higher, more preferably 90°C or higher, and preferably 180°C or lower, more preferably 140°C or lower. The drying time is preferably 3 minutes or longer, preferably 13 minutes or shorter, more preferably 10 minutes or shorter.

[0151] FIG. 4 is a perspective view schematically illustrating a method for manufacturing a resin sheet piece 10 used in a laminate manufacturing method according to one embodiment of the present invention. FIG. 4 illustrates an example in which a long resin sheet 20 is cut while being conveyed in the MD direction. As shown in FIG. 4, the long resin sheet 20 may be prepared and then cut using a cutting device 30 such as an autocutter to manufacture the resin sheet pieces 10. The long resin sheet 20 is generally cut so as to divide the long resin sheet 20 into multiple pieces in the longitudinal direction. Thus, the cutting process can form cut surfaces as the end faces 111 and 12 in the MD direction of the resin sheet piece 10. Hereinafter, the end faces 11 and 12 in the MD direction of the resin sheet piece 10 may be referred to as "MD end faces." The MD end faces 11 and 12 are often formed parallel to the TD direction. Typically, the MD end faces 11 and 12 of the resin sheet piece 10 include the end face of the support 100 (not shown) and the end face of the prepreg 200 (not shown), and these end faces are flush with each other. Two or more surfaces are "flush" if they form a single plane.

[0152] Generally, a long resin sheet 20 includes prepreg 200 over the entire length of the long resin sheet 20. Therefore, a resin sheet piece 10 obtained by cutting the long resin sheet 20 usually includes prepreg 200 over the entire length of the resin sheet piece 10 in the MD direction. Therefore, the length of the support 100 of the resin sheet piece 10 in the MD direction is usually the same as the length of the prepreg 200 of the resin sheet piece 10. Furthermore, when viewed from the thickness direction, the end of the support 100 in the MD direction and the end of the prepreg 200 in the MD direction can overlap, so that the positions of both in the MD direction can match.

[0153] As described above, the method of cutting the long resin sheet 20 allows the resin sheet pieces 10 to be produced with high productivity. Therefore, the method of producing a laminate preferably includes, prior to step (I), step (VI) of cutting the long resin sheet 20 to obtain the resin sheet pieces 10. The produced resin sheet pieces 10 are generally conveyed in the MD direction and supplied to a laminator (see FIG. 5), where step (I) is carried out.

[0154] <Explanation of laminator> Fig. 5 is a cross-sectional view schematically showing a laminator 1 used in a laminate manufacturing method according to one embodiment of the present invention. As shown in Fig. 5, the laminator 1 includes a first stage 300 capable of laminating an inner layer substrate 40 and a prepreg 200 of a resin sheet piece 10, a second stage 400 capable of flattening the prepreg 200, and transport films 510 and 520 capable of transporting the resin sheet piece 10 and the inner layer substrate 40 from the first stage 300 to the second stage 400 in that order.

[0155] The first stage 300 includes a lower press member 310 as a first press member, an upper press member 320 as a second press member disposed opposite the lower press member 310, and a hydraulic cylinder 330 as a drive device. The lower press member 310 and the upper press member 320 have planar pressing surfaces 310U and 320D facing each other, with conveying films 510 and 520 passing between these pressing surfaces 310U and 320D. When driven by the hydraulic cylinder 330, the lower press member 310 contacts one of the conveying films 510 at the pressing surface 310U, and the upper press member 320 contacts the other of the conveying films 520 at the pressing surface 320D. Therefore, the lower press member 310 and the upper press member 320 can press the resin sheet piece 10 and the inner layer substrate 40 between the pressing surfaces 310U and 320D via the conveying films 510 and 520 by a pressing force corresponding to the driving force applied by the drive device 330. In the example shown here, the hydraulic cylinder 330 has a piston rod 331 that is extendable and retractable, and is configured so that the piston rod 331 can be extended and retracted by hydraulic pressure.

[0156] The lower press member 310 includes a lower support member 311 , a lower plate 312 , and a lower frame member 313 .

[0157] The lower support member 311 is provided so as to be able to move forward and backward relative to the upper press member 320. The lower support member 311 has a support surface 311U facing the upper press member 320. The lower support member 311 is also connected to a hydraulic cylinder 330 so that the lower plate 312 can press the resin sheet piece 10 and inner layer substrate 40 supplied between the lower press member 310 and the upper press member 320 via a conveying film 510. Here, an example will be described in which, when the piston rod 331 of the hydraulic cylinder 330 extends, the lower support member 311 rises to approach the upper press member 320, and when the piston rod 331 contracts, the lower support member 311 descends to move away from the upper press member 320.

[0158] The lower plate 312 is a plate member provided on the support surface 311U of the lower support member 311 and has an upper surface 312U as a flat surface facing the upper press member 320. A heater 314 is provided within the lower plate 312 to heat the lower plate 312. The lower plate 312 may be provided so as to contact the support surface 311U of the lower support member 311, or may be provided via any other member. Here, an example will be described in which the lower plate 312 is provided on the support surface 311U via a heat insulating material and a buffer material (not shown). An elastic member 315, typically a rubber sheet, is provided on the upper surface 312U of the lower plate 312 so that the resin sheet piece 10 and the inner layer substrate 40 can be pressed by the elastic member 315. In this case, the surface of the elastic member 315 functions as a pressing surface 310U that abuts against the conveying film 510 and presses the resin sheet piece 10 and the inner layer substrate 40. The pressing surface 310U is typically a flat surface.

[0159] The lower frame member 313 is airtightly mounted on the support surface 311U of the lower support member 311 so as to surround the lower plate 312. The lower frame member 313 is configured so that, when joined to an upper frame member 323 provided on the upper press member 320, it can form a vacuum frame together with the upper frame member 323. Here, an example will be described in which the lower frame member 313 includes a fixed frame portion 316 airtightly fixed to the support surface 311U, a movable frame portion 317 provided slidably relative to the fixed frame portion 316, and an elastic support portion 318 such as a spring that supports the movable frame portion 317 so as to push it up toward the upper press member 320. The space between the fixed frame portion 316 and the movable frame portion 317 is sealed with a sealing material (not shown), so the movable frame portion 317 is slidable while maintaining an airtight state.

[0160] The upper press member 320 includes an upper support member 321 , an upper plate 322 , and an upper frame member 323 .

[0161] The upper support member 321 is provided so as to be movable back and forth relative to the lower press member 310. The upper support member 321 has a support surface 321D facing the lower press member 310. Here, an example will be described in which the lower press member 310 is provided so as to be movable by driving the hydraulic cylinder 330 as described above, and the upper press member 320 is provided so as to be fixed in position. In this example, the movement of the lower press member 310 causes the upper press member 320 to move relative to the lower press member 310, and the resin sheet piece 10 and the inner layer substrate 40 supplied between the lower press member 310 and the upper press member 320 can be pressed via the conveying film 520.

[0162] The upper plate 322 is a plate member provided on the support surface 321D of the upper support member 321 and has a lower surface 322D as a flat surface facing the lower press member 310. A heater 324 is provided within the upper plate 322 to heat the upper plate 322. The upper plate 322 may be provided in contact with the support surface 321D of the upper support member 321, or may be provided via any other member. Here, an example will be described in which the upper plate 322 is provided on the support surface 321D via a heat insulating material and a buffer material (not shown). An elastic member 325, typically a rubber sheet, is provided on the lower surface 322D of the upper plate 322 so that the resin sheet piece 10 and the inner layer substrate 40 can be pressed by the elastic member 325. In this case, the surface of the elastic member 325 functions as a pressing surface 320D that abuts against the conveying film 520 and presses the resin sheet piece 10 and the inner layer substrate 40. The pressing surface 320D is typically a flat surface.

[0163] The upper frame member 323 is airtightly attached to the support surface 321D of the upper support member 321 so as to surround the upper plate 322. This upper frame member 323 is arranged so that when joined to the lower frame member 313 provided in the lower press member 310, it can form a vacuum frame together with the lower frame member 313. In addition, the upper frame member 323 is provided with a nozzle 326, to which a pressure adjustment device (not shown) such as a vacuum pump is connected.

[0164] The second stage 400 is disposed downstream of the first stage 300, similar to the first stage 300. The second stage 400 includes a lower press member 410 as a third press member, an upper press member 420 as a fourth press member disposed opposite the lower press member 410, and a hydraulic cylinder 430 as a drive device. The lower press member 410 and the upper press member 420 have planar pressing surfaces 410U and 420D facing each other, with conveying films 510 and 520 passing between the pressing surfaces 410U and 420D. When driven by the hydraulic cylinder 430, the lower press member 410 contacts one of the conveying films 510 at the pressing surface 410U, and the upper press member 420 contacts the other of the conveying films 520 at the pressing surface 420D. Therefore, the lower press member 410 and the upper press member 420 can press the resin sheet piece 10 and the inner layer substrate 40 between the pressing surface 410U and the pressing surface 420D via the conveying films 510 and 520 by a pressing force corresponding to the driving force applied by the drive device 430. The hydraulic cylinder 430 is provided in the same manner as the hydraulic cylinder 330 of the first stage 300, and has a piston rod 431 similar to the piston rod 431.

[0165] The lower pressing member 410 includes a lower support member 411, a lower plate 412, and a lower frame member 413. An elastic member 415 is typically provided on the upper surface 412U of the lower plate 412, and the surface of the elastic member 415 functions as a pressing surface 410U that contacts the conveying film 510 and presses the resin sheet piece 10 and the inner layer substrate 40. The pressing surface 410U is typically a flat surface. The lower support member 411, lower plate 412, and lower frame member 413 are provided in the same manner as the lower support member 311, lower plate 312, and lower frame member 313 of the first stage 300. Thus, the lower support member 411 is provided so as to be movable back and forth relative to the upper pressing member 420, and has a support surface 411U facing the upper pressing member 420. The lower plate 412 also has an upper surface 412U facing the upper pressing member 420, and is further provided with a heater 414 to adjust the pressing temperature. In addition, the lower frame material 413 is provided with a fixed frame portion 416, a movable frame portion 417 and an elastic support portion 418 that are provided in the same manner as the fixed frame portion 316, the movable frame portion 317 and the elastic support portion 318, so that when joined with the upper frame material 423 that the upper press material 420 has, a vacuum frame can be formed together with the upper frame material 423.

[0166] The upper pressing member 420 includes an upper support member 421, an upper plate 422, and an upper frame member 423. An elastic member 425 is typically provided on the lower surface 422D of the upper plate 422, and the surface of the elastic member 425 functions as a pressing surface 420D that contacts the conveying film 520 and presses the resin sheet piece 10 and the inner layer substrate 40. The pressing surface 420D is typically a flat surface. The upper support member 421, upper plate 422, and upper frame member 423 are provided in the same manner as the upper support member 321, upper plate 322, and upper portion 323 of the first stage 300. Thus, the upper support member 421 is provided so as to be movable back and forth relative to the lower pressing member 410, and has a support surface 421D facing the lower pressing member 410. The upper plate 422 also has a lower surface 422D facing the lower pressing member 410, and is further provided with a heater 424 to adjust the pressing temperature. Furthermore, the upper frame member 423 may be provided with a nozzle 426, and this nozzle 426 may be connected to a pressure adjusting device (not shown) such as a vacuum pump.

[0167] The carrier films 510 and 520 are both long films formed so as to be able to run while supporting the resin sheet pieces 10 and the inner layer substrate 40, and for example, long resin films may be used. The carrier films 510 and 520 are arranged to pass through the first stage 300 and the second stage 400. Specifically, the carrier films 510 and 520 are arranged to pass between the lower press member 310 and the upper press member 320 of the first stage 300. The carrier films 510 and 520 are also arranged to pass between the lower press member 410 and the upper press member 420 of the second stage 400.

[0168] Typically, the conveying films 510 and 520 are arranged to be able to run while holding the resin sheet pieces 10 and the inner layer substrate 40, or the laminate 50, between one conveying film 510 and the other conveying film 520. Therefore, the running of the conveying films 510 and 520 performs the supply of the resin sheet pieces 10 and the inner layer substrate 40 to the first stage 300, the transport of the resin sheet pieces 10 and the inner layer substrate 40 from the first stage 300 to the second stage 400, and the removal of the laminate 50 from the second stage 400.

[0169] <Explanation of Step (I)> The method for manufacturing a laminate according to this embodiment includes step (I), as shown in FIG. 5, of supplying a resin sheet piece 10 and an inner layer substrate 40 to a first stage 300 to obtain a state in which a conveying film 520, a support 100, a prepreg 200 and an inner layer substrate 40 are stacked in this order.

[0170] The "inner layer substrate" 40 refers to a component that serves as the base material of a circuit board, and examples thereof include a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate. The inner layer substrate 40 may also have a conductor layer (not shown) on one or both sides. For example, the inner layer substrate 40 may include a support substrate and a conductor layer formed on the support substrate. The conductor layer of the inner layer substrate 40 may be patterned. An inner layer substrate 40 having a conductor layer (circuit) formed on one or both sides of the substrate may be referred to as an "inner layer circuit board." In addition, the term "inner layer substrate" also includes intermediate products on which insulating layers and / or conductor layers are to be formed during the manufacture of a circuit board. An inner layer substrate 40 equipped with components may also be used.

[0171] The conductor layer provided on the inner substrate 40 is the outermost layer of the inner substrate 40 and is exposed on the surface of the inner substrate 40. The conductor layer may be exposed on the surface of the inner substrate 40 facing the resin sheet piece 10. In this case, the prepreg 200 laminated to the inner substrate 40 can be in direct contact with this conductor layer. Two members being in "direct" contact means that there is no other member between the two members in contact.

[0172] In the past, when the surface roughness of the conductor layer in contact with the prepreg was small, fiber exposure from the edge of the prepreg tended to occur in the resulting laminate. However, according to the manufacturing method of this embodiment, this fiber exposure can be suppressed even if the surface roughness of the conductor layer is small. Therefore, from the perspective of utilizing the effect of suppressing fiber exposure, it is preferable that the surface roughness of the conductor layer of the inner layer substrate 40 in contact with the prepreg 200 is small. Specifically, the arithmetic mean roughness Ra of the conductor layer is preferably 250 nm or less, more preferably 200 nm or less, and even more preferably 150 nm or less. There is no particular lower limit and it can be, for example, 10 nm or more, 50 nm or more, etc.

[0173] In step (I), the inner layer substrate 40 and the resin sheet 10 are typically placed between the carrier films 510 and 520, and the inner layer substrate 40 and the resin sheet 10 are held between the carrier films 510 and 520. The carrier films 510 and 520 are then run. As a result, as shown in FIG. 5 , the carrier film 520, the support 100, the prepreg 200, the inner layer substrate 40, and the carrier film 510 are supplied in this order between the lower press member 310 and the upper press member 320 of the first stage 300.

[0174] <Explanation of Step (II)> The method for producing the laminate 50 according to this embodiment includes, after step (I), step (II) of pressing the resin sheet pieces 10 and the inner layer substrate 40 while applying heat in a reduced pressure environment in a first stage 300. This pressing is performed by applying pressure in the thickness direction, and the prepreg 200 of the resin sheet pieces 10 and the inner layer substrate 40 are laminated together.

[0175] FIG. 6 is a cross-sectional view schematically illustrating the state in which the resin sheet piece 10 and the inner layer substrate 40 are pressed in step (II) of the laminate manufacturing method according to one embodiment of the present invention. Specifically, in step (II), as shown in FIG. 6, the hydraulic cylinder 330 is driven to extend the piston rod 331. As the piston rod 331 extends, the lower press member 310 rises and approaches the upper press member 320. As the lower press member 310 rises, the upper frame member 323 presses the movable frame portion 317 of the lower frame member 313 via the conveying films 510 and 520. This closes the gap between the lower frame member 313 and the upper frame member 323, forming a closed space surrounded by the lower support member 311, the upper support member 321, the lower frame member 313, and the upper frame member 323. A pressure regulator (not shown) then depressurizes the closed space through a nozzle 326. This depressurization creates a reduced-pressure environment within the closed space, with a specific range of vacuum level.

[0176] Furthermore, as the lower press member 310 rises, the pressing surface 310U of the heated lower press member 310 eventually comes into contact with the carrier film 510 and presses the resin sheet piece 10 and the inner layer substrate 40 via the carrier film 510. Furthermore, the pressing surface 320D of the heated upper press member 320 comes into contact with the carrier film 520 and presses the resin sheet piece 10 and the inner layer substrate 40 via the carrier film 520. Therefore, the resin sheet piece 10 and the inner layer substrate 40 are pressed while being heated between the carrier film 510 and the carrier film 520, and lamination of the prepreg 200 of the resin sheet piece 10 and the inner layer substrate 40 progresses.

[0177] Specifically, the process is as follows: After a vacuum environment is formed in the closed space containing the carrier film 510, the inner layer substrate 40, the resin sheet piece 10, and the carrier film 520, the hydraulic cylinder 330 further raises the lower press member 310. The rise of the lower press member 310 presses the resin sheet piece 10 and the inner layer substrate 40. During pressing, the lower plate 312 and the upper plate 322, heated by the heaters 314 and 324, are heated to a specific pressing temperature range. The driving force of the hydraulic cylinder 330 is set so that the pressing surfaces 310U and 320D press the resin sheet piece 10 and the inner layer substrate 40 with a specific pressing pressure range. Therefore, pressing is performed on the resin sheet piece 10 and the inner layer substrate 40 at a specific pressing temperature, with a specific pressing pressure, and for a specific pressing time, thereby achieving lamination of the prepreg 200 and the inner layer substrate 40.

[0178] The pressing temperature, pressing pressure, and pressing time in step (II) are set so that the minimum melt viscosity Y and the viscosity ratio Y / X satisfy the above-mentioned requirements. The specific ranges of the pressing temperature, pressing pressure, and pressing time can be set depending on the composition of the prepreg 200. In one example, the preferred ranges are as follows:

[0179] The pressing temperature range in step (II) is preferably 80°C or higher, more preferably 100°C or higher, even more preferably 125°C or higher, and preferably 170°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower. The pressing pressure range in step (II) is preferably 0.01 MPa or higher, more preferably 0.1 MPa or higher, even more preferably 0.3 MPa or higher, and preferably 1.5 MPa or lower, more preferably 1.2 MPa or lower, and even more preferably 0.9 MPa or lower. The pressing time range in step (II) is preferably 30 seconds or higher, more preferably 60 seconds or higher, even more preferably 120 seconds or higher, and preferably 1800 seconds or lower, more preferably 1500 seconds or lower, and even more preferably 1200 seconds or lower.

[0180] The pressing of the resin sheet piece 10 and the inner layer substrate 40 in step (II) is carried out in a reduced pressure environment with a specific range of vacuum. The range of vacuum is usually 10 kPa or less, preferably 5 kPa or less, and more preferably 1 kPa or less. The lower limit is ideally 0 kPa or more, but is usually above 0.01 kPa. By performing lamination at such a high level of vacuum, it is possible to suppress the formation of voids.

[0181] In step (II), the resin composition in the prepreg 200 becomes flexible due to heat. The flexible resin composition flows due to the pressure applied by pressing, and adheres to the surface of the inner substrate 10. For example, if the inner substrate 10 has a conductor layer (not shown), the fluidized resin composition embeds the conductor layer. Thus, the prepreg 200 is bonded to the surface of the inner substrate 10. After the prepreg 200 is bonded to the surface of the inner substrate 10, the vacuum state in the closed space is released through the nozzle 326, and the piston rod 331 is retracted to lower the lower press member 310.

[0182] <Explanation of Step (III)> The manufacturing method of the laminate 50 according to this embodiment includes, after step (II), step (III) of transporting the resin sheet pieces 10 and the inner layer substrate 40 to the second stage 400 by the transport films 510 and 520. In step (III), the transport films 510 and 520 are typically run to transport the resin sheet pieces 10 and the inner layer substrate 40 between the lower press member 410 and the upper press member 420 of the second stage 400, as shown in Fig. 5. Between the lower press member 410 and the upper press member 420, the transport film 520, the support 100, the prepreg 200, the inner layer substrate 40, and the transport film 510 are transported in this order while overlapping each other.

[0183] <Explanation of Step (IV)> The method for producing the laminate 50 according to this embodiment includes, after step (III), step (IV) of pressing the resin sheet pieces 10 and the inner layer substrate 40 while applying heat in the second stage 400. This pressing applies pressure in the thickness direction to flatten the prepreg 200, thereby increasing the uniformity of the surface height of the prepreg 200. Specifically, step (IV) can reduce undulations in the prepreg 200.

[0184] 7 is a cross-sectional view schematically illustrating the state in which the resin sheet piece 10 and the inner layer substrate 40 are pressed in step (IV) of the laminate manufacturing method according to one embodiment of the present invention. Specifically, in step (IV), as shown in FIG. 7, the hydraulic cylinder 430 is driven to extend the piston rod 431, thereby raising the lower press member 410 and bringing it closer to the upper press member 420. When the lower press member 410 rises, the gap between the lower frame member 413 and the upper frame member 423 closes, similar to the gap between the lower frame member 313 and the upper frame member 323 in the first stage. This forms a closed space surrounded by the lower support member 411, the upper support member 421, the lower frame member 413, and the upper frame member 423. If necessary, a pressure regulator (not shown) may reduce the pressure in the closed space through a nozzle 426 to create a reduced-pressure environment within the closed space.

[0185] As the lower press member 410 rises, the pressing surface 410U of the heated lower press member 410 eventually comes into contact with the carrier film 510 and presses the resin sheet pieces 10 and the inner layer substrate 40 via the carrier film 510. In addition, the pressing surface 420D of the heated upper press member 420 comes into contact with the carrier film 520 and presses the resin sheet pieces 10 and the inner layer substrate 40 via the carrier film 520. Therefore, the resin sheet pieces 10 and the inner layer substrate 40 are pressed while being heated between the carrier film 510 and the carrier film 520, and the prepreg 200 can be flattened.

[0186] Specifically, the process is as follows. After forming a closed space containing the carrier film 510, the inner layer substrate 40, the resin sheet piece 10, and the carrier film 520, the hydraulic cylinder 430 further raises the lower press member 410. As the lower press member 410 rises, it presses the resin sheet piece 10 and the inner layer substrate 40. During pressing, the lower plate 412 and the upper plate 422, heated by the heaters 414 and 424, are heated to a specific pressing temperature range. The driving force of the hydraulic cylinder 430 is set so that the pressing surfaces 410U and 420D press the resin sheet piece 10 and the inner layer substrate 40 with a specific pressing pressure range. Therefore, pressing is performed on the resin sheet piece 10 and the inner layer substrate 40 at a specific pressing temperature, a specific pressing pressure, and for a specific pressing time, flattening the prepreg 200 and improving the uniformity of the surface height of the prepreg 200.

[0187] The pressing temperature, pressing pressure, and pressing time in step (IV) are preferably set so as to sufficiently enhance the uniformity of the surface height of the prepreg 200. The pressing temperature in step (IV) is preferably 60°C or higher, more preferably 80°C or higher, even more preferably 105°C or higher, and preferably 160°C or lower, more preferably 150°C or lower, and even more preferably 140°C or lower. The pressing pressure in step (IV) is preferably 0.01 MPa or higher, more preferably 0.1 MPa or higher, even more preferably 0.3 MPa or higher, and preferably 1.5 MPa or lower, more preferably 1.0 MPa or lower, and even more preferably 0.6 MPa or lower. The pressing time in step (IV) is preferably 20 seconds or higher, more preferably 30 seconds or higher, even more preferably 60 seconds or higher, and preferably 180 seconds or lower, more preferably 150 seconds or lower, and even more preferably 120 seconds or lower.

[0188] In step (IV), the resin composition in the prepreg 200 becomes flexible due to heat. The flexible resin composition flows due to the pressure applied by pressing, so the surface of the prepreg 200 (the surface opposite the inner layer substrate 40) becomes flat. This results in a laminate 50 comprising the inner layer substrate 40 and the resin sheet piece 10 comprising the flattened prepreg 200. After the surface of the prepreg 200 has been flattened, the piston rod 431 is retracted to lower the lower press member 410.

[0189] <Explanation of Process (V)> The method for producing the laminate 50 according to this embodiment includes, after step (IV), step (V) of removing the laminate 50 from the carrier films 510 and 520. In step (V), the carrier films 510 and 520 are usually run to remove the laminate 50 from the laminator 1. Then, the laminate 50 removed from the laminator 1 is removed from the carrier films 510 and 520.

[0190] Fig. 8 is a cross-sectional view schematically showing a laminate 50 produced by a production method according to one embodiment of the present invention. As shown in Fig. 8, the production method according to an embodiment of the present invention produces a laminate 50 having an inner layer substrate 40, a prepreg 200, and a support 100 in this order in the thickness direction.

[0191] In the manufactured laminate 50, it is possible to prevent the filaments of the fiber substrate (not shown in FIG. 8) from protruding and becoming exposed from the MD end faces 11 and 12 of the resin sheet piece 10. Therefore, it is possible to reduce the amount of filaments that are not encapsulated in the resin composition and are exposed from the MD end faces 11 and / or 12, and preferably, all of the filaments can be encapsulated in the resin composition.

[0192] In the laminate 50 produced, the flatness of the surface 200U of the prepreg 200 laminated to the inner layer substrate 40 can be improved. Specifically, the uniformity of the height of the surface 200U of the prepreg 200 can be improved. The flatness of the surface 200U of the prepreg 200 can be evaluated by the undulation of the prepreg 200. This undulation represents the difference between the maximum height and the minimum height of the surface 200U of the prepreg 200 opposite the inner layer substrate 40. According to the production method of this embodiment, the undulation can be reduced to preferably less than 2.0 μm, more preferably less than 1.8 μm, and even more preferably less than 1.6 μm. The undulation of the prepreg 200 can be measured, for example, by the method described in the "Method for Evaluating the Flatness of a Prepreg After Lamination" section of the Examples described below.

[0193] The laminate 50 thus produced can generally suppress the formation of voids in the prepreg 200. Voids can be confirmed by observation under a microscope.

[0194] The mechanism by which the above-mentioned excellent effects are obtained will be explained below in comparison with the prior art, however, the technical scope of the present invention is not limited by the mechanism explained below.

[0195] 9 is a cross-sectional view schematically illustrating a process in which a conventional resin sheet piece 80 including a support 800 and a prepreg 900 is laminated with an inner layer substrate 40, and then pressed in a second stage to flatten the prepreg 900. For example, as shown in FIG. 9, the laminated resin sheet piece 80 and inner layer substrate 40 are transported to the second stage by carrier films 510 and 520, and pressed between a pressing surface 410U of a lower press member 410 and a pressing surface 420D of an upper press member 420 while applying heat, thereby flattening the prepreg 900. The resin composition 920 in the prepreg 900 becomes flexible due to the heat and flows due to the pressure caused by the pressing.

[0196] Unlike vacuum pressing, pressing using a laminator leaves the in-plane end faces of the prepreg 900 open. That is, in vacuum pressing, the prepreg is typically placed so as to fill the entire cavity of a mold that forms a closed space. Since the in-plane end faces of the prepreg are restricted by the inner walls of the mold, the resin composition in the prepreg does not significantly leak out in the in-plane direction. In contrast, lamination using a laminator involves pressing between the opposing pressing surfaces 410U and 420D, leaving the in-plane end faces of the prepreg 900 open. Therefore, during pressing, the resin composition 920 in the fluidized prepreg 900 may leak out from the portion between the inner layer substrate 40 and the support 800, forming an overhang 950. Generally, laminates of prepreg 900 containing a fiber substrate 40 tend to have poorer embeddability of the conductor layer on the surface of the inner layer substrate 40 compared to laminates of resin sheets having a resin composition layer that does not contain a fiber substrate 40. Therefore, since the composition of the resin composition 920 is generally adjusted to have high fluidity, a large amount of the resin composition 920 is likely to flow out and form the protruding portion 950. In this case, if the density of the filaments 931 of the fiber base material 910 in the prepreg 900 is low, the fiber base material 910 has low bundling ability and low retention force to prevent the movement of the filaments 931. Therefore, some of the filaments 931 (usually the filaments of the warp threads 930) may flow into the protruding portion 950 as the resin composition 920 flows.

[0197] FIG. 10 is a cross-sectional view schematically illustrating a laminate 90 obtained by laminating a conventional resin sheet piece 80 with an inner layer substrate 40 and flattening the laminate. As shown in FIG. 10, when the laminate 90 having an overhang 950 (see FIG. 9 ) formed thereon is removed from the carrier films 510 and 520 (see FIG. 9 ), the resin composition 920 in the overhang 950 adheres to the carrier film 520 and is sometimes removed. When the resin composition 920 in the overhang 950 is removed, the filament 931 contained within the overhang 950 overhangs the end surface 900S of the prepreg 900. Therefore, the filament 931 is exposed from the end surface 900S of the prepreg 900 in the resulting laminate 90. In particular, when the surface roughness of the conductor layer (not shown) on the surface of the inner layer substrate 40 is small, the anchor effect tends to weaken the ability to retain the resin composition 920 in the overhang 950, making the filament 931 particularly susceptible to exposure.

[0198] The inventors' investigations have revealed that the formation of the protrusion portion 950 is more likely to occur during planarization than during lamination. Therefore, in the manufacturing method according to the above-described embodiment, the viscosity ratio Y / X is set within a specific range. This viscosity ratio Y / X indicates that the heat applied during lamination in step (II) promotes the reaction of the thermosetting resin, significantly increasing the minimum melt viscosity of the prepreg 200. Therefore, the prepreg 200 can have a small minimum melt viscosity X during lamination in step (II). This increases the fluidity of the resin composition 220, thereby enabling the resin composition 220 to effectively embed the conductor layer on the surface of the inner substrate 40. Furthermore, the prepreg 200 can have a large minimum melt viscosity Y when supplied for planarization in step (IV). This reduces the fluidity of the resin composition 220, thereby preventing the resin composition 220 from flowing out from the portion between the inner layer substrate 40 and the support 100, thereby preventing the formation of protruding portions, as shown in Fig. 7. This prevents the filaments 231 from being exposed at the end 200E in the MD of the prepreg 200, as shown in Fig. 8.

[0199] Furthermore, in the manufacturing method according to the embodiment described above, the minimum melt viscosity Y of the prepreg 200 supplied for planarization in step (IV) is set to be sufficiently low. Therefore, the resin composition 220 in the prepreg 200 pressed for planarization can have sufficiently high fluidity from the viewpoint of planarization. Therefore, as shown in FIG. 8, the planarization of the prepreg 200 can be improved.

[0200] <Optional step description> The method for producing a laminate according to this embodiment may further include any optional steps in combination with the steps described above. For example, the method for producing a laminate may include a step of peeling off the support after step (V). When the support is peeled off, a laminate comprising an inner layer substrate and a prepreg can be obtained.

[0201] <Example of change> The present invention is not limited to the above-described embodiment, and may be further modified. For example, although the above-described embodiment shows an example in which a prepreg is laminated on one side of the inner layer substrate, the prepreg may be laminated on both sides of the inner layer substrate.

[0202] Fig. 11 is a schematic cross-sectional view illustrating a method for producing a laminate according to another embodiment of the present invention. As shown in Fig. 11, resin sheet pieces 10a and 10b may be laminated on both sides of an inner layer substrate 40 using the laminator 1 described in the above embodiment to produce a laminate including a prepreg 200a, an inner layer substrate 40, and a prepreg 200b in this order.

[0203] This manufacturing method may be carried out in the same manner as the above-described embodiment, except that the resin sheet 10a, the inner layer substrate 40, and the resin sheet 10b are stacked in this order between the carrier film 510 and the carrier film 520. Therefore, in the example shown in FIG. 11, the manufacturing method of the laminate is as follows: a step (I) of supplying resin sheet pieces 10a and 10b and an inner layer substrate 40 to a first stage 300 to obtain a state in which a carrier film 510, a support 100a, a prepreg 200a, an inner layer substrate 40, a prepreg 200b, a support 100b and a carrier film 520 are stacked in this order; In the first stage 300, a step (II) of pressing the resin sheet pieces 10a and 10b and the inner layer substrate 40 while applying heat in a reduced pressure environment; a step (III) of transporting the resin sheet pieces 10a and 10b and the inner layer substrate 40 to a second stage 400 by transport films 510 and 520; In a second stage 400, the resin sheet pieces 10a and 10b and the inner layer substrate 400 are pressed while being heated to obtain a laminate 50 (step (IV)); a step (V) of removing the laminate 50 from the carrier films 510 and 520; In addition, after the step (V), the supports 100a and 100b may be peeled off.

[0204] This manufacturing method can produce a laminate having prepreg 200a, inner layer substrate 40, and prepreg 200b in this order. The two resin sheet pieces 10a and 10b may be the same or different. Therefore, the two prepregs 200a and 200b may be the same or different. As shown in FIG. 11, the manufacturing method in which prepregs 200a and 200b are laminated on both sides of the inner layer substrate 40 can also produce the same effects as the manufacturing method in which prepreg 200 is laminated on one side of the inner layer substrate 40 described above.

[0205] In the above embodiment, the nozzles 326 and 426 are provided on the upper frame members 323 and 423 of the laminator 1, but the position of the nozzles may be changed. For example, the nozzles may be provided on the lower frame members 313 and 413, the lower support members 311 and 411, the upper support members 321 and 421, or two or more of these.

[0206] Furthermore, in the above-described embodiment, an example was shown in which heaters 314, 324, 414, and 424 were provided in lower plates 312 and 412 and upper plates 322 and 422, but the positions of the heaters may be changed. For example, when lower plates 312 and 412 and upper plates 322 and 422 are formed of a metal material such as stainless steel, an electric current supply device may be provided to supply electricity to lower plates 312 and 412 and upper plates 322 and 422 so that lower plates 312 and 412 and upper plates 322 and 422 themselves can function as heaters by generating heat due to electrical resistance.

[0207] Furthermore, in the above-described embodiment, hydraulic cylinders 330 and 430 are provided as the driving devices, but the driving devices are not limited to hydraulic cylinders 330 and 430. Examples of driving devices include air cylinders and diaphragms. When a diaphragm is used, a stage may be used that includes a diaphragm as a film that covers the airtight space and a plate that is provided on the diaphragm via an appropriate member such as a heat insulating material. By injecting gas or liquid into the airtight space, pressure can be applied by the plate supported by the diaphragm.

[0208] <Explanation of circuit board manufacturing method> A circuit board can be manufactured using the above-described method for manufacturing a laminate. A method for manufacturing a circuit board according to one embodiment of the present invention includes the steps of manufacturing a laminate using the manufacturing method according to the above-described embodiment and curing the prepreg of the laminate. By curing the prepreg, a cured prepreg can be formed. Thus, a circuit board including the circuit board and the cured prepreg can be manufactured. The cured prepreg usually has a low dielectric loss tangent Df as described above, and can therefore function as, for example, an insulating layer or a sealing layer.

[0209] The prepreg is usually cured by heat curing. The heat curing conditions for the prepreg may vary depending on the composition of the resin composition. For example, the curing temperature is preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. The curing time is preferably 5 to 120 minutes, more preferably 10 to 100 minutes, and even more preferably 15 to 100 minutes.

[0210] The method for producing a circuit board may include preheating the prepreg at a temperature lower than the curing temperature before thermally curing the prepreg. For example, prior to thermally curing the prepreg, the prepreg may be preheated at a temperature of typically 50°C to 150°C, preferably 60°C to 140°C, and more preferably 70°C to 130°C for typically 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes.

[0211] The method for producing a circuit board may include a step of peeling off the support from the resin sheet piece. The peeling off of the support may be performed before or after curing the prepreg.

[0212] The method for manufacturing a circuit board may include a step of forming holes such as via holes or through holes in the cured product after curing the prepreg to form a cured product. The method for forming the holes may be selected depending on factors such as the composition of the resin composition. For example, holes may be formed by processing methods such as drilling, laser processing, and plasma processing, with laser processing being preferred. For example, holes may be formed by irradiating the cured product with laser light after peeling off the support, or by irradiating the cured product with laser light through the support. The dimensions and shape of the holes may be determined appropriately depending on the design of the circuit board.

[0213] The method for manufacturing a circuit board may include a step of subjecting the cured product to a roughening treatment. The roughening treatment can roughen the surface of the cured product. Furthermore, the roughening treatment can remove smears (resin residues) from the cured product. Therefore, this roughening treatment is sometimes called a "desmear treatment." For example, when holes are formed in a cured product, smears may form in the holes. Therefore, it is preferable to perform the roughening treatment after the hole formation step to remove the smears.

[0214] The procedure and conditions for the roughening treatment are not particularly limited, and any known procedure and conditions that can be used when forming an insulating layer for a circuit board may be adopted. For example, the roughening treatment may be performed by subjecting the cured product to a swelling treatment using a swelling liquid, an oxidation treatment using an oxidizing agent, and a neutralization treatment using a neutralizing liquid in this order.

[0215] Examples of swelling liquids used in the roughening treatment include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Sodium hydroxide solution and potassium hydroxide solution are more preferred as alkaline solutions. Commercially available swelling liquids include "Swelling Dip Securiganth P" and "Swelling Dip Securiganth SBU" manufactured by Atotech Japan. Swelling treatment with a swelling liquid can be performed, for example, by immersing the cured product in the swelling liquid at 30°C to 90°C for 1 to 20 minutes. To keep the swelling of the resin in the cured product to an appropriate level, it is preferable to immerse the cured product in the swelling liquid at 40°C to 80°C for 5 to 15 minutes.

[0216] Examples of oxidizing agents used in the roughening treatment include alkaline permanganate solutions prepared by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. Oxidation treatment using an oxidizing agent such as alkaline permanganate solution is preferably carried out by immersing the cured material in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigance P" manufactured by Atotech Japan.

[0217] The neutralizing solution used in the roughening treatment is preferably an acidic aqueous solution, and a commercially available product such as "Reduction Solution Securigant P" manufactured by Atotech Japan can be cited as an example. Neutralization treatment using a neutralizing solution can be carried out by immersing the surface that has been oxidized with an oxidizing agent in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the standpoint of workability, a preferred method is to immerse the object that has been oxidized with an oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

[0218] The method for producing a circuit board may include a step of forming a conductor layer on the cured product. When the method for producing a circuit board includes a step of forming holes or a step of performing a roughening treatment, the step of forming the conductor layer is usually preferably performed after the step of forming holes or the step of performing a roughening treatment.

[0219] The conductive material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor layer may be a single metal layer or an alloy layer. Examples of alloy layers include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys). Among these, from the viewpoints of versatility in forming the conductor layer, cost, ease of patterning, and the like, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy is preferred. A single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy, is more preferred, and a single metal layer of copper is even more preferred.

[0220] The conductor layer may have a single layer structure, or a multi-layer structure including two or more single metal or alloy layers made of different types of metals or alloys. When the conductor layer has a multi-layer structure, the layer in contact with the cured prepreg is preferably a single metal layer of chromium, zinc, or titanium, or an alloy layer of a nickel-chromium alloy.

[0221] The thickness of the conductor layer depends on the design of the circuit board, but is preferably 3 μm to 35 μm, and more preferably 5 μm to 30 μm.

[0222] The conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the cured product using a conventionally known technique such as a semi-additive method or a full-additive method. From the viewpoint of ease of production, the semi-additive method is preferred. An example of forming a conductor layer by a semi-additive method will be described below.

[0223] First, an electroless plated layer (plating seed layer) is formed on the surface of the cured prepreg by electroless plating. Next, a mask pattern is formed on the formed electroless plated layer, exposing a portion of the electroless plated layer corresponding to the desired wiring pattern. After forming an electroless plated layer on the exposed electroless plated layer by electrolytic plating, the mask pattern is removed. Thereafter, unnecessary electroless plated layer is removed by etching, forming a conductor layer having the desired wiring pattern.

[0224] When a conductor layer is formed on the cured product, the method for producing a circuit board may include annealing the conductor layer after the formation of the conductor layer. Annealing can improve the adhesion between the cured product and the conductor layer. The annealing can be performed, for example, by heating at 150°C to 210°C for 20 to 180 minutes.

[0225] In the method for producing a circuit board, each of the above steps may be performed only once or may be repeated two or more times. For example, the above steps may be repeated to form a circuit board having a multilayer structure, such as a multilayer printed wiring board having a plurality of insulating layers and conductor layers formed from a cured product of prepreg.

[0226] The method for manufacturing a circuit board may further include any optional steps in addition to the steps described above. For example, the method for manufacturing a circuit board may include a step of providing a semiconductor chip so that the semiconductor chip is bonded to the conductor layer. Specifically, when manufacturing a circuit board for a semiconductor chip package including a semiconductor chip, the method for manufacturing a circuit board may include a step of providing the semiconductor chip. The semiconductor chip may be bonded under appropriate conditions that allow conductive connection between the terminal electrodes of the semiconductor chip and the conductor layer formed on the cured prepreg. For example, conditions used in flip-chip mounting may be employed. The semiconductor chip may be bonded via an insulating adhesive or by reflow bonding. If necessary, the provided semiconductor chip may be filled with a mold underfill material. The method for manufacturing a circuit board may also include, for example, a step of forming a sealing layer, a step of forming a solder resist layer, and a step of dicing the manufactured circuit board into individual pieces.

[0227] Examples of circuit boards include printed wiring boards and semiconductor chip packages. Examples of semiconductor chip packages include FC-CSP, MIS-BGA package, ETS-BGA package, fan-out type WLP (Wafer Level Package), fan-in type WLP, fan-out type PLP (Panel Level Package), and fan-in type PLP. In these semiconductor chip packages, it is preferable to form a rewiring formation layer as an insulating layer using a cured product obtained by curing the above-mentioned resin composition. However, the circuit board is not limited to those exemplified here.

[0228] <Description of semiconductor device> The circuit board can be used to manufacture a semiconductor device. The semiconductor device includes the circuit board described above. Examples of semiconductor devices include various semiconductor devices used in electrical appliances (e.g., computers, mobile phones, smartphones, tablet devices, wearable devices, digital cameras, medical equipment, televisions, etc.) and vehicles (e.g., motorcycles, automobiles, trains, ships, aircraft, etc.). The semiconductor device may be manufactured by a manufacturing method including, for example, a step of manufacturing a circuit board by the method described above and a step of providing the circuit board on the semiconductor device. [Example]

[0229] The present invention will be specifically described below with reference to examples, although the present invention is not limited to these examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Unless otherwise specified, the temperature and pressure conditions were room temperature (23°C) and atmospheric pressure (1 atm).

[0230] Example 1 (1) Production of Resin Varnish A: Bisphenol epoxy resin (Nippon Steel Chemical Co., Ltd. "ZX1059", epoxy equivalent: approximately 165 g / eq.) 15 parts, tetramethylbisphenol epoxy resin (Mitsubishi Chemical Co., Ltd. "YX4000H", epoxy equivalent: 194 g / eq.) 10 parts, biphenylaralkyl epoxy resin (Nippon Kayaku Co., Ltd. "NC3000L", epoxy equivalent: approximately 271 g / eq.) 18 parts, naphthalene epoxy resin (DIC Corporation "HP4710", epoxy equivalent: approximately 170 g / eq.) 5 parts, phenoxy resin (Mitsubishi Chemical Corporation "YL7553BH30", MEK and cyclohexane solution with 30% solids) 10 parts, phenolic hardener with triazine skeleton and cresol novolac structure (DIC Corporation "LA-3018-50P", phenolic hydroxyl group equivalent: approximately 151 g / eq., 50% solids solution in 2-methoxypropanol) 5 parts, activated ester resin (DIC Corporation "HP-C-8000-65T", active ester group equivalent weight approximately 223 g / eq., toluene solution with a solid content of 60%) 30 parts, imidazole-based reaction accelerator (Shikoku Chemical Industry Co., Ltd. "1B2PZ", MEK solution with a solid content of 5% by mass) 3 parts, methyl ethyl ketone (MEK) 30 parts, organic filler (Aica Kogyo Co., Ltd. "AC3816N") 6 parts, and inorganic filler (Admatechs Co., Ltd. "SO-C2", surface-treated with an amino-based silane coupling agent (Shin-Etsu Chemical Co., Ltd. "KBM573", N-phenyl-3-aminopropyltrimethoxysilane) with a surface treatment amount of 0.6% by mass of amino-based silane coupling agent relative to 100% by mass of inorganic filler, average particle size 0.5 μm, specific surface area 5.8 m 2 130 parts of the resin composition (1 / g) was dispersed uniformly using a mixer to prepare Resin Varnish A as a liquid resin composition.

[0231] (2) Prepreg manufacturing: The obtained resin varnish A was applied to a fiber substrate (glass cloth, manufactured by Nitto Boseki Co., Ltd., "Style WEA1017", number of filaments per yarn: 50, warp density: 95 / 25 mm, weft density: 95 / 25 mm, cloth mass: 19 g / m 2A prepreg was produced by impregnating a 13 μm thick fiber sheet with a surface treatment amount of 0.2% by mass with the resin composition and drying it in a vertical drying oven at 105°C for 5 minutes. The content of the resin composition in the prepreg relative to 100% by mass of the prepreg was calculated from the mass of the produced prepreg and the mass of the fiber substrate in the prepreg, and the content of the resin composition in the prepreg relative to 100% by mass of the prepreg was found to be 75% by mass. The thickness of the prepreg was 35 μm. The prepreg was rectangular when viewed in the thickness direction, with a length in the vertical direction of 30 cm and a length in the horizontal direction of 20 cm.

[0232] (3) Production of resin sheet pieces: A PET film ("AL5" manufactured by Lintec Corporation, thickness 38 μm) was prepared as a support. It had a release side with a release agent layer and a non-release side without a release agent layer. Supports were placed on both sides of the prepreg so that the release agent layer was in contact with the prepreg. The prepreg was then laminated using a batch-type vacuum pressure laminator (a two-stage build-up laminator "CVP700" manufactured by Nikko Materials Co., Ltd.). The lamination was performed by reducing the pressure to 5 hPa or less for 30 seconds, and then pressing at 150 °C and a pressure of 0.7 MPa for 300 seconds. This lamination process yielded a resin sheet with a support / prepreg / support layer structure. The resin sheet was cut parallel to the weft yarns to obtain a resin sheet piece with prepreg formed over the entire longitudinal direction of the support (step (VI)). Both longitudinal ends of this resin sheet piece had a flush surface that included the end face of the support and the end face of the prepreg.

[0233] (4) Laminating the resin sheet pieces: An inner layer substrate (Panasonic Electric Works "R1515A", copper layer thickness 18 μm, substrate thickness 0.8 mm) with copper layers on both sides was prepared. The copper layer of this inner layer substrate was etched to form a comb-tooth pattern with a wiring width of 170 μm and wiring spacing of 180 μm. The arithmetic surface roughness Ra of the copper layer on which the comb-tooth pattern was formed was measured using a non-contact surface roughness meter (Bruker WYKO GT-3X), and was found to be 100.0 nm.

[0234] One of the supports was peeled off from the resin sheet piece to expose the prepreg. Resin sheet pieces were placed on both sides of the inner layer substrate so that the prepreg on the resin sheet piece contacted the copper layer on the inner layer substrate with the comb-tooth pattern formed thereon, and then placed on the carrier film of a batch-type vacuum pressure laminator (a two-stage build-up laminator "CVP700" manufactured by Nikko Materials Co., Ltd.). The resin sheet piece and inner layer substrate were placed so that the warp yarns of the fiber substrate in the prepreg were parallel to the carrier direction (MD) of the carrier film. This resulted in a stack of the carrier film, support, prepreg, inner layer substrate, prepreg, support, and carrier film in this order.

[0235] The resin sheet piece and the inner layer substrate were fed to the first stage of the laminator by a carrier film (step (I)). In the first stage, the resin sheet piece was laminated on both sides of the inner layer substrate (step (II)). This lamination was carried out by reducing the pressure for 30 seconds to 5 hPa or less, and pressing at 150°C and a pressure of 0.7 MPa for 300 seconds.

[0236] The resin sheet pieces and the inner layer substrate were then transported to the second stage by a carrier film (step (III)). In the second stage, the resin sheet pieces and the inner layer substrate were subjected to a planarization treatment to obtain a laminate (step (IV)). The planarization treatment was carried out by heat pressing at 120°C and a pressure of 0.5 MPa for 90 seconds. The laminate was then removed from the carrier film (step (V)).

[0237] (5) Measurement of minimum melt viscosity X before vacuum lamination process: The support was peeled off from a piece of resin sheet before lamination with the inner layer substrate to obtain a prepreg. Twenty circular prepreg pieces with a diameter of 18 mm were cut from this prepreg. These 20 prepreg pieces were stacked to obtain a measurement sample. The minimum melt viscosity of the obtained measurement sample was measured using a dynamic viscoelasticity measuring device (Rheosol-G3000, manufactured by UBM Corporation). Specifically, the dynamic viscoelastic modulus was measured by heating the sample from a starting temperature of 60°C to 200°C, and the minimum melt viscosity (poise) was calculated. The measurement conditions were a heating rate of 5°C / min, a temperature interval of 2.5°C, a frequency of 1 Hz, and a strain of 1 deg. The obtained minimum melt viscosity represented the minimum melt viscosity X (poise) before the vacuum lamination process.

[0238] (6) Measurement of minimum melt viscosity Y after vacuum lamination process: The resin sheet pieces before being laminated with the inner layer substrate were subjected to a pressing process (lamination process) in which heat was applied in a reduced pressure environment under the same conditions as the lamination in the first stage of "(4) Lamination of resin sheet pieces" described above. The support was then peeled off from the resin sheet pieces to obtain prepreg. Twenty circular prepreg pieces with a diameter of 18 mm were cut from this prepreg. The minimum melt viscosity was measured using these 20 prepreg pieces using the same method as in "(5) Measurement of minimum melt viscosity X before vacuum lamination process" described above. The obtained minimum melt viscosity represents the minimum melt viscosity Y (poise) after the vacuum lamination process.

[0239] The minimum melt viscosity X of the prepreg measured in Example 1 was 700 poise, and the minimum melt viscosity Y was 860 poise, so the ratio Y / X was 1.23.

[0240] <Example 2> A laminate was produced in the same manner as in Example 1, except that the lamination conditions in the first stage were changed to reduce the pressure to 5 hPa or less for 30 seconds, and pressing at 150°C and a pressure of 0.7 MPa for 900 seconds. The minimum melt viscosity X of the prepreg measured in Example 2 was 700 poise, the minimum melt viscosity Y was 8000 poise, and the ratio Y / X was 11.43.

[0241] Example 3 The fiber base material was a glass cloth "Style WEA1024" manufactured by Nitto Boseki Co., Ltd. (100 filaments per thread, warp density 90 / 25 mm, weft density 90 / 25 mm, fabric mass 22 g / m 2 A laminate was produced in the same manner as in Example 1, except that the thickness of the fiber substrate was changed to 24 μm and the surface treatment amount was changed to 0.2% by mass. Due to the change in the thickness of the fiber substrate, the thickness of the prepreg became 40 μm. The minimum melt viscosity X of the prepreg measured in Example 3 was 700 poise, the minimum melt viscosity Y was 860 poise, and the ratio Y / X was 1.23.

[0242] Example 4 A laminate was produced in the same manner as in Example 1, except that the lamination conditions in the first stage were changed to reduce the pressure to 5 hPa or less for 30 seconds, and pressing at 130°C and a pressure of 0.7 MPa for 300 seconds. The minimum melt viscosity X of the prepreg measured in Example 4 was 900 poise, the minimum melt viscosity Y was 1500 poise, and the ratio Y / X was 1.67.

[0243] <Example 5> Preparation of Resin Composition B: The amount of a phenolic curing agent having a triazine skeleton and a cresol novolac structure (DIC Corporation's "LA-3018-50P," phenolic hydroxyl group equivalent weight approximately 151 g / eq., 50% solids solution in 2-methoxypropanol) was changed to 15 parts. Also, 30 parts of an activated ester resin (DIC Corporation's "HP-C-8000-65T," toluene solution with a 60% solids content) was replaced with 15 parts of a naphthol aralkyl phenolic resin (Nippon Steel Chemical Corporation's "SN-485," phenolic hydroxyl group equivalent weight approximately 223 g / eq) in MEK with a 60% solids content. Resin varnish B was produced as a resin composition using the same method as in "(1) Production of resin varnish A" in Example 1, except for the above changes.

[0244] A laminate was produced in the same manner as in Example 1, except that resin varnish B was used instead of resin varnish A. The minimum melt viscosity X of the prepreg measured in Example 5 was 900 poise, the minimum melt viscosity Y was 1500 poise, and the ratio Y / X was 1.67.

[0245] Example 6 After impregnating the fiber substrate with resin varnish A, the fiber substrate was squeezed before drying to adjust the amount of resin varnish, thereby changing the prepreg thickness to 40 μm and the resin composition content in the prepreg to 77.0 mass%. Furthermore, the surface of the copper layer of the inner layer substrate before lamination was treated with an etching agent under conditions different from those in Example 1, changing the arithmetic surface roughness Ra of the copper layer on which the comb-tooth pattern was formed to 220.0 nm. Except for the above, a laminate was produced using the same method as in Example 1. The minimum melt viscosity X of the prepreg measured in Example 6 was 900 poise, and the minimum melt viscosity Y was 1500 poise, with the ratio Y / X being 1.67.

[0246] <Comparative Example 1> After impregnating the fiber substrate with resin varnish A, the fiber substrate was squeezed before drying to adjust the amount of resin varnish, thereby changing the resin composition content in the prepreg to 77.0% by mass. The lamination conditions in the first stage were also changed: the pressure was reduced for 30 seconds to 5 hPa or less, and pressing was performed at 120°C and a pressure of 0.7 MPa for 60 seconds. Except for the above, a laminate was produced using the same method as in Example 1. The minimum melt viscosity X of the prepreg measured in Comparative Example 1 was 700 poise, the minimum melt viscosity Y was 750 poise, and the ratio Y / X was 1.07.

[0247] <Comparative Example 2> A laminate was produced in the same manner as in Example 1, except that the lamination conditions in the first stage were changed to reduce the pressure to 5 hPa or less for 30 seconds, and pressing at 150°C and a pressure of 0.7 MPa for 1800 seconds. The minimum melt viscosity X of the prepreg measured in Comparative Example 2 was 900 poise, the minimum melt viscosity Y was 12000 poise, and the ratio Y / X was 13.33.

[0248] <Reference example 1> In order to confirm that exposure of filaments from the end of a prepreg is a problem that occurs specifically when a fiber base material with a low filament density is used, the following Reference Example 1 was carried out.

[0249] The fiber base material was a glass cloth "Style WEA1078" manufactured by Nitto Boseki Co., Ltd. (200 filaments per thread, warp density 54 / 25mm, weft density 54 / 25mm, fabric mass 42g / m 2 A laminate was produced in the same manner as in Example 1, except that the thickness was changed to 45 μm and the surface treatment amount was changed to 0.2% by mass. The minimum melt viscosity X of the prepreg measured in Reference Example 1 was 700 poise, the minimum melt viscosity Y was 880 poise, and the ratio Y / X was 1.26.

[0250] <Method for evaluating filament exposure from the edge of prepreg> The outer periphery of the produced laminate was visually observed to determine whether or not there was any exposed filament (fluffing) protruding from the area covered by the support. "Good": No exposed filament. "Poor": Filament is exposed.

[0251] <Method for evaluating the flatness of prepreg after lamination> The support was peeled off from the produced laminate. The height of the surface of the prepreg on the copper layer on which the comb-tooth pattern was formed was measured. The height measurement was performed using a non-contact surface roughness meter (VYKO GT-X3 manufactured by Veeco Instruments) in VSI mode with a 50x lens, with a measurement area of ​​121 μm × 92 μm. The undulation (μm) was calculated by subtracting the minimum height from the maximum height. Measurements were performed at three randomly selected locations excluding a range of 5% of the prepreg dimensions from the edge of the prepreg, and the average of the measurements from the three locations was evaluated according to the following criteria. The undulation is the difference between the maximum and minimum heights on the prepreg surface; the smaller the value, the better the flatness. "Good": Average undulation is less than 2 μm. "Poor": Undulation is 2 μm or more.

[0252] <Void measurement method> The support was peeled off from the produced laminate. Three locations (each 3 cm × 3 cm) on the surface of the prepreg on the copper layer on which the comb tooth pattern was formed were observed using a microscope (KEYENCE VHX-7000), and voids were evaluated according to the following criteria. "Good": No voids in the entire observation area. "Poor": Voids present in one or more of the entire observation area.

[0253] <Result> The results of the above-mentioned Examples, Comparative Examples and Reference Examples are shown in the following table. In the table, the meanings of the abbreviations are as follows: "Yarn count": The number of yarns per inch in the TD direction of the fiber substrate in the prepreg. "Number of filaments per yarn": The number of filaments per yarn of the fiber substrate in the prepreg. "Number of filaments per inch": The number of filaments per inch in the TD direction of the fiber substrate in the prepreg. "Resin composition content": The content of the resin composition relative to 100% by mass of the prepreg. "Substrate roughness": The arithmetic mean roughness of the copper foil surface of the inner layer substrate.

[0254] [Table 1]

[0255] [Table 2] [Explanation of symbols]

[0256] 1. Laminator 10 Resin sheet piece 11,12 MD end face of resin sheet piece 20 Long resin sheet 30 Cutting device 40 Support 50 laminate 100, 100a, 100b support 100U Support surface 200, 200a, 200b prepreg 200E Prepreg end in MD direction 210 Fiber base material 220 Resin composition 230 warp threads 231 Filament 240 weft threads 241 Filament 300 First Stage 310 Lower press material 310U Pressing surface 311 Lower support material 311U support surface 312 Lower Plate 312U Top of bottom plate 313 Lower frame material 314 Heater 315 Elastic Members 316 Fixed frame part 317 Movable frame part 318 Elastic support part 320 Upper press material 320D pressing surface 321 Upper support material 321D Support surface 322 Upper Plate 322D Lower surface of upper plate 323 Upper frame material 324 Heater 325 Elastic Members 326 Nozzle 330 Hydraulic Cylinder 331 Piston rod 400 Second Stage 410 Lower Press Material 410U Pressing surface 411 Lower support material 411U Support surface 412 Lower Plate 412U Top of bottom plate 413 Lower frame material 414 Heater 415 Elastic Members 416 Fixed frame part 417 Movable frame part 418 Elastic support part 420 Upper press material 420D pressing surface 421 Upper support material 421D Support surface 422 Upper Plate 422D Underside of upper plate 423 Upper frame material 424 Heater 425 Elastic Members 426 Nozzle 430 Hydraulic Cylinder 431 Piston rod

Claims

1. A method for producing a laminate, comprising laminating a resin sheet piece having a support and a prepreg with an inner layer substrate using a laminator to produce a laminate; The prepreg includes a fiber substrate including a plurality of filaments and a resin composition impregnated in the fiber substrate and including a thermosetting resin; The laminator a first stage capable of laminating an inner layer substrate and a prepreg; A second stage that can flatten the prepreg; a carrier film capable of transporting the inner layer substrate and the resin sheet piece in the order of the first stage and the second stage; Provided with: The manufacturing method comprises: a step (I) of supplying a resin sheet piece and an inner layer substrate to a first stage to obtain a state in which a carrier film, a support, a prepreg, and an inner layer substrate are stacked in this order; In a first stage, a step (II) of pressing the resin sheet piece and the inner layer substrate while applying heat in a reduced pressure environment; A step (III) of transporting the resin sheet piece and the inner layer substrate to a second stage by a transport film; In a second stage, the resin sheet piece and the inner layer substrate are pressed together while being heated to obtain a laminate (IV); (V) a step of removing the laminate from the carrier film; in this order; The fiber substrate has less than 10,000 filaments per inch in the TD direction; the ratio Y / X of the minimum melt viscosity X of the prepreg before step (II) to the minimum melt viscosity Y of the prepreg after step (II) and before step (IV) is greater than 1.2; A method for producing a laminate, wherein the minimum melt viscosity Y is less than 10,000 poise.

2. the inner layer substrate has a conductor layer exposed on a surface facing the resin sheet piece, The method for producing a laminate according to claim 1 , wherein the conductor layer has an arithmetic mean roughness of 250 nm or less.

3. The resin composition includes a polymeric resin compatible with a thermosetting resin; The method for producing a laminate according to claim 1 , wherein the amount of the polymer resin is 10% by mass or less relative to 100% by mass of the resin component of the resin composition.

4. The resin composition includes an inorganic filler; The method for producing a laminate according to claim 1, wherein the amount of the inorganic filler is 50% by mass or more relative to 100% by mass of the nonvolatile components of the resin composition.

5. The method for producing a laminate according to claim 1, wherein the minimum melt viscosity X is 5,000 poise or less.

6. The method for producing a laminate according to claim 1, wherein in step (I), the prepreg is formed over the entire support in the MD direction.

7. The method for producing a laminate according to claim 1, further comprising, prior to the step (I), a step (VI) of cutting the long resin sheet comprising the support and the prepreg to obtain resin sheet pieces.

8. The method for producing a laminate according to claim 1 , wherein the prepreg has a thickness of 100 μm or less.

9. A step of producing a laminate by the production method according to any one of claims 1 to 8; and curing the prepreg.

Images