Laminate and metal-clad laminate using same

Abstract

To provide a laminated plate with excellent permittivity, dielectric loss tangent and permittivity uniformity, as well as low thermal expansion coefficient and excellent heat resistance.SOLUTION: A laminated plate includes: a core layer including at least one first resin layer in which a first matrix resin is impregnated or applied on glass fiber cloth; and a surface layer laminated on one or both sides of the core layer and including at least one second resin layer in which a second matrix resin is impregnated or applied on organic fiber cloth. A thermal expansion coefficient of the second resin layer is greater than that of the first resin layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a laminate and a metal-clad laminate using the same. [Background technology]

[0002] In recent years, with the remarkable progress in information network technology and the expansion of services utilizing information networks, electronic devices are being required to handle larger amounts of information and to process faster. To meet these demands, printed wiring boards mounted on electronic devices are strongly required to have low dielectric constants and low dielectric loss tangents in addition to the traditional properties of insulation reliability, heat resistance, rigidity, flame retardancy, etc. Therefore, further improvements in the dielectric constants and dielectric loss tangents of resin compositions (hereinafter also referred to as "matrix resin compositions") and glass cloths, which are the main insulating materials constituting printed wiring boards, are being investigated.

[0003] As a matrix resin composition, a mixture containing polyphenylene ether (hereinafter also referred to as "PPE"), which has a low dielectric constant, dielectric dissipation factor, and high heat resistance, and other resins is suitably used as the material for the above-mentioned printed wiring board. For example, Patent Document 1 describes that a resin composition containing a specific modified polyphenylene ether, a specific cyanurate compound as a crosslinking agent, a copolymer of butadiene and styrene, and an organic peroxide in predetermined proportions can provide a matrix resin composition with excellent low dielectric constant and low dielectric dissipation factor.

[0004] As the glass cloth, low-dielectric-constant glass cloth such as NE glass or L glass, which has a composition different from that of general E glass, is preferably used. Generally, to lower the dielectric constant, it is necessary to increase the amount of SiO2 and B2O3 contained in the glass composition. To date, low-dielectric-constant glass compositions actually used in glass cloth for printed wiring boards have often been adjusted to contain SiO2 in an amount of 45% to 60% by mass and B2O3 in an amount of 15% to 30% by mass (Patent Documents 2 and 3). Meanwhile, the use of organic fiber cloth as a low-dielectric-constant substrate other than glass cloth has been investigated (Patent Documents 4 and 5). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-82200 A [Patent Document 2] Japanese Patent Application Publication No. 63-2831 [Patent Document 3] Japanese Patent Application Publication No. 11-292567 [Patent Document 4] Special Publication No. 2017-502179 [Patent Document 5] Japanese Patent Application Laid-Open No. 2008-069478 [Non-patent literature]

[0006] [Non-Patent Document 1] Kono Kenya, Naka Yasuhiro, Tanie Takashi, Kimoto Ryosuke, Yamamoto Kenichi, "Fatigue Life Prediction Method for Solder Joints Considering High-Temperature Degradation," Journal of the Japan Institute of Electronics Packaging, 17(2), 2014, pp. 123-131 Summary of the Invention [Problem to be solved by the invention]

[0007] However, signal skew (skew) is becoming a significant issue in future high-speed transmissions of 200 Gbps or more. This problem is primarily due to local variations in the dielectric constant of the insulating layer of a substrate. While the dielectric constant of a typical low-dielectric-constant matrix resin composition is approximately 2.0 to 3.0, that of low-dielectric-constant glass cloth is approximately 4.6 to 4.8. Local variations in the dielectric constant of low-dielectric-constant glass cloth within a substrate are becoming a major problem. Furthermore, even when organic fiber cloth is used, as described in Patent Documents 4 and 5, sufficient low thermal expansion coefficients and heat resistance for cloth, prepregs, and laminates cannot be achieved. Thus, when a prepreg or laminate is produced by combining a low-dielectric-constant resin composition with a low-dielectric-constant glass cloth, the dielectric constant uniformity of the insulating layer required for high-speed transmission cannot be achieved. Even when organic fiber cloth is used, sufficient low thermal expansion coefficients and heat resistance for cloth, prepregs, and laminates cannot be achieved.

[0008] An object of the present disclosure is to provide a laminate having excellent dielectric constant, dielectric loss tangent, and dielectric constant uniformity, as well as a low coefficient of thermal expansion and excellent heat resistance. [Means for solving the problem]

[0009] The inventors have found that in a laminate having a core layer including a first resin layer having a glass fiber cloth and a surface layer including a second resin layer having an organic fiber cloth, the above-mentioned problems can be solved by making the thermal expansion coefficient of the second resin layer larger than the thermal expansion coefficient of the first resin layer. Examples of embodiments of the present disclosure are listed in the following items [1] to

[19] . [1] a core layer including at least one first resin layer in which a glass fiber cloth is impregnated or coated with a first matrix resin; a surface layer laminated on one or both sides of the core layer and including at least one second resin layer in which a second matrix resin is impregnated or coated on an organic fiber cloth; A laminate comprising: A laminate in which the thermal expansion coefficient of the second resin layer is greater than the thermal expansion coefficient of the first resin layer. [2] Item 2. The laminate according to item 1, wherein the thermal expansion coefficient of the first resin layer is 3 ppm / °C or more and less than 20 ppm / °C, and the thermal expansion coefficient of the second resin layer is 18 ppm / °C or more and 200 ppm / °C or less. [3] 3. The laminate according to item 1 or 2, wherein the surface layers are laminated on both sides of the core layer. [4] 4. The laminate according to any one of items 1 to 3, wherein the fibers of the organic fiber cloth are fibers made of a resin composition containing polyphenylene ether. [5] 5. The laminate according to item 4, wherein the resin composition containing polyphenylene ether comprises 5% by mass to 95% by mass of polyphenylene ether and 5% by mass to 95% by mass of at least one selected from liquid crystal polyester and syndiotactic polystyrene, based on the total mass of the resin composition. [6] 6. The laminate according to any one of items 1 to 5, wherein the thermal expansion coefficient of the first resin layer is 3 ppm / °C or more and less than 20 ppm / °C, and the thermal expansion coefficient of the second resin layer is 20 ppm / °C or more and 150 ppm / °C or less. [7] 7. The laminate according to any one of items 1 to 6, wherein the core layer includes two or more of the first resin layers. [8] 8. The laminate according to any one of items 1 to 7, wherein the number of layers of the first resin layer included in the core layer is greater than the number of layers of the second resin layer included in the surface layer. [9] 9. The laminate according to any one of items 1 to 8, wherein the second matrix resin contained in the surface layer has a dielectric constant of 2.0 or more and 3.0 or less, and the organic fiber cloth has a dielectric constant of 2.0 or more and 3.0 or less.

[10] A metal-clad laminate comprising the laminate according to any one of items 1 to 9 and a metal foil laminated on the surface layer of the laminate.

[11] a step of laminating at least one first prepreg obtained by impregnating or coating a glass fiber cloth with a first matrix resin and at least one second prepreg obtained by impregnating or coating an organic fiber cloth with a second matrix resin to prepare a prepreg laminate comprising a core layer including the at least one first prepreg and surface layers including the at least one second prepreg laminated on one or both sides of the core layer; curing the first matrix resin and the second matrix resin; A method for manufacturing a laminate, comprising: The method for producing a laminate, wherein the second prepreg has a larger thermal expansion coefficient than the first prepreg.

[12] Item 12. The method according to item 11, wherein the first prepreg has a thermal expansion coefficient of 3 ppm / °C or more and less than 20 ppm / °C, and the second prepreg has a thermal expansion coefficient of 18 ppm / °C or more and 200 ppm / °C or less.

[13] 13. The method according to item 11 or 12, wherein the surface layers are laminated on both sides of the core layer.

[14] 14. The method according to any one of items 11 to 13, wherein the fibers of the organic fiber cloth are fibers made of a resin composition containing polyphenylene ether.

[15] Item 15. The method according to Item 14, wherein the resin composition containing polyphenylene ether comprises 5% by mass to 95% by mass of polyphenylene ether and 5% by mass to 95% by mass of at least one selected from liquid crystal polyester and syndiotactic polystyrene, based on the total mass of the resin composition.

[16] 16. The method according to any one of items 11 to 15, wherein the first prepreg has a thermal expansion coefficient of 3 ppm / °C or more and less than 20 ppm / °C, and the second prepreg has a thermal expansion coefficient of 20 ppm / °C or more and 150 ppm / °C or less.

[17] 17. The method according to any one of items 11 to 16, wherein two or more layers of the first prepreg are laminated onto the core layer.

[18] 18. The method according to any one of items 11 to 17, wherein the number of layers of the first prepreg laminated on the core layer is greater than the number of layers of the second prepreg laminated on the surface layer.

[19] 19. The method according to any one of items 11 to 18, wherein the dielectric constant of the second matrix resin contained in the surface layer is 2.0 or more and 3.0 or less, and the dielectric constant of the organic fiber cloth is 2.0 or more and 3.0 or less. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a laminate having an excellent dielectric constant, dielectric loss tangent, and dielectric constant uniformity, as well as an excellent low coefficient of thermal expansion and heat resistance. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing a cross section of a laminated plate according to the present disclosure. [Figure 2] FIG. 2 is a schematic diagram showing a cross section of a laminated plate according to the present disclosure. [Figure 3] FIG. 3 is a schematic diagram showing a cross section of a laminated plate according to the present disclosure. [Figure 4] FIG. 4 is a schematic diagram showing a cross section of a laminated plate according to the present disclosure. [Figure 5] FIG. 5 is a schematic diagram showing a cross section of a metal-clad laminate of the present disclosure. [Figure 6] FIG. 6 is a schematic diagram showing the laminate structure of a laminate for a temperature cycle test by computer simulation according to an embodiment. [Figure 7] FIG. 7 is a schematic diagram showing the layer structure of a laminate for evaluating electrical signal delay in the surface layer by computer simulation in an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings as necessary. In the following description of the drawings, identical or similar parts are designated by identical or similar reference numerals. However, the drawings are schematic, and the relationship between thickness and planar dimensions, etc., differs from the actual relationship. Furthermore, the embodiments shown below exemplify devices and methods for embodying the technical idea of ​​the present disclosure, and the technical idea of ​​the present disclosure does not specify the materials, shapes, structures, arrangements, etc. of the components to those described below. The technical idea of ​​the present disclosure can be modified in various ways within the technical scope defined by the claims. Furthermore, in this specification, unless otherwise specified, the symbol "to" means that the numerical values ​​at both ends are included as upper and lower limits. In this specification, the upper and lower limits of a numerical range can be arbitrarily combined.

[0013] <Laminate> The laminate disclosed herein comprises a core layer including at least one first resin layer formed by impregnating or coating a glass fiber cloth with a first matrix resin; and a surface layer laminated on one or both sides of the core layer and including at least one second resin layer formed by impregnating or coating an organic fiber cloth with a second matrix resin. The second resin layer has a thermal expansion coefficient greater than that of the first resin layer. The dielectric constant of the organic fiber cloth is closer to that of the low-dielectric-constant matrix resin than that of the glass fiber cloth, thereby reducing local variations in the dielectric constant within the laminate. By providing a second resin layer containing such organic fiber cloth as a surface layer, local variations in the dielectric constant, mainly near the surface of the laminate, are reduced, thereby reducing signal skew (skew) during high-speed transmission. Furthermore, by providing a first resin layer containing glass fiber cloth as a core layer, the laminate as a whole can achieve a sufficiently low thermal expansion coefficient and heat resistance.

[0014] The thermal expansion coefficient of the second resin layer is greater than that of the first resin layer. That is, if the thermal expansion coefficient of the first resin layer is CTE1 and the thermal expansion coefficient of the second resin layer is CTE2, then the condition CTE2 > CTE1 is satisfied. This allows the thermal expansion coefficient of the entire laminate to be equal to or greater than that of the solder, thereby alleviating strain on the solder during temperature cycling when electronic components are mounted on the laminate. If the thermal expansion coefficient of the laminate is small, the solder is compressed by both the electronic components mounted on the laminate and the laminate. However, if the thermal expansion coefficient of the laminate is equal to or greater than that of the solder, the solder is compressed by the mounted components and expanded by the laminate. This structural change alleviates strain on the solder during temperature cycling, extending the reliability life of the solder cracks and improving temperature cycle reliability. CTE2 is preferably 10 times or less than CTE1, more preferably 8 times or less than CTE1, even more preferably 6 times or less than CTE1, and particularly preferably 4 times or less than CTE1.

[0015] The core layer can have one or more first resin layers, and the surface layer can have one or more second resin layers. The laminate structure is not particularly limited as long as it has a first resin layer containing the glass fiber cloth as the core layer and a second resin layer containing an organic fiber cloth as the surface layer. For example, Figures 1 to 4 are schematic diagrams showing the cross section of a laminated plate of the present disclosure. In Figure 1, the laminated plate (100) has a core layer (10) consisting of two first resin layers (1) formed by impregnating or coating a glass fiber cloth with a first matrix resin, and a surface layer (20) laminated on both sides of the core layer (10) and consisting of one second resin layer formed by impregnating or coating an organic fiber cloth with a second matrix resin. In Figure 2, the laminated plate (100) has a core layer (10) consisting of two first resin layers (1) and a surface layer (20) laminated on one side of the core layer (10) and consisting of two second resin layers. In FIG. 3, the laminate (100) has a core layer (10) made of five first resin layers (1) and a surface layer (20) made of two second resin layers laminated on both sides of the core layer (10). In FIG. 4, the laminate (100) has a core layer (10) made of five first resin layers (1) and a surface layer (20) made of two second resin layers laminated on one side of the core layer (10). By placing a surface layer containing organic fiber cloth on a core layer containing glass fiber cloth, the thermal expansion coefficient of the entire laminate can be reduced. In addition, the delay difference of electrical signals between wirings on the laminate due to variations in dielectric constant can be reduced.

[0016] To more effectively reduce the thermal expansion coefficient of the laminate, the number of first resin layers in the core layer is preferably two or more. Examples of such laminate structures are shown in Figures 1 to 4. By making the number of first resin layers in the core layer two or more, the mechanical strength of the core layer can be increased, and warping of the laminate caused by uneven dimensional changes between the core layer and the surface layer can be reduced, thereby further improving heat resistance. From a manufacturing perspective, the number of first resin layers in the core layer is preferably 80 or less. More preferably, the number of first resin layers is 2 to 80, even more preferably 4 to 64, and particularly preferably 8 to 32.

[0017] To more effectively reduce the thermal expansion coefficient of the laminate, it is preferable to satisfy the condition m / n<1, where n is the number of first resin layers in the core layer and m is the number of second resin layers in the surface layers. That is, it is preferable that the number of first resin layers included in the core layer is greater than the number of second resin layers included in the surface layers. Such a laminate structure is illustrated in Figures 3 and 4. By satisfying this condition, the thermal expansion coefficient of the core layer can be made dominant in the thermal expansion coefficient of the entire laminate, which enhances the effect of suppressing the thermal expansion of the surface layers and further reduces the thermal expansion coefficient of the laminate as a whole.

[0018] To more effectively reduce the thermal expansion coefficient of the laminate, it is preferable to laminate surface layers on both sides of the core layer. It is more preferable that the core layer and surface layers are arranged symmetrically with respect to the center line that divides the thickness of the laminate in half in the cross section of the laminate. Such a laminate structure is illustrated in Figures 1 and 3. By laminating surface layers on both sides of the core layer, it is possible to reduce the non-uniformity of dimensional change due to temperature change on both sides, thereby enabling a uniform reduction in the thermal expansion coefficient of the laminate. It is also possible to reduce warpage of the laminate caused by non-uniformity of dimensional change. By symmetrically arranging the core layer and surface layers, it is possible to reduce or eliminate the non-uniformity of dimensional change on both sides, thereby achieving a similar thermal expansion suppression effect on both sides. By achieving the same effect on both sides, it is possible to uniformly reduce the thermal expansion coefficient of the laminate. It is also possible to reduce warpage of the laminate caused by non-uniformity of dimensional change, thereby improving reliability.

[0019] The thickness of the laminate is preferably 1.0 mm or more and 8.0 mm or less, more preferably 1.2 mm or more and 6.4 mm or less, even more preferably 1.4 mm or more and 5.6 mm or less, and particularly preferably 1.6 mm or more and 4.2 mm or less. When the thickness of the laminate is within the above range, a laminate suitable for circuit boards can be obtained, with an excellent balance between mechanical strength and productivity.

[0020] The thermal expansion coefficient in the plane direction of the second resin layer forming the surface layer is preferably 8 ppm / °C to 300 ppm / °C, more preferably 14 ppm / °C to 250 ppm / °C, even more preferably 18 ppm / °C to 200 ppm / °C, and even more preferably 20 ppm / °C to 150 ppm / °C. When the thermal expansion coefficient of the second resin layer forming the surface layer is within the above range, the thermal expansion coefficient of the laminate when laminated with the core layer can be made equal to or greater than that of the solder. This can provide an effect of alleviating strain on the solder caused by temperature cycles when mounted on an electronic component. If the thermal expansion coefficient of the laminate is small, the solder will be compressed from both the electronic component mounted on the laminate and the laminate. However, if the thermal expansion coefficient of the laminate is equal to or greater than that of the solder, the solder will be compressed from the mounted component side and expanded from the laminate side. This change in structure can alleviate the strain on the solder caused by temperature cycling, extend the reliability life of the solder cracks, and more effectively improve the temperature cycle reliability.

[0021] The thermal expansion coefficient in the plane direction of the first resin layer forming the core layer is preferably 1 ppm / °C or more and 100 ppm / °C or less, more preferably 2 ppm / °C or more and 50 ppm / °C or less, and even more preferably 3 ppm / °C or more and less than 20 ppm / °C, thereby making it possible to bring the thermal expansion coefficient of the laminate closer to that of the solder and extending the reliability life of the solder crack.In this specification, unless otherwise specified, the thermal expansion coefficient refers to the average value of the linear expansion coefficient in the range of 50°C or more and 150°C or less.

[0022] The first matrix resin used in the first resin layer forming the core layer and the second matrix resin used in the second resin layer forming the surface layer may be different compositions or the same composition, and preferably are composed of the same composition. Using the same composition can improve the adhesion at the interface between the first resin layer and the second resin layer, prevent delamination due to stress between the first resin layer and the second resin layer that occurs during temperature cycling, and extend the reliable lifespan.

[0023] <Laminate manufacturing method> The method for manufacturing a laminate disclosed herein first prepares at least one first prepreg formed by impregnating or coating a glass fiber cloth with a first matrix resin, and at least one second prepreg formed by impregnating or coating an organic fiber cloth with a second matrix resin. The second prepreg has a thermal expansion coefficient greater than that of the first prepreg. The first and second prepregs are then laminated together to prepare a prepreg laminate having a core layer containing at least one first prepreg and a surface layer containing at least one second prepreg laminated on one or both sides of the core layer. The first and second matrix resins are then cured to produce a laminate. In this specification, the terms "first prepreg" and "second prepreg" before curing correspond to the terms "first resin layer" and "second resin layer" after curing.

[0024] For example, as illustrated in Figures 1 to 4, a core layer formed by laminating one or more layers of a first prepreg and a surface layer formed by laminating one or more layers of a second prepreg can be laminated in the lamination direction of the prepregs. In this case, in order to more effectively obtain the effect of reducing the thermal expansion coefficient of the laminate, it is preferable to laminate the prepregs so that the condition m / n<1 is satisfied, where n is the number of core layers and m is the number of surface layers. In the lamination direction of the prepregs, it is preferable to laminate the surface layers on both sides of the core layer, and it is more preferable to arrange them symmetrically with respect to the center line that bisects the thickness of the laminate in the cross section of the laminate. The reason for this is as described above.

[0025] The lamination method is not particularly limited, but may be, for example, a batch method, or each prepreg may be continuously supplied and continuously laminated using a vacuum laminator, a vacuum Becquerel device, or the like.

[0026] Finally, the first prepreg 201 and the second prepreg 202 that have been stacked as described above are molded under heat and pressure to obtain a laminated plate according to the present disclosure as exemplified in FIGS.

[0027] The heat treatment method is not particularly limited, but can be carried out using, for example, a hot air dryer, an infrared heater, a heating roll device, a flat platen press, etc. When a hot air dryer or an infrared heater is used, the heat treatment can be carried out without applying substantial pressure to the bonded material. When a heating roll device or a flat platen press is used, the heat treatment can be carried out by applying a predetermined pressure to the bonded material.

[0028] The temperature during the heat treatment is not particularly limited, but is preferably in a temperature range where the resin used melts but the curing reaction of the resin does not proceed too quickly. For example, when a PPE resin is used, the melting temperature is preferably 120°C or higher, more preferably 150°C or higher. Furthermore, the temperature where the curing reaction of the resin does not proceed too quickly is preferably 250°C or lower, more preferably 230°C or lower.

[0029] The heat treatment time varies depending on the type of resin used and is not particularly limited, but can be performed for, for example, 30 minutes to 180 minutes. The pressure to be applied is also not particularly limited, but is preferably, for example, 0.2 MPa to 5 MPa, and more preferably 2 MPa to 4 MPa.

[0030] The surface layer may be laminated by a build-up method, where "build-up" means laminating prepregs and repeatedly performing processes such as drilling and wiring for each layer to produce a multilayer laminate.

[0031] <First prepreg (first resin layer)> The first prepreg can be obtained by impregnating a glass cloth with a varnish containing a first matrix resin composition and a solvent (hereinafter, sometimes simply referred to as "varnish"), and then drying and removing the solvent using a hot air dryer, etc. Alternatively, the first prepreg can be obtained by applying a varnish to a glass cloth, and then drying and removing the solvent using a hot air dryer, etc.

[0032] The first matrix resin composition preferably contains a thermosetting resin as the first matrix resin, and more preferably contains a thermosetting resin and an inorganic filler. For example, a thermosetting resin that is liquid at room temperature can be used as the thermosetting resin. Alternatively, a mixture of a resin component and a curing agent component can be used as the thermosetting resin. For example, a radical polymerization type thermosetting resin such as an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, or a maleimide resin can be used as the resin component.

[0033] The first prepreg preferably uses a resin composition containing polyphenylene ether (PPE) as the first matrix resin, which can provide better low dielectric properties.

[0034] The first prepreg may use an epoxy resin as the first matrix resin, which can reduce the cost of the laminate and provide the surface layer with excellent dielectric constant, dielectric loss tangent, and dielectric constant uniformity.

[0035] The dielectric constant of the first matrix resin constituting the first prepreg is preferably 2.0 or more and 3.0 or less, more preferably 2.5 or more and 2.8 or less. When the dielectric constant of the first matrix resin is within the above range, better low dielectric properties can be obtained.

[0036] The proportion of the first matrix resin (as solids) in the first prepreg is preferably 30% by mass to 80% by mass, and more preferably 40% by mass to 70% by mass, based on the total mass of the first prepreg. Having this proportion of 30% by mass or more tends to result in better insulation reliability when the first prepreg is used for electronic substrates, etc. Having this proportion of 80% by mass or less tends to result in better mechanical properties, such as flexural modulus, when used in applications such as electronic substrates. Similarly, the proportion of the first matrix resin in the first resin layer obtained by curing the first prepreg is preferably 30% by mass to 80% by mass, and more preferably 40% by mass to 70% by mass, based on the total mass of the first resin layer.

[0037] <Second prepreg (second resin layer)> The second prepreg according to the present disclosure can be obtained by impregnating an organic fiber cloth with a varnish containing a second matrix resin composition and a solvent (hereinafter, sometimes simply referred to as "varnish"), and then drying and removing the solvent using a hot air dryer, etc. Alternatively, the second prepreg can be obtained by applying a varnish to an organic fiber cloth, and then drying and removing the solvent using a hot air dryer, etc.

[0038] The second matrix resin composition preferably contains a thermosetting resin as the second matrix resin, and more preferably contains a thermosetting resin and an inorganic filler. For example, a thermosetting resin that is liquid at room temperature can be used as the thermosetting resin. Alternatively, a mixture of a resin component and a curing agent component can be used as the thermosetting resin. For example, a radical polymerization type thermosetting resin such as an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, or a maleimide resin can be used as the resin component.

[0039] The second prepreg preferably uses a resin composition containing polyphenylene ether (PPE) as a matrix resin. By using a resin composition containing polyphenylene ether, better low dielectric properties can be obtained. In one embodiment, the second matrix resin composition contains a low-molecular-weight PPE having a number-average molecular weight of 1,000 to 4,000.

[0040] The second prepreg may use an epoxy resin as the second matrix resin, which can reduce the cost of the laminate and ensure uniformity of the dielectric constant of the surface layer.

[0041] The dielectric constant of the second matrix resin constituting the second prepreg is preferably 2.0 or more and 3.0 or less, more preferably 2.5 or more and 2.8 or less. When the dielectric constant of the second matrix resin is within the above range, the difference in dielectric constant from the organic fiber cloth can be reduced, and the difference in delay of electrical signals between wirings that occurs on the laminate due to variations in dielectric constant can be reduced.

[0042] The proportion of the second matrix resin composition (as solids) in the second prepreg is preferably 30% by mass to 80% by mass, and more preferably 40% by mass to 70% by mass, based on the total mass of the second prepreg. Having this proportion of 30% by mass or more tends to result in better insulation reliability when the second prepreg is used for electronic substrates, etc. Having this proportion of 80% by mass or less tends to result in better mechanical properties, such as flexural modulus, when used in applications such as electronic substrates. Similarly, the proportion of the second matrix resin in the second resin layer obtained by curing the second prepreg is preferably 30% by mass to 80% by mass, and more preferably 40% by mass to 70% by mass, based on the total mass of the second resin layer.

[0043] <Glass cloth> The glass cloth used in the first prepreg is not particularly limited, and known materials used in various printed wiring board materials can be appropriately selected and used depending on the intended application and performance. Specific examples include, but are not limited to, glass fibers such as E-glass, D-glass, S-glass, T-glass, spherical glass, NE-glass, L-glass, NL-glass, L2-glass, and Q-glass, and inorganic fibers other than glass such as quartz. The use of low-dielectric glass can suppress electrical signal loss and electrical signal delay when transmitting electrical signals in the direction perpendicular to the substrate.

[0044] Among these, E glass cloth, NE glass cloth, L glass cloth, NL glass cloth, L2 glass cloth, and Q glass cloth are preferred from the viewpoint of low thermal expansion and low dielectric properties. By using low dielectric glass, it is possible to suppress electrical signal loss and electrical signal delay when transmitting electrical signals in the direction perpendicular to the substrate. These glass cloths may be used alone or in combination of two or more types.

[0045] The weaving method of the cloth is not particularly limited, but known examples include plain weave, sieve weave, and twill weave, and can be appropriately selected from these known weaves depending on the intended use and performance. Glass cloths obtained by opening these or surface-treating them with a silane coupling agent or the like are also preferably used. The thickness and mass of the glass cloth are not particularly limited, but typically glass cloths of about 0.01 mm to 0.3 mm are preferably used. From the viewpoints of strength and water absorption, in particular, the cloth should have a thickness of 200 μm or less and a mass of 250 g / m. 2 The following glass cloths are preferred, and glass cloths made of glass fibers such as E glass, NE glass, L glass, NL glass, L2 glass and Q glass are more preferred.

[0046] <Organic fiber cloth> The organic fiber cloth used in the second prepreg is not particularly limited, and known organic fibers used in various printed wiring board materials can be appropriately selected and used depending on the intended use and performance. Specific examples of organic fibers include, but are not limited to, polyimide fibers, polyphenylene ether fibers, fluorine fibers, and carbon fibers. Among these, polyphenylene ether fibers are preferred from the viewpoint of low dielectric properties.

[0047] The organic fiber cloth is preferably composed of fibers (PPE composition fibers) made of a composition containing PPE. In one embodiment, the organic fiber cloth is a woven fabric woven with a warp and weft density (i.e., the weave density of both warp and weft threads) of 20 threads / inch to 90 threads / inch and an aperture ratio of 1% to 30%. In one embodiment, the PPE composition fiber preferably contains a polyphenylene ether-based resin composition containing 5% to 95% by mass of polyphenylene ether, and more preferably contains 5% to 95% by mass of at least one of liquid crystal polyester and syndiotactic polystyrene. In one embodiment, the PPE composition fiber is preferably a fiber formed by bundling 10 to 200 single yarns having a diameter of 5 μm to 50 μm.

[0048] When polyphenylene ether is used as the organic fiber, it is preferable to use a resin composition containing polyphenylene ether as the second matrix resin. This reduces the variation in dielectric constant within the prepreg, thereby reducing the delay difference of electrical signals on the wiring formed on the prepreg. Furthermore, using a resin composition containing polyphenylene ether for the organic fiber and the second matrix resin improves adhesion between the organic fiber and the second matrix resin. This prevents interfacial delamination due to stress between the organic fiber and the matrix resin that occurs with temperature cycling, thereby extending the reliability life.

[0049] The PPE contained in the PPE composition fiber preferably has a number average molecular weight of 9000 to 21000. The number average molecular weight is determined in terms of standard polystyrene by performing gel permeation chromatography (GPC) measurement and calculating the relationship between the molecular weight of a standard polystyrene sample measured under the same conditions and the elution time.

[0050] When the number-average molecular weight of the PPE is 9,000 or more, the heat resistance required for the substrate and the chemical resistance to solvents for matrix resin composition varnishes and cleaning solutions for the substrate tend to be good. When the number-average molecular weight of the PPE is 21,000 or less, the extrusion moldability during preparation of the PPE composition and during spinning tends to be good. The number-average molecular weight of the PPE is more preferably 9,500 or more or 10,000 or more, and more preferably 17,000 or less or 16,000 or less.

[0051] In one embodiment, the PPE preferably comprises or consists of a combination of a PPE component having a number-average molecular weight of 9,000 to 12,000 and a PPE component having a number-average molecular weight of 14,000 to 17,000. This improves both heat resistance and moldability. In particular, adjusting the blending amount of the PPE component having a number-average molecular weight of 9,000 to 12,000 to 30% by mass to 60% by mass relative to 100% by mass of PPE further improves both heat resistance and moldability, and also increases the affinity between the organic fiber cloth and the matrix resin composition varnish during prepreg production, improving the heat resistance and adhesiveness of the laminate.

[0052] The number average molecular weight of the PPE component having a number average molecular weight of 9,000 to 12,000 may more preferably be 9,500 or more, or 10,000 or more, and may be 11,500 or less, or 11,000 or less, respectively.

[0053] The number average molecular weight of the PPE component having a number average molecular weight of 14,000 to 17,000 may more preferably be 14,500 or more, or 15,000 or more, and may be 16,500 or less, or 16,000 or less, respectively.

[0054] The structural units of the PPE contained in the PPE composition fiber may be the same as those exemplified below for the low-molecular-weight PPE contained in the matrix resin composition. The PPE composition fiber preferably contains at least one of liquid crystal polyester and syndiotactic polystyrene. Both of these polymers can exhibit crystallinity due to the highly ordered structure of the polymer molecules, while also having excellent fluidity, which can improve the heat resistance, mechanical strength, and solvent resistance of the PPE composition fiber and also contribute to the production of PPE composition fiber with good dimensional stability.

[0055] The liquid crystal polyester (hereinafter also referred to as LCP) preferably has a number average molecular weight of 10,000 to 100,000. When the number average molecular weight of the liquid crystal polyester is 10,000 or more, the heat resistance and chemical resistance required for the substrate tend to be good. When the number average molecular weight of the liquid crystal polyester is 100,000 or less, the extrusion moldability during preparation of the PPE composition and during spinning tends to be good. The number average molecular weight of the liquid crystal polyester is more preferably 15,000 to 95,000, or 20,000 to 90,000.

[0056] The syndiotactic polystyrene (hereinafter also referred to as sPS) preferably has a number-average molecular weight of 10,000 to 100,000. When the number-average molecular weight of sPS is 10,000 or more, the heat resistance and chemical resistance required for the substrate tend to be good. When the number-average molecular weight of sPS is 100,000 or less, the extrusion moldability during preparation of the PPE composition and during spinning tends to be good. The number-average molecular weight of sPS is more preferably 15,000 to 95,000, or 20,000 to 90,000.

[0057] In one embodiment, the PPE content in the PPE composition fiber is 5% by mass to 95% by mass, preferably 10% by mass to 90% by mass, or 15% by mass to 85% by mass. When the PPE content is 5% by mass or more, the adhesion between the matrix resin and the PPE composition fiber and the permeability of the matrix resin into the PPE composition fiber are excellent, and the cured prepreg exhibits excellent dielectric constant uniformity. When the PPE content is 95% by mass or less, the melt spinnability is excellent.

[0058] In one aspect, the sPS content in the PPE composition fiber is 5 to 95% by mass, preferably 20 to 80% by mass, 25 to 70% by mass, or 30 to 60% by mass. When the sPS content is 5% or more, the solvent resistance and dielectric constant / dielectric loss tangent of the PPE fiber composition are improved. In particular, when the sPS content is 30% by mass or more, the effect of the sPS crystallinity is more pronounced, resulting in excellent dimensional stability (low warpage). When the sPS content is 95% or less, excellent heat resistance is achieved.

[0059] The LCP content in the PPE composition fiber is 5 to 95% by mass, preferably 5 to 50% by mass, 5 to 40% by mass, or 5 to 30% by mass. When the LCP content is 5% or more, heat resistance and fiber strength are excellent. When the LCP content is 95% or less, spinnability is excellent, and when it is 30% or less, particularly, high-strength spun fibers can be produced.

[0060] When the PPE composition fiber contains both LCP and sPS in a total content of 5 to 95% by mass, the dielectric constant / dielectric loss tangent, heat resistance, and mechanical strength are particularly excellent, preferably 10 to 90% by mass, 20 to 80% by mass, or 30 to 70% by mass.

[0061] In addition, if necessary, a styrene-based elastomer, a flame retardant, an antioxidant, an oil, other additives, etc. may be added. The styrene-based elastomer is preferably at least one selected from the group consisting of a styrene-butadiene block copolymer, a styrene-ethylene-butadiene block copolymer, a styrene-ethylene-butylene block copolymer, a styrene-butadiene-butylene block copolymer, a styrene-isoprene block copolymer, a styrene-ethylene-propylene block copolymer, a styrene-isobutylene block copolymer, a hydrogenated styrene-butadiene block copolymer, a hydrogenated styrene-ethylene-butadiene block copolymer, a hydrogenated styrene-butadiene-butylene block copolymer, a hydrogenated styrene-isoprene block copolymer, and a homopolymer of styrene (polystyrene), and more preferably a hydrogenated styrene-butadiene block copolymer.

[0062] Conventional known flame retardants can be used. Examples include inorganic flame retardants such as antimony trioxide, aluminum hydroxide, magnesium hydroxide, and zinc borate; aromatic bromine compounds such as hexabromobenzene, decabromodiphenylethane, 4,4-dibromobiphenyl, and ethylenebistetrabromophthalimide; and phosphorus-based flame retardants such as resorcinol bis-diphenyl phosphate and resorcinol bis-dixylenyl phosphate. These flame retardants can be used alone or in combination of two or more.

[0063] The PPE composition can be prepared by melt-kneading the above raw materials in a twin-screw extruder or the like at, for example, 300°C or higher. Furthermore, this PPE composition can be heated to, for example, 250°C or higher by a common spinning method, specifically, for example, melt spinning, and then passed through a spinneret and extruded and spun to produce a multifilament fiber. In one embodiment, the diameter of the single yarns constituting the multifilament is 5 μm to 30 μm, preferably 5 μm to 20 μm, or 5 μm to 15 μm. In one embodiment, the number of single yarns constituting the multifilament is 10 to 200, preferably 10 to 100, or 10 to 50. When the single yarn diameter is 5 μm or greater, the tensile strength required for the subsequent weaving and fiber-spreading processes is exhibited, reducing the likelihood of fuzz (single yarn breakage). When the single yarn diameter is 30 μm or less, the thickness of 30 μm to 100 μm generally required for substrate applications can be achieved. When the number of single yarns constituting the multifilament is 10 or more, the dielectric constant of the insulating layer of the substrate can be made uniform by adjusting the subsequent weaving and spreading processes, and when the number of single yarns constituting the multifilament is 200 or less, the above-mentioned fluffing (single yarn breakage) is less likely to occur.

[0064] In one embodiment, the PPE composition fibers are woven to a warp and weft density of 20 to 90 threads / inch and an opening ratio of 1% to 30% or less to produce an organic fiber cloth. When the warp and weft density is 20 threads / inch or more, warping can be prevented and the dielectric constant of the insulating layer of the substrate can be made uniform. When the warp and weft density is 90 threads / inch or less, entanglement of fibers can be prevented and fluff (single yarn breakage) can be suppressed. The warp and weft density is preferably 30 threads / inch to 70 threads / inch or 40 threads / inch to 60 threads / inch.

[0065] When the opening ratio is 1% or more, the matrix resin easily penetrates the organic fiber cloth, improving resin impregnation and heat resistance. Furthermore, the presence of adequate areas without organic fiber cloth improves adhesion between the insulating layer of the substrate and the metal foil (e.g., copper foil). When the opening ratio is 30% or less, the dielectric constant of the insulating layer of the substrate can be made uniform, and the PPE composition fibers are adequately dispersed, improving heat resistance. The opening ratio is preferably 5% to 25%, or 10% to 20%. The warp and weft weave density and opening ratio are values ​​measured by the method described in the Examples section of the present disclosure. The weave structure is not particularly limited, but examples include plain weave, sash weave, satin weave, and twill weave. Among these, plain weave structures are more preferred.

[0066] The fiber surface of the organic fiber cloth may be surface-treated by a silane coupling agent treatment, a corona treatment, a plasma treatment, or the like. In particular, the fiber surface of the organic fiber cloth is preferably treated with an inert gas plasma. Such surface treatments tend to further improve the heat resistance and adhesiveness required for the substrate.

[0067] The dielectric constant of the organic fiber cloth is 2.0 or more and 3.0 or less, preferably 2.5 or more and 2.8 or less. When the dielectric constant of the organic fiber cloth is within this range, the difference in dielectric constant from the dielectric constant of the matrix resin can be reduced. This improves the uniformity of the dielectric constant within the second prepreg and the surface layer, and reduces the difference in delay of electrical signals between wirings on the laminate due to variations in dielectric constant. By using organic fibers containing a polyphenylene ether composition as the organic fiber cloth, the above-mentioned dielectric constant can be achieved, and the delay difference of electrical signals can be reduced.From the viewpoint of achieving both a low dielectric constant and a low dielectric loss tangent and high spinning productivity, the organic fibers preferably contain 5% to 95% by mass of polyphenylene ether and 5% to 95% by mass of either liquid crystal polyester or syndiotactic polystyrene, or both.

[0068] <Matrix resin composition> The first and second matrix resin compositions may be different compositions or the same composition, and are preferably composed of the same composition. Using the same composition can improve the adhesion at the interface between the first resin layer and the second resin layer, prevent delamination due to stress between the first resin layer and the second resin layer that occurs during temperature cycling, and extend the reliability life. Below, we will explain the features common to the first and second matrix resin compositions.

[0069] The matrix resin composition preferably uses a low-molecular-weight PPE having a number-average molecular weight of 1,000 to 5,000. The matrix resin composition preferably contains a low-molecular-weight PPE, a crosslinking agent, and an organic peroxide. In one embodiment, the matrix resin composition may contain (a) a low-molecular-weight PPE, (b) a crosslinking agent, and (c) an organic peroxide, and, optionally, (d) a thermoplastic resin, (e) a flame retardant, and / or (f) a silica filler. The matrix resin composition may be made into a matrix resin composition varnish containing (g) a solvent. Elements that can constitute the matrix resin composition are described below.

[0070] (a) Low molecular weight PPE Low molecular weight PPEs contain phenylene ether units as repeating structural units. The phenylene groups in the phenylene ether units may or may not have substituents. As used herein, the term "polyphenylene ether" includes dimers, trimers, oligomers, and polymers.

[0071] The PPE may also contain other structural units in addition to phenylene ether units. The amount of the other structural units is typically 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, or 5% or less of the total number of structural units. However, the amount of the other structural units may exceed 30% of the total number of structural units as long as the effects of the present disclosure are not impaired.

[0072] Specific examples of PPE include poly(2,6-dimethyl-1,4-phenylene ether), poly(2-methyl-6-ethyl-1,4-phenylene ether), poly(2-methyl-6-phenyl-1,4-phenylene ether), poly(2,6-dichloro-1,4-phenylene ether), copolymers of 2,6-dimethylphenol with other phenols (e.g., 2,3,6-trimethylphenol, 2-methyl-6-butylphenol, etc.), PPE copolymers obtained by coupling 2,6-dimethylphenol with biphenols or bisphenols, and PPEs with linear or branched structures obtained by heating poly(2,6-dimethyl-1,4-phenylene ether) or the like in the presence of a phenolic compound such as a bisphenol or trisphenol and an organic peroxide in a toluene solvent to cause a redistribution reaction. Further examples include PPEs in which the terminal hydroxyl groups of these PPEs have been replaced with functional groups containing carbon-carbon double bonds. Specific examples of the functional group having a carbon-carbon double bond include a vinyl group, an allyl group, an isopropenyl group, a 1-butenyl group, a 1-pentenyl group, a p-vinylphenyl group, a p-isopropenylphenyl group, a m-vinylphenyl group, a m-isopropenylphenyl group, an o-vinylphenyl group, an o-isopropenylphenyl group, a p-vinylbenzyl group, a p-isopropenylbenzyl group, a m-vinylbenzyl group, a m-isopropenylbenzyl group, an o-vinylbenzyl group, an o-isopropenylbenzyl group, a p-vinylphenylethenyl group, a p-vinylphenylpropenyl group, a p-vinylphenylbutenyl group, a m-vinylphenylethenyl group, a m-vinylphenylpropenyl group, a m-vinylphenylbutenyl group, an o-vinylphenylethenyl group, an o-vinylphenylpropenyl group, an o-vinylphenylbutenyl group, a methacryl group, an acryl group, a 2-ethyl acryl group, and a 2-hydroxymethyl acryl group.

[0073] The number-average molecular weight of the low-molecular-weight PPE is preferably 1,000 to 5,000. When the matrix resin composition contains such a low-molecular-weight PPE, an increase in the viscosity of the matrix resin composition varnish can be suppressed, thereby improving the coatability of the matrix resin composition varnish onto cloth. By improving the coatability, various properties required of the matrix resin composition or its cured product can also be improved. The number-average molecular weight of the low-molecular-weight PPE is preferably 1,000 to 3,500, or 1,500 to 3,000.

[0074] The matrix resin composition may contain one type of low-molecular-weight PPE (that is, PPE having a number-average molecular weight of 1,000 to 5,000), or a combination of two or more types of PPE having a number-average molecular weight of 1,000 to 5,000.

[0075] (b) Crosslinking agent Any crosslinking agent capable of initiating or accelerating a crosslinking reaction can be used. The crosslinking agent preferably has a number-average molecular weight of 9,000 or less. When the number-average molecular weight of the crosslinking agent is 9,000 or less, an increase in viscosity of the matrix resin composition varnish can be suppressed, and good resin fluidity can be obtained during heat molding. The number-average molecular weight of the crosslinking agent may more preferably be 100 to 6,000 or 200 to 5,000. The number-average molecular weight of the crosslinking agent is a value measured using GPC in terms of standard polystyrene.

[0076] From the viewpoint of crosslinking reactivity, the crosslinking agent preferably has an average of two or more carbon-carbon unsaturated double bonds per molecule. The crosslinking agent may be composed of one or more compounds. When the crosslinking agent is a polymer or oligomer, the carbon-carbon unsaturated double bond is typically located at the molecular end (i.e., the end of the main chain or branched chain), but this embodiment is not limited thereto. An example of the carbon-carbon unsaturated double bond is the 1,2-vinyl bond in polybutadiene. Specifically, the crosslinking agent is preferably a styrene-butadiene copolymer containing 20% ​​or more by mass of styrene. This crosslinking agent is highly compatible with both the PPE composition fiber and the low-molecular-weight PPE matrix resin, and tends to improve the heat resistance and interlayer adhesion of the substrate. Examples include Cray Valley products Ricon 100, Ricon 181, Ricon 257, and Ricon 184.

[0077] Other examples of crosslinking agents include trialkenyl isocyanurate compounds such as triallyl isocyanurate (TAIC), trialkenyl cyanurate compounds such as triallyl cyanurate (TAC), polyfunctional methacrylate compounds having two or more methacrylic groups in the molecule, polyfunctional acrylate compounds having two or more acrylic groups in the molecule, polyfunctional vinyl compounds having two or more vinyl groups in the molecule such as polybutadiene, vinylbenzyl compounds such as divinylbenzene having vinylbenzyl groups in the molecule, and polyfunctional maleimide compounds having two or more maleimide groups in the molecule such as 4,4'-bismaleimide diphenylmethane. These crosslinking agents may be used alone or in combination. Among these, the crosslinking agent preferably contains at least one compound selected from the group consisting of triallyl cyanurate, triallyl isocyanurate, and polybutadiene. When the crosslinking agent contains at least one of the compounds described above, the crosslinking density becomes higher during the curing reaction (crosslinking reaction), which tends to further improve the heat resistance of the cured product of the matrix resin composition.

[0078] In the matrix resin composition, the mass ratio of low-molecular-weight PPE to crosslinking agent is preferably 25:75 to 95:5, more preferably 32:68 to 85:15, from the viewpoint of balancing the low dielectric constant and low dielectric loss tangent upon curing with the crosslink density of the crosslinked structure.

[0079] (c)Organic peroxide Any organic peroxide capable of promoting the polymerization reaction of a matrix resin composition containing a low-molecular-weight PPE and a crosslinker can be used. Examples of organic peroxides include benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, t-butylcumyl peroxide, di(2-t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumyl peroxide, di-t-butylperoxyisophthalate, t-butylperoxybenzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, and trimethylsilyltriphenylsilyl peroxide. Radical generators such as 2,3-dimethyl-2,3-diphenylbutane can also be used as a reaction initiator for the matrix resin composition. Among these, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, di(2-t-butylperoxyisopropyl)benzene, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexane are preferred from the viewpoint of providing a cured product having excellent heat resistance and mechanical properties, as well as a low dielectric constant and a low dielectric dissipation factor.

[0080] The one-minute half-life temperature of the organic peroxide is preferably 155°C to 185°C, or 160°C to 180°C, or 165°C to 175°C. In this specification, the one-minute half-life temperature is the temperature at which the organic peroxide decomposes and the amount of active oxygen is reduced to half in one minute. The one-minute half-life temperature is determined by a method in which an organic peroxide is dissolved in a solvent inert to radicals, such as benzene, to a concentration of 0.05 mol / L to 0.1 mol / L, and the organic peroxide solution is thermally decomposed under a nitrogen atmosphere.

[0081] When the matrix resin composition is subjected to heat and pressure molding, the one-minute half-life temperature of the organic peroxide is 155°C or higher, and the reaction with the crosslinking agent can be initiated only after the low-molecular-weight PPE has been fully melted, which tends to result in excellent moldability. On the other hand, when the one-minute half-life temperature of the organic peroxide is 185°C or lower, the decomposition rate of the organic peroxide is sufficient under normal heat and pressure molding conditions (e.g., a maximum temperature of 200°C), allowing the crosslinking reaction with the crosslinking agent to proceed efficiently and slowly, making it possible to form a cured product with good electrical properties (particularly dielectric tangent).

[0082] Examples of organic peroxides having a one-minute half-life temperature in the range of 155°C to 185°C include t-hexylperoxyisopropyl monocarbonate (155.0°C) (the one-minute half-life temperature is in parentheses, the same applies below), t-butylperoxy-3,5,5-trimethylhexanoate (166.0°C), t-butylperoxylaurate (159.4°C), t-butylperoxyisopropyl monocarbonate (158.8°C), t-butylperoxy 2-ethylhexyl monocarbonate (161.4°C), t-hexylperoxybenzoate (160.3°C), 2,5-dimethyl-2 ,5-di(benzoylperoxy)hexane (158.2°C), t-butyl peroxyacetate (159.9°C), 2,2-di-(t-butylperoxy)butane (159.9°C), t-butyl peroxybenzoate (166.8°C), n-butyl 4,4-di-(t-butylperoxy)valerate (172.5°C), di(2-t-butylperoxyisopropyl)benzene (175.4°C), dicumyl peroxide (175.2°C), di-t-hexyl peroxide (176.7°C), 2,5-dimethyl-2,5-di(t-butylperoxy)hexane (179.8°C), and t-butylcumyl peroxide (173.3°C).

[0083] The content of the organic peroxide, based on 100% by mass of the total mass of the low-molecular-weight PPE and the crosslinking agent, is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, from the viewpoint of being able to increase the reaction rate, and is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less, from the viewpoint of being able to keep the dielectric constant and dielectric dissipation factor of the obtained cured product low.

[0084] (d) Thermoplastic resin The matrix resin composition preferably contains a thermoplastic resin other than the low-molecular-weight polyphenylene ether and the crosslinking agent. The thermoplastic resin is preferably at least one selected from the group consisting of block copolymers of vinyl aromatic compounds and aliphatic hydrocarbon compounds having carbon-carbon unsaturated double bonds, hydrogenated products thereof (hydrogenated block copolymers obtained by hydrogenating block copolymers of vinyl aromatic compounds and aliphatic hydrocarbon compounds having carbon-carbon unsaturated double bonds), and homopolymers of vinyl aromatic compounds. The content of units derived from vinyl aromatic compounds in the block copolymers or hydrogenated products thereof is preferably 20% by mass or more, and can be 99% by mass or less. Having a content of units derived from vinyl aromatic compounds in the block copolymers or hydrogenated products thereof of 20% by mass or more further improves the compatibility between the low-molecular-weight PPE and the thermoplastic resin, which tends to further improve the adhesion strength between the cured prepreg and the metal foil.

[0085] The vinyl aromatic compound may be any compound having an aromatic ring and a vinyl group in the molecule, such as styrene. The aliphatic hydrocarbon compound having a carbon-carbon unsaturated double bond may be any compound having a linear or branched chain structure in the molecule, such as ethylene, propylene, butylene, isobutylene, butadiene, and isoprene. From the viewpoint of achieving even better compatibility with low-molecular-weight PPE, the thermoplastic resin is preferably at least one selected from the group consisting of styrene-butadiene block copolymers, styrene-ethylene-butadiene block copolymers, styrene-ethylene-butylene block copolymers, styrene-butadiene-butylene block copolymers, styrene-isoprene block copolymers, styrene-ethylene-propylene block copolymers, styrene-isobutylene block copolymers, hydrogenated styrene-butadiene block copolymers, hydrogenated styrene-ethylene-butadiene block copolymers, hydrogenated styrene-butadiene-butylene block copolymers, hydrogenated styrene-isoprene block copolymers, and styrene homopolymers (polystyrene), and more preferably at least one selected from the group consisting of styrene-butadiene block copolymers, hydrogenated styrene-butadiene block copolymers, and polystyrene.

[0086] The hydrogenation rate of the hydrogenated product is not particularly limited, and some carbon-carbon unsaturated double bonds derived from the aliphatic hydrocarbon compound having a carbon-carbon unsaturated double bond may remain.

[0087] The weight-average molecular weight of the thermoplastic resin is preferably 30,000 to 300,000, more preferably 31,000 to 290,000. When the weight-average molecular weight is 30,000 or more, the matrix resin composition tends to have better heat resistance when cured. When the weight-average molecular weight is 300,000 or less, the matrix resin composition tends to have better resin fluidity during thermoforming. The weight-average molecular weight is a value determined by gel permeation chromatography using standard polystyrene conversion.

[0088] The content of the thermoplastic resin is preferably 2 to 20 parts by mass, based on 100 parts by mass of the total of the low-molecular-weight PPE and the crosslinking agent. When the content is 2 parts by mass or more, the matrix resin composition tends to exhibit a low dielectric constant, a low dielectric loss tangent, and good adhesion to the metal foil when cured. When the content is 20 parts by mass or less, the matrix resin composition tends to have even better resin fluidity during heat molding.

[0089] (e) Flame retardants The matrix resin composition preferably contains a flame retardant. From the viewpoint of improving heat resistance, the flame retardant is preferably incompatible with other components contained in the matrix resin composition after curing. Preferably, the flame retardant is incompatible with the low-molecular-weight PPE and / or crosslinking agent in the matrix resin composition after curing. Examples of flame retardants include inorganic flame retardants such as antimony trioxide, aluminum hydroxide, magnesium hydroxide, and zinc borate; aromatic bromine compounds such as hexabromobenzene, decabromodiphenylethane, 4,4-dibromobiphenyl, and ethylenebistetrabromophthalimide; and phosphorus-based flame retardants such as resorcinol bis-diphenylphosphate and resorcinol bis-dixylenylphosphate. These flame retardants may be used alone or in combination of two or more. Among these, decabromodiphenylethane is preferred because it provides a low dielectric constant and a low dielectric loss tangent when the matrix resin composition is cured.

[0090] The content of the flame retardant is not particularly limited, but from the viewpoint of maintaining flame retardancy at the UL Standard 94V-0 level, it is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more per 100 parts by mass of the total of the low-molecular-weight PPE and the crosslinking agent. Furthermore, from the viewpoint of maintaining low dielectric constant and dielectric dissipation factor of the obtained cured product, the content of the flame retardant is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, and even more preferably 40 parts by mass or less.

[0091] (f) Silica filler The matrix resin composition may contain a silica filler. Both natural and synthetic silica can be used as the silica filler, including, for example, fused silica, amorphous silica, aerosil, and hollow silica. The silica filler is preferably a spherical silica filler having an average particle size of 0.1 to 2 μm. An average particle size of 0.1 to 2 μm provides good dispersibility in the matrix resin and excellent dimensional stability (warpage) of the substrate. Furthermore, an average particle size of 2 μm or less provides excellent impregnation of the matrix resin into the PPE resin composition fibers. The content of the silica filler in the matrix resin composition is preferably 10 to 50 mass%, 10 to 45 mass%, or 10 to 40 mass%, in order to easily achieve high dispersibility and provide excellent elastic modulus and dimensional stability (warpage) of the substrate. Furthermore, the silica filler may be surface-treated using a silane coupling agent or the like.

[0092] In addition to the above components, the matrix resin composition may further contain additives such as a heat stabilizer, an antioxidant, a UV absorber, a surfactant, and a lubricant.

[0093] (g) Solvent The matrix resin composition may be prepared as a matrix resin composition varnish containing a solvent in order to obtain suitable fluidity when impregnated into an organic fiber cloth. In the prepreg production process, it is preferable to impregnate the organic fiber cloth with the matrix resin composition varnish and then dry and remove the solvent using a hot air dryer or the like. The solid components in the matrix resin composition may be dissolved or dispersed in the varnish. The amount of solvent may be appropriately adjusted so that the fluidity of the matrix resin composition varnish falls within a suitable range. For example, the amount of solvent in the matrix resin composition varnish may be 20% by mass to 80% by mass, 30% by mass to 70% by mass, or 40% by mass to 60% by mass.

[0094] From the viewpoint of solubility of the components in the matrix resin composition, the solvent is preferably an aromatic compound such as toluene or xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, or chloroform. These solvents may be used alone or in combination of two or more.

[0095] From the viewpoints of favorably dissolving the low-molecular-weight PPE in the solvent and easily ensuring favorable fluidity of the matrix resin composition varnish even at room temperature, aromatic compounds such as toluene are preferred as the solvent, and examples thereof include toluene-methyl ethyl ketone mixed solvents, toluene-cyclohexanone mixed solvents, and toluene-cyclopentanone mixed solvents. Furthermore, toluene alone is also preferred as the solvent, because the matrix resin composition dissolves favorably in such solvents and therefore has excellent impregnation properties into the substrate.

[0096] <Metal-clad laminate> The metal-clad laminate of the present disclosure comprises a laminate of the present disclosure and a metal foil laminated on the surface layer thereof. By virtue of the laminate of the present disclosure, the metal-clad laminate of the present disclosure has an excellent dielectric constant, dielectric loss tangent, and dielectric constant uniformity, as well as a low thermal expansion coefficient and high heat resistance. The metal foil can be laminated on the surface of the first resin layer constituting the surface layer and / or between the first resin layers. It may be laminated between the first resin layer constituting the surface layer and the second resin layer constituting the core layer, or it may be laminated between the second resin layers constituting the core layer. In the metal-clad laminate, the first resin layer and the second resin layer form an insulating layer, which may be formed from a single first resin layer or second resin layer, or from two or more first resin layers and / or second resin layers.

[0097] Fig. 5 is a schematic diagram showing a cross section of a metal-clad laminate of the present disclosure. In Fig. 5, the metal-clad laminate (200) has a core layer (10) consisting of five first resin layers (1), and surface layers (20) consisting of two second resin layers laminated on both sides of the core layer (10). The metal-clad laminate (200) has copper foil (3) laminated on its surface, and also has copper foil (3) laminated between the first resin layer constituting the surface layer and the second resin layer constituting the core layer, and between the second resin layers constituting the core layer.

[0098] The metal foil may be copper or aluminum. The metal foil used here is not particularly limited as long as it is used as a printed wiring board material, but known copper foils such as rolled copper foil and electrolytic copper foil are preferred. The thickness of the metal foil (conductor layer) is not particularly limited, but is preferably 1 μm to 70 μm, more preferably 1.5 μm to 35 μm.

[0099] The molding method and molding conditions for the metal-clad laminate are not particularly limited, and general techniques and conditions for laminates and multilayer boards for printed wiring boards can be applied. For example, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, an autoclave molding machine, etc. can be used to mold the metal-clad laminate. In addition, the temperature for molding the metal-clad laminate is 100°C to 300°C, and the pressure is 2 kgf / cm. 2 ~100kgf / cm 2 The heating time is generally in the range of 0.05 to 5 hours. If necessary, post-curing can be performed at a temperature of 150 to 300°C. It is also possible to form a multilayer board by combining the above-mentioned prepreg with a separately prepared wiring board for an inner layer and laminating it.

[0100] The surface layer may be laminated by a build-up method. Here, "build-up" refers to the production of a multilayer printed wiring board by laminating prepregs and / or metal-clad laminates and repeatedly performing processes such as drilling and wiring on each layer. By laminating surface layers with a highly uniform dielectric constant using a build-up method and then performing fine wiring processing, it is possible to reduce the difference in delay between electrical signals among the fine wiring, and electronic components can be mounted at a high density.

[0101] More specifically, prepregs and / or metal-clad laminates can be used as build-up materials for printed wiring boards. In printed wiring boards formed using prepregs, the cured layers of the prepregs constitute the insulating layers. Similarly, in printed wiring boards formed using metal-clad laminates, the cured layers of the prepregs constitute the insulating layers.

[0102] When the prepreg is used as a build-up material, a metal-clad laminate can be produced using the prepreg, and then a printed wiring board can be obtained by a build-up method. Alternatively, when the prepreg is used as a material for a multilayer printed wiring board as described below, the prepreg may be used as it is as a build-up material.

[0103] When the prepreg is used as a build-up material, the prepreg is surface-treated in a conventional manner, and a wiring pattern (conductor layer) is formed on the surface of the insulating layer by plating, thereby obtaining a printed wiring board.

[0104] When a metal-clad laminate is used as a build-up material, a printed wiring board can be obtained by etching the metal foil of the metal-clad laminate in the usual manner, then surface-treating the layer made of prepreg (insulating layer), and forming a wiring pattern (conductor layer) on the surface of the insulating layer by plating.

[0105] In either case, various other processes (for example, hole processing to form via holes, through holes, etc.) may be added for each lamination as needed.

[0106] <Printed wiring board> A printed wiring board is a metal-clad laminate from which a portion of the metal foil has been removed. A printed wiring board can typically be formed by a method of pressurizing and heat-molding using the above-described prepreg. Examples of cloth include the same organic fiber cloths as those described above for the prepreg. By incorporating the laminate of the present disclosure, the printed wiring board has excellent dielectric constant, dielectric loss tangent, and dielectric constant uniformity, as well as a low thermal expansion coefficient and high heat resistance. [Example]

[0107] Examples of the present disclosure will be described in detail below, but the present disclosure is not limited to these examples.

[0108] <Measurement and evaluation methods> (1) Number average molecular weight The number-average molecular weights of PPE and thermoplastic resins were determined by gel permeation chromatography (GPC) by comparing the elution times of standard polystyrenes with known molecular weights. Specifically, a measurement sample was prepared at a concentration of 0.2 w / vol% (solvent: chloroform), and the measurement was performed using a Tosoh HLC-8220GPC (Showa Denko) column (Shodex GPC KF-405L HQ x 3, eluent: chloroform), injection volume: 20 μL, flow rate: 0.3 mL / min, column temperature: 40 °C, and detector: RI.

[0109] (2) Single yarn diameter The cross sections of 100 randomly selected filaments were photographed using a scanning electron microscope (Hitachi Science Systems, SEMEDX3 Type N), the diameters were measured, and the average value was calculated.

[0110] (3) Weave density of the cross section Measurements were taken in both the warp and weft directions in accordance with JIS R3420.

[0111] (4) Cloth aperture ratio A 100 mm square (approximately 4 inch wide) was cut from the center of the cloth roll, and the total warp width (i.e., the total width of the warp threads in the entire 100 mm × 100 mm cloth) and total weft width (i.e., the total width of the weft threads in the entire 100 mm × 100 mm cloth) were measured in an optical microscope image of the cloth surface, and the average values ​​for each of the warp and weft threads were calculated. Based on this average value and the weave density of the warp and weft threads calculated above, the opening ratio was calculated according to the following formula. Opening rate = (25.4 mm ÷ warp density - warp width mm) x (25.4 mm ÷ weft density - weft width mm) ÷ ((25.4 mm ÷ warp density) x (25.4 mm ÷ weft density))

[0112] (5) Thickness of the cloth Measurements were made in accordance with JIS R3420.

[0113] (6) Heat resistance The prepregs were laminated in the structure shown in Table 1, and heated from room temperature at a rate of 3°C / min while applying a pressure of 5 kg / cm. 2 After the temperature reached 130°C, the material was heated at a rate of 3°C / min while applying a pressure of 40 kg / cm. 2 After the temperature reached 200°C, the pressure was increased to 40 kg / cm while maintaining the temperature at 200°C. 2 The laminate was then vacuum-pressed for 60 minutes at 121°C. The laminate was then cut into 50mm x 50mm pieces, and five pieces were placed in a pressure cooker at 121°C saturated vapor pressure for 10 hours. After removal, the surface moisture was wiped off, and the laminate was immersed in a solder bath at 288°C for 20 seconds, and the swelling of the laminate was evaluated. ◎: No swelling at all 〇: One bulge occurs △: Two or more blisters ×: Three or more blisters

[0114] (7) Dielectric constant and dielectric loss tangent of the surface layer (electrical properties, 10 GHz) As in the heat resistance evaluation (6) above, laminates were prepared by stacking eight prepregs shown in Table 1 for the surface layer (b) in Examples 1 to 8 and Comparative Examples 1 and 2, and eight prepregs shown in Table 1 for the core layer (a) in Comparative Example 3, and the dielectric constant and dielectric loss tangent at 10 GHz were measured by the cavity resonance method. Measurements were performed using a network analyzer (N5230A, manufactured by Agilent Technologies) and a cavity resonator (Cavity Resornator CP series) manufactured by Kanto Electronics Application Development Co., Ltd.

[0115] (8) Dielectric constant uniformity of the surface layer (local variation in dielectric constant) Laminates were prepared in the same manner as in (6) Heat Resistance Evaluation and (7) Surface Layer Dielectric Constant and Dielectric Loss Tangent Evaluation, except that a single prepreg was used. The laminates were embedded in resin, and the cross sections were machined and polished. Cross-sectional images were taken with a scanning electron microscope (Hitachi Science Systems, Ltd., SEMEDX3 Type N) over a continuous measurement width of 25 mm. The resulting cross-sectional images were analyzed to measure the fiber loading (as the total area of ​​the fiber portion within the field of view) and matrix resin composition loading (as the total area of ​​the resin portion within the field of view) for each unit width of 50 μm, and the ratio of fiber loading / matrix resin composition loading was calculated. The dielectric constant per unit width was then calculated using the ratio of fiber loading / matrix resin composition loading calculated for each unit width, the dielectric constant of the fiber, and the dielectric constant of the matrix resin composition. The standard deviation of the dielectric constant across the unit width was used as the local dielectric constant variation.

[0116] (9) Amount of board warpage As in the heat resistance evaluation (6) above, a laminate was prepared by laminating a core layer (a) and a surface layer (b) in the structure shown in Table 1, and four 50 mm square samples were randomly cut out. The amount of warpage at each of the four corners of each sample (the larger of the front and back) was measured with a vernier caliper. The average value of the four corners was calculated and used as the amount of warpage of the substrate.

[0117] (10) Thermal expansion coefficient The thermal expansion coefficient was measured using the TMA method (thermo-mechanical analysis). Similar to the heat resistance evaluation in (6) above, a core layer (a) and a surface layer (b) were laminated to the structure shown in Table 1 to obtain the desired structure, and the resulting laminate was cut into 5 mm squares, the thickness was measured, and the cross-sectional area of ​​the specimen was calculated. A test piece was loaded with 40 g weight / cm. 2 The specimen is heated at a temperature rising rate of 10°C / min under a load of 0.01g, and the change in length of the specimen is measured. The specimen is heated from 25°C to 300°C, and the change in length over the temperature range of 50°C to 100°C is divided by the length of the specimen, and then divided by 50 to obtain the coefficient of thermal expansion. Alternatively, a laminate with a desired layer structure may be prepared by polishing some of the layers of the laminate.

[0118] <Examples 1 to 8 and Comparative Examples 1 to 3> Preparation of PPE composition for organic fiber cloth: PPE, sPS, LCP, and SEBS (styrene-ethylene-butadiene-styrene copolymer) having the number average molecular weights (Mn) shown in Table 1 were melt-kneaded at 350°C in a twin-screw extruder in the blending ratios (by mass) shown in Table 1 to obtain PPE compositions.

[0119] Preparation of organic fiber cloth: The PPE composition was extruded through a spinneret in a melt spinning machine and spun to produce a multifilament. The diameter of the single yarn was 20 μm, and the multifilament consisted of 50 single yarns.

[0120] Next, the multifilament was woven, physically processed, desizing, surface treated, and opened to produce an organic fiber cloth with a warp and weft density of 30 threads / inch, a thickness of 50 μm, and an opening ratio of 20%.

[0121] Glass cloth: The glass cloth used was low dielectric glass cloth L2116 (weave density 60×58 / inch, thickness 95 μm, opening ratio 5%).

[0122] Preparation of matrix resin composition: [material] The following materials were used: (low molecular weight PPE) Methacrylic-terminated PPE (product name: SA9000, manufactured by Sabic Innovative Plastics, Mn: 2756, number of terminal functional groups per molecule: 2) (Crosslinking agent) ·RICON100 (manufactured by CRAY VALLEY, weight average molecular weight: 4500) TAIC (Mitsubishi Chemical Corporation, molecular weight: 249.7) (organic peroxide) Bis(1-tert-butylperoxy-1-methylethyl)benzene (product name "Perbutyl P", manufactured by NOF Corporation) (thermoplastic resin) Hydrogenated styrene-based thermoplastic resin (SEBS) (product name: Tuftec H1051, manufactured by Asahi Kasei Corporation, weight-average molecular weight (Mw): 49,000, styrene unit content: 30% by mass) (Flame retardant) Decabromodiphenylethane (product name "SAYTEX8010", manufactured by Albemarle) (Other ingredients) Epoxy resin Epoxy resin: Cresol novolac epoxy resin (product name "N680-75M", manufactured by Dainippon Ink and Chemicals) Hardener Dicyandiamide (DICY)

[0123] Preparation of matrix resin composition varnish: Each material was weighed in advance, and a 50:50 toluene / methyl ethyl ketone mixed solvent was placed in a container. While stirring with a mixer, each material was added and mixed for 5 hours or more to prepare a 50% by mass matrix resin composition varnish.

[0124] Preparation of first prepreg and second prepreg: The cloth was impregnated with the resin composition varnish at a constant tension of about 100 N / m, scraped off with a slit, and dried at 120°C for 3 minutes to prepare a prepreg.

[0125] Preparation of laminates: Prepregs were made by fabricating eight core layers and eight surface layers using the materials described above and organic fibers with the compositions shown in Table 1, and then impregnating the cloth with varnish. The compositions and evaluation results are shown in Table 1.

[0126] [Table 1]

[0127] <Examples 9 to 15 and Comparative Examples 4 to 6> The following computer simulation was used to simulate the performance of laminates when the number of core and surface layers, the coefficient of thermal expansion (CTE) before curing, and the coefficient of thermal expansion (CTE) after curing were varied.

[0128] Computer simulation software: The simulation software used was Abaqus2018, a finite element analysis software. 1. Layer composition The layer structure of the model is the same as the cross-sectional structure of the multilayer structure shown in Figure 6. That is, it is a laminated structure in which surface layers (20) are laminated on both sides of a core layer (10). The "number of layers" refers to the total number of layers. For example, if the number of core layers is 8 and the number of surface layers is 8, this means that surface layers made of four second resin layers are arranged on both sides of a core layer made of eight first resin layers. 2. Model The structure shown in Figure 6 was modeled. A two-dimensional mesh was created with the laminate length set to 4 mm and thickness set to 1.6 mm, the copper foil (3) on the laminate and on the substrate located on the laminate set to 0.68 mm and thickness set to 0.025 mm, and the substrate (4) located on the laminate set to 4 mm and thickness set to 1 mm. The solder formed a circle with a diameter of 0.68 mm, and the center line of the circle was cut symmetrically at positions 0.205 mm above and below and 0.41 mm high to create the model and mesh. 3. Thermal expansion coefficient The thermal expansion coefficient of the laminate was set as shown in Table 2. Other thermal expansion coefficients were set as follows: copper foil: 17 ppm / °C, substrate located on the laminate: 12 ppm / °C, and solder: 23 ppm / °C. 4. Temperature Cycling The temperature load was set to apply three cycles of uniform temperature rise and fall to the entire model. The temperature was set to -55°C to 125°C and held for 5 minutes. The temperature rise and fall times were set to 10 minutes, excluding the start and end.

[0129] Simulation results: Thermal stress analysis was performed on each member of each example and comparative example, and the inelastic strain in the solder joint was calculated. Furthermore, the number of cycles until failure was simulated based on the fatigue life diagram described in Non-Patent Document 1, and the results were evaluated according to the following criteria. The results are shown in "Temperature Cycle Test" in Table 2. ○ The number of repeated breakages is 1E+5 or more △ Number of repeated breakages: 5E+4 times or more to less than 1E+5 times × The number of repeated breakages is less than 5E+4

[0130] The "thermal expansion coefficient as laminate" in Table 2 was calculated as follows. In the third temperature cycle, the change in length of the model in the temperature range of 50°C to 100°C was divided by the length of the model, and then divided by 50 to obtain the thermal expansion coefficient.

[0131] The "electrical signal delay in the surface layer" in Table 2 was simulated and evaluated as follows. Computer simulation software: The simulation software used was Ansys HFSS, a finite element analysis software. 1. Layer composition The layer structure of the model is the same as the cross-sectional structure of the multilayer structure shown in Figure 7. That is, it is a laminated structure in which surface layers (20) are laminated on both sides of a core layer (10). The "number of layers" refers to the total number of layers. For example, if the number of core layers is 8 and the number of surface layers is 8, this means that surface layers each consisting of four second resin layers are disposed on both sides of a core layer consisting of eight first resin layers. 2. Model The structure shown in Figure 7 was modeled. The laminate was 3.68 mm long, 7.36 mm deep, and 1.6 mm thick, with copper foil (3) placed between the second and third layers from the surface of the laminate. Two copper foils (3) measuring 0.27 mm long, 7.36 mm deep, and 0.018 mm thick were placed on the laminate. The copper foils were placed at positions where the warp and weft threads of the cloth overlap, resulting in a high cloth filling rate, and at positions where the resin filling rate between the weaves of the cloth is high, and a 3D model and mesh were created. 3. Dielectric constant The dielectric constants of the matrix resin, glass cloth, and organic fiber cloth in the laminate were set as shown in Table 2. 4. Calculation method for electrical signal delay difference A 10 GHz high-frequency signal was applied to the two copper foil wiring of the model, and the delay time of the signal was measured. The difference in electrical signal delay between the wirings was calculated.

[0132] Simulation results: Simulations were performed on each member of each example and comparative example, and the electrical signal delay difference was calculated and evaluated according to the following evaluation criteria. The results are shown in Table 2 under "Electrical signal delay in surface layer." ○ Signal delay time is less than 0.25 psec / inch × Signal delay time is 0.25psec / inch or more

[0133] [Table 2] [Explanation of symbols]

[0134] 1 First resin layer 2 Second resin layer 3 Copper foil 4 substrate 10 コアlayer 20 Surface layer 100 laminated board 200 Metal Tensor Laminated Plate

Claims

1. a core layer including at least one first resin layer in which a glass fiber cloth is impregnated or coated with a first matrix resin; a surface layer laminated on one or both sides of the core layer and including at least one second resin layer in which a second matrix resin is impregnated or coated on an organic fiber cloth; A laminate comprising: A laminate, wherein the second resin layer has a thermal expansion coefficient in a planar direction greater than the thermal expansion coefficient in a planar direction of the first resin layer.

2. The thermal expansion coefficient of the first resin layer in the planar direction is 3 ppm / °C or more and less than 20 ppm / °C, and the thermal expansion coefficient of the second resin layer in the planar direction is 18 ppm / °C or more and 200 ppm / °C or less. The laminate according to claim 1.

3. The laminate according to claim 1 or 2, wherein the surface layers are laminated on both sides of the core layer.

4. The laminate according to any one of claims 1 to 3, wherein the fibers of the organic fiber cloth are fibers made of a resin composition containing polyphenylene ether.

5. The resin composition containing polyphenylene ether contains 5% by mass to 95% by mass of polyphenylene ether and 5% by mass to 95% by mass of at least one selected from liquid crystal polyester and syndiotactic polystyrene, based on the total mass of the resin composition. The laminate according to claim 4.

6. The thermal expansion coefficient in the planar direction of the first resin layer is 3 ppm / ° C. or more and less than 20 ppm / ° C., and the thermal expansion coefficient in the planar direction of the second resin layer is 20 ppm / ° C. or more and 150 ppm / ° C. or less. The laminate according to any one of claims 1 to 5.

7. The laminate according to any one of claims 1 to 6, wherein the core layer comprises two or more continuous first resin layers.

8. The laminate according to any one of claims 1 to 7, wherein the number of layers of the first resin layer included in the core layer is greater than the number of layers of the second resin layer included in the surface layer.

9. The dielectric constant of the second matrix resin contained in the surface layer is 2.0 or more and 3.0 or less, and the dielectric constant of the organic fiber cloth is 2.0 or more and 3.0 or less. A laminate according to any one of claims 1 to 8.

10. A metal-clad laminate comprising the laminate according to any one of claims 1 to 9 and a metal foil laminated on the surface layer of the laminate.

11. a step of laminating at least one first prepreg obtained by impregnating or coating a glass fiber cloth with a first matrix resin and at least one second prepreg obtained by impregnating or coating an organic fiber cloth with a second matrix resin to prepare a prepreg laminate comprising a core layer including the at least one first prepreg and surface layers including the at least one second prepreg laminated on one or both sides of the core layer; curing the first matrix resin and the second matrix resin; A method for manufacturing a laminate, comprising: A method for manufacturing a laminate, wherein the second prepreg has a larger thermal expansion coefficient in a planar direction than the first prepreg.

12. The method according to claim 11, wherein the thermal expansion coefficient of the first prepreg in the planar direction is 3 ppm / °C or more and less than 20 ppm / °C, and the thermal expansion coefficient of the second prepreg in the planar direction is 18 ppm / °C or more and 200 ppm / °C or less.

13. 13. The method of claim 11 or 12, wherein the surface layers are laminated to both sides of the core layer.

14. The method according to any one of claims 11 to 13, wherein the fibers of the organic fiber cloth are fibers made of a resin composition containing polyphenylene ether.

15. The method according to claim 14, wherein the resin composition containing polyphenylene ether comprises, based on the total mass of the resin composition, 5% by mass to 95% by mass of polyphenylene ether and 5% by mass to 95% by mass of at least one selected from liquid crystal polyester and syndiotactic polystyrene.

16. The thermal expansion coefficient in the planar direction of the first prepreg is 3 ppm / °C or more and less than 20 ppm / °C, and the thermal expansion coefficient in the planar direction of the second prepreg is 20 ppm / °C or more and 150 ppm / °C or less. The method according to any one of claims 11 to 15.

17. The method according to any one of claims 11 to 16, wherein two or more layers of the first prepreg are laminated continuously on the core layer.

18. The method according to any one of claims 11 to 17, wherein the number of layers of the first prepreg laminated on the core layer is greater than the number of layers of the second prepreg laminated on the surface layer.

19. The method according to any one of claims 11 to 18, wherein the dielectric constant of the second matrix resin contained in the surface layer is 2.0 or more and 3.0 or less, and the dielectric constant of the organic fiber cloth is 2.0 or more and 3.0 or less.

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