Wiring board manufacturing method

Abstract

To provide a method for manufacturing a wiring board that can suppress an occurrence of resin chipping due to cutting of a resin sheet, suppress changes in the thickness of an insulating layer even when the board undergoes processes including vacuum hot pressing, and achieve good metal foil adhesion and glass transition temperature.SOLUTION: There is provided a method for manufacturing a wiring board, including: (1) heating and laminating a resin sheet having a support and a resin composition layer provided on the support onto a substrate so that the resin composition layer of the resin sheet is bonded to the substrate; (2) peeling the support from the resin composition layer; and (3) heating and pressing a metal foil onto the resin composition layer using a vacuum hot press, in which in the above (3), a minimum melt viscosity of the resin composition layer before heat and pressure bonding is 2,000 poise to 20,000 poise when measured in a temperature range from 60°C to 200°C.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a wiring board using a resin sheet. [Background technology]

[0002] A known manufacturing technique for printed wiring boards is a build-up method in which insulating layers and conductor layers (circuit layers) are alternately stacked. In build-up manufacturing methods, the insulating layer is generally formed by laminating a resin composition layer on an inner layer substrate using an adhesive sheet or the like containing a resin composition layer and curing the resin composition layer. After the insulating layer is formed, a circuit is formed on the insulating layer.

[0003] When an adhesive sheet having a resin composition layer formed on a metal foil is used, it is possible to form a circuit using the metal foil by a subtractive method or a modified semi-additive method. For example, Patent Document 1 discloses an adhesive sheet including copper foil and a resin composition layer made of a specific resin composition formed on the copper foil.

[0004] When using the subtractive method or modified semi-additive method, wiring boards can be manufactured easily, but conventionally, a resin sheet with a metal foil must be used, and the method must be compatible with processes including vacuum hot pressing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-359444 Summary of the Invention [Problem to be solved by the invention]

[0006] For example, one possible method involves winding a metal foil-equipped resin sheet into a roll, adhering the resulting rolled resin sheet to a circuit board, cutting it, and subjecting the cut resin sheet to a vacuum hot press. However, it has been found that when a metal foil-equipped resin sheet is temporarily attached to a circuit board using a temporary attachment device and then cutting the temporarily attached resin sheet, resin chipping tends to occur at the cut surface due to differences in hardness between the metal foil and the resin sheet. Furthermore, if the minimum melt viscosity of the resin composition layer is set low to prevent the above-mentioned resin chipping problem, the thickness of the resin composition layer (insulating layer) tends to decrease after thermocompression bonding by vacuum hot pressing. Large thickness variations reduce the uniformity of the insulating layer thickness, so suppressing the thickness reduction becomes an issue. Furthermore, a low minimum melt viscosity also poses the problem of a lower glass transition temperature of the insulating layer. On the other hand, if the minimum melt viscosity is too high, in addition to the above-mentioned resin chipping problem, problems such as reduced adhesion of the metal foil to the resin composition layer arise.

[0007] An object of the present invention is to provide a method for manufacturing a wiring board in which a circuit is formed by using a metal foil according to a subtractive method or a modified semi-additive method, which can suppress the above-mentioned resin chipping, changes in the thickness of the resin composition layer (insulating layer) after vacuum hot pressing, a decrease in metal foil adhesion, and a decrease in glass transition temperature. [Means for solving the problem]

[0008] As a result of extensive research, the inventors have found that the problem of resin chipping that occurs when the resin sheet is cut can be solved by laminating a resin sheet having a support and a resin composition layer onto a substrate, peeling off the support, and thermocompressing a metal foil to the resin composition layer. They have also found that by setting the minimum melt viscosity of the resin composition layer before thermocompression to 2,000 poise to 20,000 poise, changes in the thickness of the insulating layer can be suppressed and good metal foil adhesion and glass transition temperature can be achieved, leading to the completion of the present invention.

[0009] That is, the present invention includes the following. [1] (1) A step of heating and laminating a resin sheet having a support and a resin composition layer provided on the support to a substrate so that the resin composition layer of the resin sheet is bonded to the substrate; (2) peeling the support from the resin composition layer; and (3) A step of heating and pressing the metal foil onto the resin composition layer using a vacuum hot press. A method for manufacturing a wiring board, comprising: A method for producing a wiring board, wherein in the step (3), the minimum melt viscosity of the resin composition layer before thermocompression bonding is 2,000 to 20,000 poise when measured in a temperature range from 60°C to 200°C. [2] The method for producing a wiring board according to [1] above, further comprising the step of drying the resin composition layer (A) as a step carried out after the step (1) above and before the step (2), or as a step carried out after the step (2) above and before the step (3). [3] The method for producing a wiring board according to [1] above, wherein the minimum melt viscosity of the resin composition layer before lamination in step (1) is lower than the minimum melt viscosity of the resin composition before heat-pressing in step (3). [4] The method for producing a wiring board according to [1] above, wherein the heating temperature during lamination in step (1) is 80 to 140°C. [5] The method for producing a wiring board according to [1] above, wherein the heating temperature during thermocompression bonding in step (3) is 170 to 230°C. [6] The method for producing a wiring board according to the above [1], wherein the pressure applied during the thermocompression bonding in the step (3) is 0.5 to 2.0 MPa. [7] The method for producing a wiring board according to the above [1], wherein the thickness of the resin composition layer before lamination in the step (1) is 40 μm or less. [8] The method for producing a wiring board according to the above [1], wherein the glass transition temperature of the resin composition layer after the heat-pressure bonding in the step (3) is 140°C or higher. [9] The method for producing a wiring board according to the above [1], wherein the thickness of the resin composition layer after the thermocompression bonding in the step (3) is more than 10 μm.

[10] The method for producing a wiring board according to [1] above, wherein the thickness reduction rate of the resin composition layer after the heat-pressing bonding in step (3) relative to the resin composition layer before lamination in step (1) is 40% or less.

[11] The method for producing a wiring board according to [1] above, wherein the content of the organic solvent in the resin composition layer before the thermocompression bonding in the step (3) is 0.3 to 2.5 mass % when all components in the resin composition layer are 100 mass %.

[12] The method for producing a wiring board according to the above [1], wherein the support is a plastic film.

[13] (4) A process for forming a circuit pattern from metal foil using a subtractive method. The method for manufacturing the wiring board according to [1] above, comprising:

[14] (4') A process for forming a circuit pattern from metal foil using a modified semi-additive process The method for manufacturing the wiring board according to [1] above, comprising:

[15] The method for producing a wiring board according to the above [1], wherein the resin composition layer contains a thermosetting resin.

[16] The method for producing a wiring board according to

[15] above, wherein the thermosetting resin comprises a thermosetting resin selected from the group consisting of epoxy resin, cyanate ester resin, maleimide resin, and thermosetting modified polyphenylene ether resin.

[17] The method for producing a wiring board according to the above [1], wherein the resin composition layer contains an inorganic filler.

[18] The method for producing a wiring board according to

[17] above, wherein the content of the inorganic filler in the resin composition layer is 40 to 75 mass % when the non-volatile components in the resin composition layer are 100 mass %.

[19] The method for producing a wiring board according to the above [1], wherein the resin composition layer contains a thermoplastic resin.

[20] The method for producing a wiring board according to

[19] above, wherein the thermoplastic resin comprises a thermoplastic resin selected from thermoplastic polyimide resin, polycarbonate resin, phenoxy resin, polyvinyl acetal resin, and copolymers.

[21] The method for producing a wiring board according to

[20] above, wherein the copolymer is a copolymer obtained by polymerizing two or more monomers selected from styrene, ethylene, propylene, isoprene, butadiene, acrylate, and methacrylate, or a hydrogenated product thereof.

[22] The method for producing a wiring board according to

[19] above, wherein the weight-average molecular weight of the thermoplastic resin is 5,000 to 100,000. [Effects of the Invention]

[0010] According to the method for manufacturing a wiring board of the present invention, it is possible to suppress the occurrence of resin chipping that occurs when cutting a resin sheet, and even when the resin sheet undergoes a process including vacuum hot pressing, it is possible to suppress changes in the thickness of the insulating layer and achieve good metal foil adhesion and glass transition temperature. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below with reference to preferred embodiments thereof. However, the present invention is not limited to the following embodiments and examples, and can be implemented with any modifications within the scope of the claims of the present invention and their equivalents.

[0012] <Method of manufacturing a wiring board> The present invention provides a method for manufacturing a wiring board, comprising the steps of: (1) heating and laminating a resin sheet having a support and a resin composition layer provided on the support to a substrate so that the resin composition layer of the resin sheet is bonded to the substrate; (2) peeling the support from the resin composition layer; and (3) heating and pressing a metal foil to the resin composition layer using a vacuum hot press, wherein in step (3), the minimum melt viscosity of the resin composition layer before heat and pressure bonding is 2,000 to 20,000 poise when measured in a temperature range from 60°C to 200°C.

[0013] Step (1) is a step of heating and laminating a resin sheet having a support and a resin composition layer provided on the support to a substrate so that the resin composition layer of the resin sheet is bonded to the substrate.

[0014] The support in the resin sheet can be, for example, a plastic film.

[0015] Examples of materials for plastic films include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, with inexpensive polyethylene terephthalate being particularly preferred.

[0016] The surface of the support to be bonded to the resin composition layer may be subjected to a matte treatment, a corona treatment, or an antistatic treatment. Alternatively, a support having a release layer on the surface to be bonded to the resin composition layer may be used as the support. Examples of the release agent used in the release layer of the support having a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. Commercially available products may be used as the support having a release layer, such as "SK-1," "AL-5," and "AL-7" manufactured by Lintec Corporation, "Lumirror T60" manufactured by Toray Industries, Inc., "Purex" manufactured by Teijin Limited, and "Uni-Peel" manufactured by Unitika Limited, which are PET films having a release layer primarily composed of an alkyd resin-based release agent.

[0017] The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, more preferably 10 μm to 60 μm. When a support with a release layer is used, it is preferable that the thickness of the entire support with a release layer is in the above range.

[0018] The thickness of the resin composition layer before lamination in step (1) is, for example, 100 μm or less, and from the viewpoint of thinning the printed wiring board, it is preferably 70 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less, and particularly preferably 40 μm or less, and from the viewpoint of ensuring sufficient insulation, it is preferably 5 μm or more, preferably 10 μm or more, preferably 13 μm or more, and preferably 15 μm or more.

[0019] In step (1), the minimum melt viscosity of the resin composition layer before lamination is preferably 300 poise or more, more preferably 500 poise or more, even more preferably 700 poise or more, and particularly preferably 1000 poise or more, from the viewpoint of achieving an appropriate film thickness during lamination. In terms of sufficiently embedding the inner layer circuits, it is preferably 10,000 poise or less, even more preferably 8,000 poise or less, and even more preferably 7,000 poise or less. In particular, the minimum melt viscosity of the resin composition layer before lamination in step (1) is even more preferably less than 2,000 poise, and particularly preferably 300 poise or more but less than 2,000 poise, from the viewpoint of achieving both the embeddability of the inner layer circuits during lamination in step (1) and an appropriate minimum melt viscosity in step (3) described below. Here, the minimum melt viscosity refers to the minimum melt viscosity measured when the dynamic viscoelastic modulus is measured in a temperature range from 60°C to 200°C.

[0020] The content of organic solvent in the resin composition layer of the resin sheet before lamination used in step (1) is, when all components in the resin composition layer are taken as 100% by mass, for example, 0% by mass or more, 0.1% by mass or more, or 0.3% by mass or more; from the viewpoint of embeddability of inner layer circuits, it is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, even more preferably 1.2% by mass or more, and particularly preferably 1.5% by mass or more; and from the viewpoint of suppressing the generation of voids due to the tackiness of the resin sheet, it is preferably 3.0% by mass or less, more preferably 2.8% by mass or less, and even more preferably 2.5% by mass or less.

[0021] The substrate used in step (1) is a member that will become the substrate of the wiring board, and examples thereof include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The substrate may have a conductor layer on one or both sides, and this conductor layer may be patterned. A substrate having a conductor layer (circuit) formed on one or both sides is sometimes called an "inner layer circuit board." The substrate also includes intermediate products on which an insulating layer and / or a conductor layer is to be formed during the production of a wiring board. The wiring board may also be a component-embedded circuit board with a built-in component.

[0022] The lamination in step (1) can be performed, for example, by thermocompression bonding the resin sheet to the substrate from the support side of the resin sheet. Examples of a member for thermocompression bonding the resin sheet to the substrate (hereinafter also referred to as a "thermocompression bonding member") include a heated metal plate (such as a SUS panel) or a metal roll (such as a SUS roll). It is preferable to press the thermocompression bonding member not directly onto the resin sheet, but via an elastic material such as heat-resistant rubber so that the resin sheet can sufficiently conform to the surface irregularities of the substrate.

[0023] The lamination in step (1) may be performed by a vacuum lamination method. Lamination by the vacuum lamination method can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nikko Materials Co., Ltd., and a batch-type vacuum pressure laminator. The lamination in step (1) may also be performed using a press device. A commercially available press device can be used.

[0024] The heating temperature during lamination in step (1) is preferably 60°C or higher, more preferably 70°C or higher, even more preferably 80°C or higher, and particularly preferably 90°C or higher, from the viewpoint of obtaining sufficient resin flowability; and is preferably 160°C or lower, more preferably 150°C or lower, even more preferably 140°C or lower, and particularly preferably 130°C or lower, from the viewpoint of suppressing resin viscosity increase during lamination. The pressure conditions during lamination in step (1) are preferably 0.2 MPa or higher, more preferably 0.3 MPa or higher, from the viewpoint of obtaining sufficient resin flowability; and are preferably 30 MPa or lower, more preferably 25 MPa or lower, from the viewpoint of obtaining film thickness uniformity during lamination. The heating and pressing time during lamination while maintaining the heating temperature and pressure conditions within the above ranges is preferably 10 seconds or higher, more preferably 20 seconds or higher, and particularly preferably 30 seconds or higher, from the viewpoint of obtaining sufficient resin flowability; and is preferably 40 minutes or shorter, more preferably 35 minutes or shorter, and particularly preferably 30 minutes or shorter, from the viewpoint of suppressing resin viscosity increase during lamination.

[0025] When step (1) is performed by a vacuum lamination method, it is preferable to perform vacuum suction before pressurization for lamination, after the resin sheet and the substrate are superposed. In a preferred embodiment, the lamination method in step (1) involves superposing the resin sheet and the substrate, raising the temperature to a vacuum suction temperature, performing vacuum suction, and then applying pressure under vacuum without cooling the resin composition layer and the support to room temperature, thereby continuously performing vacuum suction and pressurization. The vacuum suction temperature before pressurization can be the same as or close to the heating temperature during lamination, and is preferably ±10°C, more preferably ±5°C, of ​​the heating temperature during lamination. The vacuum suction time before pressurization, which maintains the above vacuum suction temperature range, is preferably 0.5 minutes or more, more preferably 1 minute or more, particularly preferably 2 minutes or more, and preferably 40 minutes or less, more preferably 35 minutes or less, and particularly preferably 30 minutes or less.

[0026] After lamination in step (1), the laminated resin sheet may be smoothed under normal pressure (atmospheric pressure), for example, by pressing the support side with a thermocompression member. The pressing conditions for the smoothing treatment may be the same as those for the lamination. The smoothing treatment may be performed using a commercially available laminator. Note that the lamination and smoothing treatment may be performed consecutively using the commercially available vacuum laminator.

[0027] The thickness of the resin composition layer after lamination in step (1) is, for example, 100 μm or less, and from the viewpoint of thinning the wiring board, it is preferably 70 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less, and particularly preferably 40 μm or less, and from the viewpoint of ensuring sufficient insulation, it is preferably 5 μm or more, preferably 10 μm or more, preferably 13 μm or more, and preferably 15 μm or more.

[0028] Step (2) is a step of peeling the support from the resin composition layer, and is carried out after step (1).

[0029] The support may be peeled off manually or mechanically using an automatic peeling device in step (2). Examples of the method for peeling off the support in step (2) include a method of transporting the resin composition layer and the substrate while the support is fixed and peeling off the support, a method of pulling the support while the resin composition layer and the substrate are fixed and peeling off the support, and a method of transporting the resin composition layer and the substrate while pulling the support and peeling off the support, but are not limited to these as long as the support can be peeled off from the resin composition layer without damaging the resin composition layer.

[0030] The temperature conditions for peeling off the support in step (2) are not particularly limited, but it is preferably carried out at room temperature (preferably 10° C. to 40° C.) Peeling off the support is preferably carried out after cooling the substrate, resin composition layer, and support to room temperature after step (1).

[0031] The angle formed by the support peeling direction with respect to the surface of the resin composition layer when the support is peeled off in step (2) is not particularly limited, but is preferably 70° or less, more preferably 50° or less, and even more preferably 30° or less. The support peeling speed in step (2) is preferably 1 m / min to 20 m / min, more preferably 3 m / min to 10 m / min.

[0032] Step (3) is a step of heating and pressing a metal foil onto the resin composition layer using a vacuum hot press. Step (3) is carried out after step (2).

[0033] In step (3), the minimum melt viscosity of the resin composition layer before thermocompression bonding (particularly immediately before the metal foil is superimposed on the resin composition layer) is 2,000 to 20,000 poise. Here, the minimum melt viscosity refers to the minimum melt viscosity when the dynamic viscoelastic modulus is measured in a temperature range from 60°C to 200°C. The minimum melt viscosity of the resin composition layer before thermocompression bonding is preferably 3,000 poise or more, more preferably 4,000 poise or more, even more preferably 4,500 poise or more, and particularly preferably 5,000 poise or more, and the upper limit is preferably 17,000 poise or less, more preferably 15,000 poise or less, even more preferably 13,000 poise or less, and particularly preferably 12,000 poise or less, 11,000 poise or less, 10,000 poise or less, or 9,000 poise or less. The minimum melt viscosity of the resin composition layer before thermocompression bonding can be adjusted by the drying temperature, drying time, and drying method in any step (A) (drying step) described below, the vacuum suction time, vacuum suction temperature, heating temperature, pressurizing conditions, and heating and pressurizing time in step (1), or by selecting the components to be contained in the resin composition layer, etc. Preferably, the adjustment can be performed by step (A) (drying step).

[0034] From the perspective of achieving both good embedding property of the inner layer circuit during the lamination in step (1) and appropriate minimum melt viscosity in step (3), the minimum melt viscosity (V1) (poise) of the resin composition layer before lamination in step (1) is preferably lower than the minimum melt viscosity (V3) (poise) of the resin composition layer before thermocompression bonding in step (3) (V1 < V3). The relationship between the value of V1 (poise) and the value of V3 (poise) is more preferably V1 + 100 < V3, even more preferably V1 + 500 < V3, and particularly preferably V1 + 1000 < V3.

[0035] In step (3), the content of the organic solvent in the resin composition layer before thermocompression bonding (especially immediately before overlapping the metal foil with the resin composition layer) is, for example, 0 mass% or more when the total components in the resin composition layer are 100 mass%. From the perspective of favorably curing the resin composition layer, it is preferably 0.1 mass% or more, more preferably 0.2 mass% or more, even more preferably 0.3 mass% or more, and particularly preferably 0.4 mass% or more. From the perspective of suppressing the generation of voids in the resin composition layer, it is preferably 2.5 mass% or less, even more preferably 2.0 mass% or less, preferably 1.7 mass% or less, and preferably 1.5 mass% or less.

[0036] The metal used for the metal foil to be pressure-bonded in step (3) is not particularly limited. For example, it includes gold, silver, copper, aluminum, nickel, iron, chromium, manganese, molybdenum, and alloys containing at least 1 kind selected from these metals in a total of 90% or more. Particularly, copper is preferred from the viewpoints of thermal expansion coefficient, conductivity, and economy.

[0037] The thickness of the metal foil to be pressure-bonded in step (3) is not particularly limited, but is preferably 5 μm or less, more preferably 1 - 5 μm, and even more preferably 1.5 - 4 μm.

[0038] In one embodiment, a metal foil with a carrier may be used as the metal foil to be pressure-bonded in step (3). The metal foil with a carrier is a layered metal material including a carrier metal foil and a metal foil (thin metal foil) thinner than the carrier metal foil, which is peelably laminated on the carrier metal foil, if necessary via another film. When the metal foil with a carrier is used as the metal foil, the metal foil with a carrier can be superimposed so that the thin metal foil side is in contact with the resin composition layer, and then heat-pressed.

[0039] The metal used for the carrier metal foil in the carrier-attached metal foil is not particularly limited, but examples include gold, silver, copper, aluminum, nickel, iron, chromium, manganese, molybdenum, and alloys containing a total of 90% or more of at least one metal selected from these metals. Copper is particularly preferred in terms of thermal expansion coefficient, conductivity, and economy. The metal used for the thin metal foil in the carrier-attached metal foil may be the same as that used for the carrier metal foil. The metal used for the carrier metal foil and the metal used for the thin metal foil in the carrier-attached metal foil may be the same metal.

[0040] The thickness of the carrier metal foil in the carrier-attached metal foil is not particularly limited, but is preferably 5 to 60 μm, more preferably 10 to 30 μm. The thickness of the thin metal foil in the carrier-attached metal foil is not particularly limited, but is preferably 5 μm or less, more preferably 1 to 5 μm, and even more preferably 1.5 to 4 μm.

[0041] Commercially available carrier-attached metal foils include, for example, "MT18Ex" (carrier copper foil thickness 18 μm, thin copper foil thickness 2 μm) and "MT18FL" (carrier copper foil thickness 18 μm, thin copper foil thickness 3 μm) manufactured by Mitsui Mining & Smelting Co., Ltd.

[0042] The heating temperature during thermocompression bonding in step (3) is preferably 160°C or higher, more preferably 170°C or higher, even more preferably 180°C or higher, and particularly preferably 190°C or higher, from the viewpoint of sufficient thermal curing of the resin, and is preferably 250°C or lower, more preferably 240°C or lower, even more preferably 230°C or lower, and particularly preferably 220°C or lower, from the viewpoint of peelability of the metal foil. The pressure conditions during thermocompression bonding in step (3) are preferably 0.2MPa or higher, more preferably 0.3MPa or higher, even more preferably 0.4MPa or higher, and particularly preferably 0.5MPa or higher, from the viewpoint of sufficient adhesion to the metal foil, and are preferably 30MPa or lower, more preferably 20MPa or lower, even more preferably 10MPa or lower, even more preferably 5.0MPa or lower, and particularly preferably 2.0MPa or lower, from the viewpoint of resin film thickness uniformity after thermocompression bonding. The heating and pressing time during thermocompression bonding while maintaining the heating temperature and pressing conditions within the above ranges is preferably 30 minutes or more, more preferably 40 minutes or more, and particularly preferably 50 minutes or more, from the viewpoint of sufficient thermal curing of the resin, and is preferably 200 minutes or less, more preferably 180 minutes or less, and particularly preferably 150 minutes or less, from the viewpoint of productivity.

[0043] From the viewpoint of heat resistance reliability, the glass transition temperature of the resin composition layer after thermocompression in step (3) is preferably 130°C or higher, more preferably 135°C or higher, even more preferably 140°C or higher, even more preferably 145°C or higher, and particularly preferably 150°C or higher.

[0044] From the viewpoint of ensuring sufficient insulation, the thickness of the resin composition layer after thermocompression in step (3) is preferably greater than 10 μm, more preferably greater than 11 μm, even more preferably greater than 12 μm, still more preferably greater than 13 μm, even more preferably greater than 14 μm, and particularly preferably greater than 15 μm.

[0045] The thickness reduction rate of the resin composition layer after thermocompression bonding in step (3) relative to the resin composition layer before lamination in step (1) is preferably 58% or less, more preferably 55% or less, even more preferably 50% or less, still more preferably 45% or less, and particularly preferably 40% or less. The thickness reduction rate can be calculated as the percentage reduction in the thickness of the resin composition layer after thermocompression bonding in step (3) relative to the thickness of the resin composition layer before lamination in step (1).

[0046] In a preferred embodiment, the method for producing a wiring board of the present invention includes, after step (3), (4) forming a circuit pattern from a metal foil by a subtractive method.

[0047] In step (4), unnecessary portions of the metal foil that has been pressure-bonded to the resin composition layer in step (3) are selectively removed by etching or the like to form a circuit pattern.

[0048] In a preferred embodiment, step (4) includes (4a) a step of providing an etching resist on the metal foil, (4b) a step of etching the metal foil portions where the etching resist is not provided to remove unnecessary portions and form a circuit pattern from the metal foil, and (4c) a step of removing the etching resist. In step (4a), the etching resist may be provided by a method in which a resist resin layer is provided on the metal foil, a mask film is further provided on the resist resin layer, and then exposure and development are performed through the mask film.

[0049] In another preferred embodiment, the method for producing a wiring board of the present invention includes, after the step (3), a step (4′) of forming a circuit pattern from a metal foil by a modified semi-additive process.

[0050] In step (4'), a thick layer of metal is applied by electroplating to a portion (circuit formation portion) of the metal foil that has been pressure-bonded to the resin composition layer in step (3), and unnecessary portions of the metal foil are removed by etching or the like to form a circuit pattern.

[0051] In a preferred embodiment, step (4') includes the steps of (4a') providing a plating resist on a portion of the metal foil, (4b') electrolytic plating to thicken metal on the portions of the metal foil where the plating resist is not provided, (4c') removing the plating resist, and (4d') etching to remove the portions of the metal foil where the metal is not thickened, thereby forming a circuit pattern. In step (4a'), a resist resin layer may be provided on the metal foil, and a mask film may be provided on the resist resin layer, followed by exposure and development through the mask film.

[0052] In a preferred embodiment, the method for producing a wiring board of the present invention may further include a step of drying the resin composition layer (A) as an optional step performed after step (1) and before step (2), or after step (2) and before step (3). Drying may be performed by a known method such as heat drying, hot air blowing, or vacuum drying.

[0053] When step (A) is performed after step (1) and before step (2), the support is not removed in step (A), and the resin composition layer is dried through the support. From the viewpoint of suppressing adhesion of foreign matter to the resin composition layer, step (A) is preferably performed after step (1) and before step (2). When step (A) is performed after step (1) and before step (2), step (A) may be performed continuously from step (1) without cooling the resin composition layer and support to room temperature, or may be performed by temporarily cooling the resin composition layer and support to room temperature after step (1) and reheating. When step (A) is performed after step (2) and before step (3), step (A) may be performed continuously from step (2) without cooling the resin composition layer, or may be performed by temporarily cooling the resin composition layer to room temperature after step (2) and reheating.

[0054] The drying temperature in step (A) can be the same as or close to the heating temperature during lamination in step (1), and is preferably ±30°C, more preferably ±20°C, of ​​the heating temperature during lamination in step (1).

[0055] The drying temperature in step (A) is preferably 80° C. or higher, more preferably 90° C. or higher, even more preferably 100° C. or higher, particularly preferably 110° C. or higher, and preferably 160° C. or lower, more preferably 150° C. or lower, even more preferably 140° C. or lower, particularly preferably 130° C. or lower. The drying time for maintaining a drying temperature within the above range is preferably 1 minute or longer, more preferably 2 minutes or longer, particularly preferably 3 minutes or longer, and preferably 10 minutes or shorter, more preferably 8 minutes or shorter, particularly preferably 6 minutes or shorter.

[0056] It is preferable to perform step (A) from the viewpoint of simultaneously achieving circuit embedding properties of the inner layer circuit in step (1) and suppressing voids, suppressing changes in the thickness of the insulating layer, metal foil adhesion, and a good glass transition temperature in step (3). By performing step (A), the minimum melt viscosity of the resin composition layer in step (1) can be set relatively high in consideration of circuit embedding properties, and the amount of residual solvent can be reduced in step (A), making it possible to easily adjust the minimum melt viscosity of the resin composition layer before thermocompression bonding in step (3) to an appropriate range.

[0057] In a preferred embodiment, the method for producing a wiring board of the present invention includes, as an optional step carried out after step (3) and before step (4), (B) a step of forming a hole (e.g., a via hole) in the resin composition layer.

[0058] Step (B) may be performed by a known procedure using, for example, a drill, a laser, plasma, etc., depending on the composition of the resin composition layer, etc. The dimensions and shape of the holes (e.g., via holes, etc.) may be appropriately determined depending on the design of the wiring board.

[0059] In a preferred embodiment, the method for producing a wiring board of the present invention includes, as an optional step performed after step (B) and before step (4), (C) a step of performing a desmear treatment on holes formed in the resin composition layer.

[0060] In step (C), the procedure and conditions for the desmear treatment are not particularly limited, and known procedures and conditions that are usually used when forming a resin composition layer for a wiring board can be adopted. The desmear treatment is carried out, for example, by a method that includes a swelling treatment using a swelling liquid, a roughening treatment using an oxidizing agent, and a neutralization treatment using a neutralizing liquid.

[0061] The swelling liquid is not particularly limited, but examples thereof include alkaline solutions and surfactant solutions, and is preferably an alkaline solution, with sodium hydroxide solution and potassium hydroxide solution being more preferred. Commercially available swelling liquids include "Swelling Dip Securigance P" and "Swelling Dip Securigance SBU" manufactured by Atotech Japan. The swelling treatment using a swelling liquid is not particularly limited, but can be carried out, for example, by immersing the insulating layer in a swelling liquid at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing swelling of the resin in the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in a swelling liquid at 40°C to 80°C for 5 to 15 minutes.

[0062] The oxidizing agent is not particularly limited, but examples thereof include alkaline permanganate solutions prepared by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. Roughening treatment using an oxidizing agent such as alkaline permanganate solution is preferably carried out by immersing the insulating layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigance P" manufactured by Atotech Japan.

[0063] The neutralizing solution is preferably an acidic aqueous solution, and a commercially available product such as "Reduction Solution Securigant P" manufactured by Atotech Japan is an example.

[0064] Treatment with a neutralizing solution can be carried out by immersing the surface that has been roughened with an oxidizing agent in a neutralizing solution at 30° C. to 80° C. for 5 to 30 minutes. From the standpoint of workability, etc., a method in which the object that has been roughened with an oxidizing agent is immersed in a neutralizing solution at 40° C. to 70° C. for 5 to 20 minutes is preferred.

[0065] The wiring board manufactured by the wiring board manufacturing method of the present invention can be used in semiconductor devices, including various semiconductor devices used in electrical appliances (e.g., computers, mobile phones, digital cameras, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft).

[0066] <Resin composition layer> The components contained in the resin composition that forms the resin composition layer of the resin sheet used in step (1) will be described.

[0067] In a preferred embodiment, the resin composition layer of the resin sheet used in step (1) contains a thermosetting resin. Examples of thermosetting resins include epoxy resins, phenolic resins, thermosetting polyimide resins, cyanate ester resins, maleimide resins, benzoxazine resins, and thermosetting modified polyphenylene ether resins. The resin composition layer preferably contains a thermosetting resin selected from epoxy resins, cyanate ester resins, maleimide resins, and thermosetting modified polyphenylene ether resins, and more preferably a thermosetting resin selected from epoxy resins, maleimide resins, and thermosetting modified polyphenylene ether resins. Thermosetting resins also include epoxy resin curing agents and radical polymerization crosslinking agents that have the function of curing thermosetting resins through crosslinking reactions such as addition reactions and condensation reactions. One type of thermosetting resin may be used alone, or two or more types may be used in combination.

[0068] In one embodiment, the resin composition layer of the resin sheet used in step (1) preferably contains an epoxy resin as a thermosetting resin. One type of epoxy resin may be used alone, or two or more types may be used in combination. The epoxy resin is a curable resin having an epoxy group and an epoxy equivalent of 5,000 g / eq. or less.

[0069] Examples of epoxy resins include bixylenol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol AF-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol novolac-type epoxy resins, phenol novolac-type epoxy resins, tert-butyl-catechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ester-type epoxy resins, cresol novolac-type epoxy resins, phenol aralkyl-type epoxy resins, biphenyl-type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane-type epoxy resins, cyclohexane dimethanol-type epoxy resins, naphthylene ether-type epoxy resins, trimethylol-type epoxy resins, tetraphenylethane-type epoxy resins, isocyanurate-type epoxy resins, and phenolphthalimidine-type epoxy resins.

[0070] The resin composition layer of the resin sheet used in step (1) preferably contains an epoxy resin having two or more epoxy groups per molecule as the epoxy resin. The proportion of the epoxy resin having two or more epoxy groups per molecule relative to 100% by mass of the epoxy resin is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

[0071] There are two types of epoxy resins: those that are liquid at a temperature of 20°C (hereinafter referred to as "liquid epoxy resins"), and those that are solid at a temperature of 20°C (hereinafter referred to as "solid epoxy resins").

[0072] The resin composition layer of the resin sheet used in step (1) may contain only a liquid epoxy resin as the epoxy resin, or may contain only a solid epoxy resin, or may contain both a liquid epoxy resin and a solid epoxy resin, but it is particularly preferable that the resin composition layer contain both a liquid epoxy resin and a solid epoxy resin.

[0073] The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups in one molecule.

[0074] Preferred liquid epoxy resins include glycerol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol AF-type epoxy resins, naphthalene-type epoxy resins, glycidyl ester-type epoxy resins, glycidyl amine-type epoxy resins, phenol novolac-type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexanedimethanol-type epoxy resins, alicyclic glycidyl ethers, and epoxy resins having a butadiene structure.

[0075] Specific examples of liquid epoxy resins include "EX-992L" manufactured by Nagase ChemteX Corporation, "YX7400" manufactured by Mitsubishi Chemical Corporation, "HP4032", "HP4032D", and "HP4032SS" (naphthalene-type epoxy resins) manufactured by DIC Corporation; "828US", "jER828EL", "828EL", "825", and "Epikote 828EL" (bisphenol A-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; and "jER807" and "1750" ( Bisphenol F epoxy resin; Mitsubishi Chemical Corporation's "jER152" (phenol novolac epoxy resin); Mitsubishi Chemical Corporation's "630", "630LSD", and "604" (glycidylamine epoxy resin); ADEKA Corporation's "ED-523T" (glycirol epoxy resin); ADEKA Corporation's "EP-3950L" and "EP-3980S" (glycidylamine epoxy resin); ADEKA Corporation's "EP-4088S" (dicyclopentadiene epoxy resin); Nippon Steel Chemical & Material Corporation's "ZX1059" (mixture of bisphenol A and bisphenol F epoxy resins); Nagase ChemteX Corporation's "EX-721" (glycidyl ester epoxy resin); Nagase ChemteX Corporation's "EX-991L" (epoxy resin containing alkyleneoxy and butadiene skeletons); Daicel Corporation's "Celloxide 2021P" (alicyclic epoxy resin with ester skeleton) ); "PB-3600" manufactured by Daicel Corporation, "JP-100" and "JP-200" manufactured by Nippon Soda Co., Ltd. (epoxy resins having a butadiene structure); "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resins) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "EG-280" (fluorene structure-containing epoxy resin) manufactured by Osaka Gas Chemicals Co., Ltd.; and "EX-201" (cyclic aliphatic glycidyl ether) manufactured by Nagase ChemteX Corporation.

[0076] As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferred, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferred.

[0077] Preferred solid epoxy resins include bixylenol-type epoxy resins, naphthalene-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, naphthol novolac-type epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol AF-type epoxy resins, phenol aralkyl-type epoxy resins, tetraphenylethane-type epoxy resins, and phenolphthalimidine-type epoxy resins.

[0078] Specific examples of solid epoxy resins include "HP4032H" (naphthalene type epoxy resin) manufactured by DIC Corporation; "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resins) manufactured by DIC Corporation; "N-690" (cresol novolac type epoxy resin) manufactured by DIC Corporation; "N-695" (cresol novolac type epoxy resin) manufactured by DIC Corporation; "HP-7200", "HP-7200HH", "HP-7200H", and "HP-7200L" (dicyclopentadiene type epoxy resins) manufactured by DIC Corporation; and "EXA-7311" and "E" manufactured by DIC Corporation. XA-7311-G3, EXA-7311-G4, EXA-7311-G4S, HP6000, HP6000L (naphthylene ether type epoxy resin); Nippon Kayaku Co., Ltd.'s "EPPN-502H" (trisphenol type epoxy resin); Nippon Kayaku Co., Ltd.'s "NC7000L" (naphthol novolac type epoxy resin); Nippon Kayaku Co., Ltd.'s "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl type epoxy resin); Nippon Steel Chemical & Material Co., Ltd.'s "ESN475V", "ESN4100V" (naphthalene-type epoxy resin); "ESN485" (naphthol-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN375" (dihydroxynaphthalene-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YX4000HK", and "YL7890" (bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL6121" (biphenyl-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation. Examples include "YX7700" (phenol aralkyl type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals Co., Ltd.; "YL7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation; and "WHR991S" (phenolphthalimidine type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.These may be used alone or in combination of two or more.

[0079] When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin, the mass ratio thereof (liquid epoxy resin:solid epoxy resin) is preferably 10:1 to 1:50, more preferably 2:1 to 1:30, even more preferably 1:1 to 1:20, and particularly preferably 1:2 to 1:15.

[0080] The epoxy equivalent of the epoxy resin is preferably 50 g / eq. to 5,000 g / eq., more preferably 60 g / eq. to 2,000 g / eq., even more preferably 70 g / eq. to 1,000 g / eq., and even more preferably 80 g / eq. to 500 g / eq. The epoxy equivalent is the mass of the resin per equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0081] The weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight average molecular weight of the resin can be measured by gel permeation chromatography (GPC) as a polystyrene-equivalent value.

[0082] The content of the epoxy resin in the resin composition layer of the resin sheet used in step (1) is not particularly limited, but is preferably 1 to 50 mass% or less, more preferably 5 to 40 mass% or less, even more preferably 8 to 35 mass%, and particularly preferably 10 to 30 mass%, assuming that the non-volatile components in the resin composition layer are 100 mass%.

[0083] In one embodiment, when the resin composition layer of the resin sheet used in step (1) contains an epoxy resin as the thermosetting resin, it may further contain an epoxy resin curing agent as an optional component. The epoxy resin curing agent may be used alone or in any combination of two or more. When an epoxy resin is contained as the thermosetting resin, the epoxy resin curing agent may have the function of reacting with the epoxy resin to cure it.

[0084] The epoxy resin curing agent is not particularly limited, but examples thereof include active ester curing agents, phenolic curing agents, carbodiimide curing agents, acid anhydride curing agents, amine curing agents, benzoxazine curing agents, cyanate ester curing agents, and thiol curing agents. In one embodiment, the epoxy resin curing agent preferably contains one or more epoxy resin curing agents selected from active ester curing agents, phenolic curing agents, and cyanate ester curing agents. In one embodiment, the epoxy resin curing agent particularly preferably contains an active ester curing agent from the viewpoint of further reducing the dielectric loss tangent. In one embodiment, the epoxy resin curing agent particularly preferably contains a phenolic curing agent from the viewpoint of further improving curability.

[0085] As the active ester curing agent, compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are generally preferred. The active ester compound is preferably one obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. From the viewpoint of improving heat resistance in particular, an active ester compound obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester compound obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferred. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalene, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolak. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by condensing one dicyclopentadiene molecule with two phenol molecules.

[0086] Specific examples of the active ester curing agent include dicyclopentadiene-type active ester compounds containing a dicyclopentadiene-type diphenol structure, naphthalene-type active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated product of phenol novolac, and active ester compounds containing a benzoylated product of phenol novolac. Among these, at least one selected from dicyclopentadiene-type active ester compounds and naphthalene-type active ester compounds is more preferred.

[0087] Commercially available active ester curing agents include "EXB9451," "EXB9460," "EXB9460S," "HPC-8000L-65TM," "HPC-8000-65T," "HPC-8000H," and "HPC-8000H-65TM" (manufactured by DIC Corporation) as active ester compounds containing a dicyclopentadiene-type diphenol structure; and "HP-B-8151-62T," "EXB-8100L-65T," "EXB-9416-70BK," and "HPC-8150-62T" as active ester compounds containing a naphthalene structure. and "EXB-8" (manufactured by DIC Corporation); a phosphorus-containing active ester compound, "EXB9401" (manufactured by DIC Corporation); an active ester compound which is an acetylated product of phenol novolac, "DC808" (manufactured by Mitsubishi Chemical Corporation); active ester compounds which are benzoylated products of phenol novolac, "YLH1026," "YLH1030," and "YLH1048" (manufactured by Mitsubishi Chemical Corporation); an active ester compound containing a styryl group and a naphthalene structure, "PC1300-02-65MA" (manufactured by Air Water Inc.), and the like.

[0088] As the phenolic curing agent, a phenolic curing agent having a novolac structure is preferred from the viewpoint of heat resistance and water resistance. Also, from the viewpoint of adhesion to an adherend, a nitrogen-containing phenolic curing agent is preferred, and a triazine skeleton-containing phenolic curing agent is more preferred. Among them, a triazine skeleton-containing phenolic novolac resin is preferred from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion. Specific examples of phenolic curing agents include "MEH-7700," "MEH-7810," and "MEH-7851" manufactured by Meiwa Chemical Industry Co., Ltd.; "NHN," "CBN," and "GPH" manufactured by Nippon Kayaku Co., Ltd.; "SN-170," "SN-180," "SN-190," "SN-475," "SN-485," "SN-495," "SN-375," and "SN-395" manufactured by Nippon Steel Chemical & Material Co., Ltd.; and "LA-7052," "LA-7054," "LA-3018," "LA-3018-50P," "LA-1356," "TD2090," and "KA-1160" manufactured by DIC Corporation.

[0089] Examples of carbodiimide curing agents include curing agents having one or more, preferably two or more, carbodiimide structures in one molecule, such as aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexane-bis(methylene-t-butylcarbodiimide); aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide); and aliphatic polycarbodiimides such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylenebiscyclohexylenecarbodiimide), and poly(isophoronecarbodiimide). ; aromatic polycarbodiimides such as poly(phenylenecarbodiimide), poly(naphthylenecarbodiimide), poly(tolylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylenediphenylenecarbodiimide), and poly[methylenebis(methylphenylene)carbodiimide].

[0090] Commercially available carbodiimide curing agents include, for example, "Carbodilite V-02B," "Carbodilite V-03," "Carbodilite V-04K," "Carbodilite V-07," and "Carbodilite V-09" manufactured by Nisshinbo Chemical Inc.; and "Stavaxol P," "Stavaxol P400," and "Hykasil 510" manufactured by Rhein Chemie.

[0091] The acid anhydride curing agent may be a curing agent having one or more acid anhydride groups in one molecule, and a curing agent having two or more acid anhydride groups in one molecule is preferred. Specific examples of the acid anhydride curing agent include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic dianhydride. Examples of suitable anhydrides include anhydrides, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymeric anhydrides such as styrene-maleic acid resins, which are copolymers of styrene and maleic acid. Commercially available acid anhydride curing agents include "HNA-100," "MH-700," "MTA-15," "DDSA," and "OSA" manufactured by New Japan Chemical Co., Ltd.; "YH-306" and "YH-307" manufactured by Mitsubishi Chemical Corporation; "HN-2200" and "HN-5500" manufactured by Hitachi Chemical Co., Ltd.; and "EF-30," "EF-40," "EF-60," and "EF-80" manufactured by Clay Valley.

[0092] Examples of the amine curing agent include curing agents having one or more, preferably two or more, amino groups in one molecule, such as aliphatic amines, polyether amines, alicyclic amines, and aromatic amines, among which aromatic amines are preferred from the viewpoint of achieving the desired effects of the present invention. The amine curing agent is preferably a primary amine or a secondary amine, and more preferably a primary amine. Specific examples of amine-based curing agents include 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, and 2,2-bis(3-amino-4-hydroxyphenyl)propane. propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, and the like. Commercially available amine-based curing agents may be used, and examples thereof include "SEIKACURE-S" manufactured by Seika Corporation, "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD AA", "KAYAHARD AB", and "KAYAHARD AS" manufactured by Nippon Kayaku Co., Ltd., and "Epicure W" manufactured by Mitsubishi Chemical Corporation.

[0093] Specific examples of benzoxazine curing agents include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Corporation; "HFB2006M" manufactured by Showa Polymer Co., Ltd.; and "Pd" and "Fa" manufactured by Shikoku Chemicals Corporation.

[0094] Examples of cyanate ester curing agents include bifunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate)), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, and bis(4-cyanatephenyl)ether; multifunctional cyanate resins derived from phenol novolac and cresol novolac; and prepolymers in which these cyanate resins are partially converted to triazine. Specific examples of cyanate ester curing agents include "PT30" and "PT60" (both phenol novolac type multifunctional cyanate ester resins) manufactured by Lonza Japan Co., Ltd., "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate has been triazine converted to a trimer).

[0095] Examples of thiol-based curing agents include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris(3-mercaptopropyl)isocyanurate.

[0096] The epoxy reactive group equivalent of the epoxy resin curing agent is preferably 50 g / eq. to 3000 g / eq., more preferably 100 g / eq. to 1000 g / eq., even more preferably 100 g / eq. to 500 g / eq., and particularly preferably 100 g / eq. to 300 g / eq. The epoxy reactive group equivalent is the mass of the epoxy resin curing agent per equivalent of the epoxy reactive group.

[0097] The content of the epoxy resin curing agent in the resin composition layer of the resin sheet used in step (1) is not particularly limited, but is preferably 0.1 to 30 mass%, more preferably 1 to 25 mass%, even more preferably 3 to 20 mass%, and particularly preferably 5 to 15 mass%, assuming that the non-volatile components in the resin composition layer are 100 mass%.

[0098] In one embodiment, the resin composition layer of the resin sheet used in step (1) preferably contains a thermosetting modified polyphenylene ether resin as the thermosetting resin. The thermosetting modified polyphenylene ether resin preferably contains a modified polyphenylene ether resin having two or more radical reactive groups. The thermosetting modified polyphenylene ether resin may be used alone or in combination of two or more.

[0099] The radical reactive group is a group having a radical reactive ethylenically unsaturated bond, and examples thereof include, but are not limited to, (1) an acryloyl group, (2) a methacryloyl group, (3) an allyl group, (4) a methallyl group, (5) a phenyl group substituted with a group selected from a vinyl group and an isopropenyl group and which may further be substituted with an alkyl group (for example, a vinylphenyl group (i.e., a 4-vinylphenyl group, a 3-vinylphenyl group, a 2-vinylphenyl group), an isopropenylphenyl group (i.e., a 4-isopropylphenyl group), a 2-isopropylphenyl group), a 2-isopropylphenyl group, ... (6) benzyl groups substituted with a group selected from a vinyl group and an isopropenyl group and which may further be substituted with an alkyl group (for example, vinylbenzyl groups (i.e., 4-vinylbenzyl groups, 3-vinylbenzyl groups, 2-vinylbenzyl groups), isopropenylbenzyl groups (i.e., 4-isopropenylbenzyl groups, 3-isopropenylbenzyl groups, 2-isopropenylbenzyl groups), etc.).

[0100] The alkyl group refers to a linear, branched, and / or cyclic monovalent aliphatic saturated hydrocarbon group. Unless otherwise specified, the alkyl group is preferably an alkyl group having 1 to 14 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a neopentyl group, a tert-pentyl group, a hexyl group, an isohexyl group, a heptyl group, an isoheptyl group, an octyl group, an isooctyl group, a tert-octyl group, a cyclopentyl group, a cyclohexyl group, and a cyclohexylmethyl group.

[0101] In one embodiment, the thermosetting modified polyphenylene ether resin is particularly preferably a polyphenylene ether resin represented by formula (1):

[0102] [ka]

[0103] [In the formula, R 11 and R 12 each independently represents an alkyl group; R 13 , R 14 , R 21 , R 22 , R 23 and R 24 each independently represents a hydrogen atom or an alkyl group; R a and R b each independently represent (1) an acryloyl group, (2) a methacryloyl group, (3) an allyl group, (4) a methallyl group, (5) a phenyl group substituted with a group selected from a vinyl group and an isopropenyl group and which may further be substituted with an alkyl group, or (6) a benzyl group substituted with a group selected from a vinyl group and an isopropenyl group and which may further be substituted with an alkyl group; X 1 is a single bond, -C(Rc )2-, -O-, -CO-, -S-, -SO-, or -SO2-; R c each independently represents a hydrogen atom or an alkyl group; s represents 0 or 1; t and u each independently represent an integer of 1 or more. The t units and u units may be the same or different for each unit.

[0104] R 11 and R 12 R each independently represents an alkyl group, and in one embodiment, is preferably a methyl group. 13 and R 14 R each independently represents a hydrogen atom or an alkyl group, and in one embodiment, is preferably a hydrogen atom. 21 and R 22 R each independently represents a hydrogen atom or an alkyl group, and in one embodiment, is preferably a hydrogen atom or a methyl group, and more preferably a methyl group. 23 and R 24 each independently represents a hydrogen atom or an alkyl group, and in one embodiment, is preferably a hydrogen atom or a methyl group.

[0105] R a and R b each independently represents (1) an acryloyl group, (2) a methacryloyl group, (3) an allyl group, (4) a methallyl group, (5) a phenyl group substituted with a group selected from a vinyl group and an isopropenyl group and which may further be substituted with an alkyl group, or (6) a benzyl group substituted with a group selected from a vinyl group and an isopropenyl group and which may further be substituted with an alkyl group.

[0106] R a and R bare each independently preferably (1) a phenyl group substituted with a group selected from a vinyl group and an isopropenyl group and optionally further substituted with an alkyl group, or (2) a benzyl group substituted with a group selected from a vinyl group and an isopropenyl group and optionally further substituted with an alkyl group; more preferably a 4-vinylphenyl group, a 3-vinylphenyl group, a 2-vinylphenyl group, a 4-isopropenylphenyl group, a 3-isopropenylphenyl group, a 2-isopropenylphenyl group, a 4-vinylbenzyl group, a 3-vinylbenzyl group, a 2-vinylbenzyl group, a 4-isopropenylbenzyl group, a 3-isopropenylbenzyl group, or a 2-isopropenylbenzyl group; particularly preferably a 4-vinylbenzyl group, a 3-vinylbenzyl group, or a 2-vinylbenzyl group.

[0107] X 1 is a single bond, -C(R c )2-, -O-, -CO-, -S-, -SO-, or -SO2-, and in one embodiment, preferably represents a single bond, -C(R c )2- or -O-. c each independently represents a hydrogen atom or an alkyl group, and in one embodiment, is preferably a hydrogen atom or a methyl group.

[0108] s represents 0 or 1, and in one embodiment, is preferably 1. t and u each independently represent an integer of 1 or more, and in one embodiment, is preferably an integer of 1 to 200, and more preferably an integer of 1 to 100.

[0109] The radical reactive group equivalent of the thermosetting modified polyphenylene ether resin is preferably 300 g / eq. to 2500 g / eq., more preferably 400 g / eq. to 2000 g / eq. The radical reactive group equivalent represents the mass of the resin (compound) per equivalent of the radical reactive group.

[0110] The number average molecular weight of the thermosetting modified polyphenylene ether resin is preferably 800 to 10,000, more preferably 900 to 5,000, and even more preferably 1,000 to 2,500. The number average molecular weight of the resin can be measured by gel permeation chromatography (GPC) as a polystyrene-equivalent value.

[0111] Commercially available thermosetting modified polyphenylene ether resins include, for example, "OPE-2St 1200" and "OPE-2St 2200" (vinylbenzyl-modified polyphenylene ether resins) manufactured by Mitsubishi Gas Chemical Company, Inc.; and "SA9000" and "SA9000-111" (methacrylic-modified polyphenylene ether resins) manufactured by SABIC Innovative Plastics.

[0112] The content of the thermosetting modified polyphenylene ether resin in the resin composition layer of the resin sheet used in step (1) is not particularly limited, but is preferably 0.1 to 40 mass% or less, more preferably 1 to 20 mass% or less, even more preferably 3 to 15 mass%, and particularly preferably 5 to 10 mass%, assuming that the non-volatile components in the resin composition layer are 100 mass%.

[0113] In one embodiment, the resin composition layer of the resin sheet used in step (1) preferably contains a maleimide resin as a thermosetting resin. The maleimide resin refers to a curable resin containing at least one maleimide group (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl group) per molecule. One type of maleimide resin may be used alone, or two or more types may be used in combination.

[0114] In the first embodiment, the maleimide resin is preferably a compound represented by formula (2'):

[0115] [ka]

[0116] [In the formula, Ring B represents an optionally substituted monocycloalkane ring or an optionally substituted monocycloalkene ring; i and j each independently represent an integer of 0 or 1 or greater, and the sum of i and j is 6 or greater; * indicates the binding site.] The number of maleimide groups in one molecule of the maleimide compound in the first embodiment is preferably 2 or more, and particularly preferably 2. The maleimide compounds in the first embodiment may be used singly or in combination of two or more at any ratio.

[0117] The "substituent" in ring B of formula (2') is not particularly limited, and examples thereof include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, and an aralkyl-oxy group.

[0118] The halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0119] The term "alkenyl group" refers to a linear, branched, and / or cyclic monovalent aliphatic unsaturated hydrocarbon group having at least one carbon-carbon double bond. Unless otherwise specified, the alkenyl group is preferably an alkenyl group having 2 to 14 carbon atoms, more preferably an alkenyl group having 2 to 6 carbon atoms, and even more preferably an alkenyl group having 2 or 3 carbon atoms. Examples of alkenyl (groups) include vinyl groups, propenyl groups (allyl groups, 1-propenyl groups, isopropenyl groups), butenyl groups (1-butenyl groups, crotyl groups, methallyl groups, isocrotyl groups, etc.), pentenyl groups (1-pentenyl groups, etc.), hexenyl groups (1-hexenyl groups, etc.), heptenyl groups (1-heptenyl groups, etc.), octenyl groups (1-octenyl groups, etc.), cyclopentenyl groups (2-cyclopentenyl groups, etc.), and cyclohexenyl groups (3-cyclohexenyl groups).

[0120] The aryl (group) refers to a monovalent aromatic hydrocarbon group formed by removing one hydrogen atom from an aromatic carbon ring. Unless otherwise specified, the aryl (group) is preferably an aryl (group) having 6 to 14 carbon atoms, more preferably an aryl (group) having 6 to 10 carbon atoms. Examples of the aryl (group) include a phenyl group, a 1-naphthyl group, and a 2-naphthyl group.

[0121] The term "aralkyl group" refers to an alkyl group substituted with one or more (preferably one) aryl groups. Unless otherwise specified, the aralkyl group is preferably an aralkyl group having 7 to 15 carbon atoms, more preferably an aralkyl group having 7 to 11 carbon atoms. Examples of the aralkyl group include a benzyl group, a phenethyl group, a hydrocinnamyl group, an α-methylbenzyl group, an α-cumyl group, a 1-naphthylmethyl group, and a 2-naphthylmethyl group.

[0122] The monocycloalkane ring refers to a monocyclic aliphatic saturated hydrocarbon ring. The monocycloalkane ring is preferably a monocycloalkane ring having 4 to 14 carbon atoms, more preferably a monocycloalkane ring having 4 to 10 carbon atoms, and particularly preferably a monocycloalkane ring having 5 or 6 carbon atoms. Examples of the monocycloalkane ring include a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, and a cyclooctane ring. The monocycloalkene ring refers to a monocyclic aliphatic unsaturated hydrocarbon ring having at least one carbon-carbon double bond. The monocycloalkene ring is preferably a monocycloalkene ring having 4 to 14 carbon atoms, more preferably a monocycloalkene ring having 4 to 10 carbon atoms, and particularly preferably a monocycloalkene ring having 5 or 6 carbon atoms. Examples of the monocycloalkene ring include a cyclobutene ring, a cyclopentene ring, a cyclohexene ring, a cycloheptene ring, a cyclooctene ring, a cyclopentadiene ring, and a cyclohexadiene ring.

[0123] Ring B represents a monocycloalkane ring which may have a substituent, or a monocycloalkene ring which may have a substituent. Ring B is preferably a monocycloalkane ring which may have a substituent selected from an alkyl group and an alkenyl group; or a monocycloalkene ring which may have a group selected from an alkyl group and an alkenyl group. Ring B is more preferably a monocycloalkane ring which may have a substituent selected from an alkyl group having 1 to 14 carbon atoms and an alkenyl group having 2 to 14 carbon atoms; or a monocycloalkene ring which may have a group selected from an alkyl group having 1 to 14 carbon atoms and an alkenyl group having 2 to 14 carbon atoms.

[0124] i and j each independently represent an integer of 0 or 1 or more, and the sum of i and j is 6 or more (preferably 8 or more, more preferably 10 or more). i and j are preferably each independently an integer of 0 to 20, and the sum of i and j is 6 or more (preferably 8 or more, more preferably 10 or more). i and j are more preferably each independently an integer of 1 to 20, and the sum of i and j is 6 or more (preferably 8 or more, more preferably 10 or more). i and j are further preferably each independently an integer of 5 to 10. i and j are particularly preferably 8.

[0125] In the first embodiment, the maleimide resin is particularly preferably a maleimide resin represented by formula (2):

[0126] [ka]

[0127] [In the formula, R 10 each independently represents a substituent; ring C independently represents an aromatic ring which may have a substituent; D 1 and D 2 are each independently a single bond, -C(R x)2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, -NHCO-, -COO-, or -OCO-; R x each independently represents a hydrogen atom or an alkyl group; c's each independently represent 0 or 1; Each d independently represents an integer of 0 or 1 or more; e each independently represents 0, 1, or 2; n represents an integer of 0 or 1 or more; Other symbols are as above.] The d unit, the e unit, and the n unit may be the same or different for each unit.

[0128] R in Equation (2) 10 and the "substituent" in ring C are not particularly limited, and examples thereof include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, and an aralkyl-oxy group.

[0129] The aromatic ring refers to a ring that conforms to Hückel's rule, in which the number of electrons contained in the π-electron system on the ring is 4p+2 (p is a natural number). The aromatic ring may be an aromatic carbocyclic ring containing only carbon atoms as ring-constituting atoms, or an aromatic heterocyclic ring containing heteroatoms such as oxygen atoms, nitrogen atoms, and sulfur atoms in addition to carbon atoms as ring-constituting atoms. In one embodiment, the aromatic ring is preferably an aromatic carbocyclic ring. In one embodiment, the aromatic ring is preferably a 5- to 14-membered aromatic ring, more preferably a 6- to 14-membered aromatic ring, and even more preferably a 6- to 10-membered aromatic ring. Specific examples of suitable aromatic rings include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring. A benzene ring or a naphthalene ring is more preferred, and a benzene ring is particularly preferred.

[0130] Each ring C independently represents an aromatic ring which may have a substituent, and is preferably a benzene ring which may have a substituent selected from alkyl groups.

[0131] D 1 and D 2 are each independently a single bond, -C(R x )2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, -NHCO-, -COO-, or -OCO-, and preferably represents a single bond, -C(R x )2- or -O-. x each independently represents a hydrogen atom or an alkyl group, and is preferably a hydrogen atom or a methyl group.

[0132] Each c independently represents 0 or 1, preferably 0. Each d independently represents 0 or an integer of 1 or more, preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. Each e independently represents 0, 1, or 2, preferably 0. Each n independently represents 0 or an integer of 1 or more, preferably 0.

[0133] Formula (D) contained in formula (2):

[0134] [ka]

[0135] [In the formula, * indicates a binding site; other symbols are as defined above.] The partial structure represented by the formula (D-1) to (D-3):

[0136] [ka]

[0137] [In the formula, * is the same as above.] Examples of the partial structure include:

[0138] The maleimide group equivalent of the maleimide resin in the first embodiment is preferably 200 g / eq. to 2500 g / eq., more preferably 250 g / eq. to 2000 g / eq., and even more preferably 300 g / eq. to 1500 g / eq. The maleimide group equivalent of the maleimide resin represents the mass of the resin per 1 equivalent of the maleimide group.

[0139] The weight average molecular weight of the maleimide resin in the first embodiment is preferably 400 to 10,000, more preferably 500 to 7,000, and particularly preferably 600 to 5,000.

[0140] Commercially available maleimide resins according to the first embodiment include, for example, "BMI-689," "BMI-1500," "BMI-1700," and "BMI-3000J" manufactured by Designer Molecules, Inc., and "SLK-6895-T90" manufactured by Shin-Etsu Chemical Co., Ltd.

[0141] In the second embodiment, the maleimide resin is preferably a maleimide resin represented by formula (3):

[0142] [ka]

[0143] [In the formula, R 20 each independently represents a hydrogen atom or an alkyl group; Ring E, ring F, and ring G each independently represent an aromatic ring which may have a substituent; Z 1 are each independently a single bond, -C(R z )2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, or -NHCO-; R z each independently represents a hydrogen atom or an alkyl group; f represents an integer equal to or greater than 1; g's each independently represent 0 or 1; Each h independently represents 0, 1, 2, or 3. The f units and h units may be the same or different for each unit. The maleimide compounds in the second embodiment may be used singly or in combination of two or more types in any ratio.

[0144] The "substituents" in ring E, ring F, and ring G in formula (3) are not particularly limited, and examples thereof include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, and an aralkyl-oxy group.

[0145] R 20 are each independently a hydrogen atom or an alkyl group, preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0146] Ring E, ring F, and ring G each independently represent an aromatic ring which may have a substituent, preferably a benzene ring which may have a substituent, more preferably a benzene ring which may be substituted with a group selected from an alkyl group and an aryl group, and particularly preferably an (unsubstituted) benzene ring.

[0147] Z 1 are each independently a single bond, -C(R z )2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, or -NHCO-, and preferably a single bond. z each independently represents a hydrogen atom or an alkyl group, and is preferably a hydrogen atom or a methyl group.

[0148] f represents an integer of 1 or more, and preferably an integer of 1 to 10. g's each independently represent 0 or 1, and preferably 1. h's each independently represent 0, 1, 2, or 3, and preferably 0, 1, or 2, more preferably 0 or 1, and particularly preferably 1.

[0149] The maleimide group equivalent of the maleimide resin in the second embodiment is preferably 150 g / eq. to 1000 g / eq., and more preferably 200 g / eq. to 500 g / eq.

[0150] The weight average molecular weight of the maleimide resin in the second embodiment is preferably 100 to 10,000, more preferably 150 to 5,000, and particularly preferably 200 to 3,000.

[0151] Commercially available maleimide resins in the second embodiment include, for example, "MIR-3000-70MT" and "MIR-5000-60T" manufactured by Nippon Kayaku Co., Ltd.

[0152] In the third embodiment, the maleimide resin is preferably a maleimide resin represented by formula (4):

[0153] [ka]

[0154] [In the formula, R 30 each independently represents an alkyl group; Ring H and ring I each independently represent an aromatic ring which may have a substituent; m represents an integer of 1 or greater. The m units may be the same or different for each unit. The maleimide compounds in the third embodiment may be used singly or in combination of two or more types in any ratio.

[0155] The "substituents" in ring H and ring I of formula (4) are not particularly limited, and examples thereof include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, and an aralkyl-oxy group.

[0156] R30 are each independently an alkyl group, and in one embodiment, preferably a methyl group. Ring H is each independently an aromatic ring which may have a substituent, and in one embodiment, is preferably a benzene ring which may have a substituent, more preferably a benzene ring which may have a substituent selected from alkyl groups, and even more preferably a benzene ring substituted with a group selected from alkyl groups.

[0157] Each ring I independently represents an aromatic ring which may have a substituent, and in one embodiment, is preferably a benzene ring which may have a substituent, more preferably a benzene ring which may be substituted with a group selected from alkyl groups, and even more preferably an (unsubstituted) benzene ring. m represents an integer of 1 or more, and preferably an integer of 1 to 20.

[0158] The maleimide resin in the third embodiment can be produced, for example, by using the method described in the Japan Institute of Invention and Innovation's Disclosure Technical Bulletin No. 2020-500211 or a method equivalent thereto.

[0159] The maleimide resin may contain any one of the preferred compounds in the first embodiment, the preferred compounds in the second embodiment, and the preferred compounds in the third embodiment, alone, or may contain two or more of these in combination at any ratio.

[0160] The maleimide group equivalent of the maleimide resin is preferably 30 g / eq. to 2500 g / eq., and particularly preferably 75 g / eq. to 2000 g / eq.

[0161] The content of the maleimide resin in the resin composition layer of the resin sheet used in step (1) is not particularly limited, but is preferably 5 to 50 mass%, more preferably 10 to 40 mass%, even more preferably 15 to 35 mass%, and particularly preferably 20 to 30 mass%, assuming that the non-volatile components in the resin composition are 100 mass%.

[0162] In one embodiment, the resin composition layer of the resin sheet used in step (1) may contain a radical polymerizable crosslinking agent as a thermosetting resin.

[0163] The radically polymerizable crosslinking agent is preferably a low molecular weight compound (e.g., a molecular weight of less than 800) having two or more radically reactive groups. Examples of such compounds include polyfunctional (meth)acryloyl group-containing compounds, polyfunctional vinylphenyl group-containing compounds, and polyfunctional (meth)allyl group-containing compounds.

[0164] The polyfunctional (meth)acryloyl group-containing compound is a compound having two or more acryloyl groups or methacryloyl groups. Examples of polyfunctional (meth)acryloyl group-containing compounds include aliphatic (meth)acrylic acid ester compounds such as cyclohexane-1,4-dimethanol di(meth)acrylate, cyclohexane-1,3-dimethanol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, glycerin tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate; dioxane glycol Examples of the ether-containing (meth)acrylic acid ester compounds include di(meth)acrylate, 3,6-dioxa-1,8-octanediol di(meth)acrylate, 3,6,9-trioxaundecane-1,11-diol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, ethoxylated bisphenol A di(meth)acrylate, and propoxylated bisphenol A di(meth)acrylate; and isocyanurate-containing (meth)acrylic acid ester compounds such as tris(3-hydroxypropyl)isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, and ethoxylated isocyanuric acid tri(meth)acrylate.Examples of commercially available polyfunctional (meth)acryloyl group-containing compounds include "A-DOG" (dioxane glycol diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., "DCP-A" (tricyclodecane dimethanol diacrylate) and "DCP" (tricyclodecane dimethanol dimethacrylate) manufactured by Kyoeisha Chemical Co., Ltd., and "KAYARAD R-684" (tricyclodecane dimethanol diacrylate) and "KAYARAD R-604" (dioxane glycol diacrylate) manufactured by Nippon Kayaku Co., Ltd.

[0165] The polyfunctional vinylphenyl group-containing compound is a compound having two or more vinylphenyl groups. Examples of the polyfunctional vinylphenyl group-containing compound having a molecular weight of less than 800 include 4,4'-divinylbiphenyl, 1,2-bis(4-vinylphenyl)ethane, 2,2-bis(4-vinylphenyl)propane, and bis(4-vinylphenyl)ether.

[0166] The polyfunctional (meth)allyl group-containing compound is a compound having two or more allyl groups or methallyl groups. Examples of polyfunctional (meth)allyl group-containing compounds include aromatic carboxylic acid allyl ester compounds such as diallyl diphenate, triallyl trimellitate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl 2,6-naphthalenedicarboxylate, and diallyl 2,3-naphthalenecarboxylate; isocyanuric acid allyl ester compounds such as 1,3,5-triallyl isocyanurate and 1,3-diallyl-5-glycidyl isocyanurate; epoxy-containing aromatic allyl compounds such as 2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane; benzoxazine-containing aromatic allyl compounds such as bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane; ether-containing aromatic allyl compounds such as 1,3,5-triallyl ether benzene; and allyl silane compounds such as diallyldiphenylsilane. Commercially available polyfunctional (meth)allyl group-containing compounds with a molecular weight of less than 800 include "TAIC" (1,3,5-triallyl isocyanurate) manufactured by Nippon Kasei Chemical Industry Co., Ltd., "DAD" (diallyl diphenate) manufactured by Nisshoku Techno Fine Chemical Co., Ltd., "TRIAM-705" (triallyl trimellitate) manufactured by Wako Pure Chemical Industries, Ltd., "DAND" (2,3-diallyl naphthalenecarboxylate) manufactured by Nippon Distillation Industry Co., Ltd., "ALP-d" (bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane) manufactured by Shikoku Chemical Industry Co., Ltd., "RE-810NM" (2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane) manufactured by Nippon Kayaku Co., Ltd., and "DA-MGIC" (1,3-diallyl-5-glycidyl isocyanurate) manufactured by Shikoku Chemical Industry Co., Ltd.

[0167] In one embodiment, the radically polymerizable crosslinking agent is particularly preferably represented by formula (5):

[0168] [ka]

[0169] [In the formula, R d and R e each independently represent (1) an acryloyl group, (2) a methacryloyl group, (3) an allyl group, (4) a methallyl group, (5) a phenyl group substituted with a group selected from a vinyl group and an isopropenyl group and which may further be substituted with an alkyl group, or (6) a benzyl group substituted with a group selected from a vinyl group and an isopropenyl group and which may further be substituted with an alkyl group; X 2 and X 3 represents a single bond or an alkylene group; Ring A is an optionally substituted non-aromatic carbocyclic ring or an optionally substituted non-aromatic heterocyclic ring. The compound includes a low molecular weight compound (for example, a molecular weight of less than 800) represented by the formula:

[0170] The "substituent" included in the definition of the symbol in formula (5) is not particularly limited, and examples thereof include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, and an aralkyl-oxy group.

[0171] R d and R e R each independently represents (1) an acryloyl group, (2) a methacryloyl group, (3) an allyl group, (4) a methallyl group, (5) a phenyl group substituted with a group selected from a vinyl group and an isopropenyl group and which may further be substituted with an alkyl group, or (6) a benzyl group substituted with a group selected from a vinyl group and an isopropenyl group and which may further be substituted with an alkyl group. d and R e In one embodiment, each of is independently preferably an acryloyl group or a methacryloyl group.

[0172] X 2 and X 3represents a single bond or an alkylene group. The alkylene group refers to a straight-chain and / or branched-chain divalent aliphatic saturated hydrocarbon group. The alkylene group is preferably an alkylene group having 1 to 6 carbon atoms. Examples of the alkylene group include -CH2-, -CH2-CH2-, -CH(CH3)-, -CH2-CH2-CH2-, -CH2-CH(CH3)-, -CH(CH3)-CH2-, -C(CH3)2-, -CH2-CH2-CH2-CH2-, -CH2-CH2-CH(CH3)-, -CH2-CH(CH3)-CH2-, -CH(CH3)-CH2-CH2-, -C(CH3)2-CH2-, and -CH2-C(CH3)2-. X 2 and X 3 In one embodiment, each independently is preferably an alkylene group.

[0173] Ring A is an optionally substituted non-aromatic carbocyclic ring or an optionally substituted non-aromatic heterocyclic ring.

[0174] A non-aromatic carbocycle refers to a ring whose ring constituent atoms are solely carbon atoms that are not aromatic throughout the ring. The non-aromatic carbocycle may be a monocyclic non-aromatic carbocycle or a polycyclic non-aromatic carbocycle. The non-aromatic carbocycle may be a saturated carbocycle consisting of only single bonds, or an unsaturated carbocycle having a double bond in addition to a single bond. The non-aromatic carbocycle is preferably a 3- to 21-membered non-aromatic carbocycle, more preferably a 4- to 18-membered non-aromatic carbocycle, and even more preferably a 5- to 14-membered non-aromatic carbocycle. Specific preferred examples of the non-aromatic carbocycle include monocyclic saturated carbocycles such as a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a cyclononane ring, a cyclodecane ring, a cycloundecane ring, and a cyclododecane ring; bicyclic saturated carbocycles such as a bicyclo[2.2.1]heptane ring (norbornane ring), a bicyclo[4.4.0]decane ring (decalin ring), a bicyclo[5.3.0]decane ring, a bicyclo[4.3.0]nonane ring (hydrindane ring), a bicyclo[3.2.1]octane ring, a bicyclo[5.4.0]undecane ring, a bicyclo[3.3.0]octane ring, and a bicyclo[3.3.1]nonane ring; 2,6] Decane ring (tetrahydrodicyclopentadiene ring), tricyclo[3.3.1.1 3,7 ] Decane ring (adamantane ring), tricyclo[6.2.1.0 2,7 ]undecane ring and other saturated tricyclic carbocyclic rings.

[0175] A non-aromatic heterocycle refers to a ring that does not have aromaticity throughout the ring and has heteroatoms such as oxygen, nitrogen, and sulfur atoms in addition to carbon atoms as ring-constituting atoms. The non-aromatic heterocycle may be a monocyclic non-aromatic heterocycle or a polycyclic non-aromatic heterocycle. The non-aromatic heterocycle may be a saturated heterocycle consisting of only a single bond, or an unsaturated heterocycle having a double bond in addition to a single bond. The non-aromatic heterocycle is preferably a 3- to 21-membered non-aromatic heterocycle, more preferably a 4- to 18-membered non-aromatic heterocycle, and even more preferably a 5- to 14-membered non-aromatic heterocycle. Specific examples of suitable non-aromatic heterocycles include a 1,3-dioxane ring, a 1,3-dioxolane ring, a tetrahydropyran ring, and a tetrahydrofuran ring.

[0176] In one embodiment, ring A is preferably a non-aromatic carbocycle optionally substituted with an alkyl group or a non-aromatic heterocycle optionally substituted with an alkyl group; more preferably a tetrahydrodicyclopentadiene ring optionally substituted with an alkyl group or a 1,3-dioxane ring optionally substituted with an alkyl group.

[0177] The radically reactive group equivalent of the radically polymerizable crosslinking agent is preferably 30 g / eq. to 400 g / eq., more preferably 50 g / eq. to 300 g / eq., and even more preferably 75 g / eq. to 200 g / eq.

[0178] The molecular weight of the radically polymerizable crosslinking agent is preferably 100-700, more preferably 200-400, and even more preferably 250-500.

[0179] The content of the radical polymerizable crosslinking agent in the resin composition layer of the resin sheet used in step (1) is not particularly limited, but is preferably 0.1 to 40 mass % or less, more preferably 1 to 20 mass % or less, even more preferably 3 to 15 mass %, and particularly preferably 5 to 10 mass %, assuming that the non-volatile components in the resin composition layer are 100 mass %.

[0180] The content of the thermosetting resin in the resin composition layer of the resin sheet used in step (1) is not particularly limited, but is preferably 1 to 60 mass % or less, more preferably 10 to 50 mass % or less, even more preferably 15 to 45 mass %, and particularly preferably 20 to 40 mass %, assuming that the non-volatile components in the resin composition layer are 100 mass %.

[0181] In a preferred embodiment, the resin composition layer of the resin sheet used in step (1) may contain an inorganic filler. The inorganic filler is present in the form of particles in the resin composition layer.

[0182] As the inorganic filler material, an inorganic compound is used. Examples of inorganic filler materials include silica, alumina, aluminosilicate, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium titanate zirconate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica, alumina, or aluminosilicate is preferred, and silica is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Furthermore, spherical silica is preferred. The inorganic filler may be used alone or in combination of two or more kinds in any ratio.

[0183] Commercially available inorganic fillers include, for example, "SP60-05" and "SP507-05" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YC100C," "YA050C," "YA050C-MJE," "YA010C," "SC2500SQ," "SO-C4," "SO-C2," and "SO-C1" manufactured by Admatechs Co., Ltd.; "UFP-30," "DAW-03," and "FB-105FD" manufactured by Denka Co., Ltd.; "Silfil NSS-3N," "Silfil NSS-4N," and "Silfil NSS-5N" manufactured by Tokuyama Corporation; "Cellphears" and "MGH-005" manufactured by Taiheiyo Cement Corporation; and "Sferique" and "BA-1" manufactured by JGC Catalysts and Chemicals Co., Ltd.

[0184] The average particle size of the inorganic filler is not particularly limited, but is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less, even more preferably 1 μm or less, and particularly preferably 0.8 μm or less. The lower limit of the average particle size of the inorganic filler is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and particularly preferably 0.2 μm or more. The average particle size of the inorganic filler can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, a particle size distribution of the inorganic filler is created on a volume basis using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is used as the average particle size. A measurement sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and ultrasonically dispersing for 10 minutes. The measurement sample was measured using a laser diffraction particle size distribution analyzer, with blue and red light source wavelengths used, and the particle size distribution of the inorganic filler on a volume basis was measured using a flow cell system, and the average particle size was calculated as the median diameter from the particle size distribution obtained. An example of a laser diffraction particle size distribution analyzer is the "LA-960" manufactured by Horiba, Ltd.

[0185] The specific surface area of ​​the inorganic filler is not particularly limited, but is preferably 0.1 m 2 / g or more, more preferably 0.5m 2 / g or more, more preferably 1m 2 / g or more, particularly preferably 3m 2 The upper limit of the specific surface area of ​​the inorganic filler is not particularly limited, but is preferably 100 m 2 / g or less, more preferably 50m 2 / g or less, more preferably 30m 2 / g or less, particularly preferably 10m 2 The specific surface area of ​​the inorganic filler is obtained by adsorbing nitrogen gas onto the surface of a sample using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) according to the BET method, and then calculating the specific surface area using the BET multipoint method.

[0186] From the viewpoint of improving moisture resistance and dispersibility, the inorganic filler is preferably treated with a surface treatment agent. Examples of the surface treatment agent include a fluorine-containing silane coupling agent, an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an alkoxysilane, an organosilazane compound, and a titanate coupling agent. The surface treatment agent may be used alone or in any combination of two or more.

[0187] Examples of commercially available surface treatment agents include Shin-Etsu Chemical Co., Ltd.'s "KBM403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM803" (3-mercaptopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent), and Shin-Etsu Chemical Co., Ltd.'s "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane).

[0188] The degree of surface treatment with the surface treatment agent is preferably within a predetermined range from the viewpoint of improving the dispersibility of the inorganic filler. Specifically, 100% by mass of the inorganic filler is preferably surface-treated with 0.2% to 5% by mass of the surface treatment agent, more preferably 0.2% to 3% by mass, and even more preferably 0.3% to 2% by mass.

[0189] The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of ​​the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of ​​the inorganic filler is set to 0.02 mg / m 2 More than 0.1 mg / m is preferable. 2More preferably, 0.2 mg / m or more 2 On the other hand, from the viewpoint of preventing an increase in the melt viscosity of the resin composition or the melt viscosity in the form of a sheet, it is more preferable that the melt viscosity is 1.0 mg / m 2 Preferably less than 0.8 mg / m 2 Less than 0.5 mg / m is more preferable. 2 The following is even more preferred:

[0190] The carbon amount per unit surface area of ​​the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solid content, the carbon amount per unit surface area of ​​the inorganic filler can be measured using a carbon analyzer. The carbon analyzer that can be used is the "EMIA-320V" manufactured by Horiba, Ltd.

[0191] The content of the inorganic filler in the resin composition layer of the resin sheet used in step (1) is preferably 20% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, even more preferably 55% by mass or more, and particularly preferably 60% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition layer. The upper limit of the content of the inorganic filler in the resin composition layer is not particularly limited, but is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, and particularly preferably 75% by mass or less, based on 100% by mass of the nonvolatile components in the resin composition layer.

[0192] In a preferred embodiment, the resin composition layer of the resin sheet used in step (1) may contain a thermoplastic resin. Examples of thermoplastic resins include thermoplastic polyimide resins, polycarbonate resins, phenoxy resins, polyvinyl acetal resins, copolymers, polyamide-imide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyetheretherketone resins, and thermoplastic polyphenylene ether resins. The resin composition layer preferably contains a thermoplastic resin selected from thermoplastic polyimide resins, polycarbonate resins, phenoxy resins, polyvinyl acetal resins, and copolymers, and more preferably a thermoplastic resin selected from phenoxy resins and copolymers. The thermoplastic resins may be used alone or in combination of two or more.

[0193] Specific examples of thermoplastic polyimide resins include "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., and "Rikacoat SN20" and "Rikacoat PN20" manufactured by New Japan Chemical Co., Ltd.

[0194] Examples of polycarbonate resins include hydroxyl group-containing carbonate resins, phenolic hydroxyl group-containing carbonate resins, carboxyl group-containing carbonate resins, acid anhydride group-containing carbonate resins, isocyanate group-containing carbonate resins, and urethane group-containing carbonate resins. Specific examples of polycarbonate resins include "FPC0220" manufactured by Mitsubishi Gas Chemical Company, Inc., "T6002" and "T6001" (polycarbonate diols) manufactured by Asahi Kasei Chemicals Corporation, and "C-1090," "C-2090," and "C-3090" (polycarbonate diols) manufactured by Kuraray Co., Ltd. Specific examples of polyether ether ketone resins include "Sumiploy K" manufactured by Sumitomo Chemical Co., Ltd.

[0195] Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A, bisphenol F, bisphenol S, bisphenolacetophenone, novolac, biphenyl, fluorene, dicyclopentadiene, norbornene, naphthalene, anthracene, adamantane, terpene, and trimethylcyclohexane. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group.

[0196] Specific examples of phenoxy resins include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both of which are phenoxy resins containing a bisphenol A skeleton); "YX8100" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol S skeleton); "YX6954" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol acetophenone skeleton); "FX280" and "FX293" manufactured by Nippon Steel Chemical & Material Co., Ltd.; and "YX7200B35," "YL7500BH30," "YX6954BH30," "YX7553BH30," "YL7769BH30," "YL6794," "YL7213," "YL7290," and "YL7482" manufactured by Mitsubishi Chemical Corporation.

[0197] Examples of polyvinyl acetal resins include polyvinyl formal resins and polyvinyl butyral resins, with polyvinyl butyral resins being preferred. Specific examples of polyvinyl acetal resins include Denka Butyral 4000-2, Denka Butyral 5000-A, Denka Butyral 6000-C, and Denka Butyral 6000-EP, manufactured by Denki Kagaku Kogyo Co., Ltd.; and S-LEC BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, and BM series, manufactured by Sekisui Chemical Co., Ltd.

[0198] The copolymers are copolymers obtained by polymerizing two or more monomers selected from styrene, ethylene, propylene, isoprene, butadiene, acrylate, and methacrylate, or hydrogenated products thereof.

[0199] Examples of copolymers include ethylene copolymer resins such as low-density polyethylene, very low-density polyethylene, high-density polyethylene, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer; and polyolefin polymers such as polypropylene and ethylene-propylene block copolymer.

[0200] Another example of the copolymers is polybutadiene resin, such as hydrogenated polybutadiene skeleton-containing resin, hydroxyl group-containing polybutadiene resin, phenolic hydroxyl group-containing polybutadiene resin, carboxyl group-containing polybutadiene resin, acid anhydride group-containing polybutadiene resin, epoxy group-containing polybutadiene resin, isocyanate group-containing polybutadiene resin, urethane group-containing polybutadiene resin, polyphenylene ether-polybutadiene resin, etc.

[0201] Another example of copolymers is polystyrene resin. The polystyrene resin may be a copolymer containing an optional repeating unit other than the styrene unit in combination with the styrene unit, or may be a hydrogenated polystyrene resin. Examples of polystyrene resins include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-butadiene-butylene-styrene block copolymer (SBBS), styrene-butadiene diblock copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-isoprene block copolymer, hydrogenated styrene-butadiene random copolymer, and styrene-maleic anhydride copolymer. Specific examples of polystyrene resins include hydrogenated styrene-based thermoplastic elastomers "H1041," "Tuftec H1043," "Tuftec P2000," and "Tuftec MP10" (manufactured by Asahi Kasei Corporation); epoxidized styrene-butadiene thermoplastic elastomers "Epofriend AT501" and "CT310" (manufactured by Daicel Corporation); modified styrene-based elastomers having hydroxyl groups "Septon HG252" (manufactured by Kuraray Co., Ltd.); modified styrene-based elastomers having carboxyl groups "Tuftec N503M," modified styrene-based elastomers having amino groups "Tuftec N501," modified styrene-based elastomers having acid anhydride groups "Tuftec M1913" (manufactured by Asahi Kasei Chemicals Corporation); unmodified styrene-based elastomers "Septon S8104" (manufactured by Kuraray Co., Ltd.); and styrene-ethylene / butylene-styrene block copolymers "FG1924" (manufactured by Kraton) and "EF-40" (manufactured by Cray Valley).

[0202] Specific examples of polyamide-imide resins include "Vylomax HR11NN" and "Vylomax HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of polyamide-imide resins also include modified polyamide-imides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamide-imides) manufactured by Hitachi Chemical Co., Ltd.

[0203] A specific example of the polyetherimide resin is "Ultem" manufactured by GE.

[0204] Specific examples of polysulfone resins include polysulfones "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

[0205] A specific example of the polyethersulfone resin is "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

[0206] Specific examples of polyether ether ketone resins include PEEK-150PF and 450PF manufactured by Victrex.

[0207] A specific example of the thermoplastic polyphenylene ether resin is "NORYL SA90" manufactured by SABIC.

[0208] From the viewpoint of further improving film formability, the weight average molecular weight (Mw) of the thermoplastic resin is preferably 5,000 or more, more preferably 8,000 or more, even more preferably 10,000 or more, particularly preferably 20,000 or more, and is preferably 100,000 or less, more preferably 70,000 or less, even more preferably 60,000 or less, particularly preferably 50,000 or less.

[0209] The content of the thermoplastic resin in the resin composition layer of the resin sheet used in step (1) is not particularly limited, but when the non-volatile components in the resin composition layer are taken as 100% by mass, it may be preferably 0.01 to 20% by mass, more preferably 0.05 to 15% by mass, even more preferably 0.1 to 10% by mass, even more preferably 0.3 to 5% by mass, and particularly preferably 0.5 to 2% by mass.

[0210] In a preferred embodiment, the resin composition layer of the resin sheet used in step (1) may contain additives such as a curing accelerator and a radical polymerization initiator.

[0211] The curing accelerator functions as a curing catalyst that accelerates the curing of the thermosetting resin. Examples of the curing accelerator include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, and amine-based curing accelerators. The curing accelerator preferably contains an amine-based curing accelerator or an imidazole-based curing accelerator. One type of curing accelerator may be used alone, or two or more types may be used in combination.

[0212] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-methylimidazole. Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl -(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct , 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, and other imidazole compounds, as well as adducts of imidazole compounds with epoxy resins.

[0213] Examples of the amine-based curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene.

[0214] The radical polymerization initiator is preferably a thermal radical polymerization initiator that can generate radicals by applying thermal energy, such as a peroxide-based polymerization initiator or an azo compound-based polymerization initiator.

[0215] Examples of peroxide polymerization initiators include dialkyl peroxide compounds such as di-t-butyl peroxide, dicumyl peroxide, and t-hexylperoxy-2-ethylhexanoate; diacyl peroxide compounds such as lauroyl peroxide, benzoyl peroxide, benzoyltoluyl peroxide, and toluyl peroxide; perester compounds such as t-butyl peracetate, t-butyl peroxyoctoate, and t-butyl peroxybenzoate; ketone peroxide compounds; peroxycarbonate compounds; and peroxyketal compounds such as 1,1-di(t-amylperoxy)cyclohexane.

[0216] Examples of the azo compound polymerization initiator include azonitrile compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile); azoamide compounds such as 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}; Examples of suitable azoamidine compounds include 2'-azobis(2-amidinopropane) dihydrochloride and 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride; azoalkane compounds such as 2,2'-azobis(2,4,4-trimethylpentane) and 4,4'-azobis(4-cyanopentanoic acid); azo compounds having an oxime skeleton such as 2,2'-azobis(2-methylpropionamidoxime); and 2,2'-azobis(isobutyrate) dimethyl.

[0217] The content of the additive in the resin composition layer of the resin sheet used in step (1) is not particularly limited, but is preferably 0.001 to 5 mass% or less, more preferably 0.001 to 1 mass% or less, even more preferably 0.01 to 0.5 mass%, and particularly preferably 0.02 to 0.2 mass%, assuming that the non-volatile components in the resin composition layer are 100 mass%.

[0218] The resin composition of the present invention may further contain an arbitrary organic solvent as a volatile component in addition to the non-volatile components described above. Any known organic solvent can be used as the organic solvent, and the type is not particularly limited. Examples of the organic solvent include ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether-based solvents such as tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, and anisole; alcohol-based solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; and ether esters such as 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples of suitable organic solvents include ester solvents; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. These organic solvents may be used singly or in combination of two or more in any ratio.

[0219] The resin sheet can be produced, for example, by applying a varnish-like resin composition to a support using a die coater or the like and drying to form a resin composition layer. Drying for producing the resin sheet may be carried out by known methods such as heating or hot air blowing. For example, a resin composition layer can be formed by drying at 50°C to 150°C, preferably 80°C to 120°C, for 1 minute to 60 minutes, preferably 3 minutes to 10 minutes. The content of the organic solvent in the varnish-like resin composition to be applied to a support is not particularly limited, but is, for example, preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and particularly preferably 10% by mass or less, assuming that all components in the resin composition are 100% by mass. [Example]

[0220] The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples. In the following, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Unless otherwise specified, the temperature conditions are room temperature (23°C), and unless otherwise specified, the pressure conditions are atmospheric pressure (1 atm).

[0221] <Production Example 1: Production of Resin Sheet 1> 8 parts of tetramethylbisphenol type epoxy resin (Mitsubishi Chemical Corporation "YX4000H", epoxy equivalent 194g / eq.), 10 parts of biphenyl aralkyl type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000L", epoxy equivalent approximately 271g / eq.), 2 parts of naphthalene type epoxy resin (DIC Corporation "HP6000L", epoxy equivalent approximately 213g / eq.), 2 parts of bifunctional epoxy resin (Nippon Steel Chemical Co., Ltd. "ZX1658GS", epoxy equivalent approximately 133g / eq.), 4 parts of phenolic hardener with triazine skeleton and cresol novolac structure (DIC Corporation "LA-3018-50P", phenol equivalent approximately 151, 2-methoxypropanol solution with 50% solids by mass), 4 parts of activated ester resin (DIC Corporation "H A varnish-like resin composition was prepared by adding 6 parts of "P-C-8151-62T," a phenol equivalent of approximately 238, a toluene solution with a solids content of 62% by weight, 6 parts of a phenoxy resin ("YL7800BH40," manufactured by Mitsubishi Chemical Corporation, a MEK and cyclohexane solution with a solids content of 40% by weight), 2 parts of a phenoxy resin, and 50 parts of silica ("SO-C2," manufactured by Admatechs Co., Ltd., average particle size 0.5 μm, surface treatment amount: 0.6% by weight of amino silane coupling agent per 100% by weight of silica) that had been surface-treated with an amino silane coupling agent ("KBM573," manufactured by Shin-Etsu Chemical Co., Ltd., N-phenyl-3-aminopropyltrimethoxysilane), and 1 part of a curing accelerator ("DMAP-5M," a MEK solution with a solids content of 5% by weight of 1,4-dimethylaminopyridine). Next, the varnish-like resin composition was uniformly applied to a PET film ("AL5" manufactured by Lintec Corporation, thickness 38 μm) using a die coater so that the thickness after drying would be 25 μm, and then dried at 100°C for 5 minutes to produce resin sheet 1.

[0222] <Production Example 1': Production of Resin Sheet 1'> Resin sheet 1' was produced in the same manner as resin sheet 1 in manufacturing example 1, except that the varnish-like resin composition was applied to a carrier-attached copper foil "MT18FL (thin copper foil thickness 3 μm)" manufactured by Mitsui Mining & Smelting Co., Ltd. instead of being applied to a PET film ("AL5" manufactured by Lintec Corporation, thickness 38 μm).

[0223] <Production Example 2: Preparation of Resin Sheet 2> Resin sheet 2 was produced in the same manner as resin sheet 1 in Production Example 1, except that the amount of surface-treated silica added was changed from 50 parts to 40 parts.

[0224] <Production Example 3: Preparation of Resin Sheet 3> Resin sheet 3 was produced in the same manner as resin sheet 1 in Production Example 1, except that the amount of surface-treated silica added was changed from 50 parts to 100 parts.

[0225] <Production Example 4: Preparation of Resin Sheet 4> Resin sheet 4 was produced in the same manner as resin sheet 1 in Production Example 1, except that the amount of surface-treated silica added was changed from 50 parts to 120 parts.

[0226] <Production Example 5: Preparation of Resin Sheet 5> Resin sheet 5 was produced in the same manner as resin sheet 1 in Production Example 1, except that instead of adding both the phenolic curing agent having a triazine skeleton and a cresol novolac structure and the active ester, 20 parts of a cyanate ester ("BA230S" manufactured by Lonza, cyanate ester equivalent 139 g / eq., MEK solution with a solids content of 75 mass %) was added, and the amount of surface-treated silica added was changed from 50 parts to 80 parts.

[0227] <Production Example 6: Preparation of Resin Sheet 6> Polyphenylene ether resin (Mitsubishi Gas Chemical Company, "OPE-2S," vinyl equivalent 590 g / eq., toluene solution with 65% solids by mass), 5 parts maleimide resin (Designer Molecules, "BMI-689," maleimide equivalent 345 g / eq.), 5 parts biphenylaralkyl maleimide resin (Nippon Kayaku Co., Ltd., "MIR-3000-70MT," maleimide equivalent 393 g / eq., MEK and toluene solution with 70% solids by mass), 10 parts liquid acrylate resin (Shin-Nakamura Chemical Co., Ltd., "A-DOG," vinyl group equivalent approximately 163 g / eq.), copolymer A varnish-like resin composition was prepared by mixing 2 parts of a 30 wt% toluene solution of a polymeric elastomer (Asahi Kasei Corporation's "P2000"), 40 parts of silica (Admatechs' "SO-C2", average particle size 0.5 μm, surface treatment amount: 0.6 wt% amino silane coupling agent per 100 wt% silica) that had been surface-treated with an amino silane coupling agent (Shin-Etsu Chemical's "KBM573", N-phenyl-3-aminopropyltrimethoxysilane), and 1 part of a peroxide polymerization initiator (NOF Chemical Corporation's "Perhexyne 25B" toluene solution with a 10 wt% solids content). The varnish-like resin composition was then uniformly applied to a PET film (Lintec Corporation's "AL5", 38 μm thick) using a die coater to a dried thickness of 25 μm, and dried at 100°C for 5 minutes to produce a resin sheet 6.

[0228] Example 1 (Lamination process) The resin sheet 1 obtained in Production Example 1 was superimposed on the resin composition layer surface so that a polyimide film ("Kapton H" manufactured by DuPont-Toray Co., Ltd., thickness 50 μm) was in contact with the surface, and using a vacuum pressure laminator ("MVLP-700" manufactured by Meiki Seisakusho Co., Ltd.), vacuum suction was performed at 120°C for 30 seconds, and then the laminate was laminated on top of the support (PET film) by pressing it together with heat-resistant rubber for 30 seconds under vacuum at 120°C and a pressure of 0.7 MPa.

[0229] (drying process) After lamination, the resin composition layer was dried at 120° C. for 10 minutes without peeling off the support.

[0230] (peeling process) After drying, the support was peeled off from the resin sheet.

[0231] (heat-press bonding process) After peeling off the support, a copper foil with a carrier "MT18FL (thin copper foil thickness 3 μm)" manufactured by Mitsui Mining & Smelting Co., Ltd. was superimposed on the surface of the resin composition layer so that the thin copper foil side was in contact with the resin composition layer. Using a test press device "KVHC" manufactured by Kitagawa Seiki Co., Ltd., the foil was evacuated to 1.0 MPa and heated from 25°C at a rate of 5°C per minute, and then heated and pressed at a temperature of 200°C for 120 minutes to flatten and harden the copper foil with a carrier, thereby laminating it onto the resin composition layer and obtaining an evaluation sample.

[0232] <Example 2> An evaluation sample was obtained in the same manner as in Example 1, except that the drying conditions in the drying step of the resin composition layer were changed from 120° C. for 10 minutes to 120° C. for 30 minutes.

[0233] Example 3 (Lamination process) The resin sheet 1 obtained in Example 1 was superimposed on the resin composition layer surface so that a polyimide film ("Kapton H" manufactured by DuPont-Toray Co., Ltd., thickness 50 μm) was in contact with the surface, and using a vacuum pressure laminator ("MVLP-700" manufactured by Meiki Seisakusho Co., Ltd.), vacuum suction was performed at 120°C for 30 seconds, and then the laminate was laminated on the support (PET film) by pressing it together with heat-resistant rubber for 30 seconds under vacuum at 120°C and a pressure of 0.7 MPa.

[0234] (peeling process) After lamination, the support was peeled off from the resin sheet.

[0235] (drying process) After the support was peeled off, the temperature was raised and the resin composition layer was dried at 120° C. for 10 minutes.

[0236] (heat-press bonding process) After drying, a copper foil with a carrier "MT18FL (thin copper foil thickness 3 μm)" manufactured by Mitsui Mining & Smelting Co., Ltd. was superimposed on the surface of the resin composition layer so that the thin copper foil side was in contact with the resin composition layer, and using a test press device "KVHC" manufactured by Kitagawa Seiki Co., Ltd., the foil was heated under vacuum at 1.0 MPa from 25°C at a rate of 5°C per minute, and then heated and pressed at a temperature of 200°C for 120 minutes to flatten and harden the foil, thereby laminating the copper foil with a carrier on the resin composition layer and obtaining an evaluation sample.

[0237] Example 4 An evaluation sample was obtained in the same manner as in Example 1, except that the resin composition 2 obtained in Production Example 2 was used instead of the resin sheet 1 obtained in Production Example 1.

[0238] <Example 5> An evaluation sample was obtained in the same manner as in Example 1, except that the resin composition 3 obtained in Production Example 3 was used instead of the resin sheet 1 obtained in Production Example 1.

[0239] Example 6 An evaluation sample was obtained in the same manner as in Example 1, except that the resin composition 4 obtained in Production Example 4 was used instead of the resin sheet 1 obtained in Production Example 1.

[0240] Example 7 An evaluation sample was obtained in the same manner as in Example 1, except that the resin composition 5 obtained in Production Example 5 was used instead of the resin sheet 1 obtained in Production Example 1.

[0241] Example 8 An evaluation sample was obtained in the same manner as in Example 1, except that the resin composition 6 obtained in Production Example 6 was used instead of the resin sheet 1 obtained in Production Example 1.

[0242] <Comparative Example 1> (Lamination process) The resin sheet 1' obtained in Manufacturing Example 1' was superimposed on the resin composition layer surface so that a polyimide film ("Kapton H" manufactured by DuPont-Toray Co., Ltd., thickness 50 μm) was in contact with the surface, and using a vacuum pressure laminator ("MVLP-700" manufactured by Meiki Seisakusho Co., Ltd.), vacuum suction was performed at 120°C for 30 seconds, and then the sheet was laminated on top of the support (copper foil with carrier) by pressing it together with heat-resistant rubber for 30 seconds under vacuum at 120°C and a pressure of 0.7 MPa.

[0243] (drying process) After lamination, an attempt was made to dry the resin composition layer at 120° C. for 10 minutes without peeling off the support.

[0244] (heat-press bonding process) After drying, the resin sheet with copper foil laminated to the polyimide film was vacuumed using a test press device "KVHC" manufactured by Kitagawa Seiki Co., Ltd., at 1.0 MPa, and heated from room temperature at 5°C per degree, and then heated and pressed at 200°C for 120 minutes to flatten and harden the resin sheet, thereby obtaining an evaluation sample.

[0245] <Comparative Example 2> The resin sheet 1' obtained in Manufacturing Example 1' was superimposed so that a polyimide film ("Kapton H" manufactured by Toray DuPont Co., Ltd., thickness 50 μm) was in contact with the surface of the resin composition layer, and laminated using a test press device "KVHC" manufactured by Kitagawa Seiki Co., Ltd., under vacuum at 1.0 MPa, with the temperature raised from room temperature by 5°C each time, and heated and pressed at a temperature of 120°C for 30 minutes to obtain an evaluation sample.

[0246] <Comparative Example 3> An evaluation sample was obtained in the same manner as in Example 1, except that the resin composition 2 obtained in Production Example 2 was used instead of the resin sheet 1 obtained in Production Example 1, and the drying process of the resin composition layer was not performed, and the support was peeled off immediately after lamination.

[0247] <Comparative Example 4> An evaluation sample was obtained in the same manner as in Example 1, except that the drying conditions in the drying step of the resin composition layer were 120° C. for 30 minutes.

[0248] <Test Example 1: Measurement of Melt Viscosity> The carrier-attached copper foil and polyimide film were peeled off from the evaluation samples prepared in the Examples and Comparative Examples before the lamination process and before thermocompression bonding to obtain 1.2 g of resin samples. The minimum melt viscosity of the obtained resin samples was measured using a dynamic viscoelasticity measuring device (Rheosol-G3000, manufactured by UBM). Specifically, the dynamic viscoelasticity was measured by heating the samples over a temperature range from a starting temperature of 60°C to 200°C, and the minimum melt viscosity (poise) before the lamination process and before thermocompression bonding was calculated. The minimum melt viscosity before thermocompression bonding was evaluated according to the following criteria. The measurement conditions were a heating rate of 5°C / min, a measurement temperature interval of 2.5°C, a vibration frequency of 1 Hz, and a strain of 1 degree.

[0249] Evaluation criteria: 〇: Minimum melt viscosity is 3500 poise or more and 10000 poise or less △: Minimum melt viscosity is 2000 poise or more and less than 3500 poise, or more than 10000 poise and less than 20000 poise ×: The minimum melt viscosity is less than 2000 poise or greater than 20000 poise

[0250] <Test Example 2: Measurement of resin film thickness after lamination> The polyimide film and carrier copper foil were peeled off from the evaluation samples after thermocompression bonding produced in the Examples and Comparative Examples, and the thicknesses of the resin and thin copper were measured using a high-precision Digimatic Micrometer (MDH-25MB) manufactured by Mitutoyo Corporation. The resin thickness was calculated by subtracting the thin copper thickness of 3 μm, and evaluated based on the following evaluation criteria.

[0251] Evaluation criteria: ○: Resin film thickness is greater than 12 μm (no voids found in visual inspection) △: Resin film thickness is greater than 10 μm and less than 12 μm (no voids in visual inspection) ×: Resin film thickness is 10 μm or less (no voids in visual appearance inspection) ××: Voids found during visual inspection

[0252] <Test Example 3: Measurement of Glass Transition Temperature> The polyimide film and carrier copper foil were peeled off from the evaluation samples prepared in the Examples and Comparative Examples after thermocompression bonding, and the resulting cured products were measured in "tensile mode" using a Seiko Instruments Inc. DMS-6100 thermomechanical analyzer (DMA). The measurement was carried out in the range of 25°C to 240°C with a temperature increase rate of 5°C / min. The glass transition temperature (Tg) was evaluated based on the following evaluation criteria.

[0253] Evaluation criteria: ○: Tg is 150℃ or higher △: Tg is 140℃ or more and less than 150℃ ×: Tg is less than 140°C

[0254] <Test Example 4: Measurement of organic solvent content before heat and pressure bonding> The amount of residual solvent in the resin sheets obtained in the production examples before the lamination step and before the thermocompression bonding step was calculated by drying the resin sheets at 130°C for 15 minutes and measuring the weights before and after drying.

[0255] <Test Example 5: Measurement of adhesion strength to copper foil> The carrier copper foil was peeled from the evaluation samples prepared in the Examples and Comparative Examples after thermocompression bonding, and an electrolytic copper plating process was performed using a chemical solution manufactured by Atotech Japan to achieve a copper thickness of 25 μm. A 10 mm wide and 100 mm long cut was made in the plated conductor layer (second conductor layer), and one end of the cut was peeled off and gripped with a gripper. The load [kgf / cm (N / cm)] when 35 mm was peeled off vertically at a rate of 50 mm / min at room temperature (25°C) was measured. A tensile tester ("AC-50C-SL" manufactured by TSE Corporation) was used for the measurement.

[0256] Evaluation criteria: Void: When a void occurs 〇: Adhesion strength to copper foil is 0.6 kgf / cm or more (no voids) ×: Adhesion strength with copper foil is less than 0.6 kgf / cm (no voids)

[0257] <Test Example 6: Evaluation of resin chipping during cutting> The resin sheets of Examples 1, 4 to 8 and Comparative Example 1 were cut with a roller cutter (558N type) manufactured by DAHLE, and the cut edges were visually inspected for cracks and chips. No resin chipping was observed in the resin sheets of Examples 1 and 4 to 8, but resin chipping was observed in the resin sheets of Comparative Examples 1 and 2.

[0258] The nonvolatile components and amounts used of the resin compositions of Examples 1 to 8 and Comparative Examples 1 to 4, the substrates, production conditions, measurement results of Test Examples 1 to 5, and evaluation results are summarized in Table 1 below.

[0259] [Table 1]

[0260] The results shown in Table 1 above indicate that in a wiring board manufacturing method including the steps of laminating a resin sheet having a resin composition layer on a substrate, peeling off the support, and thermocompression bonding a metal foil to the resin composition layer, when the minimum melt viscosity of the resin composition layer before thermocompression bonding is 2,000 poise to 20,000 poise, changes in the thickness of the insulating layer can be suppressed and good metal foil adhesion and glass transition temperature can be achieved, even after processes including vacuum hot pressing. Furthermore, the results of Test Example 6 also indicate that the occurrence of resin chipping due to cutting of the resin sheet can be suppressed.

Claims

1. (1) A step of heating and laminating a resin sheet having a support and a resin composition layer provided on the support to a substrate so that the resin composition layer of the resin sheet is bonded to the substrate; (2) peeling the support from the resin composition layer; and (3) A step of heating and pressing a metal foil onto a resin composition layer using a vacuum hot press. A method for manufacturing a wiring board, comprising: the resin composition layer contains a thermosetting resin and an inorganic filler; the content of the inorganic filler in the resin composition layer is 40 to 90% by mass, where the non-volatile components in the resin composition layer are 100% by mass; In the step (3), the minimum melt viscosity of the resin composition layer before thermocompression bonding is 2,000 to 20,000 poise when measured in a temperature range of 60°C to 200°C, at a frequency of 1 Hz, and at a strain of 1 degree.

2. 2. The method for producing a wiring board according to claim 1, further comprising the step of drying the resin composition layer (A) as a step carried out after the step (1) and before the step (2), or as a step carried out after the step (2) and before the step (3).

3. 2. The method for producing a wiring board according to claim 1, wherein the minimum melt viscosity of the resin composition layer before lamination in step (1) is lower than the minimum melt viscosity of the resin composition before heat-pressure bonding in step (3).

4. 2. The method for producing a wiring board according to claim 1, wherein the heating temperature during lamination in step (1) is 80 to 140°C.

5. 2. The method for producing a wiring board according to claim 1, wherein the heating temperature during thermocompression bonding in step (3) is 170 to 230°C.

6. 2. The method for producing a wiring board according to claim 1, wherein the pressure conditions during the thermocompression bonding in the step (3) are 0.5 to 2.0 MPa.

7. The method for producing a wiring board according to claim 1, wherein the thickness of the resin composition layer before lamination in step (1) is 40 μm or less.

8. The method for producing a wiring board according to claim 1, wherein the resin composition layer after the heat-pressure bonding in the step (3) has a glass transition temperature of 140°C or higher.

9. The method for producing a wiring board according to claim 1, wherein the thickness of the resin composition layer after the thermocompression bonding in the step (3) is more than 10 μm.

10. 2. The method for producing a wiring board according to claim 1, wherein a thickness reduction rate of the resin composition layer after the heat-pressure bonding in the step (3) relative to the resin composition layer before lamination in the step (1) is 40% or less.

11. The content of the organic solvent in the resin composition layer before heat and pressure bonding in the step (3) is 0.3 to 2.5% by mass, when all components in the resin composition layer are 100% by mass. The method for producing a wiring board according to claim 1.

12. The method for producing a wiring board according to claim 1 , wherein the support is a plastic film.

13. (4) A process of forming a circuit pattern from metal foil by a subtractive method The method for manufacturing a wiring board according to claim 1 , comprising:

14. (4') A process of forming a circuit pattern from a metal foil by a modified semi-additive method The method for manufacturing a wiring board according to claim 1 , comprising:

15. 2. The method for producing a wiring board according to claim 1, wherein the thermosetting resin comprises a thermosetting resin selected from the group consisting of epoxy resin, cyanate ester resin, maleimide resin, and thermosetting modified polyphenylene ether resin.

16. 2. The method for producing a wiring board according to claim 1, wherein the content of the inorganic filler in the resin composition layer is 40 to 75% by mass, where the non-volatile components in the resin composition layer are 100% by mass.

17. The method for producing a wiring board according to claim 1 , wherein the resin composition layer contains a thermoplastic resin.

18. 18. The method for producing a wiring board according to claim 17, wherein the thermoplastic resin comprises a thermoplastic resin selected from thermoplastic polyimide resin, polycarbonate resin, phenoxy resin, polyvinyl acetal resin, and copolymers.

19. The method for producing a wiring board according to claim 18, wherein the copolymer is a copolymer obtained by polymerizing two or more monomers selected from styrene, ethylene, propylene, isoprene, butadiene, acrylate, and methacrylate, or a hydrogenated product thereof.

20. The method for producing a wiring board according to claim 17, wherein the thermoplastic resin has a weight average molecular weight of 5,000 to 100,000.

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