Method for manufacturing a circuit board and resin sheet used therein

Abstract

The present invention provides a method for manufacturing a circuit board and a resin sheet used therein, which can suppress the generation of interfacial voids and suppress the increase in the surface potential of the support, even when using a large-area substrate. [Solution] A method for manufacturing a circuit board includes a step of laminating a resin sheet, which comprises (X) a support having first and second surfaces and a resin composition layer provided on the second surface of the support, onto a substrate such that the resin composition layer is bonded to the substrate, and satisfies the following conditions (i), (ii-1) and (ii-2). (i) Reduce the atmospheric pressure at the same time as or before the bonding of the resin composition layer and the substrate. (ii-1) The total specific surface area of ​​the inorganic filler in the resin composition layer is 1.5 m² 2 / g or more (calculated on non-volatile components) (ii-2) The surface resistivity of the first surface of the support is 1.0 × 10 10 It is less than or equal to Ω / sq.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a circuit board and a resin sheet used therein. [Background technology]

[0002] In the manufacturing of circuit boards such as wafer-level packages (WLP) and panel-level packages (PLP), the redistribution layer is generally formed by applying a curable resin material to a substrate such as a wafer or panel substrate using a spin-coating method, curing it to form an insulating layer, then forming a conductive layer, and repeating this process to create a multilayer structure (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-87986 [Overview of the project] [Problems that the invention aims to solve]

[0004] As electronic devices become more sophisticated, semiconductor package circuit boards require even finer wiring, and to achieve this, it is necessary to form an insulating layer with good surface flatness. Furthermore, the insulating layer of the circuit board is required to have various properties, such as excellent dielectric properties to suppress transmission loss when operating in high-frequency environments, and the ability to suppress warping when forming large-area insulating layers in the manufacturing of WLP and PLP. Moreover, these requirements are expected to become even more stringent in the future.

[0005] The inventors attempted to use insulating materials in the form of resin sheets in order to achieve high functionality of insulating layers, such as good dielectric properties and low warpage, and to provide insulating layers with good surface flatness. Specifically, they investigated a technique for forming an insulating layer by laminating a resin composition layer on a substrate such as a wafer and curing it, using a resin sheet on which a resin composition layer is provided on a support. As a result, they confirmed that when the surface area of ​​the substrate is large, voids (hereinafter also referred to as "interface voids") tend to occur at the interface between the resin composition layer and the substrate, which can cause blistering or cracking of the insulating layer during curing, making it impossible to manufacture the desired circuit board.

[0006] As a result of investigating a technique that can suppress the generation of interfacial voids even when applying insulating material in the form of a resin sheet to a large-area substrate, the following was found: (a) the atmospheric pressure is reduced at the same time as or before the bonding of the resin composition layer and the substrate, and (b) the total specific surface area of ​​the inorganic filler in the resin composition layer is 1.5 m². 2 We found that the generation of interfacial voids can be suppressed by adjusting the dimensions and content of the inorganic filler so that the value is 1 / g or more (calculated on non-volatile components).

[0007] On the other hand, while employing the techniques described in (a) and (b) above can suppress the generation of interfacial voids, we found that the surface potential of the support increases to a degree that raises concerns about damage to the semiconductor chip, especially when the substrate area is large. This increase in surface potential tended to be more pronounced in resin composition layers aimed at further reducing dielectric loss tangent and warpage.

[0008] The object of the present invention is to provide a method for manufacturing a circuit board and a resin sheet used therein that can suppress the increase in the surface potential of a support while suppressing the generation of interfacial voids, even when using a large-area substrate. [Means for solving the problem]

[0009] As a result of diligent research, the inventors of the present invention have found that the above problems can be solved by a method for manufacturing a circuit board and a resin sheet having the following configuration, and have completed the present invention.

[0010] In other words, the present invention includes the following: [1] (X) A process of laminating a resin sheet, which includes a support having first and second surfaces and a resin composition layer provided on the second surface of the support, onto a substrate such that the resin composition layer is bonded to the substrate. Includes, A method for manufacturing a circuit board that satisfies the following conditions (i), (ii-1), and (ii-2). (i) Reduce the atmospheric pressure at the same time as or before the bonding of the resin composition layer and the substrate. (ii-1) The total specific surface area of ​​the inorganic filler in the resin composition layer is 1.5 m² 2 / g or more (calculated on non-volatile components) (ii-2) The surface resistivity of the first surface of the support is 1.0 × 10 10 It is less than or equal to Ω / sq. [2] The method according to [1], wherein the substrate is (a) a semiconductor wafer having an electrode pad surface, (b) a carrier substrate on which a plurality of semiconductor chips, which are made by framing the semiconductor wafer of (a), are arranged spaced apart from each other so that their electrode pad surfaces are exposed, (c) a substrate on which a sealing resin for sealing semiconductor chips is further provided for the carrier substrate of (b), (d) a substrate on which a redistribution layer is further provided for the sealing resin of the substrate of (c), (e) a carrier substrate on which a plurality of semiconductor chips, which are made by framing the semiconductor wafer of (a), are arranged spaced apart from each other so that their electrode pad surfaces face the carrier substrate, (f) a semiconductor chip encapsulation substrate on which an electrode pad surface is exposed, obtained by further providing a sealing resin for sealing semiconductor chips on the carrier substrate of (e) and then peeling off the carrier substrate, and (g) a substrate on which a redistribution layer is further provided on the electrode pad surface side of the semiconductor chip encapsulation substrate of (f). [3] The method according to [1], wherein the substrate is a substrate with a release layer. [4] The method according to any of [1] to [3], wherein the main surface dimension (minimum dimension) of the base material is 150 mm or more. [5] After step (X), (1) A step of curing the resin composition layer to form an insulating layer, (2) A process of drilling holes in the insulating layer, (3) A step of desmearing the insulating layer, (4) Step of forming a conductive layer on the surface of the insulating layer A method according to any one of [1] to [4], comprising one or more steps selected from the following. [6] The method according to any one of [1] to [5], wherein the resin composition layer includes a stress-relieving material. [7] The method according to any one of [1] to [6], wherein the circuit board is a wafer-level package or a panel-level package. [8] The process includes laminating a resin sheet containing a resin composition layer onto a substrate such that the resin composition layer is bonded to the substrate, provided that the following conditions (i): (i) Reduce the atmospheric pressure at the same time as or before the bonding of the resin composition layer and the substrate. A resin sheet used in the manufacturing method of a circuit board, which satisfies the following conditions: The support comprises a support having first and second surfaces and a resin composition layer provided on the second surface of the support. (ii-1) The total specific surface area of ​​the inorganic filler in the resin composition layer is 1.5 m² 2 It is 1 / g or more (calculated on non-volatile components), (ii-2) The surface resistivity of the first surface of the support is 1.0 × 10 10 A resin sheet with a density of Ω / sq. or less. [9] The resin sheet described in [8], wherein the main surface dimensions (minimum dimensions) of the base material are 150 mm or more.

[10] The total specific surface area of ​​the inorganic filler in the resin composition layer is 4.0 m² 2 A resin sheet as described in [8] or [9], having a value of / g or more (calculated on non-volatile components).

[11] The surface resistivity of the second surface of the support is 1.0 × 10⁻⁶ 10 A resin sheet described in any of [8] to

[10] , having a density of Ω / sq. or less.

[12] A resin sheet according to any one of [8] to

[11] , wherein the resin composition layer includes a stress-relaxing material.

[13] A resin sheet according to any one of [8] to

[12] , wherein the melt viscosity of the resin composition layer at 100°C is 50,000 poise or less. [Effects of the Invention]

[0011] According to the present invention, even when using a large-area substrate, it is possible to provide a method for manufacturing a circuit board that can suppress the generation of interfacial voids while suppressing an increase in the surface potential of the support, and a resin sheet used therefor.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, the present invention will be described in detail in accordance with its preferred embodiments. However, the present invention is not limited to the following embodiments and examples, and can be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and its equivalent scope.

[0013] [Method for Manufacturing a Circuit Board] The method for manufacturing a circuit board of the present invention (hereinafter, also simply referred to as "the manufacturing method of the present invention") is (X) A step of laminating a resin sheet including a support having first and second surfaces and a resin composition layer provided on the second surface of the support on a substrate such that the resin composition layer is joined to the substrate including characterized by satisfying the following conditions (i), (ii-1), and (ii-2). (i) Reducing the atmospheric pressure simultaneously with or prior to the joining of the resin composition layer and the substrate (ii-1) The total specific surface area of the inorganic filler in the resin composition layer is 1.5 m 2 / g or more (in terms of non-volatile components) (ii-2) The surface resistivity of the first surface of the support is 1.0 × 10 10 Ω / sq. or less

[0014] As mentioned above, the insulating layer of a circuit board requires various properties, such as excellent dielectric properties to suppress transmission loss when operating in a high-frequency environment, and the ability to suppress warping when forming a large-area insulating layer in the manufacturing of WLP and PLP. Furthermore, these requirements are expected to become increasingly stringent in the future. To meet these requirements, an approach from the compositional side of the insulating material can be considered. However, with conventional ink-type or granular insulating materials, it can be difficult to adequately adjust the applicability and melt-flowability when applied to the substrate while meeting the above requirements, and there have been limitations in forming an insulating layer with good surface flatness to realize further fine wiring of circuit boards.

[0015] The inventors have attempted to use insulating materials in the form of resin sheets in order to provide an insulating layer that highly satisfies the characteristics required for the insulating layer of a circuit board and has good surface flatness. In this regard, regarding insulating materials in the form of resin sheets, it has been found that when applied to a large area substrate, interfacial voids occur, and it may not be possible to manufacture the desired circuit board. The occurrence of these interfacial voids can be improved in terms of equipment / process and insulating material composition, namely, (a) reducing the atmospheric pressure at the same time as or before the bonding of the resin composition layer and the substrate, and (b) the total specific surface area of ​​the inorganic filler in the resin composition layer should be 1.5 m². 2 We found that this can be suppressed by adjusting the dimensions and content of the inorganic filler so that it is greater than or equal to / g (calculated in terms of non-volatile components). On the other hand, we found that when the above techniques (a) and (b) are adopted, a new problem arises in which the surface potential of the support rises to a degree that raises concerns about damage to the semiconductor chip, especially when the surface area of ​​the substrate is large. Furthermore, we found that this problem of increased surface potential tends to be more pronounced in resin composition layers aimed at further reducing dielectric loss tangent and warpage.

[0016] In contrast, the manufacturing method of the present invention, which satisfies all of the above specific conditions (i), (ii-1), and (ii-2), can suppress the generation of interfacial voids and suppress the increase in the surface potential of the support, even when the insulating material in the form of a resin sheet is applied to a large-area substrate. Combined with the inherent advantage of using insulating material in the form of a resin sheet, which makes it easy to form an insulating layer with good surface flatness even when compositional improvements are made to highly satisfy the characteristics required for the insulating layer of a circuit board, the manufacturing method of the present invention significantly contributes to achieving further miniaturization of wiring while highly satisfying the characteristics required for the insulating layer of a circuit board.

[0017] <Process (X)> The method for manufacturing a circuit board of the present invention is: (X) A process of laminating a resin sheet, which includes a support having first and second surfaces and a resin composition layer provided on the second surface of the support, onto a substrate such that the resin composition layer is bonded to the substrate. Includes.

[0018] The "substrate" used in process (X) is a circuit board chip 1st (Chip-1 stWhen manufacturing using the ) method, a semiconductor wafer equipped with a circuit element having a predetermined function and an electrode pad surface on which multiple electrode pads electrically connected to this circuit element are formed may be used. Silicon (Si) wafers are preferred as semiconductor wafers, but are not limited to them, and wafers such as gallium arsenide (GaAs), indium phosphide (InP), gallium phosphide (GaP), gallium nitride (GaN), gallium tellurium (GaTe), zinc selenium (ZnSe), and silicon carbide (SiC) wafers may also be used. The chip 1st method is a method in which a semiconductor chip is first provided and a redistribution layer is formed on its electrode pad surface (for example, Japanese Patent Publication No. 2002-289731, Japanese Patent Publication No. 2006-173345, etc.). In such a chip-first manufacturing method, especially when manufacturing a fan-out package, first the semiconductor wafer is divided into individual pieces, each semiconductor chip is placed on a carrier substrate spaced apart from each other, then sealed with resin, and a redistribution layer is formed on the exposed electrode pad surface and the surrounding sealing resin layer (for example, Japanese Patent Publication No. 2012-15191, Japanese Patent Publication No. 2015-126123, etc.). As the carrier substrate, a known substrate used when manufacturing a fan-out package may be used, and the type is not particularly limited, but examples include glass substrates, metal substrates, plastic substrates, etc. In such an embodiment, the "substrate" referred to in process (X) may be a substrate in which the divided semiconductor chips are sealed with sealing resin around them so that their electrode pad surfaces are exposed. For example, a carrier substrate may be used in which a plurality of semiconductor chips, formed by dividing a semiconductor wafer into individual pieces, are placed on it spaced apart from each other so that their electrode pad surfaces are exposed, and a sealing resin for sealing the semiconductor chips is further provided on the carrier substrate. As described below, the method for manufacturing a circuit board of the present invention is widely applicable to the manufacture of a circuit board that includes a step of laminating a resin sheet onto a substrate, and can be applied not only to the case of forming a redistribution layer (or insulating layer thereof) as described above, but also to the case of forming a sealing layer or a solder resist layer.For example, when forming a sealing layer in a fan-out structure package manufactured using the chip-first method, the "substrate" in process (X) can be a carrier substrate in which multiple semiconductor chips, each made by separating a semiconductor wafer, are placed spaced apart from one another. As will be described later, the manufacturing method of the circuit board can be classified into face-up type and face-down type from the viewpoint of the chip mounting direction. In the face-up type, the semiconductor chips should be arranged so that the electrode pad surface is exposed, while in the face-down type, the semiconductor chips should be arranged so that the electrode pad surface faces the carrier substrate. Furthermore, when forming the solder resist layer, process (X) should be performed to form the protective layer after forming the redistribution layer (the manufacturing procedure including the formation of the conductor layer will be described later).

[0019] Therefore, in one embodiment, the substrate is (a) a semiconductor wafer having an electrode pad surface, (b) a carrier substrate on which a plurality of semiconductor chips, formed by framing the semiconductor wafer of (a), are arranged spaced apart from each other so that their electrode pad surfaces are exposed, (c) a substrate on which a sealing resin for sealing semiconductor chips is further provided on the carrier substrate of (b), (d) a substrate on which a redistribution layer is further provided on the sealing resin of the substrate of (c), (e) a carrier substrate on which a plurality of semiconductor chips, formed by framing the semiconductor wafer of (a), are arranged spaced apart from each other so that their electrode pad surfaces face the carrier substrate, (f) a semiconductor chip encapsulation substrate with an exposed electrode pad surface, obtained by further providing a sealing resin for sealing semiconductor chips on the carrier substrate of (e) and then peeling off the carrier substrate, and (g) a substrate on which a redistribution layer is further provided on the electrode pad surface side of the semiconductor chip encapsulation substrate of (f). Here, (a) corresponds to the case where a redistribution layer (insulating layer) is formed when manufacturing a fan-in package, (c) and (f) correspond to the case where a redistribution layer (insulating layer) is formed when manufacturing a fan-out package, (b) and (e) correspond to the case where a sealing layer is formed, and (d) and (g) correspond to the case where a solder resist layer is formed. Furthermore, (b) to (d) correspond to the case where a face-up type manufacturing method is adopted, and (e) to (g) correspond to the case where a face-down type manufacturing method is adopted.

[0020] Also, the circuit board is redistributed in the 1st layer (RDL-1 st When manufacturing using the ) method, the "substrate" used in process (X) may be a substrate with a release layer. The redistribution layer 1st method is a method in which a redistribution layer is first provided, and a semiconductor chip is provided on the redistribution layer in such a state that its electrode pad surface can be electrically connected to the redistribution layer (for example, Japanese Patent Publication No. 2015-35551, Japanese Patent Publication No. 2015-170767, etc.). In the redistribution layer 1st method, after the semiconductor chip is provided on the redistribution layer, the redistribution layer is exposed by peeling off the substrate with a release layer. Such a redistribution layer 1st method is particularly suitable when manufacturing a fan-out structure package. As the substrate with a release layer, a known substrate used when manufacturing a circuit board with the redistribution layer 1st method may be used, and the type is not particularly limited, but examples include a glass substrate with a release layer, a metal substrate with a release layer, a plastic substrate with a release layer, etc.

[0021] Therefore, in one embodiment, the substrate is a substrate with a release layer.

[0022] The dimensions of the substrate are not particularly limited and may be determined according to the intended package design. Regarding the dimensions in the direction parallel to the main surface of the substrate (dimensions in the XY direction; also simply referred to as "main surface dimensions"), in the case of a circular or substantially circular substrate (hereinafter simply referred to as "circular substrate"), its diameter may be, for example, 100 mm (4 inches) or more, or 125 mm (5 inches) or more. According to the manufacturing method of the present invention, it is possible to use a larger area substrate while suppressing the generation of interfacial voids and the increase in the surface potential of the support. For example, the diameter of a circular substrate may be 150 mm (6 inches) or more, 200 mm (8 inches) or more, 300 mm (12 inches) or more, or 450 mm (18 inches) or more. The upper limit of the diameter of a circular substrate is not particularly limited and may be, for example, 600 mm (24 inches) or less. Furthermore, in the case of a rectangular or nearly rectangular substrate (hereinafter also referred to as "rectangular substrate"), its main surface dimensions (in the case of a rectangle, the dimensions of its shorter side) can be, for example, 50 mm or more, 75 mm or more, 100 mm or more, or 125 mm or more. According to the manufacturing method of the present invention, even when using a rectangular substrate, it is possible to use a substrate with an even larger surface area while suppressing the generation of interfacial voids and the increase in the surface potential of the support. For example, the main surface dimensions of a rectangular substrate (in the case of a rectangle, the dimensions of its shorter side) can be 150 mm or more, 200 mm or more, 300 mm or more, or 450 mm or more. The upper limit of the main surface dimensions of a rectangular substrate is not particularly limited and can be, for example, 1000 mm or less.

[0023] Therefore, in one embodiment, the main surface dimension (minimum dimension) of the substrate is 150 mm or more. Note that "main surface dimension (minimum dimension)" for the substrate refers to the diameter in the case of a circular substrate, and the dimension of the shorter side of the main surface in the case of a rectangular substrate.

[0024] As mentioned above, the manufacturing method of the present invention allows for the use of a large-area substrate while suppressing the generation of interfacial voids and the increase in the surface potential of the support. For example, the area of ​​the substrate (projected area when viewed from a direction perpendicular to the main surface of the substrate) is 150 cm². 2 More than 200cm 2 More than 300cm 2 More than 500cm 2 More than 700cm 2 More than 1000cm 2More than 1500cm 2 The above may be the case. The upper limit of the surface area of ​​the base material is not particularly limited, for example, 10,000 cm². 2 Below, 8000cm 2 The following are possible options:

[0025] In step (X), a resin sheet (details of which will be described later) is laminated onto the substrate such that the resin composition layer of the resin sheet is bonded to the substrate.

[0026] In the manufacturing method of the present invention, the atmospheric pressure is reduced at the same time as or before the bonding of the resin composition layer and the substrate ("condition (i)"). By performing step (X) in combination with condition (ii-1) described later for the resin sheet, condition (i) can be satisfied, thereby suppressing the generation of interfacial voids even when using a large-area substrate.

[0027] Process (X) may be carried out using any lamination apparatus, provided that such condition (i) can be achieved. For example, lamination apparatuses (sheet bonding apparatuses) described in Japanese Patent Publication No. 2013-229515, Japanese Patent Publication No. 2006-310338, etc., may be used.

[0028] From the viewpoint of suitably suppressing interfacial voids in combination with the conditions (ii-1) described later, the atmospheric pressure (atmospheric pressure in the chamber where the resin sheet to be processed and the substrate are stored) is preferably reduced to 200 hPa or less, more preferably to 150 hPa or less, and even more preferably to 100 hPa or less, 80 hPa or less, 60 hPa or less, 50 hPa or less, 40 hPa or less, or 30 hPa or less. The atmospheric pressure may be reduced at the same time that the resin composition layer and the substrate are bonded, thereby achieving the above atmospheric pressure, or the atmospheric pressure may be reduced before the resin composition layer and the substrate are bonded, and then the resin composition layer and the substrate are bonded.

[0029] In step (X), the lamination of the resin sheet and the substrate is preferably carried out under heated conditions. The heating temperature when laminating the resin sheet onto the substrate is preferably 60°C or higher, more preferably 80°C or higher or 90°C or higher, and the upper limit of the heating temperature is preferably 150°C or lower, more preferably 140°C or lower or 120°C or lower.

[0030] In step (X), the pressure (compression pressure) when laminating the resin sheet and the substrate is preferably 0.098 MPa or more, more preferably 0.29 MPa or more, and the upper limit of the compression pressure is preferably 1.77 MPa or less, more preferably 1.47 MPa or less.

[0031] In step (X), the time (pressure time) for laminating the resin sheet and the substrate is preferably 20 seconds or more, more preferably 30 seconds or more, and the upper limit of the pressure time is preferably 400 seconds or less, more preferably 300 seconds or less.

[0032] The member used to press the resin sheet and the substrate together (hereinafter also referred to as the "pressing member") may be appropriately determined according to the configuration of the lamination apparatus, but examples include elastic materials such as rubber, metal plates, etc.

[0033] <Other processes> In the manufacturing method of the present invention, any conventionally known steps for manufacturing a desired circuit board may be further included, as long as the resin sheet satisfies the conditions (ii-1) and (ii-2) described later and step (X) is carried out in such a way that the above condition (i) is achieved.

[0034] The following is an example of other steps that may be further included in the manufacturing method of the present invention.

[0035] In one embodiment, the manufacturing method of the present invention is performed after step (X) above, (1) A step of curing the resin composition layer to form an insulating layer, (2) A process of drilling holes in the insulating layer, (3) A step of desmearing the insulating layer, (4) Step of forming a conductive layer on the surface of the insulating layer The process includes one or more steps selected from the following. For example, if step (X) is a step of forming a redistribution layer (or an insulating layer), then steps (1) to (4) may all be performed after step (X). If step (X) is a step of forming a sealing layer or a solder resist layer, then only step (1) needs to be performed after step (X).

[0036] -Process (1)- In step (1), the resin composition layer is cured to form an insulating layer.

[0037] The curing conditions for the resin composition layer are not particularly limited, and conditions commonly used when forming an insulating layer on a circuit board may be used.

[0038] For example, the curing conditions for the resin composition layer vary depending on the type of resin composition, but in one embodiment, the curing temperature is preferably 120°C to 250°C, more preferably 150°C to 240°C, and even more preferably 180°C to 230°C. The curing time can be preferably 5 minutes to 240 minutes, more preferably 10 minutes to 150 minutes, and even more preferably 15 minutes to 120 minutes.

[0039] Before curing the resin composition layer, the resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to curing the resin composition layer, the resin composition layer may be preheated at a temperature of 50°C to 120°C, preferably 60°C to 115°C, more preferably 70°C to 110°C for 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes. Preheating is advantageous because it makes it easier to achieve an insulating layer with low surface roughness after desmearing.

[0040] -Process (2)- In step (2), the insulating layer is drilled.

[0041] This allows for the formation of conductive holes, such as via holes, in the insulating layer. Step (2) may be carried out using, for example, a drill, laser, plasma, etc., depending on the composition of the resin composition used to form the insulating layer. The dimensions and shape of the holes may be determined as appropriate according to the design of the circuit board.

[0042] -Process (3)- In step (3), the insulating layer is desmeared.

[0043] This makes it possible to remove the smear generated inside the via hole by the drilling process. The desmear treatment is not particularly limited and can be carried out by various known methods. In one embodiment, the desmear treatment may be dry desmear treatment, wet desmear treatment, or a combination thereof.

[0044] Examples of dry desmear treatment include plasma-based desmear treatment. Plasma-based desmear treatment removes smear generated in via holes by treating the insulating layer with plasma generated by introducing gas into a plasma generator. There are no particular restrictions on the method of generating the plasma, and examples include microwave plasma generated by microwaves, radio frequency plasma generated by radio frequency, atmospheric pressure plasma generated under atmospheric pressure, and vacuum plasma generated under vacuum, with vacuum plasma generated under vacuum being preferred. Furthermore, the plasma used in desmear treatment is preferably RF plasma excited by radio frequency.

[0045] The gas used for plasma generation is not particularly limited as long as it can remove smear in the via holes, and for example, a gas containing SF6 may be used. In this case, the plasma generation gas may contain other gases in addition to SF6, such as Ar and O2. Among these, a mixed gas containing SF6 and at least one of Ar and O2 is preferred as the plasma generation gas, and a mixed gas containing SF6, Ar and O2 is more preferred, as it facilitates the realization of an insulating layer with low surface roughness after desmearing.

[0046] When using a mixed gas of SF6 and other gases, the mixing ratio (SF6 / other gas: unit is sccm) is preferably 1 / 0.01 to 1 / 1, more preferably 1 / 0.05 to 1 / 1, and even more preferably 1 / 0.1 to 1 / 1, from the viewpoint of easily achieving an insulating layer with low surface roughness after desmearing.

[0047] The duration of the desmear treatment using plasma is not particularly limited, but is preferably 30 seconds or more, more preferably 60 seconds or more, 90 seconds or more, or 120 seconds or more. The upper limit of the desmear treatment duration is preferably 10 minutes or less, and more preferably 5 minutes or less, from the viewpoint of easily achieving an insulating layer with low surface roughness after the desmear treatment.

[0048] Desmearing using plasma can be performed using commercially available plasma desmearing equipment. Among commercially available plasma desmearing equipment, examples suitable for circuit board manufacturing include plasma dry etching equipment from Oxford Instruments, microwave plasma equipment from Nissin, and atmospheric pressure plasma etching equipment from Sekisui Chemical Co., Ltd.

[0049] Alternatively, dry sandblasting can be used as a dry desmear treatment, in which an abrasive material is sprayed from a nozzle to polish the object to be treated. Dry sandblasting can be carried out using commercially available dry sandblasting equipment. When a water-soluble abrasive material is used, rinsing with water after dry sandblasting will prevent the abrasive material from remaining inside the via hole, and the smear can be effectively removed.

[0050] Regardless of the composition of the resin composition layer, dry desmear treatment is preferred from the viewpoint of easily achieving an insulating layer with low surface roughness, and among these, desmear treatment using plasma is more preferred. Therefore, in a preferred embodiment, the insulating layer is subjected to dry desmear treatment, and particularly preferably, the insulating layer is subjected to desmear treatment using plasma.

[0051] Examples of wet desmear treatments include desmear treatment using an oxidizing agent solution. When desmear treatment is performed using an oxidizing agent solution, it is preferable to perform swelling treatment with a swelling solution, oxidation treatment with an oxidizing agent solution, and neutralization treatment with a neutralizing solution in this order. Examples of swelling solutions include "Swelling Dip Securiganth P" and "Swelling Dip Securiganth SBU" manufactured by Attec Japan Co., Ltd. The swelling treatment is preferably performed by immersing the substrate with via holes in a swelling solution heated to 60°C to 80°C for 5 to 10 minutes. As the oxidizing agent solution, an alkaline permanganate aqueous solution is preferred, for example, a solution obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The oxidation treatment with an oxidizing agent solution is preferably carried out by immersing the substrate after swelling treatment in an oxidizing agent solution heated to 60°C to 80°C for 10 to 30 minutes. Examples of commercially available alkaline permanganate aqueous solutions include "Concentrate Compact P", "Concentrate Compact CP", and "Dozing Solution Securigans P" manufactured by Attec Japan Co., Ltd. The neutralization treatment with a neutralizing solution is preferably carried out by immersing the substrate after oxidation treatment in a neutralizing solution heated to 30°C to 50°C for 3 to 10 minutes. An acidic aqueous solution is preferred as the neutralizing solution, and an example of a commercially available product is "Reduction Solution Securigans P" manufactured by Attec Japan Co., Ltd.

[0052] As a wet desmear treatment, a wet sandblasting treatment may also be used, in which an abrasive material and a dispersion medium are sprayed from a nozzle to polish the object to be treated. Wet sandblasting can be carried out using commercially available wet sandblasting equipment.

[0053] In one preferred embodiment, the insulating layer is subjected to a wet desmear treatment, and more preferably, the insulating layer is subjected to a desmear treatment using an oxidizing agent solution.

[0054] When combining dry desmearing and wet desmearing, the dry desmearing may be performed first, or the wet desmearing may be performed first.

[0055] The resin sheet support may be removed before step (4), between step (X) and step (1), between step (1) and step (2), between step (2) and step (3), or after step (3). From the viewpoint of easily achieving an insulating layer with low surface roughness after desmear treatment, it is preferable to remove the support after step (2), and more preferable to remove it after step (3).

[0056] -Process (4)- In step (4), a conductive layer is formed on the surface of the insulating layer.

[0057] In one embodiment, the conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer using conventionally known techniques such as the semi-additive method or the fully additive method. From the viewpoint of ease of manufacture, it is preferable to form it by the semi-additive method. An example of forming the conductor layer by the semi-additive method is shown below.

[0058] First, a plating seed layer is formed on the surface of the insulating layer by electroless plating. The plating seed layer includes at least a conductive seed layer. The conductive seed layer is a layer that functions as an electrode in the electroplating method. The conductive material constituting the conductive seed layer is not particularly limited as long as it exhibits sufficient conductivity, but preferred examples include copper, palladium, gold, platinum, silver, aluminum, and their alloys. The plating seed layer may also include a diffusion barrier layer. The diffusion barrier layer is a layer that prevents the conductive material constituting the conductive seed layer from diffusing into the insulating layer and causing dielectric breakdown. The material constituting the diffusion barrier layer is not particularly limited as long as it can suppress and prevent the diffusion of the conductive material constituting the conductive seed layer, but preferred examples include titanium, tungsten, tantalum, and their alloys. After forming a conductive layer on the plating seed layer in a desired pattern, any unnecessary parts other than the conductive layer formation area are removed by etching or the like. At this time, the smaller the thickness of the plating seed layer, the easier it is to remove the unnecessary parts of the plating seed layer, and the less erosion of the conductive pattern when removing the unnecessary parts, which is advantageous for realizing fine wiring. The thickness of the plated seed layer is preferably 1000 nm (1 μm) or less, more preferably 800 nm or less, 600 nm or less, 500 nm or less, 400 nm or less, or 300 nm or less. In the manufacturing method of the present invention, an insulating layer with good surface flatness can be realized, so the thickness of the plated seed layer may be even thinner. For example, the thickness of the plated seed layer may be 250 nm or less, 200 nm or less, 150 nm or less, 140 nm or less, 120 nm or less, or 100 nm or less. When the plated seed layer includes a diffusion barrier layer, the "thickness of the plated seed layer" in the present invention refers to the average thickness of the entire plated seed layer, including not only the conductive seed layer but also the diffusion barrier layer. When the plated seed layer includes a diffusion barrier layer, the thickness of the diffusion barrier layer is not particularly limited as long as it can suppress and prevent the diffusion of the conductive material constituting the conductive seed layer, but from the viewpoint of contributing to fine wiring, it is preferably 20 nm or less, more preferably 15 nm or less, and even more preferably 10 nm or less. The lower limit of the diffusion barrier layer thickness is not particularly limited and can be, for example, 1 nm or more, 3 nm or more, 5 nm or more, etc.In this case, the remainder of the plating seed layer is preferably a conductive seed layer, and the thickness of the conductive seed layer may be determined in relation to the thickness of the diffusion barrier layer such that the total thickness of the plating seed layer falls within the above-mentioned preferred range.

[0059] The plating seed layer may be formed by dry plating or by wet plating. Examples of dry plating methods include physical vapor deposition (PVD) methods such as sputtering, ion plating, and vacuum deposition, and chemical vapor deposition (CVD) methods such as thermal CVD and plasma CVD. Examples of wet plating methods include electroless plating. Dry plating is preferred from the viewpoint of forming a thin plating seed layer with a more uniform thickness, and among these, sputtering is particularly preferred from the viewpoint of realizing fine wiring with excellent adhesion strength.

[0060] Next, a mask pattern is formed on the formed plating seed layer, exposing a portion of the plating seed layer corresponding to the desired wiring pattern. After forming a metal layer on the exposed plating seed layer by electroplating, the mask pattern is removed. The conductive material used for the metal layer is not particularly limited. In a preferred embodiment, the metal layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The metal layer may be a single metal layer or an alloy layer. Examples of alloy layers include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy).

[0061] Subsequently, the unnecessary plating seed layer can be removed by etching or other means to form a conductor layer having the desired wiring pattern (hereinafter also referred to as the "conductor pattern").

[0062] According to the manufacturing method of the present invention, a conductor pattern with an L / S ratio of preferably 5 / 5 μm or less, more preferably 4 / 4 μm or less, and even more preferably 3 / 3 μm or less or 2 / 2 μm or less can be formed, and even a conductor pattern with an L / S ratio of 1 / 1 μm can be suitably formed. According to the manufacturing method of the present invention, such a conductor pattern with a small L / S ratio can be formed with a thickness of preferably 3 μm or less, 2.5 μm or less, 2 μm or less, 1.5 μm or less, or 1 μm or less. The lower limit of the thickness of the conductor pattern can be, for example, 0.5 μm or more, 0.6 μm or more, etc.

[0063] The above steps (X) and (1) to (4) are collectively referred to as the redistribution formation process. By repeatedly performing the redistribution formation process, a multilayer redistribution layer can be formed. When forming a multilayer redistribution layer, it is preferable to apply the manufacturing method of the present invention when forming the redistribution layer on the semiconductor chip side (generally, the first redistribution layer formed in the chip 1st method, and the last redistribution layer formed in the redistribution 1st method), but the manufacturing method of the present invention may also be applied to all of the multilayer redistribution layers.

[0064] According to the manufacturing method of the present invention, circuit boards such as WLP and PLP can be realized using a large-area substrate while suppressing the generation of interfacial voids and the increase in the surface potential of the support.

[0065] The manufacturing methods for circuit boards such as WLP and PLP are as described above, with reference to patent documents. For example, when manufacturing a fan-in structure WLP, a semiconductor wafer having a circuit element having a predetermined function and an electrode pad surface on which multiple electrode pads electrically connected to this circuit element are formed can be used as the "substrate," and step (X) can be performed so that the electrode pad surface and the resin composition layer are bonded. Then, by performing steps (1), (2), (3), and (4) in order, a redistribution layer can be formed on the electrode pad surface of the semiconductor wafer. By repeatedly performing these steps, it is also possible to form a multilayer redistribution layer. Then, by forming board connection terminals such as bumps on the side of the redistribution layer opposite to the semiconductor wafer and separating it into individual pieces, a fan-in structure WLP can be manufactured.

[0066] For example, when manufacturing a fan-out structured WLP, a semiconductor wafer having a circuit element with a predetermined function and multiple electrode pads electrically connected to this circuit element is first separated into individual pieces. Then, each semiconductor chip is placed on a carrier substrate (glass substrate, metal substrate, plastic substrate, etc.) spaced apart from each other, and then sealed with resin to obtain a substrate in which the separated semiconductor chips are sealed with sealing resin so that their electrode pad surfaces are exposed. Using such a substrate as a "base material," process (X) can be carried out so that the surface of the substrate on the electrode pad side is bonded to the resin composition layer. Then, by sequentially carrying out processes (1), (2), (3), and (4), a redistribution layer can be formed on the electrode pad surface of the semiconductor chip and the surrounding sealing resin layer. By repeatedly carrying out these processes, it is also possible to form a multilayer redistribution layer. Then, board connection terminals such as bumps are formed on the side of the redistribution layer opposite to the substrate, and the wafer is separated again to manufacture a fan-out structured WLP.

[0067] In particular, the fan-out structure WLP and PLP obtained by the manufacturing method of the present invention are advantageous because, combined with the inherent feature of the fan-out structure that allows for the formation of a redistribution layer over a large area, they provide an insulating layer that highly satisfies dielectric properties and low warpage requirements, while also enabling the formation of extremely fine and high-density wiring over a large area. Therefore, in one embodiment, the circuit board manufactured by the manufacturing method of the present invention is a WLP or a PLP, and more preferably a fan-out structure WLP (FOWLP) or a fan-out structure PLP (FOPLP).

[0068] While circuit board manufacturing methods such as WLP and PLP have undergone diverse developments from the perspectives of the aforementioned chip-first manufacturing method and redistribution layer-first manufacturing method, as well as from the perspective of chip mounting direction (face-down type, face-up type), the present invention relates to a highly versatile technology that can be broadly applied to the manufacturing of circuit boards that include a process of laminating a resin sheet onto a substrate during the manufacturing process. For example, as mentioned above, the circuit board manufacturing method of the present invention can be applied not only to the formation of the redistribution layer, but also to the formation of the sealing layer and the solder resist layer.

[0069] [Resin sheet] The resin sheet used in the manufacturing method of the present invention (hereinafter also simply referred to as "the resin sheet of the present invention") will be described below.

[0070] The resin sheet of the present invention comprises a support having first and second surfaces and a resin composition layer provided on the second surface of the support, and satisfies the following conditions (ii-1) and (ii-2). (ii-1) The total specific surface area of ​​the inorganic filler in the resin composition layer is 1.5 m² 2 / g or more (calculated on non-volatile components) (ii-2) The surface resistivity of the first surface of the support is 1.0 × 10 10 It is less than or equal to Ω / sq.

[0071] <Resin composition layer> In combination with the aforementioned condition (i), the resin composition layer contains an inorganic filler to satisfy the above condition (ii-1) in order to suppress the generation of interfacial voids.

[0072] -Inorganic filler- The "total specific surface area of ​​inorganic fillers in the resin composition layer" in condition (ii-1) refers to the total surface area of ​​inorganic fillers contained per gram of non-volatile components in the resin composition layer. The total specific surface area of ​​inorganic fillers in the resin composition layer is calculated by multiplying the specific surface area of ​​the inorganic fillers by A[m²]. 2 When the amount of inorganic filler is set to [ / g] and the amount of nonvolatile components in the resin composition layer is set to 100% by mass, then the amount of inorganic filler can be calculated using the formula: (A × B) / 100. Here, when multiple types of inorganic fillers are used in combination, the specific surface area of ​​all inorganic fillers contained in the resin composition layer should be set to A, and the amount of all inorganic fillers should be set to B, and the calculation should be performed accordingly.

[0073] In combination with the aforementioned condition (i), from the viewpoint of suppressing the generation of interfacial voids, the total specific surface area of ​​the inorganic filler in the resin composition layer is 1.5 m². 2 The value is 2.0 m or more, preferably 2.0 m 2 / g or more, more preferably 2.5m 2 / g or more, more preferably 3.0m 2 / g or more or 3.5m 2 The amount is 1 / g or more. The manufacturing method of the present invention, which satisfies condition (ii-1) in combination with the aforementioned condition (i) and further satisfies condition (ii-2), can suppress the increase in the surface potential of the support while further increasing the total specific surface area of ​​the inorganic filler. For example, the total specific surface area of ​​the inorganic filler in the resin composition is 4.0 m². 2 / g or more, 5.0m 2 / g or more, 6.0m 2 / g or more, 7.0m 2 / g or more, 8.0m 2 / g or more or 9.0m 2 The amount may be increased to more than / g. Therefore, in one preferred embodiment, the total specific surface area of ​​the inorganic filler in the resin composition layer is 4.0m². 2The content is 1 / g or more. In order to improve the properties of the formed insulating layer, including low dielectric loss tangent and low thermal expansion coefficient, it is beneficial to incorporate inorganic fillers in a high content. The manufacturing method of the present invention, which can increase the total specific surface area of ​​the inorganic fillers in the resin composition layer while suppressing the increase in the surface potential of the support, makes a significant contribution to highly satisfying the various functions required of the insulating layer of a circuit board.

[0074] From the viewpoint of suppressing an increase in the surface potential of the support, the upper limit of the total specific surface area of ​​the inorganic filler in the resin composition layer is preferably 25m. 2 / g or less, 20m 2 / g or less, 18m 2 / g or less, 16m 2 / g or less or 15m 2 It is less than / g.

[0075] Examples of inorganic filler materials include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Spherical silica is also preferred. Inorganic fillers may be used individually or in combination of two or more types.

[0076] Examples of commercially available inorganic fillers include "SP60-05" and "SP507-05" from Nippon Steel Chemical & Material Co., Ltd.; "SC2500SQ", "SO-C4", "SO-C2", "SO-C1", "YC100C", "YA050C", "YA050C-MJE", and "YA010C" from Admatex Co., Ltd.; "UFP-30", "DAW-03", and "FB-105FD" from Denka Co., Ltd.; "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" from Tokuyama Corporation; "Cellspheres" and "MGH-005" from Taiheiyo Cement Corporation; and "Esferique" and "BA-1" from JGC Catalysts & Chemicals Co., Ltd.

[0077] The average particle size of the inorganic filler is preferably 3 μm or less, more preferably 2 μm or less, even more preferably 1 μm or less, 0.8 μm or less, 0.6 μm or less, 0.5 μm or less, 0.4 μm or less, or 0.3 μm or less, from the viewpoint of easily achieving an insulating layer with low surface roughness after desmear treatment. The lower limit of the average particle size is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.07 μm or more, 0.1 μm or more, or 0.2 μm or more. The average particle size of the inorganic filler can be measured by the laser diffraction-scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be created on a volume basis using a laser diffraction-scattering particle size distribution analyzer, and the average particle size can be measured by taking the median diameter as the average particle size. A sample can be used in which 100 mg of inorganic filler and 10 g of methyl ethyl ketone are weighed into a vial and dispersed using ultrasound for 10 minutes. The particle size distribution of the inorganic filler was measured using a laser diffraction particle size distribution analyzer with blue and red light source wavelengths, employing a flow cell method. The average particle size was calculated as the median diameter from the obtained particle size distribution. Examples of laser diffraction particle size distribution analyzers include the "LA-960" manufactured by Horiba, Ltd.

[0078] The specific surface area (A) of the inorganic filler is not particularly limited as long as it satisfies the preferred range of "total specific surface area of ​​inorganic fillers in the resin composition layer" in relation to the inorganic filler content (B) in the resin composition, but preferably 2m 2 / g or more, more preferably 4m 2 / g or more, more preferably 5m 2 / g or more, 6m 2 / g or more, 8m 2 / g or more or 10m 2 The specific surface area is 100 m² or more. The upper limit of the specific surface area is not particularly limited, but is preferably 100 m². 2 / g or less, more preferably 80m 2 / g or less, more preferably 60mg 2 / g or less or 50ml 2 The value is less than / g. The specific surface area of ​​the inorganic filler is obtained by adsorbing nitrogen gas onto the sample surface using a specific surface area measuring device (Macsorb HM-1210, manufactured by Mountec Co., Ltd.) according to the BET method, and then calculating the specific surface area using the BET multipoint method.

[0079] The inorganic filler may be a non-hollow inorganic filler with 0 volume% porosity (preferably non-hollow silica), a hollow inorganic filler with more than 0 volume% porosity (preferably hollow silica), or may contain both. The inorganic filler may contain only a non-hollow inorganic filler (preferably non-hollow silica), only a hollow inorganic filler (preferably hollow silica), or a combination of a non-hollow inorganic filler (preferably non-hollow silica) and a hollow inorganic filler (preferably hollow silica). When the inorganic filler contains a hollow inorganic filler, it is preferable because it is easier to realize a resin composition that produces a cured product exhibiting even better dielectric properties by keeping the dielectric constant lower. The porosity of the hollow inorganic filler is preferably 10 volume% or more, more preferably 15 volume% or more, and even more preferably 20 volume% or more, with an upper limit of preferably 90 volume% or less, more preferably 85 volume% or less, even more preferably 80 volume% or less, 75 volume% or less, 70 volume% or less, 65 volume% or less, 60 volume% or less, 55 volume% or less, or 50 volume% or less. The porosity P (volume%) of the inorganic filler is defined as the volume-based ratio of the total volume of pores (total volume of pores / volume of particle) to the total volume of the particle based on the outer surface of the particle, for example, the measured value D of the actual density of the inorganic filler. M (g / cm 3 ), and the theoretical value D of the material density of the material forming the inorganic filler. T (g / cm 3 It is calculated using the following formula (1).

[0080]

number

[0081] The actual density of inorganic fillers can be measured, for example, using a true density analyzer. Examples of true density analyzers include the ULTRAPYCNOMETER 1000 manufactured by QUANTACHROME. Nitrogen is used as the measurement gas.

[0082] It is preferable that the inorganic filler is surface-treated with an appropriate surface treatment agent. Surface treatment can improve the moisture resistance and dispersibility of the inorganic filler. Examples of surface treatment agents include silane coupling agents such as vinyl-based silane coupling agents, epoxy-based silane coupling agents, styryl-based silane coupling agents, (meth)acrylic-based silane coupling agents, amino-based silane coupling agents, isocyanurate-based silane coupling agents, ureido-based silane coupling agents, mercapto-based silane coupling agents, isocyanate-based silane coupling agents, and acid anhydride-based silane coupling agents; non-silane coupling alkoxysilane compounds such as methyltrimethoxysilane and phenyltrimethoxysilane; and silazane compounds. The surface treatment agent may be used alone or in combination of two or more types.

[0083] Examples of commercially available surface treatment agents include "KBM403" (3-glycidoxypropyltrimethoxysilane), "KBM803" (3-mercaptopropyltrimethoxysilane), "KBE903" (3-aminopropyltriethoxysilane), "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), and "SZ-31" (hexamethyldisilazane), all manufactured by Shin-Etsu Chemical Co., Ltd.

[0084] From the viewpoint of improving the dispersibility of the inorganic filler, the degree of surface treatment by the surface treatment agent is preferably within a predetermined range. Specifically, it is preferable that 100% by mass of the inorganic filler is surface-treated with 0.2 to 5% by mass of the surface treatment agent.

[0085] The degree of surface treatment by a 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 should be 0.02 mg / m². 2 The above is preferred, and 0.1 mg / m² 2 The above is more preferable, 0.2 mg / m² 2 The above is even more preferable. On the other hand, from the viewpoint of preventing an increase in the melt viscosity of the resin composition layer, 1.0 mg / m2 The following is preferred: 0.8 mg / m² 2 The following is more preferable: 0.5 mg / m² 2 The following is even more preferable. The amount of carbon per unit surface area of ​​the inorganic filler can be measured after washing the inorganic filler with a solvent (e.g., methyl ethyl ketone (MEK)) after surface treatment. Specifically, a sufficient amount of MEK as the 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 solids, the amount of carbon per unit surface area of ​​the inorganic filler can be measured using a carbon analyzer. As a carbon analyzer, the "EMIA-320V" manufactured by Horiba, Ltd. can be used.

[0086] The content of inorganic filler in the resin composition layer (B) is not particularly limited as long as it satisfies the preferred range of "total specific surface area of ​​inorganic filler in the resin composition layer" in relation to the specific surface area of ​​inorganic filler (A) above. However, from the viewpoint of realizing an insulating layer with good properties such as low dielectric loss tangent and low thermal expansion coefficient, when the nonvolatile component in the resin composition layer is taken as 100% by mass, it is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 45% by mass or more, 50% by mass or more, 55% by mass or more, 60% by mass or more, 65% by mass or more, 66% by mass or more, 68% by mass or more, 70% by mass or more, 72% by mass or more, 74% by mass or more, or 75% by mass or more. The upper limit of the inorganic filler content is preferably 90% by mass or less, more preferably 85% by mass or less, 84% by mass or less, 82% by mass or less, or 80% by mass or less.

[0087] -Curable resin- In the resin sheet of the present invention, the resin composition layer includes a curable resin as the resin. The type of curable resin is not particularly limited as long as it hardens to form an insulating layer. Preferably, the curable resin is one or more selected from the group consisting of thermosetting resins and radical polymerizable resins, as they have good properties including insulating properties and heat resistance.

[0088] Examples of thermosetting resins include epoxy resins, benzocyclobutene resins, epoxy acrylate resins, urethane acrylate resins, urethane resins, polyimide resins, melamine resins, and silicone resins. The thermosetting resin may be used alone or in combination of two or more types. In particular, from the viewpoint of satisfying the properties required for the insulating layer of a circuit board, such as good dielectric properties and low warpage, it is preferable that the curable resin includes epoxy resin.

[0089] The type of epoxy resin is not particularly limited, as long as it has one or more (preferably two or more) epoxy groups in one molecule. Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, naphthylene ether type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, phenol aralkyl type epoxy resin, biphenyl aralkyl type epoxy resin, fluorene skeleton type epoxy resin, dicyclopentadiene type epoxy resin, anthracene type epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiroring-containing epoxy resin, cyclohexanedimethanol type epoxy resin, trimethylol type epoxy resin, halogenated epoxy resin, and the like.

[0090] Epoxy resins can be classified into liquid epoxy resins at 20°C (hereinafter referred to as "liquid epoxy resins") and solid epoxy resins at 20°C (hereinafter referred to as "solid epoxy resins"). In the resin sheet of the present invention, the resin composition layer may contain only liquid epoxy resin, only solid epoxy resin, or a combination of liquid epoxy resin and solid epoxy resin as the curable resin. When a combination of liquid epoxy resin and solid epoxy resin is included, the mixing ratio (liquid:solid) may be in the range of 20:1 to 1:20 by mass ratio (preferably 10:1 to 1:10, more preferably 3:1 to 1:3).

[0091] 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. As the solid epoxy resin, bixylenol type epoxy resin, naphthalene type epoxy resin, naphthalene type tetrafunctional epoxy resin, naphthol novolac type epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, naphthylene ether type epoxy resin, anthracene type epoxy resin, bisphenol A type epoxy resin, bisphenol AF type epoxy resin, phenol aralkyl type epoxy resin, tetraphenylethane type epoxy resin, phenolphthalein type epoxy resin.

[0092] Specific examples of solid epoxy resins include DIC's "HP4032H" (naphthalene-type epoxy resin); DIC's "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resins); DIC's "N-690" (cresol novolac-type epoxy resin); DIC's "N-695" (cresol novolac-type epoxy resin); DIC's "HP-7200", "HP-7200HH", "HP-7200H", and "HP-7200L" (dicyclopentadiene-type epoxy resins); and DIC's "EXA-7 311", EXA-7311-G3", 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" (naphthylene ether type epoxy resin). Phthalene-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", "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; "YX770" manufactured by Mitsubishi Chemical Corporation Examples include "0" (phenol aralkyl type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemical Co., Ltd.; "YX7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation; and "WHR991S" (phenolphthalein-imidine type epoxy resin) manufactured by Nippon Kayaku Co., Ltd. These can be used individually or in combination of two or more types.

[0093] As the liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferred. Preferred liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, hydrogenated bisphenol A type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, and epoxy resin having a butadiene structure.

[0094] Specific examples of liquid epoxy resins include DIC's "HP4032," "HP4032D," and "HP4032SS" (naphthalene-type epoxy resin); Mitsubishi Chemical's "828US," "828EL," "jER828EL," and "825" (bisphenol A-type epoxy resin); Mitsubishi Chemical's "jER807" and "1750" (bisphenol F-type epoxy resin); Mitsubishi Chemical's "jER152" (phenol novolac-type epoxy resin); Mitsubishi Chemical's "630," "630LSD," and "604" (glycidylamine-type epoxy resin); ADEKA's "ED-523T" (glycyrrol-type epoxy resin); ADEKA's "EP-3950L" and "EP-3980S" (glycidylamine-type epoxy resin); and ADEKA's "EP-4088S" (glycidylamine-type epoxy resin). Examples include chloropentadiene-type epoxy resins; "ZX1059" (a mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "EX-721" (glycidyl ester-type epoxy resin) manufactured by Nagase ChemteX Corporation; "Celoxide 2021P" (alicyclic epoxy resin with an ester skeleton) manufactured by Daicel Corporation; "PB-3600" manufactured by Daicel Corporation; "JP-100" and "JP-200" (epoxy resins with a butadiene structure) manufactured by Nippon Soda Co., Ltd.; "ZX1658" and "ZX1658GS" (1,4-glycidylcyclohexane-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX8000" (hydrogenated bisphenol A-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; and "KF-101" (epoxy-modified silicone resin) manufactured by Shin-Etsu Chemical Co., Ltd. These can be used individually or in combination of two or more types.

[0095] The epoxy group equivalent of the epoxy resin is preferably 50 g / eq. to 2000 g / eq., more preferably 60 g / eq. to 1000 g / eq., and even more preferably 80 g / eq. to 500 g / eq. The epoxy group equivalent is the mass of the epoxy resin containing one equivalent of epoxy groups, and can be measured according to JIS K7236.

[0096] 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 Mw of the epoxy resin can be measured as a polystyrene equivalent value by the GPC method.

[0097] The type of radical polymerizable resin is not particularly limited, as long as it has one or more (preferably two or more) radical polymerizable unsaturated groups per molecule. Examples of radical polymerizable resins include resins having one or more radical polymerizable unsaturated groups selected from maleimide, vinyl, allyl, styryl, vinylphenyl, acryloyl, methacryloyl, fumaroyl, and maleoil groups. In particular, from the viewpoint of satisfying the properties required for the insulating layer of a circuit board, such as good dielectric properties and low warpage, it is preferable that the curable resin contains one or more selected from maleimide resin, (meth)acrylic resin, and styryl resin.

[0098] The type of maleimide resin is not particularly limited, as long as it has one or more (preferably two or more) maleimide groups (2,5-dihydro-2,5-dioxo-1H-pyrrole-1-yl groups) per molecule. Examples of maleimide resins include: (1) maleimide resins containing a 36-carbon aliphatic skeleton derived from dimeramine, such as "BMI-3000J", "BMI-5000", "BMI-1400", "BMI-1500", "BMI-1700", and "BMI-689" (all manufactured by Dejikner Molecules); (2) maleimide resins containing an indan skeleton, as described in the Japan Institute of Invention and Innovation Publication No. 2020-500211 (commercial products include "MIR-5000-60T" (manufactured by Nippon Kayaku Co., Ltd.)); and (3) maleimide resins containing an aromatic ring skeleton directly bonded to the nitrogen atom of the maleimide group, such as "MIR-3000-70MT" (manufactured by Nippon Kayaku Co., Ltd.), "BMI-4000" (manufactured by Yamato Kasei Co., Ltd.), and "BMI-80" (manufactured by Kei-I Kasei Co., Ltd.).

[0099] The type of (meth)acrylic resin is not particularly limited as long as it has one or more (preferably two or more) (meth)acryloyl groups in one molecule, and may be a monomer or oligomer. Here, the term "(meth)acryloyl group" is a general term for acryloyl groups and methacryloyl groups. Examples of methacrylic resins include (meth)acrylate monomers, as well as (meth)acrylic resins such as "A-DOG" (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), "DCP-A" (manufactured by Kyoeisha Chemical Co., Ltd.), "NPDGA", "FM-400", "R-687", "THE-330", "PET-30", and "DPHA" (all manufactured by Nippon Kayaku Co., Ltd.).

[0100] The type of styryl resin is not particularly limited as long as it has one or more (preferably two or more) styryl groups or vinylphenyl groups in one molecule, and may be a monomer or oligomer. Examples of styryl resins include styrene monomer, as well as styryl resins such as "OPE-2St," "OPE-2St 1200," and "OPE-2St 2200" (all manufactured by Mitsubishi Gas Chemical Company).

[0101] In the resin sheet of the present invention, the resin composition layer may contain only a thermosetting resin, only a radical polymerizable resin, or a combination of a thermosetting resin and a radical polymerizable resin as the curable resin.

[0102] The content of curable resin in the resin composition layer is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 12% by mass or more, 14% by mass or more, or 15% by mass or more, when the total resin component in the resin composition layer is considered to be 100% by mass. The upper limit of this content is not particularly limited and may be determined according to the properties required of the resin composition, but for example, it may be 80% by mass or less, 70% by mass or less, 60% by mass or less, or 50% by mass or less.

[0103] In the present invention, "resin component" refers to the non-volatile components that constitute the resin composition layer, excluding the inorganic filler described later.

[0104] In the resin composition layer, when the non-volatile component of the curable resin is set to 100% by mass, the epoxy resin content is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, 60% by mass or more, 65% by mass or more, or 70% by mass or more. The upper limit of the epoxy resin content in the curable resin is not particularly limited and may be 100% by mass, but may also be, for example, 95% by mass or less, 90% by mass or less.

[0105] -Hardening agent- In the resin sheet of the present invention, the resin composition layer may contain a curing agent. The curing agent typically has the function of curing the resin composition by reacting with the curable resin.

[0106] Examples of curing agents include active ester-based curing agents, phenol-based curing agents, naphthol-based curing agents, acid anhydride-based curing agents, cyanate ester-based curing agents, carbodiimide-based curing agents, and amine-based curing agents. The curing agent may be used alone or in combination of two or more types.

[0107] In particular, from the viewpoint of producing a cured product (insulating layer) with excellent dielectric properties and conductor adhesion, the curing agent preferably contains one or more selected from the group consisting of active ester curing agents, phenol curing agents, and naphthol curing agents, and more preferably contains an active ester curing agent from the viewpoint of producing a cured product with excellent dielectric properties. Therefore, in one embodiment, the curing agent contains one or more selected from the group consisting of active ester curing agents, phenol curing agents, and naphthol curing agents, and more preferably contains an active ester curing agent.

[0108] As the active ester curing agent, compounds having one or more active ester groups in one molecule can be used. Among these, compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are preferred as the active ester curing agent. The active ester curing agent is preferably 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. In particular, from the viewpoint of improving heat resistance, an active ester curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester curing agent obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferred.

[0109] Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

[0110] Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, 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 novolac. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by the condensation of two phenol molecules with one dicyclopentadiene molecule.

[0111] Preferred examples of active ester curing agents include active ester curing agents containing a dicyclopentadiene-type diphenol structure, active ester curing agents containing a naphthalene structure, active ester curing agents containing an acetylated phenol novolac, and active ester curing agents containing a benzoylated phenol novolac. Among these, active ester curing agents containing a naphthalene structure and active ester curing agents containing a dicyclopentadiene-type diphenol structure are more preferred. The term "dicyclopentadiene-type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

[0112] Commercially available active ester compounds include: "EXB9451", "EXB9460", "EXB9460S", "HPC-8000L-65TM", "HPC-8000-65T", and "HPC-8000H-65TM" (manufactured by DIC Corporation) as active ester compounds containing a naphthalene structure; "EXB-8100L-65T", "EXB-9416-70BK", and "HPC-8150-62T" (manufactured by DIC Corporation); phosphorus Examples of active ester compounds include "EXB9401" (manufactured by DIC Corporation), "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester compound that is an acetylated phenol novolac, "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester compounds that are benzoylated phenol novolacs, and "PC1300-02-65MA" (manufactured by Air Water Corporation) as an active ester compound containing a styryl group and a naphthalene structure.

[0113] From the viewpoint of heat resistance and water resistance, phenolic and naphthol curing agents having a novolac structure are preferred. Furthermore, from the viewpoint of adhesion to the conductive layer, nitrogen-containing phenolic and nitrogen-containing naphthol curing agents are preferred, and triazine skeleton-containing phenolic and triazine skeleton-containing naphthol curing agents are more preferred.

[0114] Specific examples of phenol-based and naphthol-based curing agents include, for example, "MEH-7700", "MEH-7810", "MEH-7851", and "MEH-8000H" from Meiwa Kasei Co., Ltd.; "NHN", "CBN", and "GPH" from Nippon Kayaku Co., Ltd.; and "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", and "SN-" from Nippon Steel Chemical & Material Co., Ltd. Examples include "495V", "SN-375", "SN-395"; DIC Corporation's "TD-2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P", "EXB-9500", "HPC-9500", "KA-1160", "KA-1163", "KA-1165"; and Gun-ei Chemical Co., Ltd.'s "GDP-6115L", "GDP-6115H", "ELPC75", etc.

[0115] Examples of acid anhydride-based curing agents include curing agents having one or more acid anhydride groups in one molecule. Specific examples of acid anhydride-based curing agents 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-cyclohexen-1,2-dicarboxylic acid anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenone tetracarboxylic acid di Examples of acid anhydrides include anhydrides, biphenyltetracarboxylic acid dianhydride, naphthalenetetracarboxylic acid dianhydride, oxydiphthalic acid dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic acid 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 polymer-type acid anhydrides such as styrene-maleic acid resin copolymerized with styrene and maleic acid. A commercially available acid anhydride-based curing agent is "MH-700" manufactured by Shin Nippon Rika Co., Ltd.

[0116] 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; polyfunctional cyanate resins derived from phenol novolacs and cresol novolacs, etc.; and prepolymers in which these cyanate resins are partially triazined. Specific examples of cyanate ester-based curing agents include "PT30" and "PT60" (phenol novolac type polyfunctional cyanate ester resin), "ULL-950S" (polyfunctional cyanate ester resin), "BA230", and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate is triazined and trimerized), all manufactured by Lonza Japan.

[0117] Specific examples of carbodiimide-based curing agents include Carbodilite® V-03 (carbodiimide group equivalent: 216 g / eq.), V-05 (carbodiimide group equivalent: 262 g / eq.), V-07 (carbodiimide group equivalent: 200 g / eq.), V-09 (carbodiimide group equivalent: 200 g / eq.) manufactured by Nisshinbo Chemical Corporation, and Stavaxol® P (carbodiimide group equivalent: 302 g / eq.) manufactured by Rhein Chemie.

[0118] Examples of amine-based curing agents include curing agents having one or more amino groups in one molecule, such as aliphatic amines, polyetheramines, alicyclic amines, and aromatic amines. Specific examples of amine-based curing agents include 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 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-hydroxy Examples include bis(4-(4-aminophenoxy)phenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 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, etc. Commercial amine-based curing agents may also be used, such as "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD AA", "KAYAHARD AB", and "KAYAHARD AS" from Nippon Kayaku Co., Ltd., and "Epicure W" from Mitsubishi Chemical Corporation.

[0119] From the viewpoint of producing a cured product with excellent dielectric properties and conductor adhesion, the content of the curing agent in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, 20% by mass or more, 25% by mass or more, or 30% by mass or more, when the resin component in the resin composition is considered to be 100% by mass. The upper limit of the content is not particularly limited and may be determined according to the properties required of the resin composition, but for example, it may be 70% by mass or less, 60% by mass or less, or 55% by mass or less.

[0120] As mentioned above, from the viewpoint of obtaining a cured product with excellent dielectric properties, it is preferable that the curing agent contains an active ester-based curing agent. When the resin composition layer contains an active ester-based curing agent as the curing agent, from the viewpoint of obtaining a cured product exhibiting particularly excellent dielectric properties, the content of the active ester-based curing agent in the curing agent is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, 75% by mass or more, or 80% by mass or more, when the non-volatile components of the curing agent are considered to be 100% by mass. The upper limit of the content of the active ester-based curing agent in the curing agent is not particularly limited and may be 100% by mass, but may be, for example, 95% by mass or less, 90% by mass or less.

[0121] When the resin composition layer contains an active ester-based curing agent as a curing agent, the mass ratio of the active ester-based curing agent to the curable resin (active ester-based curing agent / curable resin) is preferably 0.5 or higher, more preferably 0.6 or higher, and even more preferably 0.7 or higher or 0.8 or higher, from the viewpoint of exhibiting particularly excellent dielectric properties. The upper limit of this mass ratio (active ester-based curing agent / curable resin) may be, for example, 2 or less, 1.8 or less, 1.6 or less, 1.5 or less, etc.

[0122] In one preferred embodiment, the resin composition layer comprises an inorganic filler, a curable resin, and a curing agent, and satisfies the above condition (ii-1). The resin composition layer may further contain one or more selected from the group consisting of stress-relieving agents and curing accelerators, to the extent that it satisfies the above condition (ii-1) and does not impede the effects of the present invention.

[0123] - Stress-relaxing material - The resin composition layer may further contain a stress-relieving material. By including a stress-relieving material, warping can be suppressed even when forming an insulating layer on a large-area substrate.

[0124] The stress-relaxing material is preferably a resin having one or more structures selected from polybutadiene, polysiloxane, poly(meth)acrylate, polyalkylene, polyalkylene oxy, polyisoprene, polyisobutylene, and polycarbonate structures within its molecule, and more preferably a resin having one or more structures selected from polybutadiene, poly(meth)acrylate, polyalkylene oxy, polyisoprene, polyisobutylene, and polycarbonate structures. Note that "(meth)acrylate" is a term that encompasses both methacrylate and acrylate. These structures may be included in the main chain or in the side chain.

[0125] The stress-relieving material is preferably high molecular weight from the viewpoint of suppressing warping. The number-average molecular weight (Mn) of the stress-relieving material is preferably 1,000 or more, more preferably 1,500 or more, and even more preferably 2,000 or more, 2,500 or more, 3,000 or more, 4,000 or more, or 5,000 or more. The upper limit of Mn is preferably 1,000,000 or less, more preferably 900,000 or less, 800,000 or less, or 700,000 or less. The number-average molecular weight (Mn) can be measured as a polystyrene equivalent value by gel permeation chromatography (GPC).

[0126] From the viewpoint of suppressing warping, the stress-relaxing material is preferably one or more resins selected from resins with a glass transition temperature (Tg) of 25°C or lower, and resins that are liquid at 25°C. Here, for resins where multiple Tg values ​​are observed, if the lowest Tg is 25°C or lower, it falls under the category of "resin with a Tg of 25°C or lower".

[0127] For resins with a Tg of 25°C or lower, the Tg is preferably 20°C or lower, and more preferably 15°C or lower. The lower limit of Tg is not particularly limited, but it can usually be -50°C or higher. Furthermore, for resins that are liquid at 25°C, they are preferably liquid at 20°C or lower, and more preferably liquid at 15°C or lower.

[0128] From the viewpoint of achieving an insulating layer with high cohesive force (intralayer adhesion strength) by reacting with a curable resin, the stress-relieving material preferably has functional groups that can react with a curable resin. Note that functional groups that can react with a curable resin also include functional groups that appear upon heating.

[0129] In one embodiment, the functional group that can react with a curable resin is one or more functional groups selected from the group consisting of a hydroxyl group, a carboxyl group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group, and a urethane group. Among these, the functional group is preferably a hydroxyl group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group, and a urethane group, and more preferably a hydroxyl group, an acid anhydride group, a phenolic hydroxyl group, and an epoxy group. However, when an epoxy group is included as a functional group, the number average molecular weight (Mn) is preferably 5,000 or more.

[0130] In one embodiment, the stress-relaxing material includes a resin containing a polybutadiene structure (hereinafter also referred to as "polybutadiene resin"). The polybutadiene structure may be partially or entirely hydrogenated.

[0131] Specific examples of polybutadiene resins include Clay Valley's "Ricon 130MA8," "Ricon 130MA13," "Ricon 130MA20," "Ricon 131MA5," "Ricon 131MA10," "Ricon 131MA17," "Ricon 131MA20," and "Ricon 184MA6" (polybutadiene containing acid anhydride groups), Nippon Soda's "JP-100" and "JP-200" (epoxidized polybutadiene), "GQ-1000" (polybutadiene with hydroxyl and carboxyl groups), "G-1000," "G-2000," and "G-3000" (polybutadiene with hydroxyl groups at both ends), "GI-1000," "GI-2000," and "GI-3000" (hydrogenated polybutadiene with hydroxyl groups at both ends), and Daicel. Examples include "PB3600" and "PB4700" (polybutadiene skeleton epoxy resins), "Epofriend A1005", "Epofriend A1010", and "Epofriend A1020" (epoxidized styrene, butadiene, and styrene block copolymers) from the company, and "FCA-061L" (hydrogenated polybutadiene skeleton epoxy resin) and "R-45EPT" (polybutadiene skeleton epoxy resin) from Nagase ChemteX Corporation. Examples of polybutadiene resins include hydroxyl-terminated polybutadiene, linear polymers made from diisocyanate compounds and tetrabasic acid anhydrides (polymers described in Japanese Patent Publication No. 2006-37083 and International Publication No. 2008 / 153208), and phenolic hydroxyl-containing butadiene. The butadiene structure content of the polymer is preferably 50% by mass or more, and more preferably 60% to 95% by mass. Details of the polymer can be found in Japanese Patent Publication No. 2006-37083 and International Publication No. 2008 / 153208, which are incorporated herein by reference.

[0132] In one embodiment, the stress-relaxing material includes a resin containing a poly(meth)acrylate structure (hereinafter also referred to as "poly(meth)acrylic resin"). Specific examples of poly(meth)acrylic resins include Nagase ChemteX's Teisan Resin "SG-70L", "SG-708-6", "WS-023", "SG-700AS", "SG-280TEA" (carboxyl group-containing acrylic ester copolymer resin, acid value 5-34 mgKOH / g, weight-average molecular weight 400,000-900,000, Tg -30-5℃), "SG-80H", "SG-80H-3", and "SG-P3" (epoxy group-containing acrylic ester copolymer resin, epoxy equivalent 4761-14285 g / eq, weight-average molecular weight 350,000). Examples include "SG-600TEA" and "SG-790" (hydroxyl group-containing acrylic ester copolymer resin, hydroxyl value 20-40 mgKOH / g, weight-average molecular weight 500,000-1,200,000, Tg -37--32℃), and "ME-2000" and "W-116.3" (carboxyl group-containing acrylic ester copolymer resin) from Negami Kogyo Co., Ltd., "W-197C" (hydroxyl group-containing acrylic ester copolymer resin), "KG-25" and "KG-3000" (epoxy group-containing acrylic ester copolymer resin).

[0133] In one embodiment, the stress-relaxing material includes a resin containing a polycarbonate structure (hereinafter also referred to as "polycarbonate resin"). Specific examples of polycarbonate resins include "T6002" and "T6001" (polycarbonate diols) from Asahi Kasei Chemicals, and "C-1090," "C-2090," and "C-3090" (polycarbonate diols) from Kuraray Co., Ltd. Linear polyimides made from hydroxyl-terminated polycarbonates, diisocyanate compounds, and tetrabasic acid anhydrides can also be used. The content of the polyimide resin is preferably 50% by mass or more, and more preferably 60% to 95% by mass. Details of the polyimide resin can be found in International Publication No. 2016 / 129541, which is incorporated herein by reference.

[0134] In one embodiment, the stress-relaxing material includes a resin containing a polysiloxane structure (hereinafter also referred to as "polysiloxane resin"). Specific examples of polysiloxane resins include, for example, "SMP-2006," "SMP-2003PGMEA," and "SMP-5005PGMEA" manufactured by Shin-Etsu Silicone Co., Ltd., as well as linear polyimides made from amine-terminated polysiloxanes and tetrabasic acid anhydrides (International Publication No. 2010 / 053185, Japanese Patent Publication No. 2002-12667 and Japanese Patent Publication No. 2000-319386, etc.).

[0135] In one embodiment, the stress-relaxing material includes a resin containing a polyalkylene structure and a polyalkylene oxy structure (hereinafter also referred to as "polyalkylene resin" and "polyalkylene oxy resin," respectively). Specific examples of polyalkylene resin and polyalkylene oxy resin include "PTXG-1000" and "PTXG-1800" manufactured by Asahi Kasei Fibers Co., Ltd.

[0136] In one embodiment, the stress-relieving material includes a resin containing a polyisoprene structure (hereinafter also referred to as "polyisoprene resin"). Specific examples of polyisoprene resin include "KL-610" and "KL613" manufactured by Kuraray Co., Ltd.

[0137] In one embodiment, the stress-relaxing material includes a resin containing a polyisobutylene structure (hereinafter also referred to as "polyisobutylene resin"). Specific examples of polyisobutylene resin include "SIBSTAR-073T" (styrene-isobutylene-styrene triblock copolymer) and "SIBSTAR-042D" (styrene-isobutylene diblock copolymer) manufactured by Kaneka Corporation.

[0138] In another preferred embodiment, the stress-relieving material includes an organic filler. A wide range of organic fillers containing rubber components can be used. Examples of rubber components in the organic filler include: silicone elastomers such as polydimethylsiloxane; olefin-based thermoplastic elastomers such as polybutadiene, polyisoprene, polychlorobutadiene, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-isobutylene copolymer, acrylonitrile-butadiene copolymer, isoprene-isobutylene copolymer, isobutylene-butadiene copolymer, ethylene-propylene-diene terpolymer, and ethylene-propylene-butene terpolymer; and thermoplastic elastomers such as acrylic-based thermoplastic elastomers such as propyl poly(meth)acrylate, poly(meth)acrylate, cyclohexyl poly(meth)acrylate, and poly(meth)acrylate octyl. Furthermore, silicone-based rubbers such as polyorganosiloxane rubber may be mixed into the rubber component. The rubber components contained in the rubber particles have a Tg of, for example, 0°C or lower, preferably -10°C or lower, more preferably -20°C or lower, and even more preferably -30°C or lower.

[0139] In one embodiment, the organic filler is a core-shell type rubber particle consisting of core particles containing the rubber component mentioned above and a shell portion formed by graft copolymerization of a monomer component copolymerizable with the rubber component contained in the core particles. Here, "core-shell type" does not necessarily refer only to those in which the core particles and shell portion can be clearly distinguished, but also includes those in which the boundary between the core particles and shell portion is unclear, and the core particles do not necessarily have to be completely covered by the shell portion.

[0140] Specific examples of organic fillers containing rubber components include, for example, CHT from Cheil Industries; B602 from UMGABS; Paraloid EXL-2602, Paraloid EXL-2603, Paraloid EXL-2655, Paraloid EXL-2311, Paraloid-EXL2313, Paraloid EXL-2315, Paraloid KM-330, Paraloid KM-336P, Paraloid KCZ-201 from Kureha Chemical Industries, and Metabren C from Mitsubishi Rayon. Examples include "-223A", "Metablen E-901", "Metablen S-2001", "Metablen W-450A", "Metablen SRK-200", Kaneka Corporation's "Kaneace M-511", "Kaneace M-600", "Kaneace M-400", "Kaneace M-580", "Kaneace MR-01", and Aica Industries Corporation's "Stafiloid AC3355", "Stafiloid AC3816", "Stafiloid AC3832", "Stafiloid AC4030", and "Stafiloid AC3364". These are core-shell type rubber particles.

[0141] When the resin composition layer contains a stress-relieving material, the content of the stress-relieving material in the resin composition layer is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and even more preferably 4% by mass or 5% by mass or more, when the resin component in the resin composition is considered as 100% by mass, from the viewpoint of realizing an insulating material that can suppress warping. In this regard, the inventors have found that while increasing the content of the stress-relieving material in the resin composition layer can suppress warping, in a circuit board manufacturing method that satisfies condition (ii-1) in combination with the aforementioned condition (i) and aims to suppress the generation of interface voids, the surface potential of the support tends to increase significantly to the extent that there is concern about damage to the semiconductor chip. In contrast, according to the manufacturing method of the present invention that satisfies condition (ii-1) in combination with condition (i) and further satisfies condition (ii-2), it is possible to further increase the content of the stress-relieving material while suppressing the increase in the surface potential of the support. For example, the content of the stress-relaxing material in the resin composition layer may be increased to 6% by mass or more, 8% by mass or more, 10% by mass or more, 12% by mass or more, 14% by mass or more, or 15% by mass or more, when the resin component in the resin composition is considered to be 100% by mass. The upper limit of the content is preferably 40% by mass or less, more preferably 35% by mass or less, or 30% by mass or less.

[0142] The content of the stress-relieving agent in the resin composition layer is also preferably 0.05 or more, more preferably 0.06 or more, 0.08 or more, or 0.1 or more, as the mass ratio of stress-relieving agent to the total of the curable resin and curing agent, i.e., stress-relieving agent / [curable resin + curing agent]. The upper limit of this mass ratio is preferably 3 or less, more preferably 2 or less, 1.8 or less, 1.6 or less, or 1.5 or less.

[0143] -Curing accelerator- The resin composition layer may further contain a curing accelerator. The inclusion of a curing accelerator allows for efficient adjustment of the curing time and curing temperature.

[0144] Examples of curing accelerators include organophosphine compounds such as "TPP," "TPP-K," "TPP-S," and "TPTP-S" (manufactured by Hokko Chemical Industry Co., Ltd.); imidazole compounds such as "Curesol 2MZ," "2E4MZ," "Cl1Z," "Cl1Z-CN," "Cl1Z-CNS," "Cl1Z-A," "2MZ-OK," "2MA-OK," and "2PHZ" (manufactured by Shikoku Chemicals Co., Ltd.); amine adduct compounds such as Novacure (manufactured by Asahi Kasei Corporation) and Fujicure (manufactured by Fuji Chemical Industry Co., Ltd.); amine compounds such as 1,8-diazabicyclo[5,4,0]undecene-7,4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 4-dimethylaminopyridine; and organometallic complexes or organometallic salts such as cobalt, copper, zinc, iron, nickel, manganese, and tin.

[0145] If the resin composition layer contains a curing accelerator, the content of the curing accelerator in the resin composition may be determined according to the required properties of the resin composition. When the resin component in the resin composition is considered as 100% by mass, the content is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less. The lower limit can be 0.001% by mass or more, 0.01% by mass or more, 0.05% by mass or more, etc.

[0146] -Other additives- In the resin sheet of the present invention, the resin composition layer may further contain other additives. Examples of such additives include: radical polymerization initiators such as peroxide-based radical polymerization initiators and azo-based radical polymerization initiators; thermoplastic resins such as phenoxy resins, polyvinyl acetal resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polyetheretherketone resins, and polyester resins; organometallic compounds such as organocumeric compounds, organozinc compounds, and organocubalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium dioxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as bentonite and montmorillonite; defoaming agents such as silicone-based defoaming agents, acrylic-based defoaming agents, fluorine-based defoaming agents, and vinyl resin-based defoaming agents; and benzotriazole-based ultraviolet Examples of adhesives include: ultraviolet absorbers such as ray absorbers; adhesion improvers such as urea silane; adhesion improvers such as triazole-based adhesion improvers, tetrazole-based adhesion improvers, and triazine-based adhesion improvers; antioxidants such as hindered phenol-based antioxidants; fluorescent whitening agents such as stilbene derivatives; surfactants such as fluorine-based surfactants and silicone-based surfactants; flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide); dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; and stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic acid anhydride-based stabilizers. The amount of such additives may be determined according to the properties required of the resin composition layer.

[0147] In the resin sheet of the present invention, the thickness of the resin composition layer may be determined according to the intended design of the circuit board, but is preferably 50 μm or less, more preferably 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, or 20 μm or less. The lower limit of the thickness of the resin composition layer is not particularly limited, but is usually 1 μm or more, 2 μm or more, 3 μm or more, 5 μm or more, etc.

[0148] From the viewpoint of ease of handling when laminating onto a substrate, the melt viscosity of the resin composition layer at 100°C is preferably 50,000 poise or less, more preferably 45,000 poise or less, even more preferably 40,000 poise or less, 35,000 poise or less, or 30,000 poise or less. As mentioned above, from the viewpoint of suppressing warping, it is preferable that the resin composition layer contains a stress-relieving material. In this regard, the inventors have found that when the melt viscosity of the resin composition layer in the lamination temperature range decreases, such as when the content of the stress-relieving material in the resin composition layer is increased, in a circuit board manufacturing method that satisfies condition (ii-1) in combination with the aforementioned condition (i) and aims to suppress the generation of interfacial voids, the surface potential of the support tends to increase significantly to the extent that there is concern about damage to the semiconductor chip. In contrast, according to the manufacturing method of the present invention that satisfies condition (ii-1) in combination with condition (i) and further satisfies condition (ii-2), it is possible to suppress the increase in the surface potential of the support even if the melt viscosity of the resin composition layer decreases further, such as by increasing the content of the stress-relieving material. For example, the melt viscosity of the resin composition layer at 100°C may be 25,000 poise or less, 20,000 poise or less, 18,000 poise or less, 16,000 poise or less, 15,000 poise or less, 14,000 poise or less, 12,000 poise or less, or 10,000 poise or less. From the viewpoint of further suppressing the generation of interfacial voids, the melt viscosity of the resin composition layer at 100°C is preferably 1,000 poise or more, 1,500 poise or more, or 2,000 poise or more. In the present invention, the melt viscosity of the resin composition layer at 100°C can be measured according to the method described in the <Measurement of Melt Viscosity> section below.

[0149] <Support> In the resin sheet of the present invention, the support has a first and a second surface, and the surface resistivity of the first surface is 1.0 × 10 10 It is characterized by being less than or equal to Ω / sq. (Condition (ii-2) above).

[0150] In the present invention, the first surface of the support refers to the exposed surface that is not bonded to the resin composition layer, and the second surface of the support refers to the surface that is bonded to the resin composition layer.

[0151] As mentioned above, we have found that by using a resin sheet having a resin composition layer that satisfies condition (ii-1) and performing process (X) to satisfy condition (i), the generation of interfacial voids can be suppressed even when using a large-area substrate. On the other hand, we have found that a new problem arises, particularly when the area of ​​the substrate is large, in which case the surface potential of the support rises to a degree that raises concerns about damage to the semiconductor chip. Furthermore, as mentioned above, this problem of increased surface potential tends to become more pronounced in resin composition layers that aim for further reduction of dielectric loss tangent and reduced warpage. The inventors have found that by satisfying condition (ii-2) in combination with conditions (i) and (ii-1), it is possible to suppress the generation of interfacial voids and suppress the increase in the surface potential of the support, even when applying insulating material in the form of a resin sheet to a large-area substrate.

[0152] In the manufacturing of circuit boards, from the viewpoint of suppressing an increase in the surface potential of the support, the surface resistivity of the first surface of the support is set to 1.0 × 10⁻⁶. 10 The impedance is less than or equal to Ω / sq., preferably 1.0 × 10⁻⁶. 9 Ω / sq. or less, more preferably 1.0 × 10⁻⁶ 8 Ω / sq. or less, more preferably 5.0 × 10 7 Ω / sq. or less, 1.0×10 7 Ω / sq. or less, 5.0×10 6 Ω / sq. or less, 1.0×10 6 Ω / sq. or less or 5.0 × 10⁻⁶ 5It is less than or equal to Ω / sq. The lower limit of the surface resistivity is not particularly limited, but is usually 1.0 × 10⁻⁶. 1 Ω / sq. or more, 5.0×10 1 Ω / sq. or more, 1.0×10 2 It can be Ω / sq. or higher. In this invention, the surface resistivity of the support surface can be measured according to the method described in the <Measurement of Surface Resistivity> section below.

[0153] The surface resistivity of the second surface of the support is not particularly limited, for example, 1.0 × 10⁻⁶ 15 Ω / sq. or less, 1.0×10 14 Ω / sq. or less, 5.0×10 13 It may be Ω / sq. or less, but from the viewpoint of further suppressing the increase in the surface potential of the support, it is preferably 1.0 × 10⁻⁶. 12 Ω / sq. or less, more preferably 1.0 × 10⁻⁶ 11 Ω / sq. or less, more preferably 1.0 × 10⁻⁶ 10 Ω / sq. or less, 1.0×10 9 Ω / sq. or less, 1.0×10 8 Ω / sq. or less or 5.0 × 10⁻⁶ 7 It is less than or equal to Ω / sq. The lower limit of the surface resistivity is not particularly limited, but is usually 1.0 × 10⁻⁶. 1 Ω / sq. or more, 5.0×10 1 Ω / sq. or more, 1.0×10 2 It can be set to Ω / sq. or greater, for example.

[0154] The material and composition of the support are not particularly limited, as long as they satisfy the above condition (ii-2). Examples of support materials include thermoplastic resin films, metal foils, and release paper, with thermoplastic resin films being preferred.

[0155] When using a thermoplastic resin film as a support, examples of thermoplastic resins include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), acrylics such as polycarbonate (PC) and polymethyl methacrylate (PMMA), cyclic polyolefins, triacetylcellulose (TAC), polyether sulfide (PES), polyether ketones, and polyimides. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred.

[0156] The support may have a matte finish, corona treatment, or antistatic treatment applied to the surface that bonds with the resin composition layer ("second surface"). Alternatively, a support with a release layer on the second surface may be used as the support. Examples of release agents used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins.

[0157] As described above, in the resin sheet of the present invention, the support is characterized in that the surface resistivity of its first surface is within the desired range (condition (ii-2)).

[0158] In order to satisfy the above condition (ii-2), it is preferable that the support in the resin sheet of the present invention is subjected to an antistatic treatment. Examples of such antistatic treatment include (a) providing an antistatic layer containing an antistatic agent on the first surface side (and optionally the second surface side) of the support, and (b) adding an antistatic agent to the material constituting the support.

[0159] As an antistatic agent, one or more conventionally known substances selected from, for example, conductive polymers, conductive fine particles, ionic compounds, and quaternary ammonium salt compounds may be used. Suitable examples of conductive polymers include polythiophene-based conductive polymers, polyaniline-based conductive polymers, and polypyrrole-based conductive polymers. Examples of polythiophene-based conductive polymers include polythiophene, poly(3-alkylthiophene), poly(3-thiophene-β-ethanesulfonic acid), and mixtures of polyalkylenedioxythiophene and polystyrene sulfonate (PSS) (including doped products); examples of polyaniline-based conductive polymers include polyaniline, polymethylaniline, and polymethoxyaniline; and examples of polypyrrole-based conductive polymers include polypyrrole, poly3-methylpyrrole, and poly3-octylpyrrole. Furthermore, suitable examples of conductive fine particles include conductive inorganic fine particles such as tin oxide, antimond-doped tin oxide (ATO), indium oxide-tin oxide (ITO), zinc oxide, and antimony pentoxide; fine particles in which the surface of organic fine particles such as silicone fine particles is coated with a conductive compound; and conductive fine particles such as carbon fine particles. Suitable examples of ionic compounds include nitrogen-containing onium salts, sulfur-containing onium salts, phosphorus-containing onium salts, alkali metal salts, and alkaline earth metal salts. Suitable examples of quaternary ammonium salt compounds include pyrrolidium rings, quaternary compounds of alkylamines, copolymers of these with acrylic acid or methacrylic acid, quaternary compounds of N-alkylaminoacrylamide, vinylbenzyltrimethylammonium salt, and 2-hydroxy-3-methacrylateoxypropyltrimethylammonium salt.

[0160] When an antistatic layer is provided on the first surface (and optionally the second surface) of the support as an antistatic treatment for the support, it is preferable that the antistatic layer contains a binder component in addition to the antistatic agent. The binder component is not particularly limited as long as it is a component that can disperse the antistatic agent and form a film, for example, a curable resin such as polyester resin, urethane resin, or acrylic resin may be used.

[0161] The content of the antistatic agent in the antistatic layer is not particularly limited as long as the desired surface resistivity can be achieved, and can be determined as appropriate. For example, the content of the antistatic agent is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, or 0.1% by mass or more, when the total antistatic layer is considered to be 100% by mass, and the upper limit is preferably 50% by mass or less, more preferably 30% by mass or less.

[0162] Therefore, in one embodiment, the resin sheet of the present invention is a support with an antistatic layer having an antistatic layer bonded to the first surface of the support.

[0163] The following are examples of preferred embodiments (layer configurations) of the resin sheet of the present invention using a support with an antistatic layer. (1) Resin composition layer / support / antistatic layer (2) Resin composition layer / release layer / support / antistatic layer (3) Resin composition layer / Antistatic layer / Support / Antistatic layer (4) Resin composition layer / release layer / antistatic layer / support / antistatic layer

[0164] All of the embodiments described in (1) to (4) above utilize a support with an antistatic layer, which has an antistatic layer bonded to its first surface. In embodiments (3) and (4) of these embodiments, an antistatic layer is also provided on the second surface side of the support, making it possible to reduce the surface resistivity of the second surface of the support.

[0165] Furthermore, when a release layer is provided on the second surface side of the support, the above-mentioned antistatic agent may be added to the release layer to create a release layer that exhibits antistatic properties. In such a case, the release layer will also serve as an antistatic layer.

[0166] Another method of treating a support with antistatic properties is to add the above-mentioned antistatic agent to the material constituting the support, thereby forming a support that exhibits antistatic properties. For example, if the support is a thermoplastic resin film, an antistatic agent can be added to the thermoplastic resin and then formed into a film, thereby forming a thermoplastic resin film that exhibits antistatic properties.

[0167] The following are examples of preferred embodiments (layer configurations) of the resin sheet of the present invention using a support exhibiting antistatic properties. (5) Resin composition layer / antistatic support (6) Resin composition layer / release layer / antistatic support

[0168] In the resin sheet of the present invention, the thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm. When using a support having an antistatic layer or a release layer, it is preferable that the total thickness of the support, including the thickness of the antistatic layer and the release layer, is within the above range.

[0169] The resin sheet of the present invention can be manufactured, for example, by preparing a resin varnish by dissolving a resin composition in an organic solvent, applying this resin varnish to the second surface side of a support using a die coater or the like, and then drying it to form a resin composition layer.

[0170] Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (MEK), and cyclohexanone; acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; and amide solvents such as dimethylformamide, dimethylacetamide (DMAc), and N-methylpyrrolidone. Organic solvents may be used individually or in combination of two or more.

[0171] Drying may be carried out by known methods such as heating or blowing hot air. The drying conditions are not particularly limited, but the drying should be carried out so that the amount of residual solvent in the resin composition layer is 10% by mass or less, preferably 5% by mass or less. Although it also depends on the boiling point of the organic solvent in the resin varnish, for example, when using a resin varnish containing 30% to 60% by mass of organic solvent, the resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0172] As described above, the resin sheet of the present invention comprises a support having first and second surfaces and a resin composition layer provided on the second surface of the support, and satisfies the following conditions (ii-1) and (ii-2). (ii-1) The total specific surface area of ​​the inorganic filler in the resin composition layer is 1.5 m² 2 / g or more (calculated on non-volatile components) (ii-2) The surface resistivity of the first surface of the support is 1.0 × 10 10 It is less than or equal to Ω / sq.

[0173] The resin sheet of the present invention is manufactured using the method for manufacturing a circuit board of the present invention, that is, a step of laminating a resin sheet containing a resin composition layer onto a substrate such that the resin composition layer is bonded to the substrate, under the following conditions (i): (i) Reduce the atmospheric pressure at the same time as or before the bonding of the resin composition layer and the substrate. It can be suitably used in a method for manufacturing circuit boards that satisfies the following conditions.

[0174] As a result, even when applied to large-area substrates, the generation of interfacial voids can be suppressed, and the increase in the surface potential of the support can be suppressed. Combined with the inherent advantage of using insulating materials in the form of resin sheets, which makes it easy to form insulating layers with good surface flatness even when compositional improvements are made to highly satisfy the characteristics required for the insulating layer of a circuit board, the resin sheet of the present invention significantly contributes to achieving further miniaturization of wiring while highly satisfying the characteristics required for the insulating layer of a circuit board. [Examples]

[0175] The present invention will be described in detail below with reference to examples. The present invention is not limited to these examples. In the following, "parts" and "%" refer to "parts by mass" and "mass%" respectively, unless otherwise specified. Unless otherwise specified, the temperature, pressure, and humidity conditions are room temperature (25°C), atmospheric pressure (1 atm), and 50% RH.

[0176] First, we will explain the various measurement and evaluation methods.

[0177] <Measurement of melt viscosity> The melt viscosity of the resin composition layer of the resin sheets prepared in the examples and comparative examples was measured using a dynamic viscoelasticity measuring device (Rheosol-G3000, manufactured by UBM). For 1 g of sample resin composition taken from the resin composition layer, the temperature was increased from a starting temperature of 60°C to 200°C at a heating rate of 5°C / min using an 18 mm diameter parallel plate. The dynamic viscoelasticity was measured under measurement conditions of a temperature interval of 2.5°C, a frequency of 1 Hz, and a strain of 1 deg, and the melt viscosity (poise) at 100°C was measured.

[0178] <Measurement of surface resistivity> The surface resistivity (Ω / sq.) of the supports used in the examples and comparative examples was measured using a surface resistivity measuring device (ST-4, manufactured by SIMCO Japan Co., Ltd., using the double-ring electrode method).

[0179] <Evaluation of interfacial voids> (1) Lamination of resin sheets The resin sheets prepared in the examples and comparative examples were laminated onto one side of a substrate using a sheet lamination device, so that the resin composition layer was bonded to the substrate. In Comparative Example 1, after bonding the resin composition layer to the substrate, the chamber containing the resin sheet and substrate to be processed was depressurized to an atmospheric pressure of 13 hPa or less. On the other hand, in Examples 1 to 8 and Comparative Example 2, the chamber containing the resin sheet and substrate to be processed was depressurized to an atmospheric pressure of 13 hPa or less before bonding the resin composition layer to the substrate. The resin sheet was then laminated onto the substrate by pressing at a temperature of 100°C and a pressure of 5 MPa for 100 seconds.

[0180] For this evaluation, we prepared an 8-inch silicon wafer ("8inch wafer" in Table 1) and a 5cm square copper-clad laminate ("5cm CCL" in Table 1) as substrates.

[0181] (2) Evaluation of interfacial voids The resulting laminate of resin sheet and substrate was observed with an optical microscope (150x magnification) after the support was peeled off, and the presence or absence of voids at the interface between the resin composition layer and the substrate was evaluated according to the following criteria.

[0182] Evaluation criteria: ○: No voids exist. △: Voids exist (the number of voids in the plane is less than 10) ×: Voids exist (10 or more voids in the plane)

[0183] <Evaluation of surface potential> (1) Lamination of resin sheets A laminate of a resin sheet and a substrate was obtained in the same manner as described above for the evaluation of interface voids.

[0184] (2) Evaluation of surface potential The surface potential (kV) of the support material was measured using a surface potential meter (FMX-004, manufactured by Simco Japan Co., Ltd.). The surface potential was then evaluated according to the following criteria.

[0185] Evaluation criteria: 〇: Surface potential is 2 kV or less △: Surface potential is more than 2 kV and 4 kV or less ×: Surface potential is more than 4 kV

[0186] <Evaluation of warpage> (1) Lamination of resin sheet A laminate of a resin sheet and a substrate was obtained in the same manner as in the <Evaluation of interfacial voids> above, except that a 12-inch silicon wafer (referred to as "12-inch wafer" in Table 1) was used instead of an 8-inch silicon wafer as the substrate.

[0187] (2) Curing of resin composition layer The obtained laminate was put into an oven at 180 °C and heated for 90 minutes to cure the resin composition layer. The obtained substrate is referred to as "Evaluation Substrate A".

[0188] (3) Evaluation of warpage The end of the obtained Evaluation Substrate A was pressed against a horizontal table, and the distance between the end of the substrate on the opposite side of the pressed portion and the table was measured as the amount of warpage. Then, the warpage was evaluated according to the following criteria.

[0189] Warpage evaluation criteria: ○: Warpage amount is 0 mm or more and 2 mm or less ×: Warpage amount is greater than 2 mm

[0190] <Support used> The layer structure of the support used in the examples and comparative examples is as follows. Hereinafter, the right side of the support (PET film) is the "first surface" side, and the left side is the "second surface" side.

[0191] Support 1: PET film / Antistatic layer (Surface resistivity of the first surface is 1.0×10 5 Ω / sq., surface resistivity of the second surface > 1.0×10 13 Ω / sq., thickness is about 38 μm) Support 2: Release layer / PET film / Antistatic layer (Surface resistivity of the first surface is 1.0×10 5Ω / sq., surface resistivity of the second surface > 1.0 × 10⁻⁶ 13 (Ω / sq., thickness approximately 38 μm) Support 3: Release layer / Antistatic layer / PET film / Antistatic layer (Surface resistivity of the first surface: 1.0 × 10 5 Ω / sq., surface resistivity of the second surface: 1.0 × 10⁻⁶ 7 (Ω / sq., thickness approximately 38 μm) Support 4: Release layer / PET film (Surface resistivity of the first surface > 1.0 × 10) 13 Ω / sq., surface resistivity of the second surface > 1.0 × 10⁻⁶ 13 (Ω / sq., thickness approximately 38 μm)

[0192] <Synthesis Example 1> (Production of Hollow Silica Particles A) In a reaction vessel, 40 g of methanol, 0.3 g of 25% solids tetramethylammonium hydroxide aqueous solution, 0.7 g of dodecyltrimethylammonium chloride, and 0.4 g of hexane were added and stirred until dissolved. 120 g of deionized water was added to the methanol solution to precipitate emulsion droplets of hexane. Then, 0.85 g of tetramethoxysilane was slowly added, and the mixture was stirred at room temperature (25°C) for 8 hours, followed by 12 hours of aging. The resulting white precipitate was then filtered through Advantec filter paper (5C), washed with 300 mL of water, and dried at 90°C for 8 hours to obtain a dry silica particle powder.

[0193] The obtained dried powder was heated to 600°C at a rate of 1°C / min while maintaining an airflow (3 L / min) using a high-speed electric furnace (Motoyama "SK-2535E"), and then calcined at 600°C for 2 hours to remove organic components and obtain hollow silica precursor particles. 0.5 g of these hollow silica precursor particles were transferred to an alumina crucible and calcined in the aforementioned electric furnace at 1000°C under air for 72 hours to obtain hollow silica particles A (average particle size 1.6 μm, BET specific surface area 12 m²). 2 A porosity of 50% per liter was obtained.

[0194] <Synthesis Example 2> (Production of Hollow Silica Particles B) According to the description in Japanese Patent Publication No. 5940188, hollow silica particles B were synthesized. Specifically, the hollow silica particles B were synthesized by the following procedure.

[0195] Using 300 g of an aqueous water glass solution (SiO2 / Na2O molar ratio 3.2, SiO2 concentration 24% by weight), one of the two-fluid nozzles was sprayed with a flow rate of 0.12 kg / hr, and the other nozzle was sprayed with air at a flow rate of 31800 L / hr (air / liquid volume ratio 31800) into hot air at an inlet temperature of 400 °C to obtain silica-based particle precursor particles (1). At this time, the outlet temperature was 150 °C. Then, 50 g of the silica-based particle precursor particles (1) were immersed in 500 g of a sulfuric acid aqueous solution with a concentration of 10% by weight and stirred for 2 hours. Then, drying and heat treatment were performed at 90 °C for 12 hours in a dryer to obtain hollow silica particles.

[0196] The obtained hollow silica particles were heated to 600 °C at a rate of 1 °C / min while flowing air (3 L / min) using a high-speed temperature-rising electric furnace (manufactured by Motoyama Co., Ltd., "SK-2535E"), and after firing at 600 °C for 2 hours, 0.5 g of these hollow silica particles were transferred to an alumina crucible and fired at 1000 °C for 72 hours under air using the above electric furnace to obtain hollow silica particles B (average particle diameter 2.0 μm, BET specific surface area 3.8 m 2 / g, porosity 20% by volume).

[0197] <Synthesis Example 3> (Synthesis of Stress Relaxant A) Into a reaction vessel, 69 g of a bifunctional hydroxy group-terminated polybutadiene (manufactured by Nippon Soda Co., Ltd., "G-3000", number average molecular weight: 3000, hydroxy group equivalent: 1800 g / eq.), 40 g of an aromatic hydrocarbon-based mixed solvent (manufactured by Idemitsu Petrochemical Co., Ltd., "Ipzol 150"), and 0.005 g of dibutyltin laurate were added and mixed to dissolve uniformly. The obtained solution was heated to 60 °C, and 8 g of isophorone diisocyanate (manufactured by Evonik Degussa Japan Co., Ltd., "IPDI", isocyanate group equivalent: 113 g / eq.) was further added while stirring, and the reaction was carried out for about 3 hours. Thereby, a first reaction solution was obtained.

[0198] Next, 23 g of cresol novolac resin (DIC Corporation "KA-1160", hydroxyl group equivalent: 117 g / eq.) and 60 g of ethyl diglycol acetate (Daicel Corporation) were added to the first reaction solution, and the mixture was heated to 150°C while stirring, and the reaction was carried out for approximately 10 hours. This yielded the second reaction solution. FT-IR analysis was performed at 2250 cm⁻¹. -1 The disappearance of the NCO peak was confirmed. The disappearance of the NCO peak was considered the endpoint of the reaction, and the second reaction solution was cooled to room temperature. The second reaction solution was then filtered through a 100-mesh filter cloth. As a result, a solution containing stress-relieving material A (phenolic hydroxyl group-containing polybutadiene resin) with reactive functional groups as a non-volatile component (50% by mass of non-volatile component) was obtained as a filtrate. The number-average molecular weight of stress-relieving material A was 5,900, and its glass transition temperature was -7°C.

[0199] [Example 1. Preparation of resin sheet 1] (1) Preparation of resin composition 3 parts bisphenol A type epoxy resin (Mitsubishi Chemical Corporation "828EL", epoxy equivalent 189 g / eq.), 4 parts naphthylene ether type epoxy resin (DIC Corporation "HP6000", epoxy equivalent 250 g / eq.), 4 parts bixylenol type epoxy resin (Mitsubishi Chemical Corporation "YX4000H", epoxy equivalent 185 g / eq.), 2 parts stress relaxation agent (Dow Chemical Corporation "Paraloid EXL2655"), inorganic filler (Spherical silica (Admatex Corporation "SO-C2", average particle size 0.5 μm, specific surface area 5.8 m²) surface-treated with amine-based silane coupling agent (Shin-Etsu Chemical Co., Ltd. "KBM573")) 2A resin varnish was prepared by mixing 76 parts of ( / g)(6g), 3 parts of phenoxy resin (Mitsubishi Chemical's "YX7553BH30", a 1:1 solution of MEK and cyclohexanone with 30% by mass of nonvolatile content), 3 parts of phenolic curing agent (DIC's "KA-1160", phenolic hydroxyl group equivalent of 117g / eq.), 11 parts of active ester curing agent (DIC's "HPC-8000-65T", active group equivalent of 223g / eq., a toluene solution with 65% by mass of solid content), 0.05 parts of curing accelerator (4-dimethylaminopyridine (DMAP)), and 15 parts of methyl ethyl ketone, and uniformly dispersing them in a high-speed rotary mixer.

[0200] (2) Preparation of resin sheets The prepared varnish was uniformly applied to the second surface of the support 1 so that the thickness of the resin composition layer after drying was 50 μm. The varnish was then dried at 80°C to 120°C (average 100°C) for 4 minutes to produce a resin sheet 1 containing the support and the resin composition layer provided on the second surface of the support. In the obtained resin sheet 1, the total specific surface area of ​​the inorganic filler in the resin composition layer was 4.4 m². 2 It was / g.

[0201] [Example 2. Preparation of resin sheet 2] Resin sheet 2 was prepared in the same manner as in Example 1, except that support 2 was used instead of support 1. In the obtained resin sheet 2, the total specific surface area of ​​the inorganic filler in the resin composition layer was 4.4 m². 2 It was / g.

[0202] [Example 3. Preparation of resin sheet 3] A resin sheet 3 was prepared in the same manner as in Example 1, except that support 3 was used instead of support 1. In the obtained resin sheet 3, the total specific surface area of ​​the inorganic filler in the resin composition layer was 4.4 m². 2 It was / g.

[0203] [Example 4. Preparation of resin sheet 4] (1) Preparation of resin composition (i) Spherical silica (SO-C2, manufactured by Admatex, with average particle size 0.5 μm and specific surface area 5.8 m²) surface-treated with an inorganic filler (amine-based silane coupling agent (KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) 2 (ii) The amount of the inorganic filler (amine-based silane coupling agent (Spherical silica surface-treated with Shin-Etsu Chemical Co., Ltd.'s "KBM573") (Denka Co., Ltd.'s "UFP-30", average particle size 0.3 μm, specific surface area 30.7 m²) was changed from 76 parts to 50 parts. 2 A resin varnish was prepared in the same manner as in Example 1, except that 20 parts ( / g) were used.

[0204] (2) Preparation of resin sheets A resin sheet 4 was prepared in the same manner as in Example 1, except that support 2 was used instead of support 1, and a varnish of the prepared resin composition was applied to the second surface of support 2. In the obtained resin sheet 4, the total specific surface area of ​​the inorganic filler in the resin composition layer was 9.6 m². 2 It was / g.

[0205] [Example 5. Preparation of resin sheet 5] (1) Preparation of resin composition 3 parts bisphenol A type epoxy resin (Mitsubishi Chemical Corporation "828EL", epoxy equivalent 189 g / eq.), 1 part naphthylene ether type epoxy resin (DIC Corporation "HP6000", epoxy equivalent 250 g / eq.), 4 parts bixylenol type epoxy resin (Mitsubishi Chemical Corporation "YX4000H", epoxy equivalent 185 g / eq.), 2 parts stress relaxation agent (Dow Chemical Corporation "Paraloid EXL2655"), 3 parts stress relaxation agent (Nippon Soda Co., Ltd. "JP-100", epoxidized polybutadiene resin), 3 parts stress relaxation agent A, inorganic filler (spherical silica (Admatex Corporation "SO-C2", average particle size 0.5 μm, specific surface area 5.8 m²) surface-treated with amine-based silane coupling agent (Shin-Etsu Chemical Co., Ltd. "KBM573")) 2A resin varnish was prepared by mixing 76 parts of (1 / g), 2 parts of phenolic curing agent (DIC Corporation's "KA-1160", phenolic hydroxyl group equivalent 117 g / eq.), 11 parts of active ester curing agent (DIC Corporation's "HPC-8000-65T", active group equivalent 223 g / eq., toluene solution with 65% solids by mass), 0.05 parts of curing accelerator (4-dimethylaminopyridine (DMAP)), and 15 parts of methyl ethyl ketone, and uniformly dispersing them in a high-speed rotary mixer.

[0206] (2) Preparation of resin sheets A resin sheet 5 was prepared in the same manner as in Example 1, except that support 2 was used instead of support 1, and a varnish of the prepared resin composition was applied to the second surface of support 2. In the obtained resin sheet 5, the total specific surface area of ​​the inorganic filler in the resin composition layer was 4.4 m². 2 It was / g.

[0207] [Example 6. Preparation of resin sheet 6] (1) Preparation of resin composition Spherical silica (SO-C2, manufactured by Admatex Co., Ltd., with average particle size 0.5 μm and specific surface area 5.8 m²) surface-treated with an inorganic filler (amine-based silane coupling agent (KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.)) 2 Instead of 76 parts ( / g), an inorganic filler (spherical alumina surface-treated with KBM573 (average particle size 2 μm, specific surface area 2.1 m²) is used. 2 A resin composition varnish was prepared in the same manner as in Example 1, except that 110 parts of ( / g) were used.

[0208] (2) Preparation of resin sheets A resin sheet 6 was prepared in the same manner as in Example 1, except that support 3 was used instead of support 1, and a varnish of the prepared resin composition was applied to the second surface of support 3. In the obtained resin sheet 6, the total specific surface area of ​​the inorganic filler in the resin composition layer was 1.7 m². 2 It was / g.

[0209] [Example 7. Preparation of resin sheet 7] (1) Preparation of resin composition (i) The compounding quantity of the inorganic filler (spherical silica (manufactured by Admatechs Co., Ltd. "SO-C2", average particle diameter 0.5 μm, specific surface area 5.8 m 2 / g) surface-treated with an amine-based silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd. "KBM573")) was changed from 76 parts to 66 parts. (ii) A resin composition varnish was prepared in the same manner as in Example 5, except that 10 parts of hollow silica particles A were used.

[0210] (2) Production of the resin sheet A resin sheet 7 was produced in the same manner as in Example 1, except that support 3 was used instead of support 1, and the varnish of the resin composition prepared was applied to the second surface of the support 3. In the obtained resin sheet 7, the total specific surface area of the inorganic filler in the resin composition layer was 5.0 m 2 / g.

[0211] [Example 8. Production of resin sheet 8] (1) Preparation of the resin composition (i) The compounding quantity of the inorganic filler (spherical silica (manufactured by Admatechs Co., Ltd. "SO-C2", average particle diameter 0.5 μm, specific surface area 5.8 m 2 / g) surface-treated with an amine-based silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd. "KBM573")) was changed from 76 parts to 66 parts. (ii) A resin composition varnish was prepared in the same manner as in Example 5, except that 10 parts of hollow silica particles B were used.

[0212] (2) Production of the resin sheet A resin sheet 8 was produced in the same manner as in Example 1, except that support 3 was used instead of support 1, and the varnish of the resin composition prepared was applied to the second surface of the support 3. In the obtained resin sheet 8, the total specific surface area of the inorganic filler in the resin composition layer was 4.2 m 2 / g.

[0213] [Comparative Example 1. Production of resin sheet C1] (1) Preparation of the resin composition (i) The point that 2 parts of the stress relaxation material ("Paraloid EXL2655" manufactured by Dow Chemical Company) were not used, and (ii) the compounding amount of the inorganic filler (spherical silica ("SO-C2" manufactured by Admatechs Co., Ltd., average particle diameter 0.5 μm, specific surface area 5.8 m 2 / g) surface-treated with an amine-based silane coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.) was changed from 76 parts to 20 parts. Except for these points, a varnish of the resin composition was prepared in the same manner as in Example 1.

[0214] (2) Preparation of the resin sheet A resin sheet C1 was produced in the same manner as in Example 1, except that support 4 was used instead of support 1, and the varnish of the resin composition prepared was applied to the second surface of the support 4. In the obtained resin sheet C1, the total specific surface area of the inorganic filler in the resin composition layer was 2.8 m 2 / g.

[0215] [Comparative Example 2. Production of resin sheet C2] (1) Preparation of the resin composition A varnish of the resin composition was prepared in the same manner as in Example 4, except that 2 parts of the stress relaxation material ("Paraloid EXL2655" manufactured by Dow Chemical Company) were not used.

[0216] (2) Production of the resin sheet A resin sheet C2 was produced in the same manner as in Example 1, except that support 4 was used instead of support 1, and the varnish of the resin composition prepared was applied to the second surface of the support 4. In the obtained resin sheet C2, the total specific surface area of the inorganic filler in the resin composition layer was 9.8 m 2 / g.

[0217] The results of Examples 1 to 8 and Comparative Examples 1 and 2 are shown in Table 1.

[0218]

Table 1

[0219] In a study on a technique for forming an insulating layer by laminating a resin composition layer onto a substrate using a resin sheet and curing it, it was confirmed that interfacial voids tend to occur when the surface area of ​​the substrate is large (Comparative Example 1; in Comparative Example 1, after bonding the resin composition layer and the substrate, the pressure inside the chamber containing the resin sheet and substrate to be processed was reduced).

[0220] As a result of investigating a technique that can suppress the generation of interfacial voids even when applying insulating material in the form of a resin sheet to a large-area substrate, the following was found: (a) the atmospheric pressure is reduced at the same time as or before the bonding of the resin composition layer and the substrate, and (b) the total specific surface area of ​​the inorganic filler in the resin composition layer is 1.5 m². 2 We found that the generation of interfacial voids can be suppressed by adjusting the dimensions and content of the inorganic filler so that the concentration is 1 / g or more (calculated on non-volatile components) (Comparative Example 2). However, we also found that the surface potential of the support increases, especially when the surface area of ​​the substrate is large (Comparative Example 2). In Comparative Example 2 and Examples 1 to 8, the ambient pressure was reduced to the desired value before the resin composition layer and the substrate were bonded together. However, we confirmed that a similar trend (the generation of interfacial voids is suppressed, but the surface potential of the support increases) is observed when the ambient pressure is reduced simultaneously with the bonding of the resin composition layer and the substrate.

[0221] In contrast, the manufacturing method of the present invention, which satisfies all of the aforementioned conditions (i), (ii-1), and (ii-2), was found to be able to suppress the generation of interfacial voids and suppress the increase in the surface potential of the support, even when the insulating material in the form of a resin sheet is applied to a large-area substrate (Examples 1 to 8).

Claims

[Claim 1] (X) A step of laminating a resin sheet, which includes a support having first and second surfaces and a resin composition layer provided on the second surface of the support, onto a substrate such that the resin composition layer is bonded to the substrate. Includes, A method for manufacturing a circuit board that satisfies the following conditions (i), (ii-1), and (ii-2). (i) Reduce the atmospheric pressure at the same time as or before the resin composition layer and the substrate are bonded together. (ii-1) The total specific surface area of ​​the inorganic filler in the resin composition layer is 1.5 m². ２ / g or more (calculated on non-volatile components) (ii-2) The surface resistivity of the first surface of the support is 1.0 × 10 １０ It is less than or equal to Ω / sq.

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