Circuit board manufacturing method

Abstract

The present invention provides a method for manufacturing a circuit board that can suppress the separation of a conductive layer formed on an insulating layer using a resin composition containing epoxy resin and an active ester resin from the insulating layer during CZ processing. [Solution] A method for manufacturing a circuit board, comprising the steps of: (I) preparing an intermediate laminate 100 comprising an inner layer substrate 110, an intermediate cured layer 120 formed on the inner layer substrate 110, and a first conductor layer 130 bonded to the intermediate cured layer 120; (II) forming a second conductor layer 1 on a portion of the first conductor layer 130 after step (I); (III) removing the portion of the first conductor layer 130 on which the second conductor layer was not formed after step (II); and (IV) applying a heat treatment to the intermediate cured layer 120 between steps (I) and (III); wherein the intermediate cured layer 120 is a layer obtained by curing a resin composition layer containing (A) epoxy resin and (B) active ester resin.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a circuit board. [Background technology]

[0002] As a manufacturing technology for circuit boards such as printed wiring boards, a build-up method is known in which insulating layers and conductive layers are alternately stacked on an inner layer substrate. The insulating layer is generally formed by curing a resin composition (Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-151212 [Overview of the project] [Problems that the invention aims to solve]

[0004] Conductor layers are typically patterned. Patterning involves processing the conductor layer to have a desired pattern shape. Unless otherwise specified, the pattern shape refers to the shape viewed from the thickness direction. Patterned conductor layers can form wiring layers on a circuit board. Such patterning is performed by methods such as the subtractive method and the modified semi-additive method.

[0005] From the viewpoint of adjusting the properties of the insulating layer and improving the adhesion between the insulating layer and the conductive layer, a resin composition layer may be subjected to a curing treatment to obtain an intermediate cured layer, a conductive layer may be formed on the intermediate cured layer, and then the intermediate cured layer may be subjected to a heat treatment to obtain an insulating layer. Conventionally, such a heat treatment was performed after obtaining a conductive layer having a desired pattern shape by pattern processing.

[0006] Furthermore, after the formation of the conductive layer, a process was sometimes performed to create minute irregularities on the surface of the conductive layer using an etching agent such as an acid solution, in order to improve the adhesion between the conductive layer and the insulating layer formed on top of it. This process is sometimes called "CZ treatment". Conventionally, this CZ treatment was generally performed after patterning the conductive layer and then applying a heat treatment.

[0007] Improvements in properties such as dielectric properties are desired for the insulating layer of circuit boards. Therefore, the inventor attempted to improve the properties of the insulating layer by using a resin composition containing epoxy resin and activated ester resin. However, when using a resin composition containing epoxy resin and activated ester resin, parts or all of the conductor layer sometimes separated from the insulating layer during the CZ treatment process. Specifically, a phenomenon occurred in which parts or all of the conductor layer formed on the insulating layer separated from the insulating layer. This phenomenon is sometimes called the "wiring floating phenomenon".

[0008] In recent years, circuit boards have become larger, and consequently, the wiring length of the connections formed by the conductive layers of these circuit boards has increased. However, it has been found that when the wiring length is long, the aforementioned wiring lifting phenomenon tends to occur more easily. In order to meet the demand for larger circuit boards, it is necessary to suppress this wiring lifting phenomenon.

[0009] The present invention was devised in view of the above-mentioned problems, and aims to provide a method for manufacturing a circuit board that can suppress the separation of a conductive layer formed on an insulating layer using a resin composition layer containing epoxy resin and an activated ester resin from the insulating layer during CZ processing. [Means for solving the problem]

[0010] The inventors diligently studied to solve the aforementioned problems. As a result, the inventors discovered that the aforementioned problems can be solved when heat treatment is performed at an appropriate time, and thus completed the present invention. That is, the present invention includes the following:

[0011] <1> Step (I) of preparing an intermediate laminate comprising an inner layer substrate, an intermediate hardened layer formed on the inner layer substrate, and a first conductive layer bonded to the intermediate hardened layer, After step (I), step (II) is performed to form a second conductor layer on a portion of the first conductor layer. After step (II), step (III) is performed to remove the first conductor layer in the portion where the second conductor layer was not formed, and, The process includes step (IV), in which the intermediate hardened layer is subjected to heat treatment to obtain an insulating layer between steps (I) and (III); A method for manufacturing a circuit board, wherein the intermediate cured layer is a layer obtained by curing a resin composition layer containing (A) an epoxy resin and (B) an active ester resin. <2> Process (I) is, Step (I-a1) of forming a resin composition layer on an inner layer substrate, A step (I-a2) in which a resin composition layer is subjected to a curing treatment to form an intermediate cured layer, and Step (I-a3) to form the first conductive layer on the intermediate hardened layer, It includes in this order, <1> The method for manufacturing a circuit board as described above. <3> Step (I) includes a step (I-a4) between steps (I-a2) and (I-a3) in which a roughening treatment is applied to the intermediate hardened layer. <2> The method for manufacturing a circuit board as described above. <4> Process (I) is, A process (I-b1) of laminating a resin sheet comprising a metal foil having a first conductive layer and a resin composition layer bonded to the first conductive layer of the metal foil, and an inner layer substrate, such that the resin composition layer and the inner layer substrate are bonded together, and Step (I-b2) to form an intermediate cured layer by curing the resin composition layer. It includes in this order, <1> The method for manufacturing a circuit board as described above. <5> The process includes step (V) of bringing the second conductive layer into contact with an etching agent after step (III), <1> ~ <4> A method for manufacturing a circuit board as described in any one of the items. <6> The method for manufacturing a circuit board according to any one of <1> to <5>, wherein the equivalent ratio of the active ester group of the (B) active ester resin to the epoxy group of the epoxy resin is 0.1 or more. <7> The method for manufacturing a circuit board according to any one of <1> to <6>, wherein the arithmetic mean roughness Ra of the surface of the intermediate cured layer of the intermediate laminate on the side of the first conductor layer is 250 nm or less. <8> The method for manufacturing a circuit board according to any one of <1> to <7>, wherein the average linear thermal expansion coefficient CTE of the insulating layer is 25 ppm / K or less. <9> The method for manufacturing a circuit board according to any one of <1> to <8>, wherein the glass transition temperature Tg of the insulating layer is 140°C or more. <10> The method for manufacturing a circuit board according to any one of <1> to <9>, wherein the thickness of the first conductor layer is 100 nm or more and 1000 nm or less. <11> The method for manufacturing a circuit board according to any one of <1> to <10>, wherein the length of the second conductor layer after step (III) is 10 mm or more.

Advantages of the Invention

[0012] According to the present invention, there is provided a method for manufacturing a circuit board capable of suppressing the separation of a conductor layer formed on an insulating layer using a resin composition layer containing an epoxy resin and an active ester resin from the insulating layer during CZ treatment.

Brief Description of the Drawings

[0013] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an intermediate laminate prepared in step (I) according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view for explaining step (I-a1) in the method for manufacturing an intermediate laminate according to the first example. [Figure 3] FIG. 3 is a schematic cross-sectional view for explaining step (I-a2) in the method for manufacturing an intermediate laminate according to the first example. [Figure 4]Figure 4 is a schematic cross-sectional view showing a metal-coated resin sheet used in the manufacturing method of the intermediate laminate according to the second example. [Figure 5] Figure 5 is a schematic cross-sectional view illustrating step (I-b1) in the manufacturing method of the intermediate laminate according to the second example. [Figure 6] Figure 6 is a schematic cross-sectional view illustrating step (I-b2) in the manufacturing method of the intermediate laminate according to the second example. [Figure 7] Figure 7 is a schematic cross-sectional view illustrating step (II) according to one embodiment of the present invention. [Figure 8] Figure 8 is a schematic cross-sectional view illustrating step (II-1) of the method for manufacturing a circuit board according to one embodiment of the present invention. [Figure 9] Figure 9 is a schematic cross-sectional view illustrating step (II-2) of the method for manufacturing a circuit board according to one embodiment of the present invention. [Figure 10] Figure 10 is a schematic cross-sectional view illustrating step (IV) according to one embodiment of the present invention. [Figure 11] Figure 11 is a schematic cross-sectional view showing a circuit board obtained in step (III) according to one embodiment of the present invention. [Figure 12] Figure 12 is a schematic cross-sectional view showing an intermediate product comprising an insulating layer and a conductive layer in a conventional circuit board manufacturing method. [Modes for carrying out the invention]

[0014] The present invention will be described below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be modified and implemented without departing from the scope of the claims and their equivalents.

[0015] <Overview of circuit board manufacturing method> A method for manufacturing a circuit board according to one embodiment of the present invention is used to manufacture a circuit board comprising an insulating layer obtained by curing a resin composition layer containing (A) an epoxy resin and (B) an active ester resin. This manufacturing method is Step (I) of preparing an intermediate laminate comprising an inner layer substrate, an intermediate hardened layer formed on the inner layer substrate, and a first conductive layer bonded to the intermediate hardened layer, After step (I), step (II) is performed to form a second conductor layer on a portion of the first conductor layer. After step (II), step (III) is performed to remove the first conductor layer in the portion where the second conductor layer was not formed, and, Between steps (I) and (III), step (IV) is performed to obtain an insulating layer by applying heat treatment to the intermediate hardened layer. This includes the intermediate cured layer, which is a layer obtained by curing the resin composition layer. More specifically, the intermediate cured layer is a layer obtained by curing the resin composition layer, which is a layer before the heat treatment in step (IV). The insulating layer is a layer obtained by curing the resin composition layer, which is a layer after the heat treatment in step (IV). In one example, the method for manufacturing a circuit board according to this embodiment may include steps (I), (II), (IV), and (III) in this order. In another example, the method for manufacturing a circuit board according to this embodiment may include steps (I), (IV), (II), and (III) in this order.

[0016] According to this manufacturing method, the phenomenon in which a portion or the entirety of the conductor layer formed on the edge layer separates from the insulating layer due to CZ treatment (wiring lifting phenomenon) can be suppressed. The inventors of the present invention surmise that such an excellent effect is obtained as follows. However, the present invention is not limited to the following mechanism.

[0017] Conventionally, the process involved forming a conductor layer on an intermediate hardened layer, patterning the conductor layer, and then forming an insulating layer by heat treatment of the intermediate hardened layer, followed by CZ treatment. During the heat treatment, stress can be generated in the insulating layer due to the reaction of components contained in the intermediate hardened layer and the thermal expansion of the intermediate hardened layer. When the conductor layer was patterned, the aforementioned stress was concentrated at the boundary between the area where the conductor layer was formed and the area where the conductor layer was not formed.

[0018] The stress concentration at the aforementioned boundary will be explained with reference to the drawings. Figure 12 is a schematic cross-sectional view of an intermediate product 900 having an insulating layer 910 and a conductive layer 920 in a conventional circuit board manufacturing method. As shown in Figure 12, when the conductive layer 920 is patterned, a portion of the surface 910U of the insulating layer 910 (the portion where the conductive layer 920 is formed) 911U is covered by the conductive layer 920, while other portions (the portion where the conductive layer 920 is not formed) 912U may be exposed without being covered by the conductive layer 920. In the portion 911U covered by the conductive layer 920, the insulating layer 910 is constrained by the conductive layer 920, while in the portion 912U not covered by the conductive layer 920, the insulating layer 910 is not constrained by the conductive layer 920. Therefore, stress tended to concentrate in the insulating layer 910 at the boundary portion 930 of the insulating layer 910, which is located at the boundary between the portion 911U covered by the conductor layer 920 and the portion 912U not covered by the conductor layer 920. Typically, the boundary portion 930 corresponds to the portion of the insulating layer 910 that is in contact with the corner portion 921 of the patterned conductor layer 920, as shown in Figure 12.

[0019] When CZ treatment is performed under conditions of such stress concentration, the etching agent for CZ treatment, such as an acid solution, penetrates the interface between the boundary portion 930 of the insulating layer 910 and the corner portion 921 of the conductor layer 920, causing the insulating layer 910 and the conductor layer 920 to delaminate. Then, starting from the point where delamination occurred, the delamination of the insulating layer 910 and the conductor layer 920 progresses further, so conventionally, a wiring lifting phenomenon occurred where part or all of the conductor layer 920 separated from the insulating layer 910. Many conductor layers 920 are formed linearly when viewed from the thickness direction in order to form a wiring layer. In such linear conductor layers 920, the entire conductor layer 920 often delaminates in the width direction of the line, and part or all of the conductor layer 920 often delaminates in the length direction of the line.

[0020] In contrast, in the circuit board manufacturing method according to this embodiment, a heat treatment is performed before removing the first conductor layer in step (III). Therefore, at the time the heat treatment is performed, the portion of the first conductor layer that should be removed in step (III) remains. As a result, there are no boundary areas where stress concentration may occur, and stress concentration due to the heat treatment is suppressed. Consequently, the formation of peeling starting points during the CZ treatment can be suppressed, and the wiring lifting phenomenon can be suppressed.

[0021] <Step (I). Preparation of the intermediate laminate> Figure 1 is a schematic cross-sectional view showing an intermediate laminate 100 prepared in step (I) according to one embodiment of the present invention. The method for manufacturing a circuit board according to this embodiment includes a step (I) of preparing an intermediate laminate 100, as shown in Figure 1. The intermediate laminate 100 comprises an inner layer substrate 110, an intermediate hardened layer 120 formed on the inner layer substrate 110, and a first conductor layer 130 bonded to the intermediate hardened layer 120.

[0022] The inner layer substrate 110 is a component that serves as the base material for the circuit board, and examples include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, thermosetting polyphenylene ether substrates, etc. The inner layer substrate 110 may also have an arbitrary conductive layer (not shown) on one or both sides of the inner layer substrate 110. The arbitrary conductive layer on the inner layer substrate 110 may be patterned. Circuit wiring can be formed by the patterned conductive layer. Therefore, an inner layer substrate having such an arbitrary conductive layer may be called an "inner layer circuit board". Intermediate products on which an insulating layer (see insulating layer 150 shown in Figure 11) and / or a conductive layer (see conductive layer 160 in Figure 11) are further formed when manufacturing a circuit board are also included in the term "inner layer substrate" 110. Furthermore, an inner layer substrate 110 with embedded components (not shown) may be used.

[0023] The intermediate cured layer 120 is a layer obtained by curing the resin composition layer. The resin composition layer is a layer containing (A) epoxy resin and (B) activated ester resin. Specifically, the resin composition layer is a layer containing a resin composition containing (A) epoxy resin and (B) activated ester resin, and the resin composition layer may contain only the resin composition. Details of the resin composition will be described later.

[0024] The intermediate hardening layer 120 is formed on the inner layer substrate 110. The intermediate hardening layer 120 may be formed directly on the inner layer substrate 110, or it may be formed indirectly via any layer (not shown). Unless otherwise specified, "directly" forming the intermediate hardening layer 120 on the inner layer substrate 110 means that there are no other layers between the inner layer substrate 110 and the intermediate hardening layer 120. "Indirectly" forming the intermediate hardening layer 120 on the inner layer substrate 110 means that there is any layer between the inner layer substrate 110 and the intermediate hardening layer 120. Here, we will explain an example in which the inner layer substrate 110 and the intermediate hardening layer 120 are joined by the direct formation of the intermediate hardening layer 120 on the inner layer substrate 110. Furthermore, the intermediate hardening layer 120 may be formed on one side of the inner layer substrate 110, or on both sides of the inner layer substrate 110. In this embodiment, an example in which an intermediate hardened layer 120 is formed on one side of the inner layer substrate 110 will be described.

[0025] From the viewpoint of miniaturization, the thickness of the intermediate hardened layer 120 is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. The lower limit of the thickness of the intermediate hardened layer 120 can be, for example, 1 μm or more, 3 μm or more, 5 μm or more, etc.

[0026] The surface 120U of the intermediate hardened layer 120 on the first conductor layer side preferably has a small arithmetic mean roughness Ra. Specifically, the range of the arithmetic mean roughness Ra of the surface 120U of the intermediate hardened layer 120 is preferably 250 nm or less, more preferably 200 nm or less, and even more preferably 160 nm or less. Conventionally, when the arithmetic mean roughness Ra of the surface 120U of the intermediate hardened layer 120 is small, the anchoring effect is reduced, and the adhesion between the insulating layer (see insulating layer 150 in Figure 11) and the first conductor layer 130 is reduced, making it easy for the wiring to float. In contrast, the manufacturing method according to this embodiment makes it possible to suppress the wiring floating phenomenon even in configurations where the wiring floating phenomenon was conventionally prone to occur. Therefore, from the viewpoint of utilizing the effects of the present invention, it is preferable that the arithmetic mean roughness Ra of the surface 120U of the intermediate hardened layer 120 is small as described above. The lower limit of the arithmetic mean roughness Ra of the surface 120U of the intermediate hardened layer 120 is preferably 10 nm or more, more preferably 30 nm or more, and even more preferably 50 nm or more, from the viewpoint of increasing the adhesion between the insulating layer and the first conductor layer 130.

[0027] The arithmetic mean roughness Ra of the surface 120U of the intermediate hardened layer 120 on the first conductor layer side is obtained by measuring the arithmetic mean roughness Ra of the surface 120U before forming the first conductor layer 130. The arithmetic mean roughness Ra can be measured using a non-contact surface roughness meter. The specific measurement method can be the one described in the examples below.

[0028] The first conductor layer 130 is a layer containing a conductor material, and may contain only a conductor material. The conductor material preferably contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor material may be a single metal or an alloy. Examples of alloys include alloys of two or more metals selected from the above group (e.g., nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys). Among these, single metals of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloys of nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys are preferred from the viewpoint of versatility, cost, and ease of pattern processing. Furthermore, single metals of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or nickel-chromium alloys are even more preferred, and single metal copper is particularly preferred. The conductive material may be used alone or in combination of two or more types.

[0029] The first conductor layer 130 may have a single-layer structure, or it may have a multi-layer structure including two or more single-metal layers or alloy layers made of different types of metals or alloys. When the first conductor layer 130 has a multi-layer structure, the layer in contact with the intermediate hardened layer 120 is preferably a single-metal layer of chromium, zinc, or titanium, or an alloy layer of nickel-chromium alloy.

[0030] Since the first conductor layer 130 is formed to bond to the intermediate hardened layer 120, no other layers are usually formed between the intermediate hardened layer 120 and the first conductor layer 130. For example, when the first conductor layer 130 containing copper is formed by electroless plating of copper, catalyst residue may remain between the intermediate hardened layer 120 and the copper layer. In this case, since the catalyst can be understood as an element included in the first conductor layer 130, there are usually no other layers between the first conductor layer 130 formed by the electroless plating and the intermediate hardened layer 120.

[0031] The first conductor layer 130 may be formed on a portion of the surface 120U of the intermediate hardened layer 120, or it may be formed over the entire surface. Typically, the first conductor layer 130 is formed on a portion or the entire surface 120U of the circuit board that includes the location where a conductor layer (see conductor layer 160 in Figure 11) should be formed. In this embodiment, an example in which the first conductor layer 130 is formed over the entire surface 120U of the intermediate hardened layer 120 will be described.

[0032] There are no particular restrictions on the thickness of the first conductor layer 130, but it is preferable that it be thin from the viewpoint of facilitating the removal of the first conductor layer 130 in process (III) and from the viewpoint of making the circuit board thinner. The specific range of the thickness of the first conductor layer 130 is preferably 50 nm or more, more preferably 80 nm or more, even more preferably 100 nm or more, preferably 1000 nm or less, more preferably 800 nm or less, and even more preferably 500 nm or less. When the thickness of the first conductor layer 130 is within the above range, the manufacturing of the circuit board can be carried out smoothly.

[0033] A first example of a preferred method for manufacturing the intermediate laminate 100 is: Step (I-a1) of forming a resin composition layer on the inner layer substrate 110, The process of curing the resin composition layer to form an intermediate cured layer 120 (I-a2), and Step (I-a3) to form a first conductive layer 130 on the intermediate hardened layer 120, One possible method is to include these steps in this order. Therefore, it is preferable that step (I) includes steps (I-a1), (I-a2), and (I-a3) in this order. Below, a first example of a preferred method for manufacturing the intermediate laminate 100 will be described.

[0034] Figure 2 is a schematic cross-sectional view illustrating step (I-a1) in the manufacturing method of the intermediate laminate 100 according to the first example. As shown in Figure 2, the manufacturing method of the intermediate laminate 100 according to the first example includes step (I-a1) of forming a resin composition layer 121 on the inner layer substrate 110. The resin composition layer 121 is a layer containing a resin composition, and may contain only a resin composition. Typically, the thickness range of the resin composition layer 121 is the same as the thickness range of the intermediate cured layer 120.

[0035] The formation of the resin composition layer 121 on the inner layer substrate 110 in step (I-a1) may be carried out by a formation method that includes, for example, applying the resin composition to the inner layer substrate 110 and drying it as necessary. When using a liquid resin composition, the resin composition layer 121 can be formed by applying the resin composition to the inner layer substrate 110. Alternatively, a varnish-like resin composition may be obtained by mixing the non-volatile component of the resin composition with a solvent, and the varnish-like resin composition may be applied to the inner layer substrate 110 and further dried to form the resin composition layer 121. As the solvent, one of those described later in the section on resin compositions may be used.

[0036] The resin composition can be applied using a coating device such as a die coater. Drying can be carried out by drying methods such as heating or hot air blowing. The drying conditions are not particularly limited, but the solvent content in the resin composition layer 121 is usually 10% by mass or less, preferably 5% by mass or less. Although this may vary depending on the boiling point of the solvent, for example, when using a resin composition containing 30% to 60% by mass of solvent, the resin composition layer 121 can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0037] The formation of the resin composition layer 121 on the inner layer substrate 110 in step (I-a1) may be carried out using, for example, a resin sheet (not shown). The resin sheet comprises a support and a resin composition layer 121 formed on this support.

[0038] Examples of supports include plastic film, metal foil, and release paper, with plastic film and metal foil being preferred. When using a plastic film as the support, examples of plastic materials include polyester such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylic such as polymethyl methacrylate (PMMA), cyclic polyolefin, triacetylcellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, with inexpensive polyethylene terephthalate being particularly preferred. When using metal foil as the support, examples of metal foil include copper foil and aluminum foil, with copper foil being preferred. As for copper foil, foil made of single metal copper may be used, or foil made of an alloy of copper with other metals (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used.

[0039] The support may have surface treatments such as matte treatment, corona treatment, or antistatic treatment applied to the surface that is bonded to the resin composition layer. Alternatively, a support with a release layer may be used, which has a release layer on the surface that is bonded to the resin composition layer. 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-based release agents, polyolefin-based release agents, urethane-based release agents, and silicone-based release agents. Commercially available products may be used as the support with a release layer, for example, PET films having a release layer mainly composed of a silicone-based release agent or an alkyd resin-based release agent, such as "PET501010", "SK-1", "AL-5", and "AL-7" from Lintec Corporation; "Lumirror T60" from Toray Industries, Inc.; "Purex" from Teijin Ltd.; and "Unipeel" from Unitika Corporation.

[0040] The thickness of the support is not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, preferably 75 μm or less, more preferably 60 μm or less, and even more preferably 50 μm or less. When using a support with a release layer, it is preferable that the overall thickness of the support with the release layer is within the above range.

[0041] The resin sheet may include any components as needed. For example, the resin sheet may include a protective film to protect the resin composition layer. The protective film is usually provided on the side of the resin composition layer that is not bonded to the support (i.e., the side opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. When a protective film is provided, the adhesion of dust and scratches to the surface of the resin composition layer can be suppressed. Also, when the resin sheet has a protective film, the resin sheet can usually be used by removing the protective film.

[0042] A resin sheet can be manufactured, for example, by a method that includes forming a resin composition layer 121 on a support. Specifically, a resin sheet may be manufactured by applying a liquid or varnish-like resin composition onto a support and drying it as necessary to form a resin composition layer. The application and drying of the resin composition onto the support may be carried out in the same manner as the application and drying of the resin composition layer 121 onto the inner layer substrate 110.

[0043] A method for forming a resin composition layer 121 using a resin sheet typically involves laminating the resin sheet and an inner layer substrate 110. This lamination may be performed, for example, by heating and pressing the resin sheet onto the inner layer substrate 110 from the support side. Examples of a member used to heat and press the resin sheet onto the inner layer substrate 110 (hereinafter also referred to as the "heat-pressing member") include a heated metal plate (such as a SUS end plate) or a metal roll (such as a SUS roll). It is preferable to press the resin sheet via an elastic material such as heat-resistant rubber, rather than directly pressing the heat-pressing member onto the resin sheet, so that the resin sheet can adequately follow the surface irregularities of the inner layer substrate 110.

[0044] Lamination of the inner layer substrate 110 and the resin sheet may be carried out by a vacuum lamination method. In the heat-pressure bonding conditions of the vacuum lamination method, the heat-pressure bonding temperature is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C. The heat-pressure bonding pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably in the range of 0.29 MPa to 1.47 MPa. Furthermore, the heat-pressure bonding time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. Lamination is preferably carried out under reduced pressure conditions of 26.7 hPa or less.

[0045] Lamination may be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include vacuum pressure laminators manufactured by Meiki Seisakusho Co., Ltd., vacuum applicators manufactured by Nikko Materials Co., Ltd., and batch-type vacuum pressure laminators.

[0046] A method for forming a resin composition layer 121 using a resin sheet may include, after lamination, a smoothing treatment of the resin composition layer 121 by pressing a heat-pressure bonding member from the support side under normal pressure (atmospheric pressure). The pressing conditions for the smoothing treatment may be the same as the heat-pressure bonding conditions for lamination. The smoothing treatment can be performed using a commercially available laminator. Lamination and smoothing may be performed continuously using the commercially available vacuum laminator.

[0047] Figure 3 is a schematic cross-sectional view illustrating step (I-a2) in the manufacturing method of the intermediate laminate 100 according to the first example. As shown in Figure 3, the manufacturing method of the intermediate laminate 100 according to the first example includes step (I-a2), after step (I-a1), in which the resin composition layer 121 is subjected to a curing treatment to form an intermediate cured layer 120.

[0048] The curing treatment of the resin composition layer 121 is usually carried out by a thermosetting treatment. Heat causes the curable resins, such as (A) epoxy resin and (B) active ester resin contained in the resin composition layer, to react and form bonds. As a result, the curing of the resin composition layer progresses, and the intermediate cured layer 120 is formed. In step (I-a2), some of the curable resin contained in the resin composition layer may react, or all of it may react. Unreacted curable resin can be reacted by the heat treatment in the later step (IV), so usually in step (I-a2), only a portion of the curable resin (for example, 50% to 80% by mass of 100% by mass of curable resin) is reacted.

[0049] The conditions for the thermosetting treatment of the resin composition layer in step (I-a2) may vary depending on the type of resin composition. For example, the curing temperature is preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. The curing time may be preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 100 minutes.

[0050] Step (I-a2) may include a preheating treatment in which the resin composition layer 121 is preheated at a temperature lower than the curing temperature before the resin composition layer 121 is subjected to a preheating treatment at a temperature of usually 50°C to 150°C, preferably 60°C to 140°C, more preferably 70°C to 130°C, for usually 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, prior to the heat curing treatment of the resin composition layer 121.

[0051] When a resin sheet is used, the method for manufacturing the intermediate laminate 100 according to the first example may include a step of removing the resin sheet support after step (I-a1). The removal of the support may be performed before step (I-a2) or after step (I-a2). Furthermore, if the method for manufacturing the intermediate laminate 100 includes any steps such as a step of forming holes in the intermediate cured layer 120 (I-a5) and a step of roughening the intermediate cured layer 120 (I-a4), as described later, the removal of the support may be performed between steps (I-a2) and (I-a5), between steps (I-a5) and (I-a4), or after step (I-a4).

[0052] The method for manufacturing the intermediate laminate 100 according to the first example may include a step (I-a5) after step (I-a2) in which holes (not shown), such as via holes and through holes, are formed in the intermediate cured layer 120. The method for forming the holes can be selected according to factors such as the composition of the resin composition used to form the intermediate cured layer 120. For example, holes may be formed by processing methods such as drilling, laser processing, and plasma processing, with laser processing being preferred. For example, holes may be formed by irradiating the intermediate cured layer 120 with laser light after removing the support, or by irradiating the intermediate cured layer 120 with laser light through the support. The dimensions and shape of the holes may be appropriately determined according to the design of the circuit board.

[0053] The manufacturing method for the intermediate laminate 100 according to the first example may include a step (I-a4) of roughening the intermediate hardened layer 120. Step (I-a4) is usually performed between steps (I-a2) and (I-a3). The roughening treatment can roughen the surface 120U of the intermediate hardened layer 120. In addition, the roughening treatment can remove smear (resin residue) from the intermediate hardened layer 120. For this reason, this roughening treatment is sometimes called "desmear treatment". For example, if holes are formed in step (I-a5), smear may be formed inside those holes, so it is preferable to perform the roughening treatment in step (I-a4) after step (I-a5) to remove the smear.

[0054] The procedure and conditions for the roughening treatment are not particularly limited, and known procedures and conditions used when forming the insulating layer of a circuit board can be adopted. In this case, it is preferable to set the specific procedure and conditions so that the surface 120U of the intermediate hardened layer 120 after the roughening treatment has an arithmetic mean roughness Ra within the range described above. The roughening treatment may be carried out wet or dry.

[0055] Examples of wet roughening treatments include roughening treatments that involve applying swelling treatment with a swelling solution, oxidation treatment with an oxidizing agent, and neutralization treatment with a neutralizing solution to the intermediate hardened layer in that order.

[0056] Examples of swelling solutions used for roughening treatment include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Sodium hydroxide solution and potassium hydroxide solution are more preferred as the alkaline solution. Examples of commercially available swelling solutions include "Swelling Dip Securigant P" and "Swelling Dip Securigant SBU" manufactured by Atotec Japan. The swelling treatment with the swelling solution can be carried out, for example, by immersing the intermediate hardened layer 120 in a swelling solution at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing the swelling of the resin in the intermediate hardened layer 120 to an appropriate level, it is preferable to immerse the intermediate hardened layer 120 in a swelling solution at 40°C to 80°C for 5 to 15 minutes.

[0057] Examples of oxidizing agents used in the roughening treatment include alkaline permanganate solutions obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The oxidation treatment with an oxidizing agent such as an alkaline permanganate solution is preferably carried out by immersing the intermediate hardened layer 120 in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. Furthermore, the concentration of permanganate in the alkaline permanganate solution is preferably 5% to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigans P" manufactured by Atotec Japan.

[0058] An acidic aqueous solution is preferred as the neutralizing solution used for roughening treatment. A commercially available example is "Reduction Solution Securigant P" manufactured by Attec Japan. Neutralization treatment with the neutralizing solution can be performed by immersing the surface 120U that has been oxidized with an oxidizing agent in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the viewpoint of workability, it is preferable to immerse the object that has been oxidized with an oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

[0059] Dry roughening treatments include, for example, plasma-based roughening treatments. Plasma-based roughening treatments involve treating the intermediate hardened layer using plasma generated by introducing a gas into a plasma generator. Examples of plasmas include microwave plasma generated by microwaves, high-frequency plasma generated by high-frequency waves, atmospheric pressure plasma generated under atmospheric pressure, and vacuum plasma generated under vacuum, with vacuum plasma generated under vacuum being preferred.

[0060] The gas species (the gas species to be plasma-generated) is preferably a gas containing one or more selected from the group consisting of fluorine-based gases, N2, and O2. Unless otherwise specified, fluorine-based gases refer to gases containing fluorine atoms. Examples of fluorine-based gases include F2, CF4, C2F6, and SF6. The gas species may also include any gas such as Ar in combination with any of the fluorine-based gases, N2, and O2. In particular, from the viewpoint of improving smear removal performance, the gas species is more preferably a fluorine-based gas and O2. Furthermore, the gas species is even more preferably a mixed gas containing O2 and at least one of N2 and CF4. Among these, a mixed gas containing O2 and CF4 is particularly preferred.

[0061] When using a mixed gas containing one or more gases selected from the group consisting of N2 and O2, and other gases, the mixing ratio of "N2 and O2" to "gases other than N2 and O2" ("N2 and O2" / "gases other than N2 and O2") is preferably within a specific range from the viewpoint of improving smear removal performance. Specifically, the range of the mixing ratio is preferably 1 / 0.01 to 1 / 100, more preferably 1 / 0.5 to 1 / 10, and even more preferably 1 / 1 to 1 / 5. The unit of gas volume in the above mixing ratio is sccm. Unless otherwise specified, "sccm" is a unit of gas flow rate, and the amount of gas flowing per minute is expressed in terms of volume (cm³) when the gas is at 0°C and 1 atm. 3 This is shown by ).

[0062] The processing time for the plasma roughening treatment 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 such processing time is preferably 10 minutes or less, and more preferably 5 minutes or less, from the viewpoint of easily achieving an intermediate hardened layer with low surface roughness after the roughening treatment.

[0063] Plasma-based roughening treatment may be carried out using commercially available dry roughening equipment. Among commercially available dry roughening equipment, suitable examples for circuit board manufacturing include the plasma dry etching equipment from Oxford Instruments, the microwave plasma equipment from Nissin, and the atmospheric pressure plasma etching equipment from Sekisui Chemical Co., Ltd.

[0064] In step (I-a4), a wet roughening treatment may be performed in combination with another wet roughening treatment. Therefore, step (I-a4) may include a combination of applying a wet roughening treatment to the intermediate hardened layer and applying a wet roughening treatment to the intermediate hardened layer. In one example, step (I-a4) may include applying a dry roughening treatment to the intermediate hardened layer and then applying a wet roughening treatment to the intermediate hardened layer in that order.

[0065] The manufacturing method for the intermediate laminate 100 according to the first example includes a step (I-a3) of forming a first conductive layer 130 on the intermediate hardened layer 120 after step (I-a2). If the manufacturing method for the intermediate laminate 100 includes step (I-a4), step (I-a3) is usually performed after step (I-a4). Also, if the manufacturing method for the intermediate laminate 100 includes step (I-a5), step (I-a3) is usually performed after step (I-a5). By forming the first conductive layer 130, the intermediate laminate 100 shown in Figure 1 can be obtained.

[0066] There are no restrictions on the method for forming the first conductor layer 130. The first conductor layer 130 can be formed by, for example, a dry plating method or a wet plating method. 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. From the viewpoint of forming a thin and uniformly thick first conductor layer 130, sputtering and electroless plating are preferred, and electroless plating is more preferred.

[0067] Electroless plating typically involves attaching a catalyst to a surface 120U of an intermediate hardened layer 120, and bringing the catalyst-attached surface 120U into contact with an electroless plating solution to form a first conductive layer 130. Examples of catalysts include palladium, gold, silver, platinum, and rhodium, with palladium being preferred. Catalyst attachment can be carried out by methods such as vapor deposition, sputtering, or immersion, with immersion being preferred. In the immersion method, the surface 120U of the intermediate hardened layer 120 is immersed in a catalyst solution containing the catalyst. Furthermore, catalyst attachment by immersion may include optional treatments such as alkaline cleaning for washing the surface 120U, pre-dip treatment for adjusting the charge of the surface 120U, and reduction treatment for reducing the catalyst attached to the surface 120U with a reducing agent.

[0068] After the catalyst is attached to the surface 120U of the intermediate hardened layer 120, the surface 120U can be brought into contact with the electroless plating solution to form the first conductive layer 130. Contact between the surface 120U of the intermediate hardened layer 120 and the electroless plating solution may be performed, for example, by immersing the surface 120U in the electroless plating solution. Examples of electroless plating solutions include solutions containing metal ions such as copper, nickel, tungsten, tin, gold, and palladium, with solutions containing copper being preferred. The electroless plating solution may also contain optional additives such as reducing agents.

[0069] A second example of a preferred method for manufacturing the intermediate laminate 100 is: A resin sheet comprising a metal foil having a first conductive layer 130 and a resin composition layer 121 bonded to the first conductive layer 130 of the metal foil, and an inner layer substrate 110, a step (I-b1) of laminating the resin composition layer 121 and the inner layer substrate 110 so as to bond them together, Step (I-b2): A curing treatment is applied to the resin composition layer 121 to form an intermediate cured layer 120. One possible method is to include these steps in this order. Therefore, it is preferable that step (I) includes the above steps (I-b1) and (I-b2) in this order. Below, a second example of a preferred method for manufacturing the intermediate laminate 100 will be described. In the following description, in order to distinguish it from the resin sheet that can be used in the manufacturing method of the intermediate laminate 100 according to the first example, the resin sheet used in the manufacturing method of the intermediate laminate 100 according to the second example may be called a "metal-coated resin sheet". However, the resin sheet that can be used in the manufacturing method of the intermediate laminate 100 according to the first example and the metal-coated resin sheet used in the manufacturing method of the intermediate laminate 100 according to the second example may be the same.

[0070] Figure 4 is a schematic cross-sectional view showing a metal-coated resin sheet 200 used in a manufacturing method of an intermediate laminate 100 according to the second example. As shown in Figure 4, the metal-coated resin sheet 200 comprises a metal foil 210 having a first conductor layer 130 and a resin composition layer 121 bonded to the first conductor layer 130 of the metal foil 210. The metal foil 210 may optionally include a carrier metal foil layer 211. If the metal foil 210 includes a carrier metal foil layer 211, the metal-coated resin sheet 200 comprises the carrier metal foil layer 211, the first conductor layer 130, and the resin composition layer 121 in this order. The carrier metal foil layer 211 is usually provided so that it can be peeled off from the first conductor layer 130.

[0071] The resin composition layer 121 and the first conductor layer 130 are as described above. On the other hand, the carrier metal foil layer 211 contains a metal material, preferably only a metal material. The metal material may be a single metal or an alloy containing two or more metals. Examples of the metal material include those similar to the metal material that may be contained in the first conductor layer 130. The metal material contained in the carrier metal foil layer 211 may be the same as or different from the metal material contained in the first conductor layer 130.

[0072] The carrier metal foil layer 211 may have a single-layer structure comprising only one layer containing a single metal material, or it may have a multi-layer structure comprising multiple layers containing different types of materials. In particular, from the viewpoint of enabling smooth peeling from the first conductor layer 130, it is preferable that the carrier metal foil layer 211 has a multi-layer structure. More preferably, the carrier metal foil layer 211 comprises a support metal layer (not shown) containing the aforementioned metal material and a coating layer (not shown) that covers the surface of the support metal layer.

[0073] The support metal layer is formed of a metallic material. Therefore, the support metal layer contains a metallic material, and usually contains only a metallic material. The metallic material may be a single metal or an alloy containing two or more metals. Examples of metallic materials include those similar to the metallic material that may be contained in the first conductor layer 130. The metallic material contained in the support metal layer may be the same as or different from the metallic material contained in the first conductor layer 130. For example, the support metal layer may be an electrolytic metal foil, rolled metal foil, etc., formed from the aforementioned metallic material.

[0074] On the other hand, the coating layer is formed from a material different from the metallic material contained in the support metal layer. Preferably, the material of this coating layer is such that the carrier metal foil layer 211 can be smoothly peeled off from the first conductor layer 130. Specific examples of the coating layer material include organic materials and metallic materials different from the metallic material contained in the first conductor layer 130, with metallic materials different from the metallic material contained in the first conductor layer 130 being preferred. For example, if the first conductor layer 130 contains a metallic material including copper, preferred examples of the coating layer material include one or more selected from the group consisting of metals other than copper (e.g., nickel, aluminum, zinc, chromium, titanium, etc.), alloys containing metals other than copper (e.g., zinc alloy, chromium alloy, titanium alloy, nickel alloy, aluminum alloy, etc.), and compounds containing metals other than copper (e.g., chromate, zincate, etc.). Specific examples of the coating layer material include one or more selected from the group consisting of nickel, aluminum, zinc, chromate, and zinc alloy. Examples of zinc alloys include zinc-nickel alloys, zinc-nickel-phosphorus alloys, zinc-chromate alloys, and zinc-nickel-chromate alloys, with zinc-nickel alloys, zinc-chromate alloys, and zinc-nickel-chromate alloys being preferred.

[0075] From the viewpoint of improving handling, the thickness of the carrier metal foil layer 211 is preferably greater than the thickness of the first conductor layer 130. The specific thickness range of the carrier metal foil layer is preferably 5 μm or more, more preferably 10 μm or more, preferably 30 μm or less, and more preferably 20 μm or less.

[0076] The thickness of the metal foil 210 is preferably 1 μm or more, more preferably 1.5 μm or more, even more preferably 2 μm or more, preferably 35 μm or less, more preferably 25 μm or less, and even more preferably 18 μm or less.

[0077] Examples of methods for manufacturing the metal foil 210 include electrolysis, rolling, and vapor deposition. Alternatively, the metal foil may be manufactured by the method described in Japanese Patent Application Publication No. 2014-46600. Furthermore, commercially available metal foils may be used. Examples of commercially available metal foils include "Microcyn MT18Ex", "Microcyn MT18FL", "3EC-III", "3EC-M3-VLP", and "3EC-M2S-VLP" from Mitsui Mining & Smelting Co., Ltd.; "JDLC", "JTCSLC", "HA-V2", "HA", and "HG" from JX Metal Mining Co., Ltd.; and "CF-TX4-SV", "V9", "HD", "FLEQ HD", "FUTF", "RCF-T4X", and "RCF-T5B" from Fukuda Metal Foil & Powder Industry Co., Ltd.

[0078] The metal-coated resin sheet 200 may have any additional layer (not shown) in combination with the metal foil 210 and the resin composition layer 121. For example, the metal-coated resin sheet 200 may have a protective film as an additional layer on the side of the resin composition layer 121 that is not bonded to the metal foil 210 (i.e., the side opposite to the metal foil 210). The protective film may be the same as the protective film that the resin sheet may have in the manufacturing method of the intermediate laminate 100 according to the first example. If the metal-coated resin sheet 200 has a protective film, the metal-coated resin sheet 200 can usually be used by removing the protective film.

[0079] The metal-coated resin sheet 200 can be manufactured, for example, by a manufacturing method that includes the step of forming a resin composition layer 121 on a metal foil 210 so as to be bonded to the first conductor layer 130. Specifically, the metal-coated resin sheet 200 may be manufactured by a method that includes applying a liquid or varnish-like resin composition onto the metal foil 210 and drying it as necessary to form the resin composition layer 121. Another specific example is that the metal-coated resin sheet 200 may be manufactured by a method that includes laminating the resin sheet and the metal layer 210, as described in the manufacturing method of the intermediate laminate 100 according to the first example, such that the resin composition layer 121 and the first conductor layer 130 are bonded, and peeling off the support of the resin sheet as necessary.

[0080] Figure 5 is a schematic cross-sectional view illustrating step (I-b1) in the manufacturing method of the intermediate laminate 100 according to the second example. As shown in Figure 5, the manufacturing method of the intermediate laminate 100 according to the second example includes step (I-b1) of laminating the metal-coated resin sheet 200 and the inner layer substrate 110 such that the resin composition layer 121 and the inner layer substrate 110 are joined. The lamination of the metal-coated resin sheet 200 and the inner layer substrate 110 may be carried out in the same manner as the lamination of the resin sheet and the inner layer substrate 110 described in the manufacturing method of the intermediate laminate 100 according to the first example. Furthermore, step (I-b1) may include smoothing the resin composition layer 121 by pressing after lamination, similar to the lamination of the resin sheet and the inner layer substrate 110 described in the manufacturing method of the intermediate laminate 100 according to the first example.

[0081] Figure 6 is a schematic cross-sectional view illustrating step (I-b2) in the manufacturing method of the intermediate laminate 100 according to the second example. As shown in Figure 6, the manufacturing method of the intermediate laminate 100 according to the second example includes step (I-b2), after step (I-b1), in which the resin composition layer 121 is subjected to a curing treatment to form an intermediate cured layer 120. The curing treatment of the resin composition layer 121 in step (I-b2) may be carried out in the same manner as in step (I-a2) in the manufacturing method of the intermediate laminate 100 according to the first example.

[0082] Furthermore, step (I-b2) may include a preheating treatment in which the resin composition layer 121 is preheated at a temperature lower than the curing temperature before the resin composition layer 121 is subjected to a heat curing treatment. The conditions for the preheating treatment may be the same as the conditions for the preheating treatment in step (I-a2) in the manufacturing method of the intermediate laminate 100 according to the first example.

[0083] If the metal foil 210 includes a carrier metal foil layer 211, the method for manufacturing the intermediate laminate 100 may include a step (I-b3) of peeling off the carrier metal foil layer 211 after step (I-b1). It is preferable that this step (I-b3) is performed after step (I-b2). By peeling off the carrier metal foil layer 211, an intermediate laminate 100 with the first conductor layer 130 exposed can be obtained, as shown in Figure 1.

[0084] The method for manufacturing the intermediate laminate 100 according to the second example may further include any optional steps. For example, the method for manufacturing the intermediate laminate 100 may include a step (I-b4) of forming holes in the first conductive layer 130 and the intermediate hardened layer 120. Holes can be formed by processing methods such as drilling or laser processing.

[0085] <Process (II). Formation of the second conductive layer> Figure 7 is a schematic cross-sectional view illustrating step (II) according to one embodiment of the present invention. The method for manufacturing a circuit board according to this embodiment includes, after step (I) of preparing an intermediate laminate 100, step (II) of forming a second conductor layer 140 on a portion of the first conductor layer 130, as shown in Figure 7.

[0086] Typically, in step (II), the second conductor layer 140 is selectively formed on a portion of the first conductor layer 130 so that a second conductor layer 140 having a desired pattern shape is obtained. That is, in step (II), the second conductor layer 140 is formed not on the entire first conductor layer 130, but on a portion of the first conductor layer 130. Such a second conductor layer 140 can be formed, for example, by an electroplating method using the first conductor layer 130 as a plating seed layer. This method for forming the second conductor layer 140 by electroplating may include, in this order, the steps of forming a mask on the first conductor layer 130 (II-1), forming the second conductor layer 140 on the portion of the first conductor layer 130 not covered by the mask (II-2), and removing the mask (II-3).

[0087] Figure 8 is a schematic cross-sectional view illustrating step (II-1) of a method for manufacturing a circuit board according to one embodiment of the present invention. In step (II-1), as shown in Figure 8, a mask 310 is formed on the first conductor layer 130. The mask 310 is formed to expose a portion 131 of the first conductor layer 130 corresponding to the pattern shape of the second conductor layer 140 to be formed. That is, the mask 310 is formed to have a pattern shape that does not cover the portion 131 on which the second conductor layer 140 should be formed, but covers the other portion 132.

[0088] The mask 310 can be formed, for example, using a dry film. Specifically, a dry film can be laminated on the first conductive layer 130, and exposure and development using a photomask (not shown) can be performed in accordance with the pattern shape of the mask 310 to be formed to create the mask 310. As the dry film, for example, a photosensitive dry film formed from a photoresist composition can be used. Examples of photoresist compositions include novolac resin compositions and acrylic resin compositions. Commercially available dry films may be used, for example, "Photec RY-5115" from Resonaq Corporation and "ALPHO 20A263" from Nikko Materials Corporation can be used.

[0089] Figure 9 is a schematic cross-sectional view illustrating step (II-2) of a method for manufacturing a circuit board according to one embodiment of the present invention. After forming the mask 310 in step (II-1), step (II-2) is performed to form a second conductor layer 140 on the exposed first conductor layer 130 by electroplating, as shown in Figure 9. Specifically in step (II-2), the second conductor layer 140 is formed as an electroplated layer on the portion 131 of the first conductor layer 130 that is not covered by the mask 310.

[0090] In electroplating, the second conductive layer 140 is typically formed in an electroplating solution containing metal ions. For example, the first conductive layer 130 and an electrode (not shown) are placed in the electroplating solution, and a DC current is applied from a power source between the first conductive layer 130 and the electrode. Metal ions are reduced on the surface of the first conductive layer 130, causing metal to deposit, thus forming the second conductive layer 140 containing that metal.

[0091] Typically, an aqueous solution of a metal salt is used as the electroplating solution. The metal salt is not limited as long as it can form a second conductive layer 140 as the electroplating layer. For example, when copper is used as the metal, examples of copper salts include copper sulfate such as copper sulfate pentahydrate, copper halides such as copper chloride, copper acetate, copper nitrate, copper tetrafluoroborate, copper alkylsulfonate, copper arylsulfonate, copper sulfamate, copper perchlorate, and copper gluconate. Among these, copper sulfate is preferred. The electroplating solution may also contain additives such as acids (sulfuric acid, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, hydrochloric acid, etc.), halide ion suppliers, brighteners, and surfactants.

[0092] Step (II) typically includes step (II-3), which removes the mask 310 after step (II-2). Removal of the mask 310 yields the intermediate laminate 100 shown in Figure 7. There are no restrictions on the method of removing the mask 310. For example, a mask 310 formed from a dry film can be removed by contacting it with an appropriate stripping solution depending on the composition of the mask 310. In one example, the mask 310 can be removed using an alkaline stripping solution such as a sodium hydroxide solution.

[0093] <Process (IV). Heat Treatment> Figure 10 is a schematic cross-sectional view illustrating step (IV) according to one embodiment of the present invention. As shown in Figure 10, the method for manufacturing a circuit board according to this embodiment includes step (IV) of applying a heat treatment to the intermediate cured layer 120 to obtain an insulating layer 150. The heat treatment further advances the curing of the resin composition contained in the intermediate cured layer 120, so that an insulating layer 150 with excellent properties can be obtained. In addition, the heat treatment can usually improve the adhesion between the insulating layer 150 and the first conductor layer 130. This step (IV) is performed between step (I) and step (III). Therefore, step (IV) is performed after step (I) and before step (III). Such step (IV) may be performed before step (II), during step (II), or after step (II). Here, an example in which the heat treatment of step (IV) is performed after step (II) will be shown and explained.

[0094] The heating temperature range for the heat treatment in step (IV) is preferably 150°C or higher, more preferably 160°C or higher, even more preferably 170°C or higher, particularly preferably 180°C or higher, preferably 260°C or lower, more preferably 240°C or lower, and even more preferably 220°C or lower. The heating temperature in step (IV) may be constant or may vary within the above range. When the heating temperature is within the above range, the wiring lifting phenomenon can be effectively suppressed. In addition, the properties of the insulating layer 150, such as the mean linear thermal expansion coefficient and glass transition temperature, can usually be improved.

[0095] The heating time range for the heat treatment in step (IV) is preferably 20 minutes or more, more preferably 40 minutes or more, even more preferably 60 minutes or more, preferably 180 minutes or less, more preferably 150 minutes or less, and even more preferably 120 minutes or less. When the heating time is within the above range, the wiring lifting phenomenon can be effectively suppressed. In addition, the properties of the insulating layer 150, such as the mean linear thermal expansion coefficient and glass transition temperature, can usually be improved.

[0096] If the intermediate cured layer 120 prior to step (IV) contains unreacted components of the resin composition (e.g., unreacted thermosetting resin), the heat treatment may cause the reaction of these unreacted components to proceed. Therefore, the insulating layer 150 after the heat treatment in step (IV) may have different properties than the intermediate cured layer 120 prior to the heat treatment. Accordingly, the treatment conditions, such as the heating temperature and heating time, may be set so that the insulating layer 150 after the heat treatment exhibits the desired properties. For example, the insulating layer 150 included in the circuit board to be manufactured may have the same properties as the insulating layer 150 after the heat treatment, so the treatment conditions may be set according to the properties required for the insulating layer 150 of the circuit board. Conventionally, when manufacturing a circuit board equipped with an insulating layer 150 having desirable properties, wiring lifting phenomena could occur. However, according to the manufacturing method of this embodiment, it is possible to suppress wiring lifting phenomena even if the insulating layer 150 has desirable properties.

[0097] In one example, the mean linear thermal expansion coefficient CTE of the insulating layer 150 after step (IV) is preferably within a specific range. The specific range of such mean linear thermal expansion coefficient CTE is preferably 25 ppm / K or less, more preferably 22 ppm / K or less, and even more preferably 20 ppm / K or less. The lower limit may be, for example, 1 ppm / K or more, 5 ppm / K or more, 10 ppm / K or more, etc. Typically, the insulating layer 150 has a mean linear thermal expansion coefficient CTE within the above range before step (III), and may also have the same mean linear thermal expansion coefficient CTE in the circuit board after step (III). When the mean linear thermal expansion coefficient CTE of the insulating layer 150 is within the above range, warping of the circuit board can be effectively suppressed.

[0098] The average linear thermal expansion coefficient (CTE) of the insulating layer 150 can be measured as the average linear thermal expansion coefficient from 25°C to 150°C by performing thermomechanical analysis at a heating rate of 5°C / min from 25°C to 250°C. This thermomechanical analysis is performed twice, with the average linear thermal expansion coefficient (CTE) being measured in the second measurement. The specific measurement method can be the one described in the examples below.

[0099] In one example, a higher glass transition temperature Tg of the insulating layer 150 after step (IV) is preferable. The specific range of such glass transition temperature Tg is preferably 140°C or higher, more preferably 145°C or higher, and particularly preferably 150°C or higher. The upper limit may be, for example, 200°C or lower or 180°C or lower, and preferably 170°C or lower. Typically, the insulating layer 150 has a glass transition temperature Tg within the above range before step (III), and may also have the same glass transition temperature Tg in the circuit board after step (III). When the glass transition temperature Tg of the insulating layer 150 is within the above range, a circuit board with excellent heat resistance can be obtained.

[0100] The glass transition temperature Tg of the insulating layer 150 can be measured by thermomechanical analysis performed at a heating rate of 5°C / min from 25°C to 250°C. This thermomechanical analysis is performed twice, with the glass transition temperature Tg being measured in the second measurement. The specific measurement method can be the one described in the examples below.

[0101] In one example, the dielectric loss tangent Df of the insulating layer 150 after step (IV) is preferably as low as possible. The specific range of such dielectric loss tangent Df is preferably 0.005 or less, more preferably 0.004 or less, and particularly preferably 0.003 or less. The lower limit may be, for example, 0.0001 or more, and preferably 0.001 or more. Typically, the insulating layer 150 has a dielectric loss tangent Df within the above range before step (III), and may also have the same dielectric loss tangent Df in the circuit board after step (III). When the dielectric loss tangent Df of the insulating layer 150 is within the above range, the transmission loss of the circuit board can be effectively reduced.

[0102] The dielectric loss tangent of the insulating layer 150 can be measured by the cavity resonance perturbation method at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C. The specific measurement method can be the one described in the examples below.

[0103] <Step (III). Removal of unnecessary portions of the first conductor layer> In step (II) of forming the second conductor layer 140, as shown in Figures 7 and 10, the second conductor layer 140 is formed on portion 131 of the first conductor layer 130. The method for manufacturing a circuit board according to this embodiment includes, after step (II), step (III) of removing the first conductor layer 130 from portion 132 on which the second conductor layer 140 was not formed.

[0104] Figure 11 is a schematic cross-sectional view showing a circuit board 400 obtained in step (III) according to one embodiment of the present invention. The portion 132 (see Figure 9) of the first conductor layer 130 on which the second conductor layer 140 was not formed in step (II) corresponds to an unnecessary portion to be removed. Therefore, by removing the first conductor layer 130 in that portion 132, a conductor layer 160 can be formed as a layer including a combination of the first conductor layer 130 and the second conductor layer 140, as shown in Figure 11. Thus, a circuit board 400 can be obtained having an inner layer substrate 110, an insulating layer 150, and a conductor layer 160 in this order. Typically, the conductor layer 160 has the same pattern shape as the second conductor layer 140, so the conductor layer 160 can function as a wiring layer with a desired pattern shape.

[0105] The removal of the first conductor layer 130 from the portion 132 where the second conductor layer 140 was not formed can be performed, for example, using an etchant such as an etching solution. Specifically, when the material of the first conductor layer 130 is copper, examples of etching solutions include those mainly composed of hydrogen peroxide (hydrogen peroxide-based etching solution), acidic etching solutions, and alkaline etching solutions, with hydrogen peroxide-based etching solutions being preferred. Examples of commercially available hydrogen peroxide-based etching solutions include the SAC series etching solution manufactured by JCU Corporation. Examples of commercially available acidic etching solutions include "NH-1865" manufactured by MEC Corporation and "MelStrip N-950" manufactured by Meltex Corporation. Examples of commercially available alkaline etching solutions include "CF-6000" manufactured by MEC Corporation and "E-Process-WL" manufactured by Meltex Corporation. The removal of the first conductive layer 130 using an etching solution can be carried out, for example, by immersing the first conductive layer 130 in the etching solution or by spraying the etching solution onto the first conductive layer 130.

[0106] <Optional steps> The method for manufacturing the circuit board 400 according to this embodiment may include any additional steps in combination with the steps described above.

[0107] For example, the manufacturing method of the circuit board 400 may include a step (V) after step (III) in which an etching agent is brought into contact with the second conductor layer 140. The treatment in this step (V) corresponds to the CZ treatment described above. Contact with the etching agent creates minute irregularities on the surface of the second conductor layer 140. Typically, the etching agent comes into contact not only with the second conductor layer 140 but also with the first conductor layer 130, forming minute irregularities on the entire exposed surface of the conductor layer 160, including the first conductor layer 130 and the second conductor layer 140. These irregularities improve the adhesion between the conductor layer 160 and any insulating layer (not shown) that may be formed on the conductor layer 160. Furthermore, conventionally, contact with this etching agent caused wiring lifting in the conductor layer 160, but according to the manufacturing method of the circuit board 400 of this embodiment, it is possible to suppress this wiring lifting phenomenon.

[0108] As an etching agent, a liquid capable of forming minute irregularities on the surface of the second conductive layer 140 may be used. Examples of such etching agents include surface treatment agents that slightly dissolve the surface of the second conductive layer 140 and form a rough surface with fine irregularities. A specific example of such an etching agent is an acid solution. If the second conductive layer 140 contains copper, a sulfuric acid solution containing hydrogen peroxide and sulfuric acid may be used as an etching agent. An example of a commercially available etching agent is "CZ8201" manufactured by MEC.

[0109] The method for manufacturing the circuit board 400 may further include the steps of forming an arbitrary insulating layer on the conductive layer 160 and forming an arbitrary conductive layer on the arbitrary insulating layer, repeated once or two or more times. The arbitrary insulating layer may be formed, for example, in the same way as the insulating layer 150. The arbitrary conductive layer may also be formed, for example, in the same way as the conductive layer 160. A manufacturing method including the formation of multiple conductive layers and insulating layers makes it possible to manufacture a circuit board having a multilayer structure, such as a multilayer printed wiring board.

[0110] The method for manufacturing the circuit board 400 may include, for example, a step of providing a semiconductor chip (not shown) so as to be bonded to the conductor layer 160. For example, when manufacturing a circuit board 400 for a semiconductor chip package that includes a semiconductor chip, the method for manufacturing the circuit board 400 may include a step of providing the semiconductor chip. The semiconductor chip can employ appropriate conditions that allow the terminal electrodes of the semiconductor chip and the conductor layer 160 to be conductively connected. For example, conditions used in flip-chip mounting may be employed. The semiconductor chip may also be bonded via an insulating adhesive or by reflow soldering. Furthermore, if necessary, the provided semiconductor chip may be filled with mold underfill material. The method for manufacturing the circuit board 400 may also include, for example, a step of forming a sealing layer, a step of forming a solder resist layer, and a step of dicing the manufactured circuit board into individual pieces.

[0111] <Circuit boards to be manufactured> According to the manufacturing method described above, a circuit board 400 can be manufactured having an inner layer substrate 110, an insulating layer 150, and a conductor layer 160 in that order, as shown in Figure 11. In the manufactured circuit board 400, the phenomenon of wiring lifting is suppressed. Therefore, since the conductor layer 160 is prevented from separating from the insulating layer 150 and lifting up, a circuit board 400 can be obtained having a conductor layer 160 that is stably fixed to the surface 150U of the insulating layer 150.

[0112] The conductor layer 160 may have a linear pattern shape from the viewpoint of forming a wiring layer. Conventionally, the longer the wiring length, the more likely the wiring lifting phenomenon was to occur, but according to the manufacturing method described above, it is possible to suppress the wiring lifting phenomenon even when the wiring length is long. Therefore, from the viewpoint of utilizing this effect, a long wiring length is preferable. The aforementioned wiring length represents the length of the conductor layer 160, and therefore represents the length of the second conductor layer after step (III). Therefore, it is preferable that these lengths be long. Specifically, the range of the aforementioned lengths is preferably 10 mm or more, more preferably 13 mm or more, and even more preferably 15 mm or more. There is no particular upper limit, and it may be, for example, 10,000 mm or less.

[0113] The thickness of the conductor layer 160 can be set according to the design of the circuit board 400. In one example, the thickness of the conductor layer 160 is preferably 3 μm to 35 μm, more preferably 5 μm to 30 μm.

[0114] When the conductor layer 160 has a wiring-like pattern shape, the line range of the conductor layer 160 is preferably 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 1 μm or more, preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 15 μm or less. The space range of the conductor layer 160 is preferably 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 1 μm or more, preferably 50 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less. Furthermore, the wiring pitch range of the conductor layer is preferably 0.2 μm or more, more preferably 1 μm or more, even more preferably 2 μm or more, preferably 100 μm or less, more preferably 60 μm or less, and even more preferably 30 μm or less. Unless otherwise specified, "line" refers to the wiring width of the wiring formed by the conductor layer 160, and "space" refers to the spacing between wirings. The lines, spacing, and wiring pitch may be uniform or non-uniform throughout the conductor layer 160.

[0115] The insulating layer 150 includes a cured product of a resin composition containing a combination of (A) an epoxy resin and (B) an activated ester resin. Normally, polar groups such as hydroxyl groups are not generated by the reaction of (A) the epoxy resin and (B) the activated ester resin, so the resulting cured product can have low polarity. Therefore, the insulating layer 150 can have a low dielectric loss tangent Df. The range of the dielectric loss tangent Df of the insulating layer 150 provided on the circuit board 400 can be as described above. Conventionally, when the polarity of the cured product is low, the adhesion between the insulating layer and the conductor layer is generally low, and the wiring lifting phenomenon tends to occur. However, in the circuit board 400 manufactured by the manufacturing method according to this embodiment, both a low dielectric loss tangent Df and suppression of the wiring lifting phenomenon can be achieved.

[0116] In the manufacturing method described above, the curing reaction of the resin composition can be sufficiently advanced by heat treatment, so that the insulating layer 150 containing the cured product can have good properties. For example, the insulating layer 150 can have a good mean linear thermal expansion coefficient CTE and a glass transition temperature Tg. The range of the mean linear thermal expansion coefficient CTE and glass transition temperature Tg of the insulating layer 150 provided on the circuit board 400 may be as described above.

[0117] Examples of the circuit board 400 include printed circuit boards and semiconductor chip packages. Examples of semiconductor chip packages include FC-CSP, MIS-BGA packages, ETS-BGA packages, fan-out type WLP (Wafer Level Package), fan-in type WLP, fan-out type PLP (Panel Level Package), and fan-in type PLP. However, the circuit board 400 is not limited to those exemplified herein.

[0118] The circuit board 400 described above can be used in the manufacture of semiconductor devices. The semiconductor device comprises the circuit board 400 described above. Examples of semiconductor devices include various types of semiconductor devices used in electrical products (e.g., computers, mobile phones, smartphones, tablet devices, wearable devices, digital cameras, medical equipment, and televisions, etc.) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft, etc.).

[0119] <Resin composition> The resin composition used in the above-described method for manufacturing circuit boards will now be explained. The resin composition comprises (A) epoxy resin and (B) activated ester resin. The resin composition may also contain any additional components in combination with (A) epoxy resin and (B) activated ester resin.

[0120] ((A) Epoxy resin) (A) The epoxy resin has epoxy groups and can normally function as a curable resin. (A) The epoxy resin as component (A) may be used alone or in combination of two or more types.

[0121] (A) 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, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolac type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, phenol aralkyl type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiroring-containing epoxy resin, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, naphthylene ether type epoxy resin, trimethylol type epoxy resin, tetraphenylethane type epoxy resin, isocyanurate type epoxy resin, phenolphthaleimidine type epoxy resin, and the like. Biphenyl-type epoxy resins refer to epoxy resins having a biphenyl structure, where the biphenyl structure may have substituents such as alkyl groups, alkoxy groups, or aryl groups. Therefore, bixylenol-type epoxy resins and biphenylaralkyl-type epoxy resins can be included in the category of biphenyl-type epoxy resins.

[0122] (A) The epoxy resin preferably contains an epoxy resin containing an aromatic structure, from the viewpoint of obtaining an insulating layer with excellent heat resistance. An aromatic structure is a chemical structure generally defined as aromatic, and includes polycyclic aromatics and aromatic heterocyclics. Examples of epoxy resins containing aromatic structures include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolac type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, bisquilenol type epoxy resin, glycidylamine type epoxy resin having an aromatic structure, glycidyl ester type epoxy resin having an aromatic structure, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin having an aromatic structure, epoxy resin having a butadiene structure having an aromatic structure, alicyclic epoxy resin having an aromatic structure, heterocyclic epoxy resin, spiro-ring containing epoxy resin having an aromatic structure, cyclohexanedimethanol type epoxy resin having an aromatic structure, naphthylene ether type epoxy resin, trimethylol type epoxy resin having an aromatic structure, and tetraphenylethane type epoxy resin having an aromatic structure. Among these, bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, and biphenyl type epoxy resin are preferred. Naphthalene type epoxy resin refers to epoxy resin containing a naphthalene skeleton.

[0123] (A) The epoxy resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. (A) The proportion of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, relative to 100% by mass of the nonvolatile component of the epoxy resin.

[0124] (A) Epoxy resins include epoxy resins that are liquid at 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at 20°C (hereinafter sometimes referred to as "solid epoxy resins"). (A) Epoxy resins may contain only liquid epoxy resins, only solid epoxy resins, or a combination of liquid epoxy resins and solid epoxy resins.

[0125] 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, 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.

[0126] Specific examples of liquid epoxy resins include DIC's "HP-4032," "HP-4032-D," and "HP-4032-SS" (naphthalene-type epoxy resin); Mitsubishi Chemical's "828US," "828EL," "jER828EL," "825," and "Epicote 828EL" (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" (glycyrrhizol-type epoxy resin); and ADEKA's "EP-3950L" and "EP-398 Examples include "0S" (glycidylamine type epoxy resin); "EP-4088S" (dicyclopentadiene type epoxy resin) from ADEKA Corporation; "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) from Nippon Steel Chemical & Material Corporation; "EX-721" (glycidyl ester type epoxy resin) from Nagase ChemteX Corporation; "Celoxide 2021P" (alicyclic epoxy resin with an ester skeleton) from Daicel Corporation; "PB-3600" from Daicel Corporation; "JP-100" and "JP-200" (epoxy resins with a butadiene structure) from Nippon Soda Co., Ltd.; and "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin) from Nippon Steel Chemical & Material Corporation.

[0127] 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, 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, and phenolphthaleimidine-type epoxy resin are preferred.

[0128] 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-7311". "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin); "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "ESN475V", "ESN4 100V (naphthalene-type epoxy resin); "ESN485" (naphthol-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN375" (dihydroxynaphthalene-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YX4000HK", "YL7890" (bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL6121" (biphenyl-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "Y Examples include "X7700" (phenol aralkyl type epoxy resin); "PG-100" and "CG-500" from Osaka Gas Chemical Co., Ltd.; "YX7760" (bisphenol AF type epoxy resin) from Mitsubishi Chemical Corporation; "YL7800" (fluorene type epoxy resin) from Mitsubishi Chemical Corporation; "jER1010" (bisphenol A type epoxy resin) from Mitsubishi Chemical Corporation; "jER1031S" (tetraphenylethane type epoxy resin) from Mitsubishi Chemical Corporation; and "WHR991S" (phenolphthalein type epoxy resin) from Nippon Kayaku Co., Ltd.

[0129] (A) When the epoxy resin contains a combination of liquid epoxy resin and solid epoxy resin, the mass ratio of the liquid epoxy resin to the solid epoxy resin is preferably 20:1 to 1:20, more preferably 10:1 to 1:10, and particularly preferably 7:1 to 1:7.

[0130] (A) The epoxy equivalent range of the epoxy resin is preferably 50 g / eq. to 5,000 g / eq., more preferably 60 g / eq. to 3,000 g / eq., even more preferably 80 g / eq. to 2,000 g / eq., and particularly preferably 110 g / eq. to 1,000 g / eq. Epoxy equivalent represents the mass of resin per equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0131] (A) The weight-average molecular weight (Mw) of the epoxy resin is preferably in the range of 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight-average molecular weight can be measured as a polystyrene equivalent by gel permeation chromatography (GPC).

[0132] (A) The amount of epoxy resin is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on 100% by mass of the nonvolatile components in the resin composition. Unless otherwise specified, the nonvolatile components in the resin composition refer to the components of the resin composition excluding the (K) solvent.

[0133] (A) The amount of epoxy resin is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, even more preferably 30% by mass or more, preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, based on 100% by mass of the resin components in the resin composition. Unless otherwise specified, the resin components in the resin composition refer to the non-volatile components in the resin composition excluding (D) inorganic fillers.

[0134] ((B) Active ester resin) (B) The activated ester resin has an activated ester group and can normally function as a curable resin. (B) The activated ester resin as component (B) may be used alone or in combination of two or more types.

[0135] An active ester group refers to a group formed by an ester bond directly attached to an aromatic ring. This active ester group includes not only ester bonds contained in the aromatic carbon-C(=O)-O-aromatic carbon structure, but also ester bonds contained in the aliphatic carbon-C(=O)-O-aromatic carbon structure, insofar as they can react with an epoxy group to form a bond. Furthermore, the term "aromatic ring" refers to a ring that obeys Hückel's rule, where the number of electrons in the π-electron system on the ring is 4p+2 (where p is a natural number), and includes monocyclic aromatic rings and fused polycyclic aromatic rings formed by the fusion of two or more monocyclic aromatic rings. Aromatic rings can also be aromatic carbocyclic rings having only carbon atoms as ring constituent atoms, or aromatic heterocyclic rings having heteroatoms such as oxygen, nitrogen, or sulfur atoms in addition to carbon atoms as ring constituent atoms. Preferred aromatic rings are benzene rings, naphthalene rings, and anthracene rings, with benzene rings and naphthalene rings being particularly preferred. The term "aromatic carbon" refers to the carbon atoms that constitute the aromatic ring. (B) The number of active ester groups contained in one molecule of the active ester resin is usually one or more, preferably two or more.

[0136] (B) As the active ester resin, compounds having two or more highly reactive ester groups in one molecule are preferred, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds.

[0137] (B) The active ester resin 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. Particularly from the viewpoint of improving heat resistance, an active ester resin obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester resin obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, and the like. 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.

[0138] Specifically, (B) as the active ester resin, dicyclopentadiene-type active ester resins, naphthalene-type active ester resins containing a naphthalene structure, active ester resins containing an acetylated phenol novolac, and active ester resins containing a benzoylated phenol novolac are preferred; dicyclopentadiene-type active ester resins and naphthalene-type active ester resins are more preferred. As the dicyclopentadiene-type active ester resin, an active ester resin containing a dicyclopentadiene-type diphenol structure is preferred.

[0139] (B) Examples of commercially available active ester resins include, for example, active ester resins containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", "EXB-8000L-65M", "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000", "HPC-8000-65T", "EXB-8000H", "NE-V-1100-70T" (manufactured by DIC Corporation); and active ester resins containing a naphthalene structure such as "EXB-8100L-65T", "EXB-8150-60T", "EXB-8150-62T", "EXB Examples include "9411-65BK", "EXB-9416-70BK", "HPC-8150-62T", and "HPC-8151-62T" (manufactured by DIC Corporation); "EXB9401" (manufactured by DIC Corporation) as a phosphorus-containing active ester resin; "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin that is an acetylated phenol novolac; "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester resins that are benzoylated phenol novolacs; and "PC1300-02-65MA" (manufactured by Air Water Corporation) as an active ester resin containing a styryl group and a naphthalene structure.

[0140] (B) The range of the active ester group equivalent of the active ester resin is preferably 50 g / eq. or more, more preferably 100 g / eq. or more, preferably 3,000 g / eq. or less, more preferably 1,000 g / eq. or less, and even more preferably 500 g / eq. or less. The active ester group equivalent represents the mass of the resin per equivalent of one active ester group.

[0141] (B) The range of the weight-average molecular weight (Mw) of the active ester resin may be the same as the range of the weight-average molecular weight (Mw) of the epoxy resin (A).

[0142] The equivalent ratio of the active ester groups of the (B) active ester resin to the epoxy groups of the (A) epoxy resin is preferably within a specific range. Specifically, this equivalent ratio range is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less. The above equivalent ratio can be determined by dividing the number of active ester groups of the (B) active ester resin in the resin composition by the number of epoxy groups of the (A) epoxy resin in the resin composition. The "number of epoxy groups of the (A) epoxy resin" in the resin composition represents the sum of all values ​​obtained by dividing the mass of the nonvolatile components of the (A) epoxy resin present in the resin composition by their epoxy equivalents. The "number of active ester groups of the (B) active ester resin" in the resin composition represents the sum of all values ​​obtained by dividing the mass of the nonvolatile components of the (B) active ester resin present in the resin composition by their active ester group equivalents. Conventionally, when (A) epoxy resin and (B) activated ester resin were combined in the equivalent ratio within the aforementioned range, there was a tendency for wiring lifting to occur. In contrast, according to the manufacturing method of this embodiment, wiring lifting can be suppressed while combining (A) epoxy resin and (B) activated ester resin in the equivalent ratio that is prone to causing wiring lifting.

[0143] (B) The amount of the active ester resin is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 5% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on 100% by mass of the nonvolatile components in the resin composition.

[0144] (B) The amount of active ester resin is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, based on 100% by mass of the resin component in the resin composition.

[0145] The total amount of (A) epoxy resin and (B) active ester resin is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, even more preferably 60% by mass or more, preferably 99% by mass or less, more preferably 96% by mass or less, and even more preferably 94% by mass or less, based on 100% by mass of the resin component in the resin composition.

[0146] ((C) Any hardening agent) The resin composition may contain, as an optional component, (B) any curing agent other than an active ester resin. (C) Any curing agent as component (C) refers to a resin that can react with the epoxy resin to cure the resin composition. (C) Any curing agent does not include those corresponding to components (A) and (B) described above. (C) Any curing agent may be used alone or in combination of two or more types.

[0147] (C) Preferred examples of any curing agent include phenolic resins, carbodiimide resins, benzoxazine resins, cyanate ester resins, acid anhydride resins, amine resins, and thiol resins. Among these, phenolic resins and carbodiimide resins are preferred.

[0148] As phenolic resins, resins having one or more, preferably two or more, hydroxyl groups (phenolic hydroxyl groups) bonded to aromatic rings such as benzene rings and naphthalene rings per molecule can be used. From the viewpoint of heat resistance and water resistance, phenolic resins having a novolac structure are preferred. Furthermore, from the viewpoint of adhesion, nitrogen-containing phenolic resins are preferred, and triazine skeleton-containing phenolic resins are more preferred. Among these, triazine skeleton-containing phenol novolac resins are preferred from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion.

[0149] Specific examples of phenolic resins include "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", "SN-495V", and "SN-" from Nippon Steel Chemical & Material Co., Ltd. Examples include "375", "SN-395"; "TD-2090", "TD-2090-60M", "LA-7052", "LA-7054", "LA-1356", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", "TD-2090-60M" from DIC Corporation; and "GDP-6115L", "GDP-6115H", "ELPC75" from Gun-ei Chemical Co., Ltd.

[0150] As carbodiimide resins, resins having one or more, preferably two or more, carbodiimide structures in one molecule can be used. Specific examples of carbodiimide resins include aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexanebis(methylene-t-butylcarbodiimide); biscarbodiimides such as aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylenebiscyclohexylenecarbodiimide), and poly(isophoronecarbodiimide); and poly(phenylenecarbodiimide), poly(na Examples of polycarbodiimides include aromatic polycarbodiimides such as phthalenecarbodiimide, poly(tylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylenediphenylenecarbodiimide), and poly[methylenebis(methylphenylene)carbodiimide].

[0151] Examples of commercially available carbodiimide resins include "Carbodilite V-02B," "Carbodilite V-03," "Carbodilite V-04K," "Carbodilite V-05," "Carbodilite V-07," and "Carbodilite V-09" from Nisshinbo Chemical Co., Ltd., and "Stavaxol P," "Stavaxol P400," and "Hycazil 510" from Lanxess Corporation.

[0152] As the benzoxazine resin, a resin having one or more, preferably two or more, benzoxazine rings in one molecule can be used. Specific examples of benzoxazine resins include "JBZ-OP100D" and "ODA-BOZ" from JFE Chemical Corporation; "HFB2006M" from Showa Polymer Co., Ltd.; and "Pd," "Fa," and "ALP-d" from Shikoku Chemicals, Inc.

[0153] As the cyanate ester resin, a resin having one or more, preferably two or more cyanate groups in one molecule can be used. Examples of cyanate ester resins include bifunctional cyanate ester 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 ester resins derived from phenol novolacs and cresol novolacs; and prepolymers in which these cyanate ester resins are partially triazined. Specific examples of cyanate ester resins include "PT30" and "PT60" (phenol novolac type polyfunctional cyanate ester resins) manufactured by arxada, as well as "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate is triazined and trimerized).

[0154] As acid anhydride resins, resins having one or more, preferably two or more acid anhydride groups in one molecule can be used. Specific examples of acid anhydride resins 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 bensophenone tetracarboxylic acid di Examples 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 obtained by copolymerizing styrene and maleic acid. Examples of commercially available acid anhydride resins include "HNA-100," "MH-700," "MTA-15," "DDSA," and "OSA" from Shin Nippon Rika Co., Ltd.; "YH-306" and "YH-307" from Mitsubishi Chemical Corporation; "HN-2200" from Resonaq Corporation; and "EF-30," "EF-40," "EF-60," and "EF-80" from Clay Valley Corporation.

[0155] As the amine resin, a resin having one or more, preferably two or more, amino groups in one molecule can be used. Examples of amine resins include aliphatic amines, polyetheramines, alicyclic amines, aromatic amines, etc., with aromatic amines being preferred. The amine resin is preferably a primary amine or a secondary amine, with primary amines being more preferred. Specific examples of amine resins include 4,4'-methylenebis(2,6-dimethylaniline), 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-hydroxyphenyl)propyl Examples include pan, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, etc. Examples of commercially available amine resins include "SEIKACURE-S" from Seika Corporation; "KAYABOND C-200S," "KAYABOND C-100," "KAYAHARD AA," "KAYAHARD AB," and "KAYAHARD AS" from Nippon Kayaku Co., Ltd.; "Epicure W" from Mitsubishi Chemical Corporation; and "DTDA" from Sumitomo Seika Co., Ltd.

[0156] Examples of thiol-based resins include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris(3-mercaptopropyl) isocyanurate.

[0157] (C) The active group equivalent of any curing agent is preferably 50 g / eq. to 3,000 g / eq., more preferably 100 g / eq. to 1,000 g / eq., even more preferably 100 g / eq. to 500 g / eq., and particularly preferably 100 g / eq. to 300 g / eq. The active group equivalent represents the mass of resin per equivalent of active group. Furthermore, the active group of any curing agent (C) represents a group that can react with the epoxy group of the epoxy resin (A), such as a phenolic hydroxyl group.

[0158] (C) The range of the weight-average molecular weight (Mw) of any curing agent may be the same as the range of the weight-average molecular weight (Mw) of the epoxy resin (A).

[0159] (C) The amount of any curing agent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of the nonvolatile components in the resin composition.

[0160] (C) The amount of any curing agent is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, based on 100% by mass of the resin components in the resin composition.

[0161] (C) The number of active groups of any curing agent is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.1 or more, preferably 2 or less, more preferably 1 or less, and even more preferably 0.5 or less, when the number of epoxy groups of (A) epoxy resin is set to 1. The "(C) number of active groups of any curing agent" in the resin composition refers to the sum of all values ​​obtained by dividing the mass of the nonvolatile components of (C) any curing agent present in the resin composition by the equivalent amount of its active groups.

[0162] ((D) Inorganic filler) The resin composition may contain (D) an inorganic filler as an optional component. The (D) inorganic filler, as a component, is a particle of inorganic material. Therefore, the (D) inorganic filler is included in the resin composition in granular form and is usually included in the cured product while maintaining that granular state.

[0163] (D) Inorganic materials are typically inorganic compounds used to form the inorganic filler. (D) Examples of materials for the inorganic filler 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 and alumina are preferred, and silica is particularly preferred. Therefore, (D) the inorganic filler preferably contains silica, and may contain only silica. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Furthermore, spherical silica is preferred as the silica. (D) The inorganic filler may be used alone or in combination of two or more types.

[0164] (D) Examples of commercially available inorganic fillers include "SP60-05" and "SP507-05" from Nippon Steel Chemical & Material Co., Ltd.; "YC100C", "YA050C", "YA050C-MJE", "YA010C", "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" 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; and "Cellspheres" and "MGH-005" from Taiheiyo Cement Corporation.

[0165] (D) The average particle size of the inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less, and even more preferably 1 μm or less.

[0166] (D) 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 prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing them with ultrasound for 10 minutes. The sample can be measured using a laser diffraction-type particle size distribution analyzer with blue and red light source wavelengths, using a flow cell method to measure the volume-based particle size distribution of the inorganic filler, and the average particle size can be calculated as the median diameter from the obtained particle size distribution. An example of a laser diffraction-type particle size distribution analyzer is the "LA-960" manufactured by Horiba, Ltd.

[0167] (D) The specific surface area of ​​the inorganic filler is preferably 0.1 m². 2 / g or more, more preferably 0.5m 2 / g or more, more preferably 1m 2 / g or more, particularly preferably 3m 2 It is 100m or more / g, preferably 100m 2 / g or less, more preferably 70 m 2 / g or less, still more preferably 50 m 2 / g or less, particularly preferably 40 m 2 / g or less. (D) The specific surface area of the inorganic filler can be measured by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) in accordance with the BET method and calculating the specific surface area using the BET multipoint method.

[0168] (D) The inorganic filler is preferably treated with a surface treatment agent from the viewpoints of enhancing moisture resistance and dispersibility. Examples of the surface treatment agent include fluorine-containing silane coupling agents, aminosilane-based coupling agents, epoxysilane-based coupling agents, mercaptosilane-based coupling agents, silane-based coupling agents, alkoxysilanes, organosilazane compounds, titanate-based coupling agents, and the like. The surface treatment agent may be used alone or in any combination of two or more kinds.

[0169] Examples of commercially available products of the surface treatment agent include "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM803" (3-mercaptopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBE903" (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "SZ-31" (hexamethyldisilazane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM103" (phenyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM-4803" (long-chain epoxy type silane coupling agent) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., and the like.

[0170] 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 specific range. Specifically, 100% by mass of the inorganic filler is preferably surface-treated with 0.2% to 5% by mass of the surface treatment agent, more preferably with 0.2% to 3% by mass of the surface treatment agent, and even more preferably with 0.3% to 2% by mass of the surface treatment agent.

[0171] 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 / m 2 The following is preferred: 0.8 mg / m² 2 The following is more preferable: 0.5 mg / m² 2 The following are even more preferable.

[0172] (D) The amount of carbon per unit surface area of ​​the inorganic filler can be measured after cleaning 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, a Horiba "EMIA-320V" or similar can be used.

[0173] (D) The amount of inorganic filler is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, based on 100% by mass of the nonvolatile components in the resin composition.

[0174] ((E) Thermoplastic resin) The resin composition may contain (E) a thermoplastic resin as an optional component. The (E) thermoplastic resin as component (E) does not include those corresponding to components (A) to (D) described above. The (E) thermoplastic resin is usually included in the resin composition in a compatible state with curable resins such as (A) epoxy resin, (B) active ester resin, and (C) any curing agent, and is included in the cured product in that compatible state. The (E) thermoplastic resin may be used alone or in combination of two or more types.

[0175] (E) Thermoplastic resins typically have a large molecular weight. Specifically, the weight-average molecular weight Mw of (E) thermoplastic resins is preferably greater than 5,000, more preferably 8,000 or more, even more preferably 10,000 or more, even more preferably 20,000 or more, preferably 100,000 or less, more preferably 70,000 or less, even more preferably 60,000 or less, and even more preferably 50,000 or less. The weight-average molecular weight Mw can be measured in polystyrene equivalent values ​​by gel permeation chromatography (GPC).

[0176] (E) Examples of thermoplastic resins include phenoxy resin, polyimide resin, polyvinyl acetal resin, polystyrene resin, polyolefin resin, polybutadiene resin, polyamide-imide resin, polyethersulfone resin, polysulfone resin, polyetherimide resin, polyphenylene ether resin, polycarbonate resin, polyetheretherketone resin, polyester resin, etc. Among these, phenoxy resin is preferred.

[0177] Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton. The ends of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Specific examples of phenoxy resins include "1256" and "4250" (both phenoxy resins containing the bisphenol A skeleton) manufactured by Mitsubishi Chemical Corporation; "YX8100" (phenoxy resin containing the bisphenol S skeleton) manufactured by Mitsubishi Chemical Corporation; "YX7800BH40" (phenoxy resin containing the fluorene skeleton) manufactured by Mitsubishi Chemical Corporation; and "YX6954" (phenoxy resin containing the bisphenolacetophenone skeleton) manufactured by Mitsubishi Chemical Corporation. Examples include: "FX280" and "FX293" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YL7500BH30", "YL6954BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30", "YL6794", "YL7213", "YL7290", "YL7482", "YL7891BH30", and "YL7891T30" manufactured by Mitsubishi Chemical Corporation.

[0178] Specific examples of polyimide resins include "PIAD200" manufactured by Arakawa Chemical Co., Ltd., "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., and "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin-Nippon Rika Co., Ltd. Other specific examples of polyimide resins include linear polyimide resins obtained by reacting a bifunctional hydroxyl-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride (polyimide resin described in Japanese Patent Publication No. 2006-37083), and modified polyimide resins containing a polysiloxane skeleton (polyimide resins described in Japanese Patent Publication No. 2002-12667 and Japanese Patent Publication No. 2000-319386, etc.).

[0179] Examples of polyvinyl acetal resins include polyvinyl formal resin and polyvinyl butyral resin, with polyvinyl butyral resin being preferred. Specific examples of polyvinyl acetal resins include S-Rec BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, BM series, etc., manufactured by Sekisui Chemical Co., Ltd.

[0180] Examples of polystyrene resins include unmodified polystyrene resin, oxazoline group-containing modified polystyrene resin, and styrene block copolymer. Examples of styrene block copolymers include styrene-isoprene-styrene block copolymer (SIS resin), styrene-ethylene-butylene-styrene block copolymer (SEBS resin), styrene-ethylene-propylene-styrene block copolymer (SEPS resin), styrene-butadiene-styrene block copolymer (SBS resin), and styrene-isobutylene-styrene block copolymer (SIBS resin). Specific examples of polystyrene resins include "PX3-RP-37" and "RP-RX-61" (oxazoline group-containing modified polystyrene resin) from Nippon Shokubai Co., Ltd.; and "HYBRAR" from Kuraray Co., Ltd. 5125 (SIS resin); Asahi Kasei's "S1611" (SEBS resin); Asahi Kasei's "H1041", "ToughTec H1043", "ToughTec P2000", "ToughTec MP10" (hydrogenated styrene thermoplastic resin); Daicel's "Epofriend AT501", "CT310" (epoxidized styrene-butadiene thermoplastic resin); Kuraray's "Septon HG252" (modified polystyrene resin with hydroxyl groups); Asahi Kasei's "ToughTec N503M" (modified polystyrene resin with carboxyl groups); Asahi Kasei's "ToughTec N501" (modified polystyrene resin with amino groups); Asahi Kasei's "ToughTec M1913" (modified polystyrene resin with acid anhydride groups); Kuraray's "Septon S8104" (unmodified polystyrene resin); Kraton's "FG1924" (styrene-ethylene / butylene-styrene block copolymer); "EF-40" (CRAY Examples include products manufactured by VALLEY Corporation.

[0181] Examples of polyolefin resins include ethylene-based copolymer resins such as low-density polyethylene, ultra-low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer; and polyolefin polymers such as polypropylene and ethylene-propylene block copolymer.

[0182] Examples of polybutadiene resins include hydrogenated polybutadiene skeleton-containing resins, hydroxyl group-containing polybutadiene resins, phenolic hydroxyl group-containing polybutadiene resins, carboxyl group-containing polybutadiene resins, acid anhydride group-containing polybutadiene resins, epoxy group-containing polybutadiene resins, isocyanate group-containing polybutadiene resins, urethane group-containing polybutadiene resins, and polyphenylene ether-polybutadiene resins.

[0183] Specific examples of polyamide-imide resins include "Viromax HR11NN" and "Viromax HR16NN" manufactured by Toyobo Co., Ltd. Other specific examples of polyamide-imide resins include modified polyamide-imides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamide-imide) manufactured by Hitachi Chemical Co., Ltd.

[0184] Specific examples of polyethersulfone resins include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

[0185] Specific examples of polysulfone resins include Solvay Advanced Polymers' polysulfones "P1700" and "P3500".

[0186] The polyphenylene ether resin may be, for example, a copolymer of polyphenylene ether and polybutadiene.

[0187] Specific examples of polyetherimide resins include GE's "Ultem," among others.

[0188] Examples of polycarbonate resins include hydroxyl group-containing carbonate resins, phenolic hydroxyl group-containing carbonate resins, carboxyl group-containing carbonate resins, acid anhydride group-containing carbonate resins, isocyanate group-containing carbonate resins, and urethane group-containing carbonate resins. Specific examples of polycarbonate resins include "FPC0220" from Mitsubishi Gas Chemical Co., Ltd., "T6002" and "T6001" (polycarbonate diols) from Asahi Kasei Corporation, and "C-1090," "C-2090," and "C-3090" (polycarbonate diols) from Kuraray Co., Ltd.

[0189] Specific examples of polyether ether ketone resins include "Sumiproi K" manufactured by Sumitomo Chemical Co., Ltd.

[0190] Examples of polyester resins include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, and polycyclohexanedimethyl terephthalate resin.

[0191] (E) The amount of thermoplastic resin is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition.

[0192] (E) The range of the amount of thermoplastic resin is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, preferably 20% by mass or less, preferably 15% by mass or less, and more preferably 10% by mass or less, based on 100% by mass of the resin component of the resin composition.

[0193] ((F)Organic filler) The resin composition may contain (F) an organic filler as an optional component. The (F) organic filler as component (F) does not include those corresponding to components (A) to (E) described above. The (F) organic filler is usually miscible with curable resins such as (A) epoxy resin, (B) active ester resin, and (C) any curing agent, and is included in the resin composition in granular form, and is included in the cured product while maintaining that granular form. The (F) organic filler may be used alone or in combination of two or more types.

[0194] (F) As the organic filler, particles of organic material may be used. (F) As the organic material contained in the organic filler, rubber components are preferred. Examples of rubber components 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, ethylene-propylene-butene terpolymer; and thermoplastic elastomers such as acrylic-based thermoplastic elastomers such as propyl poly(meth)acrylate, butyl poly(meth)acrylate, cyclohexyl poly(meth)acrylate, and octyl poly(meth)acrylate. Furthermore, silicone-based rubbers such as polyorganosiloxane rubber may be mixed with the rubber component. The rubber component contained in the rubber particles has a glass transition temperature of, for example, 0°C or lower, preferably -10°C or lower, more preferably -20°C or lower, and even more preferably -30°C or lower.

[0195] (F) The organic filler may be a core-shell type rubber particle consisting of a core particle 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 particle. Here, "core-shell type" does not necessarily refer only to those in which the core particle and the shell portion can be clearly distinguished, but also includes those in which the boundary between the core particle and the shell portion is unclear, and the core particle does not have to be completely covered by the shell portion.

[0196] (F)Specific examples of organic fillers include, for example, "CHT" from Samsung SDI; "B602" from Techno UMG; "Paraloid EXL-2602", "Paraloid EXL-2603", "Paraloid EXL-2655", "Paraloid EXL-2311", "Paraloid-EXL2313", "Paraloid EXL-2315", "Paraloid KM-330", "Paraloid KM-336P", "Paraloid KCZ-201" from Dow Corporation; and "Metablen C-223A", "Metablen E-" from Mitsubishi Rayon Corporation. Examples include "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 Kogyo Co., Ltd.'s "Stafiloid AC3355", "Stafiloid AC3816", "Stafiloid AC3816N", "Stafiloid AC3832", "Stafiloid AC4030", and "Stafiloid AC3364".

[0197] (F) The amount of organic filler is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition.

[0198] (F) The amount of organic filler is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of the resin component of the resin composition.

[0199] ((G) Curing accelerator) The resin composition may contain (G) a curing accelerator as an optional component. The curing accelerator as component (G) does not include any of the components (A) to (F) described above. The curing accelerator (G) can act as a catalyst in the reaction of the epoxy resin (A) to accelerate the curing of the resin composition.

[0200] (G) Examples of curing accelerators include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, amine-based curing accelerators, etc. (G) A single type of curing accelerator may be used, or two or more types may be used in combination.

[0201] Examples of phosphorus-based curing accelerators include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium) pyromelitate, tetrabutylphosphonium hydrogen hexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butyldimethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, and tetraphenylphosphonium bromide. Aromatic phosphonium salts such as tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone addition products such as triphenylphosphine-p-benzoquinone addition products; aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine;Dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine Examples include aromatic phosphines such as tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, and 2,2'-bis(diphenylphosphino)diphenyl ether.

[0202] Examples of urea-based curing accelerators include aliphatic dimethylureas such as 1,1-dimethylurea, 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. Aromatic dimethylureas such as toluenebisdimethylurea, 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N',N'-dimethylurea), and N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluenebisdimethylurea] are examples.

[0203] Examples of guanidine-based curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]deca-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]deca-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

[0204] Examples of imidazole-based curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-methylimidazole. Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanurate adduct, 2-phenylimidazole isocyanurate adduct, Examples of imidazole compounds include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline; and adducts of imidazole compounds with epoxy resins. Examples of commercially available imidazole-based curing accelerators include "1B2PZ", "2E4MZ", "2MZA-PW", "2MZ-OK", "2MA-OK", "2MA-OK-PW", "2PHZ", "2PHZ-PW", "Cl1Z", "Cl1Z-CN", "Cl1Z-CNS", and "C11Z-A" from Shikoku Chemicals, Inc.; and "P200-H50" from Mitsubishi Chemical Corporation.

[0205] Examples of metal-based hardening accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organocobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organocopper complexes such as copper(II) acetylacetonate, organozinc complexes such as zinc(II) acetylacetonate, organoiron complexes such as iron(III) acetylacetonate, organonickel complexes such as nickel(II) acetylacetonate, and organomanganese complexes such as manganese(II) acetylacetonate. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0206] Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene. Commercially available amine-based curing accelerators may also be used, such as "MY-25" manufactured by Ajinomoto Fine Techno Co., Ltd.

[0207] (G) The amount of curing accelerator is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less, based on 100% by mass of the nonvolatile components in the resin composition.

[0208] (G) The amount of curing accelerator is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, preferably 10% by mass or less, more preferably 6% by mass or less, and even more preferably 3% by mass or less, based on 100% by mass of the resin component in the resin composition.

[0209] ((H) radical polymerizable resin) The resin composition may contain (H) radical polymerizable resin as an optional component. The (H) radical polymerizable resin as component (H) does not include those corresponding to components (A) to (G) described above. The (H) radical polymerizable resin may be used alone or in combination of two or more types.

[0210] (H) Radical polymerizable resins can include resins containing non-aromatic carbon-carbon unsaturated bonds. Therefore, (H) radical polymerizable resins can usually have polymerizable unsaturated groups containing non-aromatic carbon-carbon unsaturated bonds. Examples of polymerizable unsaturated groups include unsaturated hydrocarbon groups such as vinyl groups, allyl groups, 1-propenyl groups, 3-cyclohexenyl groups, 3-cyclopentenyl groups, 2-vinylphenyl groups, 3-vinylphenyl groups, and 4-vinylphenyl groups; and α,β-unsaturated carbonyl groups such as acryloyl groups, methacryloyl groups, and maleimide groups (2,5-dihydro-2,5-dioxo-1H-pyrrole-1-yl groups). (H) It is preferable that radical polymerizable resins have two or more polymerizable unsaturated groups in one molecule.

[0211] (H) Examples of radical polymerizable resins include (meth)acrylic radical polymerizable resins, styrene radical polymerizable resins, allyl radical polymerizable resins, and maleimide radical polymerizable resins.

[0212] As (meth)acrylic radical polymerizable resins, resins having one or more, preferably two or more acryloyl groups and / or methacryloyl groups per molecule can be used. Examples of (meth)acrylic radical polymerizable resins include cyclohexane-1,4-dimethanol di(meth)acrylate, cyclohexane-1,3-dimethanol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, and 1,9-nonane. Low molecular weight (molecular weight less than 1000) aliphatic (meth)acrylic acid ester compounds such as diol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, glycerin tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate; dioxaneglycol di(meth)acrylate, 3,6-dioxa-1,8-octanediol di(meth)acrylate; Examples include low molecular weight (molecular weight less than 1000) ether-containing (meth)acrylic acid ester compounds such as acrylate, 3,6,9-trioxaundecane-1,11-diol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, ethoxylated bisphenol A di(meth)acrylate, and propoxylated bisphenol A di(meth)acrylate; low molecular weight (molecular weight less than 1000) isocyanurate-containing (meth)acrylic acid ester compounds such as tris(3-hydroxypropyl) isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl) isocyanurate tri(meth)acrylate, and ethoxylated isocyanurate tri(meth)acrylate; and high molecular weight (molecular weight 1000 or more) acrylic acid ester compounds such as (meth)acrylic-modified polyphenylene ether resins. Here, the term "(meth)acrylic acid" includes acrylic acid, methacrylic acid, and combinations thereof.Furthermore, the term "(meth)acrylate" encompasses acrylate, methacrylate, and combinations thereof. Examples of commercially available (meth)acrylic radical polymerizable resins include "A-DOG" (dioxane glycol diacrylate) from Shin Nakamura Chemical Industry Co., Ltd., "DCP-A" (tricyclodecane dimethanol diacrylate), "DCP" (tricyclodecane dimethanol dimethacrylate), and "BPE-1300N" (ethoxylated bisphenol A dimethacrylate) from Kyoeisha Chemical Co., Ltd., "KAYARAD R-684" (tricyclodecane dimethanol diacrylate) and "KAYARAD R-604" (dioxane glycol diacrylate) from Nippon Kayaku Co., Ltd., and "SA9000" and "SA9000-111" (methacrylic modified polyphenylene ether) from SABIC Corporation.

[0213] As styrene-based radical polymerizable resins, resins having one or more, preferably two or more, vinyl groups directly bonded to aromatic carbon atoms in one molecule can be used. Examples of styrene-based radical polymerizable resins include low molecular weight (molecular weight less than 1000) styrene compounds such as divinylbenzene, 2,4-divinyltoluene, 2,6-divinylnaphthalene, 1,4-divinylnaphthalene, 4,4'-divinylbiphenyl, 1,2-bis(4-vinylphenyl)ethane, 2,2-bis(4-vinylphenyl)propane, and bis(4-vinylphenyl) ether; and high molecular weight (molecular weight 1000 or more) styrene compounds such as vinylbenzyl-modified polyphenylene ether resins and styrene-divinylbenzene copolymers. Examples of commercially available styrene-based radical polymerizable resins include "ODV-XET(X03)", "ODV-XET(X04)", and "ODV-XET(X05)" (styrene-divinylbenzene copolymer) from Nippon Steel Chemical & Material Co., Ltd., and "OPE-2St 1200" and "OPE-2St 2200" (vinylbenzyl-modified polyphenylene ether resin) from Mitsubishi Gas Chemical Co., Ltd.

[0214] As the allyl-based radical polymerizable resin, a resin having one or more, preferably two or more allyl groups per molecule can be used. Examples of allyl-based radical polymerizable resins include aromatic carboxylic acid allyl ester compounds such as diallyl diphenate, triallyl trimellitate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl 2,6-naphthalenedicarboxylic acid, and diallyl 2,3-naphthalenecarboxylic acid; isocyanurate allyl ester compounds such as 1,3,5-trialyl isocyanurate and 1,3-diallyl-5-glycidyl isocyanurate; ether-containing aromatic allyl compounds such as 1,3,5-trialyl etherbenzene; and allyl silane compounds such as diallyldiphenylsilane. Examples of commercially available allyl-based radical polymerizable resins include "TAIC" (1,3,5-triallyl isocyanurate) from Nippon Chemical Industries, Ltd., "DAD" (diallyl diphenate) from Nichishoku Techno Fine Chemicals Co., Ltd., "TRIAM-705" (triallyl trimellitate) from Fujifilm Wako Pure Chemical Corporation, "DAND" (2,3-diallyl naphthalenecarboxylate) from Nichishoku Techno Fine Chemicals Co., Ltd., and "ALP-d" (bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazine-3-yl)phenyl]methane) from Shikoku Chemicals, Ltd.

[0215] As the maleimide-based radical polymerizable resin, a resin having one or more, preferably two or more, maleimide groups per molecule can be used. The maleimide-based radical polymerizable resin may be an aromatic maleimide resin having maleimide groups directly bonded to an aromatic ring, or it may be an aliphatic maleimide resin not having maleimide groups directly bonded to an aromatic ring. Examples of commercially available maleimide-based radical polymerizable resins include "SLK-2600" from Shin-Etsu Chemical Co., Ltd., "BMI-1500", "BMI-1700", "BMI-3000J", "BMI-689", and "BMI-2500" (dimer amine structure-containing maleimide compounds) from Designer Molecules Inc., "BMI-6100" (aromatic maleimide compound) from Designer Molecules Inc., "MIR-5000", "MIR-5000-60T", and "MIR-3000-70MT" (biphenyl aralkyl type maleimide compounds) from Nippon Kayaku Co., Ltd., "BMI-70" and "BMI-80" from K.I. Chemicals Co., Ltd., and "BMI-2300", "BMI-3000", and "BMI-TMH" from Yamato Chemical Industries, Ltd. Furthermore, as a maleimide-based radical polymerizable resin, a maleimide resin (indane ring skeleton-containing maleimide compound) disclosed in the Japan Institute of Invention and Innovation Publication No. 2020-500211 may be used.

[0216] (H) The polymerizable unsaturated group equivalent of the radical polymerizable resin is preferably 20 g / eq. to 3,000 g / eq., more preferably 50 g / eq. to 2,500 g / eq., even more preferably 70 g / eq. to 2,000 g / eq., and particularly preferably 90 g / eq. to 1,500 g / eq. The polymerizable unsaturated group equivalent represents the mass of the resin per equivalent of polymerizable unsaturated groups.

[0217] (H) The weight-average molecular weight (Mw) of the radical polymerizable resin is preferably 40,000 or less, more preferably 10,000 or less, even more preferably 5,000 or less, and particularly preferably 3,000 or less. The lower limit is not particularly limited, but may be, for example, 150 or more.

[0218] (H) The range of the amount of radical polymerizable resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition.

[0219] (H) The range of the amount of radical polymerizable resin is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on 100% by mass of the resin component of the resin composition.

[0220] ((I) Polymerization initiator) The resin composition may contain (I) a polymerization initiator as an optional component. The (I) polymerization initiator as component (I) does not include components (A) to (H) described above. The (I) polymerization initiator can accelerate the reaction of the (H) radical polymerizable resin and accelerate the curing of the resin composition. The (I) polymerization initiator may be used alone or in combination of two or more types.

[0221] (I) As polymerization initiators, compounds that can generate free radicals when heated may be used. (I) Examples of polymerization initiators include peroxide-based radical polymerization initiators and azo-based radical polymerization initiators, with peroxide-based radical polymerization initiators being preferred.

[0222] Examples of peroxide-based radical polymerization initiators include hydroperoxide compounds such as 1,1,3,3-tetramethylbutyl hydroperoxide; dialkylperoxide compounds such as tert-butylcumyl peroxide, di-tert-butyl peroxide, di-tert-hexyl peroxide, dicumyl peroxide, 1,4-bis(1-tert-butylperoxy-1-methylethyl)benzene, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; and diacylperoxide compounds such as dilauroyl peroxide, didecanoyl peroxide, dicyclohexyl peroxydicarbonate, and bis(4-tert-butylcyclohexyl) peroxydicarbonate. Examples of peroxyester compounds include tert-butyl peroxyacetate, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl monocarbonate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyneodecanoate, tert-hexyl peroxyisopropyl monocarbonate, tert-butyl peroxylaurate, (1,1-dimethylpropyl)2-ethyl perhexanoate, tert-butyl 2-ethyl perhexanoate, tert-butyl 3,5,5-trimethyl perhexanoate, tert-butyl peroxy-2-ethylhexyl monocarbonate, tert-butyl peroxymaleic acid, and others.

[0223] Examples of azo radical polymerization initiators include azonitrile compounds such as 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitride), 1-[(1-cyano-1-methylethyl)azo]formamide, and 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile; 2,2'-azobis[2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide], and 2,2'-azobis[2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide]. Examples include azoamide compounds such as methyl)ethyl[propionamide], 2,2'-azobis[2-methyl-N-[2-(1-hydroxybutyl)]-propionamide], 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)-propionamide], 2,2'-azobis(2-methylpropionamide) dihydrate, 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), and 2,2'-azobis(N-cyclohexyl-2-methylpropionamide); and alkylazo compounds such as 2,2'-azobis(2,4,4-trimethylpentane) and 2,2'-azobis(2-methylpropane).

[0224] (I) Examples of commercially available polymerization initiators include NOF Corporation's "Perbutyl C", "Perbutyl A", "Perbutyl P", "Perbutyl L", "Perbutyl O", "Perbutyl ND", "Perbutyl Z", "Perbutyl I", "Permil P", "Permil D", "Perhexyl D", "Perhexyl A", "Perhexyl I", "Perhexyl Z", "Perhexyl ND", "Perhexyl O", and "Perhexyl PV".

[0225] (I) The amount of polymerization initiator is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, even more preferably 0.05% by mass or more, preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition.

[0226] (I) The amount of polymerization initiator is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, preferably 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less, based on 100% by mass of the resin component of the resin composition.

[0227] ((J) Any additives) The resin composition may further contain (J) any additives as optional components. (J) Any additives as components (J) do not include those corresponding to components (A) to (I) described above. (J) Optional additives include organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium 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; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; adhesion improvers such as urea silane; triazole-based adhesion ferrants, tetrazole-based adhesion ferrants, and triazine-based adhesion ferrants Examples of additives include: adhesion-improving agents; antioxidants such as hindered phenol 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 dispersants, polyoxyalkylene dispersants, acetylene dispersants, silicone 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. (J) Any additive may be used individually or in combination of two or more types.

[0228] ((K) solvent) The resin composition may further contain a solvent (K) as an optional volatile component in combination with the non-volatile components such as components (A) to (J) described above. Typically, an organic solvent is used as the solvent (K). Examples of organic solvents include: ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, and anisole; alcohol solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; and 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methoxypropionate. Examples include ether ester solvents such as tyl; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. (K) The solvent may be used alone or in combination of two or more types.

[0229] (K) The amount of solvent may be, for example, 60% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, based on 100% by mass of all components in the resin composition, and may also be 0% by mass.

[0230] (Method for manufacturing resin compositions) A resin composition can be manufactured, for example, by mixing components that may be included in the resin composition. The above-mentioned components may be mixed some or all at the same time, or sequentially. The temperature may be set appropriately during the mixing of each component, and thus heating and / or cooling may be performed temporarily or throughout the process. Furthermore, stirring or shaking may be performed during the mixing of each component.

[0231] (Properties of cured resin compositions) A cured product of the resin composition can be obtained by curing the resin composition described above. An insulating layer is formed by this cured product. Normally, heat is applied when curing a resin composition, so volatile components such as (K) solvent among the components contained in the resin composition may volatilize due to the heat during curing. Therefore, the cured product obtained by curing the resin composition may contain non-volatile components such as components (A) to (J) or their reaction products.

[0232] The cured product of the resin composition may have properties similar to those of the insulating layer of the circuit board. For example, if the resin composition is heated under the same conditions as the heat treatment in step (IV) to obtain a cured product, the cured product may have the same mean linear thermal expansion coefficient, glass transition temperature, and dielectric loss tangent as the insulating layer of the circuit board. [Examples]

[0233] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples. In the following explanation, "parts" and "%" refer to "parts by mass" and "% by mass," respectively, unless otherwise specified. Unless otherwise specified, the temperature and pressure conditions were room temperature (23°C) and atmospheric pressure (1 atm).

[0234] <Synthesis Example 1: Synthesis of Active Ester Resin (b)> In a flask equipped with a thermometer, dropping funnel, condenser, fractionation column, and stirrer, 320 g (2.0 mol) of 2,7-dihydroxynaphthalene, 184 g (1.7 mol) of benzyl alcohol, and 5.0 g of p-toluenesulfonic acid monohydrate were charged and stirred at room temperature while blowing in nitrogen. Then, the temperature was raised to 150°C and stirred for 4 hours while distilling off the water produced. After the reaction was complete, 900 g of methyl isobutyl ketone and 5.4 g of 20% sodium hydroxide aqueous solution were added to neutralize the mixture. Subsequently, the aqueous layer was removed by liquid-liquid extraction, and the mixture was washed three times with 280 g of water to remove methyl isobutyl ketone under reduced pressure, yielding 460 g of benzyl-modified naphthalene compound (b-1). The obtained benzyl-modified naphthalene compound (b-1) was a black solid with a hydroxyl group equivalent of 180 g / equivalent.

[0235] In a flask equipped with a thermometer, dropping funnel, condenser, fractionation column, and stirrer, 203.0 g of isophthalic acid chloride (2.0 moles of acid chloride groups) and 1400 g of toluene were charged, and the system was dissolved under reduced pressure and nitrogen purging. Next, 113.9 g (0.67 moles) of orthophenylphenol and 240 g of benzyl-modified naphthalene compound (b-1) (1.33 moles of phenolic hydroxyl groups) were charged, and the system was dissolved under reduced pressure and nitrogen purging. Subsequently, 0.70 g of tetrabutylammonium bromide was dissolved, and while purging with nitrogen gas, the system temperature was controlled to below 60°C, and 400 g of 20% sodium hydroxide aqueous solution was added dropwise over 3 hours. Stirring was then continued under these conditions for 1.0 hour.

[0236] After the reaction was complete, the mixture was allowed to stand and separated, and the aqueous layer was removed. Water was then added to the toluene layer containing the dissolved reactants, and the mixture was stirred for 15 minutes. The mixture was then allowed to stand and separated, and the aqueous layer was removed. This process was repeated until the pH of the aqueous layer reached 7. Subsequently, the water was removed by decanting to obtain an activated ester resin (b) in a toluene solution with a non-volatile content of 70% by mass. The activated ester group equivalent of the obtained activated ester resin (b) was 214 g / eq.

[0237] <Manufacturing Example A: Manufacturing of Resin Sheet A> Ten parts of bisphenol-type epoxy resin (Nippon Steel & Sumitomo Metal Chemicals Co., Ltd. "ZX1059", a 1:1 mixture of bisphenol A and bisphenol F, epoxy equivalent 165 g / eq.) and fifty parts of naphthol-type epoxy resin (Nippon Steel & Sumitomo Metal Chemicals Co., Ltd. "ESN475V", epoxy equivalent 332 g / eq.) were heated and dissolved in 40 parts of solvent naphtha with stirring. To this, 5 parts of phenoxy resin (Mitsubishi Chemical Corporation's "YX7553BH30," a 1:1 solution of MEK and cyclohexanone with a non-volatile content of 30% by mass), 5 parts of a phenolic curing agent having a triazine skeleton and novolac structure (DIC Corporation's "LA3018-50P," an active group equivalent of approximately 151 g / eq., a 2-methoxypropanol solution with a non-volatile content of 50%), 70 parts of an active ester resin (DIC Corporation's "HPC-8000-65T," an active group equivalent of approximately 223 g / eq., a toluene solution with a non-volatile content of 65% by mass), and (meth)acrylic acid ester (Shin-Nakamura Chemical Co., Ltd.'s "A-DOG"). , (meth)acryloyl group equivalent 156 g / eq.) 20 parts, carbodiimide-based curing agent (Nisshinbo Chemical Co., Ltd. "V-03", carbodiimide group equivalent 216 g / eq., toluene solution with 50% non-volatile content) 15 parts, curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), MEK solution with 10% non-volatile content) 6 parts, polymerization initiator (Perkmill D (NOF Co., Ltd., MEK solution with 20% non-volatile content)) 2 parts, spherical silica surface-treated with amine-based alkoxysilane compound (Shin-Etsu Chemical Co., Ltd. "KBM573") (average particle size 0.5 μm, specific surface area 5.8 m²) 2 370 parts of Admatex's "SO-C2" ( / g), 10 parts of cyclohexanone, and 10 parts of methyl ethyl ketone (MEK) were mixed and uniformly dispersed in a high-speed rotary mixer to prepare resin varnish A.

[0238] A polyethylene terephthalate (PET) film (Lintec Corporation's "AL5", 38 μm thick) with a release layer was prepared as a support. The resin varnish A was uniformly applied to the release layer of this support so that the thickness of the resin composition layer after drying was 40 μm. Then, the resin varnish A was dried at 80°C to 100°C (average 90°C) for 3 minutes to obtain a resin sheet A comprising the support and the resin composition layer.

[0239] <Manufacturing Example B: Manufacturing of Resin Sheet B> Fifteen parts of liquid bisphenol A type epoxy resin (Japan Epoxy Resin Co., Ltd. "jER828EL", epoxy equivalent 189 g / eq.) and fifteen parts of biphenyl type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000L", epoxy equivalent 271 g / eq.) were heated and dissolved in fifteen parts of methyl ethyl ketone and fifteen parts of cyclohexanone while stirring. To this, forty-three parts of naphthalene type active ester resin (DIC Corporation "EXB9411-65BK", active ester group equivalent 272 g / eq., toluene solution with 65% solids) were added, along with 0.15 parts of curing accelerator (Koei Chemical Industry Co., Ltd. 4-dimethylaminopyridine (DMAP)) and spherical silica surface-treated with phenylaminosilane (average particle size 0.5 μm, specific surface area 5.8 m²). 2 Resin varnish B was prepared by mixing 100 parts of Admatex's "SO-C2" (carbon content 0.18% per unit mass) with 15 parts of phenoxy resin (Mitsubishi Chemical's "YL6954BH30", MEK solution with 30% solids by mass, weight-average molecular weight 40000) and uniformly dispersing them in a high-speed rotary mixer.

[0240] A polyethylene terephthalate (PET) film (Lintec Corporation's "AL5", 38 μm thick) with a release layer was prepared as a support. The resin varnish B was uniformly applied to the release layer of this support so that the thickness of the resin composition layer after drying was 40 μm. Then, the resin varnish B was dried at 80°C to 100°C (average 90°C) for 3 minutes to obtain a resin sheet B comprising the support and the resin composition layer.

[0241] <Manufacturing Example C: Manufacturing of Resin Sheet C> Sixteen parts of naphthalene-type epoxy resin (DIC Corporation "HP-4032-SS", epoxy equivalent 144 g / eq.) and six parts of biphenyl-type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000L", epoxy equivalent 271 g / eq.) were heated and dissolved in six parts of methyl ethyl ketone and fifteen parts of cyclohexanone while stirring. To this, ten parts of naphthalene-type active ester resin (DIC Corporation "HPC-8150-62T", active ester group equivalent 230 g / eq., toluene solution with 62% solids) were added, six parts of active ester resin (b) (synthesized in Synthesis Example 1, toluene solution with 70% solids by mass) were added, and two parts of carbodiimide-type curing agent (Nisshinbo Chemical Co., Ltd. "V-03", carbodiimide group equivalent 216 g / eq., toluene solution with 50% non-volatile content) were added. 1 part of a phenolic curing agent having a triazine skeleton and novolac structure (DIC Corporation's "LA3018-50P", active group equivalent approximately 151 g / eq., 2-methoxypropanol solution with 50% non-volatile content) 4 parts, curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), MEK solution with 10% by mass non-volatile content) 10 parts, spherical silica surface-treated with phenylaminosilane (average particle size 0.5 μm, specific surface area 5.8 m²) 2 A resin varnish C was prepared by mixing 120 parts of Admatex's "SO-C2" (carbon content 0.18% per unit mass), 4 parts of phenoxy resin (Mitsubishi Chemical's "YX7553BH30," a 1:1 solution of MEK and cyclohexanone with 30% non-volatile content), and 1 part of organic filler (Dow's "EXL-2655," core-shell type particles containing rubber components in the core), and uniformly dispersing them in a high-speed rotary mixer.

[0242] A polyethylene terephthalate (PET) film (Lintec Corporation's "AL5", 38 μm thick) with a release layer was prepared as a support. The aforementioned resin varnish C was uniformly applied to the release layer of this support so that the thickness of the resin composition layer after drying was 40 μm. Then, the resin varnish C was dried at 80°C to 100°C (average 90°C) for 3 minutes to obtain a resin sheet C containing the support and the resin composition layer.

[0243] <Summary of the composition of the resin composition> The compositions of the resin compositions used in the above manufacturing examples A to C are summarized in Table 1 below. In Table 1 below, the meanings of the abbreviations are as follows. "NVC": Non-volatile component content. "Activated ester equivalent ratio": (A) The equivalent ratio of the active ester groups of the epoxy resin to the epoxy groups of the epoxy resin (B).

[0244] [Table 1]

[0245] <Example 1> (1) Surface preparation of the inner layer substrate: A glass cloth substrate epoxy resin double-sided copper-clad laminate (copper layer thickness 18 μm, substrate thickness 0.8 mm, Panasonic Electric Works "R1515A") with copper layers on both surfaces was prepared as the inner layer substrate. The surface of the copper layer was roughened by immersing both sides of the inner layer substrate in an etching agent (MEC "CZ8100").

[0246] (2) Lamination of resin sheets: Resin sheet A was cut to a size of 490 mm x 320 mm. The cut resin sheet A was laminated to both sides of the inner layer substrate using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., 2-stage build-up laminator "CVP700"). This lamination was performed so that the resin composition layer of resin sheet A was bonded to the inner layer substrate. Furthermore, this lamination was performed after adjusting the atmospheric pressure to 13 hPa or less by depressurizing for 30 seconds, at 120°C and a pressure of 10 kgf / cm². 2 This was carried out by applying pressure for 30 seconds. Subsequently, the temperature was set to 120°C and the pressure to 14 kgf / cm². 2 A heat press was applied for 60 seconds.

[0247] (3) Thermosetting of the resin composition layer: An inner layer substrate laminated with resin sheet A was subjected to a heat-curing treatment that included heating in a 130°C oven for 30 minutes, and then transferring it to a 170°C oven and heating for another 30 minutes, thereby heat-curing the resin composition layer and forming an intermediate cured layer. Subsequently, the support was removed to obtain a "cured substrate" having the intermediate cured layer, inner layer substrate, and intermediate cured layer in that order.

[0248] (4) Roughening treatment: The cured substrate was immersed in a swelling solution (Atotec Japan's "Swelling Dip Securigant P," an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60°C for 5 minutes. Next, the cured substrate was immersed in an oxidizing agent solution (Atotec Japan's "Concentrate Compact CP," an aqueous solution of approximately 6% potassium permanganate and approximately 4% sodium hydroxide) at 80°C for 20 minutes. Then, the cured substrate was immersed in a neutralizing solution (Atotec Japan's "Reduction Solution Securigant P," an aqueous sulfuric acid solution) at 40°C for 5 minutes. After that, the cured substrate was dried at 80°C for 15 minutes to obtain a "roughened substrate."

[0249] (5) Formation of the seed layer (electroless copper plating layer): In order to form a conductive layer on the surface of the roughened substrate manufactured in process (4), a plating process (copper plating process using chemicals manufactured by Attec Japan Co., Ltd.) including the following steps a to e was performed to form the conductive layer.

[0250] a. Alkaline cleaning (cleaning and charge adjustment of the intermediate hardened layer surface): The surface of the roughened substrate was cleaned at 60°C for 5 minutes using Cleaning Cleaner Securiganth 902 (product name).

[0251] b. Pre-dip (adjustment of the surface charge of the intermediate hardened layer for Pd impartment): The surface of the roughened substrate was treated with Pre.DipNeoganth B (trade name) at room temperature for 1 minute.

[0252] c. Activator application (application of Pd to the surface of the intermediate cured layer): The surface of the roughened substrate was treated with Activator Neoganth 834 (trade name) at 35 °C for 5 minutes.

[0253] d. Reduction (reduction of Pd applied to the intermediate cured layer): The surface of the roughened substrate was treated with a mixture of Reducer Neoganth WA (trade name) and Reducer Acceralator 810 mod. (trade name) at 30 °C for 5 minutes.

[0254] e. Electroless copper plating process (precipitation of Cu on the surface (Pd surface) of the intermediate cured layer): Using a mixture of Basic Solution Printganth MSK-DK (trade name), Copper solution Printganth MSK (trade name), Stabilizer Printganth MSK-DK (trade name), and Reducer Cu (trade name), the surface of the roughened substrate was treated at 35 °C for 15 minutes to form an electroless copper plating layer (the first conductor layer). The thickness of the formed electroless copper plating layer was 250 nm to 350 nm. By this electroless copper plating process, an intermediate laminate 1 having a layer structure of electroless copper plating layer / intermediate cured layer / inner layer substrate / intermediate cured layer / electroless copper plating layer was obtained (Process (I)).

[0255] (6) Dry film lamination: A dry film (RY-5115 manufactured by Resonac) was laminated on one side of the intermediate laminate 1 using a batch type vacuum pressure laminator (MVLP-500 manufactured by Meiki Seisakusho). The lamination was carried out by reducing the pressure for 30 seconds to make the atmospheric pressure 13 hPa or less, and then pressure bonding at 100 °C and a pressure of 0.74 MPa for 30 seconds.

[0256] (7) Exposure: Using an exposure machine (Ushio Inc.'s projection exposure machine "UX-2240SM"), a glass mask with 10 comb-tooth patterns was used to expose a dry film to form wiring for the comb-tooth pattern (line / space (L / S) = 9 μm / 7 μm, wiring length = 15 mm, 16 lines) (125 mJ). Subsequently, development was performed using a 1 mass% sodium carbonate aqueous solution. Development removed the dry film in the areas corresponding to the comb-tooth pattern, exposing the electroless copper plating layer.

[0257] (8) Formation of the electroplating layer: Copper sulfate electroplating was performed, and an electroplated layer (second conductive layer) with a thickness of 8 μm was formed on the electroless copper plating layer in the portion exposed in step (7) (step (II)).

[0258] (9) Heat treatment: The intermediate laminate 1, which had an electroplated layer formed in step (8), was subjected to a heat treatment under the conditions of a heating temperature of 200°C and a heating time of 90 minutes (step (IV)). This heat treatment further cured the intermediate hardened layer, and an insulating layer was obtained.

[0259] (10) Formation of comb-tooth pattern wiring: After step (9), the surface of the intermediate laminate 1 was cleaned to remove the dry film. Then, using a flash etching etchant (SAC process etchant manufactured by Ebara Electric Industries, Ltd.), the electroless copper plating layer in unwanted areas (i.e., the electroless plating layer in areas where the electroplating layer was not formed) was removed (step (III)). Through this operation, a circuit board having a layer structure of conductor layer (electroless copper plating layer and electroplating layer) / insulating layer / inner layer substrate / insulating layer was obtained. The conductor layer formed a wiring layer having the comb-tooth pattern described above when viewed from the thickness direction.

[0260] (11) CZ treatment of the conductive layer: A micro-etching agent (MEC's ​​"CZ8201") was brought into contact with the conductive layer of the circuit board obtained in step (10) during a CZ treatment. This circuit board after the CZ treatment is referred to as "Evaluation Board 1".

[0261] <Example 2> Evaluation substrate 2 was manufactured in the same manner as in Example 1, except that resin sheet B manufactured in manufacturing example B was used instead of resin sheet A.

[0262] <Example 3> The evaluation substrate 3 was manufactured in the same manner as in Example 1, except that resin sheet C manufactured in manufacturing example C was used instead of resin sheet A.

[0263] <Example 4> The evaluation substrate 4 was manufactured in the same manner as in Example 1, except that resin sheet C manufactured in manufacturing example C was used instead of resin sheet A, and the heat treatment conditions in step (9) were changed to 210°C for 60 minutes.

[0264] <Example 5> The evaluation substrate 5 was manufactured in the same manner as in Example 1, except that resin sheet C manufactured in manufacturing example C was used instead of resin sheet A, and the heat treatment conditions in step (9) were changed to 170°C for 90 minutes.

[0265] <Comparative Example 1> The heat treatment in step (9) was omitted. Instead of step (9), after removing the unnecessary electroless copper plating layer in step (10), the circuit board was heat-treated at 200°C for 90 minutes. Except for the above, evaluation board 6 was manufactured in the same manner as in Example 1.

[0266] <Comparative Example 2> Instead of resin sheet A, resin sheet B manufactured in manufacturing example B was used. Also, the heat treatment in step (9) was omitted. Instead of step (9), after removing the unnecessary electroless copper plating layer in step (10), the circuit board was heat-treated at 200°C for 90 minutes. Except for the above, evaluation board 7 was manufactured in the same manner as in Example 1.

[0267] <Comparative Example 3> Instead of the resin sheet A, the resin sheet C manufactured in Production Example C was used. Also, the heat treatment in step (9) was not performed. Instead of this step (9), after removing the electroless copper surface layer of the unnecessary portion in step (10), the circuit board was heat-treated at 200 °C for 90 minutes. Except for the above matters, an evaluation substrate 8 was manufactured in the same manner as in Example 1.

[0268] <Comparative Example 4> An evaluation substrate 9 was manufactured in the same manner as in Example 1, except that the resin sheet C manufactured in Production Example C was used instead of the resin sheet A and the heat treatment in step (9) was not carried out.

[0269] <Wiring Lifting Evaluation Test> The wiring layers (10 comb tooth patterns × 16 lines each) of the comb tooth patterns of each of the evaluation substrates 1 to 9 were observed. The number X of wirings peeled off from the insulating layer was counted. The wiring lifting occurrence rate Y was calculated by the following formula (M1). Wiring lifting occurrence rate Y (%) = X / 160 × 100 (M1) Based on the obtained wiring lifting occurrence rate Y, evaluation was carried out according to the following evaluation criteria.​​​​​​​​​​​​​​​The resin sheets produced in the manufacturing example were heat-cured under the heat treatment conditions described in each example and comparative example, and the support was removed to obtain a cured resin composition layer. In Comparative Example 4, no heat treatment was performed, so in the evaluation test for Comparative Example 4, the resin composition was heat-cured under the conditions described in "(3) Heat curing of the resin composition layer". From the obtained cured product, evaluation samples measuring 20 mm in length and 6 mm in width were cut out. For each evaluation sample, the average linear thermal expansion coefficient (CTE1) from 25°C to 150°C was measured using a thermomechanical analyzer (TMA) (manufactured by Rigaku Corporation) at a heating rate of 5°C / min from 25°C to 250°C. The same evaluation sample was measured twice, and the second value was recorded. The linear thermal expansion coefficient CTE1 of the evaluation samples obtained in this way corresponds to the average linear thermal expansion coefficient after heat treatment of the insulating layer obtained in each example and comparative example. This average linear thermal expansion coefficient CTE1 was evaluated according to the following evaluation criteria. "Good": CTE1(ppm / K)≦25 "Bad": CTE1(ppm / K)>25

[0272] <Evaluation test of glass transition temperature (Tg) of cured resin composition> Based on the results obtained from the evaluation test of the mean linear thermal expansion coefficient (CTE) described above, the glass transition temperature (Tg) of the evaluation sample was measured. The glass transition temperature (Tg) of the evaluation sample thus obtained corresponds to the glass transition temperature of the insulating layer obtained in each example and comparative example. This glass transition temperature (Tg) was evaluated according to the following evaluation criteria. "Good": Tg(℃)≧140 "Poor": Tg(℃)<140

[0273] <Measurement of dielectric loss tangent> The resin sheets produced in the manufacturing example were heat-cured under the heat treatment conditions described in each example and comparative example, and the support was removed to obtain a cured resin composition layer. In Comparative Example 4, no heat treatment was performed, so in the measurement for Comparative Example 4, the resin composition was heat-cured under the conditions described in "(3) Heat curing of the resin composition layer". Test pieces measuring 80 mm in length and 2 mm in width were cut from the obtained cured material. For each test piece, the dielectric loss tangent (Df) was measured using a measuring device (Agilent Technologies "HP8362B") by the cavity resonance perturbation method at a measurement frequency of 5.8 GHz and a measurement temperature of 23 °C. Measurements were performed on two test pieces, and the average was calculated. The dielectric loss tangent (Df) of the test pieces obtained in this way corresponds to the dielectric loss tangent of the insulating layer after heat treatment obtained in each example and comparative example. This dielectric loss tangent (Df) was evaluated according to the following evaluation criteria. "Good": Df(-)≦0.005 "Bad": Df(-)>0.005

[0274] <Result> The results of the above-mentioned examples and comparative examples are shown in the table below. In the table below, the meanings of the abbreviations are as follows. In the "Timing" column, "Before": Heat treatment was performed before removing the unnecessary electroless copper plating layer in process (10). In the "Timing" column, "Later": Heat treatment was performed after removing the unnecessary electroless copper plating layer in process (10). "Occurrence Rate Y": Wiring loosening occurrence rate "Ra": Arithmetic mean roughness Ra "CTE1": mean linear thermal expansion coefficient "Tg": Glass transition temperature "Df": Dielectric Loss Tangent

[0275] [Table 2]

[0276] <Consideration> As shown in Table 2, by performing the heat treatment of the intermediate hardened layer before step (III) (i.e., the step of removing the unnecessary portion of the first conductor layer), the wiring lifting phenomenon in the CZ treatment of the conductor layer using a micro-etchant can be suppressed. [Explanation of symbols]

[0277] 100 Intermediate Laminate 110 Inner layer substrate 120 Intermediate hardening layer 120U Intermediate hardened layer surface 121 Resin composition layer 130 First Conductor Layer 131 Part of the first conductor layer 132 Part of the first conductor layer 140 Second Conductor Layer 150 Insulating layer 150U insulating layer surface 160 Conductor Layers 200 Resin Sheets (Metal-attached Resin Sheets) 210 Metal foil 211 Carrier metal foil layer 310 masks 400 circuit boards 900 Intermediate products 910 Insulating layer Surface of the 910U insulating layer 911U Surface portion of the insulating layer (the portion where the conductive layer is formed) 912U - Surface portion of the insulating layer (the portion where the conductive layer is not formed) 920 Conductor layer 921 Corner 930 Boundary part

Claims

1. Step (I) of preparing an intermediate laminate comprising an inner layer substrate, an intermediate hardened layer formed on the inner layer substrate, and a first conductive layer bonded to the intermediate hardened layer. After step (I), step (II) is to form a second conductor layer on a portion of the first conductor layer. After step (II), step (III) is performed to remove the first conductor layer in the portion where the second conductor layer was not formed, and, Between steps (I) and (III), the process includes step (IV), in which the intermediate hardened layer is subjected to heat treatment to obtain an insulating layer; A method for manufacturing a circuit board, wherein the intermediate cured layer is a layer obtained by curing a resin composition layer containing (A) an epoxy resin and (B) an active ester resin.

2. Process (I) is Steps to form a resin composition layer on an inner layer substrate (I-a1), A step (I-a2) in which a resin composition layer is subjected to a curing treatment to form an intermediate cured layer, and Steps to form a first conductive layer on an intermediate hardened layer (I-a3), A method for manufacturing a circuit board according to claim 1, comprising the following in this order.

3. The method for manufacturing a circuit board according to claim 2, wherein step (I) includes a step (I-a4) of roughening the intermediate hardened layer between steps (I-a2) and (I-a3).

4. Process (I) is A process (I-b1) of laminating a resin sheet comprising a metal foil having a first conductive layer and a resin composition layer bonded to the first conductive layer of the metal foil, and an inner layer substrate, such that the resin composition layer and the inner layer substrate are bonded together, and Step (I-b2) to form an intermediate cured layer by curing the resin composition layer. A method for manufacturing a circuit board according to claim 1, comprising the following in this order.

5. A method for manufacturing a circuit board according to claim 1, further comprising step (V) of contacting the second conductive layer with an etching agent after step (III).

6. A method for manufacturing a circuit board according to claim 1, wherein the equivalent ratio of (A) the epoxy groups of the epoxy resin to (B) the active ester groups of the active ester resin is 0.1 or more.

7. The method for manufacturing a circuit board according to claim 1, wherein the arithmetic mean roughness Ra of the surface of the intermediate hardened layer of the intermediate laminate facing the first conductor layer is 250 nm or less.

8. A method for manufacturing a circuit board according to claim 1, wherein the mean linear thermal expansion coefficient CTE of the insulating layer is 25 ppm / K or less.

9. A method for manufacturing a circuit board according to claim 1, wherein the glass transition temperature Tg of the insulating layer is 140°C or higher.

10. A method for manufacturing a circuit board according to claim 1, wherein the thickness of the first conductor layer is 100 nm or more and 1000 nm or less.

11. The method for manufacturing a circuit board according to claim 1, wherein the length of the second conductor layer after step (III) is 10 mm or more.

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