Resin sheet, manufacturing method thereof, and defect detection method

Abstract

To provide a resin sheet which can enhance detection accuracy of defects in a resin composition layer.SOLUTION: A resin sheet includes a support having a release layer, and a resin composition layer formed on the release layer of the support, wherein the resin composition layer contains a resin composition, a dielectric loss tangent of the cured product of the resin composition is 0.05 or less, and the number of defects with a maximum diameter of 10 μm or more possessed by the support is 5 pieces / cm2 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin sheet, a manufacturing method thereof, and a defect detection method. [Background technology]

[0002] Printed wiring boards are widely used in various electronic devices. A known method for manufacturing printed wiring boards is a build-up method in which insulating layers and conductor layers are alternately stacked on an inner layer substrate. The insulating layer is formed, for example, by using a resin sheet having a resin composition layer formed on a support, laminating the resin sheet on the inner layer substrate to form a resin composition layer, and thermally curing the resin composition layer (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-23714 Summary of the Invention [Problem to be solved by the invention]

[0004] The resin composition layer may contain defects such as foreign matter and air bubbles. If the resin composition layer contains defects, the defects may remain in the insulating layer.

[0005] In recent years, the need for miniaturization of electronic devices and electronic components has led to a demand for finer and denser wiring in printed wiring boards. As the trend toward finer and denser wiring advances, defects smaller than conventional defects can hinder wiring formation. Therefore, there is a need to remove even smaller defects from resin composition layers. Specifically, there is a demand for a technology to detect defects on the order of several tens of micrometers contained in resin composition layers.

[0006] Defects of several hundred microns or more can be detected by visual observation. However, small defects of several tens of microns are difficult to detect by visual observation. Therefore, one possible method for detecting such small defects is to perform optical observation of the resin composition using an inspection device such as a microscope or an automatic visual inspection device. However, when the present inventors attempted to detect small defects of several tens of microns using the inspection device, the frequency of false detection was high, and therefore the detection accuracy of small defects in the resin composition layer was low. Specifically, in areas where there were no small defects in the resin composition layer, the detection result frequently indicated that the area contained defects.

[0007] The present invention was devised in consideration of the above-mentioned problems, and aims to provide a resin sheet and a manufacturing method thereof that can improve the accuracy of detecting defects in a resin composition layer, and a defect detection method that can detect defects in a resin composition layer of a resin sheet with high accuracy. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, the present inventors have discovered a resin sheet comprising a support and a resin composition layer formed on the support, wherein the number of defects in the support having a maximum diameter of 10 μm or more is 5 / cm. 2 The present invention was completed based on the discovery that the following can solve the above problems. That is, the present invention includes the following.

[0009] [1] A support and a resin composition layer formed on the support, The number of defects having a maximum diameter of 10 μm or more on the support is 5 / cm 2 Below is a resin sheet. [2] The resin sheet according to [1], wherein the defect is a point that can be detected by optical observation. [3] The resin sheet according to [1] or [2], wherein the defect is located inside the support. [4] The resin sheet according to any one of [1] to [3], wherein the support is a plastic film. [5] The resin sheet according to any one of [1] to [4], which is for forming an insulating layer. [6] A method for producing a resin sheet according to any one of [1] to [5], forming a resin composition layer on a support; and simultaneously optically observing the support and the resin composition layer to detect defects; The number of defects having a maximum diameter of 10 μm or more on the support is 5 / cm 2 The following is a method for manufacturing a resin sheet. [7] A method for detecting defects in a resin composition layer of a resin sheet having a support and a resin composition layer formed on the support, comprising: a step of simultaneously optically observing the support and the resin composition layer to detect defects, The number of defects having a maximum diameter of 10 μm or more on the support is 5 / cm 2 The defect detection method is as follows. [8] The defect detection method according to [7], wherein the defect in the support, the maximum diameter of which is 10 μm or more, is located inside the support. [9] The defect detection method according to [7] or [8], wherein the support is a plastic film. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a resin sheet and a manufacturing method thereof that can improve the accuracy of detecting defects in a resin composition layer; and a defect detection method that can detect defects in a resin composition layer of a resin sheet with high accuracy. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a front view schematically showing an example of a resin sheet manufacturing apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0012] 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 can be implemented with any modifications within the scope of the claims and their equivalents.

[0013] In the following description, the term "(meth)acrylic" includes acrylic, methacrylic, and combinations thereof. The term "(meth)acrylate" includes acrylate, methacrylate, and combinations thereof. The term "(meth)acryloyl" includes acryloyl, methacryloyl, and combinations thereof.

[0014] [Resin sheet overview] A resin sheet according to one embodiment of the present invention comprises a support and a resin composition layer formed on the support. The resin composition layer contains a resin composition, preferably only a resin composition. The support of the resin sheet according to this embodiment has a number of defects with a maximum diameter of 10 μm or more within a specific range. Here, unless otherwise specified, "defects" refer to points that can be detected by optical observation.

[0015] The components of a resin sheet, such as a support and a resin composition layer, are generally manufactured to be uniform in the in-plane direction perpendicular to the thickness direction. Therefore, the components, such as the support and the resin composition, have a uniform composition in the in-plane direction when viewed macroscopically. Therefore, when the support, the resin composition layer, and the resin sheet containing them are optically observed, ideally, a uniform image is obtained.

[0016] However, in actual manufacturing, defects that form an image different from the normal portion may be formed by optical observation. The "normal portion" refers to the portion that forms the uniform image described above, and usually refers to a portion that has a uniform composition. Generally, this normal portion occupies the majority of the measurement area that is optically observed. On the other hand, a "defect" refers to a portion other than the normal portion. This defect usually appears as an abnormal point surrounded by normal portions, and therefore forms an image different from the surrounding normal portions in the image obtained by optical observation.

[0017] Specifically, in images obtained by optical observation, defects typically form images with contrast and / or color tone different from that of normal portions. Examples of defect colors include white, brown, black, and translucent, but defects that do not fall into these categories may also be included. Defects may have a refractive index different from that of normal portions, resulting in light refraction or reflection, resulting in an image that is transparent but has a different contrast and / or color tone with a different outline. Furthermore, examples of defect shapes include oval, irregular, or a combination of these shapes, but defects that do not fall into these categories may also be included. Unless otherwise specified, the term "defect shape" refers to the shape of a defect that appears in an image obtained by optical observation, for example, the shape of a defect obtained by observation from the thickness direction.

[0018] Defects in a resin sheet can include defects in the support and defects in the resin composition layer. Defects in the support include, for example, fragments of the support material (e.g., fragments of resin pellets), lumps resulting from unintended localized reactions such as polymerization and crosslinking, foreign matter introduced during the support's manufacturing process, and air bubbles, scratches, and unevenness formed during the support's manufacturing process. These defects are generally difficult to remove by cleaning. On the other hand, defects in the resin composition layer typically refer to air bubbles, foreign matter, pinholes, coating streaks, and coating voids contained in the resin composition layer. Defects in the resin composition layer can generally cause process defects such as defective formation of an insulating layer or wiring layer, as well as product defects such as cracks in the insulating layer. Therefore, it is desirable to identify and remove portions of the resin composition layer containing defects such as air bubbles and foreign matter in the resin sheet.

[0019] When a defect detection method including optical observation of the resin sheet is performed on the resin sheet according to this embodiment, defects such as foreign matter and air bubbles in the resin sheet can be detected. Most, preferably all, of the defects in the resin sheet thus detected correspond to defects in the resin composition layer. Therefore, the resin sheet according to this embodiment can reduce the frequency of false detection of defects in the resin composition layer by the defect detection method, thereby improving the detection accuracy of defects in the resin composition layer.

[0020] [Support] The support is a member that supports the resin composition layer. This support may have defects with a maximum diameter of 10 μm or more, but the number of defects is small. Preferably, the support does not have defects with a maximum diameter of 10 μm or more. Specifically, the number of defects with a maximum diameter of 10 μm or more that the support has is usually 5 / cm. 2 Less than 4 pieces / cm 2 Less than 3 pieces / cm is more preferable. 2 Less than 2 / cm, more preferably 2 Less than 1 / cm is particularly preferable. 2 Ideally, it should be 0 particles / cm 2 is.

[0021] The maximum diameter of defects refers to the maximum diameter of the image formed by the defects in the image obtained by optical observation. Therefore, the maximum diameter of defects in the support can be measured by optically observing the support. This optical observation of the support can be performed by the same method as the optical observation performed in the resin sheet manufacturing method described below. Usually, the maximum diameter and number of defects in the support can be measured by optically observing the support alone. Specific measurement methods can be, for example, the methods described in Reference Examples 1 to 5.

[0022] The support is preferably made of a material that can transmit light of the wavelength used in optical observation. In this case, it is preferable that the light can transmit through the support to an extent that defects in the support can be detected. Since optical observation is usually performed using visible light, the support is preferably made of a transparent or translucent material that can transmit visible light.

[0023] In one example, the light transmittance of the support at a measurement wavelength of 550 nm is preferably 60% or more, more preferably 70% or more, particularly preferably 80% or more, and is usually 100% or less. The light transmittance can be measured using an ultraviolet / near-infrared spectrophotometer (for example, Shimadzu Corporation's "UV3100PC"). The measurement conditions can be as follows: measurement wavelength range: 300 nm to 2600 nm, sampling pitch: 1 nm, exposure time: 103 seconds (time from start to finish of measurement), integrating sphere: yes, slit width: 20 nm.

[0024] In one example, the haze value of the support is preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less. The haze value refers to the ratio (percentage) of diffused light to the total light passing through a material. The haze value can be measured using a haze meter (for example, the "HZ-V3" haze meter manufactured by Suga Test Instruments).

[0025] Examples of materials for the support include plastic materials. Examples of plastic materials include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide. Among these, polyethylene terephthalate, polyethylene naphthalate, and polyimide are preferred, and polyimide is particularly preferred.

[0026] The shape of the support may be plate-like, but is preferably film-like. Therefore, as the support, a plastic film containing the above-mentioned plastic material is preferred, and a polyimide film is particularly preferred. Furthermore, the support may be a sheet-like film, but from the viewpoint of enabling continuous production of the resin sheet and improving production efficiency, a long film is preferred. Unless otherwise specified, a long film refers to a film having a length that can be wound into a roll, and can be, for example, a film having a length 10 times or more relative to its width.

[0027] The surface of the support that is to be bonded to the resin composition layer may be subjected to a matte treatment, a corona treatment, or an antistatic treatment.

[0028] The support may have a release layer on the surface to be bonded to the resin composition layer. Therefore, the support may have, for example, a support layer made of the above-mentioned plastic material and a release layer formed on the support layer. The release layer is usually formed using a release agent. Examples of the release agent include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins.

[0029] The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, more preferably 10 μm to 60 μm. When a support having a release layer is used, it is preferable that the thickness of the entire support including the release layer is in the above range.

[0030] The support can be selected from commercially available products. However, when the support is a plastic film containing a plastic material, it is generally difficult to use a commercially available plastic film as a support as is. Generally, plastic films have defects with a maximum diameter of 10 μm or more at a rate of 5 / cm. 2These defects are more frequent. For example, plastic films produced by melt casting using a solution of plastic material may contain some of the plastic pellets used as raw materials that do not dissolve in the solution, resulting in fragments remaining in the plastic film and forming defects. Also, plastic films produced by melt extrusion using a thermally molten plastic material may contain some of the plastic pellets that do not melt, resulting in fragments remaining in the plastic film and forming defects. Furthermore, plastic film manufacturing methods may involve stretching and cooling the film while heating it for purposes such as thickness control. During this stretching process, some of the material may undergo reactions such as polymerization, crosslinking, or modification. Such reactions can result in the formation of clumps in the film with a different composition from the surrounding material, which can then form defects. Furthermore, plastic films generally contain additives such as antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, viscosity reducers, thermal stabilizers, and lubricants to improve moldability and the properties of molded products. However, these additives may remain unmelted or aggregate during the manufacturing process, resulting in defects. It is technically and cost-effectively difficult to completely eliminate these defects, so commercially available plastic films usually have a maximum of 5 defects per cm with a maximum diameter of 10 μm or more. 2 In addition, even if a plastic film has no defects if it is small in area, a long film has defects with a maximum diameter of 10 μm or more at a frequency of 5 / cm2. 2 The following is generally difficult to achieve even with today's advanced film manufacturing technology.

[0031] Therefore, when using a commercially available plastic film as a support, it is preferable to select a film with few of the above defects. In addition, since the film may contain defects as described above, the film is optically observed, and the number of defects with a maximum diameter of 10 μm or more is determined to be 5 / cm. 2 It is preferable to remove the part with a higher frequency and use the remaining part as a support. 2When a high-grade film from which the more frequently contained portions have been removed is commercially available, such a high-grade film may be used as the support.

[0032] [Resin composition layer] The resin composition layer contains a resin composition. This resin composition can be cured by one or both of heat and light and used as a component of a circuit board such as a printed wiring board or a semiconductor chip package. Examples of components of a circuit board to which the cured product obtained by curing the resin composition can be applied include insulating layers, solder resists, underfill materials, die bonding materials, semiconductor encapsulants, hole-filling resins, and component-embedding resins. Therefore, a composition containing (A) a curable resin can be used as the resin composition. Specific examples of the composition of the resin composition will be described below, but resin compositions other than those exemplified below may also be used.

[0033] The (A) curable resin that may be contained in the resin composition is usually selected from the group consisting of thermosetting resins and photocurable resins. As the (A) curable resin, only a thermosetting resin may be used, only a photocurable resin may be used, or a combination of a thermosetting resin and a photocurable resin may be used. Furthermore, the (A) curable resin may be used alone or in combination of two or more types.

[0034] As the thermosetting resin, a resin that can be cured when heat is applied can be used. Examples of thermosetting resins include epoxy resins, phenolic resins, active ester resins, cyanate resins, carbodiimide resins, acid anhydride resins, amine resins, benzoxazine resins, thiol resins, and radical polymerizable resins. One type of thermosetting resin may be used alone, or two or more types may be used in combination. Among these, it is preferable that the thermosetting resin contains at least one type selected from the group consisting of epoxy resins, phenolic resins, active ester resins, cyanate resins, and radical polymerizable resins.

[0035] In one example, it is preferable to use a combination of an epoxy resin and a resin capable of reacting with the epoxy resin to cure the resin composition. Hereinafter, a resin capable of reacting with an epoxy resin to cure the resin composition may be referred to as a "curing agent." Examples of curing agents include phenolic resins, active ester resins, cyanate resins, carbodiimide resins, acid anhydride resins, amine resins, benzoxazine resins, and thiol resins. Among these, phenolic resins, active ester resins, cyanate resins, and carbodiimide resins are preferred, and phenolic resins and active ester resins are more preferred. Furthermore, one type of curing agent may be used alone, or two or more types may be used in combination.

[0036] Epoxy resin is a curable resin having an epoxy group. Examples of epoxy resins include bixylenol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol AF-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol novolac-type epoxy resins, phenol novolac-type epoxy resins, tert-butyl-catechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ester-type epoxy resins, cresol novolac-type epoxy resins, phenol aralkyl-type epoxy resins, biphenyl-type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane-type epoxy resins, cyclohexane dimethanol-type epoxy resins, naphthylene ether-type epoxy resins, trimethylol-type epoxy resins, tetraphenylethane-type epoxy resins, isocyanurate-type epoxy resins, and phenolphthalimidine-type epoxy resins. The epoxy resin may be used alone or in combination of two or more.

[0037] From the viewpoint of obtaining a cured product having excellent heat resistance, the epoxy resin preferably contains an epoxy resin containing an aromatic structure. The aromatic structure is a chemical structure generally defined as aromatic, and also includes polycyclic aromatic rings and aromatic heterocycles. Examples of epoxy resins containing an aromatic structure include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AF type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol novolac type epoxy resins, phenol novolac type epoxy resins, tert-butyl-catechol type epoxy resins, naphthalene type epoxy resins, naphthol type epoxy resins, anthracene type epoxy resins, bisxyleneol type epoxy resins, glycidylamine type epoxy resins having an aromatic structure, glycidyl ester type epoxy resins having an aromatic structure, cresol novolac type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins having an aromatic structure, epoxy resins having a butadiene structure having an aromatic structure, alicyclic epoxy resins having an aromatic structure, heterocyclic epoxy resins, spiro ring-containing epoxy resins having an aromatic structure, cyclohexanedimethanol type epoxy resins having an aromatic structure, naphthylene ether type epoxy resins, trimethylol type epoxy resins having an aromatic structure, and tetraphenylethane type epoxy resins having an aromatic structure.

[0038] The (A) curable resin preferably contains an epoxy resin having two or more epoxy groups per molecule as the epoxy resin. The proportion of the epoxy resin having two or more epoxy groups per molecule relative to 100% by mass of the non-volatile components of the epoxy resin is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

[0039] Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). The resin composition may contain only a liquid epoxy resin as the epoxy resin, or may contain only a solid epoxy resin, or may contain a combination of a liquid epoxy resin and a solid epoxy resin.

[0040] The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups in one molecule.

[0041] Preferred liquid epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, and epoxy resins having a butadiene structure.

[0042] Specific examples of liquid epoxy resins include "HP4032," "HP4032D," and "HP4032SS" (naphthalene-type epoxy resins) manufactured by DIC Corporation; "828US," "828EL," "jER828EL," "825," and "Epikote 828EL" (bisphenol A-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER807" and "1750" (bisphenol F-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolac-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630," "630LSD," and "604" (glycidylamine-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "ED-523T" (glycirol-type epoxy resin) manufactured by ADEKA Corporation; and "EP-3950L" and "EP-3980S" manufactured by ADEKA Corporation. Examples of epoxy resins include glycidylamine epoxy resins (EP-4088S, manufactured by ADEKA Corporation; ZX1059, manufactured by Nippon Steel Chemical & Material Co., Ltd.; a mixture of bisphenol A and bisphenol F epoxy resins (EX-721, manufactured by Nagase ChemteX Corporation; CELLOXIDE 2021P, manufactured by Daicel Corporation; PB-3600, manufactured by Daicel Corporation; JP-100 and JP-200, manufactured by Nippon Soda Co., Ltd.; and ZX1658 and ZX1658GS, manufactured by Nippon Steel Chemical & Material Co., Ltd., as liquid 1,4-glycidylcyclohexane epoxy resins. These may be used alone or in combination.

[0043] 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.

[0044] Preferred solid epoxy resins include bixylenol-type epoxy resins, naphthalene-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, naphthol novolac-type epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol AF-type epoxy resins, phenol aralkyl-type epoxy resins, tetraphenylethane-type epoxy resins, and phenolphthalimidine-type epoxy resins.

[0045] Specific examples of solid epoxy resins include "HP4032H" (naphthalene type epoxy resin) manufactured by DIC Corporation; "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resins) manufactured by DIC Corporation; "N-690" (cresol novolac type epoxy resin) manufactured by DIC Corporation; "N-695" (cresol novolac type epoxy resin) manufactured by DIC Corporation; "HP-7200", "HP-7200HH", "HP-7200H", and "HP-7200L" (dicyclopentadiene type epoxy resins) manufactured by DIC Corporation; and "EXA-7311" and "E" manufactured by DIC Corporation. XA-7311-G3, EXA-7311-G4, EXA-7311-G4S, HP6000 (naphthylene ether type epoxy resin); Nippon Kayaku's EPPN-502H (trisphenol type epoxy resin); Nippon Kayaku's NC7000L (naphthol novolac type epoxy resin); Nippon Kayaku's NC3000H, NC3000, NC3000L, NC3000FH, NC3100 (biphenyl type epoxy resin); Nippon Steel Chemical & Material's ESN475V, ESN4100V (Naphthalene-type epoxy resin); "ESN485" (naphthol-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN375" (dihydroxynaphthalene-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YX4000HK", and "YL7890" (bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL6121" (biphenyl-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX7700" (f phenol aralkyl type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals Co., Ltd.; "YL7760" and "YX7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation; and "WHR991S" (phenolphthalimidine type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.These may be used alone or in combination of two or more.

[0046] When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin, the mass ratio thereof (liquid epoxy resin:solid epoxy resin) is preferably 20:1 to 1:20, more preferably 10:1 to 1:10, and particularly preferably 7:1 to 1:7.

[0047] The epoxy equivalent 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. The epoxy equivalent represents the mass of the resin per equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0048] The weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight average molecular weight of the resin can be measured by gel permeation chromatography (GPC) as a polystyrene-equivalent value.

[0049] The amount of epoxy resin in the resin composition is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 5% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 35% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

[0050] The amount of epoxy resin in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, particularly preferably 20% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, particularly preferably 70% by mass or less, when the resin components in the resin composition are taken as 100% by mass. Unless otherwise specified, the resin components of the resin composition refer to the non-volatile components of the resin composition excluding the inorganic filler (B) described below.

[0051] The phenolic resin may be a compound having one or more, preferably two or more, hydroxyl groups bonded to an aromatic ring such as a benzene ring or a naphthalene ring per molecule. Phenolic resins are sometimes called "phenolic curing agents" because, when combined with an epoxy resin, they react with the epoxy resin to cure the resin composition. Phenolic resins having a novolac structure are preferred from the viewpoint of obtaining a cured product with excellent heat resistance and water resistance. Furthermore, from the viewpoint of obtaining a cured product with excellent adhesion to the conductor layer, nitrogen-containing phenolic resins are preferred, and triazine skeleton-containing phenolic resins are more preferred. Among these, triazine skeleton-containing phenolic novolac resins are preferred from the viewpoint of obtaining a cured product with excellent heat resistance, water resistance, and adhesion. Specific examples of phenolic resins include "MEH-7700," "MEH-7810," and "MEH-7851" manufactured by Meiwa Chemical Industry Co., Ltd.; "NHN," "CBN," and "GPH" manufactured by Nippon Kayaku Co., Ltd.; "SN-170," "SN-180," "SN-190," "SN-475," "SN-485," "SN-495," "SN-375," and "SN-395" manufactured by Nippon Steel Chemical & Material Co., Ltd.; and "LA-7052," "LA-7054," "LA-3018," "LA-3018-50P," "LA-1356," "TD2090," and "TD-2090-60M" manufactured by DIC Corporation.

[0052] As the activated ester resin, compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are generally preferred. When combined with an epoxy resin, activated ester resins react with the epoxy resin to cure the resin composition, and are therefore sometimes referred to as "activated ester curing agents." The activated ester resin is preferably one obtained by the condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound. From the perspective of obtaining a cured product with excellent heat resistance, activated ester resins obtained from a carboxylic acid compound and a hydroxy compound are preferred, and activated ester resins obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound are more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalene, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolak. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by condensing one dicyclopentadiene molecule with two phenol molecules.

[0053] Specifically, the active ester resin is preferably a dicyclopentadiene-type active ester resin, a naphthalene-type active ester resin containing a naphthalene structure, an active ester resin containing an acetylated product of phenol novolac, or an active ester resin containing a benzoylated product of phenol novolac, and among these, at least one selected from a dicyclopentadiene-type active ester resin and a naphthalene-type active ester resin is more preferred. As the dicyclopentadiene-type active ester resin, an active ester resin containing a dicyclopentadiene-type diphenol structure is preferred.

[0054] Commercially available activated ester resins include, for example, activated 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," "HPC-8000H," and "HPC-8000H-65TM" (manufactured by DIC Corporation); and activated ester resins containing a naphthalene structure such as "HP-B-8151-62T," "EXB-8100L-65T," "EXB-8150-60T," and "EXB-815 Examples of activated ester resins include "EXB-9416-70BK", "HPC-8150-60T", "HPC-8150-62T", and "EXB-8" (manufactured by DIC Corporation); an activated ester resin containing phosphorus, such as "EXB9401" (manufactured by DIC Corporation); an activated ester resin which is an acetylated product of phenol novolac, such as "DC808" (manufactured by Mitsubishi Chemical Corporation); an activated ester resin which is a benzoylated product of phenol novolac, such as "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation); and an activated ester resin containing a styryl group and a naphthalene structure, such as "PC1300-02-65MA" (manufactured by Air Water Inc.).

[0055] The cyanate resin may be a compound having one or more, preferably two or more, cyanate groups in one molecule. When combined with an epoxy resin, the cyanate resin reacts with the epoxy resin to cure the resin composition, and therefore is sometimes called a "cyanate-based curing agent." Examples of cyanate resins include bifunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate)), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, and bis(4-cyanatephenyl)ether; multifunctional cyanate resins derived from phenol novolac and cresol novolac; and prepolymers in which these cyanate resins are partially converted to triazine. Specific examples of cyanate resins include "PT30" and "PT60" manufactured by Lonza Japan (both of which are phenol novolac-type multifunctional cyanate resins), "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate has been triazine-converted to form a trimer).

[0056] As the carbodiimide resin, a compound having one or more, preferably two or more, carbodiimide structures in one molecule can be used. When combined with an epoxy resin, a carbodiimide resin can react with the epoxy resin to cure the resin composition, and therefore is sometimes called a "carbodiimide-based curing agent." Specific examples of carbodiimide resins include aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexane-bis(methylene-t-butylcarbodiimide); aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylenebiscyclohexylenecarbodiimide), and poly(isophoronecarbodiimide); poly(phenylenecarbodiimide), poly(naphthalenecarbodiimide); Examples of polycarbodiimides include aromatic polycarbodiimides such as poly(methylenediphenylenecarbodiimide), poly(tolylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylenediphenylenecarbodiimide), and poly[methylenebis(methylphenylene)carbodiimide]. Commercially available carbodiimide resins include, for example, "Carbodilite V-02B," "Carbodilite V-03," "Carbodilite V-04K," "Carbodilite V-07," and "Carbodilite V-09" manufactured by Nisshinbo Chemical Inc.; and "Stavaxol P," "Stavaxol P400," and "Hykasil 510" manufactured by Rhein Chemie.

[0057] As the acid anhydride resin, a compound having one or more, preferably two or more, acid anhydride groups in one molecule can be used. When combined with an epoxy group, the acid anhydride resin can react with the epoxy resin to cure the resin composition, and therefore is sometimes called an "acid anhydride curing agent." 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-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic anhydride. Examples of suitable anhydrides include hydrates, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymeric anhydrides such as styrene-maleic acid resin, which is a copolymer of styrene and maleic acid. Commercially available acid anhydride resins include, for example, "HNA-100," "MH-700," "MTA-15," "DDSA," and "OSA" manufactured by New Japan Chemical Co., Ltd.; "YH-306" and "YH-307" manufactured by Mitsubishi Chemical Corporation; "HN-2200" and "HN-5500" manufactured by Hitachi Chemical Co., Ltd.; and "EF-30," "EF-40," "EF-60," and "EF-80" manufactured by Clay Valley.

[0058] The amine resin may be a compound having one or more, preferably two or more, amino groups in one molecule. When combined with an epoxy group, the amine resin may react with the epoxy resin to cure the resin composition, and is therefore sometimes referred to as an "amine-based curing agent." Examples of the amine resin include aliphatic amines, polyether amines, alicyclic amines, and aromatic amines, with aromatic amines being preferred. The amine resin is preferably a primary amine or secondary amine, with primary amines being more preferred. Specific examples of amine resins include 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, and 2,2-bis(3-amino-4-hydroxyphenyl)propionate. Examples of suitable bis(4-aminophenoxy)benzene include bis(4-aminophenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, and bis(4-(3-aminophenoxy)phenyl)sulfone. Commercially available amine resins include, for example, "SEIKACURE-S" manufactured by Seika Corporation; "KAYABOND C-200S," "KAYABOND C-100," "KAYAHARD AA," "KAYAHARD AB," and "KAYAHARD AS" manufactured by Nippon Kayaku Co., Ltd.; "Epicure W" manufactured by Mitsubishi Chemical Corporation; and "DTDA" manufactured by Sumitomo Seika Chemicals Co., Ltd.

[0059] Benzoxazine resins, when combined with epoxy resins, can react with the epoxy resin to cure the resin composition, and are therefore sometimes called "benzoxazine-based curing agents." Specific examples of benzoxazine resins include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Corporation; "HFB2006M" manufactured by Showa Polymer Co., Ltd.; and "Pd" and "Fa" manufactured by Shikoku Chemical Industry Co., Ltd.

[0060] Thiol resins are sometimes called "thiol-based curing agents" because they react with epoxy resins when combined with them to cure the resin composition. Examples of thiol resins include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris(3-mercaptopropyl)isocyanurate.

[0061] The active group equivalent of the curing agent is preferably 50 g / eq. to 3000 g / eq., more preferably 100 g / eq. to 1000 g / eq., still more preferably 100 g / eq. to 500 g / eq., and particularly preferably 100 g / eq. to 300 g / eq. The active group equivalent is the mass of the curing agent per equivalent of the active group.

[0062] When the number of epoxy groups in the epoxy resin is taken as 1, the number of active groups in the curing agent is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, and preferably 5.0 or less, more preferably 4.0 or less, and particularly preferably 3.0 or less. The "number of epoxy groups in the epoxy resin" refers to the total value obtained by dividing the mass of the non-volatile components of the epoxy resin present in the resin composition by the epoxy equivalent. Furthermore, the "number of active groups in the curing agent" refers to the total value obtained by dividing the mass of the non-volatile components of the curing agent present in the resin composition by the active group equivalent.

[0063] The amount of curing agent in the resin composition is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 5% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 30% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

[0064] The amount of the curing agent in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 20% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, and particularly preferably 70% by mass or less, when the resin component in the resin composition is 100% by mass.

[0065] The radical polymerizable resin may be a compound having an ethylenically unsaturated bond. Therefore, the radical polymerizable resin may have a radical polymerizable group containing an ethylenically unsaturated bond. Examples of the radical polymerizable group include unsaturated hydrocarbon groups such as vinyl, allyl, 3-cyclohexenyl, 3-cyclopentenyl, 2-vinylphenyl, 3-vinylphenyl, and 4-vinylphenyl; and α,β-unsaturated carbonyl groups such as acryloyl, methacryloyl, and maleimide (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl) groups. The number of radical polymerizable groups contained in one molecule of the radical polymerizable resin may be one, but preferably two or more. One type of radical polymerizable resin may be used alone, or two or more types may be used in combination.

[0066] Examples of radical polymerizable resins include (meth)acrylic radical polymerizable resins, styrene radical polymerizable resins, allyl radical polymerizable resins, and maleimide radical polymerizable resins.

[0067] The (meth)acrylic radical polymerizable resin is, for example, a compound having one or more, preferably two or more, acryloyl groups and / or methacryloyl groups. Examples of the (meth)acrylic radical polymerizable resin 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, 1,9-nonane diol di(meth)acrylate, and the like. 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; dioxane glycol di(meth)acrylate, 3,6-dioxa-1,8-octanediol di(meth)acrylate, ) 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, propoxylated bisphenol A di(meth)acrylate, and other low molecular weight (molecular weight less than 1000) ether-containing (meth)acrylic acid ester compounds; 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 isocyanuric acid tri(meth)acrylate; and high molecular weight (molecular weight 1000 or more) acrylic acid ester compounds such as (meth)acrylic-modified polyphenylene ether resins.Commercially available (meth)acrylic radical polymerizable resins include, for example, "A-DOG" (dioxane glycol diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., "DCP-A" (tricyclodecane dimethanol diacrylate) and "DCP" (tricyclodecane dimethanol dimethacrylate) manufactured by Kyoeisha Chemical Co., Ltd., "KAYARAD R-684" (tricyclodecane dimethanol diacrylate) and "KAYARAD R-604" (dioxane glycol diacrylate) manufactured by Nippon Kayaku Co., Ltd., and "SA9000" and "SA9000-111" (methacrylic-modified polyphenylene ether) manufactured by SABIC Innovative Plastics.

[0068] The styrene radical polymerizable resin is, for example, a compound having one or more, preferably two or more, vinyl groups directly bonded to an aromatic carbon atom. Examples of the styrene radical polymerizable resin 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 resin and styrene-divinylbenzene copolymer. Commercially available styrene-based radical polymerizable resins include, for example, "ODV-XET(X03)", "ODV-XET(X04)", and "ODV-XET(X05)" (styrene-divinylbenzene copolymers) manufactured by Nippon Steel Chemical & Material Co., Ltd., and "OPE-2St 1200" and "OPE-2St 2200" (vinylbenzyl-modified polyphenylene ether resins) manufactured by Mitsubishi Gas Chemical Company, Inc.

[0069] The allyl radical polymerizable resin is, for example, a compound having one or more, preferably two or more, allyl groups. Examples of allyl 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-naphthalenedicarboxylate, and diallyl 2,3-naphthalenecarboxylate; isocyanuric acid allyl ester compounds such as 1,3,5-triallyl isocyanurate and 1,3-diallyl-5-glycidyl isocyanurate; epoxy-containing aromatic allyl compounds such as 2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane; benzoxazine-containing aromatic allyl compounds such as bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane; ether-containing aromatic allyl compounds such as 1,3,5-triallyl ether benzene; and allyl silane compounds such as diallyldiphenylsilane. Commercially available allyl radical polymerizable resins include "TAIC" (1,3,5-triallyl isocyanurate) manufactured by Nippon Kasei Chemical Industry Co., Ltd., "DAD" (diallyl diphenate) manufactured by Nisshoku Techno Fine Chemical Co., Ltd., "TRIAM-705" (triallyl trimellitate) manufactured by Wako Pure Chemical Industries, Ltd., "DAND" (2,3-naphthalenecarboxylic acid diallyl) manufactured by Nippon Distillation Industry Co., Ltd., "ALP-d" (bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane) manufactured by Shikoku Chemical Industry Co., Ltd., "RE-810NM" (2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane) manufactured by Nippon Kayaku Co., Ltd., and "DA-MGIC" (1,3-diallyl-5-glycidyl isocyanurate) manufactured by Shikoku Chemical Industry Co., Ltd.

[0070] The maleimide radical polymerizable resin is, for example, a compound having one or more, preferably two or more, maleimide groups. The maleimide radical polymerizable resin may be an aliphatic maleimide compound containing an aliphatic amine skeleton, or an aromatic maleimide compound containing an aromatic amine skeleton. Commercially available maleimide radical polymerizable resins include, for example, "SLK-2600" manufactured by Shin-Etsu Chemical Co., Ltd.; "BMI-1500," "BMI-1700," "BMI-3000J," "BMI-689," and "BMI-2500" (dimer diamine structure-containing maleimide compounds) manufactured by Designer Molecules, Inc.; "BMI-6100" (aromatic maleimide compound) manufactured by Designer Molecules, Inc.; "MIR-5000-60T" and "MIR-3000-70MT" (biphenylaralkyl maleimide compounds) manufactured by Nippon Kayaku Co., Ltd.; "BMI-70" and "BMI-80" manufactured by K.I. Chemical Industry Co., Ltd.; and "BMI-2300" and "BMI-TMH" manufactured by Daiwa Chemical Industry Co., Ltd. Furthermore, as the maleimide-based radical polymerizable resin, a maleimide resin (maleimide compound containing an indane ring skeleton) disclosed in the Japan Institute of Invention and Innovation's Disclosure Technical Bulletin No. 2020-500211 may be used.

[0071] Furthermore, as the radical polymerizable resin, those described in the section on photocurable resins may be used.

[0072] The ethylenically unsaturated bond 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 ethylenically unsaturated bond equivalent represents the mass of the radical polymerizable resin per equivalent of ethylenically unsaturated bonds.

[0073] 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 can be, for example, 150 or more.

[0074] The amount of the radical polymerizable resin in the resin composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 1% by mass or more, and is preferably 15% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less, when the non-volatile components in the resin composition are taken as 100% by mass.

[0075] The amount of the radical polymerizable resin in the resin composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 1% by mass or more, and is preferably 15% by mass or less, more preferably 10% by mass or less, and particularly preferably 8% by mass or less, when the resin component in the resin composition is 100% by mass.

[0076] The photocurable resin may be a resin that can be cured when exposed to light. Examples of the photocurable resin include radical polymerizable resins. One type of photocurable resin may be used alone, or two or more types may be used in combination.

[0077] The radical polymerizable resin as the photocurable resin may be any of those described in the section on thermosetting resins. From the viewpoint of enabling development with an alkaline developer, the radical polymerizable resin as the photocurable resin is preferably a resin having an ethylenically unsaturated bond and a carboxyl group.

[0078] A resin having an ethylenically unsaturated bond and a carboxyl group may have a combination of a radically polymerizable group containing an ethylenically unsaturated bond and a carboxyl group. Examples of the radically polymerizable group include those mentioned above. Among them, a (meth)acryloyl group is preferred. The number of radically polymerizable groups per resin molecule may be one or two or more. When a resin contains two or more radically polymerizable groups per molecule, the radically polymerizable groups may be the same or different. Furthermore, the number of carboxyls per resin molecule may be one or two or more.

[0079] The resin having an ethylenically unsaturated bond and a carboxyl group preferably contains a naphthalene skeleton. The resin having an ethylenically unsaturated bond and a carboxyl group may contain one naphthalene skeleton or two or more naphthalene skeletons in one molecule. The resin having an ethylenically unsaturated bond and a carboxyl group preferably has two or less radical polymerizable groups per naphthalene skeleton. The radical polymerizable group is preferably contained in a substituent of the naphthalene skeleton. The resin having an ethylenically unsaturated bond and a carboxyl group preferably has two or less carboxyl groups per naphthalene skeleton. The carboxyl group is preferably contained in a substituent of the naphthalene skeleton.

[0080] From the viewpoint of film-forming properties, the weight-average molecular weight of the resin having an ethylenically unsaturated bond and a carboxyl group is preferably 500 or more, more preferably 1000 or more, even more preferably 1500 or more, and particularly preferably 2000 or more. From the viewpoint of developability, the upper limit is preferably 10000 or less, more preferably 8000 or less, and even more preferably 7500 or less.

[0081] From the viewpoint of keeping the solubility in an alkaline developer within an appropriate range, the acid value of the resin having an ethylenically unsaturated bond and a carboxyl group is preferably 0.1 mgKOH / g or more, more preferably 0.5 mgKOH / g or more, particularly preferably 1 mgKOH / g or more, and is preferably 150 mgKOH / g or less, more preferably 120 mgKOH / g or less, particularly preferably 100 mgKOH / g or less.

[0082] The amount of the radical polymerizable resin as the photocurable resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

[0083] The amount of the radical polymerizable resin as the photocurable resin is preferably 20% by mass or more, more preferably 30% by mass or more, and particularly preferably 40% by mass or more, and is preferably 80% by mass or less, more preferably 70% by mass or less, and particularly preferably 65% ​​by mass or less, when the resin component in the resin composition is 100% by mass.

[0084] The amount of (A) curable resin in the resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, and particularly preferably 10% by mass or more, and is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

[0085] The amount of (A) curable resin in the resin composition is preferably 60% by mass or more, more preferably 70% by mass or more, and particularly preferably 80% by mass or more, and is preferably 97% by mass or less, more preferably 96% by mass or less, and particularly preferably 95% by mass or less, when the resin components in the resin composition are taken as 100% by mass.

[0086] The resin composition may contain (B) an inorganic filler as an optional component. (B) The inorganic filler is usually contained in the resin composition in the form of particles.

[0087] (B) Inorganic fillers are inorganic compounds. Examples of (B) inorganic filler materials include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium titanate zirconate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica and alumina are preferred, and silica is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Spherical silica is preferred. The (B) inorganic filler may be used alone or in combination of two or more.

[0088] (B) Examples of commercially available inorganic fillers include "SP60-05" and "SP507-05" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YC100C", "YA050C", "YA050C-MJE", "YA010C", "SC2500SQ", "SO-C4", "SO-C2", "SO-C1", and "SC2050-SXF" manufactured by Admatechs Co., Ltd.; "UFP-30" manufactured by Denka Company Limited; and "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" manufactured by Tokuyama Corporation.

[0089] The average particle size of the (B) inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, particularly preferably 0.1 μm or more, and preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less. The average particle size of the (B) inorganic filler can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, a volumetric particle size distribution of the inorganic filler is prepared using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is used as the average particle size. A measurement sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing the mixture ultrasonically for 10 minutes. The volumetric particle size distribution of the inorganic filler is measured using a laser diffraction particle size distribution analyzer with blue and red wavelength light sources using a flow cell system, and the average particle size can be calculated as the median diameter from the particle size distribution obtained. Examples of laser diffraction particle size distribution analyzers include the LA-960 manufactured by Horiba, Ltd.

[0090] (B) The specific surface area of ​​the inorganic filler is preferably 1 m 2 / g or more, more preferably 2m 2 / g or more, particularly preferably 3m 2 / g or more, preferably 60m 2 / g or less, more preferably 50m 2 / g or less, particularly preferably 40m 2 The specific surface area can be measured in accordance with the BET method by adsorbing nitrogen gas onto the surface of a sample using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) and calculating the specific surface area using the BET multipoint method.

[0091] (B) The inorganic filler is preferably treated with a surface treatment agent from the viewpoint of improving moisture resistance and dispersibility. Examples of the surface treatment agent include a fluorine-containing silane coupling agent, an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an alkoxysilane, an organosilazane compound, and a titanate coupling agent. One type of surface treatment agent may be used alone, or two or more types may be used in any combination.

[0092] Examples of commercially available surface treatment agents include Shin-Etsu Chemical Co., Ltd.'s "KBM403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM803" (3-mercaptopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent), and Shin-Etsu Chemical Co., Ltd.'s "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane).

[0093] The degree of surface treatment with the surface treatment agent preferably falls within a specific range from the viewpoint of improving the dispersibility of (B) the inorganic filler. Specifically, 100% by mass of the inorganic filler is preferably surface-treated with 0.2% to 5% by mass of the surface treatment agent, more preferably with 0.2% to 3% by mass of the surface treatment agent, and even more preferably with 0.3% to 2% by mass of the surface treatment agent.

[0094] The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of ​​the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of ​​the inorganic filler is set to 0.02 mg / m 2 More than 0.1 mg / m is preferable. 2More preferably, 0.2 mg / m or more 2 On the other hand, from the viewpoint of suppressing an increase in the melt viscosity of the resin composition, it is more preferable that the content be 1.0 mg / m 2 Less than 0.8 mg / m is preferred 2 Less than 0.5 mg / m is more preferable. 2 The following is even more preferred:

[0095] (B) The amount of carbon per unit surface area of ​​the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solid content, the amount of carbon per unit surface area of ​​the inorganic filler can be measured using a carbon analyzer. The carbon analyzer that can be used is the "EMIA-320V" manufactured by Horiba, Ltd.

[0096] The amount of (B) inorganic filler in the resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, particularly preferably 40% by mass or more, relative to 100% by mass of the non-volatile components of the resin composition, and is preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, particularly preferably 80% by mass or less.

[0097] The resin composition may contain, as an optional component, a curing accelerator (C), which functions as a curing catalyst that accelerates the curing of the curable resin (A).

[0098] The (C) curing accelerator may be an appropriate one depending on the type of (A) curable resin. For example, when the (A) curable resin contains an epoxy resin, examples of the (C) curing accelerator that can accelerate the curing of the epoxy resin include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, and amine-based curing accelerators. One type of (C) curing accelerator may be used alone, or two or more types may be used in combination.

[0099] Examples of the phosphorus-based curing accelerator include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitate, tetrabutylphosphonium hydrogenhexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butyldimethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, and tetraphenylphosphonium tetra-p-tolylborate. aromatic phosphonium salts such as tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone adducts such as triphenylphosphine-p-benzoquinone adduct; aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine;Dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine aromatic phosphines such as benzene, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, and 2,2'-bis(diphenylphosphino)diphenyl ether;

[0100] Examples of the urea-based curing accelerator include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. aromatic dimethylureas such as toluene bis(dimethylurea), 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N',N'-dimethylurea), and N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluene bisdimethylurea].

[0101] Examples of guanidine curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

[0102] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-methylimidazole. Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl -(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct Examples of imidazole compounds include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins. Commercially available imidazole curing accelerators include "1B2PZ," "2E4MZ," "2MZA-PW," "2MZ-OK," "2MA-OK," "2MA-OK-PW," "2PHZ," "2PHZ-PW," "Cl1Z," "Cl1Z-CN," "Cl1Z-CNS," and "C11Z-A" manufactured by Shikoku Chemicals Corporation; and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

[0103] Examples of metal-based curing accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organic cobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organic copper complexes such as copper(II) acetylacetonate, organic zinc complexes such as zinc(II) acetylacetonate, organic iron complexes such as iron(III) acetylacetonate, organic nickel complexes such as nickel(II) acetylacetonate, and organic manganese complexes such as manganese(II) acetylacetonate. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0104] Examples of the amine curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc. Commercially available amine curing accelerators may be used, such as "MY-25" manufactured by Ajinomoto Fine-Techno Co., Inc.

[0105] The amount of (C) curing accelerator in the resin composition is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and particularly preferably 0.05% by mass or more, and is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, and particularly preferably 0.2% by mass or less, based on 100% by mass of the non-volatile components in the resin composition.

[0106] The amount of (C) curing accelerator in the resin composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and particularly preferably 0.10% by mass or more, and is preferably 2.0% by mass or less, more preferably 1.0% by mass or less, and particularly preferably 0.5% by mass or less, when the resin component in the resin composition is taken as 100% by mass.

[0107] The resin composition may contain a (D) thermoplastic resin as an optional component. Examples of the (D) thermoplastic resin include phenoxy resin, polyimide resin, polyvinyl acetal resin, polyolefin resin, polybutadiene resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polycarbonate resin, polyetheretherketone resin, and polyester resin. The (D) thermoplastic resin may be used alone or in combination of two or more.

[0108] Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A, bisphenol F, bisphenol S, bisphenolacetophenone, novolac, biphenyl, fluorene, dicyclopentadiene, norbornene, naphthalene, anthracene, adamantane, terpene, and trimethylcyclohexane. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Specific examples of phenoxy resins include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both of which are phenoxy resins containing a bisphenol A skeleton); "YX8100" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol S skeleton); "YX6954" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol acetophenone skeleton); "FX280" and "FX293" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YL7500BH30," "YX6954BH30," "YX7553," "YX7553BH30," "YL7769BH30," "YL6794," "YL7213," "YL7290," "YL7482," and "YL7891BH30" manufactured by Mitsubishi Chemical Corporation; and the like.

[0109] Specific examples of polyimide resins include "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., and "Rikacoat SN20" and "Rikacoat PN20" manufactured by New Japan Chemical Co., Ltd.

[0110] Examples of polyvinyl acetal resins include polyvinyl formal resins and polyvinyl butyral resins, with polyvinyl butyral resins being preferred. Specific examples of polyvinyl acetal resins include Denka Butyral 4000-2, Denka Butyral 5000-A, Denka Butyral 6000-C, and Denka Butyral 6000-EP, manufactured by Denki Kagaku Kogyo Co., Ltd.; and S-LEC BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, and BM series, manufactured by Sekisui Chemical Co., Ltd.

[0111] Examples of polyolefin resins include ethylene copolymer resins such as low-density polyethylene, very low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer; and polyolefin polymers such as polypropylene and ethylene-propylene block copolymer.

[0112] Examples of polybutadiene resins include hydrogenated polybutadiene skeleton-containing resins, hydroxy group-containing polybutadiene resins, phenolic hydroxy group-containing polybutadiene resins, carboxy group-containing polybutadiene resins, acid anhydride group-containing polybutadiene resins, epoxy group-containing polybutadiene resins, isocyanate group-containing polybutadiene resins, urethane group-containing polybutadiene resins, and polyphenylene ether-polybutadiene resins.

[0113] Specific examples of polyamide-imide resins include "Vylomax HR11NN" and "Vylomax HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of polyamide-imide resins also include modified polyamide-imides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamide-imides) manufactured by Hitachi Chemical Co., Ltd.

[0114] A specific example of the polyethersulfone resin is "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

[0115] Specific examples of polysulfone resins include polysulfones "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

[0116] A specific example of the polyphenylene ether resin is NORYL SA90 manufactured by SABIC, etc. A specific example of the polyetherimide resin is ULTEM manufactured by GE, etc.

[0117] Examples of polycarbonate resins include hydroxyl group-containing carbonate resins, phenolic hydroxyl group-containing carbonate resins, carboxyl group-containing carbonate resins, acid anhydride group-containing carbonate resins, isocyanate group-containing carbonate resins, and urethane group-containing carbonate resins. Specific examples of polycarbonate resins include "FPC0220" manufactured by Mitsubishi Gas Chemical Company, Inc., "T6002" and "T6001" (polycarbonate diols) manufactured by Asahi Kasei Chemicals Corporation, and "C-1090," "C-2090," and "C-3090" (polycarbonate diols) manufactured by Kuraray Co., Ltd. Specific examples of polyether ether ketone resins include "Sumiploy K" manufactured by Sumitomo Chemical Co., Ltd.

[0118] Examples of polyester resins include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, and polycyclohexane dimethyl terephthalate resin.

[0119] The weight average molecular weight (Mw) of the (D) thermoplastic resin is preferably greater than 5,000, more preferably 8,000 or more, even more preferably 10,000 or more, and particularly preferably 20,000 or more, and is preferably 100,000 or less, more preferably 70,000 or less, even more preferably 60,000 or less, and particularly preferably 50,000 or less.

[0120] The amount of (D) thermoplastic resin in the resin composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 1% by mass or more, and is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less, based on 100% by mass of the non-volatile components in the resin composition.

[0121] The amount of (D) thermoplastic resin in the resin composition is preferably 0.1% by mass or more, more preferably 1% by mass or more, and particularly preferably 2% by mass or more, and is preferably 30% by mass or less, more preferably 20% by mass or less, and particularly preferably 10% by mass or less, when the resin components in the resin composition are taken as 100% by mass.

[0122] In addition to the components (A) to (D), the resin composition may further contain an optional additive (E) as an optional non-volatile component. Examples of the optional additive (E) include organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone leveling agents and acrylic polymer leveling agents; thickeners such as bentone and montmorillonite; antifoaming agents such as silicone antifoaming agents, acrylic antifoaming agents, fluorine-based antifoaming agents, and vinyl resin antifoaming agents; ultraviolet absorbers such as benzotriazole ultraviolet absorbers; adhesion improvers such as urea silanes; adhesion promoters such as triazole adhesion promoters, tetrazole adhesion promoters, and triazine adhesion promoters; and antioxidants such as hindered phenol antioxidants. flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide); dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic anhydride-based stabilizers; polymerization initiation aids such as tertiary amines; photosensitizers such as pyrarizones, anthracenes, coumarins, xanthones, and thioxanthones; and organic particles. (E) The optional additives may be used alone or in combination of two or more.

[0123] The resin composition may further contain a (F) solvent as an optional volatile component in addition to the non-volatile components (A) to (E) described above. An organic solvent is typically used as the (F) solvent. Examples of the organic solvent include ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether-based solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, and anisole; alcohol-based solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples of suitable solvents include ether ester solvents such as ethyl acetate; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. (F) Solvents may be used singly or in combination of two or more.

[0124] The amount of (F) solvent is not particularly limited, but when all components in the resin composition are taken as 100% by mass, it 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, 10% by mass or less, or may even be 0% by mass.

[0125] The resin composition layer is usually used to obtain a cured product as a material for a circuit board, such as an insulating layer. Usually, volatile components such as the solvent (F) contained in the resin composition can be volatilized by the heat applied during curing, but nonvolatile components such as components (A) to (E) do not volatilize by the heat applied during curing. Therefore, the cured product can contain the nonvolatile components of the resin composition or their reaction products.

[0126] The cured product of the resin composition preferably has excellent dielectric properties. Specifically, the cured product of the resin composition preferably has a low relative dielectric constant. In one example, the relative dielectric constant of the cured product is preferably 5 or less, more preferably 4 or less, and particularly preferably 3 or less. There is no particular restriction on the lower limit, and it can be, for example, 1.5 or more, 2.0 or more, etc.

[0127] Furthermore, it is preferable that the cured product of the resin composition has a low dielectric loss tangent. For example, the dielectric loss tangent of the cured product is preferably 0.05 or less, more preferably 0.04 or less, and particularly preferably 0.03 or less. There is no particular lower limit, and it can be, for example, 0.001 or more, 0.002 or more, etc.

[0128] When the resin composition is thermosetting, the dielectric constant and the dielectric loss tangent can be measured using a cured product obtained by thermally curing the resin composition at 180°C for 90 minutes. When the resin composition is photocurable, the dielectric constant and the dielectric loss tangent can be measured using a cured product obtained by thermally curing the resin composition at 180°C for 90 minutes. 2 After irradiating the cured product with ultraviolet light, the product is heated at 180°C for 90 minutes to obtain a cured product. The dielectric constant and dielectric loss tangent of the cured product can be measured by the cavity resonance perturbation method at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C.

[0129] From the viewpoint of detecting defects by optical observation, the resin composition layer is preferably transparent to light of a wavelength used in optical observation. In this case, the resin composition layer is preferably transparent to light to an extent that defects contained in the resin composition layer can be detected. Since optical observation is usually performed using visible light, the resin composition layer is preferably transparent or translucent to visible light.

[0130] The thickness of the resin composition layer can be set depending on the application of the resin composition layer. Specifically, the thickness of the resin composition layer is preferably 200 μm or less, more preferably 70 μm or less, and particularly preferably 50 μm or less. The lower limit of the thickness of the resin composition layer is not particularly limited, but may be 5 μm or more, 10 μm or more, etc.

[0131] [Optional layers that may be provided on the resin sheet] The resin sheet may have an optional layer in combination with the support and the resin composition layer. An example of the optional layer is a protective film conforming to the support, which is provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. The protective film can prevent foreign matter such as dust from adhering to the surface of the resin composition layer and prevent the resin composition layer from being scratched.

[0132] [Shape and dimensions of resin sheet] The shape of the resin sheet is not particularly limited. Therefore, the resin sheet may be a sheet in the form of individual sheets. However, from the viewpoint of enabling continuous production of the resin sheet and improving production efficiency, the resin sheet is preferably a long sheet. Unless otherwise specified, a long sheet refers to a sheet having a length that can be wound into a roll, and may be, for example, a sheet having a length 10 times or more the width.

[0133] The thickness of the resin sheet is not particularly limited, but is preferably in the range of 5 μm to 500 μm, and more preferably in the range of 10 μm to 300 μm. When a resin sheet having an optional layer such as a protective film is used, it is preferable that the thickness of the entire resin sheet including the optional layer is in the above range.

[0134] [Manufacturing method of resin sheet] The above-mentioned resin sheet is, for example, (i) forming a resin composition layer on a support; (ii) a step of simultaneously optically observing the support and the resin composition layer to detect defects; This manufacturing method will be described in detail below. This manufacturing method is preferably carried out in a clean room.

[0135] FIG. 1 is a front view schematically illustrating an example of a resin sheet manufacturing apparatus 1. As shown in FIG. 1, the manufacturing apparatus 1 illustrated in this example includes a layer forming apparatus 100 that forms a resin composition layer 20 on a support 10 to obtain a resin sheet 30 before defect detection, and a detection apparatus 200 that performs optical observation of the resin sheet 30 to detect defects. Hereinafter, the resin sheet 30 before defect detection in step (ii) may be referred to as the "inspection sheet" 30, and the resin sheet 40 after defect detection in step (ii) may be referred to as the "product sheet" 40. In addition, the example illustrated in FIG. 1 will be described using an example in which the support 10 is a long film. However, a sheet of support 10 may also be used.

[0136] In step (i), a resin composition layer 20 is formed on a support 10 to obtain an inspection sheet 30. Typically, the resin composition layer 20 is formed by a method including preparing a liquid (varnish-like) resin composition 50 and applying the resin composition 50 onto the support 10. For example, the liquid (varnish-like) resin composition 50 may be applied directly onto the support 10. Alternatively, for example, the non-volatile components of the resin composition 50 may be mixed with a solvent to prepare a liquid (varnish-like) resin composition 50, which may then be applied onto the support 10.

[0137] The resin composition 50 can be produced, for example, by mixing the components that can be contained in the resin composition 50. The components may be mixed partially or entirely at the same time, or may be mixed sequentially. The temperature may be appropriately set during the process of mixing each component, and thus heating and / or cooling may be performed temporarily or throughout. Furthermore, stirring or shaking may be performed during the process of mixing each component.

[0138] There is no limitation on the method for applying the resin composition 50, and application can be performed using an application device 110 such as a die coater. In the example shown in FIG. 1 , a roll 60 of the support 10 is attached to a dispenser 300. The support 10 is dispensed from the roll 60, transported in its length direction, and supplied to a layer forming apparatus 100. Then, the resin composition 50 is applied onto the support 10 by an application device 110 included in the layer forming apparatus 100, and a resin composition layer 20 is formed.

[0139] In step (i), drying may be performed after application of the resin composition 50, if necessary. Drying can remove the solvent contained in the resin composition layer 20. Drying may be performed, for example, by heating, blowing hot air, or other methods. The drying conditions are not particularly limited, but drying is typically performed so that the solvent content in the resin composition layer 20 is 10% by mass or less, preferably 5% by mass or less. Although this varies depending on the boiling point of the solvent, for example, when using a resin composition 50 containing 30% by mass to 60% by mass of solvent, drying may be performed at 50°C to 150°C for 3 to 10 minutes. FIG. 1 shows an example in which the resin composition layer 20 is dried using a drying device 120, such as an oven, provided in the layer forming apparatus 100.

[0140] As described above, step (i), which includes applying the resin composition 50 onto the support 10 and, if necessary, drying it, is performed in the layer forming apparatus 100 to obtain an inspection sheet 30 including the support 10 and the resin composition layer 20. Typically, this inspection sheet 30 includes only the support 10 and the resin composition layer 20, and therefore the surface 20U of the resin composition layer 20 is exposed. This inspection sheet 30 is sent to the detection apparatus 200.

[0141] When the inspection target sheet 30 is supplied to the detection device 200, the detection device 200 performs a step (ii) of simultaneously optically observing the support 10 and the resin composition layer 20 to detect defects. The optical observation in this step (ii) includes photographing the inspection target sheet 30 with the photographing unit 220 while illuminating the inspection target sheet 30 with light from the light source unit 210. When the inspection target sheet 30 is photographed, the support 10 and the resin composition layer 20 provided on the inspection target sheet 30 are also photographed at the same time, so that optical observation of the support 10 and the resin composition layer 20 is performed simultaneously.

[0142] Optical observation is preferably performed by transmission observation. Transmission observation refers to optical observation performed by placing the inspected sheet 30 between the light source unit 210 and the photographing unit 220. In transmission observation, light emitted from the light source unit 210 passes through the inspected sheet 30, and the transmitted light is photographed by the photographing unit 220 to obtain an image. In this case, the light emitted from the light source unit 210 may pass through the support 10 and the resin composition layer 20 in this order and be photographed by the photographing unit 220, or the light emitted from the light source unit 210 may pass through the resin composition layer 20 and the support 10 in this order and be photographed by the photographing unit 220.

[0143] The optical observation is usually performed using visible light. Therefore, it is preferable to use a light source unit 210 that can emit visible light. It is also preferable to use an imaging unit 220 that can capture visible light. Examples of the detection device 200 that includes such a light source unit 210 and imaging unit 220 include an automated optical inspection (AOI) system and an optical microscope. Here, as shown in FIG. 1, a detection device 200 that includes a light source unit 210, an imaging unit 220, and an output unit 230 will be described as an example.

[0144] The light source unit 210 is provided so as to be able to emit light for optical observation onto the inspection target sheet 30. Examples of the light source unit 210 include a light emitting diode, a linear tube fluorescent lamp, a halogen lamp, and a metal halide lamp, but other light sources may also be used.

[0145] The photographing unit 220 is provided so as to be able to photograph the inspection target sheet 30. As the photographing unit 220, for example, a CCD camera equipped with an image sensor such as a CCD sensor and a lens can be used, but other photographing devices may also be used.

[0146] The output unit 230 is provided so as to be able to output the video data obtained by the imaging unit 220. For example, a printer or a monitor can be used as the output unit 230. An interface such as an input / output terminal may also be used as the output unit 230 so as to enable output to a computer. For example, when an automatic visual inspection device is used as the detection device 200, the output unit 230 is provided so as to be able to output the video data to a video processing unit (not shown). The video processing unit includes a computer equipped with a processor such as a CPU and memories such as RAM and ROM, and is provided so as to be able to detect defects that may appear in the video data.

[0147] In step (ii), specifically, defect detection is performed as follows: In the detection device 200, the inspection target sheet 30 is illuminated by light emitted by the light source unit 210, and the illuminated inspection target sheet 30 is photographed by the photographing unit 220. The image data of the inspection target sheet 30 obtained by photographing is sent to the output unit 230 and output. By photographing the inspection target sheet 30, optical observation of the support 10 and the resin composition layer 20 is performed simultaneously. Then, the image data resulting from the optical observation shows both an image of the support 10 and an image of the resin composition layer 20.

[0148] Typically, the imaging conditions, such as the illuminance of the light emitted by the light source unit 210, the focal position of the lens of the imaging unit 220, and the number of pixels of the image sensor, are set so as to be able to capture images of defects in the resin composition layer 20. Therefore, images of defects in the resin composition layer 20 appear in the image data. Furthermore, since the inspected sheet 30 includes a support 10 in close proximity to the resin composition layer 20, images of defects in the support 10 may also appear in the image data. Therefore, defects in the support 10 and defects in the resin composition layer 20 can be detected from the image data.

[0149] By detecting defects as described above, defects such as foreign matter and air bubbles in the resin composition layer 20 that may cause cracks and hinder wiring formation can be detected as described below. Among the defects that can be detected from the image data, defects in the resin composition layer 20 may include defects that may cause cracks and hinder wiring formation. Therefore, defects in the resin composition layer that may cause cracks and hinder wiring formation can be detected from defects in the resin composition layer 20 that appear in the image data. Specifically, defects in the resin composition layer that may cause cracks and hinder wiring formation can be detected by detecting defects having a maximum diameter equal to or greater than a specific value. The specific value representing the threshold value of the maximum diameter of defects to be detected is usually set to 10 μm, but may also be set to another value greater than 10 μm, for example, any value in the range of 10 μm to 100 μm.

[0150] However, there is a possibility that defects in the support 10 may be detected from the image data. Defects in the support 10 do not indicate defects contained in the resin composition layer 20. Therefore, if many defects in the support 10 are included in the defects that can be detected from the image data, and all of the defects that can be detected from the image data are detected as defects in the resin composition layer 20, false detections will occur for the number of defects in the support 10. Conventionally, such false detections occurred frequently, resulting in low detection accuracy.

[0151] In contrast, the support 10 used in this embodiment has a small number of defects with a maximum diameter of 10 μm or more, and preferably does not include any defects with a maximum diameter of 10 μm or more. Therefore, the support 20 has few defects that could cause the above-mentioned false detection, and preferably does not have any defects that could cause false detection. Therefore, even if all defects that can be detected from the video data and have a maximum diameter of a specific value or more are detected as defects in the resin composition layer 20, the occurrence of false detection can be suppressed. Therefore, by detecting defects with a maximum diameter of a specific value or more from the video data as defects in the resin composition layer 20, it is possible to detect defects in the resin composition layer 20 that could cause cracks and hinder wiring formation with high accuracy.

[0152] In a preferred embodiment, an automated optical inspection (AOI) device is used as the detection device 200, and an image processing unit (not shown) detects defects in the resin composition layer 20 that may cause cracks or hinder wiring formation. For example, the image processing unit receives image data output from the output unit 230 and detects defects having a maximum diameter equal to or greater than a specific value from the image data. The image processing unit then determines that the position of the detected defect is the defect in the resin composition layer 20 that may cause cracks or hinder wiring formation, and outputs the position of the defect.

[0153] By detecting defects as described above, a product sheet 40 is obtained as a resin sheet for which defects have been detected. If the resin composition layer 20 contained in this product sheet 40 contains defects, the location of the defects is known. Therefore, by removing the product sheet 40 containing the defects or removing the portion containing the defects, a high-quality resin sheet product sheet 40 can be obtained that is free of defects in the resin composition layer 20 that could cause cracks or hinder wiring formation. Furthermore, the manufacturing method described above reduces the occurrence of erroneous detection of defects. Therefore, it is possible to prevent the erroneous removal of a resin sheet 40 with no defects in the resin composition layer 20, and also to prevent the erroneous removal of a portion of the resin sheet 40 that is free of defects. Therefore, it is possible to improve product yield.

[0154] Furthermore, the above-described manufacturing method makes it possible to accurately measure the number of defects in the resin composition layer 20 of the manufactured product sheet 40. Therefore, it is possible to grasp the defect level of the resin composition layer 20 with high precision, and therefore to achieve accurate quality evaluation of the product sheet 40.

[0155] The method for producing a resin sheet may further include any step in combination with the above-described steps (i) and (ii). The method for producing a resin sheet may include, for example, a step of removing from product sheet 40 the portion of resin composition layer 20 where a defect has been detected, as described above.

[0156] The method for producing a resin sheet may also include, for example, a step of laminating a protective film (not shown) to the surface 20U of the resin composition layer 20. The lamination of the protective film may be performed before step (ii), but from the viewpoint of highly accurate defect detection, it is preferable that the inspected sheet 30 in step (ii) comprises only the support 10 and the resin composition layer 20, and therefore does not comprise a protective film. Therefore, it is preferable that the lamination of the protective film is performed after step (ii).

[0157] Furthermore, the method for manufacturing a resin sheet may include, for example, a step of winding and recovering the product-film 40, a step of cutting the product-film 40 to a desired width, and the like.

[0158] The technical significance of the above-mentioned production method will be explained below, but the explanation of the technical significance given below does not limit the technical scope of the present invention.

[0159] In circuit boards manufactured using conventional resin sheets, the size of the formed wiring was large, so defects in the resin composition layer that could hinder wiring formation were large, measuring several hundred microns or more. Such large defects can be visually distinguished from defects in the support. Therefore, by visually distinguishing whether the defects in the resin sheet are defects in the resin composition layer or defects in the support, it was possible to accurately detect defects in the resin composition layer. Furthermore, supports used in the manufacture of resin sheets that do not have defects of several hundred microns or more were generally easily available on the market. For these reasons, defects in the support have not traditionally been considered a problem.

[0160] In response to this, in recent years, the miniaturization of wiring has progressed, and therefore the size of defects that can be tolerated in resin composition layers used to form insulating layers has become smaller. Specifically, it is desirable to eliminate defects with a maximum diameter of approximately several tens of micrometers from resin composition layers. Therefore, it is desirable to improve the defect detection level so that not only defects with a maximum diameter of several hundred micrometers or more can be detected, but also defects with a maximum diameter of approximately several tens of micrometers.

[0161] Defects with a maximum diameter of approximately several tens of micrometers are difficult to detect visually, and therefore detection is required using a detection device such as an automated optical inspection (AOI) or an optical microscope. When detecting defects using such a detection device, the support and the resin composition layer are simultaneously within the field of view of the imaging section of the detection device. However, when using a detection device, it is difficult to distinguish between defects in the support and defects in the resin composition layer, and therefore defects in the resin composition layer are frequently erroneously detected based on defects in the support. This type of erroneous detection is an issue that only became apparent as the miniaturization of wiring progressed and the detection of small defects on the order of several tens of micrometers became necessary.

[0162] Therefore, the present inventors attempted to use a support having fewer defects with a maximum diameter of 10 μm or more, which are difficult to distinguish from small defects in the resin composition layer that may hinder the formation of wiring. Examples of defects in the support include fragments of resin pellets used as the support material, various additives, and resin lumps generated during the support manufacturing process. These defects inevitably occur during the support manufacturing process. Therefore, it was determined that the number of defects with a maximum diameter of 10 μm or more was 5 / cm. 2 Supports with a density of less than 1000 nm are not easy to obtain, and it is particularly difficult to obtain them as long, large-area films. Therefore, it is desirable to select a support of a grade with few defects as the support described above, and more preferably to inspect the purchased support to identify any defective parts and remove those parts before use.

[0163] In this way, in one aspect, the manufacturing method described above can be said to solve a problem that first became apparent when applied to circuit boards that require finer wiring, by using a support that is not easily prepared. Therefore, the manufacturing method described above has made a significant contribution to circuit board manufacturing technology and is therefore highly valuable.

[0164] [Method for detecting defects in a resin composition layer] The method of step (ii) in the above-mentioned method for producing a resin sheet may be carried out as a method for detecting defects in the resin composition layer of the resin sheet. Therefore, the method of step (ii) may be carried out independently of step (i), or may be carried out in combination with any step other than step (i). The content of this defect detection method is as described in detail in the explanation of step (ii) in the method for producing a resin sheet. According to this defect detection method, defects in the resin composition layer of the resin sheet can be detected with high accuracy.

[0165] [Uses of resin sheets] The above-mentioned resin sheet can be suitably used, for example, as a resin sheet for forming an insulating layer (resin sheet for forming an insulating layer). In particular, the resin sheet is suitable as a resin sheet for forming an insulating layer of a circuit board such as a printed wiring board or a semiconductor chip package. In a particularly preferred example, the resin sheet is preferably used for forming an interlayer insulating layer of a multilayer printed wiring board. Furthermore, the resin sheet is preferably used for forming a rewiring formation layer. The rewiring formation layer refers to an insulating layer on which a rewiring layer is formed. Furthermore, the rewiring layer refers to a conductor layer formed on the rewiring formation layer as an insulating layer.

[0166] Furthermore, the above-described resin sheet may be used to form, for example, a solder resist, an underfill material, a die bonding material, a semiconductor sealing material, a hole filling resin, or a component embedding resin.

[0167] As an example of the use of the resin sheet, a method for manufacturing a printed wiring board using the resin sheet will be described below. A printed wiring board usually has an insulating layer obtained by curing a resin composition layer. This printed wiring board can be manufactured, for example, using the above-mentioned resin sheet by a method including the following steps (I) and (II). (I) A step of laminating a resin sheet on an inner layer substrate so that the resin composition layer of the resin sheet is bonded to the inner layer substrate. (II) A step of curing the resin composition layer to form an insulating layer.

[0168] The "inner layer substrate" used in step (I) is a member that will become the substrate of a printed wiring board, and examples thereof include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The substrate may have a conductor layer on one or both sides, and this conductor layer may be patterned. An inner layer substrate having a conductor layer (circuit) formed on one or both sides of the substrate is sometimes called an "inner layer circuit board." Furthermore, intermediate products on which an insulating layer and / or a conductor layer is to be further formed during the production of a printed wiring board are also included in the aforementioned "inner layer substrate." When the printed wiring board is a circuit board with built-in components, an inner layer substrate with built-in components may be used.

[0169] The inner layer substrate and the resin sheet can be laminated, for example, by thermocompression bonding the resin sheet to the inner layer substrate from the support side. Examples of a member for thermocompression bonding the resin sheet to the inner layer substrate (hereinafter also referred to as a "thermocompression bonding member") include a heated metal plate (such as a SUS end plate) or a metal roll (SUS roll). Note that rather than pressing the thermocompression bonding member directly onto the resin sheet, it is preferable to press it via an elastic material such as heat-resistant rubber so that the resin sheet can sufficiently conform to the surface irregularities of the inner layer substrate.

[0170] The lamination of the inner layer substrate and the resin sheet may be carried out by a vacuum lamination method. In the vacuum lamination method, the thermocompression temperature is preferably in the range of 60°C to 160°C, more preferably 80°C to 140°C, the thermocompression pressure is preferably in the range of 0.098MPa to 1.77MPa, more preferably 0.29MPa to 1.47MPa, and the thermocompression time is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. The lamination is preferably carried out under reduced pressure conditions of 26.7hPa or less.

[0171] The lamination can be performed using a commercially available vacuum laminator, such as a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nikko Materials Co., Ltd., or a batch vacuum pressure laminator.

[0172] After lamination, the laminated resin sheets may be smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression member from the support side. The pressing conditions for the smoothing treatment may be the same as the thermocompression conditions for lamination. The smoothing treatment may be performed using a commercially available laminator. Note that lamination and smoothing treatment may be performed consecutively using the commercially available vacuum laminator.

[0173] The support may be removed between step (I) and step (II), or may be removed after step (II).

[0174] In step (II), the resin composition layer is cured to form an insulating layer made of a cured product of the resin composition. The resin composition layer can be cured by a method suitable for the resin composition, such as thermal curing or photocuring. Specific curing conditions for the resin composition layer may be those typically used when forming an insulating layer for a printed wiring board.

[0175] For example, when a thermosetting resin composition, such as a resin composition containing a thermosetting resin, is used, curing of the resin composition may proceed as thermal curing. Therefore, in this case, step (II) may include thermally curing the resin composition layer. The thermal curing conditions for the resin composition layer 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.

[0176] Furthermore, when the resin composition layer is thermally cured, the method for producing a printed wiring board preferably includes preheating the resin composition layer at a temperature lower than the curing temperature before the thermal curing. For example, prior to thermal curing of the resin composition layer, the resin composition layer may be preheated at a temperature of typically 50°C to 150°C, preferably 60°C to 140°C, and more preferably 70°C to 130°C for typically 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes.

[0177] On the other hand, when a photocurable resin composition, such as a resin composition containing a photocurable resin, is used, the curing of the resin composition may proceed as photocuring. Therefore, in this case, step (II) may include photocuring the resin composition layer. The photocuring conditions of the resin composition may vary depending on the type of resin composition. For example, the resin composition layer in the irradiated area may be photocured by an exposure treatment in which the resin composition layer is irradiated with actinic rays. Examples of actinic rays include ultraviolet rays, visible rays, electron beams, and X-rays, with ultraviolet rays being particularly preferred. The irradiation dose of ultraviolet rays is, for example, 10 mJ / cm. 2 ~1000mJ / cm 2 When a resin sheet provided with a support is used, exposure may be carried out through the support, or after the support has been peeled off.

[0178] In the exposure treatment, the resin composition layer may be irradiated with actinic rays through a mask having a pattern formed thereon. Exposure methods using a mask include a contact exposure method in which exposure is performed by bringing the mask into contact with the workpiece, and a non-contact exposure method in which exposure is performed using parallel light without contact, and either method may be used.

[0179] Step (II) may include carrying out a development treatment after the exposure treatment. The development treatment can remove the non-photocured portions (unexposed portions) to form a pattern in the cured layer. Development is usually carried out by wet development. In wet development, a safe, stable, and easy-to-use developer is used, such as an alkaline aqueous solution, a water-based developer, or an organic solvent. Of these, a development step using an alkaline aqueous solution is preferred. Examples of development methods that can be used include spraying, swing immersion, brushing, and scraping.

[0180] Furthermore, when the resin composition layer is photocured, a post-baking treatment may be carried out as necessary after the photocuring and development. Examples of the post-baking treatment include ultraviolet irradiation treatment using a high-pressure mercury lamp and heating treatment using a clean oven. The ultraviolet irradiation treatment is carried out, for example, at 0.05 J / cm 2 ~10J / cm 2 The heat treatment can be carried out, for example, preferably at 150°C to 250°C for 20 to 180 minutes, more preferably at 160°C to 230°C for 30 to 120 minutes.

[0181] When manufacturing a printed wiring board, the following steps may be further performed: (III) drilling holes in the insulating layer, (IV) roughening the insulating layer, and (V) forming a conductor layer. These steps (III) to (V) may be performed according to various methods known to those skilled in the art and used in manufacturing printed wiring boards. When the support is removed after step (II), the removal of the support may be performed between steps (II) and (III), between steps (III) and (IV), or between steps (IV) and (V). Furthermore, if necessary, the formation of the insulating layer and the conductor layer in steps (I) to (V) may be repeated to form a multilayer wiring board.

[0182] Step (III) is a step of drilling holes in the insulating layer, thereby forming holes such as via holes and through holes in the insulating layer. Step (III) may be performed using, for example, a drill, a laser, plasma, or the like, depending on the composition of the resin composition used to form the insulating layer. The dimensions and shape of the holes may be determined appropriately depending on the design of the printed wiring board.

[0183] Step (IV) is a step of roughening the insulating layer. Typically, smear removal is also performed in this step (IV). The roughening treatment procedure and conditions are not particularly limited, and known procedures and conditions commonly used in forming insulating layers for printed wiring boards can be adopted. For example, the insulating layer can be roughened by performing a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing liquid in this order.

[0184] Examples of swelling liquids used in the roughening treatment include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Examples of the alkaline solution include sodium hydroxide solution and potassium hydroxide solution. Examples of commercially available swelling liquids include "Swelling Dip Securigance P" and "Swelling Dip Securigance SBU" manufactured by Atotech Japan. Swelling treatment using a swelling liquid can be performed by immersing the insulating layer in the swelling liquid at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing swelling of the resin in the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in the swelling liquid at 40°C to 80°C for 5 to 15 minutes.

[0185] Examples of oxidizing agents used in the roughening treatment include alkaline permanganate solutions prepared by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. Roughening treatment using an oxidizing agent such as alkaline permanganate solution is preferably carried out by immersing the insulating layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigance P" manufactured by Atotech Japan.

[0186] The neutralizing solution used in the roughening treatment is preferably an acidic aqueous solution, and a commercially available product such as "Reduction Solution Securigant P" manufactured by Atotech Japan can be cited. Treatment with a neutralizing solution can be carried out by immersing the surface that has been roughened with an oxidizing agent in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the standpoint of workability, a preferred method is to immerse the object that has been roughened with an oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

[0187] Step (V) is a step of forming a conductor layer, and the conductor layer is formed on the insulating layer. The conductor material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor layer may be a single metal layer or an alloy layer. Examples of alloy layers include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys). Among these, from the viewpoints of versatility in forming the conductor layer, cost, ease of patterning, etc., a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy, a copper-nickel alloy, or a copper-titanium alloy is preferred, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy is more preferred, and a single metal layer of copper is even more preferred.

[0188] The conductor layer may have a single layer structure, or a multi-layer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated. When the conductor layer has a multi-layer structure, the layer in contact with the insulating layer is preferably a single metal layer of chromium, zinc, or titanium, or an alloy layer of a nickel-chromium alloy.

[0189] The thickness of the conductor layer depends on the desired design of the printed wiring board, but is generally 3 μm to 35 μm, preferably 5 μm to 30 μm.

[0190] In one embodiment, the conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer using a conventionally known technique such as a semi-additive method or a full-additive method. From the viewpoint of ease of production, the semi-additive method is preferred. An example of forming a conductor layer using a semi-additive method will be described below.

[0191] First, a plating seed layer is formed on the surface of an insulating layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer, exposing a portion of the plating seed layer corresponding to the desired wiring pattern. After a metal layer is formed on the exposed plating seed layer by electrolytic plating, the mask pattern is removed. Thereafter, unnecessary plating seed layer is removed by etching or the like, thereby forming a conductor layer having the desired wiring pattern.

[0192] In another embodiment, the conductor layer may be formed using a metal foil. When a metal foil is used to form the conductor layer, step (V) is preferably performed between steps (I) and (II). For example, after step (I), the support is removed, and a metal foil is laminated on the exposed surface of the resin composition layer. The resin composition layer and the metal foil may be laminated by a vacuum lamination method. The lamination conditions may be the same as those described for step (I). Next, step (II) is performed to form an insulating layer. Thereafter, a conductor layer having a desired wiring pattern can be formed using the metal foil on the insulating layer by a conventionally known technique such as a subtractive method or a modified semi-additive method.

[0193] The metal foil can be produced by a known method such as an electrolytic method, a rolling method, etc. Examples of commercially available metal foils include HLP foil and JXUT-III foil manufactured by JX Nippon Mining & Smelting Co., Ltd., and 3EC-III foil and TP-III foil manufactured by Mitsui Mining & Smelting Co., Ltd.

[0194] When the conductor layer is patterned, the minimum line (circuit width) / space (width between circuits) ratio of the conductor layer is not particularly limited. However, from the viewpoint of utilizing the above-mentioned advantage of the resin sheet, that is, since it is possible to detect small defects in the resin composition layer, an insulating layer free of such defects can be obtained, a small minimum line / space ratio is preferable. Specifically, the minimum line / space ratio is preferably 20 μm / 20 μm or less (i.e., a pitch of 40 μm or less), more preferably 10 μm / 10 μm or less, even more preferably 5 μm / 5 μm or less, even more preferably 1 μm / 1 μm or less, and particularly preferably 0.5 μm / 0.5 μm or less. The lower limit may be, for example, 0.1 μm / 0.1 μm or more. The pitch may or may not be uniform throughout the conductor layer. The minimum pitch of the conductor layer may be, for example, 40 μm or less, 36 μm or less, or 30 μm or less.

[0195] The circuit board such as the printed wiring board described above can be provided in a semiconductor device. Examples of the semiconductor device equipped with such a circuit board include various semiconductor devices used in electrical appliances (e.g., computers, mobile phones, digital cameras, televisions, etc.) and vehicles (e.g., motorcycles, automobiles, trains, ships, aircraft, etc.). [Example]

[0196] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples shown below. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Furthermore, the temperature and pressure conditions were room temperature (25°C) and atmospheric pressure (1 atm), unless otherwise specified.

[0197] [Type of support] The following plastic films were prepared as supports: Support 1: Polyimide film ("Xenomax" manufactured by Toyobo Co., Ltd., thickness 38 μm). Support 2: Polyethylene terephthalate film (Toray Industries, Inc.'s "Lumirror T6AM," thickness 38 μm) that had been release-treated with an alkyd resin-based release agent (Lintec Corporation's "AL-5"). Support 3: polyethylene terephthalate film (Toray Industries, Inc. "R80", thickness 38 μm). Support 4: Polyethylene terephthalate film having a release layer mainly composed of an alkyd resin-based release agent ("AL-5" manufactured by Lintec Corporation, thickness 38 μm) Support 5: Polyimide film (Toray DuPont "Kapton 200EN", thickness 50 μm)

[0198] [Reference Example 1: Observation of Support 1 Alone] The support 1 was taken out of the package in a clean room and observed according to the following procedure. Using a microscope (Keyence "VHX-7000"), optical observation of the support 1 was carried out at a magnification of 200 times with transmitted light (visible light) in the thickness direction (incident angle 0°). From the image obtained by observation, the number of defects with a maximum diameter of 10 μm or more that had a contrast or color tone different from the surrounding area (normal areas) was counted. In the Reference Examples, Examples, and Comparative Examples described here, black or brown defects were detected, and the number of these defects was counted. The observation range of the support was 1 cm per area. 2 Five areas were selected from random sections of the support and observations were conducted.

[0199] [Reference Example 2: Observation of Support 2 Alone] Observation was carried out in the same manner as in Reference Example 1, except that Support 1 was changed to Support 2, and the number of defects having a maximum diameter of 10 μm or more was counted.

[0200] [Reference Example 3: Observation of Support 3 Alone] Observation was carried out in the same manner as in Reference Example 1, except that Support 1 was changed to Support 3, and the number of defects having a maximum diameter of 10 μm or more was counted.

[0201] [Reference Example 4: Observation of Support 4 alone] Observation was carried out in the same manner as in Reference Example 1, except that Support 1 was changed to Support 4, and the number of defects having a maximum diameter of 10 μm or more was counted.

[0202] [Reference Example 5: Observation of Support 5 Alone] Observation was carried out in the same manner as in Reference Example 1, except that Support 1 was changed to Support 5, and the number of defects having a maximum diameter of 10 μm or more was counted.

[0203] [Example 1: Production and evaluation of resin sheet using support 1] (1-1. Preparation of Resin Varnish I) A solution was obtained by heating and dissolving 12 parts of a bisphenol AF epoxy resin ("YL7760" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: approximately 238 g / eq.), 12 parts of a biphenyl epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: approximately 269 g / eq.), 12 parts of a bixylenol epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: approximately 185 g / eq.), and 10 parts of a phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation, a 1:1 solution of cyclohexanone:methyl ethyl ketone (MEK) with a solids content of 30% by mass) in 15 parts of solvent naphtha and 2 parts of MEK with stirring. After cooling this solution to room temperature, 6 parts of a triazine skeleton-containing cresol novolac curing agent (DIC Corporation's "LA-3018-50P," hydroxyl group equivalent 151 g / eq., 2-methoxypropanol solution with a solid content of 50%), 16 parts of an active ester curing agent (DIC Corporation's "HPC-8000-65T," active group equivalent approximately 223 g / eq., toluene solution with a non-volatile content of 65% by mass), 16 parts of an amine curing accelerator (4-dimethylaminopyridine (DMAP), solid content 5% by mass), and 10 parts of a methyl methyl acrylate curing agent (DIC Corporation's "HPC-8000-65T," active group equivalent approximately 223 g / eq., toluene solution with a non-volatile content of 65% by mass) were added. Resin varnish I was prepared by mixing 2 parts of a 20% MEK solution and 80 parts of spherical silica (Admatechs' SO-C2, average particle size 0.50 μm) that had been surface-treated with N-phenyl-3-aminopropyltrimethoxysilane (Shin-Etsu Chemical's KBM573), dispersing the mixture uniformly in a high-speed rotary mixer, and then filtering it through a cartridge filter (Roki Techno's SHP-050, filtration efficiency (manufacturer's stated value): cutting 99.9% or more of particles 3 μm or larger).

[0204] (1-2. Formation of Resin Composition Layer) A roll of support 1 was prepared. Support 1 was removed from this roll in a clean room, and the resin varnish I obtained above was uniformly applied to the smooth surface of support 1 using a die coater, followed by drying at 80°C to 110°C (average 100°C) for 2 minutes to form a resin composition layer. The thickness of the resin composition layer was 20 μm.

[0205] (1-3. Attaching the protective film) Subsequently, a polypropylene film ("Alphan MA-411" manufactured by Oji Specialty Paper Co., Ltd., thickness 15 μm) was continuously laminated as a protective film on the surface of the resin composition layer at normal pressure, 60°C, and a linear pressure of 6 kgf / cm to obtain a resin sheet. This resin sheet had a support 1, a resin composition layer, and a protective film in this order. This resin sheet was wound up to obtain a roll (winding length 60 m). The obtained roll was slit to a width of 340 mm to obtain a roll of resin sheet 340 mm wide and 60 m long.

[0206] (1-4. Observation of resin sheet) The resin sheet was released from the roll, and the protective film was slowly peeled off to expose the resin composition layer. To prevent adhesion of foreign matter due to static electricity, the protective film was peeled off while the support 1 was held against an ionizer. By this peeling, a sample sheet was obtained as a resin sheet comprising only the support 1 and the resin composition layer.

[0207] Defect detection of the sample sheet was carried out in the same manner as in Reference Example 1. Specifically, using a microscope (Keyence Corporation "VHX-7000"), optical observation of the sample sheet was carried out using transmitted light (visible light) in the thickness direction (incident angle 0°) at a magnification of 200x. This optical observation was carried out by placing the sample sheet so that the resin composition layer faced the lens side, so that the light emitted from the microscope's light source would pass through the support 1 and the resin composition layer in this order and enter the microscope lens. From the image obtained by observation, the number of defects with a maximum diameter of 10 μm or more that had a contrast or color tone different from the surrounding normal parts was counted. The observation area of ​​the sample sheet was 1 cm per area. 2Five areas were selected from any department on the sample sheet and observations were conducted.

[0208] Comparative Example 1: Production and Evaluation of Resin Sheet Using Support 2 A resin sheet was manufactured and observed in the same manner as in Example 1, except that support 1 was changed to support 2 and varnish was applied to the release layer side of support 2, and the number of defects with a maximum diameter of 10 μm or more was counted.

[0209] Comparative Example 2: Production and Evaluation of Resin Sheet Using Support 3 A resin sheet was produced and observed in the same manner as in Example 1, except that the support 3 was used in Example 1, and the number of defects having a maximum diameter of 10 μm or more was counted.

[0210] Comparative Example 3: Production and Evaluation of Resin Sheet Using Support 4 A resin sheet was manufactured and observed in the same manner as in Example 1, except that the support 4 in Example 1 was changed and varnish was applied to the release layer side of the support 4, and the number of defects with a maximum diameter of 10 μm or more was counted.

[0211] Comparative Example 4: Production and Evaluation of Resin Sheet Using Support 5 A resin sheet was produced and observed in the same manner as in Example 1, except that the support 5 was used in Example 1, and the number of defects having a maximum diameter of 10 μm or more was counted.

[0212] Reference Example 6: Production and evaluation of control sample A using a glass support The support used in Example 1 was changed to a glass support, and a control sample A was produced as a laminate including a glass support and a resin composition layer by the following method. A flat glass plate was prepared as the glass support. Adherents on the surface of the glass support were removed using a nitrogen blower. Resin varnish I obtained in Example 1 was uniformly applied to one side of the glass support using a bar coater, and dried at 80°C to 110°C (average 100°C) for 2 minutes to form a resin composition layer. The thickness of the resin composition layer was 20 μm. Through the above operations, a control sample A was obtained, which included a glass support and a resin composition layer formed on this glass support.

[0213] Defect detection was carried out on control sample A using the same method as in Reference Example 1. Specifically, optical observation of control sample A was carried out using a microscope (Keyence "VHX-7000") at a magnification of 200x with transmitted light (visible light) in the thickness direction (incident angle 0°). From the image obtained by observation, the number of defects with a maximum diameter of 10 μm or more that had a contrast or color tone different from the surrounding normal areas was counted. The observation range of control sample A was 1 cm per area. 2 Five areas were selected from random sections of control sample A and observations were conducted.

[0214] The glass support does not have any defects. Therefore, the number of defects in the control sample A represents the number of defects caused by defects contained in the resin composition layer.

[0215] [Example 2: Production and evaluation of resin sheet using support 1 and black filler-containing resin composition] A black filler (KUAMET 6B2 manufactured by Epson Atmix, an Fe-based amorphous magnetic material, average particle size 25 μm) was added to the resin varnish I obtained in Example 1 and mixed with a mixer (Thinky Corporation's Awatori Rentaro) to prepare a resin varnish II containing the black filler. The amount of black filler used was such that the concentration of the black filler in the resin varnish II was 50 ppm.

[0216] A resin sheet was produced and observed in the same manner as steps (1-2) to (1-4) of Example 1, except that resin varnish I was changed to resin varnish II containing black filler obtained above, and the number of defects with a maximum diameter of 10 μm or more was counted.

[0217] Comparative Example 5: Production and evaluation of resin sheet using support 2 and black filler-containing resin composition An adhesive sheet was produced and observed in the same manner as in Example 2, except that Support 1 was changed to Support 2, and the number of defects with a maximum diameter of 10 μm or more was counted.

[0218] Comparative Example 6: Production and evaluation of a resin sheet using a support 3 and a resin composition containing a black filler An adhesive sheet was produced and observed in the same manner as in Example 2, except that support 1 was changed to support 3, and the number of defects with a maximum diameter of 10 μm or more was counted.

[0219] Comparative Example 7: Production and evaluation of a resin sheet using a support 4 and a resin composition containing a black filler An adhesive sheet was produced and observed in the same manner as in Example 2, except that support 1 was changed to support 4, and the number of defects with a maximum diameter of 10 μm or more was counted.

[0220] Comparative Example 8: Production and evaluation of a resin sheet using a support 5 and a resin composition containing a black filler An adhesive sheet was produced and observed in the same manner as in Example 2, except that Support 1 was changed to Support 5, and the number of defects with a maximum diameter of 10 μm or more was counted.

[0221] Reference Example 7: Production and evaluation of control sample B using a glass support The support used in Example 2 was changed to a glass support, and a control sample B was produced as a laminate including a glass support and a resin composition layer by the following method. A flat glass plate was prepared as the glass support. A nitrogen blower was used to remove any deposits on the surface of the glass support. The resin varnish II containing the black filler obtained in Example 2 was uniformly applied to one side of the glass support using a bar coater, and dried at 80°C to 110°C (average 100°C) for 2 minutes to form a resin composition layer containing the black filler. The thickness of the resin composition layer containing the black filler was 20 μm. Through the above operations, a control sample B was obtained, which included a glass support and a resin composition layer containing the black filler formed on the glass support.

[0222] Defect detection was carried out on control sample B using the same method as in Reference Example 1. Specifically, optical observation of control sample B was carried out using a microscope (Keyence Corporation "VHX-7000") at a magnification of 200 times with transmitted light (visible light) in the thickness direction (incident angle 0°). From the image obtained by observation, the number of defects with a maximum diameter of 10 μm or more that had a contrast or color tone different from the surrounding normal parts was counted. The measurement range of control sample B was 1 cm per area. 2 Five areas were selected from random sections of control sample B and observations were conducted.

[0223] The glass support does not have any defects. Therefore, the number of defects in the control sample B represents the number of defects caused by defects contained in the resin composition layer containing the black filler.

[0224] [result] The results of the above-mentioned Examples, Comparative Examples, and Reference Examples are shown in the table below. In the table below, the values ​​in the "Detection Error" column represent the difference between the average number of defects in the Examples and Comparative Examples and the average number of defects in the corresponding Control. Therefore, the detection error values ​​for Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 represent the difference between the average number of defects in Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 and the average number of defects in Reference Example 6. Furthermore, the detection error values ​​for Example 2, Comparative Example 5, Comparative Example 6, Comparative Example 7, and Comparative Example 8 represent the difference between the average number of defects in Example 2, Comparative Example 5, Comparative Example 6, Comparative Example 7, and Comparative Example 8 and the average number of defects in Reference Example 7. Therefore, the smaller the absolute value of the detection error value, the lower the frequency of false detection, and therefore, the higher the detection accuracy of small defects in the resin composition layer.

[0225] [Table 1] [Explanation of symbols]

[0226] 1 Manufacturing equipment 10 Support 20 Resin composition layer 30 Inspected sheet (resin sheet) 40 Product Sheet (Resin Sheet) 50 Resin composition 60 rolls 100 layer forming device 110 Coating equipment 120 Drying equipment 200 Detection Device 210 Light source section 220 Photography Department 230 Output section 300 Emission Device

Claims

1. A support having a release layer and a resin composition layer formed on the release layer of the support, the resin composition layer contains a resin composition, the dielectric loss tangent of the cured product of the resin composition is 0.05 or less; The number of defects having a maximum diameter of 10 μm or more on the support is 5 / cm ２ Below is a resin sheet.

2. The resin sheet according to claim 1 , wherein the defect is a point that can be detected by optical observation.

3. The resin sheet according to claim 1 or 2, wherein the defect is present inside the support.

4. The resin sheet according to any one of claims 1 to 3, wherein the support is a plastic film.

5. The resin sheet according to any one of claims 1 to 4, which is for forming an insulating layer.

6. A method for producing a resin sheet comprising a support having a release layer and a resin composition layer formed on the support; forming the resin composition layer on the release layer of the support; and performing optical observation of the support and the resin composition layer simultaneously to detect defects; the resin composition layer contains a resin composition, the dielectric loss tangent of the cured product of the resin composition is 0.05 or less; The number of defects having a maximum diameter of 10 μm or more on the support is 5 / cm ２ The following is a method for manufacturing a resin sheet.

7. A method for detecting defects in a resin composition layer of a resin sheet comprising a support having a release layer and a resin composition layer formed on the release layer of the support, a step of simultaneously optically observing the support and the resin composition layer to detect defects, the resin composition layer contains a resin composition, the dielectric loss tangent of the cured product of the resin composition is 0.05 or less; The number of defects having a maximum diameter of 10 μm or more on the support is 5 / cm ２ The defect detection method is as follows.

8. 8. The defect detection method according to claim 7, wherein the defect having a maximum diameter of 10 μm or more in the support is located inside the support.

9. 9. The defect detection method according to claim 7, wherein the support is a plastic film.

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