Method for manufacturing wiring board, wiring board, and curable resin composition

Abstract

Provided is a method for manufacturing a wiring board comprising a first step for forming, on a glass base material, a first insulating resin layer containing a maleimide resin such that the glass base material and the first insulating resin layer are in direct contact with each other.

Description

Method for manufacturing wiring board, wiring board, and curable resin composition

[0001] The present disclosure relates to a method for producing a wiring board, a wiring board, and a curable resin composition.

[0002] In recent years, with the increasing sophistication of semiconductor applications, the logic semiconductors, AI semiconductors, advanced SoCs (System on Chip) and the like used therein have also been seeing progress in the high integration of semiconductor packages through the application of techniques such as SiPs (System in Package), chiplets, heterogeneous integration, etc. Specifically, as the number of processor cores increases for the purpose of high-speed signal transmission and improved arithmetic processing, studies are being conducted to improve performance through structural innovations such as finer wiring, higher density, larger substrates, and more multi-layered structures using semiconductor chips, package substrates, redistribution layers (RDLs), and interposers. Furthermore, cutting-edge semiconductor packages tend to integrate a wide variety of functions, such as analog circuits and radio frequency (RF) circuits, and in addition, with the convergence of photonics and electronics, the addition of optical wiring, optical engines, and I / O interfaces (optical-electrical conversion units) is expected, requiring further improvements in the electrical properties of the insulating resin layers and adhesive layers used therein. Against this background, development of wiring substrates with low dielectric properties is underway (Patent Document 1).

[0003] It has also been considered to use a glass substrate as the substrate of a wiring board. Patent Document 2 discloses that a packaging glass substrate for semiconductors is produced by forming a primer layer on a glass substrate.

[0004] Japanese Patent Application Laid-Open No. 2024-015869 Special Publication No. 2022-517062

[0005] Because glass has a minimal surface irregularity, it tends to be more difficult for a glass substrate to adhere to an insulating resin layer than substrates made of other materials, such as organic substrates. Therefore, an adhesive layer is typically used when laminating an insulating substrate layer on a glass substrate. However, conventional adhesive layers use polar components to ensure adhesion to glass, and such wiring boards tend to have reduced dielectric properties. Therefore, it has been difficult to achieve low dielectric properties in wiring boards whose substrates are made of glass.

[0006] The present disclosure has been made in consideration of such problems, and aims to provide a wiring board manufacturing method, a wiring board, and a curable resin composition that can manufacture a wiring board having an insulating resin layer that has excellent adhesion to a glass substrate and good dielectric properties.

[0007] In order to solve the above problems, the present disclosure provides the following method for producing a wiring board, a wiring board, and a curable resin composition.

[0008] [1] A method for manufacturing a wiring board, comprising: a first step of forming a first insulating resin layer containing a maleimide resin on a glass substrate such that the glass substrate and the first insulating resin layer are in direct contact with each other. [2] The manufacturing method according to [1], further comprising: a second step of forming a circuit in the first insulating resin layer after the first step; and a third step of curing at least the first insulating resin layer after the second step. [3] The manufacturing method according to [2], further comprising: a step of forming one or more other insulating resin layers on the surface of the first insulating resin layer opposite the glass substrate after the second step and before the third step. [4] A wiring board comprising a glass substrate and a first insulating resin layer in direct contact with the glass substrate, the first insulating resin layer containing a maleimide resin. [5] The wiring board according to [4], in which a circuit is formed in the first insulating resin layer. [6] The wiring board according to [4] or [5], further comprising one or more other insulating resin layers on the surface of the first insulating resin layer opposite the glass substrate. [7] A curable resin composition for forming a first insulating resin layer in a wiring board including a glass substrate and a first insulating resin layer in direct contact with the glass substrate, the curable resin composition containing a maleimide resin.

[0009] According to the present disclosure, it is possible to provide a wiring board manufacturing method, a wiring board, and a curable resin composition that can manufacture a wiring board having an insulating resin layer that has excellent adhesion between the insulating resin layer and the glass substrate and good dielectric properties.

[0010] Fig. 1 is a flow diagram for explaining one embodiment of a wiring board manufacturing method according to the present embodiment; Fig. 2 is a schematic cross-sectional view showing an example of a wiring board manufactured by the wiring board manufacturing method according to the present embodiment; Fig. 3 is a schematic cross-sectional view showing an example of a wiring board manufactured by the wiring board manufacturing method according to the present embodiment; Fig. 4 is a schematic cross-sectional view showing an example of a wiring board manufactured by the wiring board manufacturing method according to the present embodiment.

[0011] Hereinafter, several embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following embodiments.

[0012] In this specification, numerical ranges indicated using "to" indicate ranges that include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range may be replaced with the upper or lower limit of another numerical range. Furthermore, in numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with a value shown in the Examples. When referring to the amount of each component in a composition in this specification, if multiple substances corresponding to each component are present in the composition, unless otherwise specified, this refers to the total amount of those multiple substances present in the composition. "A or B" may contain either A or B, or both. "Solid content" refers to the non-volatile content of a resin composition excluding volatile substances (water, solvent, etc.). In other words, "solid content" refers to components other than the solvent that remain without volatilizing during drying of the resin composition, as described below, and also includes components that are liquid, syrup-like, or waxy at room temperature (25°C). In this specification, for example, "(meth)acrylic" means "acrylic" and its corresponding "methacrylic", and the same applies to other similar terms.

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments.

[0014] [Method for Manufacturing a Wiring Board] The method for manufacturing a wiring board according to this embodiment includes a first step of forming a first insulating resin layer containing a maleimide resin on a glass substrate so that the glass substrate and the first insulating resin layer are in direct contact with each other. Because the insulating resin layer containing a maleimide resin has excellent adhesion to glass, it can be formed in direct contact with the glass substrate, eliminating the need for bonding to the glass substrate via an adhesive layer as in the past. Furthermore, the insulating resin layer containing a maleimide resin also has excellent dielectric properties. Therefore, according to the method for manufacturing a wiring board according to this embodiment, a wiring board can be manufactured that has excellent adhesion between the insulating resin layer and the glass substrate and an insulating resin layer with good dielectric properties. Furthermore, according to the method for manufacturing a wiring board according to this embodiment, the step of forming an adhesive layer between the glass substrate and the insulating resin layer can be omitted, thereby improving manufacturing efficiency. Furthermore, because the insulating resin layer containing a maleimide resin has little warping, wiring boards including such insulating resin layers tend to have excellent mechanical strength.

[0015] The first insulating resin layer may be formed on a portion of the main surface of the glass substrate, or may be formed on the entire surface. A circuit such as a seed layer or an electrically conductive layer may be formed in a portion of the glass substrate by copper plating, sputtering, or the like. When the first insulating resin layer is formed on such a glass substrate, the first insulating resin layer is formed so that a portion of the main surface of the glass substrate and the first insulating resin layer are in direct contact with each other. An insulating resin layer containing a maleimide resin also has excellent adhesion to copper.

[0016] 1 is a flow diagram illustrating one embodiment of a method for manufacturing a wiring board according to the present disclosure. As shown in FIG. 1, one embodiment of the method for manufacturing a wiring board according to the present disclosure includes a step (first step) of forming a first insulating resin layer on a glass substrate so that the glass substrate and the first insulating resin layer are in direct contact with each other, a step (second step) of forming a circuit on the first insulating resin layer, a step (build-up step) of forming one or more insulating resin layers other than the first insulating resin layer, and a step (third step) of collectively curing the insulating resin layers including the first insulating resin layer (the first insulating resin layer and one or more other insulating resin layers). Note that, although the embodiment shown in FIG. 1 includes the second step, the build-up step, and the third step, these steps are optional and may or may not be included in the embodiment of the method for manufacturing a wiring board according to the present disclosure.

[0017] Each insulating resin layer formed in the wiring board manufacturing method according to the present disclosure may be in the form of a resin-coated copper foil (RCC). When the insulating resin layer is formed in the form of an RCC, the thickness of the copper foil in the RCC is not particularly limited and may be 10 μm or more and 100 μm or less. The thickness of the resin layer in the RCC is also not particularly limited and may be 10 μm or more and 50 μm or less.

[0018] (First Step) In the first step, a first insulating resin layer containing a maleimide resin is formed on a glass substrate so that the glass substrate and the first insulating resin layer are in direct contact with each other. That is, in the first step, the first insulating resin layer is formed directly on the glass substrate.

[0019] A glass substrate is a substrate made of glass. Its dimensional stability is high due to its low thermal expansion and contraction. Glass expands and contracts little due to heat. Furthermore, compared to organic substrates, its thermal expansion coefficient is closer to that of silicon (Si), the substrate for silicon dies and silicon interposers, and it also has high flatness in glass panels. Therefore, glass substrates can be made larger in area, are suitable for finer wiring and for densely forming through-hole electrodes in the glass core, and also have excellent high-temperature operation and high-frequency characteristics. In addition, they are compatible with large-panel manufacturing processes, allowing for highly efficient mass production. Therefore, glass substrates are suitable for finer wiring, and are easy to form multilayer wiring on, and also have excellent high-frequency characteristics.

[0020] The glass for forming the glass substrate is not particularly limited, and examples thereof include soda glass, quartz glass, borosilicate glass, and alkali-free glass.

[0021] The thickness of the glass substrate may be 25 μm or more and 1000 μm or less.

[0022] A through electrode may be formed in the glass substrate. The through electrode may be formed, for example, by at least partially filling a hole with a conductor, or by coating the surface of the hole with a conductor. The through electrode may be formed, for example, from copper or silver. The size of the through electrode is not particularly limited, and may be, for example, from 5 μm to 200 μm in diameter.

[0023] The glass substrate may have holes. A coating layer that partially covers the surface of the glass substrate (including the surface of the holes, if any) may be formed on the glass substrate. The coating layer according to this embodiment includes a structure having a shape formed on the entire surface of the substrate when observed in a plan view, as well as a structure having a shape formed on a part of the substrate.

[0024] The glass substrate may have an electronic component built in. For example, examples of the electronic component built in the glass substrate include a semiconductor chip, a capacitor, an inductor, a resistor, a diode, and a transistor. One method for building an electronic component in a glass substrate is to form a cavity in the glass substrate and place the electronic component in the cavity. However, a glass substrate with an electronic component built in may also be produced by a method other than this.

[0025] The coating layer that covers the surface of the glass substrate (including the surfaces of the holes, if any) may be a conductor layer. The conductor layer may be a circuit. A circuit may be formed on the glass substrate. A glass substrate on which a circuit has been formed in advance may be used, or a glass substrate on which no circuit has been formed may be prepared and a circuit may be formed on it. The method for forming a circuit on the glass substrate is not particularly limited, and a circuit may be formed directly on the glass substrate by plating or sputtering.

[0026] The first insulating resin layer is formed from a curable resin composition containing a maleimide resin. The method for forming the first insulating resin layer is not particularly limited, but from the viewpoint of excellent production efficiency, the first insulating resin layer may be formed by directly laminating the curable resin composition containing a maleimide resin as a resin film onto a glass substrate.

[0027] The first insulating resin layer may be formed by applying a curable resin composition to a substrate and then semi-curing the composition. Examples of methods for applying the curable resin composition include methods using a spin coater, a slit coater, or the like. Examples of methods for semi-curing the curable resin composition include drying at 60°C to 150°C for 1 to 120 minutes, followed by heating at 150°C to 260°C for 0.5 to 60 minutes or exposing the composition to an exposure dose of 100 to 1000 mJ / cm. ２ In one example, the curable resin composition is semi-cured by irradiating the curable resin composition with ultraviolet light.

[0028] The maleimide resin (hereinafter also referred to as "component (A)") can be obtained, for example, by reacting a tetracarboxylic dianhydride (a1) (hereinafter also referred to as "component (a1)"), an amine (a2) (hereinafter also referred to as "component (a2)"), and maleic anhydride (a3) ​​(hereinafter also referred to as "component (a3)"). Here, the component (a2) may contain dimer diamine. The component (A) can be used alone or in combination of two or more types.

[0029] The tetracarboxylic dianhydride of component (a1) can be any known polyimide raw material. Examples of component (a1) include pyromellitic anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-c]furan-1,3-dione, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone ... ,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene- 2,3,5,6-tetracarboxylic dianhydride, bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid) 1,4-phenylene, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, 4,4'-(ethyne-1,2-diyl)diphthalic anhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, dicyclohexyl-3,4,3',4'-tetracarbo diphthalic anhydride, 3,4'-oxydiphthalic anhydride, 3,4'-biphthalic anhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride, 5,5'-bis-2-norbornene-5,5',6,6'-tetracarboxylic-5,5',6,6'-dianhydride, and 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride.Among these, from the viewpoint of availability, pyromellitic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, and 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride are preferred, and from the viewpoint of heat resistance, pyromellitic anhydride is particularly preferred. The component (a1) can be used alone or in combination of two or more.

[0030] The (a2) component may contain dimer diamine. As described in, for example, JP-A-9-12712, dimer diamine is a compound derived from a dimer acid, which is a dimer of an unsaturated fatty acid such as oleic acid. By using dimer diamine as the (a2) component, the dielectric properties of the cured product can be reduced. In this embodiment, any known dimer diamine can be used without particular limitation. The dimer diamine preferably includes, for example, at least one of a compound represented by the following general formula (1) and a compound represented by the following general formula (2):

[0031]

[0032] In formulas (1) and (2), m, n, p, and q each represent an integer of 1 or greater selected so that m+n=6 to 17 and p+q=8 to 19, and the bond shown by a dashed line represents a carbon-carbon single bond or a carbon-carbon double bond. However, when the bond shown by a dashed line is a carbon-carbon double bond, formulas (1) and (2) have a structure in which the number of hydrogen atoms bonded to each carbon atom constituting the carbon-carbon double bond is reduced by one from the number shown in formulas (1) and (2).

[0033] The dimer diamine may be one represented by the above general formula (2), particularly a compound represented by the following formula (3), from the viewpoints of solubility in organic solvents, heat resistance, heat-resistant adhesion, low viscosity, etc.

[0034]

[0035] Commercially available dimer diamine products include, for example, PRIAMINE 1075 and PRIAMINE 1074 (both manufactured by Cargill Japan LLC).

[0036] The component (a2) may contain an amine other than dimer diamine (hereinafter also referred to as "second amine"). The second amine is an amine that does not fall under the category of the above-mentioned dimer diamine. The second amine may be a diamine or triamine, or may be a diamine. By using an alicyclic diamine as the second amine, the dielectric constant can be further reduced. By using an aromatic diamine as the second amine, the elastic modulus and Tg of the cured product can be increased, and the CTE can be reduced.

[0037] When the second amine is a diamine, examples of the diamine include 1,3-diaminopropane, norbornanediamine, 4,4-methylenedianiline, 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis[3-fluoro-4-aminophenyl]fluorene, 9,9-bis[4-(4-aminophenoxy)phenyl]fluorene, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(aminomethyl)norbornane, 4,4'-(hexafluoroisopropylidene)dianiline, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0 ２，６]decane, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, isophoronediamine, 4,4'-methylenebis(cyclohexylamine), 4,4'-methylenebis(2-methylcyclohexylamine), 1,1-bis(4-aminophenyl)cyclohexane, 2,7-diaminofluorene, 4,4'-ethylenedianiline, 4,4'-methylenebis(2,6-diethylaniline), 4,4'-methylenebis(2-ethyl-6-methylaniline), 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]methane, 4,4'-bis(4-aminophenoxy)biphenyl , bis[4-(4-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ketone, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 2,2'-dimethylbiphenyl-4,4'-diamine, (4,4'-diamino)diphenyl ether, (3,3'-diamino)diphenyl ether, paraphenylenediamine, orthophenylenediamine, metaphenylenediamine, 2,2'-dimethylbiphenyl-4,4'-diamine, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, etc. These can be used alone or in combination of two or more.

[0038] When the second amine is a triamine, examples of the triamine include tris(aminomethyl)amine, tris(2-aminoethyl)amine, tris(2-aminopropyl)amine, 2-(aminomethyl)-2-methyl-1,3-propanediamine, trimer triamine, 3,4,4'-triaminodiphenyl ether, 1,2,4-triaminobenzene, 1,3,5-triaminobenzene, 1,2,3-triaminobenzene, 1,3,5-triazine-2,4,6-triamine, 2,4,6-triaminopyrimidine, 1,3,5-tris(4-aminophenyl)benzene, and 1,3,5-tris(4-aminophenoxy)benzene. Among these, from the viewpoint of photocurability, aliphatic amines and alicyclic amines are preferred, and norbornanediamine, isophoronediamine, and tris(2-aminoethyl)amine are more preferred. These may be used alone or in combination of two or more.

[0039] The second amine may include one or both of the above-mentioned diamines and triamines, or may include an amine other than the diamines and triamines.

[0040] In component (a2), the molar ratio of the second amine to the total amount of amines (moles of second amine / (moles of dimer diamine+moles of second amine)) may be 0.70 or less, 0.50 or less, or 0.30 or less. When this ratio is 0.70 or less, the dielectric properties of the cured product can be further reduced.

[0041] When the second amine contains a diamine, the molar ratio of the diamine in the second amine to the total amount of diamine in component (a2) (number of moles of diamine in the second amine / (number of moles of dimer diamine + number of moles of diamine in the second amine)) may be 0.70 or less, 0.50 or less, or 0.30 or less. When this ratio is 0.70 or less, the dielectric properties of the cured product can be further reduced.

[0042] Component (A) can be produced by various known methods. For example, components (a1) and (a2) are first subjected to a polyaddition reaction at a temperature of about 60 to 120°C, preferably 70 to 90°C, for typically about 0.1 to 2 hours, preferably 0.1 to 1.0 hour. The resulting polyaddition product is then subjected to an imidization reaction, i.e., a dehydration ring-closing reaction, at a temperature of about 80 to 250°C, preferably 100 to 200°C, for about 0.5 to 30 hours, preferably 0.5 to 10 hours. The product of the dehydration ring-closing reaction is then subjected to a maleimidization reaction, i.e., a dehydration ring-closing reaction, with component (a3) ​​at a temperature of about 60 to 250°C, preferably 80 to 200°C, for about 0.5 to 30 hours, preferably 0.5 to 10 hours, to obtain the desired component (A).

[0043] In the imidization reaction or maleimidization reaction, various known reaction catalysts, dehydrating agents, and organic solvents can be used.

[0044] Examples of the reaction catalyst include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, heterocyclic tertiary amines such as pyridine, picoline, isoquinoline, and organic acids such as methanesulfonic acid, paratoluenesulfonic acid monohydrate, etc. Examples of the dehydrating agent include aliphatic acid anhydrides such as acetic anhydride, and aromatic acid anhydrides such as benzoic anhydride.

[0045] Examples of organic solvents used in the reaction include aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, and pseudocumene; alcoholic solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol; ketone solvents such as acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclopentanone, cyclohexanone, isophorone, and acetophenone; cellosolves such as methyl cellosolve and ethyl cellosolve, ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, butyl formate, and γ-butyrolactone; and ethylene glycol mono-n-butyl ether. Examples of suitable organic solvents include glycol ether solvents such as ethylene glycol mono-iso-butyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-iso-butyl ether, triethylene glycol monoethyl ether, triethylene glycol mono-n-butyl ether, and tetraethylene glycol mono-n-butyl ether; and nitrogen-containing compounds such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, and 3-butoxy-N,N-dimethylpropanamide. These organic solvents can be used alone or in combination of two or more. From the viewpoint of solubility, it is preferable to use a combination of toluene, xylene, mesitylene, or pseudocumene with methanol or ethanol.

[0046] Component (A) can be purified by various known methods to increase its purity. For example, first, component (A) dissolved in an organic solvent and pure water are placed in a separatory funnel. The separatory funnel is then shaken and allowed to stand. Subsequently, the aqueous layer and the organic layer are separated, and only the organic layer is recovered, thereby purifying component (A).

[0047] An example of the structure of component (A) produced by the above method is shown in general formula (4) below.

[0048] In general formula (4), each X independently represents a tetravalent organic group, each Y independently represents a divalent organic group, and a represents an integer of 1 or greater. However, at least one of the multiple Ys represents the divalent organic group derived from the dimer diamine. Furthermore, X and Y may be an aliphatic group, an organic group having an alicyclic structure, or an aromatic ring, and may contain a heteroatom.

[0049] The molecular weight of component (A) can be controlled by the number of moles of component (a1) and component (a2), and the smaller the number of moles of component (a1) is relative to the number of moles of component (a2), the smaller the molecular weight can be. For the purpose of easily achieving the effects of the present disclosure, the number of moles of component (a1) per mole of component (a2), i.e., [number of moles of component (a1)] / [number of moles of component (a2)], is usually in the range of about 0.30 to 0.95, preferably 0.50 to 0.85.

[0050] From the viewpoint of solubility in solvents and heat resistance, the molecular weight of component (A) is preferably a weight average molecular weight (Mw) of 3,000 to 40,000, more preferably 4,000 to 30,000, and even more preferably 5,000 to 28,000, or 7,000 to 27,000. A weight average molecular weight of 40,000 or less tends to provide good solubility in organic solvents, while a weight average molecular weight of 3,000 or more tends to provide a sufficient effect of improving heat resistance. Mw can be measured by gel permeation chromatography (GPC) and converted using a calibration curve of standard polystyrene.

[0051] As the maleimide resin, from the viewpoint of superior adhesion and dielectric properties, the maleimide resin represented by the above general formula (4) is preferred, and in particular, the maleimide resin obtained by reacting dimer diamine as the component (a2) is preferred.

[0052] As the component (A), commercially available compounds can also be used. Specific examples that can be used preferably include SFR-2300MR-T (synthesized from an amine including dimer diamine, a tetracarboxylic dianhydride, and maleic anhydride) manufactured by Resonac Co., Ltd., and BMI-3000 Commercial Grade (synthesized from dimer diamine, pyromellitic dianhydride, and maleic anhydride), BMI-1500, BMI-1700, and BMI-5000 manufactured by DESIGNER MOLECULES Inc.

[0053] From the viewpoint of achieving better adhesion and dielectric properties, the content of component (A) may be 60 mass % or more, 80 mass % or more, 90 mass % or more, 95 mass % or more, or 100 mass % based on the total amount of resin components in the first insulating resin layer.

[0054] The first insulating resin layer may contain other resins or crosslinking agents in addition to component (A). Examples of other resins and crosslinking agents include epoxy resins, phenolic resins, (meth)acrylic resins, (meth)acrylate monomers, vinyl monomers, and benzoxazine. The total content of the other resins and crosslinking agents may be 40% by mass or less, or may be 5% by mass or more and 20% by mass or less, based on the total amount of component (A), other resins, and crosslinking agents in the first insulating resin layer.

[0055] The resin composition forming the first insulating resin layer may contain components other than the resin component, such as a polymerization initiator, a curing accelerator, an inorganic filler, a release agent, a flame retardant, an ion trapping agent, an antioxidant, an adhesion promoter, a stress reducing agent, a colorant, and a coupling agent.

[0056] Examples of the polymerization initiator include thermal radical polymerization initiators, organic peroxide compounds, azo compounds, etc. The polymerization initiators may be used alone or in combination of two or more.

[0057] Examples of the curing accelerator include phosphine compounds, compounds having a phosphonium salt, imidazole compounds, etc. The curing accelerators may be used alone or in combination of two or more.

[0058] Inorganic fillers are added to reduce the thermal expansion coefficient of the curable resin composition and improve its moisture resistance reliability. Examples of such inorganic fillers include silicas such as fused silica, crystalline silica, and cristobalite, alumina, silicon nitride, aluminum nitride, boron nitride, titanium oxide, glass fiber, and magnesium oxide. The average particle size and shape of these inorganic fillers can be selected depending on the application. Among these, spherical alumina, spherical fused silica, and glass fiber are preferred.

[0059] Mold release agents are added to improve releasability from a mold. Examples of mold release agents include carnauba wax, rice wax, candelilla wax, polyethylene, polyethylene oxide, polypropylene, montanic acid, montan wax which is an ester compound of montanic acid with saturated alcohol, 2-(2-hydroxyethylamino)ethanol, ethylene glycol, glycerin, etc., stearic acid, stearic acid ester, and stearic acid amide.

[0060] The flame retardant is added to impart flame retardancy. Known flame retardants can be used without any particular limitation. Examples of the flame retardant include phosphazene compounds, silicone compounds, zinc molybdate-supported talc, zinc molybdate-supported zinc oxide, aluminum hydroxide, magnesium hydroxide, and molybdenum oxide.

[0061] The ion trapping agent is added to the liquid resin composition to trap ionic impurities and prevent thermal and moisture-absorbing deterioration. Any known ion trapping agent can be used, and there is no particular limitation. Examples of the ion trapping agent include hydrotalcites, bismuth hydroxide compounds, and rare earth oxides.

[0062] From the viewpoint of achieving better adhesion and dielectric properties, the content of component (A) is preferably more than 50 parts by mass, and may be 60 parts by mass or more, 80 parts by mass or more, 90 parts by mass or more, 95 parts by mass or more, or 100 parts by mass, when the total amount of the first insulating resin layer is 100 parts by mass, or may be 55 to 99 parts by mass, 60 to 96 parts by mass, 70 to 92 parts by mass, or 80 to 90 parts by mass.

[0063] The thickness of the first insulating resin layer may be 1 μm or more and 200 μm or less.

[0064] An insulating resin layer may be further formed on a side surface of the glass substrate. When an insulating resin layer is further formed on a side surface of the glass substrate, the insulating resin layer may be formed on a part of the side surface of the glass substrate, or the insulating resin layer may be formed on the entire side surface of the glass substrate. The insulating resin layer formed on the side surface of the glass substrate may be formed integrally with the first insulating resin layer. An insulating resin layer may be further formed on the surface of the glass substrate opposite to the first insulating resin layer. The insulating resin layer formed on the surface of the glass substrate opposite to the first insulating resin layer may be formed integrally with the insulating resin layer formed on the side surface of the glass substrate.

[0065] When the insulating resin layer formed on the side surface of the glass substrate is formed integrally with the first insulating resin layer, and when the insulating resin layer formed on the surface of the glass substrate opposite the first insulating resin layer is formed integrally with the insulating resin layer formed on the side surface of the glass substrate, the glass substrate is covered with an insulating resin layer containing maleimide.

[0066] (Second step) The method for manufacturing a wiring board according to the present disclosure may further include a second step of forming a circuit in the first insulating resin layer after the first step, and a third step of curing at least the first insulating resin layer after the second step.

[0067] Since an insulating resin layer containing a maleimide resin is easier to process circuits in even before the resin layer is fully cured (e.g., in a B-stage state) than an insulating resin layer not containing a maleimide resin, there is no need to perform a curing step each time an insulating resin layer is laminated, as in the past. Therefore, according to the method for manufacturing a wiring board of this embodiment, one or more insulating resin layers (at least a first insulating resin layer) can be laminated in a state before they are fully cured, and then the layers can be cured (fully cured) all at once, thereby reducing the number of times the curing step is performed compared to conventional methods for manufacturing wiring boards and improving manufacturing efficiency.

[0068] The method for forming the circuit is not particularly limited, and examples thereof include a subtractive method, a semi-additive method (SAP), a modified semi-additive method (MSAP), etc. From the viewpoint of being able to form a more highly miniaturized circuit, it is preferable to form the circuit by SAP or MSAP, and from the viewpoint of further improving production efficiency, it is preferable to form the circuit by MSAP.

[0069] (Build-up Process) The method for manufacturing a wiring board according to this embodiment may further include, after the second process and before the third process, a process (build-up process) of forming one or more other insulating resin layers (hereinafter also referred to as "N insulating resin layers" or "build-up layers") on the surface of the first insulating resin layer opposite the glass substrate. N represents an integer of 1 or greater. The N insulating resin layers formed in the build-up process are also referred to as the second insulating resin layer, ..., the Nth insulating resin layer, in stacking order. The build-up layer may be formed on the surface of the first insulating resin layer opposite the substrate, or on the surface of the substrate opposite the first insulating resin layer. Alternatively, a build-up layer may be formed on both the surface of the first insulating resin layer opposite the substrate and the surface of the substrate opposite the first insulating resin layer.

[0070] When N is 1, the insulating resin layer formed on the surface of the first insulating resin layer opposite to the glass substrate (hereinafter also referred to as the "second insulating resin layer") may or may not contain a maleimide resin. Furthermore, the second insulating resin layer may contain a resin other than the maleimide resin.

[0071] When N is 2, the N insulating resin layers are referred to as the second insulating resin layer and the third insulating resin layer in the stacking order. In this case, if the second insulating resin layer contains maleimide resin, circuits can be formed in the first insulating resin layer and the second insulating resin layer before performing the third step, and the first to third insulating resin layers can be cured together after forming the third insulating resin layer. The third insulating resin layer may or may not contain maleimide resin. Furthermore, the second insulating resin layer and the third insulating resin layer may contain resins other than maleimide resin.

[0072] When N is 3 or more, the N insulating resin layers are referred to in stacking order as the second insulating resin layer, ..., the Nth insulating resin layer, and the (N+1)th insulating resin layer. In this case, by containing maleimide resin in the second to Nth insulating resin layers, circuits can be formed in each of the first to Nth insulating resin layers before performing the third step, and the first to (N+1)th insulating resin layers can be cured together after forming the (N+1)th insulating resin layer. The (N+1)th insulating resin layer may or may not contain maleimide resin. Furthermore, the second to (N+1)th insulating resin layers may contain resins other than maleimide resin.

[0073] The buildup layer is formed from a curable resin composition. The method for forming the buildup layer is not particularly limited, but from the viewpoint of excellent production efficiency, the buildup layer may be formed by laminating the curable resin composition that forms the buildup layer as a resin film on the insulating resin layer that forms the buildup layer.

[0074] The curable resin composition forming the build-up layer may contain a maleimide resin, or may contain one or more other resins or crosslinking agents other than the maleimide resin. Examples of the other resins and crosslinking agents include epoxy resins, phenolic resins, (meth)acrylic resins, and benzoxazines. From the viewpoint of excellent adhesion and dielectric properties, the curable resin composition forming the build-up layer may contain a maleimide resin. Examples of the maleimide resin, other resins, and crosslinking agents include the same as those listed above as the maleimide resin, other resins, and crosslinking agents contained in the first insulating resin layer.

[0075] From the viewpoint of excellent adhesion and dielectric properties, each buildup layer may contain 60% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass of maleimide resin, based on the total amount of maleimide resin, other resins, and crosslinking agent in each buildup layer.

[0076] The build-up layer may contain components other than the maleimide resin, other resins, and cross-linking agents, including the same components as those listed above as other components that may be contained in the first insulating resin layer.

[0077] From the viewpoint of achieving better dielectric properties, the total content of the maleimide resin, other resin, and crosslinking agent in each buildup layer, when the total amount of each buildup layer is taken as 100 parts by mass, is preferably more than 50 parts by mass, and may be 60 parts by mass or more, 80 parts by mass or more, 90 parts by mass or more, 95 parts by mass or more, or 100 parts by mass, or may be 55 to 99 parts by mass, 60 to 96 parts by mass, 70 to 92 parts by mass, or 80 to 90 parts by mass.

[0078] The thickness of each layer of the build-up layer may be 1 μm or more and 200 μm or less. The thickness of each layer of the build-up layer may be the same or different.

[0079] In the build-up process, a circuit may be formed each time an insulating resin layer is formed, or on one or more predetermined insulating resin layers. The method for forming a circuit on an insulating resin layer is not particularly limited, and examples thereof include the methods exemplified in the second process described above.

[0080] In the build-up process, a substrate may be laminated instead of an insulating resin layer, or one or more insulating resin layers and one or more substrates may be laminated. When one or more insulating resin layers and one or more substrates are laminated in the build-up process, the order in which the insulating resin layers and the substrates are laminated is not particularly limited, and for example, they may be laminated alternately. When one or more insulating resin layers and one or more substrates are laminated in the build-up process, a laminate in which one or more insulating resin layers and one or more substrates are laminated in advance may be laminated.

[0081] (Third Step) In the third step, at least the first insulating resin layer is cured (fully cured). If N insulating resin layers are formed on the first insulating resin layer in the build-up step, the first insulating resin layer and the N insulating resin layers are cured together in the third step. By performing this third step, the insulating resin layers formed in steps prior to the third step are brought into a fully cured (C-stage) state.

[0082] The curing in the third step may be thermal curing or photocuring. The heat treatment temperature and time in the third step may be appropriately adjusted, and may be, for example, heat treatment at 150 to 250°C for about 5 to 240 minutes.

[0083] (Other Steps) In the wiring board manufacturing method according to this embodiment, a build-up step may be further performed after the third step. That is, in the wiring board manufacturing method according to this embodiment, the build-up step may be performed only before the third step, only after the third step, or both before and after the third step. The build-up step performed after the third step is not particularly limited. As with the build-up step performed before the third step described above, all insulating resin layers other than the insulating resin layer formed last may be layers containing maleimide resin, and multiple insulating resin layers may be cured collectively, or each insulating resin layer may be cured one by one. The build-up step performed after the third step may be repeated multiple times. Even in the build-up step performed after the third step, when one or more insulating resin layers and one or more base layers are laminated, a laminate in which one or more insulating resin layers and one or more base layers are previously laminated may be laminated.

[0084] The method for manufacturing a wiring board according to this embodiment may include a step of further laminating a substrate on the insulating resin layer formed last (hereinafter also referred to as a "substrate laminating step") before the third step. The material of the substrate to be laminated in the substrate laminating step is not particularly limited. Examples of materials for the substrate include inorganic materials such as semiconductors, glass, ceramics, LTCC (Low Temperature Co-fired Ceramics), and HTCC (High Temperature Co-fired Ceramics); metals such as aluminum and copper; magnetic materials such as pure iron, Fe—Si alloys, Fe—Al alloys, Permalloy, Sendust, Permendur, soft ferrite, amorphous magnetic alloys, and nanocrystalline magnetic alloys; organic materials such as polyethylene terephthalate, polycarbonate, polyimide, polyphenylene ether, polyphenylene sulfide, polyether ether ketone, polytetrafluoroethylene (PTFE), liquid crystal polymers (LCPs), (meth)acrylic resins, cyclic olefin resins, and epoxy resins; and composites of glass and epoxy resins. The substrate may also be a plastic substrate. From the viewpoint of improving the dielectric properties of the wiring board, the substrates laminated in the substrate laminating step may be glass substrates.

[0085] After the substrate laminating step, any one of the first step, the second step, the build-up step, the third step, and the substrate laminating step, or a combination of two or more of these steps may be further carried out, as necessary.

[0086] The method for manufacturing a wiring board according to this embodiment may include, in a step subsequent to the first step, a step of alternately laminating at least one glass substrate and at least one insulating resin layer on the surface of the first insulating resin layer opposite the glass substrate. In this case, at least one insulating resin layer may contain a maleimide resin. When the insulating resin layer contains a maleimide resin, excellent adhesion between the glass substrate and the insulating resin layer is achieved, eliminating the need for an adhesive layer, and resulting in excellent manufacturing efficiency and dielectric properties of the wiring board.

[0087] 2 is a schematic cross-sectional view showing an example of a wiring board manufactured by the wiring board manufacturing method according to the present embodiment. The wiring board 100 includes a glass substrate 10 and a first insulating resin layer 11 containing a maleimide resin. Another insulating resin layer 12 (build-up layer 12) is provided on the surface of the first insulating resin layer 11 opposite the glass substrate 10. Although not shown in FIG. 2 , through electrodes may be formed in the glass substrate 10, and circuits may be formed in the first insulating resin layer 11 and the build-up layer 12. The wiring board 100 may be electrically connected to semiconductor chips such as logic semiconductors (CPUs, GPUs, SoCs, etc.), memory semiconductors (SRAMs, DRAMs, HBMs, etc.), analog semiconductors (analog ICs, RFICs, I / O devices, etc.), and power semiconductors (DC-DC converters, power amplifiers, etc.).

[0088] 3 is a schematic cross-sectional view showing an example of a wiring board manufactured by the wiring board manufacturing method according to this embodiment. The wiring board 200 includes a glass substrate 20, first insulating resin layers 21a and 21b, and buildup layers 22a, 22b, 22c, 22d, 22e, and 22f provided on the surfaces of the first insulating resin layers 21a and 21b opposite the glass substrate 20. The buildup layers 22a, 22b, and 22c and the buildup layers 22d, 22e, and 22f of the wiring board 200 may be formed in the same process or in different processes. For example, the first insulating resin layer 21a and the buildup layers 22a, 22b, and 22c may be cured together, and then the first insulating resin layer 21b and the buildup layers 22d, 22e, and 22f may be formed on the surface of the glass substrate 20 opposite the first insulating resin layer 21a. 3 shows three build-up layers formed on the top and bottom of the glass substrate 20, but the number of build-up layers is not limited to this. Furthermore, at least one of the first insulating resin layers 21a and 21b may be a layer that does not contain maleimide resin (an insulating resin layer that does not fall under the category of the first insulating resin layer).

[0089] Through electrodes 23a, 23b, 23c, and 23d are formed in glass substrate 20. Circuits 24 are formed in each insulating resin layer, and bumps 25 are formed on one surface of wiring board 200 for electrically connecting circuit 24 of wiring board 200 to a package substrate, motherboard, or the like (not shown). Electrical connection to a semiconductor chip or the like (not shown) is made by a method such as a ball grid array (BGA), microbumps, bumpless Cu-Cu bonding, or hybrid bonding (Cu-Cu direct bonding).

[0090] The bumps electrically connect the wiring board and the semiconductor chip, the multilayer substrate and the interposer, and the multilayer substrate and the motherboard. Examples of materials for forming the bumps include conductors such as solder.

[0091] FIG. 4 is a schematic cross-sectional view illustrating an example of a wiring board manufactured by the wiring board manufacturing method according to this embodiment. The wiring board 300 includes glass substrates 30a and 30b and insulating resin layers 38a, 38b, and 38c stacked alternately. In the wiring board 300 shown in FIG. 4 , one of the insulating resin layers 38a, 38b, and 38c is a first insulating resin layer, and the remaining two are build-up layers. While the first insulating resin layer and the build-up layer may be cured separately, it is preferable to simultaneously cure all of the insulating resin layers 38a, 38b, and 38c to improve manufacturing efficiency. Although not shown in FIG. 4 , through-hole electrodes may be formed in the glass substrates 30a and 30b, circuits may be formed in the insulating resin layers 38a, 38b, and 38c, and the wiring board 300 may be electrically connected to a semiconductor chip. While FIG. 4 illustrates a two-layer substrate, the number of layers of the substrate is not limited thereto.

[0092] [Wiring Board] The wiring board according to this embodiment includes a glass substrate and a first insulating resin layer in direct contact with the glass substrate, the first insulating resin layer containing a maleimide resin. The insulating resin layer containing a maleimide resin has excellent adhesion to glass and copper, eliminating the need for bonding to the glass substrate via an adhesive layer as in the past, and can be formed so as to be in direct contact with the glass substrate. Furthermore, the insulating resin layer containing a maleimide resin also has excellent dielectric properties. Therefore, the wiring board according to this embodiment has excellent adhesion between the insulating resin layer and the glass substrate and good dielectric properties.

[0093] Examples of the glass substrate and maleimide resin include the glass substrate and maleimide resin described above.

[0094] The wiring board according to the present embodiment may further include an insulating resin layer containing maleimide resin on a side surface of the glass substrate. The insulating resin layer on the side surface of the glass substrate may be integral with the first insulating resin layer.

[0095] The wiring board according to the present embodiment may further include an insulating resin layer containing a maleimide resin on the surface of the glass substrate opposite to the first insulating resin layer, and the insulating resin layer on the surface of the glass substrate opposite to the first insulating resin layer may be integral with the insulating resin layer formed on the side of the glass substrate.

[0096] When the insulating resin layer on the side surface of the glass substrate is integral with the first insulating resin layer, and the insulating resin layer on the surface of the glass substrate opposite the first insulating resin layer is integral with the insulating resin layer on the side surface of the glass substrate, the glass substrate is covered with an insulating resin layer containing maleimide resin.

[0097] In the wiring board according to this embodiment, a circuit may be formed in the first insulating resin layer. In the wiring board according to this embodiment, since the first insulating resin layer contains maleimide resin, circuit processing is easier even before the first insulating resin layer is fully cured (e.g., in a B-stage state) compared to an insulating resin layer that does not contain maleimide resin. Therefore, it is not necessary to perform a curing process each time an insulating resin layer is laminated, as in the conventional manufacturing method. Therefore, the wiring board according to this embodiment can be efficiently manufactured with fewer curing processes than conventional wiring boards. Examples of methods for forming a circuit include the method exemplified in the second step described above.

[0098] The wiring board according to the present embodiment may further include one or more other insulating resin layers on the surface of the first insulating resin layer opposite to the glass substrate, the one or more other insulating resin layers being formed from a curable resin composition.

[0099] The curable resin composition forming the other insulating resin layer may contain a maleimide resin as a resin component, or may contain a resin other than maleimide resin. Examples of the other resin include epoxy resin, phenolic resin, (meth)acrylic resin, and benzoxazine. The curable resin composition forming the other insulating resin layer may contain one or more other resins as a resin component. From the viewpoint of excellent dielectric properties, the curable resin composition forming the other insulating resin layer may contain a maleimide resin as a resin component. Examples of the maleimide resin include the same maleimide resins as those listed as the maleimide resin contained in the first insulating resin layer described above. When the other insulating resin layer has two or more layers, the curable resin compositions forming the other insulating resin layers may be the same or different.

[0100] The wiring board according to this embodiment further includes a laminate in which at least one glass substrate and at least one insulating resin layer are alternately stacked on a surface of the first insulating resin layer opposite the glass substrate, the first insulating resin layer being in direct contact with one glass substrate in the laminate, and all of the insulating resin layers in the laminate may contain a maleimide resin. Such a wiring board has a structure in which glass substrates and insulating resin layers are alternately stacked, as in the wiring board shown in FIG.

[0101] The number of glass substrates and the number of insulating resin layers in the laminate are not particularly limited, and may be one layer, two layers, or three or more layers.

[0102] The other insulating resin layers and the insulating resin layers in the laminate may each have a circuit formed therein. Examples of a method for forming the circuit include the methods exemplified in the second step described above.

[0103] The wiring board according to this embodiment can be manufactured by the above-described method for manufacturing a wiring board.

[0104] [Curable Resin Composition] The curable resin composition according to this embodiment is a curable resin composition for forming a first insulating resin layer in a wiring board including a glass substrate and a first insulating resin layer in direct contact with the glass substrate, and contains a maleimide resin. Examples of the maleimide resin include the maleimide resins described above. According to the curable resin composition according to this embodiment, the insulating resin layer formed from the curable resin composition has excellent adhesion to glass and copper, so that it can be formed in direct contact with the glass substrate, eliminating the need for bonding to the glass substrate via an adhesive layer as in the past. Furthermore, the insulating resin layer containing the maleimide resin has excellent dielectric properties. Therefore, according to the curable resin composition according to this embodiment, a wiring board can be manufactured that has excellent adhesion between the insulating resin layer and the glass substrate and an insulating resin layer with good dielectric properties.

[0105] The curable resin composition according to the present embodiment may contain, as a resin component, a resin other than the maleimide resin, such as an epoxy resin, a phenolic resin, a (meth)acrylic resin, or a benzoxazine.

[0106] From the viewpoint of achieving better adhesion and dielectric properties, the content of the maleimide resin in the curable resin composition according to this embodiment may be 60% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass based on the total amount of resin components in the curable resin composition.

[0107] From the viewpoint of achieving better adhesion and dielectric properties, the content of the maleimide resin is preferably more than 50 parts by mass, and may be 60 parts by mass or more, 80 parts by mass or more, 90 parts by mass or more, 95 parts by mass or more, or 100 parts by mass, or may be 55 to 99 parts by mass, 60 to 96 parts by mass, 70 to 92 parts by mass, or 80 to 90 parts by mass, when the total amount of the curable resin composition is 100 parts by mass.

[0108] The curable resin composition may contain other components in addition to the resin component, such as the components listed above as other components that may be contained in the first insulating resin layer.

[0109] The preparation means, conditions, etc. of the curable resin composition are not particularly limited. For example, a method may be used in which predetermined amounts of each main component are thoroughly and uniformly stirred and mixed using a mixer or the like, and then kneaded using a mixing roll, an extruder, a kneader, a roll, an extruder, etc. The kneading method is not particularly limited.

[0110] From the viewpoint of coatability, the viscosity of the curable resin composition according to this embodiment at 25°C may be 400 to 4000 mPa s, 400 to 3000 mPa s, or 500 to 2000 mPa s. The viscosity of the curable resin composition at 25°C can be measured using an E-type viscometer.

[0111] The present disclosure will be described in more detail with reference to the following reference examples, although the present disclosure is not limited to these reference examples.

[0112] <Preparation of Maleimide Resin and Curable Resin Composition> (Preparation Example 1) A 2L pressure-resistant SUS container (manufactured by Todoroki Sangyo Co., Ltd.) equipped with a cooling tube, a separation tank, a nitrogen inlet tube, a thermocouple, and a stirrer, and equipped with equipment capable of carrying out a reaction under pressure while refluxing the solvent, was charged with 111 parts by mass of pyromellitic dianhydride (manufactured by Daicel Corporation, PMDA), 907 parts by mass of toluene (manufactured by Wako Pure Chemical Industries, Ltd.), and 200 parts by mass of methanol (manufactured by Daishin Chemical Co., Ltd.). Next, nitrogen gas was introduced into the container and pressurized to a gauge pressure of 250 kPa, after which the temperature was raised to 80 ° C. and maintained at that temperature for 0.5 hours. Subsequently, 368 parts by mass of dimer diamine (trade name "PRIAMINE 1075", manufactured by Croda Japan Co., Ltd.) was added dropwise at a rate of 12.3 g / min. After the dropwise addition, the mixture was maintained at 80 ° C. for 0.5 hours, and then 9.2 parts by mass of methanesulfonic acid was added. The temperature was then raised to 160°C while removing the alcohol-based solvent from the reaction solution. After the temperature was raised, a dehydration ring-closing reaction was carried out at 160°C for 2 hours, and the water and alcohol-based solvent were removed from the reaction solution, yielding a solution containing an intermediate polyimide resin. Subsequently, the resulting solution containing the polyimide resin was cooled to 130°C, and 50 parts by mass of maleic anhydride (manufactured by Fuso Chemical Co., Ltd.) was added. The temperature was then raised to 160°C. After the temperature was raised, a dehydration ring-closing reaction was carried out at 160°C for 4 hours, and the water in the reaction solution was removed, yielding a solution containing maleimide resin (A-1a).

[0113] The obtained solution containing maleimide resin (A-1a) was placed in a separatory funnel, and 1,200 parts by mass of pure water was added. The separatory funnel was shaken and allowed to stand. After standing, the organic layer and the aqueous layer were separated, and only the organic layer was recovered. The recovered organic layer was placed in a 1 L glass container equipped with a cooler, a nitrogen inlet tube, a thermocouple, a stirrer, and a vacuum pump, and the temperature was raised to 88 to 93°C. After removing the water, the temperature was raised to 115°C and the solvent was partially removed for 0.5 hours to obtain a curable resin composition (A-1).

[0114] (Preparation Example 2) Into a 0.3 L flask equipped with a condenser, a separation tank, a nitrogen inlet tube, a thermocouple, and a stirrer, 31.22 parts by mass of BISDA (4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (manufactured by SABIC, trade name "SD1100P-1000"), 126.36 parts by mass of pseudocumene (manufactured by Toyo Gosei Co., Ltd.), 27.65 parts by mass of Solmix A-11 (trade name, manufactured by Japan Alcohol Sales Co., Ltd., alcohol-based solvent), and 29.99 parts by mass of γ-butyrolactone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added. After addition, the temperature was raised to 80°C and kept at 80°C for 0.5 hours, and 21.59 parts by mass of dimer diamine (trade name "PRIAMINE 1075", manufactured by Croda Japan Co., Ltd.) was added dropwise. After the dropwise addition, 13.94 parts by mass of BAFL (9,9-bis(4-aminophenyl)fluorene) was added. Then, 4.00 parts by mass of methanesulfonic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and the temperature was raised to 160°C. After the temperature was raised, 40.00 parts by mass of toluene (Yamaichi Chemical Industry Co., Ltd.) was added, and a dehydration ring-closing reaction was carried out at 160°C for 2 hours. The water and alcohol solvent in the reaction solution were removed, and a solution containing an intermediate polyimide resin was obtained. Subsequently, the resulting solution containing the polyimide resin was cooled to 130°C, and 5.93 parts by mass of maleic anhydride (manufactured by Fuso Chemical Co., Ltd.) was added. The temperature was raised to 160°C, and a dehydration ring-closing reaction was carried out for 4 hours. The water in the reaction solution was removed, and a solution containing maleimide resin (A-2a) was obtained.

[0115] The obtained maleimide resin (A-2a) was placed in a separatory funnel, and 500 parts by mass of pure water was added. The separatory funnel was shaken and allowed to stand. After standing, the aqueous layer and the organic layer separated, and only the organic layer was recovered. The recovered organic layer was placed in a 0.3 L glass vessel equipped with a cooler, a nitrogen inlet tube, a thermocouple, a stirrer, and a vacuum pump, heated to 88 to 93°C, and after removing the water, heated to 100°C. The solvent was partially removed for 0.5 hours under a reduced pressure of 0.1 MPa from atmospheric pressure, to obtain a curable resin composition (A-2).

[0116] (Preparation Example 3) A solution of curable resin composition (A-3) was obtained in the same manner as in Preparation Example 2, except that BISDA (4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride was changed to 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (manufactured by JFE Chemical Corporation, trade name "BPAF")), BAFL (9,9-bis(4-aminophenyl)fluorene) was changed to norbornanediamine (manufactured by Mitsui Fine Chemicals, Inc., trade name "NBDA"), and the blending amounts of each component were changed as shown in Table 1.

[0117] The weight average molecular weight (Mw) of the maleimide resins and the solid content of the curable resin compositions obtained in Preparation Examples 1 to 3 were determined by the following methods. The results are shown in Table 1.

[0118] [Weight-average molecular weight (Mw) of maleimide resin] The weight-average molecular weight of the maleimide resin was measured by gel permeation chromatography (GPC). A sample prepared by dissolving maleimide resin in tetrahydrofuran (THF) to a concentration of 3% by mass was injected in an amount of 50 μL into a column (one GL-R420 (Hitachi High-Tech Fielding Corporation), one GL-R430 (Hitachi High-Tech Fielding Corporation), and one GL-R440 (Hitachi High-Tech Fielding Corporation)) heated to 30°C. Measurement was performed using THF as the developing solvent at a flow rate of 1.6 mL / min. The detector used was an L-3350 RI detector (Hitachi, Ltd.), and the weight-average molecular weight (Mw) was calculated from the elution time using a molecular weight / elution time curve prepared using standard polystyrene (Tosoh Corporation).

[0119] [Solid content of curable resin composition] Curable resin composition X １ g to weight Z １ The weight of the aluminum dish (including the remaining resin composition) after heating at 150°C for 0.5 hours is Z ２ g, the solid content (mass%) was calculated using the following formula: Solid content (mass%) = {(Z ２ -Z １ ) / X １} x 100

[0120]

[0121] <Preparation of Laminate Including B-Stage Film Containing Maleimide Resin> The following components were prepared for preparation of a laminate including a B-stage film containing a maleimide resin. Inorganic filler: 5SM-CK2 (manufactured by Admatechs Co., Ltd., silica mass 70%, average particle size 0.5 μm, methyl isobutyl ketone dispersion) Polymerization initiator: Percumyl D (manufactured by NOF Corporation, dicumyl peroxide) Organic solvent: Cyclopentanone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) MIBK (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., methyl isobutyl ketone)

[0122] (Laminate (1)) 0.589 g of Percumyl D, a polymerization initiator, was blended with 100 g of the curable resin composition (A-1) to prepare a resin composition. Next, using an applicator, the resin composition was applied to a support film (polyethylene terephthalate film, manufactured by Toyobo Co., Ltd., trade name "A5300", film thickness 50 μm) so as to have a thickness of 25 μm after drying, and the composition was dried in a dryer at 120°C for 10 minutes. Thereafter, a UV irradiator (a UV irradiator with a conveyor, manufactured by GS Yuasa Corporation, using a metal halide lamp (MAL 500NAL)) was used to irradiate the composition from the support film side at 100 mW / cm. ２ , 150 mJ / cm ２ A laminate (1) was produced comprising a support film and a film in a B-stage state (semi-cured state).

[0123] (Laminates (2) to (5)) Laminates (2) to (5) were produced in the same manner as laminate (1), except that the type of curable resin composition and the amount of each component (unit: g) were changed as shown in Table 2.

[0124]

[0125] <Preparation of cured film containing maleimide resin> (Cured film (B-1)) A Cu foil (manufactured by Mitsui Mining & Smelting Co., Ltd., trade name "3EC-M2S-VLP") was attached to the B-stage (semi-cured) film in the laminate (1) using a vacuum laminator under conditions of 100 ° C., 120 seconds, -100 kPa, to obtain an adhesive sheet (1) having a support film / B-stage film / copper foil configuration. Thereafter, the support film of the adhesive sheet (1) was peeled off, and a curing treatment was carried out for 60 minutes at 200 ° C. using a nitrogen dryer (manufactured by Yamato Scientific Co., Ltd., model number: DN410I) in a nitrogen atmosphere. After curing, the copper foil was removed by etching with an aqueous ammonium persulfate solution and dried at 105 ° C. for 30 minutes to produce a cured film (B-1).

[0126] (Cured Films (B-2) to (B-5)) Cured films (B-2) to (B-5) were produced in the same manner as cured film (1), except that laminate (1) was replaced by laminates (2) to (5).

[0127] <Preparation of Maleimide Resin-Free Cured Films> The following materials were prepared as maleimide resin-free cured films: B-6: Liquid crystal polymer (LCP) film (manufactured by Kuraray Co., Ltd., product name "Vextar", product number "CTQ-100") B-7: PTFE film (manufactured by Nitto Denko Corporation, product name "Nitoflon", product number "#900UL")

[0128] [Adhesion to Copper Foil or Glass Substrate] <Preparation of Test Pieces for Measuring Adhesive Strength> (Reference Example 1) A low-roughness copper foil (manufactured by Furukawa Electric Co., Ltd., product name: FZ-WS-18) or a smooth copper foil (manufactured by Fukuda Metal Foil & Powder Co., Ltd., product name: CF-T9DA-SV-18) was bonded to the B-stage (semi-cured) film in the laminate (1) using a vacuum laminator under conditions of 100°C, 120 seconds, and -100 kPa, to obtain an adhesive sheet (1-2a) having a configuration of support film / B-stage film / low-roughness copper foil and an adhesive sheet (1-2b) having a configuration of support film / B-stage film / smooth copper foil. Thereafter, the support film of the adhesive sheets (1-2a) and (1-2b) was peeled off, and in a vacuum laminator, the B-stage film of the adhesive sheet (1-2a) was placed on a low-roughness copper foil (manufactured by Furukawa Electric Co., Ltd., product name: FZ-WS-18), and the B-stage film of the adhesive sheet (1-2b) was placed on a smooth copper foil (manufactured by Fukuda Metal Foil and Powder Co., Ltd., product name: CF-T9DA-SV-18), each at 100 ° C., 120 seconds, and -100 kPa. Also, the support film of another adhesive sheet (1-2a) was peeled off, and the B-stage film of the adhesive sheet (1-2a) was placed on a glass substrate (manufactured by AGC Inc., product name: AN-100) at 120 ° C., 240 seconds, and -100 kPa to obtain an adhesive sheet (1-3) having a low-roughness copper foil / B-stage film / glass substrate configuration. The adhesive sheets (1-2a), (1-2b) and (1-3) were cured in a dryer at 200° C. for 60 minutes to prepare test pieces for Reference Example 1.

[0129] (Reference Examples 2 to 5) Test pieces for Reference Examples 2 to 5 were prepared in the same manner as Reference Example 1, except that the laminate (1) was changed to laminates (2) to (5).

[0130] Comparative Reference Example 1 A test piece for Comparative Reference Example 1 was prepared in the same manner as in Reference Example 1, except that a cured film (B-6) was used instead of the film in a B-stage state (semi-cured state), and bonding to a copper foil or a glass substrate was performed using a hand roller on a hot plate at a temperature of 315° C. Note that, because the cured film (B-6) did not adhere to the glass substrate, an adhesive sheet having a configuration of copper foil / cured film (B-6) / glass substrate could not be prepared.

[0131] Comparative Reference Example 2 A test piece for Comparative Reference Example 2 was prepared in the same manner as in Reference Example 1, except that a cured film (B-7) was used instead of the film in a B-stage state (semi-cured state), and bonding to the copper foil was performed using a hand roller on a hot plate at a temperature of 330° C. Note that the cured film (B-7) did not adhere to the smooth copper foil or the glass substrate, and therefore an adhesive sheet having a configuration of smooth copper foil / cured film (B-7) / smooth copper foil or glass substrate could not be prepared.

[0132] <Measurement of Adhesion Strength> The adhesive strength of the prepared test pieces was measured. The adhesive strength was measured using a 90° peel tester (Yamaden Co., Ltd., RHEONER II CREEP METER RE2-3305B) by peeling the cured film from a smooth copper foil, a low-roughening copper foil, or a glass substrate at 90° at room temperature at a pulling rate of 5 mm / s to measure the adhesive strength between the cured film and the copper foil or glass substrate, and evaluated according to the following evaluation criteria. The results are shown in Table 3.

[0133] <Evaluation criteria for adhesive strength> A: adhesive strength of 1.0 kN / m or more B: adhesive strength of 0.5 kN / m or more but less than 1.0 kN / m C: adhesive strength less than 0.5 kN / m

[0134]

[0135] [Dielectric Properties] The relative dielectric constant (Dk) and dielectric loss tangent (Df) of the cured film were measured by the following procedure.

[0136] <Measurement of Relative Dielectric Constant (Dk) and Dielectric Loss Tangent (Df)> (Reference Examples 6 to 10 and Comparative Reference Examples 3 and 4) 50 mm x 50 mm test specimens were prepared using cured films (B-1) to (B-7). These test specimens were dried in a 105°C dryer for 30 minutes and then left at room temperature (25°C) and 52% humidity for 24 hours. The relative dielectric constant (Dk) and dielectric loss tangent (Df) were then measured from 20 to 100 GHz by the balanced disc resonator method (BCDR method) using a network analyzer (product name "P5003A", manufactured by KEYSIGHT Technologies) and a split cylinder resonator (manufactured by KEYSIGHT Technologies). The results are shown in Table 4.

[0137]

[0138] Example 1 [Preparation of Multilayer Substrate 1] First, a film in a B-stage state (semi-cured state) of the laminate (1) was bonded to a glass substrate A (alkali-free glass "Eagle XG" manufactured by Corning Incorporated, 0.5 mm thick) cut to a length of 5 cm on a side using a vacuum laminator under conditions of 130°C, 90 seconds, and -100 kPa, to obtain an adhesive sheet (1-4) having a glass substrate A / film in a B-stage state / support film configuration. Two sheets of this adhesive sheet (1-4) and one sheet of glass substrate B (alkali-free glass "Eagle XG" manufactured by Corning Incorporated, 0.5 mm thick) cut to a length of 5 cm on a side were prepared.

[0139] Next, the support film of adhesive sheet (1-4) was peeled off, and the adhesive sheet was placed so that the film side in the B-stage state faced the glass substrate B, thereby preparing a structure (1) of glass substrate B / film in the B-stage state / glass substrate A. Furthermore, the support film of another adhesive sheet (1-4) was peeled off, and the adhesive sheet was placed so that the film side in the B-stage state faced the glass substrate A of the structure (1), thereby preparing a structure (2) of glass substrate B / film in the B-stage state / glass substrate A / film in the B-stage state / glass substrate A.

[0140] The component (2) was then subjected to a pressure curing treatment at 2.5 KN, 200°C, and 10 minutes in a heat and pressure device (20 KN SE work hot plate press WHP-2-300, manufactured by Kosei Hydraulic Machinery Co., Ltd.), to produce a multilayer substrate 1 as shown in FIG. 4. The multilayer substrate 1 was efficiently produced by curing the component (2) all at once under heat and pressure. Furthermore, no peeling between the substrate and the film was observed in the obtained multilayer substrate 1.

[0141] 100, 200, 300...wiring board, 10, 20, 30a, 30b...glass substrate, 11, 21a, 21b...first insulating resin layer, 12, 22a, 22b, 22c, 22d, 22e, 22f...insulating resin layer (build-up layer), 23a, 23b, 23c, 23d...through electrode, 24...circuit, 25...bump, 38a, 38b, 38c...insulating resin layer.

Claims

1. A method for manufacturing a wiring board, comprising a first step of forming a first insulating resin layer containing a maleimide resin on a glass substrate so that the glass substrate and the first insulating resin layer are in direct contact with each other.

2. The manufacturing method according to claim 1, further comprising: a second step of forming a circuit in the first insulating resin layer after the first step; and a third step of curing at least the first insulating resin layer after the second step.

3. The manufacturing method according to claim 2, further comprising the step of forming one or more other insulating resin layers on the surface of the first insulating resin layer opposite to the glass substrate after the second step and before the third step.

4. A wiring board comprising a glass substrate and a first insulating resin layer in direct contact with the glass substrate, wherein the first insulating resin layer contains a maleimide resin.

5. The wiring board according to claim 4, wherein a circuit is formed on said first insulating resin layer.

6. The wiring board according to claim 4 or 5, further comprising one or more other insulating resin layers on the surface of said first insulating resin layer opposite said glass substrate.

7. A curable resin composition for forming a first insulating resin layer in a wiring board having a glass substrate and a first insulating resin layer in direct contact with the glass substrate, the curable resin composition containing a maleimide resin.

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