Laminated structure, cured product, electronic component and cured product formation method

Abstract

To provide a laminated structure which is excellent in developability and also excellent in laminate property and edge covering property.SOLUTION: A laminated structure includes a first film, a resin layer, and a second film in this order, wherein the resin layer includes a resin layer (A) in contact with the first film, and a resin layer (B) in contact with the second film, the resin layer (A) contains an alkali-soluble resin having an imide ring, a photopolymerization initiator, and a thermosetting resin, the resin layer (B) contains an alkali-soluble resin having no imide ring, a polyfunctional photopolymerizable monomer, inorganic particles, and a thermosetting resin, melt viscosities at 50°C and 100°C of the resin layer (A) and the resin layer (B) are within specific numerical ranges, and the total thickness of the resin layer (A) and the resin layer (B) is more than 80 μm and 300 μm or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminate structure. The present invention also relates to a cured product formed using the laminate structure, an electronic component including the same, and a method for forming the cured product. [Background technology]

[0002] Generally, when mounting electronic components on a printed wiring board used in electronic devices, a solder resist layer is formed on the substrate on which the circuit pattern is formed in an area excluding connection holes in order to prevent solder from adhering to unnecessary areas.

[0003] As electronic devices have become lighter, thinner, and smaller in recent years, printed wiring boards have become more precise and dense. Currently, solder resist layers are typically formed using so-called photosolder resists. This process involves applying a liquid photosensitive resin composition to a substrate, drying it, exposing it to light, and developing it to form a pattern. The patterned resin is then cured by heating or light irradiation. Furthermore, power electronics boards used in traction motor systems for electric vehicles (EVs) are primarily "thick copper circuit boards" with thick circuits due to the large currents that flow through the circuits. Various methods for forming solder resist on such thick copper circuit boards have been devised. For example, methods have been proposed in which gap-filling ink is applied between circuits, followed by flattening before forming solder resist, and methods that effectively cover the edges of circuits using special spray coating equipment. However, a simple and easy-to-use method has yet to be established.

[0004] On the other hand, it has also been proposed to form a solder resist layer using a laminate structure (photosensitive film) having a photosensitive resin layer (photosensitive layer) without using the liquid photosensitive resin composition described above. Such a laminate structure generally has a photosensitive resin layer formed from a photosensitive resin composition on a support film. Such a laminate structure can be laminated to a wiring board by thermocompression bonding, and before exposure or after exposure from the support film side, the support film can be peeled off and development can be performed to form a patterned solder resist layer.

[0005] For example, Patent Document 1 discloses a photosensitive film having at least a support and a photosensitive layer on the support, wherein the photosensitive layer is made of a photosensitive composition containing at least a binder having a crosslinkable group, the amount of a catalyst remaining for introducing the crosslinkable group into the binder is 200 ppm or less, and the melt viscosity at 24°C is 1.0 × 10 5 Pa·s~1.0×10 7 Pa·s and a melt viscosity of 1.0×10 at 60°C to 90°C 2 Pa·s~5.0×10 4 The photosensitive film is characterized in that the film has a film thickness of 1.6 Pa·s, and when the photosensitive film is wound into a roll, the winding tension is 1.6 kg / 10 cm or more, and the roll has end pressers on both end surfaces. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-237494 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the inventors have found that when the circuit thickness of a printed wiring board is large (e.g., 70 μm), poor embedding occurs due to excessive or insufficient melt viscosity. Specifically, they have found that when the melt viscosity of the resin layer is high at low temperatures (e.g., 50°C), poor embedding (lamination) occurs due to the high viscosity during lamination. On the other hand, they have found that when the melt viscosity of the resin layer is low at high temperatures (e.g., 100°C), the low viscosity causes the film at the edge of the circuit to become thin, i.e., the edge coverage is reduced. Since poor embedding leads to a reduction in the flatness of the resin layer, and reduced edge coverage leads to deterioration in chemical resistance and heat resistance in subsequent processes, a dry film with excellent lamination and edge coverage is desired.

[0008] Patent Document 1 discloses a photosensitive film that can fill gaps of 1 μm to 40 μm without introducing air bubbles at 60 to 90°C. Meanwhile, the circuit thickness of thick copper wiring boards for high current and high voltage used in electric vehicles and servers in recent years is approximately 50 μm to 250 μm. Therefore, the film described in Patent Document 1 has issues with lamination to these thick copper circuits and edge covering.

[0009] Therefore, an object of the present invention is to provide a laminate structure having excellent developability, lamination properties, and edge covering properties. Another object of the present invention is to provide a cured product formed using the laminate structure, an electronic component including the same, and a method for forming the cured product. [Means for solving the problem]

[0010] As a result of intensive research aimed at achieving the above object, the present inventors have found that the above problems can be solved by using a laminate having resin layers (A) and (B) with different melt viscosities in a laminate structure including, in order, a first film, a resin layer, and a second film. Specifically, the inventors have found that by adjusting the melt viscosities of the resin layers (A) and (B) in the resin layers to specific values ​​at 50°C and 100°C, respectively, it is possible to provide a laminate structure in which the resin layer (B) can be embedded between circuits in a printed wiring board after lamination, and in which the presence of the resin layer (A) prevents the film at the edge of the circuit from becoming thin and maintains smoothness.

[0011] That is, according to the present invention, the following inventions are provided. [1] A laminated structure including a first film, a resin layer, and a second film in this order, the resin layer includes a resin layer (A) in contact with the first film and a resin layer (B) in contact with the second film, the resin layer (A) contains an alkali-soluble resin having an imide ring, a photopolymerization initiator, and a thermosetting resin, the resin layer (B) contains an alkali-soluble resin having no imide ring, a polyfunctional photopolymerizable monomer, inorganic particles, and a thermosetting resin; the resin layer (A) has a melt viscosity at 50°C of 80,000 Pa s or more and 110,000 Pa s or less, and a melt viscosity at 100°C of 2,000 Pa s or more and 3,500 Pa s or less, the melt viscosity of the resin layer (B) at 50°C is 1000 Pa s or more and 50000 Pa s or less, and the melt viscosity at 100°C is 50 Pa s or more and 2000 Pa s or less, A laminated structure, characterized in that the total thickness of the resin layer (A) and the resin layer (B) is more than 80 μm and 300 μm or less. [2] The laminate structure according to [1], wherein the melt viscosity of the resin layer (A) at 50°C is 90,000 Pa·s or more and 105,000 Pa·s or less, and the melt viscosity at 100°C is 2,200 Pa·s or more and 3,200 Pa·s or less. [3] The laminate structure according to [1] and [2], wherein the ratio of the melt viscosity at 50°C to the melt viscosity at 100°C (50°C / 100°C) of the resin layer (A) is 30 or more and 40 or less. [4] The laminate structure according to any one of [1] to [3], wherein the melt viscosity of the resin layer (B) at 50°C is 3000 Pa·s or more and 40000 Pa·s or less, and the melt viscosity at 100°C is 200 Pa·s or more and 1600 Pa·s or less. [5] The laminate structure according to any one of [1] to [4], wherein the ratio of the melt viscosity at 50°C to the melt viscosity at 100°C (50°C / 100°C) of the resin layer (B) is 10 or more and 100 or less. [6] The laminate structure according to any one of [1] to [5], wherein the thickness of the resin layer (A) alone is 1 μm or more and 25 μm or less. [7] The laminate structure according to any one of [1] to [6], wherein the inorganic particles contained in the resin layer (B) contain an inorganic filler. [8] The laminate structure according to any one of [1] to [7], wherein the content of the inorganic filler contained in the resin layer (B) is 10% by mass or more and 80% by mass or less in terms of solid content based on the total amount of the resin layer (B). [9] The laminate structure according to [7] or [8], wherein the inorganic filler contained in the resin layer (B) has an average particle size of 0.02 μm or more and 10 μm or less.

[10] A cured product obtained by curing the resin layer in the laminate structure according to any one of [1] to [9].

[11] An electronic component comprising the cured product according to

[10] .

[12] A step of peeling off the second film in the laminate structure according to any one of [1] to [9], bonding the resin layer (B) to a substrate on which a circuit has been formed, and arranging the first film and the resin layer on the substrate; an exposure step of irradiating a predetermined portion of the resin layer with active energy rays through the first film; a first heating step of heating the resin layer after the exposure step; a development step of peeling off the first film from the resin layer after the first heating step and removing a region of the resin layer after the exposure step that has not been irradiated with active energy rays; and a second heating step of heating the resin layer after the developing step; A method for forming a cured product, comprising: [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a laminate structure having excellent developability, lamination property, and edge covering property. Furthermore, according to the present invention, it is possible to provide a cured product formed using the laminate structure and an electronic component including the same, i.e., an electronic component having the cured product as a protective film, for example, a coverlay, a solder resist, or an interlayer insulating material, and a method for forming the cured product. DETAILED DESCRIPTION OF THE INVENTION

[0013] <Laminated structure> The laminate structure according to the present invention is a laminate structure including a first film, a resin layer, and a second film in this order, the resin layer includes a resin layer (A) in contact with the first film and a resin layer (B) in contact with the second film, the resin layer (A) contains an alkali-soluble resin having an imide ring, a photopolymerization initiator, and a thermosetting resin, the resin layer (B) contains an alkali-soluble resin having no imide ring, a polyfunctional photopolymerizable monomer, inorganic particles, and a thermosetting resin; the resin layer (A) has a melt viscosity at 50°C of 80,000 Pa s or more and 110,000 Pa s or less, and a melt viscosity at 100°C of 2,000 Pa s or more and 3,500 Pa s or less, the melt viscosity of the resin layer (B) at 50°C is 1000 Pa s or more and 50000 Pa s or less, and the melt viscosity at 100°C is 50 Pa s or more and 2000 Pa s or less, The laminated structure is characterized in that the total thickness of the resin layer (A) and the resin layer (B) is more than 80 μm and 300 μm or less.

[0014] This configuration allows a laminated structure with excellent lamination properties and edge covering properties to be obtained. Furthermore, by using the above-described method for forming a cured product, a cured product with excellent developability can be obtained without impairing edge covering properties.

[0015] [Resin layer] The resin layer is made of a dried coating film of a resin composition and includes a resin layer (A) in contact with the first film and a resin layer (B) in contact with the second film. The resin layer may further include another resin layer between the resin layer (A) and the resin layer (B).

[0016] The thickness of the entire resin layer is more than 80 μm and not more than 300 μm, preferably 90 μm or more and 250 μm or less, and more preferably 95 μm or more and 200 μm or less. When the thickness of the entire resin layer is within the above numerical range, the lamination property and edge covering property are good.

[0017] [Resin layer (A)] The resin layer (A) does not melt at the temperature during lamination, mainly due to its high melt viscosity, and therefore it is possible to suppress a decrease in edge covering properties caused by excessive outflow of the resin layer (B), which has a low melt viscosity. The melt viscosity of the resin layer (A) at 50° C. is 80,000 Pa·s or more and 110,000 Pa·s or less, preferably 90,000 Pa·s or more and 110,000 Pa·s or less, and more preferably 90,000 Pa·s or more and 105,000 Pa·s or less. The melt viscosity of the resin layer (A) at 100°C is 2000 Pa·s or more and 3500 Pa·s or less, preferably 2200 Pa·s or more and 3200 Pa·s or less, and more preferably 2400 Pa·s or more and 3000 Pa·s or less. If the melt viscosity of the resin layer (A) at 50°C and 100°C is within the above range, edge covering properties can be ensured even if excessive outflow of the resin layer (B) occurs. In the present invention, the melt viscosity of the resin layer (A) at 50° C. and 100° C. is a value measured by a dynamic viscoelasticity measuring device, which is a rotational rheometer.

[0018] The ratio of the melt viscosity of the resin layer (A) at 50°C to the melt viscosity at 100°C (melt viscosity at 50°C (Pa·s) / melt viscosity at 100°C (Pa·s)) is preferably 30 or more and 40 or less, more preferably 32 or more and 39 or less. When the ratio of the melt viscosity of the resin layer (A) at 50°C to the melt viscosity at 100°C is within the above range, the change in melt viscosity due to temperature can be suppressed, and the edge covering property can be improved without adversely affecting the lamination property.

[0019] The thickness of the resin layer (A) alone is preferably 1 μm or more and 25 μm or less, more preferably 5 μm or more and 20 μm or less. If the thickness of the resin layer (A) is within the above range, the thickness of the resin layer (A) at the circuit edge portion in the lamination step can be ensured, resulting in good edge covering properties.

[0020] The resin layer (A) contains an alkali-soluble resin having an imide ring, a photopolymerization initiator, and a thermosetting resin, and may further contain other additive components such as a colorant. In the present invention, the melt viscosity of the resin layer (A) at 50°C and 100°C can be adjusted to the above-mentioned preferred range by adjusting the type and content of each component contained in the resin layer (A). The resin layer (A) is formed by applying and drying a resin composition (A1) containing an alkali-soluble resin having an imide ring, a photopolymerization initiator, and a thermosetting resin onto a first film. Each component of the resin layer (A) will be described in detail below.

[0021] (Alkali-soluble resin having an imide ring) The alkali-soluble resin having an imide ring is not particularly limited as long as it has an imide ring and an alkali-soluble group that is soluble in an alkaline aqueous solution, such as a phenolic hydroxyl group, a thiol group, or a carboxyl group.

[0022] For example, a carboxyl group-containing alkali-soluble resin having an imide ring can be obtained by a known, commonly used method for introducing an imide ring into a carboxyl group-containing alkali-soluble resin. For example, a resin obtained by reacting a carboxylic acid anhydride component with an amine component and / or an isocyanate component can be used. Imidization can be carried out by thermal imidization or chemical imidization, or both methods can be used in combination.

[0023] Here, examples of the carboxylic acid anhydride component include tetracarboxylic acid anhydrides and tricarboxylic acid anhydrides, but are not limited to these acid anhydrides, and any compound having an acid anhydride group and a carboxyl group that react with an amino group or an isocyanate group, including derivatives thereof, can be used. Furthermore, these carboxylic acid anhydride components may be used alone or in combination.

[0024] Examples of tetracarboxylic acid anhydrides include pyromellitic dianhydride, 3-fluoropyromellitic dianhydride, 3,6-difluoropyromellitic dianhydride, 3,6-bis(trifluoromethyl)pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 2,2'-difluoro-3,3',4,4'-biphenyltetracarboxylic dianhydride, and 5,5'-difluoro-3,3',4,4'-biphenyltetracarboxylic dianhydride. Acid dianhydrides, 6,6'-difluoro-3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',5,5',6,6'-hexafluoro-3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2'-bis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, 5,5'-bis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, 6,6'-bis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',5,5'-tetrafluoro- hexakis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',6,6'-tetrakis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, 5,5',6,6'-tetrakis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, and 2,2',5,5',6,6'-hexakis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4 "-terphenyltetracarboxylic dianhydride, 3,3'",4,4'"-quaterphenyltetracarboxylic dianhydride, 3,3"",4,4""-quinquephenyltetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethynylidene-4,4'-diphthalic dianhydride, 2,2-propylidene-4,4'-diphthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-Diphthalic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, difluoromethylene-4,4'-diphthalic dianhydride, 1,1,2,2-tetrafluoro-1,2-ethylene-4,4'-diphthalic dianhydride, 1,1,2,2,3,3-hexafluoro-1,3-trimethylene-4,4'-diphthalic dianhydride, 1,1,2,2,3,3,4,4-octafluoro-1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,1,2,2,3,3,4,4,5,5-de Fluoro-1,5-pentamethylene-4,4'-diphthalic dianhydride, thio-4,4'-diphthalic dianhydride, sulfonyl-4,4'-diphthalic dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethylsiloxane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3 -Bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-Anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic) dianhydride, methyl Ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethynylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 2,2-propylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1,1,3,3,3-hexafluoro-2,2-propylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2 -dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 3,3'-difluorooxy-4,4'-diphthalic dianhydride, 5,5'-difluorooxy-4,4'-diphthalic dianhydride, 6,6'-difluorooxy-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-hexafluorooxy-4,4'-diphthalic dianhydride, 3,3'-bis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride Aqueous, 5,5'-bis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 6,6'-bis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 3,3',5,5'-tetrakis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 3,3',6,6'-tetrakis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 5,5',6,6'-tetrakis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-hexakis(trifluoromethyl)oxy-4,4'-Diphthalic dianhydride, 3,3'-difluorosulfonyl-4,4'-diphthalic dianhydride, 5,5'-difluorosulfonyl-4,4'-diphthalic dianhydride, 6,6'-difluorosulfonyl-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-hexafluorosulfonyl-4,4'-diphthalic dianhydride, 3,3'-bis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 5,5'-bis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 6,6'-bis(trifluoromethyl)sulfonyl 3,3',5,5'-Tetrakis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 3,3',6,6'-Tetrakis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 5,5',6,6'-Tetrakis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-Hexakis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 3,3'-Difluoro-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride Aqueous, 5,5'-difluoro-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 6,6'-difluoro-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-hexafluoro-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 3,3'-bis(trifluoromethyl)-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 5,5'-bis(trifluoromethyl)-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 6,6' -Difluoro-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 3,3',5,5'-tetrakis(trifluoromethyl)-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 3,3',6,6'-tetrakis(trifluoromethyl)-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 5,5',6,6'-tetrakis(trifluoromethyl)-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-hexakis(trifluoromethyl)-2,2-Perfluoropropylidene-4,4'-diphthalic dianhydride, 9-phenyl-9-(trifluoromethyl)xanthene-2,3,6,7-tetracarboxylic dianhydride, 9,9-bis(trifluoromethyl)xanthene-2,3,6,7-tetracarboxylic dianhydride, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 9,9-bis[4-(3,4-dicarboxy)phenyl]fluorene dianhydride, 9,9-bis[4-(2,3-dicarboxy)phenyl]fluorene dianhydride, ethylene glycol bistrimellitate dianhydride, 1,2-(ethylene)bis(trimellitate anhydride), 1,3-(trimethylene)bis(trimellitate) bis(trimellitate anhydride), 1,4-(tetramethylene)bis(trimellitate anhydride), 1,5-(pentamethylene)bis(trimellitate anhydride), 1,6-(hexamethylene)bis(trimellitate anhydride), 1,7-(heptamethylene)bis(trimellitate anhydride), 1,8-(octamethylene)bis(trimellitate anhydride), 1,9-(nonamethylene)bis(trimellitate anhydride), 1,10-(decamethylene)bis(trimellitate anhydride), 1,12-(dodecamethylene)bis(trimellitate anhydride), 1,16-(hexadecamethylene)bis(trimellitate anhydride), 1,18-(octadecamethylene)bis(trimellitate anhydride), and the like. Examples of tricarboxylic acid anhydrides include trimellitic anhydride and nuclear-hydrogenated trimellitic anhydride.

[0025] Examples of the amine component include, but are not limited to, diamines such as aliphatic diamines and aromatic diamines, polyamines such as aliphatic polyetheramines, diamines having a carboxylic acid, and diamines having a phenolic hydroxyl group. These amine components may be used alone or in combination.

[0026] Examples of diamines include diamines with one benzene nucleus such as p-phenylenediamine (PPD), 1,3-diaminobenzene, 2,4-toluenediamine, 2,5-toluenediamine, and 2,6-toluenediamine; diaminodiphenyl ethers such as 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, and 3,4'-diaminodiphenyl ether; 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl; '-Bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis(4-aminophenyl)sulfide, 4,4'-diaminobenzanilide, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (o-tolidine), 2,2'-dimethylbenzidine (m-tolidine), 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3 ,4'-Diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-diaminodiphenyl meth , 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-dicarboxy-4,Diamines with two benzene nuclei such as 4'-diaminodiphenylmethane, 1,3-bis(3-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(3-aminophenyl)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3'-diamino-4-(4-phenyl)phenoxybenzophenone, 3,3'-diamino-4,4'-di(4-phenylphenoxy)benzophenone, 1,3-bis(3-aminophenylsulfide)benzene, Diamines with three benzene nuclei such as 1,3-bis(4-aminophenylsulfide)benzene, 1,4-bis(4-aminophenylsulfide)benzene, 1,3-bis(3-aminophenylsulfone)benzene, 1,3-bis(4-aminophenylsulfone)benzene, 1,4-bis(4-aminophenylsulfone)benzene, 1,3-bis[2-(4-aminophenyl)isopropyl]benzene, 1,4-bis[2-(3-aminophenyl)isopropyl]benzene, 1,4-bis[2-(4-aminophenyl)isopropyl]benzene, 3,3'-bis(3-aminophenoxy)biphenyl, 3,3'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, bis[3-(3-aminophenoxy)phenyl]ether, bis[3-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, bis[3-(3-aminophenoxy)phenyl]ketone, bis[3-(4-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[3-(3-aminophenoxy)phenyl]ketone bis[3-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[3-(3-aminophenoxy)phenyl]sulfone, bis[3-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[3-(3-aminophenoxy)phenyl]methane, bis[3-(4-aminophen 2,2-bis[3-(3-aminophenoxy)phenyl]propane, 2,2-bis[3-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3 aromatic diamines such as diamines with four benzene nuclei, such as 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,Examples of the aliphatic diamines include 8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, and 1,2-diaminocyclohexane. Examples of the aliphatic polyetheramines include ethylene glycol and / or propylene glycol-based polyamines.

[0027] Examples of amines having a carboxyl group include diaminobenzoic acids such as 3,5-diaminobenzoic acid, 2,5-diaminobenzoic acid, and 3,4-diaminobenzoic acid, aminophenoxybenzoic acids such as 3,5-bis(3-aminophenoxy)benzoic acid and 3,5-bis(4-aminophenoxy)benzoic acid, 3,3'-diamino-4,4'-dicarboxybiphenyl, 4,4'-diamino-3,3'-dicarboxybiphenyl, 4,4'-diamino-2,2'-dicarboxybiphenyl, and 4,4'-diamino-2,2',5, Carboxybiphenyl compounds such as 5'-tetracarboxybiphenyl, 3,3'-diamino-4,4'-dicarboxydiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 2,2-bis[3-amino-4-carboxyphenyl]propane, 2,2-bis[4-amino-3-carboxyphenyl]propane, 2,2-bis[3-amino-4-carboxyphenyl]hexafluoropropane, 4,4'-diamino-2,2',5,5'-tetracarboxydiphenylmethane, and the like. carboxydiphenylalkanes, carboxydiphenyl ether compounds such as 3,3'-diamino-4,4'-dicarboxydiphenyl ether, 4,4'-diamino-3,3'-dicarboxydiphenyl ether, 4,4'-diamino-2,2'-dicarboxydiphenyl ether, and 4,4'-diamino-2,2',5,5'-tetracarboxydiphenyl ether, 3,3'-diamino-4,4'-dicarboxydiphenyl sulfone, 4,4'-diamino-3,3'-dicarboxydiphenyl sulfone, 4,4'-diamino-4,4'-dicarboxydiphenyl ether, 4,4'-diamino-3,3'-dicarboxydiphenyl ether, 4,4'-diamino-2,2',5,5'-tetracarboxydiphenyl ether, Examples of suitable aryl groups include diphenyl sulfone compounds such as 4,4'-diamino-2,2'-dicarboxydiphenyl sulfone and 4,4'-diamino-2,2',5,5'-tetracarboxydiphenyl sulfone, bis[(carboxyphenyl)phenyl]alkane compounds such as 2,2-bis[4-(4-amino-3-carboxyphenoxy)phenyl]propane, and bis[(carboxyphenoxy)phenyl]sulfone compounds such as 2,2-bis[4-(4-amino-3-carboxyphenoxy)phenyl]sulfone.

[0028] The isocyanate component may be, but is not limited to, aromatic diisocyanates and their isomers and polymers, aliphatic diisocyanates, alicyclic diisocyanates and their isomers, or other general-purpose diisocyanates. These isocyanate components may be used alone or in combination.

[0029] Examples of diisocyanates include aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, biphenyl diisocyanate, diphenyl sulfone diisocyanate, and diphenyl ether diisocyanate, and their isomers and polymers; aliphatic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate; alicyclic diisocyanates and isomers obtained by hydrogenating aromatic diisocyanates; and other general-purpose diisocyanates.

[0030] As the alkali-soluble resin having an imide ring, a carboxyl group-containing alkali-soluble resin having an imide ring and an amide structure can also be used. The carboxyl group-containing resin having an imide structure and an amide structure is preferably a polyamide-imide resin, and can be obtained, for example, by reacting a diamine containing at least a carboxyl group-containing diamine with an acid anhydride (a1) containing an acid anhydride having at least three carboxyl groups, two of which are anhydridized, to obtain an imidized product, and then reacting the obtained imidized product with a reaction raw material containing a diisocyanate compound. As described below, in addition to the imidized product and the diisocyanate compound, the reaction raw material preferably further contains an acid anhydride (a2) having at least three carboxyl groups, two of which are anhydridized.

[0031] Here, the diamine used in the synthesis of the polyamide-imide resin includes at least a carboxyl group-containing diamine, but it is preferable to use a diamine having an ether bond in combination. Examples of carboxyl group-containing diamines include diaminobenzoic acids such as 3,5-diaminobenzoic acid, 2,5-diaminobenzoic acid, and 3,4-diaminobenzoic acid; aminophenoxybenzoic acids such as 3,5-bis(3-aminophenoxy)benzoic acid and 3,5-bis(4-aminophenoxy)benzoic acid; carboxybiphenyl compounds such as 3,3'-methylenebis(6-aminobenzoic acid) and 3,3'-diamino-4,4'-dicarboxybiphenyl; carboxydiphenylalkanes such as 3,3'-diamino-4,4'-dicarboxydiphenylmethane and 3,3'-dicarboxy-4,4'-diaminodiphenylmethane; and carboxydiphenyl ether compounds such as 3,3'-diamino-4,4'-dicarboxydiphenyl ether. These can be used alone or in appropriate combination.

[0032] Examples of diamines having an ether bond include polyoxyethylene diamine, polyoxypropylene diamine, and polyoxyalkylene diamines containing oxyalkylene groups with different carbon chain lengths. The molecular weight of the diamine having an ether bond is preferably 200 to 3,000, more preferably 400 to 2,000. Examples of polyoxyalkylene diamines include polyoxyethylene diamines such as Jeffamine ED-600, ED-900, ED-2003, EDR-148, and HK-511, manufactured by Huntsman (USA); polyoxypropylene diamines such as Jeffamine D-230, D-400, D-2000, and D-4000; and polytetramethylene ethylene diamines such as Jeffamine XTJ-542, XTJ533, and XTJ536. 2,2'-bis[4-(4-aminophenoxy)phenyl]propane may also be used as a diamine having an ether bond.

[0033] Other diamines may be used in combination with these diamines. Examples of other diamines that can be used in combination include general-purpose aliphatic diamines and aromatic diamines, which can be used alone or in appropriate combination. Specific examples of other diamines include p-phenylenediamine (PPD), 1,3-diaminobenzene, 2,4-toluenediamine, diamines with one benzene nucleus, diaminodiphenyl ethers such as 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, and 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 1,3-bis(3-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,3-bis[2-(4-aminophenyl)isopropyl]benzene, and 1,4-bis[2-(3-aminophenyl)isopropyl]benzene. aromatic diamines such as 3,3'-bis(3-aminophenoxy)biphenyl, 3,3'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, bis[3-(3-aminophenoxy)phenyl]ether, bis[3-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, and 3,3'-diamino-4,4'-dihydroxydiphenyl sulfone; and aliphatic diamines such as 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, and 1,8-diaminooctane.

[0034] The acid anhydride (a1) used in the synthesis of the polyamide-imide resin includes an acid anhydride having at least three carboxyl groups, two of which are anhydride. Examples of such acid anhydrides include those having at least one of an aromatic ring and an aliphatic ring. Suitable examples of the acid anhydride having an aromatic ring include trimellitic anhydride (benzene-1,2,4-tricarboxylic acid 1,2-anhydride, TMA) and 4,4'-oxydiphthalic anhydride, and suitable examples of the acid anhydride having an aliphatic ring include hydrogenated trimellitic anhydride (cyclohexane-1,2,4-tricarboxylic acid 1,2-anhydride, H-TMA). These acid anhydrides may be used alone or in combination of two or more. Furthermore, carboxylic acid dianhydrides may be used in combination. Examples of the carboxylic acid dianhydride include tetracarboxylic acid anhydrides such as pyromellitic dianhydride and 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride.

[0035] The diisocyanate compound used in the synthesis of the polyamide-imide resin may be, but is not limited to, aromatic diisocyanates and their isomers and polymers, aliphatic diisocyanates, alicyclic diisocyanates and their isomers, or other general-purpose diisocyanates. These diisocyanate compounds may be used alone or in combination.

[0036] As described above, polyamide-imide resins can be obtained by reacting reaction materials containing an imidized product and a diisocyanate compound, and may further contain an acid anhydride (a2) similar to that used to obtain the imidized product. This acid anhydride (a2) may be the same as or different from the acid anhydride (a1) described above. In this case, the content of the acid anhydride (a2) in the reaction materials is not particularly limited.

[0037] For the polyamide-imide resins described above, it is particularly preferable to use a carboxyl group-containing diamine, a diamine having an ether bond, and H-TMA, an alicyclic trimellitic acid, in order to enhance alkali solubility and improve developability. For the same reason, it is also preferable to use an aliphatic diisocyanate compound in the second-stage reaction of such polyamide-imide resins. This effectively incorporates an aliphatic chain or alicyclic structure into the structure, thereby enhancing alkali solubility without significantly degrading properties.

[0038] As the carboxyl group-containing resin having an imide structure and an amide structure, polyamideimide resins having a structure represented by the following general formula (1) and a structure represented by the following general formula (2) can be used. [ka] [ka]

[0039] where X 1 is a residue of an aliphatic diamine (a) derived from a dimer acid having 24 to 48 carbon atoms. 2 is a residue of an aromatic diamine (b) having a carboxyl group. Each Y is independently a cyclohexane ring or an aromatic ring.

[0040] Specifically, examples of polyamide-imide resins having such a structure include those represented by the following general formula (3).

[0041] In the following general formula (3), X's each independently represent a diamine residue, Y's each independently represent an aromatic ring or a cyclohexane ring, Z's represents a residue of a diisocyanate compound, and n's a natural number. [ka]

[0042] As the alkali-soluble resin having an imide ring, one of the above compounds can be used alone, or two or more of them can be used in combination.

[0043] The content of the alkali-soluble resin having an imide ring is preferably 30% by mass or more and 70% by mass or less, more preferably 35% by mass or more and 65% by mass or less, calculated as solid content, relative to the total amount of the resin layer (A). When the content of the alkali-soluble resin having an imide ring is within the above range, it is possible to remove the unexposed area without leaving any residue during development, resulting in good resolution.

[0044] The carboxyl group-containing alkali-soluble resin having an imide ring suitable for use in the present invention preferably has an acid value, calculated on a solid content basis, of 20 mgKOH / g to 200 mgKOH / g, more preferably 60 mgKOH / g to 150 mgKOH / g, to accommodate the development process. An acid value of 20 mgKOH / g or greater enhances solubility in aqueous alkaline solutions, improving developability. Furthermore, the degree of crosslinking with the thermosetting resin after the exposure process is enhanced, resulting in sufficient development contrast. On the other hand, an acid value of 200 mgKOH / g or less facilitates accurate pattern writing, and in particular, suppresses so-called heat fog during the first heating step (PEB (post-exposure bake) step) after the exposure step and before the development step, as described below, thereby increasing the process margin.

[0045] Furthermore, in consideration of the developability and the properties of the cured product, the molecular weight of such an alkali-soluble resin having an imide ring is preferably a weight-average molecular weight Mw of 100,000 or less, more preferably 1,000 to 100,000, and even more preferably 2,000 to 50,000. When the molecular weight is 100,000 or less, the alkali solubility of the unexposed area increases, improving the developability. On the other hand, when the molecular weight is 1,000 or more, sufficient development resistance and cured product properties can be obtained in the exposed area after the exposure step and heating step.

[0046] (Photopolymerization initiator) The photopolymerization initiator used in the resin layer (A) can be any of the following known and commonly used ones. In particular, when used in the heating step (PEB step, first heating step) after the exposure step described below, a photopolymerization initiator that also functions as a photobase generator is suitable. The photopolymerization initiator may be used alone or in combination of two or more. In this heating step, a photopolymerization initiator and a photobase generator may be used in combination.

[0047] A photopolymerization initiator that also functions as a photobase generator is a compound that undergoes a change in molecular structure or molecular cleavage upon irradiation with light such as ultraviolet light or visible light, thereby generating one or more basic substances that can function as a catalyst for the polymerization reaction of a thermosetting resin, as described below. Examples of basic substances include secondary amines and tertiary amines. Examples of such photopolymerization initiators that also function as photobase generators include α-aminoacetophenones, oxime esters, and compounds having a substituent such as an acyloxyimino group, an N-formylated aromatic amino group, an N-acylated aromatic amino group, a nitrobenzyl carbamate group, or an alkoxybenzyl carbamate group. Among these, oxime esters and α-aminoacetophenones are preferred, and oxime esters are more preferred. As α-aminoacetophenones, those having two or more nitrogen atoms are particularly preferred.

[0048] The α-aminoacetophenones may be any compounds that have a benzoin ether bond in the molecule and undergo intramolecular cleavage upon exposure to light to produce a basic substance (amine) that acts as a curing catalyst. Commercially available α-aminoacetophenone photopolymerization initiators include Omnirad 907, 369, 369E, and 379 manufactured by IGM Resins.

[0049] Any oxime ester can be used as long as it generates a basic substance upon irradiation with light. Commercially available oxime ester photopolymerization initiators include Irgacure OXE01 and Irgacure OXE02 manufactured by BASF Japan Ltd., N-1919, ADEKA Arcles NCI-831 and NCI-831E manufactured by ADEKA Corporation, and TR-PBG-304 manufactured by Changzhou Strong Electronic New Materials Co., Ltd.

[0050] The content of the photopolymerization initiator is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 18 parts by mass, and even more preferably 1 to 15 parts by mass, calculated as solid content relative to 100 parts by mass of the alkali-soluble resin having an imide ring. When the content is 0.1 part by mass or more, the photocurability of the resin layer (A) is good and the properties of the cured product, such as chemical resistance, are also good. When the content is 20 parts by mass or less, light absorption at the surface of the resist film (cured product) is good and deep curability is less likely to decrease.

[0051] (thermosetting resin) The thermosetting resin may be any resin that hardens upon heating to exhibit electrical insulation, and may be any resin that reacts with the functional group of the curable resin. Examples of the thermosetting resin include epoxy compounds, oxetane compounds, melamine resins, and silicone resins. In particular, epoxy compounds and oxetane compounds are suitable for use in the present invention, and these may be used in combination.

[0052] The epoxy compound may be a known or commonly used compound having one or more epoxy groups, with compounds having two or more epoxy groups being preferred. Examples include monoepoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, and glycidyl (meth)acrylate; bisphenol A epoxy resins, bisphenol S epoxy resins, bisphenol F epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, alicyclic epoxy resins; trimethylolpropane polyglycidyl ether, phenyl-1,3-diglycidyl ether, biphenyl-4,4'-diglycidyl ether, 1,6-hexanediol diglycidyl ether, diglycidyl ether of ethylene glycol or propylene glycol, sorbitol polyglycidyl ether, tris(2,3-epoxypropyl)isocyanurate, and triglycidyl tris(2-hydroxyethyl)isocyanurate, all of which have two or more epoxy groups per molecule. These compounds may be used alone or in combination depending on the required properties.

[0053] Examples of epoxy resins include bisphenol A type epoxy resins such as jER828, jER834, jER1001, and jER1004 manufactured by Mitsubishi Chemical Corporation; EPICLON 840, 850, 850-S, 1050, and 2055 manufactured by DIC Corporation; Epotohto YD-011, YD-013, YD-127, and YD-128 manufactured by Nippon Steel Chemical & Material Co., Ltd.; DER317, DER331, DER661, and DER664 manufactured by The Dow Chemical Company; and Sumi-Epoxy ESA-011, ESA-014, ELA-115, and ELA-128 manufactured by Sumitomo Chemical Co., Ltd. (all trade names). 152, 165, brominated epoxy resins such as Epotohto YDB-400 and YDB-500 manufactured by Nippon Steel Chemical & Material Co., Ltd., DER542 manufactured by Dow Chemical Company, and Sumi-Epoxy ESB-400 and ESB-700 manufactured by Sumitomo Chemical Co., Ltd. (all trade names); jER152 and jER154 manufactured by Mitsubishi Chemical Corporation, DEN431 and DEN438 manufactured by Dow Chemical Company, and EPICLON manufactured by DIC Corporation. N-730, N-770, N-865, Epotohto YDCN-701, YDCN-704 manufactured by Nippon Steel Chemical & Material Co., Ltd., EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306, NC-3000, NC-3000L manufactured by Nippon Kayaku Co., Ltd., Sumi-Epoxy ESCN-195X, ESCN-220 manufactured by Sumitomo Chemical Co., Ltd., YDCN-700-2, YDCN-700-3, YDCN-700-5, YDCN-700-7, YDCN-700-10, YDCN-704 YDCN-704A manufactured by Nippon Steel Chemical & Material Co., Ltd., and EPICLON manufactured by DIC Corporation Novolac epoxy resins such as N-680, N-690, and N-695 (all trade names); bisphenol F epoxy resins such as EPICLON 830 manufactured by DIC Corporation, jER807 manufactured by Mitsubishi Chemical Corporation, and Epotohto YDF-170, YDF-175, and YDF-2004 manufactured by Nippon Steel Chemical & Material Co., Ltd. (all trade names);Hydrogenated bisphenol A type epoxy resins such as Epotohto ST-2004, ST-2007, and ST-3000 (trade names) manufactured by Nippon Steel Chemical & Material Co., Ltd., and YX8034 manufactured by Mitsubishi Chemical Corporation; glycidylamine type epoxy resins such as jER604 manufactured by Mitsubishi Chemical Corporation, Epotohto YH-434 manufactured by Nippon Steel Chemical & Material Co., Ltd., and Sumi-Epoxy ELM-120 manufactured by Sumitomo Chemical Co., Ltd. (all trade names); hydantoin type epoxy resins; Celoxide 2021 manufactured by Daicel Corporation (some alicyclic epoxy resins such as YL-933 manufactured by Mitsubishi Chemical Corporation and EPPN-501, EPPN-502 manufactured by Nippon Kayaku Co., Ltd. (all trade names); trihydroxyphenylmethane type epoxy resins such as YL-6056, YX-4000, YL-6121 manufactured by Mitsubishi Chemical Corporation (all trade names), bixylenol type or biphenol type epoxy resins or mixtures thereof; EBPS-200 manufactured by Nippon Kayaku Co., Ltd., EPX-30 manufactured by ADEKA Corporation, and EXA-1514 manufactured by DIC Corporation Bisphenol S type epoxy resins such as jER157S (trade name) manufactured by Mitsubishi Chemical Corporation; bisphenol A novolac type epoxy resins such as jERYL-931 (all trade names) manufactured by Mitsubishi Chemical Corporation; tetraphenylolethane type epoxy resins such as TEPIC (all trade names) manufactured by Nissan Chemical Co., Ltd.; diglycidyl phthalate resins such as Blenmer DGT manufactured by NOF Corporation; tetraglycidyl xylenolate resins such as ZX-1063 manufactured by Nippon Steel Chemical & Material Co., Ltd. olefin resins; naphthalene skeleton-containing epoxy resins such as ESN-190 and ESN-360 manufactured by Nippon Steel Chemical & Material Co., Ltd., and HP-4032, EXA-4750, and EXA-4700 manufactured by DIC Corporation; dicyclopentadiene skeleton-containing epoxy resins such as HP-7200 and HP-7200H manufactured by DIC Corporation; glycidyl methacrylate copolymer epoxy resins such as CP-50S and CP-50M manufactured by NOF Corporation; and cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resins;Examples of the epoxy resin include, but are not limited to, CTBN-modified epoxy resins (e.g., YR-102 and YR-450 manufactured by Nippon Steel Chemical & Material Co., Ltd.). These epoxy resins may be used alone or in combination of two or more.

[0054] Specific examples of oxetane compounds include 3-ethyl-3-hydroxymethyloxetane (OXT-101 manufactured by Toagosei Co., Ltd.), 3-ethyl-3-(phenoxymethyl)oxetane (OXT-211 manufactured by Toagosei Co., Ltd.), 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane (OXT-212 manufactured by Toagosei Co., Ltd.), 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene (OXT-121 manufactured by Toagosei Co., Ltd.), and bis(3-ethyl-3-oxetanylmethyl)ether (OXT-221 manufactured by Toagosei Co., Ltd.). Further examples include phenol novolac-type oxetane compounds. These oxetane compounds may be used in combination with the epoxy compounds described above, or may be used alone.

[0055] The content of the thermosetting resin is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 45% by mass or less, calculated as solid content, relative to the total amount of the resin layer (A). If the content of the thermosetting resin is within the above range, a crosslinked body is appropriately formed after the thermosetting reaction, resulting in good heat resistance, such as solder heat resistance and high-temperature storage resistance.

[0056] The content of the thermosetting resin is such that the equivalent ratio of the functional group of the alkali-soluble resin (alkali-soluble group such as a carboxyl group) to the functional group of the thermosetting resin that can react with this functional group (thermosetting group such as an epoxy group) is preferably 1:0.1 to 1:10, more preferably 1:0.2 to 1:5, and even more preferably 1:0.5 to 1:2.5, calculated on solid content. With such an equivalent ratio, the functional group of the alkali-soluble resin reacts with the functional group of the thermosetting resin in the exposure step and PEB step, allowing for the formation of a fine cured product pattern with good developability.

[0057] [Other added ingredients] The resin layer (A) contains an alkali-soluble resin having an imide ring, a photopolymerization initiator, and a thermosetting resin. It may further contain other curing components and additives commonly known in the field of electronic materials. Examples of other curing components include cyanate ester resins, active ester resins, maleimide compounds, and alicyclic olefin polymers. Examples of other additives include colorants, organic solvents, non-silicone release agents, photobase generators, thermosetting catalysts, thermal polymerization inhibitors, UV absorbers, silane coupling agents, plasticizers, flame retardants, antistatic agents, antioxidants, antibacterial and antifungal agents, defoamers, leveling agents, thickeners, adhesion promoters, thixotropy promoters, photoinitiator assistants, sensitizers, thermoplastic resins, organic fillers, release agents, surface treatment agents, dispersants, dispersion assistants, surface modifiers, stabilizers, and phosphors.

[0058] (coloring agent) As the colorant, known colorants such as red, blue, green, yellow, and black can be used, and any of pigments, dyes, and coloring matters may be used. However, from the viewpoint of reducing the environmental load and having little effect on the human body, it is preferable that the colorant does not contain halogen.

[0059] Red colorants include monoazos, disazos, azolakes, benzimidazolones, perylenes, diketopyrrolopyrroles, condensed azos, anthraquinones, and quinacridones, and specific examples thereof include those having the following Color Index (CI; published by The Society of Dyers and Colorists) numbers: Monoazo red colorants include Pigment Red 1, 2, 3, 4, 5, 6, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 112, 114, 146, 147, 151, 170, 184, 187, 188, 193, 210, 245, 253, 258, 266, 267, 268, and 269. Examples of disazo red colorants include Pigment Red 37, 38, and 41. Examples of monoazo lake red colorants include Pigment Red 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 50:1, 52:1, 52:2, 53:1, 53:2, 57:1, 58:4, 63:1, 63:2, 64:1, and 68. Examples of benzimidazolone red colorants include Pigment Red 171, 175, 176, 185, and 208. Examples of perylene red colorants include Solvent Red 135, 179, Pigment Red 123, 149, 166, 178, 179, 190, 194, and 224. Examples of diketopyrrolopyrrole red colorants include Pigment Red 254, 255, 264, 270, and 272. Examples of condensed azo red colorants include Pigment Red 220, 144, 166, 214, 220, 221, and 242. Examples of anthraquinone red colorants include Pigment Red 168, 177, and 216, Solvent Red 52, 149, 150, and 207. Examples of quinacridone red colorants include Pigment Red 122, 202, 206, 207, and 209.

[0060] Blue colorants include phthalocyanine and anthraquinone types, and pigment types include compounds classified as pigments, such as Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, and 60. Dye types include Solvent Blue 35, 63, 67, 68, 70, 83, 87, 94, 97, 122, and 136. In addition to the above, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

[0061] Yellow colorants include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone colorants. For example, anthraquinone yellow colorants include Solvent Yellow 163, Pigment Yellow 24, 108, 193, 147, 199, and 202. Isoindolinone yellow colorants include Pigment Yellow 110, 109, 139, 179, and 185. Condensed azo yellow colorants include Pigment Yellow 93, 94, 95, 128, 155, 166, and 180. Benzimidazolone yellow colorants include Pigment Yellow 120, 151, 154, 156, 175, and 181. Examples of monoazo yellow colorants include Pigment Yellow 1, 2, 3, 4, 5, 6, 9, 10, 12, 61, 62, 62:1, 65, 73, 74, 75, 97, 100, 104, 105, 111, 116, 167, 168, 169, 182, and 183. Examples of disazo yellow colorants include Pigment Yellow 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152, 170, 172, 174, 176, 188, and 198.

[0062] Examples of black colorants include carbon black and Pigment Black 1, 6, 7, 8, 9, 10, 11, 12, 13, 18, 20, 25, 26, 28, 29, 30, 31, and 32.

[0063] Other colorants such as purple, orange, brown, and white may also be added. Specific examples include Pigment Violet 19, 23, 29, 32, 36, 38, and 42, Solvent Violet 13 and 36, CI Pigment Orange 1, 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46, 49, 51, 61, 63, 64, 71, and 73, Pigment Brown 23 and 25, and titanium oxide.

[0064] The content of the colorant is not particularly limited, but is preferably 0.1 to 10 parts by mass in terms of solid content relative to 100 parts by mass of the alkali-soluble resin.

[0065] [Organic solvents] The resin composition (A1) for forming the resin layer (A) may contain an organic solvent to adjust the viscosity when a dried coating film described below is obtained. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. These organic solvents can be used alone or in combination of two or more.

[0066] [Resin layer (B)] The melt viscosity of the resin layer (B) at 50°C is 1000 Pa·s or more and 50000 Pa·s or less, preferably 3000 Pa·s or more and 40000 Pa·s or less, more preferably 5000 Pa·s or more and 30000 Pa·s or less, and even more preferably 10000 Pa·s or more and 25000 Pa·s or less. The melt viscosity of the resin layer (B) at 100°C is 50 Pa·s or more and 2000 Pa·s or less, preferably 100 Pa·s or more and 1700 Pa·s or less, more preferably 200 Pa·s or more and 1600 Pa·s or less, and even more preferably 220 Pa·s or more and 1500 Pa·s or less. When the melt viscosity of the resin layer (B) at 50°C and 100°C is within the above range, excessive outflow of the resin layer (B) can be suppressed, and the lamination property and edge covering property become good. In the present invention, the melt viscosity of the resin layer (B) at 50° C. and 100° C. is a value measured by a dynamic viscoelasticity measuring device, which is a rotational rheometer.

[0067] The ratio of the melt viscosity of the resin layer (B) at 50°C to the melt viscosity at 100°C (melt viscosity at 50°C (Pa·s) / melt viscosity at 100°C (Pa·s)) is preferably 10 or more and 100 or less, more preferably 15 or more and 90 or less. When the ratio of the melt viscosity of the resin layer (B) at 50° C. to the melt viscosity at 100° C. is within the above range, the change in melt viscosity due to temperature can be suppressed, and the lamination property and edge covering property become good.

[0068] The resin layer (B) contains an alkali-soluble resin having no imide ring, a polyfunctional photopolymerizable monomer, inorganic particles, and a thermosetting resin, and may further contain other additive components such as a photopolymerization initiator. In the present invention, the melt viscosity of the resin layer (B) at 50°C and 100°C can be adjusted to the above-mentioned preferred range by adjusting the type and content of each component contained in the resin layer (B). The resin layer (B) is formed by applying and drying a resin composition (B1) containing an alkali-soluble resin having no imide ring, a polyfunctional photopolymerizable monomer, inorganic particles, and a thermosetting resin onto the resin layer (A). Each component of the resin layer (B) will be described in detail below.

[0069] (alkali-soluble resin without imide ring) The alkali-soluble resin without an imide ring does not have an imide ring and has an alkali-soluble group that is soluble in an alkaline aqueous solution. The alkali-soluble group is, for example, any one of a phenolic hydroxyl group, a thiol group, and a carboxyl group. Examples of the alkali-soluble resin include a compound having two or more phenolic hydroxyl groups, a carboxyl group-containing resin, a compound having a phenolic hydroxyl group and a carboxyl group, and a compound having two or more thiol groups.

[0070] When the alkali-soluble resin having no imide ring is a carboxyl group-containing resin or a phenol resin, adhesion to the base is improved. In particular, when the alkali-soluble resin having no imide ring is a carboxyl group-containing resin, developability is excellent. The carboxyl group-containing resin is preferably a carboxyl group-containing photosensitive resin having an ethylenically unsaturated group, but may also be a carboxyl group-containing resin having no ethylenically unsaturated group.

[0071] Specific examples of the carboxyl group-containing resin include the compounds (which may be either oligomers or polymers) listed below. (1) Carboxyl group-containing resins obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with unsaturated group-containing compounds such as styrene, α-methylstyrene, lower alkyl (meth)acrylates, and isobutylene. (2) Carboxylic acid-containing urethane resins obtained by the polyaddition reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with carboxyl-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, and diol compounds such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A alkylene oxide adduct diols, and compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups. (3) Terminal carboxyl group-containing urethane resins obtained by reacting acid anhydrides with the terminals of urethane resins obtained by polyaddition reaction of diisocyanate compounds such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with diol compounds such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A alkylene oxide adduct diols, and compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups. (4) Carboxylic acid group-containing urethane resins obtained by the polyaddition reaction of diisocyanates with (meth)acrylates of bifunctional epoxy resins such as bisphenol A epoxy resins, hydrogenated bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bixylenol epoxy resins, and biphenol epoxy resins, or their partially acid anhydride-modified products, carboxylic acid group-containing dialcohol compounds, and diol compounds. (5) A carboxyl group-containing urethane resin that is (meth)acrylated at the terminal by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as hydroxyalkyl (meth)acrylate, during the synthesis of the resin (2) or (4) above. (6) A carboxyl group-containing urethane resin that is (meth)acrylated at the terminal by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate, during the synthesis of the resin (2) or (4) above. (7) A carboxyl group-containing resin (acid-modified epoxy acrylate resin) obtained by reacting a multifunctional epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl groups present in the side chain. (8) A carboxyl group-containing resin (acid-modified epoxy acrylate resin) in which the hydroxyl groups of a bifunctional epoxy resin are further epoxidized with epichlorohydrin, and then (meth)acrylic acid is reacted with the polyfunctional epoxy resin, and a dibasic acid anhydride is added to the resulting hydroxyl groups. (9) A carboxyl group-containing polyester resin obtained by reacting a polyfunctional oxetane resin with a dicarboxylic acid and adding a dibasic acid anhydride to the resulting primary hydroxyl group. (10) A carboxyl group-containing resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide, reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride. (11) A carboxyl group-containing resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate, reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride. (12) A carboxyl group-containing resin obtained by reacting an epoxy compound having multiple epoxy groups in one molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenethyl alcohol, and an unsaturated group-containing monocarboxylic acid, such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl groups of the resulting reaction product with a polybasic acid anhydride, such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, or adipic anhydride. (13) A carboxyl group-containing resin obtained by further adding a compound having one epoxy group and one or more (meth)acryloyl groups in the molecule, such as glycidyl (meth)acrylate, α-methylglycidyl (meth)acrylate, etc., to the carboxyl group-containing resin described in (1) to (12) above.

[0072] Examples of compounds having a phenolic hydroxyl group include compounds having a biphenyl skeleton, a phenylene skeleton, or both of these skeletons, and phenolic resins having various skeletons synthesized using phenol, orthocresol, para-cresol, meta-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, catechol, resorcinol, hydroquinone, methylhydroquinone, 2,6-dimethylhydroquinone, trimethylhydroquinone, pyrogallol, phloroglucinol, etc. Examples of the compound having a phenolic hydroxyl group include known and commonly used phenolic resins such as phenol novolac resin, alkylphenol volac resin, bisphenol A novolac resin, dicyclopentadiene-type phenolic resin, Xylok-type phenolic resin, terpene-modified phenolic resin, polyvinylphenols, bisphenol F, bisphenol S-type phenolic resin, poly-p-hydroxystyrene, condensates of naphthol and aldehydes, and condensates of dihydroxynaphthalene and aldehydes.

[0073] As the alkali-soluble resin not having an imide ring, the above compounds can be used alone or in combination of two or more.

[0074] In this specification, (meth)acrylate is a general term for acrylate, methacrylate and mixtures thereof, and the same applies to other similar expressions.

[0075] The content of the alkali-soluble resin having no imide ring is preferably 15% by mass or more and 70% by mass or less, more preferably 20% by mass or more and 65% by mass or less, and even more preferably 20% by mass or more and 60% by mass or less, in terms of solid content, relative to the total amount of the resin layer (B). When the content of the alkali-soluble resin having no imide ring is within the above range, it is possible to remove the unexposed area without leaving any residue during development, resulting in good resolution.

[0076] The acid value of the alkali-soluble resin having no imide ring is preferably 40 mgKOH / g or more and 200 mgKOH / g or less, more preferably 45 mgKOH / g or more and 120 mgKOH / g or less, calculated as solid content. When the acid value of the alkali-soluble resin having no imide ring is 40 mgKOH / g or more, development with an aqueous alkaline solution becomes easy, and when it is 200 mgKOH / g or less, drawing of a normal cured product pattern becomes easy.

[0077] The weight-average molecular weight of the alkali-soluble resin without an imide ring varies depending on the resin skeleton, but is preferably 1,500 to 150,000, more preferably 1,500 to 100,000. When the weight-average molecular weight is 1,500 or more, the tack-free performance is good, the moisture resistance of the coating film after exposure is good, film loss during development is suppressed, and a decrease in resolution can be suppressed. On the other hand, when the weight-average molecular weight is 150,000 or less, the developability is good and storage stability is also excellent.

[0078] (Multifunctional photopolymerizable monomer) The polyfunctional photopolymerizable monomer is a monomer having two or more ethylenically unsaturated groups in one molecule, and a photopolymerizable oligomer, a photopolymerizable vinyl monomer, or the like, which is a known and commonly used photocurable monomer, can be used. The polyfunctional photopolymerizable monomer can be used alone or in combination of two or more types depending on the required properties. The polyfunctional photopolymerizable monomer can also be used as a reactive diluent.

[0079] Examples of photopolymerizable oligomers include unsaturated polyester oligomers and (meth)acrylate oligomers. Examples of (meth)acrylate oligomers include epoxy (meth)acrylates such as phenol novolac epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, and bisphenol-type epoxy (meth)acrylate, as well as urethane (meth)acrylate, epoxy urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, and polybutadiene-modified (meth)acrylate, as well as alkylene oxide-modified, caprolactone-modified, and other derivatives thereof. In this specification, the term "(meth)acrylate" collectively refers to acrylate, methacrylate, and mixtures thereof, and the same applies to other similar expressions.

[0080] Examples of the photopolymerizable vinyl monomer include known and commonly used ones, such as polyfunctional allyl compounds such as triallyl isocyanurate, diallyl phthalate, and diallyl isophthalate; alkylene polyol poly(meth)acrylates such as ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; diethylene glycol di(meth)acrylate, dipentaerythritol hexa(meth)acrylate; Examples of the alkylene oxide-modified poly(meth)acrylate include polyoxyalkylene glycol poly(meth)acrylates such as triethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, ethoxylated trimethylolpropane triacrylate, and propoxylated trimethylolpropane tri(meth)acrylate; poly(meth)acrylates such as hydroxypivalic acid neopentyl glycol ester di(meth)acrylate; isocyanurate-type poly(meth)acrylates such as tris[(meth)acryloxyethyl]isocyanurate; and alkylene oxide-modified, caprolactone-modified, or other derivatives thereof. In particular, the alkylene oxide-modified poly(meth)acrylate is preferably ethylene oxide-modified or propylene oxide-modified, and more preferably ethylene oxide-modified.

[0081] The functionality of the polyfunctional photopolymerizable monomer in the present invention is 2 or more, preferably 3 or more. When the functionality of the polyfunctional photopolymerizable monomer is within the above-mentioned range, curing of the exposed area proceeds sufficiently, and sufficient development resistance is exhibited during development, resulting in good resolution.

[0082] The content of the polyfunctional photopolymerizable monomer is preferably 1 part by mass or more and 50 parts by mass or less, more preferably 5 parts by mass or more and 45 parts by mass or less, and even more preferably 10 parts by mass or more and 40 parts by mass or less, in terms of solid content relative to 100 parts by mass of the alkali-soluble resin. If the content of the polyfunctional photopolymerizable monomer is within the above-mentioned range, curing of the exposed area proceeds sufficiently and sufficient development resistance is exhibited during development, resulting in good resolution.

[0083] (Inorganic particles) The laminated structure of the present invention contains various inorganic particles in the resin layer (B) in order to improve the drying properties of the dry film, lamination properties to a substrate, edge covering properties, and to impart or improve other functions. The inorganic particles contained in the resin layer (B) may or may not be in the form of a powder (an aggregate of fine solid particles). Examples of inorganic particles include inorganic fillers that function as a bulking agent and the flame retardants described below.

[0084] ((Flame retardant)) For example, flame retardants, which are one type of inorganic particles, can be used. These inorganic particles undergo endothermic dehydration reactions and contain a large amount of water, such as metal hydroxides such as aluminum hydroxide and magnesium hydroxide, and layered double hydroxides such as hydrotalcite and hydrotalcite-like compounds. Other flame retardants that can be used include phosphate esters and condensed phosphate esters, phosphorus-containing (meth)acrylates, phosphorus-containing compounds with phenolic hydroxyl groups, cyclic phosphazene compounds, phosphazene oligomers, and metal phosphinates. Antimony compounds such as antimony trioxide and antimony pentoxide, and halides such as pentabromodiphenyl ether and octabromodiphenyl ether. These compounds provide flame retardancy by forming a carbonized layer on the resin surface during combustion, thereby blocking oxygen and heat from the combustion product and / or by trapping radicals generated during combustion to stop the chain reaction.

[0085] ((Inorganic filler)) As the inorganic filler, conventionally known inorganic particles other than the above-mentioned flame retardants can be used, such as silica, crystalline silica, Neuburg silica, glass powder, talc, clay, magnesium carbonate, calcium carbonate, natural mica, synthetic mica, barium sulfate, barium titanate, iron oxide, non-fibrous glass, mineral wool, aluminum silicate, calcium silicate, zinc oxide, etc.

[0086] The inorganic filler may be surface-treated to enhance dispersibility in the resin layer (B). The use of a surface-treated inorganic filler can suppress aggregation. The surface treatment method is not particularly limited, and any known or commonly used method may be used. However, it is preferable to treat the surface of the inorganic filler with a surface treatment agent having a curable reactive group, such as a coupling agent having a curable reactive group as an organic group.

[0087] Examples of coupling agents that can be used include silane-based, titanate-based, aluminate-based, and zircoaluminate-based coupling agents. Among these, silane-based coupling agents are preferred. Examples of such silane-based coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N-(2-aminomethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane. These can be used alone or in combination. It is preferred that these silane-based coupling agents are immobilized on the surface of the inorganic filler in advance by adsorption or reaction. Here, the amount of the coupling agent to be treated with respect to 100 parts by mass of the inorganic filler is preferably 0.5 to 10 parts by mass.

[0088] The content of the inorganic filler, calculated as solid content, relative to the total amount of the resin layer (B), is preferably 10% by mass to 80% by mass, more preferably 13% by mass to 70% by mass, and even more preferably 15% by mass to 60% by mass. When the content of the inorganic filler is within the above range, thermal properties such as solder heat resistance and high-temperature storage resistance are improved. Furthermore, when a typical dry film is thickened, the resin tends to flow during lamination, resulting in reduced edge covering. However, by adding an inorganic filler, excessive flow can be suppressed. Furthermore, when a typical dry film is thickened, the dry film becomes difficult to dry. However, by adding an inorganic filler, the drying property is improved, making it easier to peel off the second film during lamination.

[0089] The average particle size of the inorganic filler is preferably 0.02 μm or more and 10 μm or less, more preferably 0.05 μm or more and 5 μm or less, and even more preferably 0.1 μm or more and 3 μm or less. If the average particle size of the inorganic filler is within the above numerical range, the dispersibility of the inorganic filler will be good. The average particle size refers to the particle size at 50% cumulative volume obtained using a laser diffraction / scattering particle size distribution measurement method. The average particle size of the inorganic filler refers to the value measured as described above for the inorganic filler before preparing (stirring and kneading) the resin composition.

[0090] (thermosetting resin) The thermosetting resin contained in the resin layer (B) may be the same as the thermosetting resin contained in the resin layer (A).

[0091] The content of the thermosetting resin is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 45% by mass or less, calculated as solid content, relative to the total amount of the resin layer (B). If the content of the thermosetting resin is within the above range, a crosslinked body is appropriately formed after the thermosetting reaction, resulting in good heat resistance, such as solder heat resistance and high-temperature storage resistance.

[0092] [Other added ingredients] The resin layer (B) contains an alkali-soluble resin without an imide ring, a polyfunctional photopolymerizable monomer, inorganic particles, and a thermosetting resin. It may also contain other commonly used curing components and additives, such as photopolymerization initiators, commonly used in the field of electronic materials. Examples of other curing components include cyanate ester resins, active ester resins, maleimide compounds, and alicyclic olefin polymers. Examples of other additives include non-silicone release agents, photobase generators, thermosetting catalysts, colorants, thermal polymerization inhibitors, UV absorbers, silane coupling agents, plasticizers, antistatic agents, antioxidants, antibacterial and antifungal agents, defoamers, leveling agents, thickeners, adhesion promoters, thixotropy promoters, photoinitiator assistants, sensitizers, thermoplastic resins, organic fillers, release agents, surface treatment agents, dispersants, dispersion assistants, surface modifiers, stabilizers, and phosphors.

[0093] (Photopolymerization initiator) The resin layer (B) may contain a photopolymerization initiator. Any photopolymerization initiator known as a photopolymerization initiator or a photoradical generator can be used as the photopolymerization initiator.

[0094] Examples of the photopolymerization initiator include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, and bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylphenylphosphine oxide. Bisacylphosphine oxides such as 2,6-dimethoxybenzoyldiphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, and bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, and 2-methylbenzoyldiphenylphosphine oxide. monoacylphosphine oxides such as 1-hydroxy-cyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-hydroxy-2-methyl- Hydroxyacetophenones such as methyl-1-phenylpropan-1-one; benzoins such as benzoin, benzil, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether; benzoin alkyl ethers; benzophenones such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bisdiethylaminobenzophenone;Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4- Acetophenones such as [(4-morpholinyl)phenyl]-1-butanone and N,N-dimethylaminoacetophenone; thioxanthones such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone; anthraquinones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; ethyl- Benzoic acid esters such as 4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and p-dimethylbenzoic acid ethyl ester; oxime esters such as 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime); titanocenes such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium and bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyr-1-yl)ethyl)phenyl]titanium;Examples of suitable photopolymerization initiators include phenyl disulfide, 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide. One photopolymerization initiator may be used alone, or two or more may be used in combination. Among these, monoacylphosphine oxides and oxime esters are preferred, with 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, and 1-(O-acetyloxime) being more preferred.

[0095] The content of the photopolymerization initiator is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 18 parts by mass, and even more preferably 1 to 15 parts by mass, calculated as solid content relative to 100 parts by mass of the alkali-soluble resin. When the content is 0.1 part by mass or more, the photocurability of the resin layer (B) is good and the properties of the cured product, such as chemical resistance, are also good. When the content is 20 parts by mass or less, light absorption at the surface of the resist film (cured product) is good and deep curing is less likely to decrease.

[0096] A photoinitiator assistant or sensitizer may be used in combination with the above-mentioned photopolymerization initiator. As the photoinitiator assistant or sensitizer, the same photoinitiator assistant or sensitizer as the photoinitiator assistant or sensitizer contained in the resin layer (A) may be used. Furthermore, one type of photoinitiator assistant or sensitizer may be used alone, or two or more types may be used in combination.

[0097] [Organic solvents] The resin composition (B1) for forming the resin layer (B) may contain an organic solvent to adjust the viscosity when a dried coating film described below is obtained. The organic solvent may be the same as the organic solvent used when forming the resin layer (A).

[0098] (First film) The first film supports the resin layer (i.e., a dried coating film made of a resin composition) and adheres to the resin layer when the laminate structure is integrally molded by laminating it onto a substrate by heating or the like so that the resin layer side of the laminate structure is in contact with the substrate. The first film may be peeled off from the laminate structure in a step after lamination. In the present invention, it is preferable that the first film is peeled off from the laminate structure after the first heating described below.

[0099] The first film can be any film without particular limitation, and examples of films that can be preferably used include polyester films such as polyethylene terephthalate and polyethylene naphthalate, and films made of thermoplastic resins such as polyimide films, polyamideimide films, polypropylene films, and polystyrene films, but among these, polyester films are preferably used from the viewpoints of optical properties, heat resistance, mechanical strength, handleability, etc. The first film may be a single layer, or may be a laminate of two or more layers.

[0100] Furthermore, it is preferable to use the above-mentioned thermoplastic resin film which has been oriented uniaxially or biaxially in order to improve its strength.

[0101] The thickness of the first film is not particularly limited, but may be appropriately selected depending on the application within the range of, for example, 10 to 150 μm.

[0102] (Second film) The laminate structure according to the present invention has a second film on the other side of the resin layer (the side opposite to the first film) for the purposes of preventing dust and the like from adhering to the surface of the resin layer and improving handleability. The second film is peeled off from the laminate structure before lamination when the laminate structure is integrally molded by laminating it onto a substrate by heating or the like so that the resin layer side of the laminate structure is in contact with the substrate.

[0103] The surface of the second film that comes into contact with the resin layer may be subjected to a release treatment, for example, by applying a coating liquid prepared by dissolving or dispersing a release agent such as waxes, silicone wax, alkyd resins, urethane resins, melamine resins, or silicone resins in an appropriate solvent to the surface of the second film by a known method such as a coating method such as roll coating or spray coating, gravure printing, or screen printing, and drying the coating liquid.

[0104] As the second film, for example, a film made of the above-mentioned thermoplastic resin can be suitably used, as in the first film. In addition, in order to make it easier to peel off the second film when using the laminated structure, the surface of the second film that comes into contact with the resin layer may be subjected to the above-mentioned release treatment.

[0105] The thickness of the second film is not particularly limited, but may be appropriately selected depending on the application within the range of, for example, 10 to 150 μm.

[0106] [Method for forming laminated structure] When forming the laminate structure, first, the resin composition (A1) for forming the resin layer (A) is applied to a first film in a uniform thickness using a comma coater, blade coater, or the like. The applied resin composition (A1) is then dried, typically at a temperature of 40 to 130°C for 1 to 30 minutes, to form the resin layer (A). Then, the resin composition (B1) for forming the resin layer (B) is applied to a uniform thickness using a comma coater, blade coater, or the like on the surface of the resin layer (A) opposite the first film. The applied resin composition (B1) is then dried, typically at a temperature of 40 to 130°C for 1 to 30 minutes, to form the resin layer (B). A second film is laminated to the surface of the resin layer (B) opposite the resin layer (A), to form the laminate structure. Alternatively, the resin layer (B) and the resin layer (A) may be formed on the second film, and then the first film may be laminated thereon. When the laminate structure is long, it may be wound into a roll to form a rolled laminate structure. The rolled laminated structure may be cut to a predetermined width as needed.

[0107] [Cured resin layer] The cured product of the present invention can be obtained by curing the resin layer (A) and the resin layer (B). For example, as in the method for forming a cured product of the present invention, the cured product can be obtained by peeling off the second film of the laminate structure (i.e., in the state of the resin layer (A), the resin layer (B), and the first film), sequentially performing exposure and first heating (post-exposure baking), and then peeling off the first film (i.e., in the state of the resin layer (A) and the resin layer (B) being exposed), sequentially performing development and second heating (thermal curing reaction of the carboxyl group and the epoxy group). The resulting cured product is particularly suitable as a coverlay or solder resist (insulating cured film) for flexible printed wiring boards.

[0108] [Electronic component having a cured resin layer] The present invention also provides electronic components having a cured resin layer. In the present invention, electronic components refer to components used in electronic circuits, including active components such as printed wiring boards, particularly flexible printed wiring boards, transistors, light-emitting diodes, and laser diodes, as well as passive components such as resistors, capacitors, inductors, and connectors. Due to its excellent lamination and edge covering properties, the cured resin layer of the present invention can be suitably used as an insulating cured film for various wiring boards. Therefore, the laminated structure of the present invention and its cured product can also be used for wiring boards with a high copper thickness, for example, wiring boards with a wiring thickness of preferably 210 μm (6 oz) or 140 μm (4 oz). The cured resin layer of the present invention is suitable as an insulating cured film for these electronic components.

[0109] [Method for forming a cured product] The cured product of the present invention can be obtained by curing the resin layer (dried coating film of the resin composition) of the above-mentioned laminate structure. A method for forming a cured product and a method for forming the above-mentioned cured product (cured coating film) on a substrate on which a circuit pattern has been formed include the following steps: a step of peeling off the second film from the laminate structure to expose the resin layer, and bonding the resin layer (B) of the laminate structure onto a substrate on which the circuit pattern has been formed, thereby arranging the first film and the resin layer on the substrate; an exposure step of irradiating a predetermined portion of the laminated structure with active energy rays through the first film; a first heating step of heating the resin layer after the exposure step; a development step of peeling off the first film from the resin layer after the first heating step and removing a region of the resin layer after the exposure step that has not been irradiated with active energy rays; and a second heating step of heating the resin layer after the developing step; Each step will be described below.

[0110] (A process of laminating a resin layer onto a substrate on which a circuit pattern has been formed) First, the second film is peeled off from the laminate structure to expose the resin layer, and the resin layer of the laminate structure is laminated onto a substrate on which a circuit pattern is formed. Examples of substrates on which a circuit pattern is formed include printed wiring boards and flexible printed wiring boards with pre-formed circuits, as well as copper-clad laminates of all grades (e.g., FR-4) made of materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, copper-clad laminates for high-frequency circuits made of fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate ester, etc., as well as polyimide films, PET films, glass substrates, ceramic substrates, wafer plates, etc.

[0111] As a method for disposing the resin layer of the laminated structure on the circuit board, both a conveyor type laminator and a vacuum roll laminator can be used.

[0112] A vacuum roll laminator is a device that continuously laminates a laminate structure onto a substrate in a vacuum. By using a vacuum roll laminator, it is possible to laminate a laminate structure onto an uneven substrate without introducing air bubbles or dust. Furthermore, laminating in a vacuum also eliminates contamination. Using a vacuum roll laminator makes it possible to manufacture long substrates.

[0113] The conditions for the vacuum roll laminator can be appropriately adjusted depending on the thickness of the entire resin layer of the laminated structure and the melt viscosity of the resin layer (A) and the resin layer (B) at 50° C. and 100° C. For example, the conditions for the vacuum roll laminator are a temperature of 80 to 90° C. and a pressure of 3 to 5 kgf / cm. 2 The reduced pressure condition is preferably 10 to 100 Pa.

[0114] A conveyor laminator is a laminator device that is based on single-substrate processing. It bonds a laminated structure to a substrate that fits inside a vacuum chamber, removes air bubbles using a vacuum, and then bonds the laminated structure to an uneven substrate without introducing air bubbles by applying pressure.

[0115] The conditions for the conveying type laminator can be appropriately adjusted depending on the thickness of the entire resin layer of the laminated structure and the melt viscosities of the resin layer (A) and the resin layer (B) at 50° C. and 100° C. For example, the conditions for the conveying type laminator are preferably a temperature of 50° C. to 80° C., a vacuum time of 10 to 60 seconds, and a pressure time of 20 to 120 seconds.

[0116] (Exposure process) Next, predetermined portions of the laminate structure are exposed to light (irradiated with active energy rays) through the first film. This process cures only the exposed resin layer. The exposure process is not particularly limited, and may involve, for example, selective exposure to active energy rays through a photomask on which a desired pattern is formed using a contact (or non-contact) method, or exposure of the desired pattern to active energy rays using a direct imaging device.

[0117] The exposure device used for actinic energy ray irradiation may be a device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, or the like, and capable of irradiating ultraviolet light in the range of 350 to 450 nm. Furthermore, a direct imaging device (e.g., a laser direct imaging device that directly draws an image with a laser based on CAD data from a computer) can also be used. The laser light source for the direct imaging device may be either a gas laser or a solid-state laser, as long as it uses laser light with a maximum wavelength in the range of 350 to 410 nm. The exposure dose for image formation varies depending on factors such as the film thickness, but is generally 20 to 800 mJ / cm. 2 , preferably 20 to 600 mJ / cm 2 The range may be:

[0118] (First heating step) After the exposure, the resin layer is cured by first heating. This process, known as post-exposure baking (PEB), suppresses cure shrinkage of the laminate after photolithography, imparts development resistance during development, and provides the cured laminate with excellent resolution. When the resin layer (A) and the resin layer (B) contain a photopolymerization initiator that functions as a photobase generator, or both a photopolymerization initiator and a photobase generator, the base generated in the exposure process can cure the resin layer (A) and the resin layer (B) to their depths. The heating temperature is preferably a temperature that thermally cures the irradiated portion of the resin layer but not the non-irradiated portion. For example, it is 40 to 140°C, preferably 60 to 120°C. The heating time is, for example, 1 to 120 minutes, preferably 10 to 80 minutes. Known heating means, such as a hot air oven, an electric oven, or an infrared induction heating oven, can be used. In the PEB process, curing proceeds mainly through a thermal ring-opening reaction of epoxy resins, etc., which means that distortion and cure shrinkage can be reduced compared to when curing is carried out through a photoradical reaction in an exposure process.In addition, in non-irradiated areas, no base is generated from the photopolymerization initiator, so the thermal curing reaction is suppressed.

[0119] (Developing process) After the exposure step and the first heating step, the first film is peeled off from the laminated structure, and the region of the resin layer that has not been irradiated with the active energy rays after the exposure step is removed (this step is called development), thereby forming a patterned resin layer on the substrate.

[0120] The developing step is not particularly limited, and may be a dipping method, a shower method, a spray method, a brush method, etc. As the developer, an aqueous alkali solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, or an amine may be used.

[0121] (Second heating step) Next, the patterned resin layer is subjected to a second heating step, in which the layer is cured by heat to form a cured product (cured coating). This step, called main curing or additional curing, promotes the polymerization of unreacted monomers in the resin layer. Furthermore, in the case of a carboxyl group-containing alkali-soluble resin, in addition to promoting the polymerization, the amount of remaining carboxyl groups can be reduced by thermally curing the carboxyl groups and epoxy resin. The thermal curing can be carried out at a temperature of 100 to 200°C for approximately 20 to 90 minutes.

[0122] The additional curing may be performed by irradiating active energy rays (light) to form a cured product (cured coating). Similarly, exposure can also promote polymerization of unreacted monomers in the resin layer, and furthermore, thermally cure the carboxyl group-containing photosensitive resin and the epoxy resin, thereby reducing the amount of remaining carboxyl groups. Irradiation with active energy rays can be performed in the same manner as the exposure described above, but is preferably performed under conditions of stronger irradiation energy than that used during exposure. For example, 500 to 3000 mJ / cm 2 The main curing may be carried out by thermal curing after exposure to light. [Example]

[0123] The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples. In the following, "parts" and "%" are all by mass unless otherwise specified.

[0124] [Preparation of Resin Composition (A1) for Forming Resin Layer (A)] (Synthesis of alkali-soluble resins containing imide rings) A separable three-neck flask equipped with a stirrer, nitrogen inlet tube, fractionating ring, and cooling ring was charged with 12.2 g of 3,5-diaminobenzoic acid, 8.2 g of 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 30 g of N-methylpyrrolidone, 30 g of γ-butyrolactone, 27.9 g of 4,4'-oxydiphthalic anhydride, and 3.8 g of trimellitic anhydride, and the mixture was stirred at room temperature and 100 rpm for 4 hours under a nitrogen atmosphere. 20 g of toluene was then added, and the mixture was stirred at 150 rpm in a silicone bath at 180°C for 4 hours while distilling off toluene and water, yielding an alkali-soluble resin solution having imide rings.

[0125] (Preparation of Resin Composition Containing Alkali-Soluble Resin Having Imide Ring: Blending Example 1) 100 parts by mass of the alkali-soluble resin solution having an imide ring obtained by the synthesis above, 63.5 parts by mass of an epoxy resin ("jER828" manufactured by Mitsubishi Chemical Corporation, molecular weight: 370) as a thermally reactive compound, and 10 parts by mass of a photopolymerization initiator ("Irgacure OXE02" manufactured by BASF Japan Ltd.) were blended and premixed with a stirrer, followed by kneading with a three-roll mill to prepare a resin composition (Composition Example 1) containing an alkali-soluble resin having an imide ring. The solids content of the alkali-soluble resin having an imide ring was 37% by mass relative to 100% by mass of the solids content of the resin composition. That is, it was 37% by mass relative to 100% by mass of the solids content of the resin layer (A).

[0126] (Preparation of Resin Compositions Containing Alkali-Soluble Resins Having Imide Rings: Formulation Examples 2 to 6) Resin compositions (A1) for forming the resin layer (A) in the laminate structure were prepared by blending the components shown in Blending Examples 2 to 6 according to Table 1, premixing them in a stirrer, and then kneading them in a three-roll mill. Unless otherwise specified, the values ​​in Table 1 are parts by mass and represent the solid content excluding organic solvents.

[0127] [Table 1]

[0128] Details of each component in Table 1 are as follows: *1: Alkali-soluble resin with imide ring synthesized above *2: Oxime ester photopolymerization initiator, manufactured by BASF Japan Ltd., Irgacure OXE02 *3: Epoxy resin, Mitsubishi Chemical Corporation, jER828 *4: Epoxy resin, manufactured by DIC Corporation, EPICLON N-770 *5: Epoxy resin, manufactured by Printec Co., Ltd., TECHMORE VG3101L *6: Epoxy resin, manufactured by Nippon Steel Chemical & Material Co., Ltd., ZX-1059 *7: Epoxy resin, manufactured by DIC Corporation, EPICLON N-695 *8: Black colorant, manufactured by Ako Kasei Co., Ltd., Tilack D TM-A

[0129] (Measurement of Melt Viscosity of Resin Composition (A1) Used in Resin Layer (A)) Each resin composition obtained above was applied to a fluororesin (AGC Corporation, Aflex 50 HK NT) using an applicator with a 100 μm upper gap height and heated in an oven at 80°C for 30 minutes to produce a dried coating film with a thickness of approximately 50 μm. This dried coating film was then cut to the required size and laminated using a conveyor-type vacuum laminator (Nikko Materials Co., Ltd., CVP-300) under conditions of lamination temperature = 60°C, vacuum time = 20 seconds, and pressure time = 30 seconds. A release paper was placed on the surface of the resin layer to prevent adhesion to the conveyor film. The release paper was then peeled off, and another resin layer was layered and laminated four times. The total thickness of the laminated resin layer was 200 μm. The melt viscosity was measured under the following conditions using an RS-6000 manufactured by Thermo Fisher Scientific Co., Ltd. The melt viscosities at 50°C and 100°C are shown in Table 2. (Melt viscosity measurement conditions) Sensor: Φ20mm parallel plate type Heating rate: 5℃ / min Measurement frequency: 1Hz Measurement pressure: 3Pa

[0130] [Table 2]

[0131] [Preparation of Resin Composition (B1) for Forming Resin Layer (B)] (Synthesis of alkali-soluble urethane resin 1) A 2 L flask equipped with a stirrer and reflux condenser was charged with 378.0 g of bisphenol A epoxy compound ("jER828" manufactured by Mitsubishi Chemical Corporation; bifunctional bisphenol A epoxy resin, epoxy equivalent: 189 g / eq), 142.7 g of acrylic acid (molecular weight: 72.06), 2.94 g of 2,6-di-tert-butyl-p-cresol as a thermal polymerization inhibitor, and 1.53 g of triphenylphosphine as a reaction catalyst. The mixture was reacted at 98 °C until the acid value of the reaction solution reached 0.5 mg KOH / g or less, yielding epoxy acrylate compound (a) (theoretical molecular weight: 510.7). Next, 594.0 g of carbitol acetate as a reaction solvent and 105.5 g of dimethylolpropionic acid (b) (molecular weight: 134.16) were added to the reaction solution, and the temperature was raised to 45 °C. To this solution, 264.7 g of isophorone diisocyanate (c) (molecular weight: 222.28) was gradually added dropwise so that the reaction temperature did not exceed 65° C. After the addition was completed, the temperature was raised to 80° C., and the infrared absorption spectrum was measured. -1 The reaction was continued for 6 hours until absorption by the nearby isocyanate groups ceased, and then for another 2 hours at 98°C. In this way, a resin solution (alkali-soluble urethane resin 1) containing 60% by mass of alkali-soluble urethane resin as a solid content was obtained. The acid value was measured and found to be 28.9 mg KOH / g (solid content acid value: 48.2 mg KOH / g).

[0132] (Synthesis of alkali-soluble urethane resin 2) A reaction vessel equipped with a stirrer, thermometer, and condenser was charged with 3600 g (4.5 mol) of a polycarbonate diol (TJ5650J manufactured by Asahi Kasei Corporation, number average molecular weight 800) derived from 1,5-pentanediol and 1,6-hexanediol as a compound having two or more alcoholic hydroxyl groups, 814 g (5.5 mol) of dimethylol butanoic acid, and 186 g (1.6 mol) of 2-hydroxyethyl acrylate as a molecular weight modifier (reaction terminator). Next, 2009 g (10.8 mol) of trimethylhexamethylene diisocyanate as an isocyanate compound without an aromatic ring was charged, and the mixture was heated to 60 °C with stirring. When the temperature in the reaction vessel began to drop, the mixture was heated again and continued stirring at 80 °C. The absorption spectrum of the isocyanate group (2280 cm) was measured by infrared absorption spectroscopy. -1 The reaction was terminated after confirming that the carboxyl group-containing alkali-soluble urethane resin had disappeared. Carbitol acetate was then added so that the solid content was 60% by mass, yielding a viscous liquid carboxyl group-containing alkali-soluble urethane resin (alkali-soluble urethane resin 2) containing a diluent. The acid value of the solid content of the resulting carboxyl group-containing alkali-soluble urethane resin 2 was 49.8 mgKOH / g.

[0133] (Synthesis of acid-modified epoxy acrylate resin 1) 380 parts of bisphenol F epoxy resin (epoxy equivalent: 950 g / eq, softening point: 85°C) with an average degree of polymerization (n) of 6.2 and 925 parts of epichlorohydrin were dissolved in 462.5 parts of dimethyl sulfoxide, and then 60.9 parts of 98.5% NaOH were added over 100 minutes at 70°C with stirring. The reaction was continued for another 3 hours at 70°C. After the reaction was completed, 250 parts of water were added and the mixture was washed with water. After oil-water separation, most of the dimethyl sulfoxide and excess unreacted epichlorohydrin were recovered from the oil layer by distillation under reduced pressure. The remaining reaction product containing by-product salts and dimethyl sulfoxide was dissolved in 750 parts of methyl isobutyl ketone, and 10 parts of 30% NaOH were added. The mixture was reacted at 70°C for 1 hour. After the reaction was completed, the mixture was washed twice with 200 parts of water. After oil-water separation, methyl isobutyl ketone was recovered by distillation from the oil layer to obtain epoxy resin (a) with an epoxy equivalent of 310 g / eq and a softening point of 69°C. Based on the epoxy equivalent, approximately 5 of the 6.2 alcoholic hydroxyl groups in the starting bisphenol F epoxy resin were epoxidized in the obtained epoxy resin (a). 310 parts of this epoxy resin (a) and 282 parts of carbitol acetate were charged into a flask and heated to 90°C with stirring to dissolve. The resulting solution was cooled to 60°C, and 72 parts (1 mol) of acrylic acid, 0.5 parts of methylhydroquinone, and 2 parts of triphenylphosphine were added. The mixture was heated to 100°C and reacted for approximately 60 hours to obtain a reaction product with an acid value of 0.2 mgKOH / g. To this was added 140 parts (0.92 mol) of tetrahydrophthalic anhydride, and the mixture was heated to 90°C to carry out a reaction, thereby obtaining an acid-modified epoxy acrylate resin (acid-modified epoxy acrylate resin 1). The solid content concentration of the obtained acid-modified epoxy acrylate resin 1 was 62 mass%, and the solid acid value (mgKOH / g) was 100.

[0134] (Synthesis of acid-modified epoxy acrylate resin 2) 220 parts of a cresol novolac epoxy resin (EPICLON N-695 manufactured by DIC Corporation; epoxy equivalent: 220) was placed in a four-neck flask equipped with a stirrer and a reflux condenser, and 214 parts of carbitol acetate was added and dissolved by heating. Next, 0.1 parts of hydroquinone as a polymerization inhibitor and 2.0 parts of dimethylbenzylamine as a reaction catalyst were added. This mixture was heated to 95-105°C, and 72 parts of acrylic acid was slowly added dropwise, allowing the reaction to proceed for 16 hours. The reaction product was cooled to 80-90°C, and 106 parts of tetrahydrophthalic anhydride was added. The reaction was allowed to proceed for 8 hours, cooled, and then discharged. The acid-modified epoxy acrylate resin thus obtained (acid-modified epoxy acrylate resin 2) had a solids content of 65% by mass, an acid value of 100 mgKOH / g of solids, and a weight-average molecular weight (Mw) of approximately 3,500. The weight-average molecular weight was measured by gel permeation chromatography (GPC).

[0135] The components shown in Formulation Examples 7 to 16 were blended according to the formulations shown in Table 3, premixed in a stirrer, and then kneaded in a three-roll mill to prepare resin compositions (B1) for forming the resin layer (B) in the laminate structure. Unless otherwise specified, the values ​​in Table 3 are parts by mass and represent the solid content excluding organic solvents.

[0136] [Table 3]

[0137] Details of each component in Table 3 are as follows: *1: Alkali-soluble urethane resin 1 synthesized above *2: Alkali-soluble urethane resin 2 synthesized above *3: Acid-modified epoxy acrylate resin 1 synthesized above *4: Acid-modified epoxy acrylate resin 2 synthesized above *5: EO-modified (n≒1) trimethylolpropane triacrylate (trifunctional), manufactured by Toagosei Co., Ltd., Aronix M-350 *6: ε-caprolactone-modified dipentaerythritol hexaacrylate (hexafunctional), manufactured by Nippon Kayaku Co., Ltd., KAYARAD DPCA-60 *7: Aromatic urethane acrylate (bifunctional), Daicel Allnex Corporation, RAYLOK 5021 *8: Aluminum hydroxide, manufactured by Resonac Co., Ltd., Hijilite H-42M *9: Silica, manufactured by Admatechs Co., Ltd., ADMAFINE SO-C2 *10: Barium sulfate, manufactured by Sakai Chemical Industry Co., Ltd., B-30 *11: Epoxy resin, manufactured by Nippon Kayaku Co., Ltd., NC-3000L *12: 2,4,6-trimethylbenzoyl-diphenylphosphine oxide

[0138] (Measurement of Melt Viscosity of Resin Composition (B1) Used in Resin Layer (B)) Each resin composition obtained above was applied to a fluororesin (AGC Corporation, Aflex 50 HK NT) using an applicator with a 200 μm upper gap height and heated in an oven at 80°C for 30 minutes to produce a dried coating film with a thickness of approximately 100 μm. This dried coating film was then cut to the required size and laminated using a conveyor-type vacuum laminator (Nikko Materials Co., Ltd., CVP-300) under conditions of lamination temperature = 60°C, vacuum time = 20 seconds, and pressure time = 30 seconds. A release paper was placed on the surface of the resin layer to prevent adhesion to the conveyor film. The release paper was then peeled off, and another resin layer was layered and laminated four times. The total thickness of the laminated resin layer was 400 μm. The melt viscosity was measured under the following conditions using an RS-6000 manufactured by Thermo Fisher Scientific Co., Ltd. The melt viscosities at 50°C and 100°C are shown in Table 4. (Melt viscosity measurement conditions) Sensor: Φ20mm parallel plate type Heating rate: 5℃ / min Measurement frequency: 1Hz Measurement pressure: 3Pa

[0139] [Table 4]

[0140] (Preparation of Laminated Structure: Examples 1 to 3 and Comparative Examples 1 to 3) To examine the effect of the melt viscosity of the resin layer (B), laminate structures of Examples 1 to 3 and Comparative Examples 1 to 3 were prepared by the following method. The method for preparing the laminate structure of Example 1 is described below. A 25 μm thick polyethylene terephthalate film ("E5041" manufactured by Toyobo Co., Ltd.) was prepared as a first film. The resin composition (A1) obtained in Blending Example 1 above was applied to the film and dried at 80°C for 15 minutes to form a 5 μm thick resin layer (A). Subsequently, the resin composition (B1) obtained in Blending Example 2 above was applied to the surface of the resin layer (A) and dried at 80°C for 15 minutes to form a 95 μm thick resin layer (B). Next, a biaxially oriented polypropylene film ("E-201F" manufactured by Oji F-Tex Co., Ltd.) was laminated as a second film to obtain the laminate structure of Example 1. The laminated structures of Examples 2 to 3 and Comparative Examples 1 to 3 were obtained using the resin layer (A) and resin layer (B) shown in Table 5, the "E5041" as the first film, and the "E-201F" as the second film in the same production method as in Example 1. Each value in Table 5 indicates the film thickness (unit: μm).

[0141] [Table 5]

[0142] (Evaluation of lamination properties) The laminated structure obtained above was cut to a predetermined size, and the second film was peeled off. Subsequently, the exposed surface of the resin layer (B) was laminated to a single-sided flexible printed circuit board (copper thickness = 70 μm, imide substrate thickness = 25 μm) on which a circuit had been formed. Lamination was performed using a conveyor-type vacuum laminator (Nikko Materials Co., Ltd., CVP-300) under the following conditions: lamination temperature = 60°C, vacuum time = 20 seconds, and pressure time = 90 seconds. The state after lamination was observed with an optical microscope and evaluated according to the following criteria. The evaluation results are shown in Table 6. (Lamination evaluation criteria) ○: No abnormalities (no voids due to poor filling or bubbles due to air traps) ×: Abnormal (voids due to poor filling or bubbles due to air traps)

[0143] (Evaluation of edge covering ability) The cross section of a single line portion with a line width of 200 μm on the laminated substrate was observed, and the film thickness at the edge portion above the wiring was measured. The evaluation results are shown in Table 6. (Edge covering evaluation criteria) ◯: The film thickness at the edge portion remains at 5 μm or more. ×: The film thickness at the edge portion is less than 5 μm, or the edge is exposed.

[0144] [Table 6]

[0145] As is clear from Table 6, the laminate structures of Examples 1 to 3 exhibit good lamination properties and excellent edge covering properties, whereas, when the melt viscosity of the resin layer (B) is too low as in Comparative Example 1, fusion occurs before the predetermined vacuum level is reached, resulting in air entrapment (so-called air trapping), resulting in poor lamination. Furthermore, excessive outflow due to the low melt viscosity of the resin layer (B) also occurs, resulting in poor edge covering properties. On the other hand, when the melt viscosity of the resin layer (B) at 50°C is too high as in Comparative Examples 2 and 3, the resin layer (B) does not reach a viscosity suitable for lamination during the lamination process, resulting in poor lamination such as void entrapment. To achieve both good lamination properties and edge covering properties, it is necessary for the melt viscosity of the resin layer (B) to be within an appropriate range.

[0146] (Preparation of Laminated Structure: Examples 4 to 6 and Comparative Examples 4 and 5) To examine the effect of the melt viscosity of the resin layer (A), laminate structures were prepared in Examples 4 to 6 and Comparative Examples 4 and 5. These were obtained using the resin layers (A) and (B) shown in Table 7, the aforementioned "E5041" as the first film, and the aforementioned "E-201F" as the second film, in the same preparation method as in Example 1. Each value in Table 7 indicates the film thickness (unit: μm).

[0147] [Table 7]

[0148] (Evaluation of lamination and edge covering properties) The lamination properties and edge covering properties were evaluated for Examples 4 to 6 and Comparative Examples 4 and 5. The evaluation methods and criteria were the same as those described above (Preparation of laminated structures: Examples 1 to 3 and Comparative Examples 1 to 3). The evaluation results are shown in Table 8.

[0149] (Evaluation of developability) The uncured resin layer on each flexible printed wiring substrate, on which the resin layer had been formed as in the above-mentioned evaluation of lamination properties, was first exposed to 200 mJ / cm through a negative mask using an exposure device equipped with an ultra-high pressure mercury lamp (EXP-2960 manufactured by Oak Manufacturing Co., Ltd.). 2 The substrate was subjected to pattern exposure using a 300-μm thick film to form a via opening with a diameter of 200 μm. The substrate with the exposed resin layer was then heat-treated at 90°C for 30 minutes. The first film was then peeled off, and the substrate was sprayed with a 1% by mass aqueous solution of sodium carbonate at 30°C for 120 seconds for development. The state of pattern formation was observed, and the developability (alkali solubility) was evaluated. The evaluation results are shown in Table 8. (Developability evaluation criteria) ◯: The unexposed area exhibited developability, and a via pattern with a diameter of 200 μm was successfully formed. ×: The unexposed area did not exhibit sufficient developability, and a via pattern with a diameter of 200 μm could not be formed satisfactorily.

[0150] [Table 8]

[0151] The results in Table 8 show that in order to achieve both good edge covering properties and developability, the melt viscosity of the resin layer (A) needs to be within an appropriate range. That is, as shown in Comparative Example 4, when the melt viscosity of the resin layer (A) is low, the resin layer (A) flows out excessively, resulting in poor edge covering properties. Similarly, as shown in Comparative Example 5, when the melt viscosity of the resin layer (A) is high, it takes a long time to dissolve in alkali, resulting in poor developability. Furthermore, as shown in Example 6, it is possible for the resin layer (A) to exhibit sufficient performance even when it is colored.

[0152] (Preparation of Laminated Structure: Examples 7 to 9 and Comparative Examples 6 and 7) To examine the effect of the thickness of the resin layer (A), laminate structures of Examples 7 to 9 and Comparative Examples 6 and 7 were prepared. These were obtained using the resin layers (A) and (B) shown in Table 9, the aforementioned "E5041" as the first film, and the aforementioned "E-201F" as the second film, in the same preparation method as in Example 1. Note that each value in Table 9 indicates the film thickness (unit: μm).

[0153] [Table 9]

[0154] (Evaluation of lamination, edge covering and developability) The lamination properties, edge covering properties, and developability were evaluated for Examples 7 to 9 and Comparative Examples 6 and 7. The evaluation methods and criteria were the same as those described above (Preparation of laminated structures: Examples 4 to 6 and Comparative Examples 4 and 5). The evaluation results are shown in Table 10.

[0155] [Table 10]

[0156] As is clear from Table 10, when the resin layer (A) is not present as in Comparative Example 6, the resin layer (B) with a low melt viscosity flows out excessively, exposing the edges of the circuit, resulting in a significant deterioration in edge covering ability. Also, when the resin layer (A) is too thick as in Comparative Example 7, the resin layer does not flow sufficiently, resulting in a deterioration in lamination ability, and the alkali dissolution takes a long time, adversely affecting developability.

[0157] (Preparation of laminated structure: Examples 10 to 15) To examine the influence of the content of inorganic filler in the resin layer (B) and the thickness of the resin layer, laminate structures of Examples 10 to 15 were prepared. These were obtained using the resin layer (A) and resin layer (B) shown in Table 11, the "E5041" as the first film, and the "E-201F" as the second film, in the same preparation method as in Example 1. Note that each value in Table 11 indicates the film thickness (unit: μm).

[0158] [Table 11]

[0159] (Evaluation of lamination and edge covering properties) The lamination property and edge covering property were evaluated for Examples 10 to 15. The evaluation methods and evaluation criteria were the same as those described above (Production of laminated structures: Examples 1 to 3 and Comparative Examples 1 to 3). The evaluation results are shown in Table 12.

[0160] (Evaluation of resin overflow amount) The laminated structure obtained above was cut into a 10 cm x 10 cm piece, and the second film was peeled off. The exposed surface of the resin layer (B) was then laminated onto a copper substrate (244 mm x 254 mm x 0.8 mm double-sided CCL). Lamination was performed using a conveyor-type vacuum laminator (Nikko Materials Co., Ltd., CVP-300) under the following conditions: lamination temperature = 70°C, vacuum time = 20 seconds, and pressure time = 90 seconds. The laminated state was observed using an optical microscope and evaluated according to the following criteria. The evaluation results are shown in Table 12. (Evaluation criteria for resin overflow amount) ◎: Good (resin overflow after lamination is 0.3 mm or less) ○: No abnormalities (the amount of resin protruding after lamination is in the range of more than 0.3 mm and less than 1.0 mm) ×: Abnormal (resin overflow exceeds 1.0 mm or the dry film sticks to the transport film)

[0161] (Evaluation of film handling) The dry film (laminate structure) produced in the above example was cut to a width of 10 cm and a length of 30 cm, and the second film was quickly peeled off in an environment at room temperature of 21°C, and the presence or absence of damage to the resin layer was observed. As a result of the evaluation, no damage to the resin layer was observed in any of Examples 1 and 10 to 15.

[0162] [Table 12] The results in Table 12 reveal that the amount of resin protrusion during lamination is further reduced when an inorganic filler is contained. Therefore, although the resin layer (B) of the present invention exhibits sufficient performance even without containing an inorganic filler, it may contain an inorganic filler. Furthermore, when Examples 11 and 14, and 13 and 15 are compared, it is shown that the lamination properties, edge covering properties, and resin overflow amount are the same even when the thickness of the resin layer (B) is increased. This indicates that the laminate structure of the present invention can be suitably used as a dry film even when the total thickness of the resin layer (A) and the resin layer (B) is more than 80 μm and 300 μm or less.

Claims

1. A laminated structure including a first film, a resin layer, and a second film in this order, the resin layer includes a resin layer (A) in contact with the first film and a resin layer (B) in contact with the second film, the resin layer (A) contains an alkali-soluble resin having an imide ring, a photopolymerization initiator, and a thermosetting resin, the resin layer (B) contains an alkali-soluble resin having no imide ring, a polyfunctional photopolymerizable monomer, inorganic particles, and a thermosetting resin; the resin layer (A) has a melt viscosity at 50°C of 80,000 Pa s or more and 110,000 Pa s or less, and a melt viscosity at 100°C of 2,000 Pa s or more and 3,500 Pa s or less; the resin layer (B) has a melt viscosity at 50°C of 1,000 Pa s or more and 50,000 Pa s or less, and a melt viscosity at 100°C of 50 Pa s or more and 2,000 Pa s or less; A laminated structure, characterized in that the total thickness of the resin layer (A) and the resin layer (B) is more than 80 μm and 300 μm or less.

2. The laminate structure according to claim 1, wherein the resin layer (A) has a melt viscosity at 50°C of 90,000 Pa·s or more and 105,000 Pa·s or less and a melt viscosity at 100°C of 2,200 Pa·s or more and 3,200 Pa·s or less.

3. The laminate structure according to claim 1, wherein the ratio of the melt viscosity at 50°C to the melt viscosity at 100°C (50°C / 100°C) of the resin layer (A) is 30 or more and 40 or less.

4. The laminate structure according to claim 1, wherein the resin layer (B) has a melt viscosity at 50°C of 3000 Pa·s or more and 40000 Pa·s or less and a melt viscosity at 100°C of 200 Pa·s or more and 1600 Pa·s or less.

5. The laminate structure according to claim 1, wherein the ratio of the melt viscosity at 50°C to the melt viscosity at 100°C (50°C / 100°C) of the resin layer (B) is 10 or more and 100 or less.

6. The laminate structure according to claim 1, wherein the thickness of the resin layer (A) alone is 1 μm or more and 25 μm or less.

7. The laminate structure according to claim 1 , wherein the inorganic particles contained in the resin layer (B) include an inorganic filler.

8. The laminate structure according to claim 7 , wherein the content of the inorganic filler contained in the resin layer (B) is 10% by mass or more and 80% by mass or less in terms of solid content based on the total amount of the resin layer (B).

9. The laminate structure according to claim 7, wherein the inorganic filler contained in the resin layer (B) has an average particle size of 0.02 μm or more and 10 μm or less.

10. A cured product obtained by curing the resin layer in the laminate structure according to any one of claims 1 to 9.

11. An electronic component comprising the cured product according to claim 10.

12. A step of peeling off the second film in the laminate structure according to any one of claims 1 to 9, bonding the resin layer (B) to a substrate on which a circuit is formed, and arranging the first film and the resin layer on the substrate; an exposure step of irradiating a predetermined portion of the resin layer with active energy rays through the first film; a first heating step of heating the resin layer after the exposure step; a development step of peeling off the first film from the resin layer after the first heating step and removing a region of the resin layer after the exposure step that has not been irradiated with active energy rays; and a second heating step of heating the resin layer after the developing step; A method for forming a cured product, comprising:

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