Method for producing cured product, and cured product

Abstract

Provided are: a method for producing a cured product having an excellent appearance and excellent resolution even when a film is thick; and a cured product obtained using the method for producing a cured product. This method for producing a cured product comprises: a lamination step for obtaining a curable resin laminate by laminating curable resin layers using a dry film having a first film and a curable resin layer; and a curing step for curing the curable resin laminate to obtain a cured product, the content of the filler in the curable resin layer being 30 mass% or more based on the total solid content, the curable resin layer having a high filler content surface, which is a surface region in which the content of the filler is relatively high, and a low filler content surface, which is a surface region in which the content of the filler is relatively high, the low-filler-content surface is a surface region in which the filler content is relatively low, and the laminating step is a step in which the high-filler-content surface of one curable resin layer and the low-filler-content surface of the other curable resin layer are laminated in this order for a pair of adjacent curable resin layers.

Description

Technical Field

[0001] This invention relates to a method for manufacturing cured products and to cured products. Background Technology

[0002] In recent years, with the miniaturization and high performance of electronic devices, the insulating materials (solder resist) used in circuit boards are required to have properties such as high elasticity, low thermal expansion coefficient, and concealment, in addition to appearance. As a method to achieve these properties, methods for making solder resist into thick films are known.

[0003] For example, a solder resist having a plurality of coatings composed of a white curable composition containing titanium oxide laminated on top is disclosed (see Patent Document 1). Additionally, a method for forming a thick-film resist by exposing the film during each lamination of a plurality of photosensitive films and then developing it after lamination is disclosed (see Patent Document 2).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent document 1: Japanese Patent Application Publication No. 2015-5784.

[0007] Patent Document 2: Japanese Patent Application Publication No. 2004-157422. Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, while the technology in Patent Document 1 or Patent Document 2 can suppress the formation of pinholes caused by light shading due to foreign matter, unevenness caused by linear defects (coating streaks) due to concentration differences in the curable resin composition leads to damage to the appearance. Furthermore, if the solder resist is made into a thick film, it becomes difficult to perform fine patterning during the formation of the solder resist when exposing the cured resin layer (coating, dry film, etc.) composed of the curable resin composition, resulting in reduced resolution.

[0010] The present invention was made in view of the above-mentioned problems, and its objective is to provide a method for manufacturing a cured product with excellent appearance and excellent resolution even when thick film is used. Furthermore, its objective is to provide a cured product obtained using this method.

[0011] Methods for solving problems

[0012] One aspect of the present invention is a method for manufacturing a cured product. The method includes: a lamination step, wherein the cured resin layers are laminated using a dry film having a first film and a cured resin layer to obtain a cured resin laminate; and a curing step, wherein the cured resin laminate is cured to obtain a cured product, wherein the filler content in the cured resin layers is 30% by mass or more based on total solids, and the cured resin layers have a high filler content surface and a low filler content surface, the high filler content surface being a surface area with a relatively high filler content and the low filler content surface being a surface area with a relatively low filler content, the lamination step being a step in which the high filler content surface of one cured resin layer is sequentially laminated with the low filler content surface of another cured resin layer for a pair of adjacent cured resin layers.

[0013] In the method for manufacturing the cured product according to the above scheme, the filler is preferably silica.

[0014] In any of the above-described methods for manufacturing cured products, the thickness of the curable resin layer is preferably 25 μm or less.

[0015] In the method for manufacturing the cured product according to any of the above embodiments, it is preferred that the curing process includes an exposure step, in which the entire curable resin laminate is irradiated with energy rays and each of the curable resin layers contained in the curable resin laminate is simultaneously exposed.

[0016] In any of the above-described methods for manufacturing a cured product, the lamination process is preferably a process in which at least two or more layers of the curable resin are laminated.

[0017] In any of the above-described methods for manufacturing cured products, the thickness of the cured resin laminate is preferably 20 μm or more.

[0018] Another aspect of the present invention is a cured product. This cured product is a cured product composed of a plurality of resin cured layers stacked together, wherein the filler content in each resin cured layer is 30% by mass or more based on the total solids content. Each resin cured layer has a high filler content surface and a low filler content surface, the high filler content surface being a surface area with a relatively high filler content and the low filler content surface being a surface area with a relatively low filler content. For an adjacent pair of resin cured layers, the high filler content surface of one resin cured layer is stacked with the low filler content surface of the other resin cured layer.

[0019] The effects of the invention

[0020] According to the present invention, a method for manufacturing a cured material with excellent appearance and excellent resolution even when thickened, or a cured material obtained by using the method for manufacturing such a cured material, is available. Attached Figure Description

[0021] Figure 1 This is a schematic cross-sectional view of the cured product of this embodiment.

[0022] Figure 2 This is a schematic cross-sectional view of the dry film of this embodiment.

[0023] Figure 3 (a) to (c) are process cross-sectional views illustrating the manufacturing process (lamination process) of the curable resin laminate of this embodiment. Detailed Implementation

[0024] The embodiments of the present invention will now be described in detail. It should be noted that, unless otherwise specified, in this specification, the expression "a~b" in the description of numerical ranges means a or more and b or less.

[0025] When the compound described has isomers, all possible isomers can be used in this invention unless otherwise stated.

[0026] In this specification, "(meth)acrylamide" means both "acrylamide" and "methacrylamide". Similarly, "(meth)acrylate" means both "acrylate" and "methacrylate".

[0027] Weight-average molecular weight can be determined using well-known methods, such as gel permeation chromatography (GPC) as the molecular weight equivalent to polystyrene.

[0028] In this specification, "resin composition" is sometimes used to mean "curing resin composition". Additionally, "resin layer" is sometimes used to mean "curing resin layer".

[0029] In this specification, "curable resin laminate" refers to the state of the "cured product" before curing, and "curable resin layer" refers to the state of the "cured resin layer" before curing.

[0030] In this specification, "process" and "step" refer to the operation performed to achieve the purpose of the process or step, regardless of whether its content can be clearly distinguished from other processes or steps.

[0031] In this specification, when the upper and lower limits of the numerical range are recorded separately, all combinations of the lower and upper limits are actually recorded within the range of non-contradiction.

[0032] 1. Cured product

[0033] 1-1. Composition

[0034] Figure 1This is a schematic cross-sectional view of the cured product 10 of this embodiment. Figure 1 As shown, the cured product 10 of this embodiment is composed of multiple resin curing layers 11 to 14 stacked together.

[0035] In this embodiment ( Figure 1 The example shown in the previous embodiment is a four-layer resin curing layer 11 to 14, but this embodiment is not limited to this. The number of resin curing layers does not matter, as long as there are two or more layers. For example, it is preferable that there are two or more but less than seven resin curing layers, more preferably three or more but less than six layers, and even more preferably four layers. By setting the number of resin curing layers within the above range, a cured product 10 that maintains high elasticity, low thermal expansion coefficient, concealment, and excellent resolution can be formed.

[0036] 1-1-1. Resin Curing Layer

[0037] The resin cured layers 11 to 14 each contain fillers. Figure 1 The intensity of the filler color in each of the resin cured layers 11-14 indicates the distribution of the filler. Darker areas indicate a relatively higher filler content, while lighter areas indicate a relatively lower filler content. The filler distribution in each of the resin cured layers 11-14 varies in stages along the lamination direction. That is, the filler is distributed in each of the resin cured layers 11-14 in a manner that varies in stages along the lamination direction.

[0038] For example, the cured resin layer 11 has a surface region with a relatively high filler content, namely a high filler content surface 11a, and a surface region with a relatively low filler content, namely a low filler content surface 11b. In other words, the filler content in the high filler content surface 11a is higher than the filler content in the low filler content surface 11b. Preferably, the filler content is higher closer to the high filler content surface 11a and lower closer to the low filler content surface 11b. In other words, preferably, the filler is more distributed closer to the high filler content surface 11a and less distributed closer to the low filler content surface 11b.

[0039] Similar to the resin cured layer 11 described above, each resin cured layer 12-14 also has a high filler content surface 12a-14a and a low filler content surface 12b-14b. In other words, the filler content in the high filler content surfaces 12a-14a is higher than the filler content in the low filler content surfaces 12b-14b. Preferably, the filler content is higher closer to the high filler content surfaces 12a-14a and lower closer to the low filler content surfaces 12b-14b. In other words, preferably, the filler is more distributed closer to the high filler content surfaces 12a-14a and less distributed closer to the low filler content surfaces 12b-14b.

[0040] For the cured product 10 of this embodiment, for a pair of adjacent resin cured layers, the high filler content surface of one resin cured layer is stacked with the low filler content surface of the other resin cured layer.

[0041] More specifically, resin cured layers 11 and 12, which are adjacent resin cured layers, are stacked such that the high filler content surface 11a of resin cured layer 11 contacts the low filler content surface 12b of resin cured layer 12. Similarly, resin cured layers 12 and 13 are stacked such that the high filler content surface 12a of resin cured layer 12 contacts the low filler content surface 13b of resin cured layer 13. Resin cured layers 13 and 14 are stacked such that the high filler content surface 13a of resin cured layer 13 contacts the low filler content surface 14b of resin cured layer 14.

[0042] In the cured product 10 of this embodiment, the resin cured layers 11 to 14 each contain fillers. Therefore, compared with the conventional method, the elastic modulus of the cured product 10 can be further improved, and the coefficient of thermal expansion can be further reduced.

[0043] In the cured product 10 of this embodiment, resin cured layers 11 to 14 are stacked, and the distribution of filler in each layer varies stepwise along the stacking direction. Therefore, the distribution of filler is uniform as a whole in the cured product 10. As a result, the cured product 10 of this embodiment can further improve resolution compared to the case of thick film formation with a single layer. In addition, the difference in thermal expansion coefficient between the cured product 10 and the substrate is further reduced, so warpage of the cured product 10 can be further reduced when manufacturing printed wiring boards, etc. Furthermore, even if pinholes are generated in each resin cured layer 11 to 12, since multiple layers are stacked, the pinholes generated in each layer will be filled by other layers, and the appearance damage caused by pinholes can be suppressed as a whole in the cured product 10.

[0044] 1-2. Thickness

[0045] 1-2-1. Cured product

[0046] The thickness of the cured material 10 is preferably 10 μm or more, 15 μm or more, 20 μm or more, and preferably 65 μm or less, 60 μm or less, 55 μm or less.

[0047] If the thickness of the cured material 10 is set within the above-mentioned range, the cured material 10 becomes a thick film, thus increasing its elasticity. Therefore, when formed on a printed circuit board or the like, substrate displacement can be further suppressed. Furthermore, the concealment of circuits or damage can be further improved. The thermal expansion coefficient of the cured material 10 can be further reduced.

[0048] 1-2-2. Resin Curing Layer

[0049] The thickness of each resin cured layer 11 to 14 is preferably 3 μm or more, 5 μm or more, 8 μm or more, and preferably 25 μm or less, 20 μm or less, 15 μm or less.

[0050] If the thickness of the resin curing layers 11 to 14 is set within the above range, the distribution of filler is more uniform as a whole of the cured product 10, thus further improving the resolution.

[0051] In this embodiment ( Figure 1 The example shown is an example where the thickness of resin cured layers 11 to 14 is approximately the same. This embodiment is not limited to this, and the thicknesses of resin cured layers 11 to 14 can be different. In addition, the filler content in each resin cured layer, the filler content on the high filler content side, the filler content on the low filler content side, the presence or degree of the filler concentration gradient (in the thickness direction) in the resin cured layer, etc., can be the same or different among the plurality of resin cured layers.

[0052] 2. Dry film

[0053] Figure 2 This is a schematic cross-sectional view of the dry film D1 in this embodiment. Figure 2 As shown, the dry film D1 has a curable resin layer 21 and a first film P1. For the purpose of preventing the adhesion of dust and the like, a peelable second film (not shown) can be further laminated onto the surface of the curable resin layer 21 on the side opposite to the first film P1. The dry film D1 is used in the manufacturing process of the cured product 10, described later.

[0054] The following is for reference Figure 2 The structure and manufacturing method of the dry film D1 in this embodiment will be described.

[0055] 2-1. Composition

[0056] 2-1-1. Curing resin layer

[0057] The curable resin layer 21 is formed by coating the curable resin composition (described later) onto the first film P1, and drying the organic solvent contained in the formed curable resin composition layer through evaporation. The curable resin composition contains fillers.

[0058] Figure 2 The shades of the filler color in the cured resin layer 21 indicate the distribution of the filler. Darker areas indicate a relatively higher filler content, while lighter areas indicate a relatively lower filler content. The filler content varies in stages along the lamination direction within the cured resin layer 21. That is, the filler is distributed in the cured resin layer 21 in a staged manner along the lamination direction.

[0059] For example, the curable resin layer 21 has a surface region with a relatively high filler content, namely a high filler content surface 21a, and a surface region with a relatively low filler content, namely a low filler content surface 21b. In other words, the filler content in the high filler content surface 21a is higher than the filler content in the low filler content surface 21b. Preferably, the filler content is higher closer to the high filler content surface 21a and lower closer to the low filler content surface 21b. In other words, preferably, the filler is more distributed closer to the high filler content surface 21a and less distributed closer to the low filler content surface 21b.

[0060] Typically, the filler in a curable resin composition has a higher specific gravity than other components in the composition. Therefore, when the curable resin composition is coated onto a first film P1 to form a curable resin composition layer, it can be assumed that the filler gradually settles towards the first film P1 under gravity. Then, by evaporating and drying the organic solvent contained in the curable resin composition layer, a dry film D1 having the first film P1 and the curable resin layer 21 can be obtained. Thus, the curable resin layer 21 is formed with the filler distribution in the curable resin layer 21 varying in stages along the direction of gravity (a staged high filler content on the first film P1 side). As a result, the curable resin layer 21 has a surface region with a relatively high filler content, i.e., a high filler content surface 21a, and a surface region with a relatively low filler content, i.e., a low filler content surface 21b (refer to...). Figure 2 ).

[0061] The thickness of the curable resin layer 21 is appropriately set within the range of preferably 3 to 25 μm, more preferably 3 to 20 μm, and even more preferably 3 to 15 μm.

[0062] 2-1-2. First membrane

[0063] The first film P1 in this embodiment serves to support each curable resin layer 21. As the first film P1, any known film can be used without particular limitation; for example, films made of thermoplastic resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PAN), polyimide films, polyamide-imide films, polypropylene films, and polystyrene films are preferably used. Among these, polyester films are preferred from the viewpoints of heat resistance, mechanical strength, and operability. Furthermore, laminates of these films can also be used as the first film.

[0064] Furthermore, from the viewpoint of improving mechanical strength, the thermoplastic resin film described above is preferably a film that extends in a uniaxial or biaxial direction.

[0065] The thickness of the first membrane is not particularly limited; for example, it can be set to 10 μm to 150 μm.

[0066] 2-1-3. Second membrane

[0067] The second film in this embodiment serves to protect the surface of the cured resin layer 21. As the second film, any film with a weaker adhesive force than the adhesive force between the cured resin layer 21 and the first film P1 during peeling is acceptable. For example, polyethylene film, polytetrafluoroethylene film, polypropylene film, or surface-treated paper can be used.

[0068] The thickness of the second film is not particularly limited and can be appropriately selected in the range of approximately 10 to 150 μm depending on the application. Demolding treatment can be performed on the surface in contact with the curable resin layer 21 of the second film.

[0069] 2-2. Dry film manufacturing method

[0070] The method for manufacturing the dry film according to this embodiment includes: a preparation step of preparing a curable resin composition; and a fabrication step of fabricating a dry film having a first film and a curable resin layer. Each step will be described below.

[0071] 2-2-1. Preparation process

[0072] In the preparation process, the various raw materials of the curable resin composition described later are mixed and stirred to prepare the composition.

[0073] 2-2-1-1. Curable resin composition

[0074] A curable resin composition is a resin composition that constitutes a curable resin layer. The curable resin composition includes an alkali-soluble resin, a photopolymerization initiator, a filler, and other components (additives) as needed. The components included in the curable resin composition are described below.

[0075] 2-2-1-1-1. Alkali-soluble resin

[0076] The alkali-soluble resin used in this embodiment is not particularly limited, and known substances can be used. Furthermore, the alkali-soluble resin used in this embodiment can be either a negative or positive form, more preferably a negative form. Examples include compounds having two or more phenolic hydroxyl groups, carboxyl-containing resins, compounds having both phenolic hydroxyl and carboxyl groups, and compounds having two or more thiol groups.

[0077] Among these, carboxyl-containing resins or phenolic resins exhibit excellent adhesion to the substrate and are therefore preferred. Furthermore, carboxyl-containing resins offer superior developability and are therefore more preferred. The carboxyl-containing resin can be a photosensitive resin containing carboxyl groups and having olefinic unsaturated groups, or it can be a carboxyl-containing resin without olefinic unsaturated groups.

[0078] Specific examples of carboxyl-containing resins include the following compounds (which may be oligomers or polymers).

[0079] (1) A carboxyl-containing resin obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with compounds containing unsaturated groups such as styrene, α-methylstyrene, lower alkyl (meth)acrylates, and isobutylene.

[0080] (2) A carboxyl-containing urethane resin produced by the addition polymerization reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with diols containing carboxyl groups such as dimethylolpropionic acid and dimethylolbutyric acid, and diols containing carboxyl groups such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A epoxy alkane adduct diols, and compounds with phenolic hydroxyl groups and alcoholic hydroxyl groups.

[0081] (3) A carbamate resin containing a terminal carboxyl group is obtained by reacting the end of a carbamate resin produced by the addition polymerization reaction of diisocyanate compounds such as aliphatic diisocyanate, branched aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate with diol compounds such as polycarbonate polyol, polyether polyol, polyester polyol, polyolefin polyol, acrylic polyol, bisphenol A epoxy alkane adduct diol, and compounds with phenolic hydroxyl or alcoholic hydroxyl groups with an acid anhydride.

[0082] (4) A carboxyl-containing urethane resin produced by the addition polymerization reaction of diisocyanate with bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin and other bifunctional epoxy resins, methacrylates or their partial anhydride modifications, carboxyl-containing diol compounds and diol compounds.

[0083] (5) In the resin synthesis of (2) or (4) above, a carboxyl urethane resin containing a carboxyl group is obtained by adding a compound such as (meth)acrylic acid hydroxyalkyl ester that has one hydroxyl group and one or more (meth)acryloyl groups in the molecule and performing terminal (meth)acryloylation.

[0084] (6) In the resin synthesis of (2) or (4) above, a carboxyl-containing urethane resin is obtained by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as the reactant of isophorone diisocyanate and pentaerythritol triacrylate, and performing terminal (meth)acryloylation.

[0085] (7) A carboxyl-containing resin is formed by reacting a multifunctional epoxy resin with (meth)acrylic acid to add phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride and other dicarboxylic anhydrides to the hydroxyl groups present in the side chain.

[0086] (8) A multifunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of a bifunctional epoxy resin with epichlorohydrin is reacted with (meth)acrylic acid to form a carboxyl-containing resin by adding a dicarboxylic acid anhydride to the generated hydroxyl groups.

[0087] (9) A polyfunctional oxocyclic butane resin is reacted with a dicarboxylic acid to form a diacid anhydride on the generated primary hydroxyl group, resulting in a polyester resin containing a carboxyl group.

[0088] (10) A compound having multiple phenolic hydroxyl groups in one molecule reacts with ethylene oxide, propylene oxide, or other epoxides to obtain a reaction product that reacts with a monocarboxylic acid containing unsaturated groups, and the resulting reaction product reacts with a polyacid anhydride to obtain a carboxyl-containing resin.

[0089] (11) A reaction product obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with cyclic carbonates such as ethylene carbonate and propylene carbonate, and then reacting the product with a monocarboxylic acid containing unsaturated groups, and then reacting the product with a polyacid anhydride to obtain a carboxyl-containing resin.

[0090] (12) An epoxy compound having multiple epoxy groups in one molecule is reacted with a compound having at least one alcoholic hydroxyl group and a phenolic hydroxyl group in one molecule, such as p-hydroxyphenylethanol, and a monocarboxylic acid containing unsaturated groups, such as (meth)acrylic acid, so that the alcoholic hydroxyl group of the reaction product reacts with maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, adipic anhydride, etc., to obtain a carboxyl-containing resin.

[0091] (13) A carboxyl-containing resin formed by further adding compounds having an epoxy group and one or more (meth)acryloyl groups to the carboxyl-containing resins described in (1) to (12) above.

[0092] Among the aforementioned carboxyl-containing resins, it is preferable to include at least one of the carboxyl-containing resins (7), (8), (10), (11), and (13) mentioned above. From the viewpoint of further improving insulation reliability, it is more preferable to include the carboxyl-containing resin described in (10) or (11) mentioned above.

[0093] Within the scope that does not impair the effects of the present invention, the acid value of the alkali-soluble resin is not particularly limited, for example, it is 20 to 200 mg KOH / g, preferably 40 to 150 mg KOH / g. When the acid value of the alkali-soluble resin is within this range, it becomes easier to develop the cured resin laminate after exposure using an alkaline aqueous solution, and it becomes easier to draw the normal cured pattern.

[0094] The weight-average molecular weight of the alkali-soluble resin varies depending on the resin skeleton, and can be set to 1,500 to 150,000, preferably 1,500 to 100,000, more preferably 1,500 to 50,000, and particularly preferably 1,500 to 30,000. Within this weight-average molecular weight range, the non-stick properties, storage stability, moisture resistance of the cured resin laminate after exposure, and developability are excellent, further suppressing film reduction and resolution degradation during development.

[0095] Alkali-soluble resins can be used alone or in combination of several types.

[0096] 2-2-1-1-2. Photopolymerization initiator

[0097] The photopolymerization initiator in this embodiment is not particularly limited, and any known photopolymerization initiator or photoradical initiator can be used.

[0098] Examples of bis-(2,6-dichlorobenzoyl)phenylphosphine oxides, such as bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxides, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxides, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxides, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxides, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxides, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxides, and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxides, are diacylphosphine oxides. Monoacylphosphine oxides include 2,6-dimethoxybenzoyl diphenylphosphine oxide, 2,6-dichlorobenzoyl diphenylphosphine oxide, methyl 2,4,6-trimethylbenzoyl phenylphosphine ester, 2-methylbenzoyl diphenylphosphine oxide, isopropyl tervapotranyl phenylphosphine ester, and 2,4,6-trimethylbenzoyl diphenylphosphine oxide. Hydroxyacetophenones include 1-hydroxy-cyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanoyl)-benzyl]phenyl}-2-methyl-propane-1-one, and 2-hydroxy-2-methyl-1-phenylpropane-1-one. Benzoin, benzoyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether, and other benzoin derivatives; Benzoin alkyl ethers; Benzophenone, p-methylbenzophenone, Mischel ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bis(diethylamino)benzophenone and other benzophenone derivatives; Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholin-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butanone-1,2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, N,N-dimethylaminoacetophenone, and other acetophenone derivatives; Thioxanone, 2-ethylthioxanone, 2-isopropylthioxanone, 2,4-dimethylthioxanone, 2,4-diethylthioxanone, 2-chlorothioxanone, 2,4-diisopropylthioxanone and other thioxanone derivatives; Anthraquinones, including anthraquinones, chloroanthraquinones, 2-methylanthraquinones, 2-ethylanthraquinones, 2-tert-butylanthraquinones, 1-chloroanthraquinones, 2-pentylanthraquinones, and 2-aminoanthraquinones; Ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; Benzoate esters such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethylbenzoate, and ethyl p-dimethylbenzoate; Oxime esters such as 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyl oxime)], acetone, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime); Dicarboxylate derivatives such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro)-3-(1H-pyrrolo-1-yl)phenyl)titanium and bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrrolo-1-yl)ethyl)phenyl]titanium; Phenyl disulfides such as 2-nitrofluorene, butylin, anisolein ether, azobisisobutyronitrile, and tetramethylthiuram disulfide. These substances can be used alone or in combination.

[0099] There is no particular limitation on the amount of photopolymerization initiator, but for example, it is preferably 0.5 to 20% by mass relative to 100% by mass of the alkali-soluble resin. When the amount of photopolymerization initiator is within this range, it is possible to obtain a curable resin composition and cured product with better surface curing properties, less halos, and better resolution.

[0100] 2-2-1-1-3. Packing

[0101] Examples of fillers include inorganic fillers and organic fillers.

[0102] As inorganic fillers, metal oxides such as silicon dioxide, aluminum oxide, and titanium oxide can be used; metal hydroxides such as aluminum hydroxide and magnesium hydroxide; clay minerals such as talc and mica; fillers with perovskite-type crystalline structures such as barium titanate and strontium titanate; and boron nitride, aluminum borate, barium sulfate, and calcium carbonate.

[0103] As organic fillers, fluoropolymers such as polytetrafluoroethylene (PTFE), tetrafluoroethylene / ethylene copolymer (ETFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF) can be used; as well as hydrocarbon resin fillers such as cyclic olefin polymer (COP) and cyclic olefin copolymer (COC).

[0104] The filler is preferably an inorganic filler. From the viewpoint of further improving the heat resistance and mechanical properties of the cured product, silica is more preferred. The average particle size of silica is preferably 0.01 to 5 μm, more preferably 0.01 to 1 μm. Here, the average particle size can be determined using a commercially available laser diffraction / scattering particle size distribution measuring device, based on the measured value of particle size distribution according to laser diffraction / scattering method, as the median particle size (d50, volume basis) based on the cumulative distribution. In addition, the average particle size of silica is a value obtained by measuring the powdery material before preparing (pre-stirring, mixing) the resin composition as described above.

[0105] Silica is preferably formulated in a slurry state. Formulating it in a slurry state facilitates high dispersibility and further suppresses agglomeration, thus making the processing of silica with an average particle size within the aforementioned specific range easier. Furthermore, formulating it in a slurry state makes it easier to maintain the precision of the resin layer film thickness (in 1 μm units).

[0106] The filler is preferably a surface-treated filler (surface-treated filler). By surface-treating the filler, a cured product with higher elasticity and lower thermal expansion coefficient can be obtained without compromising resolution.

[0107] The filler content in the curable resin composition is preferably 30% by mass or more, more preferably 30 to 90% by mass or more, and more preferably 50 to 90% by mass or less, based on the total solids content. By setting the filler content within the above range, the elastic modulus of the cured product can be further improved, and the coefficient of thermal expansion of the cured product can be further reduced.

[0108] 2-2-1-1-4. Organic solvents

[0109] There are no particular limitations on the organic solvents used; examples include chloroform, dichloromethane, and toluene. Additionally, solvents such as N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), cyclohexanone, propylene glycol monomethyl ether acetate (PMA), diethylene glycol monoethyl ether acetate (CA), methyl ethyl ketone, ethyl acetate, and anisole can be used. Only one organic solvent can be used, or two or more can be used.

[0110] 2-2-1-1-5. Other ingredients / additives

[0111] Other components may include photocurable and thermocurable compounds other than the alkali-soluble resins mentioned above. Additionally, as additives, they may include colorants; antisettling agents; polymerization inhibitors; UV absorbers; silane coupling agents; plasticizers; flame retardants; antistatic agents; antiaging agents; antioxidants; antibacterial / mildew inhibitors; defoamers; leveling agents; thickeners; adhesion promoters; thixotropic promoters; photoinitiators; sensitizers; photoalkalizing agents; thermoplastic resins; elastomers; organic fillers; release agents; surface treatment agents; dispersants; dispersing aids; surface modifiers; stabilizers; phosphors, etc. These substances can be used individually or in combination.

[0112] 2-2-2. Production Process

[0113] In the manufacturing process, the curable resin composition prepared in the preparation process is coated onto the first film P1 to form a curable resin composition layer, and then the organic solvent is evaporated and dried to produce a dry film D1 having the first film P1 and the curable resin layer 21.

[0114] In the manufacturing process, a comma-type coating machine, doctor blade coating machine, lip coating machine, rod coating machine, extrusion coating machine, reverse coating machine, transfer roller coating machine, gravure coating machine, spray coating machine, etc., are used to coat the curable resin composition, which has been adjusted to an appropriate viscosity using organic solvents in the preparation process, onto the first film P1 at a uniform thickness. The coated curable resin composition forms a curable resin composition layer. Then, typically, the organic solvent contained in the curable resin composition layer is evaporated and dried at a temperature of 50–130°C for 1–30 minutes, thereby forming the curable resin composition layer 21. Through this operation, a dry film D1 having the first film P1 and the curable resin layer 21 is obtained (see reference). Figure 2 ).

[0115] In this embodiment, during the manufacturing process of the cured product 10 described later, at least the same number of dry films as the number of resin curing layers 11 to 14 of the cured product 10 are required. For example, in the cured product 10 of this embodiment, four resin curing layers 11 to 14 are stacked. Therefore, it is preferable to produce at least four dry films. That is, a dry film D1 having the first film P1 and the curable resin layer 21 described above (refer to...) Figure 2 Like the dry film D2 having a first film P2 and a curable resin layer 22, the dry film D3 having a first film P3 and a curable resin layer 23, and the dry film D4 having a first film P4 and a curable resin layer 24, it is preferable to manufacture at least four dry films D1 to D4 respectively. Since the structure and manufacturing method of dry films D2 to D4 are the same as those of dry film D1, illustrations and descriptions are omitted.

[0116] 3. Methods for manufacturing cured products

[0117] The cured product 10 of this embodiment is manufactured by sequentially laminating curable resin layers onto a substrate to form a curable resin laminate and then curing the curable resin laminate. The method for manufacturing the cured product 10 of this embodiment includes: a lamination step, in which the curable resin layers are laminated onto a substrate using the aforementioned dry film to obtain a curable resin laminate; and a curing step, in which the curable resin laminate is cured to obtain the cured product 10. Each step will be described below.

[0118] 3-1. Lamination process

[0119] Figure 3 (a) to (c) are process cross-sectional views showing the manufacturing process (lamination process) of the curable resin laminate 20 of this embodiment. The lamination process involves laminating curable resin layers 21 to 24 onto the substrate Q using the aforementioned dry films D1 to D4 to obtain the curable resin laminate 20. The lamination process includes the bonding step and the lamination step described later. Hereinafter, refer to... Figure 3 Each step is explained.

[0120] 3-1-1. Adhesion Steps

[0121] Figure 3 (a) is a cross-sectional view of the process after the dry film D1 is laminated onto the substrate Q. For example... Figure 3 As shown in (a), in the bonding step, the dry film D1 is bonded to the substrate Q by lamination with the curable resin layer 21 facing the substrate Q.

[0122] Specifically, firstly, the second film is peeled off from the dry film D1, which is sequentially stacked with the first film P1, the curable resin layer 21, and the second film (not shown). Then, with the curable resin layer 21 facing the substrate Q, the dry film D1 is bonded to the substrate Q using a vacuum laminator at a temperature of 80–110°C and a pressure of 0.5 MPa {Ref. 1} Figure 3 (a)}.

[0123] The substrate Q is not particularly limited. Besides printed wiring boards or flexible printed wiring boards with circuits pre-formed from copper or the like, examples include copper-clad laminates for high-frequency circuits made of materials such as paper phenolic resin, paper epoxy resin, glass cloth epoxy resin, glass polyimide, glass cloth / non-woven epoxy resin, glass cloth / paper epoxy resin, synthetic fiber epoxy resin, fluoropolymer-polyethylene-polyphenylene ether, and polyphenylene ether-cyanate. Examples of copper-clad laminates include all grades (FR-4, etc.); as well as metal substrates, polyimide films, polyethylene terephthalate (PET) films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, and wafer boards. The substrate Q can be, for example, a substrate that has undergone known pretreatment such as chemical polishing. Examples of such pretreatments include etching (e.g., etching using organic acids; 1μm etching), anti-discoloration treatment, water washing, and drying. For substrate Q, from the viewpoint of adhesion to the cured product, it is preferable to use a pretreated substrate, and more preferably a substrate that has undergone chemical polishing treatment.

[0124] 3-1-2. Stacking Steps

[0125] In the lamination step, the first film P1 is peeled off from the dry film D1 bonded to the substrate Q in the bonding step, and then another dry film D2 is used to laminate the curable resin layer 22 onto the side of the curable resin layer 21 opposite to the substrate Q. The curable resin layers 23 and 24 are also laminated sequentially in the same manner to obtain the curable resin laminate 20.

[0126] Specifically, from the dry film D1 {refer to} the cured resin layer 21 bonded to the substrate Q in the bonding step Figure 3 (a) Peel off the first film P1. On the other hand, peel off the second film from the dry film D2, which is sequentially laminated with the first film P2, the curable resin layer 22, and the second film (not shown). The dry film D2 having the curable resin layer 22 is laminated using a laminator or the like, with the curable resin layer 21 facing the curable resin layer 22. Through this operation, the curable resin layer 22 is laminated onto the side of the curable resin layer 21 opposite to the substrate Q {Ref.} Figure 3 (b)}. In the curable resin layers 23 and 24, the same operation as that for the curable resin layer 22 is repeated, and the curable resin laminate is sequentially stacked by lamination to produce a curable resin laminate 20 {refer to...} Figure 3 (c)}.

[0127] Figure 3(c) is a schematic cross-sectional view of the curable resin laminate 20 obtained by laminating the curable resin layers 21-24 of this scheme onto the substrate Q, i.e., the curable resin laminate 20 in the stage where the lamination process is completed. Figure 3 As shown in (c), at the end of the lamination step, the curable resin layer 24, which is laminated with the dry film D4, is positioned at the position furthest from the substrate Q (outermost layer) of the curable resin laminate 20. After the lamination step is completed, the curable resin laminate 20 is in a state where the first film P4 does not peel off from the dry film D4 having the curable resin layer 24 laminated on the outermost layer, and the first film P4 is adhered to the curable resin laminate 20 (curable resin layer 24). In this state, the exposure step (irradiation with active energy rays included in the curing process) described later is performed. The first film P4 peels off after the exposure step is completed.

[0128] The lamination process is preferably carried out under at least the following different conditions: a first lamination condition and a second lamination condition.

[0129] 3-1-2-1. First lamination condition

[0130] Preferably, under the first lamination condition, vacuum lamination is performed using a vacuum laminator under pressure and heating. The pressure condition is preferably 0.1–1.0 MPa, the heating condition is preferably 40–80°C, and the lamination time is preferably 20–40 seconds.

[0131] By performing vacuum lamination, even if there are unevennesses on the surface of the circuit board when using a substrate with circuits formed as the substrate, the dry film adheres tightly to the circuit board, so no air bubbles are mixed in, and the filling effect of the recesses on the surface of the substrate is further improved.

[0132] 3-1-2-2. Second lamination conditions

[0133] Preferably, lamination is performed under the following pressure / heating conditions during the second lamination process. The preferred pressure conditions are 5–10 kgf / cm². 2 The preferred heating conditions are 40–100°C, and the preferred lamination time is 50–70 seconds.

[0134] Under the first lamination condition and the second lamination condition, the heating conditions described above are set respectively, thereby maintaining a higher viscosity of the curable resin composition. Therefore, it is possible to further suppress the flow of fillers and resins in each of the curable resin layers 21 to 24, maintain the distribution of fillers and the layer structure, and form the curable resin laminate 20 on the substrate Q.

[0135] As described above, in this embodiment, the curable resin layers 21 to 24 are laminated by laminating dry films D1 to D4, thus easily maintaining the layer structure. Furthermore, the flow of filler within the curable resin layers is relatively suppressed, allowing curing to proceed while the filler distribution varies in stages along the lamination direction. Therefore, as a whole, the distribution of filler is homogenized in the cured product 10, further improving resolution.

[0136] In contrast, conventional methods such as screen printing, which involve multiple coating layers, are prone to over-drying, making it difficult to maintain the layer structure. Furthermore, even when fillers are present, their distribution tends to deviate beyond necessary limits due to the tendency for fillers to settle within the layer, resulting in uneven filler distribution as a whole in the cured product.

[0137] 3-2. Curing process

[0138] In the curing process, the curable resin laminate 20 prepared in the lamination process is cured to obtain cured material 10. The curing process includes the exposure step, development step, and finishing step, which will be described later. Each step is explained below.

[0139] 3-2-1. Exposure Steps

[0140] In the exposure step, the curable resin laminate 20 produced in the lamination process is irradiated (exposed) with active energy rays.

[0141] Specifically, after fabricating the curable resin laminate 20 in the lamination process, the entire curable resin laminate 20 is selectively irradiated (exposed) with active energy rays using a photomask with a predetermined pattern. At this time, it is preferable to simultaneously expose each of the curable resin layers 21 to 24 included in the curable resin laminate 20 (one-time exposure). After exposure, it is preferable to leave it at room temperature for 10 to 180 minutes. Then, the first film P4, which is adhered to the outermost curable resin layer 24 of the curable resin laminate 20, is peeled off.

[0142] When the entire curable resin laminate 20 is exposed in a single exposure, and each curable resin layer 21 to 24 contained in the curable resin laminate 20 is exposed simultaneously, a pattern can be formed and developed in a shorter time compared to the case where each layer is exposed individually. Furthermore, compared to the case where each curable resin layer 21 to 24 is exposed individually during lamination, finer patterning is possible.

[0143] As an exposure machine for irradiating active energy rays, any device equipped with a high-pressure mercury lamp, ultra-high-pressure mercury lamp, metal halide lamp, or mercury short-arc lamp that irradiates active energy rays in the range of 350–450 nm is acceptable. Furthermore, a direct drawing device (e.g., a laser direct imaging device that directly draws images using laser light from CAD (Computer-Aided Design) data from a computer) can also be used. The lamp source or laser source of the direct drawing machine can be a light source with a maximum wavelength in the range of 350–450 nm. The exposure dose used to form the image varies depending on the film thickness, and can typically be set from 10 to 1000 mJ / cm². 2 Preferably, it can be set to 20–800 mJ / cm 2 Within the range.

[0144] 3-2-2. Developing Steps

[0145] In the developing step, the unexposed areas are developed using an alkaline aqueous solution.

[0146] Specifically, the unexposed portion of the curable resin laminate 20, where the first film P4 has been peeled off in the above exposure step, is developed (e.g., for 60 to 90 seconds) with a dilute alkaline aqueous solution (e.g., 0.3 to 3% by mass of sodium carbonate or potassium carbonate aqueous solution) to form a pattern on the curable resin laminate 20. After patterning, it can be washed with a washing solution.

[0147] As a developing process utilizing alkaline aqueous solutions, methods such as immersion, spraying, misting, and brushing can be employed. The developing solution can include alkaline aqueous solutions of potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, and amines. These can also be used in combination.

[0148] 3-2-3. Finishing Steps

[0149] In the finishing step, the curable resin laminate 20, which has been patterned in the above-described developing step, is irradiated with active energy rays and then heated and cured (e.g., 100–220°C). In the finishing step, the curable resin laminate 20 is completely cured to form a cured product 10.

[0150] Example

[0151] The present invention will be described below by way of examples and comparative examples, but the present invention is not limited thereto.

[0152] (Synthesis of alkali-soluble resin solution)

[0153] In a high-pressure reactor equipped with a thermometer, a nitrogen introduction device that also serves as an epoxy alkane introduction device, and a stirring device, 119.4 parts by weight of phenolic varnish-type cresol resin (manufactured by Showa Denko, Shonol CRG951, OH equivalent: 119.4), 1.19 parts by weight of potassium hydroxide, and 119.4 parts by weight of toluene were introduced. While stirring, nitrogen replacement was carried out in the system, and the temperature was increased. Then, 63.8 parts of propylene oxide were slowly added dropwise at 125–132°C and 0–4.8 kg / cm³. 2 The reaction was carried out for 16 hours. Then, the mixture was cooled to room temperature, and 1.56 parts of 89% phosphoric acid were added to the reaction solution and mixed. Potassium hydroxide was then added to neutralize the solution, yielding a propylene oxide reaction solution of phenolic varnish-type cresol resin with a non-volatile content of 62.1% and a hydroxyl value of 182.2 mg KOH / g (307.9 g / equivalent). This was obtained by adding an average of 1.08 moles of propylene oxide per 1 equivalent of phenolic hydroxyl group. 293.0 parts of the obtained propylene oxide reaction solution of phenolic varnish-type cresol resin, 43.2 parts of acrylic acid, 11.53 parts of methanesulfonic acid, 0.18 parts of methyl hydroquinone, and 252.9 parts of toluene were introduced into a reactor equipped with a stirrer, thermometer, and air blow-in pipe. The reaction was carried out at 110°C for 12 hours while blowing air in at a rate of 10 ml / min and stirring. The water produced in the reaction was used as an azeotropic mixture with toluene, and 12.6 parts of water were distilled off. Then, the mixture was cooled to room temperature and neutralized with 35.35 parts of a 15% sodium hydroxide aqueous solution, followed by washing with water. Toluene was then replaced with 118.1 parts of diethylene glycol monoethyl ether acetate using an evaporator and removed by distillation to obtain a phenolic varnish-type acrylate resin solution. Then, 332.5 parts of the obtained phenolic varnish-type acrylate resin solution and 1.22 parts of triphenylphosphine were introduced into a reactor equipped with a stirrer, thermometer, and air blow-in pipe. While blowing air in at a rate of 10 ml / min and stirring, 60.8 parts of tetrahydrophthalic anhydride were slowly added. The reaction was carried out at 95–101 °C for 6 hours, cooled, and removed. In the manner described above, a carboxyl-containing alkali-soluble resin solution with 65% non-volatile components and an acid value of 87.7 mg KOH / g in the solid was obtained.

[0154] (Preparation of surface-treated filler (silica treated with methacryloxysilane))

[0155] 70g of spherical silica (SFP-30M manufactured by Denka Co., Ltd.), 28g of PMA (propylene glycol monomethyl ether acetate) as a solvent, and 2g of KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd. as a silane coupling agent were uniformly dispersed to obtain a silica solvent dispersion.

[0156] <Preparation of Curable Resin Compositions>

[0157] The components were compounded according to the formulations shown in Formulation Examples A to C in Table 1 below, and premixed using a mixer. Then, they were dispersed and kneaded using a bead mill to prepare the curable resin compositions of Formulation Examples A to C.

[0158] Table 1

[0159] The proportions in Table 1 represent parts by mass.

[0160] The details of each component in Table 1 are as follows.

[0161] 1: The above-synthesized alkali-soluble resin solution containing olefinic unsaturated groups.

[0162] 2: Irgacure TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide) manufactured by BASF Japan.

[0163] 3: JMT784 (Titanium-based photopolymerization initiator) manufactured by Yueyang Jinmaotai Technology Co., Ltd.

[0164] 4: EPICLON N-730A (phenolic varnish epoxy resin) manufactured by DIC Company.

[0165] 5: EPICLON N-870 (Bisphenol A phenolic varnish epoxy resin) manufactured by DIC Company.

[0166] 6: The solvent dispersion of silica prepared above after surface treatment with methacryloxysilane.

[0167] 7: Bentone 38 manufactured by Toshin Kasei Co., Ltd.

[0168] 8: Eastman Chemical Company manufactures CAP-504-0.2DPM30.

[0169] 9: Melamine manufactured by Nissan Chemical Industries, Ltd.

[0170] 10: KAYACURE DETX-S (2,4-diethylthioxanone) manufactured by Nippon Kayaku Co., Ltd.

[0171] 11: Blue and yellow pigments.

[0172] [Examples 1-9, Comparative Examples 1-7]

[0173] <Evaluation of substrate fabrication>

[0174] Evaluation substrates for each embodiment and comparative example were fabricated according to the following steps, with the layer structure and thickness of each layer as shown in Tables 2 and 3.

[0175] The above-described curable resin composition was coated onto a polyethylene terephthalate film (hereinafter also referred to as PET film) (manufactured by Toyobo Co., Ltd., E5041) (first film) with a size of 300 mm × 130 mm and a thickness of 25 μm, with the film thickness after drying as shown in Table 2. The film was then heated and dried to form a first layer of cured resin. Next, a polypropylene film (manufactured by Oji F-tex Co., Ltd., MA411) (second film) with a size of 300 mm × 100 mm and a thickness of 15 μm was laminated onto the cured resin layer to form a dry film. The same operation was performed to produce dry films having each subsequent layer of cured resin, corresponding to the number of laminates.

[0176] As a substrate, a double-sided printed wiring board measuring 150mm × 95mm and 0.4mm thick was used and chemically ground to a depth equivalent to 1.0μm using a MECetchBOND CZ-8100 manufactured by MAG Corporation. A 150mm × 90mm dry film with a first curable resin layer was cut out, and after peeling off the polypropylene film (second film), the dry film was laminated to the pretreated substrate with the curable resin layer facing each other using a CVP-600 dual-chamber vacuum laminator (manufactured by Nikko-Materials Co. Ltd.) under the following conditions.

[0177] Lamination temperature: 80℃.

[0178] Vacuuming: 30 seconds, 3 hPa.

[0179] Lamination: 30 seconds, 0.5 MPa.

[0180] After peeling off the first film from the dry film adhered to the substrate to expose the cured resin layer, a dry film containing a second cured resin layer is cut into 150mm × 90mm pieces. The second film is then peeled off, and the two layers are laminated together with the first and second cured resin layers facing each other. Similarly, subsequent cured resin layers are layered sequentially to create a cured resin laminate on the substrate. The outermost PET film of the resulting cured resin laminate does not peel off, resulting in a state where the PET film is adhered (cured resin laminate with PET film). The lamination of the subsequent cured resin layers is performed under two different conditions.

[0181] (First lamination condition)

[0182] Lamination temperature: 80℃.

[0183] Vacuuming: 30 seconds, 3 hPa.

[0184] Lamination: 30 seconds, 0.5 MPa.

[0185] (Second lamination condition)

[0186] Lamination temperature: 100℃.

[0187] Pressure: 60 seconds, 8 kgf / cm 2 .

[0188] Using photomasks with opening patterns of Φ80μm and Φ100μm, a direct imaging exposure machine (DI exposure apparatus, ORC MANUFACTURING CO.,LTD., Mms60) was used to expose a curable resin laminate with a PET film on a substrate in a single exposure (exposure dose: 300mJ / cm²). 2 Then, after standing at room temperature for 10 minutes, the PET film was peeled off. Development was then performed for 90 seconds using a 1% (w / w) Na₂CO₃ aqueous solution at 30°C and a jet pressure of 0.2 MPa, forming a cured resin laminate with openings of Φ80 μm and Φ100 μm. The cured resin laminate was washed with a washing solution at 25°C and a jet pressure of 0.1 MPa for 90 seconds, followed by exposure (exposure dose: 1000 mJ / cm²). 2 The substrate was heated to 170°C for 60 minutes to allow it to fully cure. Evaluation substrates with the cured material formed on them were then fabricated. The characteristics of the resulting evaluation substrates were evaluated as follows. The results are shown in Tables 2 and 3.

[0189] <Appearance Evaluation>

[0190] For the evaluation substrates of each embodiment and comparative example, pinholes and non-uniformity were visually observed. The evaluation of each item was carried out according to the following criteria.

[0191] (Pinhole)

[0192] 〇: No pinholes.

[0193] ×: There is a pinhole.

[0194] (Uneven)

[0195] 〇: No coating streaks.

[0196] ×: There are coating streaks.

[0197] <Preparation of Samples for Concealment Assessment>

[0198] In the above-mentioned <Preparation of Evaluation Substrate>, except that a substrate with a depth of 5μm and a length of 10mm was used as the substrate to make scratches on the circuit surface of a double-sided printed wiring board with a size of 150mm × 95mm and a board thickness of 0.4mm, the same steps were performed to prepare the concealment evaluation samples of each embodiment and comparative example.

[0199] For the concealment evaluation samples of each embodiment and comparative example, concealment was visually observed and evaluated according to the following criteria.

[0200] (concealment)

[0201] ◎: No damage.

[0202] 〇: There is minor damage.

[0203] ×: Damaged.

[0204] (Determination of linear thermal expansion coefficient (CTE))

[0205] The cured material was peeled off from the evaluation substrates of each embodiment and comparative example, and samples cut to obtain the measurement dimensions (3 mm × 10 mm) were used as test samples. The coefficient of thermal expansion (CTE) of each test sample was measured using a Hitachi Advanced Technology Co., Ltd. (TAMA6100) machine. The measurement conditions were as follows: a test load of 5 g, and the sample was heated from room temperature in stretch mode at a heating rate of 10 °C / min. This operation was repeated twice, and the average coefficient of linear thermal expansion (α2) calculated within the second temperature range of 200 °C to 250 °C was obtained.

[0206] (Resolution)

[0207] In the evaluation substrates of each embodiment and comparative example, the diameter of the opening end (Top) under Φ80μm and Φ100μm conditions was measured using SEM (manufactured by Nippon Electron Ltd., JSM6610LV) at a measurement magnification of 1000x, and the rate of change T relative to the design value was calculated using the following formula.

[0208] The rate of change of Φ80μm is T = 100 - diameter / 80 × 100.

[0209] The rate of change of Φ100μm is T = 100 - diameter / 100 × 100.

[0210] In the evaluation substrates of each embodiment and comparative example, the diameter of the bottom of the opening under Φ80μm and Φ100μm conditions was measured using an SEM (manufactured by Nippon Electron Ltd., JSM6610LV) at a measurement magnification of 1000x, and the rate of change B relative to the design value was calculated using the following formula.

[0211] The rate of change of Φ80μm B = 100 - diameter / 80 × 100.

[0212] The rate of change of Φ100μm B = 100 - diameter / 100 × 100.

[0213] Table 2

[0214] Table 3

[0215] Comparative Examples 1 and 2, being thin films, exhibited excellent resolution, but pinholes were present. Comparative Examples 3-7, being thick films compared to Comparative Examples 1 and 2, suppressed pinhole formation, but resulted in unevenness and decreased resolution.

[0216] On the other hand, according to Example 1, although the thickness is the same as that of Comparative Example 2, not only is the resolution excellent, but the generation of pinholes is also suppressed. Furthermore, the linear thermal expansion coefficient is also satisfactory, achieving a low rate of thermal expansion. In addition, in Examples 2-9, which are thicker films compared to Example 1, the generation of non-uniformity is also suppressed, and excellent results such as resolution are obtained. Furthermore, although the thickness is the same as that of Comparative Examples 3-7, the linear thermal expansion coefficient is reduced, further reducing the rate of thermal expansion. As described above, the manufacturing methods of each embodiment demonstrate that the generation of pinholes and non-uniformity is easily suppressed, and cured products with excellent resolution can be obtained even with thick films.

[0217] Industrial applicability

[0218] This invention provides a method for manufacturing a cured product with excellent appearance and excellent resolution even when the film is thick, and thus can be used in miniaturized, high-performance electronic devices, etc.

[0219] Cross-referencing of related applications

[0220] This application claims priority based on Japanese Patent Application No. 2023-187255, filed with the Japan Patent Office on October 31, 2023, the entire disclosure of which is incorporated herein by reference.

[0221] Explanation of reference numerals in the attached figures

[0222] 10: Cured product.

[0223] 20: Curable resin laminate.

[0224] P1: First membrane.

[0225] P4: First membrane.

[0226] D1: Dry film.

[0227] D4: Dry film.

[0228] Q: Substrate.

Claims

1. A method for manufacturing a solidified material, wherein, The method for manufacturing the solidified material includes: A lamination process, wherein a dry film having a first film and a curable resin layer is used to laminate the curable resin layer to obtain a curable resin laminate; and The curing process, in which the curable resin laminate is cured to obtain a cured product, involves curing the laminate. The filler content in the curable resin layer is 30% by mass or more, based on the total solids content. The cured resin layer has a high filler content surface and a low filler content surface. The high filler content surface is the surface area with a relatively high filler content, and the low filler content surface is the surface area with a relatively low filler content. The lamination process is a process in which the high filler content side of one pair of curable resin layers is sequentially stacked with the low filler content side of the other pair of curable resin layers.

2. The method for manufacturing a cured product as described in claim 1, wherein, The filler is silicon dioxide.

3. The method for manufacturing a cured product as described in claim 1 or 2, wherein, The thickness of the cured resin layer is less than 25 μm.

4. The method for manufacturing a cured product as described in claim 1 or 2, wherein, The curing process includes an exposure step, in which the entire curable resin laminate is irradiated with energy rays and each of the curable resin layers contained in the curable resin laminate is simultaneously exposed.

5. The method for manufacturing a cured product as described in claim 1 or 2, wherein, The lamination process is a process of laminating at least two or more layers of the curable resin.

6. The method for manufacturing a cured product as described in claim 1 or 2, wherein, The thickness of the curable resin laminate is 20 μm or more.

7. A cured product, which is a cured product formed by stacking a plurality of resin cured layers, wherein, The filler content in each resin cured layer is 30% by mass or more, based on the total solids content. The cured resin layer has a high filler content surface and a low filler content surface. The high filler content surface is the surface area with a relatively high filler content, and the low filler content surface is the surface area with a relatively low filler content. For a pair of adjacent resin cured layers, the high filler content surface of one resin cured layer is stacked with the low filler content surface of the other resin cured layer.

Images